Articles | Volume 19, issue 7
Atmos. Chem. Phys., 19, 4383–4392, 2019
https://doi.org/10.5194/acp-19-4383-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue: New observations and related modelling studies of the aerosol–cloud–climate...
Atmos. Chem. Phys., 19, 4383–4392, 2019
https://doi.org/10.5194/acp-19-4383-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article 04 Apr 2019
Research article | 04 Apr 2019
Spatiotemporal dynamics of fog and low clouds in the Namib unveiled with ground- and space-based observations
Hendrik Andersen et al.
Related authors
Babak Jahani, Hendrik Andersen, Josep Calbó, Josep-Abel González, and Jan Cermak
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-421, https://doi.org/10.5194/acp-2021-421, 2021
Preprint under review for ACP
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The change in the state of sky from cloudy to cloudless (or vice versa) comprises an additional phase called “transition zone” with characteristics laying between those of aerosols and clouds. This study presents an approach for quantification of cloud-aerosol transition zone broadband longwave radiative effects at the top of the atmosphere during daytime over the ocean, based on satellite observations and radiative transfer simulations.
Roland Stirnberg, Jan Cermak, Simone Kotthaus, Martial Haeffelin, Hendrik Andersen, Julia Fuchs, Miae Kim, Jean-Eudes Petit, and Olivier Favez
Atmos. Chem. Phys., 21, 3919–3948, https://doi.org/10.5194/acp-21-3919-2021, https://doi.org/10.5194/acp-21-3919-2021, 2021
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Air pollution endangers human health and poses a problem particularly in densely populated areas. Here, an explainable machine learning approach is used to analyse periods of high particle concentrations for a suburban site southwest of Paris to better understand its atmospheric drivers. Air pollution is particularly excaberated by low temperatures and low mixed layer heights, but processes vary substantially between and within seasons.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Peter Knippertz, Marco Gaetani, Julian Quinting, Sebastian Sippel, and Roland Vogt
Atmos. Chem. Phys., 20, 3415–3438, https://doi.org/10.5194/acp-20-3415-2020, https://doi.org/10.5194/acp-20-3415-2020, 2020
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Fog and low clouds (FLCs) are an essential but poorly understood element of Namib regional climate. Here, a satellite-based data set of FLCs in central Namib, reanalysis data, and back trajectories are used to systematically analyze conditions when FLCs occur. Synoptic-scale mechanisms are identified that influence the formation of FLCs and the onshore advection of marine boundary-layer air masses. The findings lead to a new conceptual model of mechanisms that drive FLC variability in the Namib.
Karmen Babić, Bianca Adler, Norbert Kalthoff, Hendrik Andersen, Cheikh Dione, Fabienne Lohou, Marie Lothon, and Xabier Pedruzo-Bagazgoitia
Atmos. Chem. Phys., 19, 1281–1299, https://doi.org/10.5194/acp-19-1281-2019, https://doi.org/10.5194/acp-19-1281-2019, 2019
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The first detailed observational analysis of the complete diurnal cycle of low-level clouds (LLC) and associated atmospheric processes over southern West Africa is performed using the data gathered within the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud-Interactions in West Africa) ground-based campaign. We find cooling related to the horizontal advection, which occurs in connection with the inflow of cool maritime air mass and a prominent low-level jet, to have the dominant role in LLC formation.
Bianca Adler, Karmen Babić, Norbert Kalthoff, Fabienne Lohou, Marie Lothon, Cheikh Dione, Xabier Pedruzo-Bagazgoitia, and Hendrik Andersen
Atmos. Chem. Phys., 19, 663–681, https://doi.org/10.5194/acp-19-663-2019, https://doi.org/10.5194/acp-19-663-2019, 2019
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This study deals with nocturnal stratiform low-level clouds that frequently form in the atmospheric boundary layer over southern West Africa. We use observational data from 11 nights to characterize the clouds and intranight variability of boundary layer conditions as well as to assess the physical processes relevant for cloud formation. We find that cooling is crucial to reach saturation and a large part of the cooling is related to horizontal advection of cool air from the Gulf of Guinea.
Julia Fuchs, Jan Cermak, and Hendrik Andersen
Atmos. Chem. Phys., 18, 16537–16552, https://doi.org/10.5194/acp-18-16537-2018, https://doi.org/10.5194/acp-18-16537-2018, 2018
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This study separates the influence of aerosol on cloud properties in the southeast Atlantic region from meteorological conditions in the biomass-burning season. Machine learning is used to link 8-day-averaged satellite and reanalysis data sets. Distinct regimes of aerosol–cloud interactions are identified in the subregions of the southeast Atlantic based on the obtained sensitivities.
Hendrik Andersen and Jan Cermak
Atmos. Meas. Tech., 11, 5461–5470, https://doi.org/10.5194/amt-11-5461-2018, https://doi.org/10.5194/amt-11-5461-2018, 2018
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Fog and low clouds (FLCs) are a valuable source of water for many ecosystems in the Namib. This study presents the first fully diurnal satellite detection of FLCs, revealing the spatial and temporal patterns in the Namib. A validation is conducted against station measurements in the central Namib and shows a high overall accuracy. The average timing and persistence of FLCs seem to depend on the distance to the coast, suggesting that the region is dominated by advection-driven FLCs.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Reto Knutti, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 9535–9546, https://doi.org/10.5194/acp-17-9535-2017, https://doi.org/10.5194/acp-17-9535-2017, 2017
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Aerosol-cloud interactions continue to contribute large uncertainties to our climate system understanding. In this study, we use near-global satellite and reanalysis data sets to predict marine liquid-water clouds by means of artificial neural networks. We show that on the system scale, lower-tropospheric stability and boundary layer height are the main determinants of liquid-water clouds. Aerosols show the expected impact on clouds but are less relevant than some meteorological factors.
Babak Jahani, Hendrik Andersen, Josep Calbó, Josep-Abel González, and Jan Cermak
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-421, https://doi.org/10.5194/acp-2021-421, 2021
Preprint under review for ACP
Short summary
Short summary
The change in the state of sky from cloudy to cloudless (or vice versa) comprises an additional phase called “transition zone” with characteristics laying between those of aerosols and clouds. This study presents an approach for quantification of cloud-aerosol transition zone broadband longwave radiative effects at the top of the atmosphere during daytime over the ocean, based on satellite observations and radiative transfer simulations.
Roland Stirnberg, Jan Cermak, Simone Kotthaus, Martial Haeffelin, Hendrik Andersen, Julia Fuchs, Miae Kim, Jean-Eudes Petit, and Olivier Favez
Atmos. Chem. Phys., 21, 3919–3948, https://doi.org/10.5194/acp-21-3919-2021, https://doi.org/10.5194/acp-21-3919-2021, 2021
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Air pollution endangers human health and poses a problem particularly in densely populated areas. Here, an explainable machine learning approach is used to analyse periods of high particle concentrations for a suburban site southwest of Paris to better understand its atmospheric drivers. Air pollution is particularly excaberated by low temperatures and low mixed layer heights, but processes vary substantially between and within seasons.
