Articles | Volume 24, issue 10
https://doi.org/10.5194/acp-24-5935-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-24-5935-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
24 May 2024
Research article | Highlight paper |
| 24 May 2024
| 24 May 2024
Extensive coverage of ultrathin tropical tropopause layer cirrus clouds revealed by balloon-borne lidar observations
Thomas Lesigne
CORRESPONDING AUTHOR
Laboratoire Atmosphères, Observations Spatiales (LATMOS/IPSL), Sorbonne Université, UVSQ, CNRS, Paris, France
François Ravetta
Laboratoire Atmosphères, Observations Spatiales (LATMOS/IPSL), Sorbonne Université, UVSQ, CNRS, Paris, France
Aurélien Podglajen
Laboratoire de Météorologie Dynamique (LMD/IPSL), École Polytechnique, Institut Polytechnique de Paris, Sorbonne Université, École Normale Supérieure, PSL Research University, CNRS, Paris, France
Vincent Mariage
Laboratoire Atmosphères, Observations Spatiales (LATMOS/IPSL), Sorbonne Université, UVSQ, CNRS, Paris, France
Jacques Pelon
Laboratoire Atmosphères, Observations Spatiales (LATMOS/IPSL), Sorbonne Université, UVSQ, CNRS, Paris, France
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Pierre Cadiou, Riwal Plougonven, Aurélien Podglajen, Albert Hertzog, and Alexandra Mac Farlane
EGUsphere, https://doi.org/10.5194/egusphere-2025-3208, https://doi.org/10.5194/egusphere-2025-3208, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Winds in the Equatorial region remain difficult to model. We take advantage of long-duration balloon campaigns from 2019 and 2021 to assess errors in winds between 18 and 20 km in a weather forecast model. Large errors persist: one third of the time, the error is larger than 3.5 meters per second. This has implications for research studies that calculate air mass trajectories in this transition region between the troposphere and the stratosphere.
Clair Duchamp, Bernard Legras, Aurélien Podglajen, Pasquale Sellitto, Adam E. Bourassa, Alexei Rozanov, Ghassan Taha, and Daniel J. Zawada
EGUsphere, https://doi.org/10.5194/egusphere-2025-3355, https://doi.org/10.5194/egusphere-2025-3355, 2025
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
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We analyzed the stratospheric aerosol plume from the 2022 Hunga eruption using satellite lidar data. We implemented a method to retrieve some aerosol properties, as standard products failed in this case. We found very high optical depth values in the days following the eruption, which decreased rapidly but remained elevated for months. Our results are broadly validated, though some satellite products underestimate the values due, in part, to the unusual aerosol size distribution in the plume.
Pasquale Sellitto, Redha Belhadji, Bernard Legras, Aurélien Podglajen, and Clair Duchamp
Atmos. Chem. Phys., 25, 6353–6364, https://doi.org/10.5194/acp-25-6353-2025, https://doi.org/10.5194/acp-25-6353-2025, 2025
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The Hunga Tonga–Hunga Ha’apai volcano erupted on 15 January 2022, producing the largest stratospheric aerosol perturbation of the last 30 years. Stratospheric volcanic aerosols usually produce a transient climate cooling; these impacts depend on volcanic aerosol composition/size, due to size-dependent interactions with solar/terrestrial radiation. We demonstrate that the Hunga Tonga–Hunga Ha’apai stratospheric aerosols have a larger cooling potential per unit mass than the past climate-relevant El Chichón (1984) and Pinatubo (1991) eruptions.
Xiaolu Yan, Paul Konopka, Felix Ploeger, and Aurélien Podglajen
Atmos. Chem. Phys., 25, 1289–1305, https://doi.org/10.5194/acp-25-1289-2025, https://doi.org/10.5194/acp-25-1289-2025, 2025
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Our study finds that the air mass fractions (AMFs) from the Asian boundary layer (ABL) to the polar regions are about 1.5 times larger than those from the same latitude band in the Southern Hemisphere. The transport of AMFs from the ABL to the polar vortex primarily occurs above 20 km and over timescales exceeding 2 years. Our analysis reveals a strong correlation between the polar pollutants and the AMFs from the ABL. About 20 % of SF6 in the polar stratosphere originates from the ABL.
Gérard Ancellet, Camille Viatte, Anne Boynard, François Ravetta, Jacques Pelon, Cristelle Cailteau-Fischbach, Pascal Genau, Julie Capo, Axel Roy, and Philippe Nédélec
Atmos. Chem. Phys., 24, 12963–12983, https://doi.org/10.5194/acp-24-12963-2024, https://doi.org/10.5194/acp-24-12963-2024, 2024
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Characterization of ozone pollution in urban areas benefited from a measurement campaign in summer 2022 in the Paris region. The analysis is based on 21 d of lidar and aircraft observations. The main objective is an analysis of the sensitivity of ozone pollution to the micrometeorological processes in the urban atmospheric boundary layer and the transport of regional pollution. The paper also discusses to what extent satellite observations can track observed ozone plumes.
Sullivan Carbone, Emmanuel D. Riviere, Mélanie Ghysels, Jérémie Burgalat, Georges Durry, Nadir Amarouche, Aurélien Podglajen, and Albert Hertzog
EGUsphere, https://doi.org/10.5194/egusphere-2024-3249, https://doi.org/10.5194/egusphere-2024-3249, 2024
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During the two first Strateole 2 campaigns, instruments have flown under super pressure balloons between 18 and 20 km for several weeks at the equator and performed in situ measurements of water vapor. The present article exposes the methodology used to quantify the modulation of water vapor by atmospheric waves and deep convective cases. This methodology allows to put to the fore the influence of atmospheric waves and extremely deep convection on the observed water vapor anomalies.
Julia Maillard, Jean-Christophe Raut, and François Ravetta
Geosci. Model Dev., 17, 3303–3320, https://doi.org/10.5194/gmd-17-3303-2024, https://doi.org/10.5194/gmd-17-3303-2024, 2024
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Atmospheric models struggle to reproduce the strong temperature inversions in the vicinity of the surface over forested areas in the Arctic winter. In this paper, we develop modified simplified versions of surface layer schemes widely used by the community. Our modifications are used to correct the fact that original schemes place strong limits on the turbulent collapse, leading to a lower surface temperature gradient at low wind speeds. Modified versions show a better performance.
Pasquale Sellitto, Redha Belhadji, Juan Cuesta, Aurélien Podglajen, and Bernard Legras
Atmos. Chem. Phys., 23, 15523–15535, https://doi.org/10.5194/acp-23-15523-2023, https://doi.org/10.5194/acp-23-15523-2023, 2023
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Record-breaking wildfires ravaged south-eastern Australia during the fire season 2019–2020. These fires injected a smoke plume in the stratosphere, which dispersed over the whole Southern Hemisphere and interacted with solar and terrestrial radiation. A number of detached smoke bubbles were also observed emanating from this plume and ascending quickly to over 35 km altitude. Here we study how absorption of radiation generated ascending motion of both the the hemispheric plume and the vortices.
Milena Corcos, Albert Hertzog, Riwal Plougonven, and Aurélien Podglajen
Atmos. Chem. Phys., 23, 6923–6939, https://doi.org/10.5194/acp-23-6923-2023, https://doi.org/10.5194/acp-23-6923-2023, 2023
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The role of gravity waves on tropical cirrus clouds and air-parcel dehydration was studied using the combination of Lagrangian observations of temperature fluctuations from superpressure balloons and a 1.5D model. The inclusion of the gravity waves to a reference simulation of a slow ascent around the cold-point tropopause drastically increases ice-crystal density, cloud fraction, and air-parcel dehydration, and it produces a crystal size distribution that agrees better with observations.
Richard Wilson, Clara Pitois, Aurélien Podglajen, Albert Hertzog, Milena Corcos, and Riwal Plougonven
Atmos. Meas. Tech., 16, 311–330, https://doi.org/10.5194/amt-16-311-2023, https://doi.org/10.5194/amt-16-311-2023, 2023
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Strateole-2 is an French–US initiative designed to study atmospheric events in the tropical upper troposphere–lower stratosphere. In this work, data from several superpressure balloons, capable of staying aloft at an altitude of 18–20 km for over 3 months, were used. The present article describes methods to detect the occurrence of atmospheric turbulence – one efficient process impacting the properties of the atmosphere composition via stirring and mixing.
Bernard Legras, Clair Duchamp, Pasquale Sellitto, Aurélien Podglajen, Elisa Carboni, Richard Siddans, Jens-Uwe Grooß, Sergey Khaykin, and Felix Ploeger
Atmos. Chem. Phys., 22, 14957–14970, https://doi.org/10.5194/acp-22-14957-2022, https://doi.org/10.5194/acp-22-14957-2022, 2022
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The long-duration atmospheric impact of the Tonga eruption in January 2022 is a plume of water and sulfate aerosols in the stratosphere that persisted for more than 6 months. We study this evolution using several satellite instruments and analyse the unusual behaviour of this plume as sulfates and water first moved down rapidly and then separated into two layers. We also report the self-organization in compact and long-lived patches.
Meryl Wimmer, Gwendal Rivière, Philippe Arbogast, Jean-Marcel Piriou, Julien Delanoë, Carole Labadie, Quitterie Cazenave, and Jacques Pelon
Weather Clim. Dynam., 3, 863–882, https://doi.org/10.5194/wcd-3-863-2022, https://doi.org/10.5194/wcd-3-863-2022, 2022
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The effect of deep convection representation on the jet stream above the cold front of an extratropical cyclone is investigated in the global numerical weather prediction model ARPEGE. Two simulations using different deep convection schemes are compared with (re)analysis datasets and NAWDEX airborne observations. A deeper jet stream is observed with the less active scheme. The diabatic origin of this difference is interpreted by backward Lagrangian trajectories and potential vorticity budgets.
