Articles | Volume 21, issue 16
https://doi.org/10.5194/acp-21-12261-2021
© Author(s) 2021. 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-21-12261-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
16 Aug 2021
Research article |
| 16 Aug 2021
| 16 Aug 2021
Deciphering organization of GOES-16 green cumulus through the empirical orthogonal function (EOF) lens
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
Mickaël D. Chekroun
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
Orit Altaratz
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
Related authors
Tom Dror, J. Michel Flores, Orit Altaratz, Guy Dagan, Zev Levin, Assaf Vardi, and Ilan Koren
Atmos. Chem. Phys., 20, 15297–15306, https://doi.org/10.5194/acp-20-15297-2020, https://doi.org/10.5194/acp-20-15297-2020, 2020
Short summary
Short summary
We used in situ aerosol measurements over the Atlantic, Caribbean, and Pacific to initialize a cloud model and study the impact of aerosol concentration and sizes on warm clouds. We show that high aerosol concentration increases cloud mass and reduces surface rain when giant particles (diameter > 9 µm) are present. The large aerosols changed the timing and magnitude of internal cloud processes and resulted in an enhanced evaporation below cloud base and dramatically reduced surface rain.
Huan Liu, Ilan Koren, Orit Altaratz, and Shutian Mu
EGUsphere, https://doi.org/10.5194/egusphere-2025-2574, https://doi.org/10.5194/egusphere-2025-2574, 2025
Short summary
Short summary
Clouds play a crucial role in Earth's climate by reflecting sunlight and trapping heat. Understanding how clouds respond to global warming (cloud feedback) is essential for climate change. However, the natural climate variability, like ENSO, can distort these estimates. Relying on long-term reanalysis data and simulations, this study finds that ENSO with a typical periodicity of 2–7 years can introduce a significant bias on cloud feedback estimates on even decadal to century time scales.
Manuel Santos Gutiérrez, Mickaël David Chekroun, and Ilan Koren
EGUsphere, https://doi.org/10.48550/arXiv.2405.11545, https://doi.org/10.48550/arXiv.2405.11545, 2024
Preprint withdrawn
Short summary
Short summary
This letter explores a novel approach for the formation of cloud droplets in rising adiabatic air parcels. Our approach combines microphysical equations accounting for moisture, updrafts and concentration of aerosols. Our analysis reveals three regimes: A) Low moisture and high concentration can hinder activation; B) Droplets can activate and stabilize above critical sizes, and C) sparse clouds can have droplets exhibiting activation and deactivation cycles.
Huan Liu, Ilan Koren, Orit Altaratz, and Mickaël D. Chekroun
Atmos. Chem. Phys., 23, 6559–6569, https://doi.org/10.5194/acp-23-6559-2023, https://doi.org/10.5194/acp-23-6559-2023, 2023
Short summary
Short summary
Clouds' responses to global warming contribute the largest uncertainty in climate prediction. Here, we analyze 42 years of global cloud cover in reanalysis data and show a decreasing trend over most continents and an increasing trend over the tropical and subtropical oceans. A reduction in near-surface relative humidity can explain the decreasing trend in cloud cover over land. Our results suggest potential stress on the terrestrial water cycle, associated with global warming.
Elisa T. Sena, Ilan Koren, Orit Altaratz, and Alexander B. Kostinski
Atmos. Chem. Phys., 22, 16111–16122, https://doi.org/10.5194/acp-22-16111-2022, https://doi.org/10.5194/acp-22-16111-2022, 2022
Short summary
Short summary
We used record-breaking statistics together with spatial information to create record-breaking SST maps. The maps reveal warming patterns in the overwhelming majority of the ocean and coherent islands of cooling, where low records occur more frequently than high ones. Some of these cooling spots are well known; however, a surprising elliptical area in the Southern Ocean is observed as well. Similar analyses can be performed on other key climatological variables to explore their trend patterns.
Eshkol Eytan, Ilan Koren, Orit Altaratz, Mark Pinsky, and Alexander Khain
Atmos. Chem. Phys., 21, 16203–16217, https://doi.org/10.5194/acp-21-16203-2021, https://doi.org/10.5194/acp-21-16203-2021, 2021
Short summary
Short summary
Describing cloud mixing processes is among the most challenging fronts in cloud physics. Therefore, the adiabatic fraction (AF) that serves as a mixing measure is a valuable metric. We use high-resolution (10 m) simulations of single clouds with a passive tracer to test the skill of different methods used to derive AF. We highlight a method that is insensitive to the available cloud samples and allows considering microphysical effects on AF estimations in different environmental conditions.