Gianluca Mussetti, Dominik Brunner, Stephan Henne, Jonas Allegrini, E. Scott Krayenhoff, Sebastian Schubert, Christian Feigenwinter, Roland Vogt, Andreas Wicki, and Jan Carmeliet
Geosci. Model Dev., 13, 1685–1710, https://doi.org/10.5194/gmd-13-1685-2020, https://doi.org/10.5194/gmd-13-1685-2020, 2020
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Street trees are regarded as a powerful measure to reduce excessive heat in cities. To enable city-wide studies of the cooling effect of street trees, we developed a coupled urban climate model with explicit representation of street trees (COSMO-BEP-Tree). The model compares well with surface, flux and satellite observations and responds realistically to changes in tree characteristics. Street trees largely impact energy fluxes and wind speed, while air temperatures are only slightly reduced.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Peter Knippertz, Marco Gaetani, Julian Quinting, Sebastian Sippel, and Roland Vogt
Atmos. Chem. Phys., 20, 3415–3438, https://doi.org/10.5194/acp-20-3415-2020, https://doi.org/10.5194/acp-20-3415-2020, 2020
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Fog and low clouds (FLCs) are an essential but poorly understood element of Namib regional climate. Here, a satellite-based data set of FLCs in central Namib, reanalysis data, and back trajectories are used to systematically analyze conditions when FLCs occur. Synoptic-scale mechanisms are identified that influence the formation of FLCs and the onshore advection of marine boundary-layer air masses. The findings lead to a new conceptual model of mechanisms that drive FLC variability in the Namib.
Karmen Babić, Bianca Adler, Norbert Kalthoff, Hendrik Andersen, Cheikh Dione, Fabienne Lohou, Marie Lothon, and Xabier Pedruzo-Bagazgoitia
Atmos. Chem. Phys., 19, 1281–1299, https://doi.org/10.5194/acp-19-1281-2019, https://doi.org/10.5194/acp-19-1281-2019, 2019
Short summary
Short summary
The first detailed observational analysis of the complete diurnal cycle of low-level clouds (LLC) and associated atmospheric processes over southern West Africa is performed using the data gathered within the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud-Interactions in West Africa) ground-based campaign. We find cooling related to the horizontal advection, which occurs in connection with the inflow of cool maritime air mass and a prominent low-level jet, to have the dominant role in LLC formation.
Matthias Wiegner, Ina Mattis, Margit Pattantyús-Ábrahám, Juan Antonio Bravo-Aranda, Yann Poltera, Alexander Haefele, Maxime Hervo, Ulrich Görsdorf, Ronny Leinweber, Josef Gasteiger, Martial Haeffelin, Frank Wagner, Jan Cermak, Katerina Komínková, Mike Brettle, Christoph Münkel, and Kornelia Pönitz
Atmos. Meas. Tech., 12, 471–490, https://doi.org/10.5194/amt-12-471-2019, https://doi.org/10.5194/amt-12-471-2019, 2019
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Many ceilometers are influenced by water vapor absorption in the spectral range around 910 nm. Thus, a correction is required to retrieve aerosol optical properties. Validation of this correction scheme was performed in the framework of CeiLinEx2015 for several ceilometers with good agreement for Vaisala's CL51 ceilometer. For future applications we recommend monitoring the emitted wavelength and providing
darkmeasurements on a regular basis to be able to correct for signal artifacts.
Bianca Adler, Karmen Babić, Norbert Kalthoff, Fabienne Lohou, Marie Lothon, Cheikh Dione, Xabier Pedruzo-Bagazgoitia, and Hendrik Andersen
Atmos. Chem. Phys., 19, 663–681, https://doi.org/10.5194/acp-19-663-2019, https://doi.org/10.5194/acp-19-663-2019, 2019
Short summary
Short summary
This study deals with nocturnal stratiform low-level clouds that frequently form in the atmospheric boundary layer over southern West Africa. We use observational data from 11 nights to characterize the clouds and intranight variability of boundary layer conditions as well as to assess the physical processes relevant for cloud formation. We find that cooling is crucial to reach saturation and a large part of the cooling is related to horizontal advection of cool air from the Gulf of Guinea.
Julia Fuchs, Jan Cermak, and Hendrik Andersen
Atmos. Chem. Phys., 18, 16537–16552, https://doi.org/10.5194/acp-18-16537-2018, https://doi.org/10.5194/acp-18-16537-2018, 2018
Short summary
Short summary
This study separates the influence of aerosol on cloud properties in the southeast Atlantic region from meteorological conditions in the biomass-burning season. Machine learning is used to link 8-day-averaged satellite and reanalysis data sets. Distinct regimes of aerosol–cloud interactions are identified in the subregions of the southeast Atlantic based on the obtained sensitivities.
Hendrik Andersen and Jan Cermak
Atmos. Meas. Tech., 11, 5461–5470, https://doi.org/10.5194/amt-11-5461-2018, https://doi.org/10.5194/amt-11-5461-2018, 2018
Short summary
Short summary
Fog and low clouds (FLCs) are a valuable source of water for many ecosystems in the Namib. This study presents the first fully diurnal satellite detection of FLCs, revealing the spatial and temporal patterns in the Namib. A validation is conducted against station measurements in the central Namib and shows a high overall accuracy. The average timing and persistence of FLCs seem to depend on the distance to the coast, suggesting that the region is dominated by advection-driven FLCs.
Amelie Driemel, John Augustine, Klaus Behrens, Sergio Colle, Christopher Cox, Emilio Cuevas-Agulló, Fred M. Denn, Thierry Duprat, Masato Fukuda, Hannes Grobe, Martial Haeffelin, Gary Hodges, Nicole Hyett, Osamu Ijima, Ain Kallis, Wouter Knap, Vasilii Kustov, Charles N. Long, David Longenecker, Angelo Lupi, Marion Maturilli, Mohamed Mimouni, Lucky Ntsangwane, Hiroyuki Ogihara, Xabier Olano, Marc Olefs, Masao Omori, Lance Passamani, Enio Bueno Pereira, Holger Schmithüsen, Stefanie Schumacher, Rainer Sieger, Jonathan Tamlyn, Roland Vogt, Laurent Vuilleumier, Xiangao Xia, Atsumu Ohmura, and Gert König-Langlo
Earth Syst. Sci. Data, 10, 1491–1501, https://doi.org/10.5194/essd-10-1491-2018, https://doi.org/10.5194/essd-10-1491-2018, 2018
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The Baseline Surface Radiation Network (BSRN) collects and centrally archives high-quality ground-based radiation measurements in 1 min resolution. More than 10 300 months, i.e., > 850 years, of high-radiation data in 1 min resolution from the years 1992 to 2017 are available. The network currently comprises 59 stations collectively representing all seven continents as well as island-based stations in the Pacific, Atlantic, Indian and Arctic oceans.
