Articles | Volume 19, issue 23
https://doi.org/10.5194/acp-19-15023-2019
© Author(s) 2019. 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-19-15023-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Dec 2019
Research article |
| 11 Dec 2019
| 11 Dec 2019
How should we aggregate data? Methods accounting for the numerical distributions, with an assessment of aerosol optical depth
GESTAR, Universities Space Research Association, Columbia, MD, USA
NASA Goddard Space Flight Center, Greenbelt, MD, USA
Kirk D. Knobelspiesse
NASA Goddard Space Flight Center, Greenbelt, MD, USA
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R. C. Levy, S. Mattoo, L. A. Munchak, L. A. Remer, A. M. Sayer, F. Patadia, and N. C. Hsu
Atmos. Meas. Tech., 6, 2989–3034, https://doi.org/10.5194/amt-6-2989-2013, https://doi.org/10.5194/amt-6-2989-2013, 2013
Xin Xi, Jun Wang, Zhendong Lu, Andrew M. Sayer, Jaehwa Lee, Robert C. Levy, Yujie Wang, Alexei Lyapustin, Hongqing Liu, Istvan Laszlo, Changwoo Ahn, Omar Torres, Sabur Abdullaev, James Limbacher, and Ralph A. Kahn
Atmos. Chem. Phys., 25, 7403–7429, https://doi.org/10.5194/acp-25-7403-2025, https://doi.org/10.5194/acp-25-7403-2025, 2025
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The Aralkum Desert is challenging for aerosol retrieval due to its bright, heterogeneous, and dynamic surfaces and the lack of in situ constraints on aerosol properties. The performance and consistency of satellite algorithms in observing Aralkum-generated saline dust remain unknown. This study compares multisensor UVAI (ultraviolet aerosol index), AOD (aerosol optical depth), and ALH (aerosol layer height) products and reveals inconsistencies and potential biases over the Aral Sea basin.
Andrew M. Sayer, Brian Cairns, Kirk D. Knobelspiesse, Luca Lelli, Chamara Rajapakshe, Scott E. Giangrande, Gareth E. Thomas, and Damao Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2025-2005, https://doi.org/10.5194/egusphere-2025-2005, 2025
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Satellites can estimate cloud height in several ways: two include a thermal technique (colder clouds being higher up), and another looking at colours of light that oxygen in the atmosphere absorbs (darker clouds being lower down). It can also be measured (from ground or space) by radar and lidar. We compare satellite data we developed using the oxygen method with other estimates to help us refine our technique.
Sean R. Foley, Kirk D. Knobelspiesse, Andrew M. Sayer, Meng Gao, James Hays, and Judy Hoffman
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Meng Gao, Bryan A. Franz, Peng-Wang Zhai, Kirk Knobelspiesse, Andrew M. Sayer, Xiaoguang Xu, J. Vanderlei Martins, Brian Cairns, Patricia Castellanos, Guangliang Fu, Neranga Hannadige, Otto Hasekamp, Yongxiang Hu, Amir Ibrahim, Frederick Patt, Anin Puthukkudy, and P. Jeremy Werdell
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Neranga K. Hannadige, Peng-Wang Zhai, Meng Gao, Yongxiang Hu, P. Jeremy Werdell, Kirk Knobelspiesse, and Brian Cairns
Atmos. Meas. Tech., 16, 5749–5770, https://doi.org/10.5194/amt-16-5749-2023, https://doi.org/10.5194/amt-16-5749-2023, 2023
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We evaluated the impact of three ocean optical models with different numbers of free parameters on the performance of an aerosol and ocean color remote sensing algorithm using the multi-angle polarimeter (MAP) measurements. It was demonstrated that the three- and seven-parameter bio-optical models can be used to accurately represent both open and coastal waters, whereas the one-parameter model has smaller retrieval uncertainty over open water.
Meng Gao, Kirk Knobelspiesse, Bryan A. Franz, Peng-Wang Zhai, Brian Cairns, Xiaoguang Xu, and J. Vanderlei Martins
Atmos. Meas. Tech., 16, 2067–2087, https://doi.org/10.5194/amt-16-2067-2023, https://doi.org/10.5194/amt-16-2067-2023, 2023
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Multi-angle polarimetric measurements have been shown to greatly improve the remote sensing capability of aerosols and help atmospheric correction for ocean color retrievals. However, the uncertainty correlations among different measurement angles have not been well characterized. In this work, we provided a practical framework to evaluate the impact of the angular uncertainty correlation in retrieval results and a method to directly estimate correlation strength from retrieval residuals.
Edward Gryspeerdt, Adam C. Povey, Roy G. Grainger, Otto Hasekamp, N. Christina Hsu, Jane P. Mulcahy, Andrew M. Sayer, and Armin Sorooshian
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Andrew M. Sayer, Luca Lelli, Brian Cairns, Bastiaan van Diedenhoven, Amir Ibrahim, Kirk D. Knobelspiesse, Sergey Korkin, and P. Jeremy Werdell
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Santiago Gassó and Kirk D. Knobelspiesse
Atmos. Chem. Phys., 22, 13581–13605, https://doi.org/10.5194/acp-22-13581-2022, https://doi.org/10.5194/acp-22-13581-2022, 2022
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Atmospheric particles interact with light resulting in observable optical polarization. Thus, we can learn about their composition from space. New satellite sensor technology measures full polarization of reflected sunlight. This paper considers circular polarization, an overlooked category of polarization with distinctive features that could bring new insights. We review existing literature and make novel computations to consider this previously underappreciated category of polarization.
Meng Gao, Kirk Knobelspiesse, Bryan A. Franz, Peng-Wang Zhai, Andrew M. Sayer, Amir Ibrahim, Brian Cairns, Otto Hasekamp, Yongxiang Hu, Vanderlei Martins, P. Jeremy Werdell, and Xiaoguang Xu
Atmos. Meas. Tech., 15, 4859–4879, https://doi.org/10.5194/amt-15-4859-2022, https://doi.org/10.5194/amt-15-4859-2022, 2022
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In this work, we assessed the pixel-wise retrieval uncertainties on aerosol and ocean color derived from multi-angle polarimetric measurements. Standard error propagation methods are used to compute the uncertainties. A flexible framework is proposed to evaluate how representative these uncertainties are compared with real retrieval errors. Meanwhile, to assist operational data processing, we optimized the computational speed to evaluate the retrieval uncertainties based on neural networks.
Meng Gao, Bryan A. Franz, Kirk Knobelspiesse, Peng-Wang Zhai, Vanderlei Martins, Sharon Burton, Brian Cairns, Richard Ferrare, Joel Gales, Otto Hasekamp, Yongxiang Hu, Amir Ibrahim, Brent McBride, Anin Puthukkudy, P. Jeremy Werdell, and Xiaoguang Xu
Atmos. Meas. Tech., 14, 4083–4110, https://doi.org/10.5194/amt-14-4083-2021, https://doi.org/10.5194/amt-14-4083-2021, 2021
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Multi-angle polarimetric measurements can retrieve accurate aerosol properties over complex atmosphere and ocean systems; however, most retrieval algorithms require high computational costs. We propose a deep neural network (NN) forward model to represent the radiative transfer simulation of coupled atmosphere and ocean systems and then conduct simultaneous aerosol and ocean color retrievals on AirHARP measurements. The computational acceleration is 103 times with CPU or 104 times with GPU.
Kirk Knobelspiesse, Amir Ibrahim, Bryan Franz, Sean Bailey, Robert Levy, Ziauddin Ahmad, Joel Gales, Meng Gao, Michael Garay, Samuel Anderson, and Olga Kalashnikova
Atmos. Meas. Tech., 14, 3233–3252, https://doi.org/10.5194/amt-14-3233-2021, https://doi.org/10.5194/amt-14-3233-2021, 2021
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We assessed atmospheric aerosol and ocean surface wind speed remote sensing capability with NASA's Multi-angle Imaging SpectroRadiometer (MISR), using synthetic data and a Bayesian inference technique called generalized nonlinear retrieval analysis (GENRA). We found success using three aerosol parameters plus wind speed. This shows that MISR can perform an atmospheric correction for the Moderate Resolution Imaging Spectroradiometer (MODIS) on the same spacecraft (Terra).