Thibault Vaillant de Guélis, Gérard Ancellet, Anne Garnier, Laurent C.-Labonnote, Jacques Pelon, Mark A. Vaughan, Zhaoyan Liu, and David M. Winker
Atmos. Meas. Tech., 15, 1931–1956, https://doi.org/10.5194/amt-15-1931-2022, https://doi.org/10.5194/amt-15-1931-2022, 2022
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A new IIR-based cloud and aerosol discrimination (CAD) algorithm is developed using the IIR brightness temperature differences for cloud and aerosol features confidently identified by the CALIOP version 4 CAD algorithm. IIR classifications agree with the majority of V4 cloud identifications, reduce the ambiguity in a notable fraction of
not confidentV4 cloud classifications, and correct a few V4 misclassifications of cloud layers identified as dense dust or elevated smoke layers by CALIOP.
Lilian Loyer, Jean-Christophe Raut, Claudia Di Biagio, Julia Maillard, Vincent Mariage, and Jacques Pelon
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2021-326, https://doi.org/10.5194/amt-2021-326, 2021
Revised manuscript not accepted
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The Arctic is facing drastic climate changes, and more observations are needed to better understand what is happening. Unfortunately observations are limited in the High Arctic. To obtain more observations, multiples buoys equipped with lidar, have been deployed in this region. This paper presents an approach to estimate the optical properties of clouds, and solar plus terrestrial energies from lidar measurements in the Arctic.
Gwendal Rivière, Meryl Wimmer, Philippe Arbogast, Jean-Marcel Piriou, Julien Delanoë, Carole Labadie, Quitterie Cazenave, and Jacques Pelon
Weather Clim. Dynam., 2, 1011–1031, https://doi.org/10.5194/wcd-2-1011-2021, https://doi.org/10.5194/wcd-2-1011-2021, 2021
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Inacurracies in representing processes occurring at spatial scales smaller than the grid scales of the weather forecast models are important sources of forecast errors. This is the case of deep convection representation in models with 10 km grid spacing. We performed simulations of a real extratropical cyclone using a model with different representations of deep convection. These forecasts lead to different behaviors in the ascending air masses of the cyclone and the jet stream aloft.
Nuria Pilar Plaza, Aurélien Podglajen, Cristina Peña-Ortiz, and Felix Ploeger
Atmos. Chem. Phys., 21, 9585–9607, https://doi.org/10.5194/acp-21-9585-2021, https://doi.org/10.5194/acp-21-9585-2021, 2021
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We study the role of different processes in setting the lower stratospheric water vapour. We find that mechanisms involving ice microphysics and small-scale mixing produce the strongest increase in water vapour, in particular over the Asian Monsoon. Small-scale mixing has a special relevance as it improves the agreement with observations at seasonal and intra-seasonal timescales, contrary to the North American Monsoon case, in which large-scale temperatures still dominate its variability.
Didier Bruneau and Jacques Pelon
Atmos. Meas. Tech., 14, 4375–4402, https://doi.org/10.5194/amt-14-4375-2021, https://doi.org/10.5194/amt-14-4375-2021, 2021
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Taking advantage of Aeolus success and of our airborne lidar system expertise, we present a new spaceborne wind lidar design for operational Aeolus follow-on missions, keeping most of the initial lidar system but relying on a single Mach–Zehnder interferometer to relax operational constraints and reduce measurement bias. System parameters are optimized. Random and systematic errors are shown to be compliant with the initial mission requirements. In addition, the system allows unbiased retrieval.
Hugo Lestrelin, Bernard Legras, Aurélien Podglajen, and Mikail Salihoglu
Atmos. Chem. Phys., 21, 7113–7134, https://doi.org/10.5194/acp-21-7113-2021, https://doi.org/10.5194/acp-21-7113-2021, 2021
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Following the 2020 Australian fires, it was recently discovered that stratospheric wildfire smoke plumes self-organize as anticyclonic vortices that persist for months and rise by 10 km due to the radiative heating from the absorbing smoke. In this study, we show that smoke-charged vortices previously occurred in the aftermath of the 2017 Canadian fires. We use meteorological analysis to characterize this new object in geophysical fluid dynamics, which likely impacts radiation and climate.
Anne Garnier, Jacques Pelon, Nicolas Pascal, Mark A. Vaughan, Philippe Dubuisson, Ping Yang, and David L. Mitchell
Atmos. Meas. Tech., 14, 3253–3276, https://doi.org/10.5194/amt-14-3253-2021, https://doi.org/10.5194/amt-14-3253-2021, 2021
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The IIR Level 2 data products include cloud effective emissivities and cloud microphysical properties such as effective diameter (De) and ice or liquid water path estimates. This paper (Part I) describes the improvements in the V4 algorithms compared to those used in the version 3 (V3) release, while results are presented in a companion paper (Part II).
Anne Garnier, Jacques Pelon, Nicolas Pascal, Mark A. Vaughan, Philippe Dubuisson, Ping Yang, and David L. Mitchell
Atmos. Meas. Tech., 14, 3277–3299, https://doi.org/10.5194/amt-14-3277-2021, https://doi.org/10.5194/amt-14-3277-2021, 2021
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The IIR Level 2 data products include cloud effective emissivities and cloud microphysical properties such as effective diameter (De) and ice or liquid water path estimates. This paper (Part II) shows retrievals over ocean and describes the improvements made with respect to version 3 as a result of the significant changes implemented in the version 4 algorithms, which are presented in a companion paper (Part I).
Xiaolu Yan, Paul Konopka, Marius Hauck, Aurélien Podglajen, and Felix Ploeger
Atmos. Chem. Phys., 21, 6627–6645, https://doi.org/10.5194/acp-21-6627-2021, https://doi.org/10.5194/acp-21-6627-2021, 2021
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Inter-hemispheric transport is important for understanding atmospheric tracers because of the asymmetry in emissions between the Southern Hemisphere (SH) and Northern Hemisphere (NH). This study finds that the air masses from the NH extratropics to the atmosphere are about 5 times larger than those from the SH extratropics. The interplay between the Asian summer monsoon and westerly ducts triggers the cross-Equator transport from the NH to the SH in boreal summer and fall.
David L. A. Flack, Gwendal Rivière, Ionela Musat, Romain Roehrig, Sandrine Bony, Julien Delanoë, Quitterie Cazenave, and Jacques Pelon
Weather Clim. Dynam., 2, 233–253, https://doi.org/10.5194/wcd-2-233-2021, https://doi.org/10.5194/wcd-2-233-2021, 2021
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The representation of an extratropical cyclone in simulations of two climate models is studied by comparing them to observations of the international field campaign NAWDEX. We show that the current resolution used to run climate model projections (more than 100 km) is not enough to represent the life cycle accurately, but the use of 50 km resolution is good enough. Despite these encouraging results, cloud properties (partitioning liquid and solid) are found to be far from the observations.
Julia Maillard, François Ravetta, Jean-Christophe Raut, Vincent Mariage, and Jacques Pelon
Atmos. Chem. Phys., 21, 4079–4101, https://doi.org/10.5194/acp-21-4079-2021, https://doi.org/10.5194/acp-21-4079-2021, 2021
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Clouds remain a major source of uncertainty in understanding the Arctic climate, due in part to the lack of measurements over the sea ice. In this paper, we exploit a series of lidar profiles acquired from autonomous drifting buoys deployed in the Arctic Ocean and derive a statistic of low cloud frequency and macrophysical properties. We also show that clouds contribute to warm the surface in the shoulder seasons but not significantly from May to September.
Setigui Aboubacar Keita, Eric Girard, Jean-Christophe Raut, Maud Leriche, Jean-Pierre Blanchet, Jacques Pelon, Tatsuo Onishi, and Ana Cirisan
Geosci. Model Dev., 13, 5737–5755, https://doi.org/10.5194/gmd-13-5737-2020, https://doi.org/10.5194/gmd-13-5737-2020, 2020
Melody A. Avery, Robert A. Ryan, Brian J. Getzewich, Mark A. Vaughan, David M. Winker, Yongxiang Hu, Anne Garnier, Jacques Pelon, and Carolus A. Verhappen
Atmos. Meas. Tech., 13, 4539–4563, https://doi.org/10.5194/amt-13-4539-2020, https://doi.org/10.5194/amt-13-4539-2020, 2020
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CALIOP data users will find more cloud layers detected in V4, with edges that extend further than in V3, for an increase in total atmospheric cloud volume of 6 %–9 % for high-confidence cloud phases and 1 %–2 % for all cloudy bins, including cloud fringes and unknown cloud phases. In V4 there are many fewer cloud layers identified as horizontally oriented ice, particularly in the 3° off-nadir view. Depolarization at 532 nm is the predominant parameter determining cloud thermodynamic phase.
Aurélien Podglajen, Albert Hertzog, Riwal Plougonven, and Bernard Legras
Atmos. Chem. Phys., 20, 9331–9350, https://doi.org/10.5194/acp-20-9331-2020, https://doi.org/10.5194/acp-20-9331-2020, 2020
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Thanks to the increase in resolution, numerical weather prediction models resolve a growing fraction of the gravity wave (GW) spectrum. Here, we assess the representation of Lagrangian GW fluctuations by comparing trajectories in the models to long-duration balloon observations. Most characteristics of the observed GW spectrum, such as near-inertial oscillations, are qualitatively present. However, the variability remains underestimated, emphasizing the continuous need for GW parameterizations.
Antonin Zabukovec, Gerard Ancellet, Iwan E. Penner, Mikhail Arshinov, Valery Kozlov, Jacques Pelon, Jean-Daniel Paris, Grigory Kokhanenko, Yuri S. Balin, Dmitry Chernov, and Boris D. Belan
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-195, https://doi.org/10.5194/acp-2020-195, 2020
Preprint withdrawn
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Description of two aircraft campaigns results carried out over Siberia in 2013 and 2017 to characterize aerosol emission. A methodology is proposed to derive the aerosol types using transport model and satellite observations. The extinction to backscatter ratio for each aerosol types is reported as it is a key parameter to constrain their radiative impact. These results are compared to previous work conducted in other regions and to aerosol data products observed by spaceborne lidars.