Arve Kylling, Sophie Vandenbussche, Virginie Capelle, Juan Cuesta, Lars Klüser, Luca Lelli, Thomas Popp, Kerstin Stebel, and Pepijn Veefkind
Atmos. Meas. Tech., 11, 2911–2936, https://doi.org/10.5194/amt-11-2911-2018, https://doi.org/10.5194/amt-11-2911-2018, 2018
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The aerosol layer height is one of four aerosol parameters which is needed to enhance our understanding of aerosols' role in the climate system. Both active and passive measurement methods may be used to estimate the aerosol layer height. Aerosol height estimates made from passive infrared and solar satellite sensors measurements are compared with satellite-borne lidar estimates. There is considerable variation between the retrieved dust heights and how they compare with the lidar.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Reto Knutti, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 9535–9546, https://doi.org/10.5194/acp-17-9535-2017, https://doi.org/10.5194/acp-17-9535-2017, 2017
Short summary
Short summary
Aerosol-cloud interactions continue to contribute large uncertainties to our climate system understanding. In this study, we use near-global satellite and reanalysis data sets to predict marine liquid-water clouds by means of artificial neural networks. We show that on the system scale, lower-tropospheric stability and boundary layer height are the main determinants of liquid-water clouds. Aerosols show the expected impact on clouds but are less relevant than some meteorological factors.
Kai-Uwe Eichmann, Luca Lelli, Christian von Savigny, Harjinder Sembhi, and John P. Burrows
Atmos. Meas. Tech., 9, 793–815, https://doi.org/10.5194/amt-9-793-2016, https://doi.org/10.5194/amt-9-793-2016, 2016
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Height-resolved limb radiance spectra of the satellite instrument SCIAMACHY are used to retrieve cloud top heights with a colour index method. Clouds are detectable from the lower to the uppermost troposphere. These cloud heights help to improve the trace gas retrieval for the upper troposphere and lower stratosphere. Comparisons with other data sets have shown good agreement. As clouds and aerosols are not distinguishable, lower stratospheric volcanic aerosol clouds are detected in some years.
F. Kaspar, J. Helmschrot, A. Mhanda, M. Butale, W. de Clercq, J. K. Kanyanga, F. O. S. Neto, S. Kruger, M. Castro Matsheka, G. Muche, T. Hillmann, K. Josenhans, R. Posada, J. Riede, M. Seely, C. Ribeiro, P. Kenabatho, R. Vogt, and N. Jürgens
Adv. Sci. Res., 12, 171–177, https://doi.org/10.5194/asr-12-171-2015, https://doi.org/10.5194/asr-12-171-2015, 2015
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One task of the “Southern African Science Service Centre for Climate Change and Adaptive Land Management” (www.sasscal.org) is the provision of climate data for Southern Africa. Extension and improvements of observational networks in Angola, Botswana, Namibia, Zambia and South Africa are supported. This effort is complemented by an improvement of climate data management at national weather authorities, capacity building activities and an extension of the data bases with historical climate data.
L. Lelli, A. A. Kokhanovsky, V. V. Rozanov, M. Vountas, and J. P. Burrows
Atmos. Chem. Phys., 14, 5679–5692, https://doi.org/10.5194/acp-14-5679-2014, https://doi.org/10.5194/acp-14-5679-2014, 2014
E. Hammer, N. Bukowiecki, M. Gysel, Z. Jurányi, C. R. Hoyle, R. Vogt, U. Baltensperger, and E. Weingartner
Atmos. Chem. Phys., 14, 1123–1139, https://doi.org/10.5194/acp-14-1123-2014, https://doi.org/10.5194/acp-14-1123-2014, 2014
N. Schaller, J. Cermak, M. Wild, and R. Knutti
Earth Syst. Dynam., 4, 253–266, https://doi.org/10.5194/esd-4-253-2013, https://doi.org/10.5194/esd-4-253-2013, 2013
Related subject area
Subject: Clouds and Precipitation | Research Activity: Remote Sensing | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Lidar observations of cirrus clouds in Palau (7°33′ N, 134°48′ E)
Observing the timescales of aerosol–cloud interactions in snapshot satellite images
Potential impact of aerosols on convective clouds revealed by Himawari-8 observations over different terrain types in eastern China
How frequent is natural cloud seeding from ice cloud layers ( < −35 °C) over Switzerland?
Processes contributing to cloud dissipation and formation events on the North Slope of Alaska
Characterisation and surface radiative impact of Arctic low clouds from the IAOOS field experiment
A-Train estimates of the sensitivity of the cloud-to-rainwater ratio to cloud size, relative humidity, and aerosols
Ice injected into the tropopause by deep convection – Part 2: Over the Maritime Continent
3D radiative heating of tropical upper tropospheric cloud systems derived from synergistic A-Train observations and machine learning
Evaluation of the CMIP6 marine subtropical stratocumulus cloud albedo and its controlling factors
The potential of increasing man-made air pollution to reduce rainfall over southern West Africa
The dual-field-of-view polarization lidar technique: a new concept in monitoring aerosol effects in liquid-water clouds – theoretical framework
The dual-field-of-view polarization lidar technique: a new concept in monitoring aerosol effects in liquid-water clouds – case studies
Constraining the Twomey effect from satellite observations: issues and perspectives
Microphysical properties of three types of snow clouds: implication for satellite snowfall retrievals
Properties of ice cloud over Beijing from surface Ka-band radar observations during 2014–2017
Linkage among ice crystal microphysics, mesoscale dynamics, and cloud and precipitation structures revealed by collocated microwave radiometer and multifrequency radar observations
Identifying meteorological influences on marine low cloud mesoscale morphology using deep learning classifications
Possible mechanisms of summer cirrus clouds over the Tibetan Plateau
Mid-level clouds are frequent above the southeast Atlantic stratocumulus clouds
Towards the connection between snow microphysics and melting layer: insights from multifrequency and dual-polarization radar observations during BAECC
Cloud phase characteristics over Southeast Asia from A-Train satellite observations
Cloud regimes over the Amazon Basin: perspectives from the GoAmazon2014/5 campaign
Microphysics and dynamics of snowfall associated with a warm conveyor belt over Korea
Linking large-scale circulation patterns to low-cloud properties
Quantifying cloud adjustments and the radiative forcing due to aerosol–cloud interactions in satellite observations of warm marine clouds
Small-scale structure of thermodynamic phase in Arctic mixed-phase clouds observed by airborne remote sensing during a cold air outbreak and a warm air advection event
The influence of water vapor anomalies on clouds and their radiative effect at Ny-Ålesund
Variability in cirrus cloud properties using a PollyXT Raman lidar over high and tropical latitudes
Deconvolution of boundary layer depth and aerosol constraints on cloud water path in subtropical stratocumulus decks
Investigation of aerosol–cloud interactions under different absorptive aerosol regimes using Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) ground-based measurements
Low-level mixed-phase clouds in a complex Arctic environment
Synoptic-scale controls of fog and low-cloud variability in the Namib Desert
A new classification of satellite-derived liquid water cloud regimes at cloud scale
The day-to-day co-variability between mineral dust and cloud glaciation: a proxy for heterogeneous freezing
Retrieval of the vertical evolution of the cloud effective radius from the Chinese FY-4 (Feng Yun 4) next-generation geostationary satellites