Tom Dror, J. Michel Flores, Orit Altaratz, Guy Dagan, Zev Levin, Assaf Vardi, and Ilan Koren
Atmos. Chem. Phys., 20, 15297–15306, https://doi.org/10.5194/acp-20-15297-2020, https://doi.org/10.5194/acp-20-15297-2020, 2020
Short summary
Short summary
We used in situ aerosol measurements over the Atlantic, Caribbean, and Pacific to initialize a cloud model and study the impact of aerosol concentration and sizes on warm clouds. We show that high aerosol concentration increases cloud mass and reduces surface rain when giant particles (diameter > 9 µm) are present. The large aerosols changed the timing and magnitude of internal cloud processes and resulted in an enhanced evaporation below cloud base and dramatically reduced surface rain.
Reuven H. Heiblum, Lital Pinto, Orit Altaratz, Guy Dagan, and Ilan Koren
Atmos. Chem. Phys., 19, 10717–10738, https://doi.org/10.5194/acp-19-10717-2019, https://doi.org/10.5194/acp-19-10717-2019, 2019
Short summary
Short summary
It is useful to divide a cloud into two regions: core and margin. Three parameters used to define a core are compared: buoyancy (B), relative humidity (RH), and vertical velocity (W). Using theoretical arguments and simulations, we show that during most of a cloud's lifetime, the cores are subsets of one another: Bcore ⊆ RHcore ⊆ Wcore. Moreover, the core–shell cloud model applies to all core definitions. Our findings can serve as a benchmark in the partition the core and margin.
Reuven H. Heiblum, Lital Pinto, Orit Altaratz, Guy Dagan, and Ilan Koren
Atmos. Chem. Phys., 19, 10739–10755, https://doi.org/10.5194/acp-19-10739-2019, https://doi.org/10.5194/acp-19-10739-2019, 2019
Short summary
Short summary
The effects of aerosol concentration on a cloud's partition to core and margin are examined. The main finding from Part I (i.e. Bcore ⊆ RHcore ⊆ Wcore) is seen for all aerosol concentrations. Clouds can produce positive buoyancy due to both saturated updrafts or unsaturated downdrafts; the latter are dependent on low aerosol concentrations. We show that a cloud's mass is mainly dependent on core processes (condensation), while its volume is mainly dependent on margin processes (evaporation).
Stefano Pierini, Mickaël D. Chekroun, and Michael Ghil
Nonlin. Processes Geophys., 25, 671–692, https://doi.org/10.5194/npg-25-671-2018, https://doi.org/10.5194/npg-25-671-2018, 2018
Short summary
Short summary
A four-dimensional nonlinear spectral ocean model is used to study the transition to chaos induced by periodic forcing in systems that are nonchaotic in the autonomous limit. The analysis makes use of ensemble simulations and of the system's pullback attractors. A new diagnostic method characterizes the transition to chaos: this is found to occur abruptly at a critical value and begins with the intermittent emergence of periodic oscillations with distinct phases.
Guy Dagan, Ilan Koren, and Orit Altaratz
Atmos. Chem. Phys., 18, 6761–6769, https://doi.org/10.5194/acp-18-6761-2018, https://doi.org/10.5194/acp-18-6761-2018, 2018
Short summary
Short summary
In this paper we distill the problem of aerosol–cloud interactions to an interplay between the system's two characteristic vertical velocities, i.e., the air vertical velocity and the collective droplets fall velocity. We show using theoretical considerations and cloud-resolving models that the relations between the two velocities are extremely sensitive to the cloud field's thermodynamics and microphysical properties.
Niklas Boers, Mickael D. Chekroun, Honghu Liu, Dmitri Kondrashov, Denis-Didier Rousseau, Anders Svensson, Matthias Bigler, and Michael Ghil
Earth Syst. Dynam., 8, 1171–1190, https://doi.org/10.5194/esd-8-1171-2017, https://doi.org/10.5194/esd-8-1171-2017, 2017
Short summary
Short summary
We use a Bayesian approach for inferring inverse, stochastic–dynamic models from northern Greenland (NGRIP) oxygen and dust records of subdecadal resolution for the interval 59 to 22 ka b2k. Our model reproduces the statistical and dynamical characteristics of the records, including the Dansgaard–Oeschger variability, with no need for external forcing. The crucial ingredients are cubic drift terms, nonlinear coupling terms between the oxygen and dust time series, and non-Markovian contributions.