Xiaolu Yan, Paul Konopka, Felix Ploeger, Aurélien Podglajen, Jonathon S. Wright, Rolf Müller, and Martin Riese
Atmos. Chem. Phys., 19, 15629–15649, https://doi.org/10.5194/acp-19-15629-2019, https://doi.org/10.5194/acp-19-15629-2019, 2019
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The Asian and North American summer monsoons (ASM and NASM) have considerable influence on stratospheric chemistry and physics. More air mass is transported from the monsoon regions to the tropical stratosphere when the tracers are released clearly below the tropopause than when they are released close to the tropopause. Results for different altitudes of air origin reveal two transport pathways (monsoon and tropical) from the upper troposphere over the monsoon regions to the tropical pipe.
Matthias Nützel, Aurélien Podglajen, Hella Garny, and Felix Ploeger
Atmos. Chem. Phys., 19, 8947–8966, https://doi.org/10.5194/acp-19-8947-2019, https://doi.org/10.5194/acp-19-8947-2019, 2019
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We investigate the transport pathways of water vapour from the upper troposphere in the Asian monsoon region to the stratosphere. In the employed chemistry-transport model we use a tagging method, such that the impact of different source regions on the stratospheric water vapour budget can be quantified. A key finding is that the Asian monsoon (compared to other source regions) is very efficient in transporting air masses and water vapour to the tropical and extratropical stratosphere.
Quitterie Cazenave, Marie Ceccaldi, Julien Delanoë, Jacques Pelon, Silke Groß, and Andrew Heymsfield
Atmos. Meas. Tech., 12, 2819–2835, https://doi.org/10.5194/amt-12-2819-2019, https://doi.org/10.5194/amt-12-2819-2019, 2019
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The impact of ice clouds on the water cycle and radiative budget is still uncertain due to the complexity of cloud processes that makes it difficult to acquire adequate observations of ice cloud properties and parameterize them into climate and weather prediction models. In this paper we present the latest refinements brought to the DARDAR-CLOUD product, which contains ice cloud microphysical properties retrieved from the cloud radar and lidar measurements from the A-Train space mission.
Aurélien Podglajen and Felix Ploeger
Atmos. Chem. Phys., 19, 1767–1783, https://doi.org/10.5194/acp-19-1767-2019, https://doi.org/10.5194/acp-19-1767-2019, 2019
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The age spectrum (distribution of transit times) provides a compact description of transport from the surface to a given point in the atmosphere. It also determines the surface-emitted tracer content of an air parcel. We propose a method to invert this relation in order to retrieve age spectra from tracer concentrations and demonstrate its feasibility in idealized and model setups. Applied to observations, the approach might help to better constrain atmospheric transport timescales.
Zhaoyan Liu, Jayanta Kar, Shan Zeng, Jason Tackett, Mark Vaughan, Melody Avery, Jacques Pelon, Brian Getzewich, Kam-Pui Lee, Brian Magill, Ali Omar, Patricia Lucker, Charles Trepte, and David Winker
Atmos. Meas. Tech., 12, 703–734, https://doi.org/10.5194/amt-12-703-2019, https://doi.org/10.5194/amt-12-703-2019, 2019
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We describe the enhancements made to the cloud–aerosol discrimination (CAD) algorithms used to produce the CALIPSO version 4 (V4) data products. Revisions to the CAD probability distribution functions have greatly improved the recognition of aerosol layers lofted into the upper troposphere, and CAD is now applied to all layers detected in the stratosphere and all layers detected at single-shot resolution. Detailed comparisons show significant improvements relative to previous versions.
Gerard Ancellet, Iogannes E. Penner, Jacques Pelon, Vincent Mariage, Antonin Zabukovec, Jean Christophe Raut, Grigorii Kokhanenko, and Yuri S. Balin
Atmos. Meas. Tech., 12, 147–168, https://doi.org/10.5194/amt-12-147-2019, https://doi.org/10.5194/amt-12-147-2019, 2019
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Aerosol type seasonal variability and sources in Siberia are obtained from an automatic 808 nm micropulse lidar. A total of 540 aerosol backscatter vertical profiles have been retrieved using careful lidar calibration. Aerosol optical depth is retrieved using sun-photometer complementary observations and an aerosol source apportionment based on aerosol transport model simulations. Comparisons with satellite observations are discussed for three case studies.
Mark Vaughan, Anne Garnier, Damien Josset, Melody Avery, Kam-Pui Lee, Zhaoyan Liu, William Hunt, Jacques Pelon, Yongxiang Hu, Sharon Burton, Johnathan Hair, Jason L. Tackett, Brian Getzewich, Jayanta Kar, and Sharon Rodier
Atmos. Meas. Tech., 12, 51–82, https://doi.org/10.5194/amt-12-51-2019, https://doi.org/10.5194/amt-12-51-2019, 2019
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The version 4 (V4) release of the CALIPSO data products includes substantial improvements to the calibration of the CALIOP 1064 nm channel. In this paper we review the fundamentals of 1064 nm lidar calibration, explain the motivations for the changes made to the algorithm, and describe the mechanics of the V4 calibration technique. Internal consistency checks and comparisons to collocated high spectral resolution lidar measurements show the V4 1064 nm calibration coefficients to within ~ 3 %.
David L. Mitchell, Anne Garnier, Jacques Pelon, and Ehsan Erfani
Atmos. Chem. Phys., 18, 17325–17354, https://doi.org/10.5194/acp-18-17325-2018, https://doi.org/10.5194/acp-18-17325-2018, 2018
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To realistically model a changing climate, global measurements of cirrus cloud ice-particle number concentration (N) and size (De) are needed, through which one may infer the general mechanism of ice formation. A satellite remote sensing method was developed to measure N and De. It was found that N was highest and De lowest at high latitudes. In the Arctic, cirrus clouds occurred much more often during winter, which may have an impact on mid-latitude winter weather.
Aurélien Podglajen, Riwal Plougonven, Albert Hertzog, and Eric Jensen
Atmos. Chem. Phys., 18, 10799–10823, https://doi.org/10.5194/acp-18-10799-2018, https://doi.org/10.5194/acp-18-10799-2018, 2018
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Using a simplified analytical setup, we show that the temperature and wind fluctuations due to an atmospheric gravity wave can induce a localization of ice crystals in a specific region of the wave. In that region, the air is nearly saturated and the vertical wind anomaly is positive. As a consequence, reversible gravity wave motions have an irreversible impact (mean upward motion) on the ice crystals. Our findings are consistent with observations of cirrus clouds near the tropical tropopause.
Liubov Poshyvailo, Rolf Müller, Paul Konopka, Gebhard Günther, Martin Riese, Aurélien Podglajen, and Felix Ploeger
Atmos. Chem. Phys., 18, 8505–8527, https://doi.org/10.5194/acp-18-8505-2018, https://doi.org/10.5194/acp-18-8505-2018, 2018
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Water vapour (H2O) in the UTLS is a key player for global radiation, which is critical for predictions of future climate change. We investigate the effects of current uncertainties in tropopause temperature, horizontal transport and small-scale mixing on simulated H2O, using the Chemical Lagrangian Model of the Stratosphere. Our sensitivity studies provide new insights into the leading processes controlling stratospheric H2O, important for assessing and improving climate model projections.
Anne Garnier, Thierry Trémas, Jacques Pelon, Kam-Pui Lee, Delphine Nobileau, Lydwine Gross-Colzy, Nicolas Pascal, Pascale Ferrage, and Noëlle A. Scott
Atmos. Meas. Tech., 11, 2485–2500, https://doi.org/10.5194/amt-11-2485-2018, https://doi.org/10.5194/amt-11-2485-2018, 2018
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Residual calibration biases affecting CALIPSO IIR Version 1 calibrated radiances in the Northern Hemisphere are analyzed and reduced through in-depth analysis of the IIR internal calibration procedure in conjunction with observations such as statistical comparisons with similar MODIS/Aqua channels.
Jayanta Kar, Mark A. Vaughan, Kam-Pui Lee, Jason L. Tackett, Melody A. Avery, Anne Garnier, Brian J. Getzewich, William H. Hunt, Damien Josset, Zhaoyan Liu, Patricia L. Lucker, Brian Magill, Ali H. Omar, Jacques Pelon, Raymond R. Rogers, Travis D. Toth, Charles R. Trepte, Jean-Paul Vernier, David M. Winker, and Stuart A. Young
Atmos. Meas. Tech., 11, 1459–1479, https://doi.org/10.5194/amt-11-1459-2018, https://doi.org/10.5194/amt-11-1459-2018, 2018
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We present the motivation for and the implementation of the version 4.1 nighttime 532 nm parallel-channel calibration of the CALIOP lidar. The accuracy of calibration is significantly improved by raising the molecular normalization altitude from 30–34 km to 36–39 km to substantially reduce stratospheric aerosol contamination. The new calibration procedure eliminates biases in earlier versions and leads to an improved representation of stratospheric aerosols.
Lucia T. Deaconu, Fabien Waquet, Damien Josset, Nicolas Ferlay, Fanny Peers, François Thieuleux, Fabrice Ducos, Nicolas Pascal, Didier Tanré, Jacques Pelon, and Philippe Goloub
Atmos. Meas. Tech., 10, 3499–3523, https://doi.org/10.5194/amt-10-3499-2017, https://doi.org/10.5194/amt-10-3499-2017, 2017
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This study presents a comparison between active (CALIOP) and passive (POLDER) remote sensing methods, developed for retrieving aerosol above-cloud optical and microphysical properties. Main results show a good agreement when the aerosol microphysics is dominated by fine-mode particles or coarse-mode dust or when the aerosol layer is well separated from the cloud below. The paper is also focused on understanding the differences between the retrievals and the limitations of each method.
Leslie David, Olivier Bock, Christian Thom, Pierre Bosser, and Jacques Pelon
Atmos. Meas. Tech., 10, 2745–2758, https://doi.org/10.5194/amt-10-2745-2017, https://doi.org/10.5194/amt-10-2745-2017, 2017
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The Raman lidar ability to retrieve atmospheric water vapor with high accuracy makes it a premium instrument in different research fields such as climatology, meteorology, or calibration of GNSS altimetry data. In order to achieve long-term stability of the measurements, the system has to be carefully calibrated. In this work we strove to investigate and mitigate the error and instability sources through numerical simulations as well as experimental tests.