The role of spring dry zonal advection in summer drought onset over the US Great Plains
Diurnal variation of high-level clouds from the synergy of AIRS and IASI space-borne infrared sounders
Analysis and quantification of ENSO-linked changes in the tropical Atlantic cloud vertical distribution using 14 years of MODIS observations
Variability in vertical structure of precipitation with sea surface temperature over the Arabian Sea and the Bay of Bengal as inferred by Tropical Rainfall Measuring Mission precipitation radar measurements
Spatial and temporal variability of snowfall over Greenland from CloudSat observations
Cloud responses to climate variability over the extratropical oceans as observed by MISR and MODIS
Antarctic clouds, supercooled liquid water and mixed phase, investigated with DARDAR: geographical and seasonal variations
Ice injected into the tropopause by deep convection – Part 1: In the austral convective tropics
Quantifying variations in shortwave aerosol–cloud–radiation interactions using local meteorology and cloud state constraints
Rapid ice aggregation process revealed through triple-wavelength Doppler spectrum radar analysis
Constraining the aerosol influence on cloud liquid water path
Northern Hemisphere contrail properties derived from Terra and Aqua MODIS data for 2006 and 2012
Lidar measurements of thin laminations within Arctic clouds
Statistics on clouds and their relation to thermodynamic conditions at Ny-Ålesund using ground-based sensor synergy
Francesco Cairo, Mauro De Muro, Marcel Snels, Luca Di Liberto, Silvia Bucci, Bernard Legras, Ajil Kottayil, Andrea Scoccione, and Stefano Ghisu
Atmos. Chem. Phys., 21, 7947–7961, https://doi.org/10.5194/acp-21-7947-2021, https://doi.org/10.5194/acp-21-7947-2021, 2021
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A lidar was used in Palau from February–March 2016. Clouds were observed peaking at 3 km below the high cold-point tropopause (CPT). Their occurrence was linked with cold anomalies, while in warm cases, cirrus clouds were restricted to 5 km below the CPT. Thin subvisible cirrus (SVC) near the CPT had distinctive characteristics. They were linked to wave-induced cold anomalies. Back trajectories are mostly compatible with convective outflow, while some distinctive SVC may originate in situ.
Edward Gryspeerdt, Tom Goren, and Tristan W. P. Smith
Atmos. Chem. Phys., 21, 6093–6109, https://doi.org/10.5194/acp-21-6093-2021, https://doi.org/10.5194/acp-21-6093-2021, 2021
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Cloud responses to aerosol are time-sensitive, but this development is rarely observed. This study uses isolated aerosol perturbations from ships to measure this development and shows that macrophysical (width, cloud fraction, detectability) and microphysical (droplet number) properties of ship tracks vary strongly with time since emission, background cloud and meteorological state. This temporal development should be considered when constraining aerosol–cloud interactions with observations.
Tianmeng Chen, Zhanqing Li, Ralph A. Kahn, Chuanfeng Zhao, Daniel Rosenfeld, Jianping Guo, Wenchao Han, and Dandan Chen
Atmos. Chem. Phys., 21, 6199–6220, https://doi.org/10.5194/acp-21-6199-2021, https://doi.org/10.5194/acp-21-6199-2021, 2021
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A convective cloud identification process is developed using geostationary satellite data from Himawari-8.
Convective cloud fraction is generally larger before noon and smaller in the afternoon under polluted conditions, but megacities and complex topography can influence the pattern.
A robust relationship between convective cloud and aerosol loading is found. This pattern varies with terrain height and is modulated by varying thermodynamic, dynamical, and humidity conditions during the day.
Ulrike Proske, Verena Bessenbacher, Zane Dedekind, Ulrike Lohmann, and David Neubauer
Atmos. Chem. Phys., 21, 5195–5216, https://doi.org/10.5194/acp-21-5195-2021, https://doi.org/10.5194/acp-21-5195-2021, 2021
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Ice crystals falling out of one cloud can initiate freezing in a second cloud below. We estimate the occurrence frequency of this natural cloud seeding over Switzerland from satellite data and sublimation calculations. We find that such situations with an ice cloud above another cloud are frequent and that the falling crystals survive the fall between two clouds in a significant number of cases, suggesting that natural cloud seeding is an important phenomenon over Switzerland.
Joseph Sedlar, Adele Igel, and Hagen Telg
Atmos. Chem. Phys., 21, 4149–4167, https://doi.org/10.5194/acp-21-4149-2021, https://doi.org/10.5194/acp-21-4149-2021, 2021
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.
Kevin M. Smalley and Anita D. Rapp
Atmos. Chem. Phys., 21, 2765–2779, https://doi.org/10.5194/acp-21-2765-2021, https://doi.org/10.5194/acp-21-2765-2021, 2021
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We use satellite observations of shallow cumulus clouds to investigate the influence of cloud size on the ratio of cloud water path to rainwater (WRR) in different environments. For a fixed temperature and relative humidity, WRR increases with cloud size, but it varies little with aerosols. These results imply that increasing WRR with rising temperature relates not only to deeper clouds but also to more frequent larger clouds.
Iris-Amata Dion, Cyrille Dallet, Philippe Ricaud, Fabien Carminati, Thibaut Dauhut, and Peter Haynes
Atmos. Chem. Phys., 21, 2191–2210, https://doi.org/10.5194/acp-21-2191-2021, https://doi.org/10.5194/acp-21-2191-2021, 2021
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Ice in the tropopause has a strong radiative effect on climate. The amount of ice injected (∆IWC) up to the tropical tropopause layer has been shown to be the highest over the Maritime Continent (MC), a region that includes Indonesia. ∆IWC is studied over islands and sea of the MC. Space-borne observations of ice, precipitation and lightning are used to estimate ∆IWC and are compared to ∆IWC estimated from the ERA5 reanalyses. It is shown that Java is the area of the greatest ∆IWC over the MC.
Claudia J. Stubenrauch, Giacomo Caria, Sofia E. Protopapadaki, and Friederike Hemmer
Atmos. Chem. Phys., 21, 1015–1034, https://doi.org/10.5194/acp-21-1015-2021, https://doi.org/10.5194/acp-21-1015-2021, 2021
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Tropical anvils formed by convective outflow play a crucial role in modulating the Earth’s energy budget and heat transport. To explore the relation between these anvils and convection, we built 3D radiative heating fields, based on machine learning employed on cloud and atmospheric properties from IR sounder and meteorological reanalyses, trained on lidar–radar retrievals. The 15-year time series reveals colder convective systems during warm periods, affecting the atmospheric heating structure.
Bida Jian, Jiming Li, Guoyin Wang, Yuxin Zhao, Yarong Li, Jing Wang, Min Zhang, and Jianping Huang
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1245, https://doi.org/10.5194/acp-2020-1245, 2021
Revised manuscript accepted for ACP
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We evaluate the performance of the AMIP6 model in simulating cloud albedo over marine subtropical regions and the impacts of different aerosol types and meteorological factors on the cloud albedo based on multiple satellite datasets and reanalysis data. The results show that AMIP6 shows moderate improvement over AMIP5 in simulating the monthly variation of cloud albedo, and changes in different aerosol types and meteorological factors can explained ~60 % of the changes in the cloud albedo.