Yevgeny Derimian, Marie Choël, Yinon Rudich, Karine Deboudt, Oleg Dubovik, Alexander Laskin, Michel Legrand, Bahaiddin Damiri, Ilan Koren, Florin Unga, Myriam Moreau, Meinrat O. Andreae, and Arnon Karnieli
Atmos. Chem. Phys., 17, 11331–11353, https://doi.org/10.5194/acp-17-11331-2017, https://doi.org/10.5194/acp-17-11331-2017, 2017
Short summary
Short summary
We present influence of daily occurrence of the sea breeze flow from the Mediterranean Sea on physicochemical and optical properties of atmospheric aerosol deep inland in the Negev Desert of Israel. Sampled airborne dust was found be internally mixed with sea-salt particles and reacted with anthropogenic pollution, which makes the dust highly hygroscopic and a liquid coating of particles appears. These physicochemical transformations are associated with a change in aerosol radiative properties.
Qian Chen, Ilan Koren, Orit Altaratz, Reuven H. Heiblum, Guy Dagan, and Lital Pinto
Atmos. Chem. Phys., 17, 9585–9598, https://doi.org/10.5194/acp-17-9585-2017, https://doi.org/10.5194/acp-17-9585-2017, 2017
Guy Dagan, Ilan Koren, Orit Altaratz, and Reuven H. Heiblum
Atmos. Chem. Phys., 17, 7435–7444, https://doi.org/10.5194/acp-17-7435-2017, https://doi.org/10.5194/acp-17-7435-2017, 2017
Short summary
Short summary
Large eddy simulations with bin microphysics are used to study cloud fields' sensitivity to changes in aerosol loading and the time evolution of this response. We show that the mean field properties change with a non-monotonic trend, with an optimum aerosol concentration for which the field reaches its maximal water mass or rain yield. The evolution of the mean thermodynamic properties is studied and shown to cause the migration of the optimal aerosol concentration toward higher values.
Yaniv Tubul, Ilan Koren, Orit Altaratz, and Reuven H. Heiblum
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2017-121, https://doi.org/10.5194/amt-2017-121, 2017
Revised manuscript not accepted
Chandan Sarangi, Sachchida Nand Tripathi, Vijay P. Kanawade, Ilan Koren, and D. Sivanand Pai
Atmos. Chem. Phys., 17, 5185–5204, https://doi.org/10.5194/acp-17-5185-2017, https://doi.org/10.5194/acp-17-5185-2017, 2017
Short summary
Short summary
Aerosol-induced perturbations in cloud systems and rainfall are very uncertain. This study provides observational evidence of a robust positive association between aerosol–cloud–rainfall properties over the Indian summer monsoon region. Observed and modeled aerosol–cloud microphysical changes illustrate that cloud invigoration under a high AOD scenario can explain most of the aerosol-associated changes in cloud fraction, cloud top pressure, and surface rainfall over this region.
Y. Tubul, I. Koren, and O. Altaratz
Earth Syst. Dynam., 6, 781–788, https://doi.org/10.5194/esd-6-781-2015, https://doi.org/10.5194/esd-6-781-2015, 2015
Y. Ben Ami, O. Altaratz, Y. Yair, and I. Koren
Nat. Hazards Earth Syst. Sci., 15, 2449–2459, https://doi.org/10.5194/nhess-15-2449-2015, https://doi.org/10.5194/nhess-15-2449-2015, 2015
S. Fuzzi, U. Baltensperger, K. Carslaw, S. Decesari, H. Denier van der Gon, M. C. Facchini, D. Fowler, I. Koren, B. Langford, U. Lohmann, E. Nemitz, S. Pandis, I. Riipinen, Y. Rudich, M. Schaap, J. G. Slowik, D. V. Spracklen, E. Vignati, M. Wild, M. Williams, and S. Gilardoni
Atmos. Chem. Phys., 15, 8217–8299, https://doi.org/10.5194/acp-15-8217-2015, https://doi.org/10.5194/acp-15-8217-2015, 2015
Short summary
Short summary
Particulate matter (PM) constitutes one of the most challenging problems both for air quality and climate change policies. This paper reviews the most recent scientific results on the issue and the policy needs that have driven much of the increase in monitoring and mechanistic research over the last 2 decades. The synthesis reveals many new processes and developments in the science underpinning climate-PM interactions and the effects of PM on human health and the environment.