Jens Redemann, Robert Wood, Paquita Zuidema, Sarah J. Doherty, Bernadette Luna, Samuel E. LeBlanc, Michael S. Diamond, Yohei Shinozuka, Ian Y. Chang, Rei Ueyama, Leonhard Pfister, Ju-Mee Ryoo, Amie N. Dobracki, Arlindo M. da Silva, Karla M. Longo, Meloë S. Kacenelenbogen, Connor J. Flynn, Kristina Pistone, Nichola M. Knox, Stuart J. Piketh, James M. Haywood, Paola Formenti, Marc Mallet, Philip Stier, Andrew S. Ackerman, Susanne E. Bauer, Ann M. Fridlind, Gregory R. Carmichael, Pablo E. Saide, Gonzalo A. Ferrada, Steven G. Howell, Steffen Freitag, Brian Cairns, Brent N. Holben, Kirk D. Knobelspiesse, Simone Tanelli, Tristan S. L'Ecuyer, Andrew M. Dzambo, Ousmane O. Sy, Greg M. McFarquhar, Michael R. Poellot, Siddhant Gupta, Joseph R. O'Brien, Athanasios Nenes, Mary Kacarab, Jenny P. S. Wong, Jennifer D. Small-Griswold, Kenneth L. Thornhill, David Noone, James R. Podolske, K. Sebastian Schmidt, Peter Pilewskie, Hong Chen, Sabrina P. Cochrane, Arthur J. Sedlacek, Timothy J. Lang, Eric Stith, Michal Segal-Rozenhaimer, Richard A. Ferrare, Sharon P. Burton, Chris A. Hostetler, David J. Diner, Felix C. Seidel, Steven E. Platnick, Jeffrey S. Myers, Kerry G. Meyer, Douglas A. Spangenberg, Hal Maring, and Lan Gao
Atmos. Chem. Phys., 21, 1507–1563, https://doi.org/10.5194/acp-21-1507-2021, https://doi.org/10.5194/acp-21-1507-2021, 2021
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Southern Africa produces significant biomass burning emissions whose impacts on regional and global climate are poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) is a 5-year NASA investigation designed to study the key processes that determine these climate impacts. The main purpose of this paper is to familiarize the broader scientific community with the ORACLES project, the dataset it produced, and the most important initial findings.
Cheng Chen, Oleg Dubovik, David Fuertes, Pavel Litvinov, Tatyana Lapyonok, Anton Lopatin, Fabrice Ducos, Yevgeny Derimian, Maurice Herman, Didier Tanré, Lorraine A. Remer, Alexei Lyapustin, Andrew M. Sayer, Robert C. Levy, N. Christina Hsu, Jacques Descloitres, Lei Li, Benjamin Torres, Yana Karol, Milagros Herrera, Marcos Herreras, Michael Aspetsberger, Moritz Wanzenboeck, Lukas Bindreiter, Daniel Marth, Andreas Hangler, and Christian Federspiel
Earth Syst. Sci. Data, 12, 3573–3620, https://doi.org/10.5194/essd-12-3573-2020, https://doi.org/10.5194/essd-12-3573-2020, 2020
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Aerosol products obtained from POLDER/PARASOL processed by the GRASP algorithm have been released. The entire archive of PARASOL/GRASP aerosol products is evaluated against AERONET and compared with MODIS (DT, DB and MAIAC), as well as PARASOL/Operational products. PARASOL/GRASP aerosol products provide spectral 443–1020 nm AOD correlating well with AERONET with a maximum bias of 0.02. Finally, GRASP shows capability to derive detailed spectral properties, including aerosol absorption.
Marc Mallet, Fabien Solmon, Pierre Nabat, Nellie Elguindi, Fabien Waquet, Dominique Bouniol, Andrew Mark Sayer, Kerry Meyer, Romain Roehrig, Martine Michou, Paquita Zuidema, Cyrille Flamant, Jens Redemann, and Paola Formenti
Atmos. Chem. Phys., 20, 13191–13216, https://doi.org/10.5194/acp-20-13191-2020, https://doi.org/10.5194/acp-20-13191-2020, 2020
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This paper presents numerical simulations using two regional climate models to study the impact of biomass fire plumes from central Africa on the radiative balance of this region. The results indicate that biomass fires can either warm the regional climate when they are located above low clouds or cool it when they are located above land. They can also alter sea and land surface temperatures by decreasing solar radiation at the surface. Finally, they can also modify the atmospheric dynamics.
Nick Schutgens, Andrew M. Sayer, Andreas Heckel, Christina Hsu, Hiren Jethva, Gerrit de Leeuw, Peter J. T. Leonard, Robert C. Levy, Antti Lipponen, Alexei Lyapustin, Peter North, Thomas Popp, Caroline Poulsen, Virginia Sawyer, Larisa Sogacheva, Gareth Thomas, Omar Torres, Yujie Wang, Stefan Kinne, Michael Schulz, and Philip Stier
Atmos. Chem. Phys., 20, 12431–12457, https://doi.org/10.5194/acp-20-12431-2020, https://doi.org/10.5194/acp-20-12431-2020, 2020
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We intercompare 14 different datasets of satellite observations of aerosol. Such measurements are challenging but also provide the best opportunity to globally observe an atmospheric component strongly related to air pollution and climate change. Our study shows that most datasets perform similarly well on a global scale but that locally errors can be quite different. We develop a technique to estimate satellite errors everywhere, even in the absence of surface reference data.
Kirk Knobelspiesse, Henrique M. J. Barbosa, Christine Bradley, Carol Bruegge, Brian Cairns, Gao Chen, Jacek Chowdhary, Anthony Cook, Antonio Di Noia, Bastiaan van Diedenhoven, David J. Diner, Richard Ferrare, Guangliang Fu, Meng Gao, Michael Garay, Johnathan Hair, David Harper, Gerard van Harten, Otto Hasekamp, Mark Helmlinger, Chris Hostetler, Olga Kalashnikova, Andrew Kupchock, Karla Longo De Freitas, Hal Maring, J. Vanderlei Martins, Brent McBride, Matthew McGill, Ken Norlin, Anin Puthukkudy, Brian Rheingans, Jeroen Rietjens, Felix C. Seidel, Arlindo da Silva, Martijn Smit, Snorre Stamnes, Qian Tan, Sebastian Val, Andrzej Wasilewski, Feng Xu, Xiaoguang Xu, and John Yorks
Earth Syst. Sci. Data, 12, 2183–2208, https://doi.org/10.5194/essd-12-2183-2020, https://doi.org/10.5194/essd-12-2183-2020, 2020
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The Aerosol Characterization from Polarimeter and Lidar (ACEPOL) field campaign is a resource for the next generation of spaceborne multi-angle polarimeter (MAP) and lidar missions. Conducted in the fall of 2017 from the Armstrong Flight Research Center in Palmdale, California, four MAP instruments and two lidars were flown on the high-altitude ER-2 aircraft over a variety of scene types and ground assets. Data are freely available to the public and useful for algorithm development and testing.
Meng Gao, Peng-Wang Zhai, Bryan A. Franz, Kirk Knobelspiesse, Amir Ibrahim, Brian Cairns, Susanne E. Craig, Guangliang Fu, Otto Hasekamp, Yongxiang Hu, and P. Jeremy Werdell
Atmos. Meas. Tech., 13, 3939–3956, https://doi.org/10.5194/amt-13-3939-2020, https://doi.org/10.5194/amt-13-3939-2020, 2020
Daniel J. Miller, Michal Segal-Rozenhaimer, Kirk Knobelspiesse, Jens Redemann, Brian Cairns, Mikhail Alexandrov, Bastiaan van Diedenhoven, and Andrzej Wasilewski
Atmos. Meas. Tech., 13, 3447–3470, https://doi.org/10.5194/amt-13-3447-2020, https://doi.org/10.5194/amt-13-3447-2020, 2020
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A neural network (NN) is developed and used to retrieve cloud microphysical properties from multiangular and multispectral polarimetric remote sensing observations. The NN is applied to research scanning polarimeter (RSP) observations obtained during the ORACLES field campaign and compared to other co-located remote sensing retrievals of cloud effective radius and optical thickness. A NN approach can advance more complex iterative search retrieval algorithms by providing a quick initial guess.