Gregor Pante, Peter Knippertz, Andreas H. Fink, and Anke Kniffka
Atmos. Chem. Phys., 21, 35–55, https://doi.org/10.5194/acp-21-35-2021, https://doi.org/10.5194/acp-21-35-2021, 2021
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Seasonal rainfall amounts along the densely populated West African Guinea coast have been decreasing during the past 35 years, with recently accelerating trends. We find strong indications that this is in part related to increasing human air pollution in the region. Given the fast increase in emissions, the political implications of this work are significant. Reducing air pollution locally and regionally would mitigate an imminent health crisis and socio-economic damage from reduced rainfall.
Cristofer Jimenez, Albert Ansmann, Ronny Engelmann, David Donovan, Aleksey Malinka, Jörg Schmidt, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 20, 15247–15263, https://doi.org/10.5194/acp-20-15247-2020, https://doi.org/10.5194/acp-20-15247-2020, 2020
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A novel lidar method to study cloud microphysical properties (of liquid water clouds) and to study aerosol–cloud interaction (ACI) is developed and presented in this paper. In Part 1, the theoretical framework including an error analysis is given together with an overview of the aerosol information that the same lidar system can obtain. The ACI concept based on aerosol and cloud information is also explained. Applications of the proposed approach to lidar measurements are presented in Part 2.
Cristofer Jimenez, Albert Ansmann, Ronny Engelmann, David Donovan, Aleksey Malinka, Patric Seifert, Robert Wiesen, Martin Radenz, Zhenping Yin, Johannes Bühl, Jörg Schmidt, Boris Barja, and Ulla Wandinger
Atmos. Chem. Phys., 20, 15265–15284, https://doi.org/10.5194/acp-20-15265-2020, https://doi.org/10.5194/acp-20-15265-2020, 2020
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Part 2 presents the application of the dual-FOV polarization lidar technique introduced in Part 1. A lidar system was upgraded with a second polarization telescope, and it was deployed at the southernmost tip of South America. A comparison with alternative remote sensing techniques and the evaluation of the aerosol–cloud–wind relation in a convective boundary layer in pristine marine conditions are presented in two case studies, demonstrating the potential of the approach for ACI studies.
Johannes Quaas, Antti Arola, Brian Cairns, Matthew Christensen, Hartwig Deneke, Annica M. L. Ekman, Graham Feingold, Ann Fridlind, Edward Gryspeerdt, Otto Hasekamp, Zhanqing Li, Antti Lipponen, Po-Lun Ma, Johannes Mülmenstädt, Athanasios Nenes, Joyce E. Penner, Daniel Rosenfeld, Roland Schrödner, Kenneth Sinclair, Odran Sourdeval, Philip Stier, Matthias Tesche, Bastiaan van Diedenhoven, and Manfred Wendisch
Atmos. Chem. Phys., 20, 15079–15099, https://doi.org/10.5194/acp-20-15079-2020, https://doi.org/10.5194/acp-20-15079-2020, 2020
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Anthropogenic pollution particles – aerosols – serve as cloud condensation nuclei and thus increase cloud droplet concentration and the clouds' reflection of sunlight (a cooling effect on climate). This Twomey effect is poorly constrained by models and requires satellite data for better quantification. The review summarizes the challenges in properly doing so and outlines avenues for progress towards a better use of aerosol retrievals and better retrievals of droplet concentrations.
Hwayoung Jeoung, Guosheng Liu, Kwonil Kim, Gyuwon Lee, and Eun-Kyoung Seo
Atmos. Chem. Phys., 20, 14491–14507, https://doi.org/10.5194/acp-20-14491-2020, https://doi.org/10.5194/acp-20-14491-2020, 2020
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Radar and radiometer observations were used to study cloud liquid and snowfall in three types of snow clouds. While near-surface and shallow clouds have an area fraction of 90 %, deep clouds contribute half of the total snowfall volume. Deeper clouds have heavier snowfall, although cloud liquid is equally abundant in all three cloud types. The skills of a GMI Bayesian algorithm are examined. Snowfall in deep clouds may be reasonably retrieved, but it is challenging for near-surface clouds.
Juan Huo, Yufang Tian, Xue Wu, Congzheng Han, Bo Liu, Yongheng Bi, Shu Duan, and Daren Lyu
Atmos. Chem. Phys., 20, 14377–14392, https://doi.org/10.5194/acp-20-14377-2020, https://doi.org/10.5194/acp-20-14377-2020, 2020
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A detailed analysis of ice cloud physical properties is presented based on 4 years of surface Ka-band radar measurements in Beijing, where the summer oceanic monsoon from the ocean and winter continental monsoon prevail alternately. More than 6000 ice cloud clusters were studied to investigate their physical properties, such as height, horizontal extent, temperature dependence and origination type, which can serve as a reference for parameterization and characterization in global climate models.
Jie Gong, Xiping Zeng, Dong L. Wu, S. Joseph Munchak, Xiaowen Li, Stefan Kneifel, Davide Ori, Liang Liao, and Donifan Barahona
Atmos. Chem. Phys., 20, 12633–12653, https://doi.org/10.5194/acp-20-12633-2020, https://doi.org/10.5194/acp-20-12633-2020, 2020
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This work provides a novel way of using polarized passive microwave measurements to study the interlinked cloud–convection–precipitation processes. The magnitude of differences between polarized radiances is found linked to ice microphysics (shape, size, orientation and density), mesoscale dynamic and thermodynamic structures, and surface precipitation. We conclude that passive sensors with multiple polarized channel pairs may serve as cheaper and useful substitutes for spaceborne radar sensors.
Johannes Mohrmann, Robert Wood, Tianle Yuan, Hua Song, Ryan Eastman, and Lazaros Oreopoulos
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1026, https://doi.org/10.5194/acp-2020-1026, 2020
Revised manuscript accepted for ACP
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Observations of marine boundary layer conditions are composited by cloud type, based on a new classification dataset. It is found that two cloud types, representing regions of clustered and suppressed low-level clouds, occur in very similar large-scale conditions, but are distinguished from each other by considering low-level circulation and surface wind fields, validating prior results from modelling.
Feng Zhang, Qiu-Run Yu, Jia-Li Mao, Chen Dan, Yanyu Wang, Qianshan He, Tiantao Cheng, Chunhong Chen, Dongwei Liu, and Yanping Gao
Atmos. Chem. Phys., 20, 11799–11808, https://doi.org/10.5194/acp-20-11799-2020, https://doi.org/10.5194/acp-20-11799-2020, 2020
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In this work, we make the three main contributions. (1) We reveal the remarkable differences in the geographical distributions of cirrus over the Tibetan Plateau regarding the cloud top height. (2) The orography, gravity wave, and deep convection determine the formation of cirrus with a cloud top below 9, at 9–12, and above 12 km, respectively. (3) It is the first time the contributions of the Tibetan Plateau to the presence of cirrus on a regional scale are discussed.