G. Feingold, I. Koren, T. Yamaguchi, and J. Kazil
Atmos. Chem. Phys., 15, 7351–7367, https://doi.org/10.5194/acp-15-7351-2015, https://doi.org/10.5194/acp-15-7351-2015, 2015
Short summary
Short summary
Most research on the relationship between aerosol and closed/open cell transitions tends to focus on the closed to open transition. Here we address the two-way transition between closed and open cellular states using a cloud resolving model. We find inherent asymmetry in the transitions and explain the source of the asymmetry. Results are supported by a dynamical system analogue to the full system.
G. Dagan, I. Koren, and O. Altaratz
Atmos. Chem. Phys., 15, 2749–2760, https://doi.org/10.5194/acp-15-2749-2015, https://doi.org/10.5194/acp-15-2749-2015, 2015
E. Tas, A. Teller, O. Altaratz, D. Axisa, R. Bruintjes, Z. Levin, and I. Koren
Atmos. Chem. Phys., 15, 2009–2017, https://doi.org/10.5194/acp-15-2009-2015, https://doi.org/10.5194/acp-15-2009-2015, 2015
G. Snider, C. L. Weagle, R. V. Martin, A. van Donkelaar, K. Conrad, D. Cunningham, C. Gordon, M. Zwicker, C. Akoshile, P. Artaxo, N. X. Anh, J. Brook, J. Dong, R. M. Garland, R. Greenwald, D. Griffith, K. He, B. N. Holben, R. Kahn, I. Koren, N. Lagrosas, P. Lestari, Z. Ma, J. Vanderlei Martins, E. J. Quel, Y. Rudich, A. Salam, S. N. Tripathi, C. Yu, Q. Zhang, Y. Zhang, M. Brauer, A. Cohen, M. D. Gibson, and Y. Liu
Atmos. Meas. Tech., 8, 505–521, https://doi.org/10.5194/amt-8-505-2015, https://doi.org/10.5194/amt-8-505-2015, 2015
Short summary
Short summary
We have initiated a global network of ground-level monitoring stations to measure concentrations of fine aerosols in urban environments. Our findings include major ions species, total mass, and total scatter at three wavelengths. Results will be used to further evaluate and enhance satellite remote sensing estimates.
E. Hirsch, I. Koren, Z. Levin, O. Altaratz, and E. Agassi
Atmos. Chem. Phys., 14, 9001–9012, https://doi.org/10.5194/acp-14-9001-2014, https://doi.org/10.5194/acp-14-9001-2014, 2014
A. K. Mishra, K. Klingmueller, E. Fredj, J. Lelieveld, Y. Rudich, and I. Koren
Atmos. Chem. Phys., 14, 7213–7231, https://doi.org/10.5194/acp-14-7213-2014, https://doi.org/10.5194/acp-14-7213-2014, 2014
R. H. Heiblum, I. Koren, and G. Feingold
Atmos. Chem. Phys., 14, 6063–6074, https://doi.org/10.5194/acp-14-6063-2014, https://doi.org/10.5194/acp-14-6063-2014, 2014
G. Feingold and I. Koren
Nonlin. Processes Geophys., 20, 1011–1021, https://doi.org/10.5194/npg-20-1011-2013, https://doi.org/10.5194/npg-20-1011-2013, 2013
E. Hirsch, I. Koren, O. Altaratz, Z. Levin, and E. Agassi
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acpd-13-28729-2013, https://doi.org/10.5194/acpd-13-28729-2013, 2013
Revised manuscript not accepted
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
Extensive coverage of ultrathin tropical tropopause layer cirrus clouds revealed by balloon-borne lidar observations
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
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Thomas Lesigne, François Ravetta, Aurélien Podglajen, Vincent Mariage, and Jacques Pelon
Atmos. Chem. Phys., 24, 5935–5952, https://doi.org/10.5194/acp-24-5935-2024, https://doi.org/10.5194/acp-24-5935-2024, 2024
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Cited articles
