Article
Environmental Sciences
Tamas Varnai, Alexander Marshak
Summary: This study examines cloud-related variations of atmospheric aerosols in partly cloudy regions, utilizing a statistical analysis of a global dataset to reveal key findings such as larger near-cloud enhancements in lidar backscatter over land than ocean. The research also shows that the mean lidar backscatter is higher near clouds due to local processes associated with individual clouds rather than large-scale variations in meteorological conditions, contributing to a better understanding of aerosol-cloud-radiation interactions.
Article
Meteorology & Atmospheric Sciences
I. R. Julsrud, T. Storelvmo, M. Schulz, K. O. Moseid, M. Wild
Summary: This study investigates the variations of surface solar radiation (SSR) and its influencing factors, including cloud cover and aerosols, as well as the simulation of SSR by Earth system models (ESMs). The observational study reveals that cloud cover has a dampening effect on SSR variations, while aerosol emissions are the main cause of SSR trends in four regions. The simulation results show that current ESMs are unable to fully replicate the observed variations, except for the European region.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Geosciences, Multidisciplinary
Yang Cao, Minghuai Wang, Daniel Rosenfeld, Yannian Zhu, Yuan Liang, Zhoukun Liu, Heming Bai
Summary: The study found that aerosols have a significant impact on cloud fraction over the East Coast of the United States. Factors such as cloud droplet number concentrations, cloud geometrical thickness, lower tropospheric stability, and relative humidity at 950 hPa were identified as major cloud controlling parameters. While there was no significant trend in annual-mean cloud fraction, a decline in cloud droplet number concentrations alone could lead to a relative decline in cloud fraction.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Tao Huang, Yannian Zhu, Daniel Rosenfeld, Yuanjian Yang, David H. Y. Lam, W. H. Leung, Harry F. Lee, Jack C. H. Cheng, Steve H. L. Yim
Summary: The regime dependence of aerosol-cloud interaction has been explored through idealized cloud-resolving models and observations. The activation of cloud condensation nuclei (CCN) is limited by particle numbers in clean conditions, while updraft velocities play a crucial role in polluted regimes. Warm rain suppression is significantly enhanced over inland areas. These findings are supported by satellite retrievals and LiDAR observations.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Chiao-Wei Chang, Wei-Ting Chen, Yi-Chun Chen
Summary: The study investigated the sensitivity of warm clouds to aerosols in East Asia from 2006 to 2010 and found that precipitating clouds are more susceptible to aerosols compared to non-precipitating clouds. Cloud liquid water path increased with aerosols for precipitating clouds but decreased for non-precipitating clouds, showing differences in cloud responses to aerosols based on environmental factors.
Article
Geosciences, Multidisciplinary
Tom Goren, Odran Sourdeval, Jan Kretzschmar, Johannes Quaas
Summary: This paper examines the impact of cloud albedo morphology, which reflects cloud heterogeneity, on radiative forcing due to aerosol-cloud interactions. The estimation of radiative forcing relies on the assumption of cloud homogeneity within a given scene, but this assumption is no longer valid when satellite data is spatially aggregated. As a result, there is an overestimation of radiative forcing, particularly in heterogeneous scenes, which can reach up to 50%. The study also suggests that cloud albedo enhancement is most effective in homogeneous scenes, emphasizing the importance of considering cloud albedo homogeneity in marine cloud brightening strategies.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Prashantha Kumar Kemmannu, Busnur Rachotappa Manjunatha
Summary: This study investigates the impact of aerosols on the precipitation and cloud microphysical characteristics associated with Western Disturbances (WDs) in February 2016. The findings show that aerosols have a stimulating effect on rainfall during the dissipating phase. However, the model predictions of precipitation location and intensity have some discrepancies.
Article
Meteorology & Atmospheric Sciences
Renju Nandan, M. Venkat Ratnam, V. Ravi Kiran, Dinesh N. Naik
Summary: In this study, an observational approach is used to estimate the aerosol-cloud interaction (ACI) in water clouds over an Indian region. The analysis shows a decrease in correlation between aerosol and cloud optical depths as the height above cloud base increases. The observed patterns of high and low ACI support the seasonal variations of water cloud occurrence.