Adeyemi A. Adebiyi, Paquita Zuidema, Ian Chang, Sharon P. Burton, and Brian Cairns
Atmos. Chem. Phys., 20, 11025–11043, https://doi.org/10.5194/acp-20-11025-2020, https://doi.org/10.5194/acp-20-11025-2020, 2020
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Over the southeast Atlantic, interactions between the low-level clouds and the overlying smoke aerosols have previously been highlighted, but no study has yet focused on the presence of the mid-level clouds that complicate the aerosol–cloud interactions. Here we show that these optically thin super-cooled mid-level clouds are relatively common, and they frequently occur at the top of the smoke layer between August and October with significant radiative impacts on the low-level clouds.
Haoran Li, Jussi Tiira, Annakaisa von Lerber, and Dmitri Moisseev
Atmos. Chem. Phys., 20, 9547–9562, https://doi.org/10.5194/acp-20-9547-2020, https://doi.org/10.5194/acp-20-9547-2020, 2020
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A method for classifying rimed and unrimed snow based on X- and Ka-band Doppler radar measurements is developed and applied to synergetic radar observations collected during BAECC 2014. The results show that the radar-observed melting layer properties are highly related to the precipitation intensity. The previously reported bright band sagging is mainly connected to the increase in precipitation intensity, while riming plays a secondary role.
Yulan Hong and Larry Di Girolamo
Atmos. Chem. Phys., 20, 8267–8291, https://doi.org/10.5194/acp-20-8267-2020, https://doi.org/10.5194/acp-20-8267-2020, 2020
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Cloud phase plays a crucial role in Earth radiation budget but is not well understood. Using A-Train satellite observations, this study provides climatological studies of cloud phase characteristics over Southeast Asia on multiple meteorological scales. Results show that ice, liquid, and ice over liquid clouds display distinct spatial heterogeneity and spectral radiance features. The intraseasonal and interannual behaviors of cloud phases are useful to track the MJO and ENSO.
Scott E. Giangrande, Dié Wang, and David B. Mechem
Atmos. Chem. Phys., 20, 7489–7507, https://doi.org/10.5194/acp-20-7489-2020, https://doi.org/10.5194/acp-20-7489-2020, 2020
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The Amazon basin experiences prolific and diverse cloud conditions that are strongly influenced by (and influence via feedbacks) seasonal shifts in the local conditions and larger-scale atmospheric circulations. The primary atmospheric regimes observed during a heavily instrumented 2-year Amazon deployment are classified. We assess the potential atmospheric controls on convective clouds, precipitation, and the propensity for these regimes to promote extremes in precipitation.
Josué Gehring, Annika Oertel, Étienne Vignon, Nicolas Jullien, Nikola Besic, and Alexis Berne
Atmos. Chem. Phys., 20, 7373–7392, https://doi.org/10.5194/acp-20-7373-2020, https://doi.org/10.5194/acp-20-7373-2020, 2020
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In this study, we analyse how large-scale meteorological conditions influenced the local enhancement of snowfall during an intense precipitation event in Korea. We used atmospheric models, weather radars and snowflake images. We found out that a rising airstream in the warm sector of the low pressure system associated to this event influenced the evolution of snowfall. This study highlights the importance of interactions between large and local scales in this intense precipitation event.
Timothy W. Juliano and Zachary J. Lebo
Atmos. Chem. Phys., 20, 7125–7138, https://doi.org/10.5194/acp-20-7125-2020, https://doi.org/10.5194/acp-20-7125-2020, 2020
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In this study, we use a machine learning method to examine the relationship between synoptic-scale changes in the North Pacific High structure and maritime cloud properties. Our novel approach suggests that there is a wide range (>30 W m−2, ~20 % of magnitude) of possible shortwave cloud radiative effect that is a clear function of the circulation pattern. We hope that this work will help improve fundamental understanding of the sensitivity of the climate system to various warm-cloud regimes.
Alyson Douglas and Tristan L'Ecuyer
Atmos. Chem. Phys., 20, 6225–6241, https://doi.org/10.5194/acp-20-6225-2020, https://doi.org/10.5194/acp-20-6225-2020, 2020
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Aerosols, or small, suspended droplets in the atmosphere, are released from anthropogenic activity and interact with warm clouds, leading to changes in the clouds' brightness and size. Our study evaluates how aerosols alter warm clouds and their ability to cool the Earth's surface. We find aerosols make clouds brighter and grow larger in the atmosphere; however, the cooling effect due to whiter, brighter clouds is 5 times the cooling due to an increased extent.
Elena Ruiz-Donoso, André Ehrlich, Michael Schäfer, Evelyn Jäkel, Vera Schemann, Susanne Crewell, Mario Mech, Birte Solveig Kulla, Leif-Leonard Kliesch, Roland Neuber, and Manfred Wendisch
Atmos. Chem. Phys., 20, 5487–5511, https://doi.org/10.5194/acp-20-5487-2020, https://doi.org/10.5194/acp-20-5487-2020, 2020
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Mixed-phase clouds, formed of water droplets and ice crystals, appear frequently in Arctic regions. Characterizing the distribution of liquid water and ice inside the cloud appropriately is important because it influences the cloud's impact on the surface temperature. In this study, we combined images of the cloud top with measurements inside the cloud to analyze in detail the 3D spatial distribution of liquid and ice in two mixed-phase clouds occurring under different meteorological scenarios.
Tatiana Nomokonova, Kerstin Ebell, Ulrich Löhnert, Marion Maturilli, and Christoph Ritter
Atmos. Chem. Phys., 20, 5157–5173, https://doi.org/10.5194/acp-20-5157-2020, https://doi.org/10.5194/acp-20-5157-2020, 2020
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This paper presents an influence of water vapor anomalies on cloud properties and their radiative effect at Ny-Ålesund. The study is based on a 2.5-year active and passive cloud observation and a radiative transfer model. The results show that moist and dry conditions are related to strong changes in cloud occurrence, phase partitioning, water path, and, consequently, modulate the surface radiative budget.
Kalliopi Artemis Voudouri, Elina Giannakaki, Mika Komppula, and Dimitris Balis
Atmos. Chem. Phys., 20, 4427–4444, https://doi.org/10.5194/acp-20-4427-2020, https://doi.org/10.5194/acp-20-4427-2020, 2020
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In this paper we present the variability in cirrus cloud properties using a PollyXT Raman lidar over high and tropical latitudes. The kind of information presented here can be rather useful in the cirrus parameterisations required as input to radiative transfer models and can be a complementary tool for satellite products that cannot provide cloud vertical structure.
Anna Possner, Ryan Eastman, Frida Bender, and Franziska Glassmeier
Atmos. Chem. Phys., 20, 3609–3621, https://doi.org/10.5194/acp-20-3609-2020, https://doi.org/10.5194/acp-20-3609-2020, 2020
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Cloud water content and the number of droplets inside clouds covary with boundary layer depth. This covariation may amplify the change in water content due to a change in droplet number inferred from long-term observations. Taking this into account shows that the change in water content for increased droplet number in observations and high-resolution simulations agrees in shallow boundary layers. Meanwhile, deep boundary layers are under-sampled in process-scale simulations and observations.