Agee, E. M., Chen, T., and Dowell, K.: A review of mesoscale cellular convection, B. Am. Meteorol. Soc., 54, 1004–1012, 1973. a
Atkinson, B. W. and Wu Zhang, J.: Mesoscale shallow convection in the atmosphere, Rev. Geophys., 34, 403–431, https://doi.org/10.1029/96RG02623, 1996. a
Berg, L. K. and Kassianov, E. I.: Temporal Variability of Fair-Weather Cumulus Statistics at the ACRF SGP Site, J. Climate, 21, 3344–3358, https://doi.org/10.1175/2007JCLI2266.1, 2008. a
Berg, L. K., Kassianov, E. I., Long, C. N., and Mills Jr., D. L.: Surface summertime radiative forcing by shallow cumuli at the Atmospheric Radiation Measurement Southern Great Plains site, J. Geophys. Res.-Atmos., 116, D01202, https://doi.org/10.1029/2010JD014593, 2011. a
Bony, S.: Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models, Geophys. Res. Lett., 32, L20806, https://doi.org/10.1029/2005GL023851, 2005. a
Bony, S., Dufresne, J.-L., Le Treut, H., Morcrette, J.-J., and Senior, C.: On dynamic and thermodynamic components of cloud changes, Clim. Dynam., 22, 71–86, 2004. a
Boucher, O., Randall, D., Artaxo, P., Bretherton, C., Feingold, G.,
Forster, P., Kerminen, V.-M., Kondo, Y., Liao, H., Lohmann,
U., Rasch, P., Satheesh, S. K., Sherwood, S., Stevens, B., and
Zhang, X. Y.: Clouds and aerosols, in: Climate Change 2013:
The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Stocker, T. F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S. K., Doschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P. M.: Cambridge University Press, United Kingdom and New York USA, 571–657, https://doi.org/10.1017/CBO9781107415324.016, 2013. a
Chekroun, M. and Kondrashov, D.: Data-adaptive harmonic spectra and multilayer Stuart-Landau models, Chaos, 27, 093110, https://doi.org/10.1063/1.4989400, 2017. a
Chekroun, M. D., Kondrashov, D., and Ghil, M.: Predicting stochastic systems by noise sampling, and application to the El Niño-Southern Oscillation, P. Natl. Acad. Sci. USA, 108, 11766–11771, https://doi.org/10.1073/pnas.1015753108, 2011. a, b
Chen, C., Cane, M. A., Henderson, N., Lee, D. E., Chapman, D., Kondrashov, D., and Chekroun, M.: Diversity, Nonlinearity, Seasonality, and Memory Effect in ENSO Simulation and Prediction Using Empirical Model Reduction, J. Climate, 29, 1809–1830, 2016. a
Cheng, X., Nitsche, G., and Wallace, J. M.: Robustness of low-frequency circulation patterns derived from EOF and rotated EOF analyses, J. Climate, 8, 1709–1713, 1995. a
Dagan, G., Koren, I., Kostinski, A., and Altaratz, O.: Organization and oscillations in simulated shallow convective clouds, J. Adv. Model. Earth Sy., 10, 2287–2299, 2018. a
DelSole, T. and Tippett, M. K.: Average predictability time. Part I: theory, J. Atmos. Sci., 66, 1172–1187, 2009. a
Fukuoka, A.: The central meteorological observatory, a study on 10-day forecast (a synthetic report), Geophysical Magazine, 22, 177–208, 1951. a
GOES-R Algorithm Working Group and GOES-R Program Office: NOAA GOES-R Series Advanced Baseline Imager (ABI) Level 2 Cloud Top Phase (ACTP), CONUS subset, NOAA National Centers for Environmental Information [data set], https://doi.org/10.7289/V5NP22QW, 2018a. a, b
GOES-R Algorithm Working Group and GOES-R Series Program Office: NOAA GOES-R Series Advanced Baseline Imager (ABI) Level 2 Cloud Top Height (ACHA), CONUS subset, NOAA National Centers for Environmental Information [data set], https://doi.org/10.7289/V5HX19ZQ, 2018.