Larisa Sogacheva, Thomas Popp, Andrew M. Sayer, Oleg Dubovik, Michael J. Garay, Andreas Heckel, N. Christina Hsu, Hiren Jethva, Ralph A. Kahn, Pekka Kolmonen, Miriam Kosmale, Gerrit de Leeuw, Robert C. Levy, Pavel Litvinov, Alexei Lyapustin, Peter North, Omar Torres, and Antti Arola
Atmos. Chem. Phys., 20, 2031–2056, https://doi.org/10.5194/acp-20-2031-2020, https://doi.org/10.5194/acp-20-2031-2020, 2020
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The typical lifetime of a single satellite platform is on the order of 5–15 years; thus, for climate studies the usage of multiple satellite sensors should be considered.
Here we introduce and evaluate a monthly AOD merged product and AOD global and regional time series for the period 1995–2017 created from 12 individual satellite AOD products, which provide a long-term perspective on AOD changes over different regions of the globe.
Guangliang Fu, Otto Hasekamp, Jeroen Rietjens, Martijn Smit, Antonio Di Noia, Brian Cairns, Andrzej Wasilewski, David Diner, Felix Seidel, Feng Xu, Kirk Knobelspiesse, Meng Gao, Arlindo da Silva, Sharon Burton, Chris Hostetler, John Hair, and Richard Ferrare
Atmos. Meas. Tech., 13, 553–573, https://doi.org/10.5194/amt-13-553-2020, https://doi.org/10.5194/amt-13-553-2020, 2020
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In this paper, we present aerosol retrieval results from the ACEPOL (Aerosol Characterization from Polarimeter and Lidar) campaign, which was a joint initiative between NASA and SRON (the Netherlands Institute for Space Research). We perform aerosol retrievals from different multi-angle polarimeters employed during the ACEPOL campaign and evaluate them against ground-based AERONET measurements and High Spectral Resolution Lidar-2 (HSRL-2) measurements.
Andrew M. Sayer, Yves Govaerts, Pekka Kolmonen, Antti Lipponen, Marta Luffarelli, Tero Mielonen, Falguni Patadia, Thomas Popp, Adam C. Povey, Kerstin Stebel, and Marcin L. Witek
Atmos. Meas. Tech., 13, 373–404, https://doi.org/10.5194/amt-13-373-2020, https://doi.org/10.5194/amt-13-373-2020, 2020
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Satellite measurements of the Earth are routinely processed to estimate useful quantities; one example is the amount of atmospheric aerosols (which are particles such as mineral dust, smoke, volcanic ash, or sea spray). As with all measurements and inferred quantities, there is some degree of uncertainty in this process.
There are various methods to estimate these uncertainties. A related question is the following: how reliable are these estimates? This paper presents a method to assess them.
Zachary Fasnacht, Alexander Vasilkov, David Haffner, Wenhan Qin, Joanna Joiner, Nickolay Krotkov, Andrew M. Sayer, and Robert Spurr
Atmos. Meas. Tech., 12, 6749–6769, https://doi.org/10.5194/amt-12-6749-2019, https://doi.org/10.5194/amt-12-6749-2019, 2019
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The anisotropy of Earth's surface reflection plays an important role in satellite-based retrievals of cloud, aerosol, and trace gases. Most current ultraviolet and visible satellite retrievals utilize climatological surface reflectivity databases that do not account for surface anisotropy. The GLER concept was introduced to account for such features. Here we evaluate GLER for water surfaces by comparing with OMI measurements and show that it captures these surface anisotropy features.
Meng Gao, Peng-Wang Zhai, Bryan A. Franz, Yongxiang Hu, Kirk Knobelspiesse, P. Jeremy Werdell, Amir Ibrahim, Brian Cairns, and Alison Chase
Atmos. Meas. Tech., 12, 3921–3941, https://doi.org/10.5194/amt-12-3921-2019, https://doi.org/10.5194/amt-12-3921-2019, 2019
Andrew M. Sayer, N. Christina Hsu, Jaehwa Lee, Woogyung V. Kim, Sharon Burton, Marta A. Fenn, Richard A. Ferrare, Meloë Kacenelenbogen, Samuel LeBlanc, Kristina Pistone, Jens Redemann, Michal Segal-Rozenhaimer, Yohei Shinozuka, and Si-Chee Tsay
Atmos. Meas. Tech., 12, 3595–3627, https://doi.org/10.5194/amt-12-3595-2019, https://doi.org/10.5194/amt-12-3595-2019, 2019
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Aerosols are small particles in the atmosphere such as dust or smoke. They are routinely monitored by satellites due to their importance for climate and air quality. However aerosols above clouds are more difficult to monitor. This study describes an improvement to a technique to monitor light-absorbing aerosols above clouds from four Earth-orbiting satellite instruments. The improved method is evaluated using data from the ORACLES field campaign, which measured these aerosols from aircraft.
Marc Mallet, Pierre Nabat, Paquita Zuidema, Jens Redemann, Andrew Mark Sayer, Martin Stengel, Sebastian Schmidt, Sabrina Cochrane, Sharon Burton, Richard Ferrare, Kerry Meyer, Pablo Saide, Hiren Jethva, Omar Torres, Robert Wood, David Saint Martin, Romain Roehrig, Christina Hsu, and Paola Formenti
Atmos. Chem. Phys., 19, 4963–4990, https://doi.org/10.5194/acp-19-4963-2019, https://doi.org/10.5194/acp-19-4963-2019, 2019
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The model is able to represent LWP but not the LCF. AOD is consistent over the continent but also over ocean (ACAOD). Differences are observed in SSA due to the absence of internal mixing in ALADIN-Climate. A significant regional gradient of the forcing at TOA is observed. An intense positive forcing is simulated over Gabon. Results highlight the significant effect of enhanced moisture on BBA extinction. The surface dimming modifies the energy budget.
Kirk Knobelspiesse and Sreeja Nag
Atmos. Meas. Tech., 11, 3935–3954, https://doi.org/10.5194/amt-11-3935-2018, https://doi.org/10.5194/amt-11-3935-2018, 2018
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We test if small satellites flying in formation can be used for multi-angle aerosol remote sensing. So far, this has only been done with multiple views on one satellite. Single-view angle satellites flying in formation are a technically feasible alternative, although with different geometries. Using Bayesian information content analysis, we find such satellites equally capable. For aerosol remote sensing, the number of viewing angles is the most important.
Daniel J. Miller, Zhibo Zhang, Steven Platnick, Andrew S. Ackerman, Frank Werner, Celine Cornet, and Kirk Knobelspiesse
Atmos. Meas. Tech., 11, 3689–3715, https://doi.org/10.5194/amt-11-3689-2018, https://doi.org/10.5194/amt-11-3689-2018, 2018
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Prior satellite comparisons of bispectral and polarimetric cloud droplet size retrievals exhibited systematic biases. However, similar airborne instrument retrievals have been found to be quite similar to one another. This study explains this discrepancy in terms of differing sensitivity to vertical profile, as well as spatial and angular resolution. This is accomplished by using a satellite retrieval simulator – an LES cloud model coupled to radiative transfer and cloud retrieval algorithms.
Andrew M. Sayer, N. Christina Hsu, Corey Bettenhausen, Robert E. Holz, Jaehwa Lee, Greg Quinn, and Paolo Veglio
Atmos. Meas. Tech., 10, 1425–1444, https://doi.org/10.5194/amt-10-1425-2017, https://doi.org/10.5194/amt-10-1425-2017, 2017
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The satellite instrument VIIRS is being used to carry on observations of the Earth made by older satellites like MODIS. Data sets created from these satellite observations depend on the quality of the satellite instruments' calibration. This paper describes a comparison between the calibration of these two sensors. MODIS is believed to be more reliable and so VIIRS is corrected to bring it in line with MODIS. These corrections are shown to improve the quality of VIIRS aerosol data.