Xiaojian Zheng, Baike Xi, Xiquan Dong, Timothy Logan, Yuan Wang, and Peng Wu
Atmos. Chem. Phys., 20, 3483–3501, https://doi.org/10.5194/acp-20-3483-2020, https://doi.org/10.5194/acp-20-3483-2020, 2020
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The continental low-level stratiform cloud susceptibilities to aerosols were investigated under different absorptive aerosol regimes. The weakly absorbing aerosols, which are more hygroscopic, can better activate as cloud condensation nuclei. The favorable thermodynamic condition enhances the cloud susceptibility, while the cloud-layer heating effect induced by strongly absorbing aerosols dampens the cloud susceptibility. Overall, the clouds are more susceptible to the weakly absorbing aerosols.
Rosa Gierens, Stefan Kneifel, Matthew D. Shupe, Kerstin Ebell, Marion Maturilli, and Ulrich Löhnert
Atmos. Chem. Phys., 20, 3459–3481, https://doi.org/10.5194/acp-20-3459-2020, https://doi.org/10.5194/acp-20-3459-2020, 2020
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Multiyear statistics of persistent low-level mixed-phase clouds observed at an Arctic fjord environment in Svalbard are presented. The effects the local boundary layer (i.e. the fjords' wind climate and surface coupling), regional wind direction, and seasonality have on the cloud occurrence and properties are evaluated using a synergy of ground-based remote sensing methods and auxiliary data. The phenomena considered were found to modify the amount of liquid and ice in the studied clouds.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Peter Knippertz, Marco Gaetani, Julian Quinting, Sebastian Sippel, and Roland Vogt
Atmos. Chem. Phys., 20, 3415–3438, https://doi.org/10.5194/acp-20-3415-2020, https://doi.org/10.5194/acp-20-3415-2020, 2020
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Fog and low clouds (FLCs) are an essential but poorly understood element of Namib regional climate. Here, a satellite-based data set of FLCs in central Namib, reanalysis data, and back trajectories are used to systematically analyze conditions when FLCs occur. Synoptic-scale mechanisms are identified that influence the formation of FLCs and the onshore advection of marine boundary-layer air masses. The findings lead to a new conceptual model of mechanisms that drive FLC variability in the Namib.
Claudia Unglaub, Karoline Block, Johannes Mülmenstädt, Odran Sourdeval, and Johannes Quaas
Atmos. Chem. Phys., 20, 2407–2418, https://doi.org/10.5194/acp-20-2407-2020, https://doi.org/10.5194/acp-20-2407-2020, 2020
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In cloud research, it is necessary to classify clouds. The World Meteorological Organization proposes distinguishing stratiform and cumuliform clouds in three altitude layers. The paper explains why previous approaches to classify clouds fail for many applications and proposes a new classification on the basis of new approaches for satellite retrievals to derive cloud-base height, in combination with cloud inhomogeneity. It is demonstrated that this discriminates cloud characteristics well.
Diego Villanueva, Bernd Heinold, Patric Seifert, Hartwig Deneke, Martin Radenz, and Ina Tegen
Atmos. Chem. Phys., 20, 2177–2199, https://doi.org/10.5194/acp-20-2177-2020, https://doi.org/10.5194/acp-20-2177-2020, 2020
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Spaceborne retrievals of cloud phase were analysed together with an atmospheric composition model to assess the global frequency of ice and liquid clouds. This analysis showed that at equal temperature the average occurrence of ice clouds increases for higher dust mixing ratios on a day-to-day basis in the middle and high latitudes. This indicates that mineral dust may have a strong impact on the occurrence of ice clouds even in remote areas.
Yilun Chen, Guangcan Chen, Chunguang Cui, Aoqi Zhang, Rong Wan, Shengnan Zhou, Dongyong Wang, and Yunfei Fu
Atmos. Chem. Phys., 20, 1131–1145, https://doi.org/10.5194/acp-20-1131-2020, https://doi.org/10.5194/acp-20-1131-2020, 2020
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The vertical evolution of the cloud effective radius reflects the precipitation-forming process. We developed an algorithm for retrieving it based on objective cloud-cluster identification rather than the subjective polygon of the conventional method. The profile shows completely different morphologies in different life stages of the cloud cluster, which is important in the characterization of the formation of precipitation and the temporal evolution of microphysical processes.
Amir Erfanian and Rong Fu
Atmos. Chem. Phys., 19, 15199–15216, https://doi.org/10.5194/acp-19-15199-2019, https://doi.org/10.5194/acp-19-15199-2019, 2019
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An eastward advection of dry and warm air in spring was identified as a major drought onset mechanism over the US Great Plains (GP). Further breakdown of the zonal advection into the dynamic versus thermodynamic contributions revealed dominance of the latter in the tropospheric drying observed during the onset of GP 2011 and 2012 droughts. The dependence of thermodynamic advection on moisture gradient links the spring precipitation in the Rockies and US southwest to the GP summer precipitation.
Artem G. Feofilov and Claudia J. Stubenrauch
Atmos. Chem. Phys., 19, 13957–13972, https://doi.org/10.5194/acp-19-13957-2019, https://doi.org/10.5194/acp-19-13957-2019, 2019
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Clouds play an important role in the energy budget of the planet: optically thick clouds reflect the incoming solar radiation leading to cooling of the Earth, while thinner clouds act as
greenhouse filmspreventing escape of the Earth’s infrared radiation to space. Satellite observations provide a continuous survey of clouds over the whole globe. In this work, we use a combination of two space-borne sounders to retrieve and analyse the characteristics of diurnal variation of high-level clouds.
Nils Madenach, Cintia Carbajal Henken, René Preusker, Odran Sourdeval, and Jürgen Fischer
Atmos. Chem. Phys., 19, 13535–13546, https://doi.org/10.5194/acp-19-13535-2019, https://doi.org/10.5194/acp-19-13535-2019, 2019
Kadiri Saikranthi, Basivi Radhakrishna, Thota Narayana Rao, and Sreedharan Krishnakumari Satheesh
Atmos. Chem. Phys., 19, 10423–10432, https://doi.org/10.5194/acp-19-10423-2019, https://doi.org/10.5194/acp-19-10423-2019, 2019
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Recent studies have shown that simulation of monsoons can be improved with an exact representation of SST–precipitation relationship. The vertical structure of precipitation with SST is distinctly different over the Arabian Sea than over the Bay of Bengal. The reflectivity profiles show variation with SST over the Arabian Sea and do not show considerable variation with SST over the Bay of Bengal. The variations in reflectivity profiles seem to originate at the cloud formation stage itself.