GOES-R Calibration Working Group and GOES-R Series Program: NOAA GOES-R Series Advanced Baseline Imager (ABI) Level 1b Radiances, CONUS subset, NOAA National Centers for Environmental Information [data set], https://doi.org/10.7289/V5BV7DSR, 2017. a
Greene, C. A., Thirumalai, K., Kearney, K. A., Delgado, J. M., Schwanghart, W., Wolfenbarger, N. S., Thyng, K. M., Gwyther, D. E., Gardner, A. S., and Blankenship, D. D.: The climate data toolbox for MATLAB, Geochem. Geophy. Geosy., 20, 3774–3781, https://doi.org/10.1029/2019GC008392, 2019. a
Groth, A. and Ghil, M.: Multivariate singular spectrum analysis and the road to phase synchronization, Phys. Rev. E, 84, 036206, https://doi.org/10.1103/PhysRevE.84.036206, 2011. a
Hannachi, A., Jolliffe, I., Stephenson, D., and Trendafilov, N.: In search of simple structures in climate: simplifying EOFs, Int. J. Climatol., 26, 7–28, 2006. a
Hauf, T. and Clark, T. L.: Three-dimensional numerical experiments on convectively forced internal gravity waves, Q. J. Roy. Meteor. Soc., 115, 309–333, 1989. a
Heiblum, R. H., Koren, I., and Feingold, G.: On the link between Amazonian forest properties and shallow cumulus cloud fields, Atmos. Chem. Phys., 14, 6063–6074, https://doi.org/10.5194/acp-14-6063-2014, 2014. a
Heus, T. and Seifert, A.: Automated tracking of shallow cumulus clouds in large domain, long duration large eddy simulations, Geosci. Model Dev., 6, 1261–1273, https://doi.org/10.5194/gmd-6-1261-2013, 2013. a
Hinkelman, L. and Evans, K.: Anisotropy in Broken Cloud Fields Over Oklahoma
from Landsat Data, Fourteenth ARM Science Team Meeting Proceedings,
Albuquerque, New Mexico, 22–26 March 2004. a
Horel, J. D.: A rotated principal component analysis of the interannual variability of the Northern Hemisphere 500 mb height field, Mon. Weather Rev., 109, 2080–2092, 1981. a
Jaeckisch, H.: Synoptic conditions of wave formation above convective streets, OSTIV Publications, Braunschweig, Germany, 12, 1972. a
Jakub, F. and Mayer, B.: The role of 1-D and 3-D radiative heating in the organization of shallow cumulus convection and the formation of cloud streets, Atmos. Chem. Phys., 17, 13317–13327, https://doi.org/10.5194/acp-17-13317-2017, 2017. a
Jolliffe, I.: Principal Component Analysis, 2nd Edn., Springer, New York, 2002. a
Kawamura, R.: A rotated EOF analysis of global sea surface temperature variability with interannual and interdecadal scales, J. Phys. Oceanogr., 24, 707–715, 1994. a
Klitch, M. A., Weaver, J. F., Kelly, F. P., and Vonder Haar, T. H.: Convective cloud climatologies constructed from satellite imagery, Mon. Weather Rev., 113, 326–337, 1985. a
Kondrashov, D., Chekroun, M., and Berloff, P.: Multiscale Stuart-Landau emulators: Application to wind-driven ocean gyres, Fluids, 3, 21, https://doi.org/10.3390/fluids3010021, 2018a. a
Kondrashov, D., Chekroun, M. D., Yuan, X., and Ghil, M.: Data-adaptive harmonic decomposition and stochastic modeling of Arctic sea ice, in: Advances in Nonlinear Geosciences, edited by: A. Tsonis, Springer, Cham, Switzerland, 179–205, 2018b. a
Koren, I.: Data from: Deciphering Organization of GOES–16 Green Cumulus, through the EOF lens, The Weizmann Institute of Science [data set], https://doi.org/10.34933/wis.000007, 2020. a
Lane, T. P.: Convectively generated gravity waves, in: Encyclopedia of Atmospheric Sciences, 2nd Edn., Elsevier, Amsterdam, Netherland, 171–179, 2015. a
Lane, T. P. and Reeder, M. J.: Convectively generated gravity waves and their effect on the cloud environment, J. Atmos. Sci., 58, 2427–2440, 2001. a
Lorenz, E. N.: Empirical orthogonal functions and statistical weather
prediction, Scientific Report no. 1, Statistical Forecasting Project, Massachusetts Institute of Technology, Department of Meteorology Cambridge,
1956. a
Melfi, S. and Palm, S. P.: Estimating the orientation and spacing of midlatitude linear convective boundary layer features: Cloud streets, J. Atmos. Sci., 69, 352–364, 2012. a