Sharon P. Burton, Eduard Chemyakin, Xu Liu, Kirk Knobelspiesse, Snorre Stamnes, Patricia Sawamura, Richard H. Moore, Chris A. Hostetler, and Richard A. Ferrare
Atmos. Meas. Tech., 9, 5555–5574, https://doi.org/10.5194/amt-9-5555-2016, https://doi.org/10.5194/amt-9-5555-2016, 2016
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Retrievals of aerosol microphysics exist for ground-based, airborne, and future space-borne lidar measurements. We investigate the information content of a lidar measurement system, using only a forward model but no explicit inversion. The simplified aerosol used here is applicable as a best case for all retrievals in the absence of additional constraints. We report (1) information content of the measurements; (2) uncertainties on the retrieved parameters; and (3) sources of compensating errors.
A. M. Sayer, N. C. Hsu, and C. Bettenhausen
Atmos. Meas. Tech., 8, 5277–5288, https://doi.org/10.5194/amt-8-5277-2015, https://doi.org/10.5194/amt-8-5277-2015, 2015
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MODIS is a satellite sensor widely used in Earth science. Its scanning geometry results in a distortion called the ‘bow-tie effect’, which means that, depending on the location of a pixel relative to the satellite ground track, the size and shape of the pixel may be distorted. This affects data such as aerosol optical depth (AOD) derived from the measurements. This paper illustrates the bow-tie disortion’s effect on AOD and presents techniques to restore AOD data products to a more uniform grid
A. M. Sayer, N. C. Hsu, T. F. Eck, A. Smirnov, and B. N. Holben
Atmos. Chem. Phys., 14, 11493–11523, https://doi.org/10.5194/acp-14-11493-2014, https://doi.org/10.5194/acp-14-11493-2014, 2014
S. K. Ebmeier, A. M. Sayer, R. G. Grainger, T. A. Mather, and E. Carboni
Atmos. Chem. Phys., 14, 10601–10618, https://doi.org/10.5194/acp-14-10601-2014, https://doi.org/10.5194/acp-14-10601-2014, 2014
M. Chin, T. Diehl, Q. Tan, J. M. Prospero, R. A. Kahn, L. A. Remer, H. Yu, A. M. Sayer, H. Bian, I. V. Geogdzhayev, B. N. Holben, S. G. Howell, B. J. Huebert, N. C. Hsu, D. Kim, T. L. Kucsera, R. C. Levy, M. I. Mishchenko, X. Pan, P. K. Quinn, G. L. Schuster, D. G. Streets, S. A. Strode, O. Torres, and X.-P. Zhao
Atmos. Chem. Phys., 14, 3657–3690, https://doi.org/10.5194/acp-14-3657-2014, https://doi.org/10.5194/acp-14-3657-2014, 2014
R. C. Levy, S. Mattoo, L. A. Munchak, L. A. Remer, A. M. Sayer, F. Patadia, and N. C. Hsu
Atmos. Meas. Tech., 6, 2989–3034, https://doi.org/10.5194/amt-6-2989-2013, https://doi.org/10.5194/amt-6-2989-2013, 2013
Related subject area
Subject: Aerosols | Research Activity: Remote Sensing | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Discussion of the spectral slope of the lidar ratio between 355 and 1064 nm from multiwavelength Raman lidar observations
Observational constraints suggest a smaller effective radiative forcing from aerosol–cloud interactions
Analysis of a saline dust storm from the Aralkum Desert – Part 1: Consistency between multisensor satellite aerosol products
Retrieval of microphysical properties of dust aerosols from extinction, backscattering and depolarization lidar measurements using various particle scattering models
Fluorescence spectra of atmospheric aerosols
All-Sky Direct Aerosol Radiative Effects Estimated from Integrated A-Train Satellite Measurements
Invisible aerosol layers: improved lidar detection capabilities by means of laser-induced aerosol fluorescence
Wildfires heat the middle troposphere over the Himalayas and Tibetan Plateau during the peak of fire season
Characterization of aerosol optical depth (AOD) anomalies in September and October 2022 over Skukuza in South Africa
Technical note: Evolution of convective boundary layer height estimated by Ka-band continuous millimeter wave radar at Wuhan in central China
Evolution of aerosol optical depth over China in 2010–2024: increasing importance of meteorological influences
Trends in the erythemal radiant exposure from re-evaluated measurements (1976–2023) with biometers at Belsk, Poland, and their sources from corresponding ozone, aerosol, and cloud observations
Fluorescence properties of long-range-transported smoke: insights from five-channel lidar observations over Moscow during the 2023 wildfire season
Lidar estimates of birch pollen number, mass, and CCN-related concentrations
An observational estimate of Arctic UV-absorbing aerosol direct radiative forcing on instantaneous and climatic scales
Distinct effects of fine and coarse aerosols on microphysical processes of shallow-precipitation systems in summer over southern China
Increased number concentrations of small particles explain perceived stagnation in air quality over Korea
Atmospheric processing and aerosol aging responsible for observed increase in absorptivity of long-range transported smoke over the southeast Atlantic
Remote-sensing detectability of airborne Arctic dust
Regional transport of aerosols from Northern India and its impact on boundary layer dynamics and air quality over Chennai, a coastal megacity in Southern India
Investigating the link between mineral dust hematite content and intensive optical properties by means of lidar measurements and aerosol modelling
The role of refractive indices in measuring mineral dust with high-spectral-resolution infrared satellite sounders: application to the Gobi Desert
Influence of covariance of aerosol and meteorology on co-located precipitating and non-precipitating clouds over the Indo-Gangetic Plain
Light-absorbing black carbon and brown carbon components of smoke aerosol from DSCOVR EPIC measurements over North America and central Africa
The emission, transport, and impacts of the extreme Saharan dust storm of 2015
California wildfire smoke contributes to a positive atmospheric temperature anomaly over the western United States
Dust storms from the Taklamakan Desert significantly darken snow surface on surrounding mountains
Opposite effects of aerosols and meteorological parameters on warm clouds in two contrasting regions over eastern China
Effect of wind speed on marine aerosol optical properties over remote oceans with use of spaceborne lidar observations
Assessment of smoke plume height products derived from multisource satellite observations using lidar-derived height metrics for wildfires in the western US
A remote sensing algorithm for vertically resolved cloud condensation nuclei number concentrations from airborne and spaceborne lidar observations
Opinion: Aerosol remote sensing over the next 20 years
Monitoring biomass burning aerosol transport using CALIOP observations and reanalysis models: a Canadian wildfire event in 2019
Thermal infrared observations of a western United States biomass burning aerosol plume
A new look into the impacts of dust radiative effects on the energetics of tropical easterly waves
Wind-driven emissions of coarse-mode particles in an urban environment
Measurement report: Dust and anthropogenic aerosols' vertical distributions over northern China dense aerosols gathered at the top of the mixing layer
Climatological assessment of the vertically resolved optical and microphysical aerosol properties by lidar measurements, sun photometer, and in situ observations over 17 years at Universitat Politècnica de Catalunya (UPC) Barcelona
Aerosol optical depth climatology from the high-resolution MAIAC product over Europe: differences between major European cities and their surrounding environments
Impact of assimilating NOAA VIIRS aerosol optical depth (AOD) observations on global AOD analysis from the Copernicus Atmosphere Monitoring Service (CAMS)
Spectral dependence of birch and pine pollen optical properties using a synergy of lidar instruments
Validation activities of Aeolus wind products on the southeastern Iberian Peninsula
Thermal infrared dust optical depth and coarse-mode effective diameter over oceans retrieved from collocated MODIS and CALIOP observations
A comprehensive reappraisal of long-term aerosol characteristics, trends, and variability in Asia
Satellite (GOSAT-2 CAI-2) retrieval and surface (ARFINET) observations of aerosol black carbon over India
Spatiotemporal variation characteristics of global fires and their emissions
The (mis)identification of high-latitude dust events using remote sensing methods in the Yukon, Canada: a sub-daily variability analysis
Comparison of dust optical depth from multi-sensor products and MONARCH (Multiscale Online Non-hydrostatic AtmospheRe CHemistry) dust reanalysis over North Africa, the Middle East, and Europe
Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia
Satellite observations of smoke–cloud–radiation interactions over the Amazon rainforest
Moritz Haarig, Ronny Engelmann, Holger Baars, Benedikt Gast, Dietrich Althausen, and Albert Ansmann
Atmos. Chem. Phys., 25, 7741–7763, https://doi.org/10.5194/acp-25-7741-2025, https://doi.org/10.5194/acp-25-7741-2025, 2025
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The lidar ratio is an important quantity in aerosol typing. Its spectral slope contains information about the source region or transport paths of the observed aerosol. The extension to 1064 nm is a recent development led by our institute. We gathered previous observations and added new ones to provide the spectral slope for the most important aerosol types such as marine and continental aerosol, dust, smoke, and sulfate. We compared it to assumptions used for spaceborne backscatter lidars.