ATMOSPHERIC RESEARCH
(2022)
Article
Environmental Sciences
Ling Zou, Sabine Griessbach, Lars Hoffmann, Reinhold Spang
Summary: This study investigates the occurrence and variability of stratospheric ice clouds (SICs) in the tropics and at midlatitudes by analyzing their relationships with tropopause temperature, double tropopauses, UTLS clouds, gravity waves, and stratospheric aerosols. The results show that SICs mainly occur in the tropics and are strongly associated with double tropopauses and UTLS clouds.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Review
Geochemistry & Geophysics
Ralph A. A. Kahn, Elisabeth Andrews, Charles A. A. Brock, Mian Chin, Graham Feingold, Andrew Gettelman, Robert C. C. Levy, Daniel M. M. Murphy, Athanasios Nenes, Jeffrey R. R. Pierce, Thomas Popp, Jens Redemann, Andrew M. M. Sayer, Arlindo M. M. da Silva, Larisa Sogacheva, Philip Stier
Summary: Aerosol forcing uncertainty remains the largest climate forcing uncertainty and has not diminished significantly in the past 20 years. This review summarizes the contributions made by satellite observations, atmospheric measurements, modeling, and data assimilation to reduce the uncertainty in aerosol forcing of climate. The review highlights the need for systematic aircraft in situ measurements, suborbital programs, and integration of satellite observations, measurements, and modeling to reduce the persistent uncertainty in aerosol climate forcing.
REVIEWS OF GEOPHYSICS
(2023)
Article
Environmental Sciences
Qianqian Song, Zhibo Zhang, Hongbin Yu, Jasper F. Kok, Claudia Di Biagio, Samuel Albani, Jianyu Zheng, Jiachen Ding
Summary: The role of mineral dust aerosol in the global radiative energy budget is important. In this study, a size-resolved dust direct radiative effect (DRE) dataset is derived based on satellite observations, and the sensitivity of DRE to dust particle size distribution and optical properties is investigated. The results show that dust refractive index and shape have a significant impact on DRE.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Environmental Sciences
Jian Guan, Bohan Jin, Yizhe Ding, Wen Wang, Guoxiang Li, Pubu Ciren
Summary: Formaldehyde is a significant carcinogenic air pollutant, but the lack of global surface concentration monitoring hinders research on outdoor pollution. Utilizing neural networks, the study estimated the global surface HCHO concentration in 2019, with an average concentration of 2.30 μg/m³ globally and highest concentrations in regions such as the Amazon Basin and Northern China. The study provides the first dataset on global surface HCHO concentration and adds confidence intervals to the results, paving the way for further research on global ambient HCHO health risks and economic losses.
Article
Geosciences, Multidisciplinary
Xiaoli Zhou, Jianhao Zhang, Graham Feingold
Summary: The study reveals that sea surface temperature has a dominant control on the cloud albedo of marine low clouds, while aerosol perturbations also play an important role. Regions with higher local sea surface temperature are more conducive to aerosol-induced darkening clouds, while regions with lower local sea surface temperature are more conducive to aerosol-induced brightening clouds.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Yang Ou, Lei Li, Zhengqiang Li, Ying Zhang, Oleg Dubovik, Yevgeny Derimian, Cheng Chen, David Fuertes, Yisong Xie, Anton Lopatin, Fabrice Ducos, Zongren Peng
Summary: Remote sensing observations were used to analyze aerosol components in the North China Plain, showing higher black carbon mass concentration in Shanxi compared to Beijing, while brown carbon mass concentrations were higher in Beijing. Additionally, fine ammonium sulfate-like particles were three times lower in Beijing than in Shanxi.
Article
Environmental Sciences
Ke Gui, Huizheng Che, Yu Zheng, Yaqiang Wang, Lei Zhang, Hujia Zhao, Lei Li, Junting Zhong, Wenrui Yao, Xiaoye Zhang
Summary: This study utilized a long-term dataset to analyze the global climatology of seasonal AODs, with results showing different types and sizes of aerosols contribute differently to the global aerosol impact. The study also found significant declines in seasonal TAOD in most regions globally, with small-size AOD and spherical AOD contributing most significantly to the decrease.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Geosciences, Multidisciplinary
Eva Pauli, Jan Cermak, Adriaan J. Teuling
Summary: Understanding the factors driving the occurrence of fog and low stratus (FLS) clouds is crucial for various aspects including transportation, ecosystems, and climate models. A study on the nighttime FLS occurrence over the Landes forest in France from 2006 to 2015 using satellite and reanalysis data reveals a significant enhancement of FLS occurrence over the forest compared to surrounding areas, particularly in summer and fall. The findings suggest that factors such as lower wind speed, lower temperatures, and biovolatile organic compounds may contribute to the development of FLS over the forest.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Steven D. Miller, Yoo-Jeong Noh, Lewis D. Grasso, Curtis J. Seaman, Alexander Ignatov, Andrew K. Heidinger, SungHyun Nam, William E. Line, Boris Petrenko
Summary: Marine boundary layer (MBL) clouds are important for Earth's radiation balance, and satellite remote sensing is the most practical method for collecting information about these clouds. Recent comparisons have shown that there are instances where too many MBL clouds are being analyzed as false alarms in operational algorithms. This study explores the physical basis for these issues and confirms the false alarm mechanism through radiative transfer simulations. The findings suggest that localized to regional-scale biases may exist in nocturnal MBL cloud descriptions, potentially impacting downstream environmental parameters such as sea surface temperature climate records. Increasing the frequency of nighttime visible observations and refining infrared-based algorithms in areas prone to false alarm could help mitigate these issues.