Messié, M. and Chavez, F.: Global modes of sea surface temperature variability in relation to regional climate indices, J. Climate, 24, 4314–4331, 2011. a
Mestas-Nuñez, A. M. and Enfield, D. B.: Rotated global modes of non-ENSO sea surface temperature variability, J. Climate, 12, 2734–2746, 1999. a
Monahan, A. H., Fyfe, J. C., Ambaum, M. H., Stephenson, D. B., and North, G. R.: Empirical orthogonal functions: The medium is the message, J. Climate, 22, 6501–6514, 2009. a
Müller, D., Etling, D., Kottmeier, C., and Roth, R.: On the occurrence of cloud streets over northern Germany, Q. J. Roy. Meteor. Soc., 111, 761–772, 1985. a
Nair, U., Weger, R., Kuo, K., and Welch, R.: Clustering, randomness, and regularity in cloud fields: 5. The nature of regular cumulus cloud fields, J. Geophys. Res.-Atmos., 103, 11363–11380, 1998. a
Nappo, C. J.: An Introduction to Atmospheric Gravity Waves, Academic press, Cambridge, Massachusetts, USA, 2013. a
NASA JPL: NASA Shuttle Radar Topography Mission Global 1 arc second, SRTMGL1 v003, NASA EOSDIS Land Processes DAAC [data set], https://doi.org/10.5067/MEaSUREs/SRTM/SRTMGL1.003, 2013. a
Norris, J. R.: Low cloud type over the ocean from surface observations. Part II: Geographical and seasonal variations, J. Climate, 11, 383–403, 1998. a
Nuijens, L. and Siebesma, A. P.: Boundary layer clouds and convection over subtropical oceans in our current and in a warmer climate, Current Climate Change Reports, 5, 80–94, 2019. a
Penland, C. and Magorian, T.: Prediction of Niño 3 sea surface temperatures using linear inverse modeling, J. Climate, 6, 1067–1076, 1993. a
Penland, C. and Sardeshmukh, P. D.: The optimal growth of tropical sea surface temperature anomalies, J. Climate, 8, 1999–2024, 1995. a
Rabin, R. M. and Martin, D. W.: Satellite observations of shallow cumulus coverage over the central United States: An exploration of land use impact on cloud cover, J. Geophys. Res.-Atmos., 101, 7149–7155, 1996. a
Ray, D. K., Nair, U. S., Welch, R. M., Han, Q., Zeng, J., Su, W., Kikuchi, T., and Lyons, T. J.: Effects of land use in Southwest Australia: 1. Observations of cumulus cloudiness and energy fluxes, J. Geophys. Res.-Atmos., 108, 4414, https://doi.org/10.1029/2002JD002654, 2003. a
Richman, M. B.: Obliquely rotated principal components: An improved meteorological map typing technique?, J. Appl. Meteorol., 20, 1145–1159, 1981. a
Richman, M. B.: Rotation of principal components, J. Climatol., 6, 293–335, 1986. a
Roundy, P. E. and Schreck III, C. J.: A combined wave-number–frequency and time-extended EOF approach for tracking the progress of modes of large-scale organized tropical convection, Q. J. Roy. Meteor. Soc., 135, 161–173, 2009. a
Schmit, T., Gunshor, M., Fu, G., Rink, T., Bah, K., and Wolf, W.: GOES-R Advanced Baseline Imager (ABI) Algorithm Theoretical Basis Document for: Cloud and Moisture Imagery Product (CMIP), University of Wisconsin–Madison, Madison, Wisconsin, USA, 2010. a
Seifert, A. and Heus, T.: Large-eddy simulation of organized precipitating trade wind cumulus clouds, Atmos. Chem. Phys., 13, 5631–5645, https://doi.org/10.5194/acp-13-5631-2013, 2013. a, b
Simpson, J.: Cumulus clouds: Early aircraft observations and entrainment hypotheses, in: Mesoscale Meteorology – Theories, Observations and Models, Springer, Berlin/Heidelberg, Germany, 355–373, 1983. a
Stevens, B., Bony, S., Brogniez, H., Hentgen, L., Hohenegger, C., Kiemle, C., L'Ecuyer, T., Naumann, A., Schulz, H., Siebesma, P., Vial, J., Winker, D., and Zuidema, P.: Sugar, gravel, fish and
flowers: Mesoscale cloud patterns in the trade winds, Q. J. Roy. Meteor. Soc., 146,
1–12, 2019. a
Stull, R. B.: Internal gravity waves generated by penetrative convection, J. Atmos. Sci., 33, 1279–1286, 1976. a
Thompson, D. W. and Wallace, J. M.: The Arctic Oscillation signature in the wintertime geopotential height and temperature fields, Geophys. Res. Lett., 25, 1297–1300, 1998. a