Chanyoung Park, Brian J. Soden, Ryan J. Kramer, Tristan S. L'Ecuyer, and Haozhe He
Atmos. Chem. Phys., 25, 7299–7313, https://doi.org/10.5194/acp-25-7299-2025, https://doi.org/10.5194/acp-25-7299-2025, 2025
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This study addresses the long-standing challenge of quantifying the impact of aerosol–cloud interactions. Using satellite observations, reanalysis data, and a "perfect-model" cross-validation, we show that explicitly accounting for aerosol–cloud droplet activation rates is key to accurately estimating ERFaci (effective radiative forcing due to aerosol–cloud interactions). Our results indicate a smaller and less uncertain ERFaci than previously assessed, implying the reduced role of aerosol–cloud interactions in shaping climate sensitivity.
Xin Xi, Jun Wang, Zhendong Lu, Andrew M. Sayer, Jaehwa Lee, Robert C. Levy, Yujie Wang, Alexei Lyapustin, Hongqing Liu, Istvan Laszlo, Changwoo Ahn, Omar Torres, Sabur Abdullaev, James Limbacher, and Ralph A. Kahn
Atmos. Chem. Phys., 25, 7403–7429, https://doi.org/10.5194/acp-25-7403-2025, https://doi.org/10.5194/acp-25-7403-2025, 2025
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The Aralkum Desert is challenging for aerosol retrieval due to its bright, heterogeneous, and dynamic surfaces and the lack of in situ constraints on aerosol properties. The performance and consistency of satellite algorithms in observing Aralkum-generated saline dust remain unknown. This study compares multisensor UVAI (ultraviolet aerosol index), AOD (aerosol optical depth), and ALH (aerosol layer height) products and reveals inconsistencies and potential biases over the Aral Sea basin.
Yuyang Chang, Qiaoyun Hu, Philippe Goloub, Thierry Podvin, Igor Veselovskii, Fabrice Ducos, Gaël Dubois, Masanori Saito, Anton Lopatin, Oleg Dubovik, and Cheng Chen
Atmos. Chem. Phys., 25, 6787–6821, https://doi.org/10.5194/acp-25-6787-2025, https://doi.org/10.5194/acp-25-6787-2025, 2025
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Our study retrieved dust aerosol microphysical properties from lidar measurements using different scattering models. Numeric simulations and real data applications revealed the importance of considering depolarization measurements and the superiority of the irregular–hexahedral model in the retrieval of dust aerosols from lidar measurements.
Jens Reichardt, Felix Lauermann, and Oliver Behrendt
Atmos. Chem. Phys., 25, 5857–5892, https://doi.org/10.5194/acp-25-5857-2025, https://doi.org/10.5194/acp-25-5857-2025, 2025
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Optical remote sensing systems, so-called lidars, are used to learn more about aerosols, which play an important role in atmospheric processes. The present study demonstrates that lidars, which measure the backscattering behavior of aerosols over the entire visible wavelength range, can increase our knowledge of the spatial and temporal occurrence of aerosol layers, the type of aerosol, and their interaction with clouds. The focus of the publication is on wildfire aerosol and Saharan dust.
Meloë S. F. Kacenelenbogen, Ralph Kuehn, Nandana Amarasinghe, Kerry Meyer, Edward Nowottnick, Mark Vaughan, Hong Chen, Sebastian Schmidt, Richard Ferrare, John Hair, Robert Levy, Hongbin Yu, Paquita Zuidema, Robert Holz, and Willem Marais
EGUsphere, https://doi.org/10.5194/egusphere-2025-1403, https://doi.org/10.5194/egusphere-2025-1403, 2025
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Aerosols perturb the radiation balance of the Earth-atmosphere system. To reduce the uncertainty in quantifying present-day climate change, we combine two satellite sensors and a model to assess the aerosol effects on radiation in all-sky conditions. Satellite-based and coincident aircraft measurements of aerosol radiative effects agree well over the Southeast Atlantic. This constitutes a crucial first evaluation before we apply our method to more years and regions of the world.
Benedikt Gast, Cristofer Jimenez, Albert Ansmann, Moritz Haarig, Ronny Engelmann, Felix Fritzsch, Athena A. Floutsi, Hannes Griesche, Kevin Ohneiser, Julian Hofer, Martin Radenz, Holger Baars, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 3995–4011, https://doi.org/10.5194/acp-25-3995-2025, https://doi.org/10.5194/acp-25-3995-2025, 2025
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In this study, we discuss the enhanced detection capabilities of a fluorescence lidar in the case of optically thin aerosol layers in the upper troposphere and lower stratosphere (UTLS) region. Our results suggest that such thin aerosol layers are not so rare in the UTLS and can potentially trigger and impact cirrus cloud formation through heterogeneous ice nucleation. By altering the microphysical cloud properties, this could affect clouds' evolution and lifetime and thus their climate effect.
Qiaomin Pei, Chuanfeng Zhao, Yikun Yang, Annan Chen, Zhiyuan Cong, Xin Wan, Haotian Zhang, and Guangming Wu
EGUsphere, https://doi.org/10.5194/egusphere-2025-1172, https://doi.org/10.5194/egusphere-2025-1172, 2025
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This study investigates smoke's impact on atmospheric warming over the Himalayan and Tibetan Plateau (HTP) using MODIS fire data, ground-based and satellite aerosol observations, and model simulations. It finds that smoke aerosols – predominantly concentrated between 6 and 8 km in the mid-troposphere over southern HTP – likely alter regional atmospheric stability by modifying the vertical temperature profile, as indicated by a reduced lapse rate.
Marion Ranaivombola, Nelson Bègue, Lucas Vaz Peres, Farahnaz Fazel-Rastgar, Venkataraman Sivakumar, Gisèle Krysztofiak, Gwenaël Berthet, Fabrice Jegou, Stuart Piketh, and Hassan Bencherif
Atmos. Chem. Phys., 25, 3519–3540, https://doi.org/10.5194/acp-25-3519-2025, https://doi.org/10.5194/acp-25-3519-2025, 2025
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From September to October 2022, the Biomass Burning Aerosol Campaign (BiBAC) in Kruger National Park revealed a significant aerosol loading linked to biomass burning activity, with southeastward transport over southern Africa and the southwestern Indian Ocean (SWIO) basin. The study revealed a predominance of biomass burning aerosols and two distinct transport mechanisms of aerosol plumes and CO, underscoring the importance of east-coast observations in understanding atmospheric dynamics.
Zirui Zhang, Kaiming Huang, Fan Yi, Wei Cheng, Fuchao Liu, Jian Zhang, and Yue Jia
Atmos. Chem. Phys., 25, 3347–3361, https://doi.org/10.5194/acp-25-3347-2025, https://doi.org/10.5194/acp-25-3347-2025, 2025
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The height of the convective boundary layer (CBLH) is related to our health due to its crucial role in pollutant dispersion. The variance of vertical velocity from millimeter wave cloud radar (MMCR) can accurately capture the diurnal evolution of the CBLH, due to a small blind range and less impact by the residual layer. The CBLH is affected by radiation, humidity, cloud, and precipitation; thus, the MMCR is suitable for monitoring the CBLH, owing to its observation capability in various weather conditions.