EARTH AND SPACE SCIENCE
(2022)
Article
Engineering, Ocean
John M. Haynes, Yoo-Jeong Noh, Steven D. Miller, Katherine D. Haynes, Imme Ebert-Uphoff, Andrew Heidinger
Summary: This work develops pixel-based machine learning methods to detect low clouds in the atmosphere, with a focus on improving detection in multilayer cloud situations. The random forest and neural network models show similar performances, significantly improving the probability of detection of low clouds, especially for scenes resembling cirrus clouds.
JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY
(2022)
Article
Meteorology & Atmospheric Sciences
Eva Pauli, Jan Cermak, Hendrik Andersen
Summary: Knowledge about fog and low stratus (FLS) cloud patterns and life cycles is crucial for traffic safety, solar energy production, and analysis of cloud processes in the climate system. This study utilizes logistic regression to analyze FLS formation and dissipation times in central Europe based on a satellite dataset spanning 10 years. Results indicate a geographical dependence of FLS formation and dissipation on topography, with mountainous areas experiencing overnight formation and morning dissipation, while river valleys show a shift towards formation after sunrise and dissipation in the afternoon. Additionally, seasonal patterns reveal similar FLS formation and dissipation times in winter-autumn and spring-summer, albeit with longer durations in the former two seasons.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Environmental Sciences
Lukas Zipfel, Hendrik Andersen, Jan Cermak
Summary: In this study, satellite observations and atmospheric reanalysis data are used to predict changes in cloud liquid water path (LWP) in the marine boundary layer clouds (MBLCs) in the Southeast Atlantic using a regional machine learning model. The study identifies precipitation fraction, cloud top height, and cloud droplet number concentration (N-d) as important cloud state predictors for LWP, while dynamical proxies and sea surface temperature (SST) are found to be the most important environmental predictors. The study also finds a positive nonlinear relationship between LWP and N-d, with a weaker sensitivity at high cloud droplet concentrations, and this relationship is dependent on other predictors in the model, such as precipitation and SST.
Article
Environmental Sciences
A. M. Fischer, K. M. Strassmann, M. Croci-Maspoli, A. M. Hama, R. Knutti, S. Kotlarski, C. Schar, C. Schnadt Poberaj, N. Ban, M. Bavay, U. Beyerle, D. N. Bresch, S. Bronnimann, P. Burlando, A. Casanueva, S. Fatichi, I Feigenwinter, E. M. Fischer, M. Hirschi, M. A. Liniger, C. Marty, I Medhaug, N. Peleg, M. Pickl, C. C. Raible, J. Rajczak, O. Rossler, S. C. Scherrer, C. Schwierz, S. Seneviratne, M. Skelton, S. L. Sorland, C. Spirig, F. Tschurr, J. Zeder, E. M. Zubler
Summary: To address climate change, Switzerland has developed user-oriented climate change scenarios through close collaboration between academia and administration. These scenarios show that Switzerland will face dry summers, heavy precipitation, more hot days, and snow-scarce winters in the future. Approximately half of these changes could be alleviated by strong global mitigation efforts by the mid-century.
Article
Environmental Sciences
Andrew K. Heidinger, Michael J. Foster, Kenneth R. Knapp, Timothy J. Schmit
Summary: The study used data from the ABI on GOES-16 and GOES-17 to calibrate the visible channels on past geostationary imagers. A new calibration method was developed based on the stability of the integrated full-disk reflectance, offering a simple and complementary approach to existing calibration techniques.