Anne Garnier, Noëlle A. Scott, Jacques Pelon, Raymond Armante, Laurent Crépeau, Bruno Six, and Nicolas Pascal
Atmos. Meas. Tech., 10, 1403–1424, https://doi.org/10.5194/amt-10-1403-2017, https://doi.org/10.5194/amt-10-1403-2017, 2017
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An assessment of IIR radiances after 9.5 years of nearly continuous operation since June 2006 is presented. First, IIR is compared with similar MODIS or SEVIRI channels in various conditions. Second, clear sky measurements in each channel are compared with simulations. The first approach detects biases and/or trends, and the second approach contributes to identifying which channel deviates from the other. The analyses are based on simulations using the 4A/OP radiative transfer model.
Claudia Di Biagio, Paola Formenti, Lionel Doppler, Cécile Gaimoz, Noel Grand, Gerard Ancellet, Jean-Luc Attié, Silvia Bucci, Philippe Dubuisson, Federico Fierli, Marc Mallet, and François Ravetta
Atmos. Chem. Phys., 16, 10591–10607, https://doi.org/10.5194/acp-16-10591-2016, https://doi.org/10.5194/acp-16-10591-2016, 2016
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Pollution aerosols strongly influence the composition of the Western Mediterranean, but at present little is known on their optical properties. Here, we report observations of pollution aerosols measured during the TRAQA airborne campaign in summer 2012. Data from this study indicate a large variability of the absorption for pollution particles. This variability strongly influences their direct radiative effect, with possible consequences on the hydrological cycle in this part of the basin.
Jean-Pierre Chaboureau, Cyrille Flamant, Thibaut Dauhut, Cécile Kocha, Jean-Philippe Lafore, Chistophe Lavaysse, Fabien Marnas, Mohamed Mokhtari, Jacques Pelon, Irene Reinares Martínez, Kerstin Schepanski, and Pierre Tulet
Atmos. Chem. Phys., 16, 6977–6995, https://doi.org/10.5194/acp-16-6977-2016, https://doi.org/10.5194/acp-16-6977-2016, 2016
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The Fennec field campaign conducted in June 2011 led to the first observational data set ever obtained that documents the Saharan atmospheric boundary layer under the influence of the heat low. In addition to the aircraft operation, four dust forecasts were run at low and high resolutions with convection-parameterizing and convection-permitting models, respectively. The unique airborne and ground-based data sets allowed the first ever intercomparison of dust forecasts over the western Sahara.
Gerard Ancellet, Jacques Pelon, Julien Totems, Patrick Chazette, Ariane Bazureau, Michaël Sicard, Tatiana Di Iorio, Francois Dulac, and Marc Mallet
Atmos. Chem. Phys., 16, 4725–4742, https://doi.org/10.5194/acp-16-4725-2016, https://doi.org/10.5194/acp-16-4725-2016, 2016
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A multi-lidar analysis conducted in the Mediterranean basin compares the impact of the long-range transport of North American biomass burning aerosols with the role of frequently observed Saharan dust outbreaks. This paper provides a detailed analysis of the potential North American aerosol sources, their transport to Europe and the mixing of different aerosol sources, using simulations of a particle dispersion model and lidar measurements of the aerosol optical properties.
Aurélien Podglajen, Riwal Plougonven, Albert Hertzog, and Bernard Legras
Atmos. Chem. Phys., 16, 3881–3902, https://doi.org/10.5194/acp-16-3881-2016, https://doi.org/10.5194/acp-16-3881-2016, 2016
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The Weather Research and Forecast model is used to simulate a large-scale tropical tropopause layer (TTL) cirrus. Validated with satellite observations, the simulation shows that several clouds successively form due to a large-scale uplift initiated by the intrusion of air from the midlatitudes. The simulated cloud field is found as sensitive to the initial condition as it is to the choice of the microphysics parametrisation. The cloud impacts on the radiative and water budgets are estimated.
Patrick Chazette, Julien Totems, Gérard Ancellet, Jacques Pelon, and Michaël Sicard
Atmos. Chem. Phys., 16, 2863–2875, https://doi.org/10.5194/acp-16-2863-2016, https://doi.org/10.5194/acp-16-2863-2016, 2016
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We performed synergetic active and passive remote-sensing observations at Minorca (Spain), over more than 3 weeks in spring 2013. We characterized the aerosol optical properties and type using a combination of Rayleigh–Mie–Raman lidar and sun-photometer data. Results show a high variability due to changing atmospheric transport regimes and aerosol sources. Such variability significantly influences the radiative balance through the entire atmosphere and then the climate of the Mediterranean area.
M. Mallet, F. Dulac, P. Formenti, P. Nabat, J. Sciare, G. Roberts, J. Pelon, G. Ancellet, D. Tanré, F. Parol, C. Denjean, G. Brogniez, A. di Sarra, L. Alados-Arboledas, J. Arndt, F. Auriol, L. Blarel, T. Bourrianne, P. Chazette, S. Chevaillier, M. Claeys, B. D'Anna, Y. Derimian, K. Desboeufs, T. Di Iorio, J.-F. Doussin, P. Durand, A. Féron, E. Freney, C. Gaimoz, P. Goloub, J. L. Gómez-Amo, M. J. Granados-Muñoz, N. Grand, E. Hamonou, I. Jankowiak, M. Jeannot, J.-F. Léon, M. Maillé, S. Mailler, D. Meloni, L. Menut, G. Momboisse, J. Nicolas, T. Podvin, V. Pont, G. Rea, J.-B. Renard, L. Roblou, K. Schepanski, A. Schwarzenboeck, K. Sellegri, M. Sicard, F. Solmon, S. Somot, B Torres, J. Totems, S. Triquet, N. Verdier, C. Verwaerde, F. Waquet, J. Wenger, and P. Zapf
Atmos. Chem. Phys., 16, 455–504, https://doi.org/10.5194/acp-16-455-2016, https://doi.org/10.5194/acp-16-455-2016, 2016
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The aim of this article is to present an experimental campaign over the Mediterranean focused on aerosol-radiation measurements and modeling. Results indicate an important atmospheric loading associated with a moderate absorbing ability of mineral dust. Observations suggest a complex vertical structure and size distributions characterized by large aerosols within dust plumes. The radiative effect is highly variable, with negative forcing over the Mediterranean and positive over northern Africa.
T. Dinh, A. Podglajen, A. Hertzog, B. Legras, and R. Plougonven
Atmos. Chem. Phys., 16, 35–46, https://doi.org/10.5194/acp-16-35-2016, https://doi.org/10.5194/acp-16-35-2016, 2016
A. Garnier, J. Pelon, M. A. Vaughan, D. M. Winker, C. R. Trepte, and P. Dubuisson
Atmos. Meas. Tech., 8, 2759–2774, https://doi.org/10.5194/amt-8-2759-2015, https://doi.org/10.5194/amt-8-2759-2015, 2015
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Cloud absorption optical depths retrieved at 12.05 microns are compared to extinction optical depths retrieved at 0.532 microns from perfectly co-located observations of single-layered semi-transparent cirrus over oceans made by the space-borne CALIPSO IIR infrared radiometer and CALIOP lidar. A new relationship describing the temperature-dependent effect of multiple scattering in the CALIOP retrievals is derived and discussed.
L. Marelle, J.-C. Raut, J. L. Thomas, K. S. Law, B. Quennehen, G. Ancellet, J. Pelon, A. Schwarzenboeck, and J. D. Fast
Atmos. Chem. Phys., 15, 3831–3850, https://doi.org/10.5194/acp-15-3831-2015, https://doi.org/10.5194/acp-15-3831-2015, 2015
N. Bègue, P. Tulet, J. Pelon, B. Aouizerats, A. Berger, and A. Schwarzenboeck
Atmos. Chem. Phys., 15, 3497–3516, https://doi.org/10.5194/acp-15-3497-2015, https://doi.org/10.5194/acp-15-3497-2015, 2015
T. Fauchez, P. Dubuisson, C. Cornet, F. Szczap, A. Garnier, J. Pelon, and K. Meyer
Atmos. Meas. Tech., 8, 633–647, https://doi.org/10.5194/amt-8-633-2015, https://doi.org/10.5194/amt-8-633-2015, 2015
F. Marenco, V. Amiridis, E. Marinou, A. Tsekeri, and J. Pelon
Atmos. Chem. Phys., 14, 11871–11881, https://doi.org/10.5194/acp-14-11871-2014, https://doi.org/10.5194/acp-14-11871-2014, 2014
G. Ancellet, J. Pelon, Y. Blanchard, B. Quennehen, A. Bazureau, K. S. Law, and A. Schwarzenboeck
Atmos. Chem. Phys., 14, 8235–8254, https://doi.org/10.5194/acp-14-8235-2014, https://doi.org/10.5194/acp-14-8235-2014, 2014
C. Jouan, J. Pelon, E. Girard, G. Ancellet, J. P. Blanchet, and J. Delanoë
Atmos. Chem. Phys., 14, 1205–1224, https://doi.org/10.5194/acp-14-1205-2014, https://doi.org/10.5194/acp-14-1205-2014, 2014
P. Dubuisson, H. Herbin, F. Minvielle, M. Compiègne, F. Thieuleux, F. Parol, and J. Pelon
Atmos. Meas. Tech., 7, 359–371, https://doi.org/10.5194/amt-7-359-2014, https://doi.org/10.5194/amt-7-359-2014, 2014
J.-F. Gayet, V. Shcherbakov, L. Bugliaro, A. Protat, J. Delanoë, J. Pelon, and A. Garnier
Atmos. Chem. Phys., 14, 899–912, https://doi.org/10.5194/acp-14-899-2014, https://doi.org/10.5194/acp-14-899-2014, 2014
C. Tsamalis, A. Chédin, J. Pelon, and V. Capelle
Atmos. Chem. Phys., 13, 11235–11257, https://doi.org/10.5194/acp-13-11235-2013, https://doi.org/10.5194/acp-13-11235-2013, 2013
O. Bock, P. Bosser, T. Bourcy, L. David, F. Goutail, C. Hoareau, P. Keckhut, D. Legain, A. Pazmino, J. Pelon, K. Pipis, G. Poujol, A. Sarkissian, C. Thom, G. Tournois, and D. Tzanos
Atmos. Meas. Tech., 6, 2777–2802, https://doi.org/10.5194/amt-6-2777-2013, https://doi.org/10.5194/amt-6-2777-2013, 2013
O. Sourdeval, L. C. -Labonnote, G. Brogniez, O. Jourdan, J. Pelon, and A. Garnier
Atmos. Chem. Phys., 13, 8229–8244, https://doi.org/10.5194/acp-13-8229-2013, https://doi.org/10.5194/acp-13-8229-2013, 2013
Related subject area
Subject: Clouds and Precipitation | Research Activity: Remote Sensing | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Impact of weather systems on observed precipitation at Ny-Ålesund (Svalbard)
Analysis of ship emission effects on clouds over the southeastern Atlantic using geostationary satellite observations
Relationship between latent and radiative heating fields of tropical cloud systems using synergistic satellite observations
Shallow cloud variability in Houston, Texas, during the ESCAPE and TRACER field experiments
How does the lifetime of detrained cirrus impact the high-cloud radiative effect in the tropics?