Cheng Fan, Gerrit de Leeuw, Xiaoxi Yan, Jiantao Dong, Hanqing Kang, Chengwei Fang, Zhengqiang Li, and Ying Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2025-880, https://doi.org/10.5194/egusphere-2025-880, 2025
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This study describes the analysis of time series of the MODIS-derived Aerosol Optical Depth (AOD) over China between 2010 and 2024. Emission reduction policy has been effective in reducing the AOD until 2018. Thereafter the overall reduction until the end of the study was very small due to unfavorable meteorological factors cancelling favorable anthropogenic effects which resulted in AOD increase during extended periods. The variations over different areas in China are discussed.
Agnieszka Czerwińska, Janusz Krzyścin, Janusz Jarosławski, Piotr S. Sobolewski, and Aleksander Pietruczuk
EGUsphere, https://doi.org/10.5194/egusphere-2025-1129, https://doi.org/10.5194/egusphere-2025-1129, 2025
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Excessive levels of ultraviolet solar radiation at the Earth's surface have been linked to several types of skin cancer. The world's longest record of solar radiation intensities causing harmful skin redness comes from observations at Belsk, Poland, between 1976 and 2023. In this century, the intensity of such radiation is stable, but 15 % higher than in the 1970s. This trend is due to the combined effects of a decrease in stratospheric ozone and an increase in cloud transparency before 2000.
Igor Veselovskii, Mikhail Korenskiy, Nikita Kasianik, Boris Barchunov, Qiaoyun Hu, Philippe Goloub, and Thierry Podvin
Atmos. Chem. Phys., 25, 1603–1615, https://doi.org/10.5194/acp-25-1603-2025, https://doi.org/10.5194/acp-25-1603-2025, 2025
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A fluorescence lidar was used to study transported Canadian smoke in May–September 2023. The fluorescence measurements were taken at five wavelengths. The results revealed that fluorescence capacity increases with altitude, suggesting a higher concentration of organic compounds in the upper troposphere and lower stratosphere than in the lower troposphere. The fluorescence spectra peaked in the 513 and 560 nm channels in smoke layers but decreased with wavelength in urban aerosols.
Maria Filioglou, Petri Tiitta, Xiaoxia Shang, Ari Leskinen, Pasi Ahola, Sanna Pätsi, Annika Saarto, Ville Vakkari, Uula Isopahkala, and Mika Komppula
Atmos. Chem. Phys., 25, 1639–1657, https://doi.org/10.5194/acp-25-1639-2025, https://doi.org/10.5194/acp-25-1639-2025, 2025
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Every year a vast number of people experience allergic reactions due to exposure to airborne pollen. These symptoms are concentration dependent; thus accurate information about the pollen load in the atmosphere is essential. Moreover, pollen grains and fragments of it are likely to contribute to cloud processes and suppress precipitation. Here, we estimate the concentration and cloud-relevant parameters of birch pollen in the atmosphere using observations from a PollyXT and a CL61 ceilometer.
Blake T. Sorenson, Jianglong Zhang, Jeffrey S. Reid, and Peng Xian
EGUsphere, https://doi.org/10.5194/egusphere-2025-80, https://doi.org/10.5194/egusphere-2025-80, 2025
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Plumes of wildfire smoke in the Arctic affect the Arctic radiative budget. Using a neural network and observations from satellite-based sensors, we analyzed the direct radiative forcing of smoke particles on the Arctic climate and estimated long-term forcing trends. Strong negative trends in aerosol direct radiative forcing were found in northern Russia and Canada, with positive trends found over parts of the Arctic Ocean. Overall, smoke plumes may act to counter future Arctic warming.
Fengjiao Chen, Yuanjian Yang, Lu Yu, Yang Li, Weiguang Liu, Yan Liu, and Simone Lolli
Atmos. Chem. Phys., 25, 1587–1601, https://doi.org/10.5194/acp-25-1587-2025, https://doi.org/10.5194/acp-25-1587-2025, 2025
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The microphysical mechanisms of precipitation responsible for the varied impacts of aerosol particles on shallow precipitation remain unclear. This study reveals that coarse aerosol particles invigorate shallow rainfall through enhanced coalescence processes, whereas fine aerosol particles suppress shallow rainfall through intensified microphysical breaks. These impacts are independent of thermodynamic environments but are more significant in low-humidity conditions.
Sohee Joo, Juseon Shin, Matthias Tesche, Naghmeh Dehkhoda, Taegyeong Kim, and Youngmin Noh
Atmos. Chem. Phys., 25, 1023–1036, https://doi.org/10.5194/acp-25-1023-2025, https://doi.org/10.5194/acp-25-1023-2025, 2025
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In our study, we investigated why, in northeast Asia, visibility has not improved even though air pollution levels have decreased. By examining trends in Seoul and Ulsan, we found that the particles in the air are getting smaller, which scatters light more effectively and reduces how far we can see. Our findings suggest that changes in particle properties adversely affected public perception of air quality improvement even though the PM2.5 mass concentration is continuously decreasing.
Abdulamid A. Fakoya, Jens Redemann, Pablo E. Saide, Lan Gao, Logan T. Mitchell, Calvin Howes, Amie Dobracki, Ian Chang, Gonzalo A. Ferrada, Kristina Pistone, Samuel E. Leblanc, Michal Segal-Rozenhaimer, Arthur J. Sedlacek III, Thomas Eck, Brent Holben, Pawan Gupta, Elena Lind, Paquita Zuidema, Gregory Carmichael, and Connor J. Flynn
EGUsphere, https://doi.org/10.5194/egusphere-2024-3197, https://doi.org/10.5194/egusphere-2024-3197, 2025
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Tiny atmospheric particles from wildfire smoke impact climate by interacting with sunlight and clouds, the extent of which is uncertain due to gaps in understanding how smoke changes over time. We developed a new method using remote sensing instruments to track how these particles evolve during atmospheric transport. Our results show that the ability of these particles to absorb sunlight increased as they travel. This discovery could help improve predictions of future climate scenarios.
Norman T. O'Neill, Keyvan Ranjbar, Liviu Ivănescu, Yann Blanchard, Seyed Ali Sayedain, and Yasmin AboEl-Fetouh
Atmos. Chem. Phys., 25, 27–44, https://doi.org/10.5194/acp-25-27-2025, https://doi.org/10.5194/acp-25-27-2025, 2025
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Dust from mid-latitude deserts or from local drainage basins is a weak component of atmospheric aerosols in the Arctic. Satellite-based dust estimates are often overestimated because dust and cloud measurements can be confused. Illustrations are given with an emphasis on the flawed claim that a classic indicator of dust (negative brightness temperature differences) is proof of the presence of airborne Arctic dust. Low-altitude warm-water plumes are the likely source of such negative values.
Saleem Ali, Chandan Sarangi, and Sanjay Kumar Mehta
EGUsphere, https://doi.org/10.5194/egusphere-2024-3093, https://doi.org/10.5194/egusphere-2024-3093, 2024
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The pollutants over Northern India are transported towards South India under the influence of the prevalent wind system, especially during winter. This long-range transport induces a widespread haziness over southern India, lasting for days. We evaluated the occurrence of such transport episodes over south India using observational methods and found that it suppresses the boundary layer height by ~38 % compared to the clear days while exacerbating the surface pollution by ~30–35 %.
Sofía Gómez Maqueo Anaya, Dietrich Althausen, Julian Hofer, Moritz Haarig, Ulla Wandinger, Bernd Heinold, Ina Tegen, Matthias Faust, Holger Baars, Albert Ansmann, Ronny Engelmann, Annett Skupin, Birgit Heese, and Kerstin Schepanski
EGUsphere, https://doi.org/10.5194/egusphere-2024-3159, https://doi.org/10.5194/egusphere-2024-3159, 2024
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This study investigates how hematite (an iron oxide mineral) in the Saharan Desert dust affects how dust particles interact with radiation. Using lidar data from Cabo Verde (2021–2022) and hematite content from atmospheric model simulations, the results show that higher hematite fraction leads to stronger particle backscattering at specific wavelengths. These findings can improve the representaiton of mineral dust in climate models, particularly regarding their radiative effect.
Perla Alalam, Fabrice Ducos, and Hervé Herbin
Atmos. Chem. Phys., 24, 12277–12294, https://doi.org/10.5194/acp-24-12277-2024, https://doi.org/10.5194/acp-24-12277-2024, 2024
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This study dives into the impact of mineral dust laboratory complex refractive indices (CRIs) on quantifying the dust microphysical properties using satellite infrared remote sensing. Results show that using CRIs obtained by advanced realistic techniques can improve the accuracy of these measurements, emphasizing the importance of choosing the suitable CRI in atmospheric models. This improvement is crucial for better predicting the dust radiative effect and impact on the climate.