Article
Meteorology & Atmospheric Sciences
Michael J. Foster, Coda Phillips, Andrew K. Heidinger, Eva E. Borbas, Yue Li, W. Paul Menzel, Andi Walther, Elisabeth Weisz
Summary: A new version 6.0 of the PATMOS-x multidecadal cloud record is now available, showing improved stability and consistency compared to the previous version. This is achieved through the addition of multidimensional variables, constraining cloud retrievals to available radiometric bands, and incorporating data from the HIRS instrument.
JOURNAL OF CLIMATE
(2023)
Article
Environmental Sciences
Yue Yang, Jan Cermak, Kangzhuo Yang, Eva Pauli, Yunping Chen
Summary: This study examines the relationships between major land cover types and aerosol optical depth (AOD) in an urban area using high-resolution satellite data. The findings demonstrate that the distribution of aerosols varies significantly in both time and space, and urban and built-up land contribute significantly to aerosol formation.
Article
Environmental Sciences
Yoo-Jeong Noh, John M. Haynes, Steven D. Miller, Curtis J. Seaman, Andrew K. Heidinger, Jeffrey Weinrich, Mark S. Kulie, Mattie Niznik, Brandon J. Daub
Summary: This study develops a statistical algorithm for retrieving three-dimensional cloud structure information using satellite data. The algorithm has been improved based on feedback from aviation users, and the products are evaluated using multiple satellite data sources and surface measurements. This provides a valuable approach for displaying key information about clouds.
Article
Geosciences, Multidisciplinary
Marius Egli, Sebastian Sippel, Angeline G. Pendergrass, Iris de Vries, Reto Knutti
Summary: Future changes in precipitation have significant impacts on societies worldwide, but uncertainties persist due to limited observational coverage, climate variability, and model disagreement. In this study, we propose a new method to reconstruct seasonally averaged zonal precipitation using climate model simulations and sparse rain-gauge data. The reconstructed precipitation shows a signal likely caused by human influence, as it exceeds the variability range of pre-industrial control simulations and is consistent with historical simulations driven by external forcing.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
E. M. Fischer, U. Beyerle, L. Bloin-Wibe, C. Gessner, V. Humphrey, F. Lehner, A. G. Pendergrass, S. Sippel, J. Zeder, R. Knutti
Summary: Recent temperature extremes have exceeded previous records and it is questioned whether these intense events could have been predicted using climate models or if there are greater intensities to come. This study demonstrates how an ensemble boosting approach can generate physically plausible storylines for hotter heatwaves, indicating the possibility of even greater intensities in places like Greater Chicago and Paris. Combining different lines of evidence and process understanding is crucial in establishing confidence in such extreme events and informing planning for future unprecedented intensities.
NATURE COMMUNICATIONS
(2023)
Article
Geosciences, Multidisciplinary
Anna L. Merrifield, Lukas Brunner, Ruth Lorenz, Vincent Humphrey, Reto Knutti
Summary: With the increase in the number of models in the CMIP archive, guidance is needed to interpret and utilize the abundance of newly available climate information. This study addresses the issues of model dependence and model subselection, providing methods to navigate the CMIP6 and multi-model ensembles. The proposed frameworks, based on model dependence and cost function minimization, offer a novel and transparent approach to select models and guide users in the increasingly complex CMIP landscape.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Geosciences, Multidisciplinary
Iris Elisabeth de Vries, Sebastian Sippel, Angeline Greene Pendergrass, Reto Knutti
Summary: This study uses statistical method ridge regression to detect forced changes in mean and extreme precipitation. The results show that forced changes can be detected in the observational datasets, but the detection may vary depending on the dataset used and the uncertainty associated with the observations.
EARTH SYSTEM DYNAMICS
(2023)
Review
Environmental Sciences
Daniela I. V. Domeisen, Elfatih A. B. Eltahir, Erich M. M. Fischer, Reto Knutti, Sarah E. E. Perkins-Kirkpatrick, Christoph Schar, Sonia I. I. Seneviratne, Antje Weisheimer, Heini Wernli
Summary: Heatwaves pose a major threat to human health and ecosystems, and predicting them is crucial for preparedness. Current capabilities allow for skillful prediction of heatwaves on daily to weekly timescales, but become challenging beyond a few weeks. However, tendencies for above-average temperatures can still be estimated. Future projections suggest that heatwaves will become more frequent, persistent, and intense worldwide, with amplified trends in mid-latitudes due to soil drying. There will also be an increased occurrence of humid heatwaves, particularly in southern Asia. Improving heatwave prediction and projection requires a better understanding of relevant drivers and their model representation.
NATURE REVIEWS EARTH & ENVIRONMENT
(2023)