Anvil–radiation diurnal interaction: shortwave radiative-heating destabilization driving the diurnal variation of convective anvil outflow and its modulation on the radiative cancellation
Opinion: Inferring Process from Snapshots of Cloud Systems
Impact of wildfire smoke on Arctic cirrus formation – Part 1: Analysis of MOSAiC 2019–2020 observations
A new aggregation and riming discrimination algorithm based on polarimetric weather radars
Study of optical scattering properties and direct radiative effects of high-altitude cirrus clouds in Barcelona, Spain, with 4 years of lidar measurements
Co-variability drives the inverted-V sensitivity between liquid water path and droplet concentrations
Life cycle studies and liquid-phase characterization of Arctic mixed-phase clouds: MOSAiC 2019–2020 results
Lightning declines over shipping lanes following regulation of fuel sulfur emissions
Post-return stroke VHF electromagnetic activity in north-western Mediterranean cloud-to-ground lightning flashes
A machine learning-based perspective on deep convective clouds and their organisation in 3D. Part I: Influence of deep convective cores on the cloud life-cycle
A machine learning-based perspective on deep convective clouds and their organisation in 3D. Part II: Spatial-temporal patterns of convective organisation
Technical note: Applicability of physics-based and machine-learning-based algorithms of a geostationary satellite in retrieving the diurnal cycle of cloud base height
Observing convective activities in complex convective organizations and their contributions to precipitation and anvil cloud amounts
Advances in CALIPSO (IIR) cirrus cloud property retrievals – Part 1: Methods and testing
Advances in CALIPSO (IIR) cirrus cloud property retrievals – Part 2: Global estimates of the fraction of cirrus clouds affected by homogeneous ice nucleation
Weak liquid water path response in ship tracks
Air mass history linked to the development of Arctic mixed-phase clouds
Distinct structure, radiative effects, and precipitation characteristics of deep convection systems in the Tibetan Plateau compared to the tropical Indian Ocean
The correlation between Arctic sea ice, cloud phase and radiation using A-Train satellites
Technical note: Retrieval of the supercooled liquid fraction in mixed-phase clouds from Himawari-8 observations
Characterisation of low-base and mid-base clouds and their thermodynamic phase over the Southern Ocean and Arctic marine regions
A survey of radiative and physical properties of North Atlantic mesoscale cloud morphologies from multiple identification methodologies
The effects of warm-air intrusions in the high Arctic on cirrus clouds
The characteristics of cloud macro-parameters caused by the seeder–feeder process inside clouds measured by millimeter-wave cloud radar in Xi'an, China
Shallow- and deep-convection characteristics in the greater Houston, Texas, area using cell tracking methodology
Observations of the macrophysical properties of cumulus cloud fields over the tropical western Pacific and their connection to meteorological variables
A Lagrangian perspective on the lifecycle and cloud radiative effect of deep convective clouds over Africa
Daytime variation in the aerosol indirect effect for warm marine boundary layer clouds in the eastern North Atlantic
Technical note: Bimodal parameterizations of in situ ice cloud particle size distributions
Inter-relations of precipitation, aerosols, and clouds over Andalusia, southern Spain, revealed by the Andalusian Global ObseRvatory of the Atmosphere (AGORA)
On the relationship between mesoscale cellular convection and meteorological forcing: comparing the Southern Ocean against the North Pacific
Aerosol-related effects on the occurrence of heterogeneous ice formation over Lauder, New Zealand ∕ Aotearoa
Low-level Arctic clouds: a blind zone in our knowledge of the radiation budget
Climatologically invariant scale invariance seen in distributions of cloud horizontal sizes
Variability and properties of liquid-dominated clouds over the ice-free and sea-ice-covered Arctic Ocean
Asymmetries in cloud microphysical properties ascribed to sea ice leads via water vapour transport in the central Arctic
Quantifying the dependence of drop spectrum width on cloud drop number concentration for cloud remote sensing
The evolution of deep convective systems and their associated cirrus outflows
Wildfire smoke triggers cirrus formation: lidar observations over the eastern Mediterranean
Rapid saturation of cloud water adjustments to shipping emissions
Sensitivities of cloud radiative effects to large-scale meteorology and aerosols from global observations
Distinct secondary ice production processes observed in radar Doppler spectra: insights from a case study
Investigating the development of clouds within marine cold-air outbreaks
Detection of large-scale cloud microphysical changes within a major shipping corridor after implementation of the International Maritime Organization 2020 fuel sulfur regulations
Examining cloud vertical structure and radiative effects from satellite retrievals and evaluation of CMIP6 scenarios
Kerstin Ebell, Christian Buhren, Rosa Gierens, Giovanni Chellini, Melanie Lauer, Andreas Walbröl, Sandro Dahlke, Pavel Krobot, and Mario Mech
Atmos. Chem. Phys., 25, 7315–7342, https://doi.org/10.5194/acp-25-7315-2025, https://doi.org/10.5194/acp-25-7315-2025, 2025
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Ground-based observations of precipitation are rare in the Arctic. Since 2017, additional temporally highly resolved precipitation measurements have been carried out by a precipitation gauge and an optical precipitation sensor at Ny-Ålesund, Svalbard. These new data facilitate the distinction between liquid and solid precipitation. Using reanalysis data, we also find that water vapor transport contributes strongly to precipitation and especially to extreme precipitation events.
Nikos Benas, Jan Fokke Meirink, Rob Roebeling, and Martin Stengel
Atmos. Chem. Phys., 25, 6957–6973, https://doi.org/10.5194/acp-25-6957-2025, https://doi.org/10.5194/acp-25-6957-2025, 2025
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This study examines how ship emissions affect clouds over a shipping corridor in the southeastern Atlantic. Using satellite data from 2004 to 2023, we find that ship emissions increase the number of cloud droplets while reducing their size and slightly decrease cloud water content. Effects on seasonal and daily patterns vary based on regional factors. The impact of emissions weakened after stricter regulations were implemented in 2020.
Xiaoting Chen, Claudia J. Stubenrauch, and Giulio Mandorli
Atmos. Chem. Phys., 25, 6857–6880, https://doi.org/10.5194/acp-25-6857-2025, https://doi.org/10.5194/acp-25-6857-2025, 2025
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Strongly precipitating mesoscale convective systems produce a large amount of diabatic heating of the atmosphere, influencing atmospheric circulation. Their complete 3D description, attained by machine learning techniques in combination with satellite observations, has enabled a detailed study of the relationship between latent and radiative heating in these cloud systems. Convective organization increases both the average and the vertical gradient of radiative effects of the mesoscale convective systems.
Zackary Mages, Pavlos Kollias, Bernat Puigdomènech Treserras, Paloma Borque, and Mariko Oue
Atmos. Chem. Phys., 25, 6025–6045, https://doi.org/10.5194/acp-25-6025-2025, https://doi.org/10.5194/acp-25-6025-2025, 2025
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Convective clouds are a key component of the climate system. Using remote sensing observations during two field experiments in Houston, Texas, we identify four diurnal patterns of shallow convective clouds. We find areas more frequently experiencing shallow convective clouds, and we find areas where the vertical extent of shallow convective clouds is higher and where they are more likely to precipitate. This provides insight into the complicated environment that forms these clouds in Houston.
George Horner and Edward Gryspeerdt
Atmos. Chem. Phys., 25, 5617–5631, https://doi.org/10.5194/acp-25-5617-2025, https://doi.org/10.5194/acp-25-5617-2025, 2025
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This work tracks the life cycle of thin cirrus clouds that flow out of tropical convective storms. These cirrus clouds are found to have a warming effect on the atmosphere over their whole lifetime. Thin cirrus that originate from land origin convection warm more than those of ocean origin. Moreover, if the lifetime of these cirrus clouds increase, the warming they exert over their whole lifetime also increases. These results help us understand how these clouds might change in a future climate.
Zhenquan Wang
Atmos. Chem. Phys., 25, 5021–5039, https://doi.org/10.5194/acp-25-5021-2025, https://doi.org/10.5194/acp-25-5021-2025, 2025
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Convective anvil outflow directly driven by the shortwave radiative-heating destabilization is strong during the daytime, whereas the outflow contributed by the longwave radiative cooling through radiative destabilization and circulation is weak. This leads to the diurnal variation in the convection-producing anvil clouds, which in turn can influence the radiative energy budget.
Graham Feingold, Franziska Glassmeier, Jianhao Zhang, and Fabian Hoffmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-1869, https://doi.org/10.5194/egusphere-2025-1869, 2025
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Scientists usually use snapshots of atmospheric data to glean understanding of time-evolving atmospheric processes. We examine how much can be learned about processes from snapshots using examples from cloud and atmospheric physics. We couch the analysis in terms of Boltzmann's theory of ergodic systems, space-time-exchange, and the Deborah number -- concepts that are commonly applied in other branches of physics. We discuss the reasons for the varying degrees of success.