Ralf Bennartz, Frank Fell, Claire Pettersen, Matthew D. Shupe, and Dirk Schuettemeyer
Atmos. Chem. Phys., 19, 8101–8121, https://doi.org/10.5194/acp-19-8101-2019, https://doi.org/10.5194/acp-19-8101-2019, 2019
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The Greenland Ice Sheet (GrIS) is rapidly melting. Snowfall is the only source of ice mass over the GrIS. We use satellite observations to assess how much snow on average falls over the GrIS and what the annual cycle and spatial distribution of snowfall is. We find the annual mean snowfall over the GrIS inferred from CloudSat to be 34 ± 7.5 cm yr−1 liquid equivalent.
Andrew Geiss and Roger Marchand
Atmos. Chem. Phys., 19, 7547–7565, https://doi.org/10.5194/acp-19-7547-2019, https://doi.org/10.5194/acp-19-7547-2019, 2019
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The 13-year trends in cloud occurrence, observed by NASA's Multi-angle Imaging SpectroRadiometer, over the world's extratropical ocean basins are compared to trends in meteorological variables. We identify several patterns of changing cloud occurrence that correspond to specific patterns in trending meteorology. We find that many of these trends are related to changes in major modes of climate variability.
Constantino Listowski, Julien Delanoë, Amélie Kirchgaessner, Tom Lachlan-Cope, and John King
Atmos. Chem. Phys., 19, 6771–6808, https://doi.org/10.5194/acp-19-6771-2019, https://doi.org/10.5194/acp-19-6771-2019, 2019
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Using satellite cloud products we investigate the supercooled liquid-water (SLW) distribution Antarctic-wide for the first time. We demonstrate differences between the monthly evolution of the marine low-level mixed-phase clouds and that of the marine low-level pure SLW clouds. In addition to the temperature and sea ice fraction as factors explaining the low-level liquid-cloud seasonal cycle, ice nuclei emissions from open water may also be driving the mixed-phase cloud monthly evolution.
Iris-Amata Dion, Philippe Ricaud, Peter Haynes, Fabien Carminati, and Thibaut Dauhut
Atmos. Chem. Phys., 19, 6459–6479, https://doi.org/10.5194/acp-19-6459-2019, https://doi.org/10.5194/acp-19-6459-2019, 2019
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Water vapour and ice cirrus clouds near the tropical tropopause layer (TTL) have a strong radiative impact on climate. Based on space-borne observations, we have developed a model linking ice in the upper troposphere from the Microwave Limb Sounder (MLS) to precipitation in the troposphere from the Tropical Rainfall Measurement Mission (TRMM). Our study quantifies the amount of ice injected into the TTL by deep convection over tropical lands and oceans by investigating the diurnal cycle of ice.
Alyson Douglas and Tristan L'Ecuyer
Atmos. Chem. Phys., 19, 6251–6268, https://doi.org/10.5194/acp-19-6251-2019, https://doi.org/10.5194/acp-19-6251-2019, 2019
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Aerosols are released by natural and human activities. When aerosols encounter clouds they interact in what is known as the indirect effect. Brighter clouds are expected due to the microphysical response; however, certain environments can trigger a modified response. Limits on the stability, humidity, and cloud thickness are applied regionally to investigate local cloud responses to aerosol, resulting in a range of indirect effects that would result in significant cooling or slight warming.
Andrew I. Barrett, Christopher D. Westbrook, John C. Nicol, and Thorwald H. M. Stein
Atmos. Chem. Phys., 19, 5753–5769, https://doi.org/10.5194/acp-19-5753-2019, https://doi.org/10.5194/acp-19-5753-2019, 2019
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We use radars at three wavelengths to study cloud properties. The full Doppler spectra (rather than calculated averages of the spectra) are compared for the radars. This allows us to estimate the size and number of ice particles within the cloud. By following the evolution of the ice particles, we observe a region where particles rapidly and consistently increase in size. The observations suggest that these large particles form through interlocking of branched arms of smaller ice particles.
Edward Gryspeerdt, Tom Goren, Odran Sourdeval, Johannes Quaas, Johannes Mülmenstädt, Sudhakar Dipu, Claudia Unglaub, Andrew Gettelman, and Matthew Christensen
Atmos. Chem. Phys., 19, 5331–5347, https://doi.org/10.5194/acp-19-5331-2019, https://doi.org/10.5194/acp-19-5331-2019, 2019
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The liquid water path (LWP) is the strongest control on cloud albedo, such that a small change in LWP can have a large radiative impact. By changing the droplet number concentration (Nd) aerosols may be able to change the LWP, but the sign and magnitude of the effect is unclear. This work uses satellite data to investigate the relationship between Nd and LWP at a global scale and in response to large aerosol perturbations, suggesting that a strong decrease in LWP at high Nd may be overestimated.
David P. Duda, Sarah T. Bedka, Patrick Minnis, Douglas Spangenberg, Konstantin Khlopenkov, Thad Chee, and William L. Smith Jr.
Atmos. Chem. Phys., 19, 5313–5330, https://doi.org/10.5194/acp-19-5313-2019, https://doi.org/10.5194/acp-19-5313-2019, 2019
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We use one year (2012) of satellite imagery obtained from two NASA research satellites, Terra and Aqua, to detect linear contrail coverage and to estimate their physical properties over the Northern Hemisphere. The satellite-derived properties are compared with results collected from the same sensors in 2006 to estimate whether the impact of contrail coverage on climate has changed. The study is the first of its kind to measure contrail properties over a near-global scale from satellite imagery.
Emily M. McCullough, James R. Drummond, and Thomas J. Duck
Atmos. Chem. Phys., 19, 4595–4614, https://doi.org/10.5194/acp-19-4595-2019, https://doi.org/10.5194/acp-19-4595-2019, 2019
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Very thin (<10 m) laminations within Arctic clouds have been observed in all seasons using the Canadian Network for the Detection of Atmospheric Change (CANDAC) Rayleigh–Mie–Raman lidar (CRL) at the Polar Environment Atmospheric Research Laboratory (PEARL; Eureka, Nunavut, Canadian High Arctic). The laminations can last longer than 24 h and are often associated with precipitation and atmospheric stability. This has implications for our understanding of cloud internal structure and processes.
Tatiana Nomokonova, Kerstin Ebell, Ulrich Löhnert, Marion Maturilli, Christoph Ritter, and Ewan O'Connor
Atmos. Chem. Phys., 19, 4105–4126, https://doi.org/10.5194/acp-19-4105-2019, https://doi.org/10.5194/acp-19-4105-2019, 2019
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In this study, properties of clouds at the French–German Arctic research station in Ny-Ålesund are related to in-cloud thermodynamic conditions. The dataset used was collected within the Arctic Amplification project with a set of active and passive remote instruments. The results are compared with a model output. Significant divergence in observations and modelling of single-layer ice and mixed-phase clouds was found.
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Short summary
Fog and low clouds (FLCs) are an essential but poorly understood component of Namib-region climate. This study uses observations from multiple satellite platforms and ground-based measurements to coherently characterize Namib-region FLC patterns. Findings concerning the seasonal cycle of the vertical structure and the diurnal cycle of FLCs lead to a new conceptual model of the spatiotemporal dynamics of FLCs in the Namib and help to improve the understanding of underlying processes.
Fog and low clouds (FLCs) are an essential but poorly understood component of Namib-region...
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