Nabia Gulistan, Khan Alam, and Yangang Liu
Atmos. Chem. Phys., 24, 11333–11349, https://doi.org/10.5194/acp-24-11333-2024, https://doi.org/10.5194/acp-24-11333-2024, 2024
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This study looks at the influence of aerosol and meteorology on precipitating and non-precipitating clouds over the Indo-Gangetic Plain (IGP). A major finding of this study was that the high loading of aerosols led to a high occurrence of precipitating clouds under unstable conditions in summer. The study has the potential to open a new avenue for the scientific community to further explore and understand the complications of aerosol–cloud–precipitation over the complex topography of the IGP.
Myungje Choi, Alexei Lyapustin, Gregory L. Schuster, Sujung Go, Yujie Wang, Sergey Korkin, Ralph Kahn, Jeffrey S. Reid, Edward J. Hyer, Thomas F. Eck, Mian Chin, David J. Diner, Olga Kalashnikova, Oleg Dubovik, Jhoon Kim, and Hans Moosmüller
Atmos. Chem. Phys., 24, 10543–10565, https://doi.org/10.5194/acp-24-10543-2024, https://doi.org/10.5194/acp-24-10543-2024, 2024
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This paper introduces a retrieval algorithm to estimate two key absorbing components in smoke (black carbon and brown carbon) using DSCOVR EPIC measurements. Our analysis reveals distinct smoke properties, including spectral absorption, layer height, and black carbon and brown carbon, over North America and central Africa. The retrieved smoke properties offer valuable observational constraints for modeling radiative forcing and informing health-related studies.
Brian Harr, Bing Pu, and Qinjian Jin
Atmos. Chem. Phys., 24, 8625–8651, https://doi.org/10.5194/acp-24-8625-2024, https://doi.org/10.5194/acp-24-8625-2024, 2024
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We found that the formation of the extreme trans-Atlantic African dust event in June 2015 was associated with a brief surge in dust emissions over western North Africa and extreme circulation patterns, including intensified easterly jets, which facilitated the westward transport of dust. The dust plume modified radiative flux along its transport pathway but had minor impacts on air quality in the US due to the record-high Caribbean low-level jet advecting part of the plume to the Pacific.
James L. Gomez, Robert J. Allen, and King-Fai Li
Atmos. Chem. Phys., 24, 6937–6963, https://doi.org/10.5194/acp-24-6937-2024, https://doi.org/10.5194/acp-24-6937-2024, 2024
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Wildfires in California (CA) have grown very large during the past 20 years. These fires emit sunlight-absorbing aerosols. Analyzing observational data, our study finds that aerosols emitted from large fires in northern CA spread throughout CA and Nevada and heat the atmosphere. This heating is consistent with larger-than-normal temperatures and dry conditions. Further study is needed to determine how much the aerosols heat the atmosphere and whether they are drying the atmosphere as well.
Yuxuan Xing, Yang Chen, Shirui Yan, Xiaoyi Cao, Yong Zhou, Xueying Zhang, Tenglong Shi, Xiaoying Niu, Dongyou Wu, Jiecan Cui, Yue Zhou, Xin Wang, and Wei Pu
Atmos. Chem. Phys., 24, 5199–5219, https://doi.org/10.5194/acp-24-5199-2024, https://doi.org/10.5194/acp-24-5199-2024, 2024
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This study investigated the impact of dust storms from the Taklamakan Desert on surrounding high mountains and regional radiation balance. Using satellite data and simulations, researchers found that dust storms significantly darken the snow surface in the Tien Shan, Kunlun, and Qilian mountains, reaching mountains up to 1000 km away. This darkening occurs not only in spring but also during summer and autumn, leading to increased absorption of solar radiation.
Yuqin Liu, Tao Lin, Jiahua Zhang, Fu Wang, Yiyi Huang, Xian Wu, Hong Ye, Guoqin Zhang, Xin Cao, and Gerrit de Leeuw
Atmos. Chem. Phys., 24, 4651–4673, https://doi.org/10.5194/acp-24-4651-2024, https://doi.org/10.5194/acp-24-4651-2024, 2024
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A new method, the geographical detector method (GDM), has been applied to satellite data, in addition to commonly used statistical methods, to study the sensitivity of cloud properties to aerosol over China. Different constraints for aerosol and cloud liquid water path apply over polluted and clean areas. The GDM shows that cloud parameters are more sensitive to combinations of parameters than to individual parameters, but confounding effects due to co-variation of parameters cannot be excluded.
Kangwen Sun, Guangyao Dai, Songhua Wu, Oliver Reitebuch, Holger Baars, Jiqiao Liu, and Suping Zhang
Atmos. Chem. Phys., 24, 4389–4409, https://doi.org/10.5194/acp-24-4389-2024, https://doi.org/10.5194/acp-24-4389-2024, 2024
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This paper investigates the correlation between marine aerosol optical properties and wind speeds over remote oceans using the spaceborne lidars ALADIN and CALIOP. Three remote ocean areas are selected. Pure marine aerosol optical properties at 355 nm are derived from ALADIN. The relationships between marine aerosol optical properties and wind speeds are analyzed within and above the marine atmospheric boundary layer, revealing the effect of wind speed on marine aerosols over remote oceans.
Jingting Huang, S. Marcela Loría-Salazar, Min Deng, Jaehwa Lee, and Heather A. Holmes
Atmos. Chem. Phys., 24, 3673–3698, https://doi.org/10.5194/acp-24-3673-2024, https://doi.org/10.5194/acp-24-3673-2024, 2024
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Increased wildfire intensity has resulted in taller wildfire smoke plumes. We investigate the vertical structure of wildfire smoke plumes using aircraft lidar data and establish two effective smoke plume height metrics. Four novel satellite-based plume height products are evaluated for wildfires in the western US. Our results provide guidance on the strengths and limitations of these satellite products and set the stage for improved plume rise estimates by leveraging satellite products.
Piyushkumar N. Patel, Jonathan H. Jiang, Ritesh Gautam, Harish Gadhavi, Olga Kalashnikova, Michael J. Garay, Lan Gao, Feng Xu, and Ali Omar
Atmos. Chem. Phys., 24, 2861–2883, https://doi.org/10.5194/acp-24-2861-2024, https://doi.org/10.5194/acp-24-2861-2024, 2024
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Global measurements of cloud condensation nuclei (CCN) are essential for understanding aerosol–cloud interactions and predicting climate change. To address this gap, we introduced a remote sensing algorithm that retrieves vertically resolved CCN number concentrations from airborne and spaceborne lidar systems. This innovation offers a global distribution of CCN concentrations from space, facilitating model evaluation and precise quantification of aerosol climate forcing.
Lorraine A. Remer, Robert C. Levy, and J. Vanderlei Martins
Atmos. Chem. Phys., 24, 2113–2127, https://doi.org/10.5194/acp-24-2113-2024, https://doi.org/10.5194/acp-24-2113-2024, 2024
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Aerosols are small liquid or solid particles suspended in the atmosphere, including smoke, particulate pollution, dust, and sea salt. Today, we rely on satellites viewing Earth's atmosphere to learn about these particles. Here, we speculate on the future to imagine how satellite viewing of aerosols will change. We expect more public and private satellites with greater capabilities, better ways to infer information from satellites, and merging of data with models.
Xiaoxia Shang, Antti Lipponen, Maria Filioglou, Anu-Maija Sundström, Mark Parrington, Virginie Buchard, Anton S. Darmenov, Ellsworth J. Welton, Eleni Marinou, Vassilis Amiridis, Michael Sicard, Alejandro Rodríguez-Gómez, Mika Komppula, and Tero Mielonen
Atmos. Chem. Phys., 24, 1329–1344, https://doi.org/10.5194/acp-24-1329-2024, https://doi.org/10.5194/acp-24-1329-2024, 2024
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In June 2019, smoke particles from a Canadian wildfire event were transported to Europe. The long-range-transported smoke plumes were monitored with a spaceborne lidar and reanalysis models. Based on the aerosol mass concentrations estimated from the observations, the reanalysis models had difficulties in reproducing the amount and location of the smoke aerosols during the transport event. Consequently, more spaceborne lidar missions are needed for reliable monitoring of aerosol plumes.