Albert Ansmann, Cristofer Jimenez, Johanna Roschke, Johannes Bühl, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Tom Gaudek, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 4847–4866, https://doi.org/10.5194/acp-25-4847-2025, https://doi.org/10.5194/acp-25-4847-2025, 2025
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In this study, we focus on the potential impact of wildfire smoke on cirrus formation. For the first time, state-of-the-art aerosol and cirrus observations with lidar and radar, presented in this paper (Part 1 of a series of two articles), are closely linked to the comprehensive modeling of gravity-wave-induced ice nucleation in cirrus evolution processes, presented in a companion paper (Part 2). We found a clear impact of wildfire smoke on cirrus evolution.
Armin Blanke, Mathias Gergely, and Silke Trömel
Atmos. Chem. Phys., 25, 4167–4184, https://doi.org/10.5194/acp-25-4167-2025, https://doi.org/10.5194/acp-25-4167-2025, 2025
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The area-wide radar-based distinction between riming and aggregation is crucial for model microphysics and data assimilation. This study introduces a discrimination algorithm based on polarimetric radar networks only. Exploiting the unique opportunity to link fall velocities from Doppler spectra to polarimetric variables in an operational setting enables us to set up and evaluate a well-performing machine learning algorithm.
Cristina Gil-Díaz, Michäel Sicard, Odran Sourdeval, Athulya Saiprakash, Constantino Muñoz-Porcar, Adolfo Comerón, Alejandro Rodríguez-Gómez, and Daniel Camilo Fortunato dos Santos Oliveira
Atmos. Chem. Phys., 25, 3445–3464, https://doi.org/10.5194/acp-25-3445-2025, https://doi.org/10.5194/acp-25-3445-2025, 2025
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This study presents a comprehensive analysis of optical scattering properties and direct radiative effects of cirrus clouds based on 4 years of continuous ground-based lidar measurements with the Barcelona MPLNET lidar. A novel approach of the self-consistent scattering model for cirrus clouds is presented to determine their optical scattering properties at different wavelengths, and their direct radiative effects are calculated with the discrete ordinates method embedded in the ARTDECO package.
Tom Goren, Goutam Choudhury, Jan Kretzschmar, and Isabel McCoy
Atmos. Chem. Phys., 25, 3413–3423, https://doi.org/10.5194/acp-25-3413-2025, https://doi.org/10.5194/acp-25-3413-2025, 2025
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Many studies have identified an inverted-V relationship between the liquid water path (LWP) and droplet concentration (Nd), where LWP increases and then decreases with Nd. Using satellite observations and meteorological data, we demonstrate that the inverted V primarily reflects co-variability between LWP and Nd. We suggest taking a holistic approach that considers this co-variability when assessing the climatological sensitivity of LWP to anthropogenic aerosols.
Cristofer Jimenez, Albert Ansmann, Kevin Ohneiser, Hannes Griesche, Ronny Engelmann, Martin Radenz, Julian Hofer, Dietrich Althausen, Daniel Alexander Knopf, Sandro Dahlke, Johannes Bühl, Holger Baars, Patric Seifert, and Ulla Wandinger
EGUsphere, https://doi.org/10.5194/egusphere-2025-967, https://doi.org/10.5194/egusphere-2025-967, 2025
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Using advanced remote sensing on the icebreaker Polarstern, we studied mixed-phase clouds (MPCs) in the central Arctic during the 2019–2020 MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) campaign. For the first time, lidar and radar techniques tracked the year-round evolution of liquid and ice phases in MPCs. The study provides cloud statistics and explores key processes driving cloud longevity, offering new insights into Arctic cloud formation and persistence.
Chris J. Wright, Joel A. Thornton, Lyatt Jaeglé, Yang Cao, Yannian Zhu, Jihu Liu, Randall Jones II, Robert Holzworth, Daniel Rosenfeld, Robert Wood, Peter Blossey, and Daehyun Kim
Atmos. Chem. Phys., 25, 2937–2946, https://doi.org/10.5194/acp-25-2937-2025, https://doi.org/10.5194/acp-25-2937-2025, 2025
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Aerosol particles influence clouds, which exert a large forcing on solar radiation and freshwater. To better understand the mechanisms by which aerosol influences thunderstorms, we look at the two busiest shipping lanes in the world, where recent regulations have reduced sulfur emissions by nearly an order of magnitude. We find that the reduction in emissions has been accompanied by a dramatic decrease in both lightning and the number of droplets in clouds over the shipping lanes.
Andrea Kolínská, Ivana Kolmašová, Eric Defer, Ondřej Santolík, and Stéphane Pédeboy
Atmos. Chem. Phys., 25, 1791–1803, https://doi.org/10.5194/acp-25-1791-2025, https://doi.org/10.5194/acp-25-1791-2025, 2025
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We contribute to understanding differences in lightning flashes of opposite polarity by explaining distinct in-cloud processes after return strokes. Using data from multiple sensors, including individual Lightning Mapping Array stations, we reveal that positive flashes sustain strong high-frequency radiation due to the recharging of their in-cloud leader; this is in contrast to negative flashes, for which this activity declines rapidly.
Sarah Brüning and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2025-374, https://doi.org/10.5194/egusphere-2025-374, 2025
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This study analyses the temporal variability and life-cycle of spatially organised convective clouds, frequently associated with severe weather. We derive the data from a machine learning-based 3D extrapolation of 2D satellite data. The results highlight the impact of convective organisation on horizontal and vertical cloud properties and a prolonged cloud life-cycle. Overall, our findings emphasise a more intense activity over land but enhanced seasonal changes over the ocean.
Sarah Brüning and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2025-376, https://doi.org/10.5194/egusphere-2025-376, 2025
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The connection between convective cloud organisation and severe weather demands a robust characterisation of hazardous clouds. This study sets on to investigate spatio-temporal patterns and regional hotspots of convective organisation using machine learning-based 3D data and combining different organisation indices. While limitations arise due to overlapping effects of isolated and clustered convection, we emphasise the impact of a surface-specific seasonality that depends on the hemisphere.
Mengyuan Wang, Min Min, Jun Li, Han Lin, Yongen Liang, Binlong Chen, Zhigang Yao, Na Xu, and Miao Zhang
Atmos. Chem. Phys., 24, 14239–14256, https://doi.org/10.5194/acp-24-14239-2024, https://doi.org/10.5194/acp-24-14239-2024, 2024
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Although machine learning technology is advanced in the field of satellite remote sensing, the physical inversion algorithm based on cloud base height can better capture the daily variation in the characteristics of the cloud base.
Zhenquan Wang and Jian Yuan
Atmos. Chem. Phys., 24, 13811–13831, https://doi.org/10.5194/acp-24-13811-2024, https://doi.org/10.5194/acp-24-13811-2024, 2024
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Tropical convection organizations are normally connected complexes of many convective activities. In this work, a novel variable-brightness-temperature segment tracking algorithm is established to partition the complex convective organizations into structural components of single cold cores for tracking separately. The duration, precipitation and anvil amount of the tracked organization segments have strong loglinear relationships with brightness temperature structures.
David L. Mitchell, Anne Emilie Garnier, and Sarah Woods
EGUsphere, https://doi.org/10.5194/egusphere-2024-3790, https://doi.org/10.5194/egusphere-2024-3790, 2024
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Motivated by the need to better understand the physics of cirrus clouds, a satellite retrieval for cirrus cloud ice water content, ice particle number concentration and effective size was developed by exploiting relationships between cirrus cloud measurements made during field campaigns and cloud radiative properties measured by satellite. These retrievals tested favorably when compared against corresponding aircraft measurements and were found to depend on the visual opacity of the cloud.
David L. Mitchell and Anne Garnier
EGUsphere, https://doi.org/10.5194/egusphere-2024-3814, https://doi.org/10.5194/egusphere-2024-3814, 2024
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Arguably the greatest knowledge gap in cirrus cloud research is the relative roles of homogeneous and heterogeneous ice nucleation in cirrus cloud formation. Since this depends on temperature, latitude, season, and topography, a satellite remote sensing method was developed to measure cirrus cloud properties. It was found that cirrus clouds strongly affected by homogeneous ice nucleation may account for over half of the overall cirrus cloud radiative effect during winter outside the tropics.
Anna Tippett, Edward Gryspeerdt, Peter Manshausen, Philip Stier, and Tristan W. P. Smith
Atmos. Chem. Phys., 24, 13269–13283, https://doi.org/10.5194/acp-24-13269-2024, https://doi.org/10.5194/acp-24-13269-2024, 2024
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Ship emissions can form artificially brightened clouds, known as ship tracks, and provide us with an opportunity to investigate how aerosols interact with clouds. Previous studies that used ship tracks suggest that clouds can experience large increases in the amount of water (LWP) from aerosols. Here, we show that there is a bias in previous research and that, when we account for this bias, the LWP response to aerosols is much weaker than previously reported.
Rebecca J. Murray-Watson and Edward Gryspeerdt
Atmos. Chem. Phys., 24, 11115–11132, https://doi.org/10.5194/acp-24-11115-2024, https://doi.org/10.5194/acp-24-11115-2024, 2024
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The formation of mixed-phase clouds during marine cold-air outbreaks is not well understood. Our study, using satellite data and Lagrangian trajectories, reveals that the occurrence of these clouds depends on both time and temperature, influenced partly by the presence of biological ice-nucleating particles. This highlights the importance of comprehending local aerosol dynamics for precise modelling of cloud-phase transitions in the Arctic.