Tobin, I., Bony, S., and Roca, R.: Observational evidence for relationships between the degree of aggregation of deep convection, water vapor, surface fluxes, and radiation, J. Climate, 25, 6885–6904, 2012. a
Tsuda, T.: Characteristics of atmospheric gravity waves observed using the MU (Middle and Upper atmosphere) radar and GPS (Global Positioning System) radio occultation, P. Jpn. Acad. B-Phys., 90, 12–27, 2014. a
Turner, D. D., Vogelmann, A. M., Austin, R. T., Barnard, J. C., Cady-Pereira, K., Chiu, J. C., Clough, S. A., Flynn, C., Khaiyer, M. M., Liljegren, J., Johnson, K., Lin, B., Long, C., Marshak, A., Matrosov, S. Y., McFarlane, S. A., Miller, M., Min, Q., Minimis, P., O'Hirok, W., Wang, Z., and Wiscombe, W.: Thin liquid water clouds: their importance and our challenge, B. Am. Meteorol. Soc., 88, 177–190, https://doi.org/10.1175/BAMS-88-2-177, 2007. a
Vial, J., Bony, S., Stevens, B., and Vogel, R.: Mechanisms and model diversity of trade-wind shallow cumulus cloud feedbacks: a review, in: Shallow Clouds, Water Vapor, Circulation, and Climate Sensitivity, Springer, NYC, NY, USA, 159–181, 2017. a
Weare, B. C. and Nasstrom, J. S.: Examples of extended empirical orthogonal function analyses, Mon. Weather Rev., 110, 481–485, 1982. a
Webb, M. J., Senior, C., Sexton, D., Ingram, W., Williams, K., Ringer, M., McAvaney, B., Colman, R., Soden, B. J., Gudgel, R., Knutson, T., Emori, S., Ogura, T., Tsushima, Y., Andronova, N., Li, B., Musat, I., Bony, S., and Taylor, K. E.: On the contribution of local feedback mechanisms to the range of climate sensitivity in two GCM ensembles, Clim. Dynam., 27, 17–38, 2006. a
Weckwerth, T. M., Wilson, J. W., Wakimoto, R. M., and Crook, N. A.: Horizontal convective rolls: Determining the environmental conditions supporting their existence and characteristics, Mon. Weather Rev., 125, 505–526, 1997. a
Wing, A. A. and Emanuel, K. A.: Physical mechanisms controlling self-aggregation of convection in idealized numerical modeling simulations, J. Adv. Model. Earth Sy., 6, 59–74, 2014. a
Xue, H., Feingold, G., and Stevens, B.: Aerosol effects on clouds, precipitation, and the organization of shallow cumulus convection, J. Atmos. Sci., 65, 392–406, 2008. a
Zelinka, M. D., Myers, T. A., McCoy, D. T., Po-Chedley, S., Caldwell, P. M., Ceppi, P., Klein, S. A., and Taylor, K. E.: Causes of higher climate sensitivity in CMIP6 models, Geophys. Res. Lett., 47, e2019GL085782, https://doi.org/10.1029/2019GL085782, 2020. a
Zhang, Y. and Klein, S. A.: Factors Controlling the Vertical Extent of Fair-Weather Shallow Cumulus Clouds over Land: Investigation of Diurnal-Cycle Observations Collected at the ARM Southern Great Plains Site, J. Atmos. Sci., 70, 1297–1315, https://doi.org/10.1175/JAS-D-12-0131.1, 2013. a, b
Zhu, P.: Large eddy simulations of continental shallow cumulus convection, J. Geophys. Res., 108, 4453, https://doi.org/10.1029/2002JD003119, 2003. a
Zhu, P. and Albrecht, B.: A theoretical and observational analysis on the formation of fair-weather cumuli, J. Atmos. Sci., 59, 1983–2005, 2002. a
Zhu, T., Lee, J., Weger, R., and Welch, R.: Clustering, randomness, and regularity in cloud fields: 2. Cumulus cloud fields, J. Geophys. Res.-Atmos., 97, 20537–20558, 1992. a
Short summary
A part of continental shallow convective cumulus (Cu) was shown to share properties such as organization and formation over vegetated areas, thus named green Cu. Mechanisms behind the formed patterns are not understood. We use different metrics and an empirical orthogonal function (EOF) to decompose the dataset and quantify organization factors (cloud streets and gravity waves). We show that clouds form a highly organized grid structure over hundreds of kilometers at the field lifetime.
A part of continental shallow convective cumulus (Cu) was shown to share properties such as...
Altmetrics
Final-revised paper
Preprint