Yuxin Zhao, Jiming Li, Deyu Wen, Yarong Li, Yuan Wang, and Jianping Huang
Atmos. Chem. Phys., 24, 9435–9457, https://doi.org/10.5194/acp-24-9435-2024, https://doi.org/10.5194/acp-24-9435-2024, 2024
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This study identifies deep convection systems (DCSs), including deep convection cores and anvils, over the Tibetan Plateau (TP) and tropical Indian Ocean (TO). The DCSs over the TP are less frequent, showing narrower and thinner cores and anvils compared to those over the TO. TP DCSs show a stronger longwave cloud radiative effect at the surface and in the low-level atmosphere. Distinct aerosol–cloud–precipitation interaction is found in TP DCSs, probably due to the cold cloud bases.
Grégory V. Cesana, Olivia Pierpaoli, Matteo Ottaviani, Linh Vu, Zhonghai Jin, and Israel Silber
Atmos. Chem. Phys., 24, 7899–7909, https://doi.org/10.5194/acp-24-7899-2024, https://doi.org/10.5194/acp-24-7899-2024, 2024
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Better characterizing the relationship between sea ice and clouds is key to understanding Arctic climate because clouds and sea ice affect surface radiation and modulate Arctic surface warming. Our results indicate that Arctic liquid clouds robustly increase in response to sea ice decrease. This increase has a cooling effect on the surface because more solar radiation is reflected back to space, and it should contribute to dampening future Arctic surface warming.
Ziming Wang, Husi Letu, Huazhe Shang, and Luca Bugliaro
Atmos. Chem. Phys., 24, 7559–7574, https://doi.org/10.5194/acp-24-7559-2024, https://doi.org/10.5194/acp-24-7559-2024, 2024
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The supercooled liquid fraction (SLF) in mixed-phase clouds is retrieved for the first time using passive geostationary satellite observations based on differences in liquid droplet and ice particle radiative properties. The retrieved results are comparable to global distributions observed by active instruments, and the feasibility of the retrieval method to analyze the observed trends of the SLF has been validated.
Barbara Dietel, Odran Sourdeval, and Corinna Hoose
Atmos. Chem. Phys., 24, 7359–7383, https://doi.org/10.5194/acp-24-7359-2024, https://doi.org/10.5194/acp-24-7359-2024, 2024
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Uncertainty with respect to cloud phases over the Southern Ocean and Arctic marine regions leads to large uncertainties in the radiation budget of weather and climate models. This study investigates the phases of low-base and mid-base clouds using satellite-based remote sensing data. A comprehensive analysis of the correlation of cloud phase with various parameters, such as temperature, aerosols, sea ice, vertical and horizontal cloud extent, and cloud radiative effect, is presented.
Ryan Eastman, Isabel L. McCoy, Hauke Schulz, and Robert Wood
Atmos. Chem. Phys., 24, 6613–6634, https://doi.org/10.5194/acp-24-6613-2024, https://doi.org/10.5194/acp-24-6613-2024, 2024
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Cloud types are determined using machine learning image classifiers applied to satellite imagery for 1 year in the North Atlantic. This survey of these cloud types shows that the climate impact of a cloud scene is, in part, a function of cloud type. Each type displays a different mix of thick and thin cloud cover, with the fraction of thin cloud cover having the strongest impact on the clouds' radiative effect. Future studies must account for differing properties and processes among cloud types.
Georgios Dekoutsidis, Martin Wirth, and Silke Groß
Atmos. Chem. Phys., 24, 5971–5987, https://doi.org/10.5194/acp-24-5971-2024, https://doi.org/10.5194/acp-24-5971-2024, 2024
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For decades the earth's temperature has been rising. The Arctic regions are warming faster. Cirrus clouds can contribute to this phenomenon. During warm-air intrusions, air masses are transported into the Arctic from the mid-latitudes. The HALO-(AC)3 campaign took place to measure cirrus during intrusion events and under normal conditions. We study the two cloud types based on these measurements and find differences in their geometry, relative humidity distribution and vertical structure.
Huige Di and Yun Yuan
Atmos. Chem. Phys., 24, 5783–5801, https://doi.org/10.5194/acp-24-5783-2024, https://doi.org/10.5194/acp-24-5783-2024, 2024
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We observed the seeder–feeder process among double-layer clouds using a cloud radar and microwave radiometer. By defining the parameters of the seeding depth and seeding time of the upper cloud affecting the lower cloud, we find that the cloud particle terminal velocity is significantly enhanced during the seeder–feeder period, and the lower the height and thinner the thickness of the height difference between double-layer clouds, the lower the height and thicker the thickness of seeding depth.
Kristofer S. Tuftedal, Bernat Puigdomènech Treserras, Mariko Oue, and Pavlos Kollias
Atmos. Chem. Phys., 24, 5637–5657, https://doi.org/10.5194/acp-24-5637-2024, https://doi.org/10.5194/acp-24-5637-2024, 2024
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This study analyzed coastal convective cells from June through September 2018–2021. The cells were classified and their lifecycles were analyzed to better understand their characteristics. Features such as convective-core growth, for example, are shown. The study found differences in the initiation location of shallow convection and in the aerosol loading in deep convective environments. This work provides a foundation for future analyses of convection or other tracked events elsewhere.
Michie Vianca De Vera, Larry Di Girolamo, Guangyu Zhao, Robert M. Rauber, Stephen W. Nesbitt, and Greg M. McFarquhar
Atmos. Chem. Phys., 24, 5603–5623, https://doi.org/10.5194/acp-24-5603-2024, https://doi.org/10.5194/acp-24-5603-2024, 2024
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Tropical oceanic low clouds remain a dominant source of uncertainty in cloud feedback in climate models due to their macrophysical properties (fraction, size, height, shape, distribution) being misrepresented. High-resolution satellite imagery over the Philippine oceans is used here to characterize cumulus macrophysical properties and their relationship to meteorological variables. Such information can act as a benchmark for cloud models and can improve low-cloud generation in climate models.
William K. Jones, Martin Stengel, and Philip Stier
Atmos. Chem. Phys., 24, 5165–5180, https://doi.org/10.5194/acp-24-5165-2024, https://doi.org/10.5194/acp-24-5165-2024, 2024
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Storm clouds cover large areas of the tropics. These clouds both reflect incoming sunlight and trap heat from the atmosphere below, regulating the temperature of the tropics. Over land, storm clouds occur in the late afternoon and evening and so exist both during the daytime and at night. Changes in this timing could upset the balance of the respective cooling and heating effects of these clouds. We find that isolated storms have a larger effect on this balance than their small size suggests.
Shaoyue Qiu, Xue Zheng, David Painemal, Christopher R. Terai, and Xiaoli Zhou
Atmos. Chem. Phys., 24, 2913–2935, https://doi.org/10.5194/acp-24-2913-2024, https://doi.org/10.5194/acp-24-2913-2024, 2024
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The aerosol indirect effect (AIE) depends on cloud states, which exhibit significant diurnal variations in the northeastern Atlantic. Yet the AIE diurnal cycle remains poorly understood. Using satellite retrievals, we find a pronounced “U-shaped” diurnal variation in the AIE, which is contributed to by the transition of cloud states combined with the lagged cloud responses. This suggests that polar-orbiting satellites with overpass times at noon underestimate daytime mean values of the AIE.
Irene Bartolomé García, Odran Sourdeval, Reinhold Spang, and Martina Krämer
Atmos. Chem. Phys., 24, 1699–1716, https://doi.org/10.5194/acp-24-1699-2024, https://doi.org/10.5194/acp-24-1699-2024, 2024
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How many ice crystals of each size are in a cloud is a key parameter for the retrieval of cloud properties. The distribution of ice crystals is obtained from in situ measurements and used to create parameterizations that can be used when analyzing the remote-sensing data. Current parameterizations are based on data sets that do not include reliable measurements of small crystals, but in our study we use a data set that includes very small ice crystals to improve these parameterizations.
Wenyue Wang, Klemens Hocke, Leonardo Nania, Alberto Cazorla, Gloria Titos, Renaud Matthey, Lucas Alados-Arboledas, Agustín Millares, and Francisco Navas-Guzmán
Atmos. Chem. Phys., 24, 1571–1585, https://doi.org/10.5194/acp-24-1571-2024, https://doi.org/10.5194/acp-24-1571-2024, 2024
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The south-central interior of Andalusia experiences complex precipitation patterns as a result of the semi-arid Mediterranean climate and the influence of Saharan dust. This study monitored the inter-relations between aerosols, clouds, meteorological variables, and precipitation systems using ground-based remote sensing and in situ instruments.
Francisco Lang, Steven T. Siems, Yi Huang, Tahereh Alinejadtabrizi, and Luis Ackermann
Atmos. Chem. Phys., 24, 1451–1466, https://doi.org/10.5194/acp-24-1451-2024, https://doi.org/10.5194/acp-24-1451-2024, 2024
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Marine low-level clouds play a crucial role in the Earth's energy balance, trapping heat from the surface and reflecting sunlight back into space. These clouds are distinguishable by their large-scale spatial structures, primarily characterized as hexagonal patterns with either filled (closed) or empty (open) cells. Utilizing satellite observations, these two cloud type patterns have been categorized over the Southern Ocean and North Pacific Ocean through a pattern recognition program.
Julian Hofer, Patric Seifert, J. Ben Liley, Martin Radenz, Osamu Uchino, Isamu Morino, Tetsu Sakai, Tomohiro Nagai, and Albert Ansmann
Atmos. Chem. Phys., 24, 1265–1280, https://doi.org/10.5194/acp-24-1265-2024, https://doi.org/10.5194/acp-24-1265-2024, 2024
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An 11-year dataset of polarization lidar observations from Lauder, New Zealand / Aotearoa, was used to distinguish the thermodynamic phase of natural clouds. The cloud dataset was separated to assess the impact of air mass origin on the frequency of heterogeneous ice formation. Ice formation efficiency in clouds above Lauder was found to be lower than in the polluted Northern Hemisphere midlatitudes but higher than in very clean and pristine environments, such as Punta Arenas in southern Chile.
Hannes Jascha Griesche, Carola Barrientos-Velasco, Hartwig Deneke, Anja Hünerbein, Patric Seifert, and Andreas Macke
Atmos. Chem. Phys., 24, 597–612, https://doi.org/10.5194/acp-24-597-2024, https://doi.org/10.5194/acp-24-597-2024, 2024
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The Arctic is strongly affected by climate change and the role of clouds therein is not yet completely understood. Measurements from the Arctic expedition PS106 were used to simulate radiative fluxes with and without clouds at very low altitudes (below 165 m), and their radiative effect was calculated to be 54 Wm-2. The low heights of these clouds make them hard to observe. This study shows the importance of accurate measurements and simulations of clouds and gives suggestions for improvements.
Thomas D. DeWitt, Timothy J. Garrett, Karlie N. Rees, Corey Bois, Steven K. Krueger, and Nicolas Ferlay
Atmos. Chem. Phys., 24, 109–122, https://doi.org/10.5194/acp-24-109-2024, https://doi.org/10.5194/acp-24-109-2024, 2024
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Viewed from space, a defining feature of Earth's atmosphere is the wide spectrum of cloud sizes. A recent study predicted the distribution of cloud sizes, and this paper compares the prediction to observations. Although there is nuance in viewing perspective, we find robust agreement with theory across different climatological conditions, including land–ocean contrasts, time of year, or latitude, suggesting a minor role for Coriolis forces, aerosol loading, or surface temperature.
Marcus Klingebiel, André Ehrlich, Elena Ruiz-Donoso, Nils Risse, Imke Schirmacher, Evelyn Jäkel, Michael Schäfer, Kevin Wolf, Mario Mech, Manuel Moser, Christiane Voigt, and Manfred Wendisch
Atmos. Chem. Phys., 23, 15289–15304, https://doi.org/10.5194/acp-23-15289-2023, https://doi.org/10.5194/acp-23-15289-2023, 2023
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In this study we explain how we use aircraft measurements from two Arctic research campaigns to identify cloud properties (like droplet size) over sea-ice and ice-free ocean. To make sure that our measurements make sense, we compare them with other observations. Our results show, e.g., larger cloud droplets in early summer than in spring. Moreover, the cloud droplets are also larger over ice-free ocean than compared to sea ice. In the future, our data can be used to improve climate models.
Pablo Saavedra Garfias, Heike Kalesse-Los, Luisa von Albedyll, Hannes Griesche, and Gunnar Spreen
Atmos. Chem. Phys., 23, 14521–14546, https://doi.org/10.5194/acp-23-14521-2023, https://doi.org/10.5194/acp-23-14521-2023, 2023
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An important Arctic climate process is the release of heat fluxes from sea ice openings to the atmosphere that influence the clouds. The characterization of this process is the objective of this study. Using synergistic observations from the MOSAiC expedition, we found that single-layer cloud properties show significant differences when clouds are coupled or decoupled to the water vapour transport which is used as physical link between the upwind sea ice openings and the cloud under observation.
Matthew D. Lebsock and Mikael Witte
Atmos. Chem. Phys., 23, 14293–14305, https://doi.org/10.5194/acp-23-14293-2023, https://doi.org/10.5194/acp-23-14293-2023, 2023
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This paper evaluates measurements of cloud drop size distributions made from airplanes. We find that as the number of cloud drops increases the distribution of the cloud drop sizes narrows. The data are used to develop a simple equation that relates the drop number to the width of the drop sizes. We then use this equation to demonstrate that existing approaches to observe the drop number from satellites contain errors that can be corrected by including the new relationship.
George Horner and Edward Gryspeerdt
Atmos. Chem. Phys., 23, 14239–14253, https://doi.org/10.5194/acp-23-14239-2023, https://doi.org/10.5194/acp-23-14239-2023, 2023
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Tropical deep convective clouds, and the thin cirrus (ice) clouds that flow out from them, are important for modulating the energy budget of the tropical atmosphere. This work uses a new method to track the evolution of the properties of these clouds across their entire lifetimes. We find these clouds cool the atmosphere in the first 6 h before switching to a warming regime after the deep convective core has dissipated, which is sustained beyond 120 h from the initial convective event.
Rodanthi-Elisavet Mamouri, Albert Ansmann, Kevin Ohneiser, Daniel A. Knopf, Argyro Nisantzi, Johannes Bühl, Ronny Engelmann, Annett Skupin, Patric Seifert, Holger Baars, Dragos Ene, Ulla Wandinger, and Diofantos Hadjimitsis
Atmos. Chem. Phys., 23, 14097–14114, https://doi.org/10.5194/acp-23-14097-2023, https://doi.org/10.5194/acp-23-14097-2023, 2023
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For the first time, rather clear evidence is found that wildfire smoke particles can trigger strong cirrus formation. This finding is of importance because intensive and large wildfires may occur increasingly often in the future as climate change proceeds. Based on lidar observations in Cyprus in autumn 2020, we provide detailed insight into the cirrus formation at the tropopause in the presence of aged wildfire smoke (here, 8–9 day old Californian wildfire smoke).
Peter Manshausen, Duncan Watson-Parris, Matthew W. Christensen, Jukka-Pekka Jalkanen, and Philip Stier
Atmos. Chem. Phys., 23, 12545–12555, https://doi.org/10.5194/acp-23-12545-2023, https://doi.org/10.5194/acp-23-12545-2023, 2023
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Aerosol from burning fuel changes cloud properties, e.g., the number of droplets and the content of water. Here, we study how clouds respond to different amounts of shipping aerosol. Droplet numbers increase linearly with increasing aerosol over a broad range until they stop increasing, while the amount of liquid water always increases, independently of emission amount. These changes in cloud properties can make them reflect more or less sunlight, which is important for the earth's climate.
Hendrik Andersen, Jan Cermak, Alyson Douglas, Timothy A. Myers, Peer Nowack, Philip Stier, Casey J. Wall, and Sarah Wilson Kemsley
Atmos. Chem. Phys., 23, 10775–10794, https://doi.org/10.5194/acp-23-10775-2023, https://doi.org/10.5194/acp-23-10775-2023, 2023
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This study uses an observation-based cloud-controlling factor framework to study near-global sensitivities of cloud radiative effects to a large number of meteorological and aerosol controls. We present near-global sensitivity patterns to selected thermodynamic, dynamic, and aerosol factors and discuss the physical mechanisms underlying the derived sensitivities. Our study hopes to guide future analyses aimed at constraining cloud feedbacks and aerosol–cloud interactions.
Anne-Claire Billault-Roux, Paraskevi Georgakaki, Josué Gehring, Louis Jaffeux, Alfons Schwarzenboeck, Pierre Coutris, Athanasios Nenes, and Alexis Berne
Atmos. Chem. Phys., 23, 10207–10234, https://doi.org/10.5194/acp-23-10207-2023, https://doi.org/10.5194/acp-23-10207-2023, 2023
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Secondary ice production plays a key role in clouds and precipitation. In this study, we analyze radar measurements from a snowfall event in the Jura Mountains. Complex signatures are observed, which reveal that ice crystals were formed through various processes. An analysis of multi-sensor data suggests that distinct ice multiplication processes were taking place. Both the methods used and the insights gained through this case study contribute to a better understanding of snowfall microphysics.
Rebecca J. Murray-Watson, Edward Gryspeerdt, and Tom Goren
Atmos. Chem. Phys., 23, 9365–9383, https://doi.org/10.5194/acp-23-9365-2023, https://doi.org/10.5194/acp-23-9365-2023, 2023
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Clouds formed in Arctic marine cold air outbreaks undergo a distinct evolution, but the factors controlling their transition from high-coverage to broken cloud fields are poorly understood. We use satellite and reanalysis data to study how these clouds develop in time and the different influences on their evolution. The aerosol concentration is correlated with cloud break-up; more aerosol is linked to prolonged coverage and a stronger cooling effect, with implications for a more polluted Arctic.
Michael S. Diamond
Atmos. Chem. Phys., 23, 8259–8269, https://doi.org/10.5194/acp-23-8259-2023, https://doi.org/10.5194/acp-23-8259-2023, 2023
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Fuel sulfur regulations were implemented for ships in 2020 to improve air quality but may also accelerate global warming. We use spatial statistics and satellite retrievals to detect changes in the size of cloud droplets and find evidence for a resulting decrease in cloud brightness within a major shipping corridor after the sulfur limits went into effect. Our results confirm both that the regulations are being followed and that they are having a warming influence via their effect on clouds.
Hao Luo, Johannes Quaas, and Yong Han
Atmos. Chem. Phys., 23, 8169–8186, https://doi.org/10.5194/acp-23-8169-2023, https://doi.org/10.5194/acp-23-8169-2023, 2023
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Clouds exhibit a wide range of vertical structures with varying microphysical and radiative properties. We show a global survey of spatial distribution, vertical extent and radiative effect of various classified cloud vertical structures using joint satellite observations from the new CCCM datasets during 2007–2010. Moreover, the long-term trends in CVSs are investigated based on different CMIP6 future scenarios to capture the cloud variations with different, increasing anthropogenic forcings.
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Executive editor
The tropical tropopause region (14-18km altitude) plays an important role in the climate system, but the technical difficulties of making measurements in this region are severe. This paper reports observations of very thin tropical tropopause cirrus clouds made using a new lidar instrument carried on long-duration balloon flights, lasting several weeks and travelling about 20000km, from the Indian Ocean to the Central Pacific. The sensitivity of the new instrument reveals that clouds are much more frequent in this part of the atmosphere than had been identified previously. The quantitative significance for the large-scale climate system, e.g. for the radiation balance, is yet to be assessed, but it is clear that these observations will be a valuable resource for scientists studying this truly remote part of the atmosphere.
The tropical tropopause region (14-18km altitude) plays an important role in the climate system,...
Short summary
Upper tropical clouds have a strong impact on Earth's climate but are challenging to observe. We report the first long-duration observations of tropical clouds from lidars flying on board stratospheric balloons. Comparisons with spaceborne observations reveal the enhanced sensitivity of balloon-borne lidar to optically thin cirrus. These clouds, which have a significant coverage and lie in the uppermost troposphere, are linked with the dehydration of air masses on their way to the stratosphere.
Upper tropical clouds have a strong impact on Earth's climate but are challenging to observe. We...
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