Blake T. Sorenson, Jeffrey S. Reid, Jianglong Zhang, Robert E. Holz, William L. Smith Sr., and Amanda Gumber
Atmos. Chem. Phys., 24, 1231–1248, https://doi.org/10.5194/acp-24-1231-2024, https://doi.org/10.5194/acp-24-1231-2024, 2024
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Smoke particles are typically submicron in size and assumed to have negligible impacts at the thermal infrared spectrum. However, we show that infrared signatures can be observed over dense smoke plumes from satellites. We found that giant particles are unlikely to be the dominant cause. Rather, co-transported water vapor injected to the middle to upper troposphere and surface cooling beneath the plume due to shadowing are significant, with the surface cooling effect being the most dominant.
Farnaz Hosseinpour and Eric M. Wilcox
Atmos. Chem. Phys., 24, 707–724, https://doi.org/10.5194/acp-24-707-2024, https://doi.org/10.5194/acp-24-707-2024, 2024
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This study shows mechanistic relationships between the radiative effect of dust aerosols in the Saharan air layer and the kinetic energy of the African easterly waves across the tropical Atlantic Ocean using 22 years of daily satellite observations and reanalysis data based on satellite assimilation. Our findings suggest that dust aerosols not merely are transported by these waves but also contribute to the growth of waves through the enhancement of diabatic heating induced by dust.
Markus D. Petters, Tyas Pujiastuti, Ajmal Rasheeda Satheesh, Sabin Kasparoglu, Bethany Sutherland, and Nicholas Meskhidze
Atmos. Chem. Phys., 24, 745–762, https://doi.org/10.5194/acp-24-745-2024, https://doi.org/10.5194/acp-24-745-2024, 2024
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This work introduces a new method that uses remote sensing techniques to obtain surface number emissions of particles with a diameter greater than 500 nm. The technique was applied to study particle emissions at an urban site near Houston, TX, USA. The emissions followed a diurnal pattern and peaked near noon local time. The daily averaged emissions correlated with wind speed. The source is likely due to wind-driven erosion of material situated on asphalted and other hard surfaces.
Zhuang Wang, Chune Shi, Hao Zhang, Yujia Chen, Xiyuan Chi, Congzi Xia, Suyao Wang, Yizhi Zhu, Kaidi Zhang, Xintong Chen, Chengzhi Xing, and Cheng Liu
Atmos. Chem. Phys., 23, 14271–14292, https://doi.org/10.5194/acp-23-14271-2023, https://doi.org/10.5194/acp-23-14271-2023, 2023
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The annual cycle of dust and anthropogenic aerosols' vertical distributions was revealed by polarization Raman lidar in Beijing. Anthropogenic aerosols typically accumulate at the top of the mixing layer (ML) due to the hygroscopic growth of atmospheric particles, and this is most significant in summer. There is no significant relationship between bottom dust mass concentration and ML height, while the dust in the upper air tends to be distributed near the mixing layer.
Simone Lolli, Michaël Sicard, Francesco Amato, Adolfo Comeron, Cristina Gíl-Diaz, Tony C. Landi, Constantino Munoz-Porcar, Daniel Oliveira, Federico Dios Otin, Francesc Rocadenbosch, Alejandro Rodriguez-Gomez, Andrés Alastuey, Xavier Querol, and Cristina Reche
Atmos. Chem. Phys., 23, 12887–12906, https://doi.org/10.5194/acp-23-12887-2023, https://doi.org/10.5194/acp-23-12887-2023, 2023
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We evaluated the long-term trends and seasonal variability of the vertically resolved aerosol properties over the past 17 years in Barcelona. Results shows that air quality is improved, with a consistent drop in PM concentrations at the surface, as well as the column aerosol optical depth. The results also show that natural dust outbreaks are more likely in summer, with aerosols reaching an altitude of 5 km, while in winter, aerosols decay as an exponential with a scale height of 600 m.
Ludovico Di Antonio, Claudia Di Biagio, Gilles Foret, Paola Formenti, Guillaume Siour, Jean-François Doussin, and Matthias Beekmann
Atmos. Chem. Phys., 23, 12455–12475, https://doi.org/10.5194/acp-23-12455-2023, https://doi.org/10.5194/acp-23-12455-2023, 2023
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Long-term (2000–2021) 1 km resolution satellite data have been used to investigate the climatological aerosol optical depth (AOD) variability and trends at different scales in Europe. Average enhancements of the local-to-regional AOD ratio at 550 nm of 57 %, 55 %, 39 % and 32 % are found for large metropolitan areas such as Barcelona, Lisbon, Paris and Athens, respectively, suggesting a non-negligible enhancement of the aerosol burden through local emissions.
Sebastien Garrigues, Melanie Ades, Samuel Remy, Johannes Flemming, Zak Kipling, Istvan Laszlo, Mark Parrington, Antje Inness, Roberto Ribas, Luke Jones, Richard Engelen, and Vincent-Henri Peuch
Atmos. Chem. Phys., 23, 10473–10487, https://doi.org/10.5194/acp-23-10473-2023, https://doi.org/10.5194/acp-23-10473-2023, 2023
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The Copernicus Atmosphere Monitoring Service (CAMS) provides global monitoring of aerosols using the ECMWF forecast model constrained by the assimilation of satellite aerosol optical depth (AOD). This work aims at evaluating the assimilation of the NOAA VIIRS AOD product in the ECMWF model. It shows that the introduction of VIIRS in the CAMS data assimilation system enhances the accuracy of the aerosol analysis, particularly over Europe and desert and maritime sites.
Maria Filioglou, Ari Leskinen, Ville Vakkari, Ewan O'Connor, Minttu Tuononen, Pekko Tuominen, Samuli Laukkanen, Linnea Toiviainen, Annika Saarto, Xiaoxia Shang, Petri Tiitta, and Mika Komppula
Atmos. Chem. Phys., 23, 9009–9021, https://doi.org/10.5194/acp-23-9009-2023, https://doi.org/10.5194/acp-23-9009-2023, 2023
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Pollen impacts climate and public health, and it can be detected in the atmosphere by lidars which measure the linear particle depolarization ratio (PDR), a shape-relevant optical parameter. As aerosols also cause depolarization, surface aerosol and pollen observations were combined with measurements from ground-based lidars operating at different wavelengths to determine the optical properties of birch and pine pollen and quantify their relative contribution to the PDR.
Jesús Abril-Gago, Pablo Ortiz-Amezcua, Diego Bermejo-Pantaleón, Juana Andújar-Maqueda, Juan Antonio Bravo-Aranda, María José Granados-Muñoz, Francisco Navas-Guzmán, Lucas Alados-Arboledas, Inmaculada Foyo-Moreno, and Juan Luis Guerrero-Rascado
Atmos. Chem. Phys., 23, 8453–8471, https://doi.org/10.5194/acp-23-8453-2023, https://doi.org/10.5194/acp-23-8453-2023, 2023
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Validation activities of Aeolus wind products were performed in Granada with different upward-probing instrumentation (Doppler lidar system and radiosondes) and spatiotemporal collocation criteria. Specific advantages and disadvantages of each instrument were identified, and an optimal comparison criterion is proposed. Aeolus was proven to provide reliable wind products, and the upward-probing instruments were proven to be useful for Aeolus wind product validation activities.
Jianyu Zheng, Zhibo Zhang, Hongbin Yu, Anne Garnier, Qianqian Song, Chenxi Wang, Claudia Di Biagio, Jasper F. Kok, Yevgeny Derimian, and Claire Ryder
Atmos. Chem. Phys., 23, 8271–8304, https://doi.org/10.5194/acp-23-8271-2023, https://doi.org/10.5194/acp-23-8271-2023, 2023
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We developed a multi-year satellite-based retrieval of dust optical depth at 10 µm and the coarse-mode dust effective diameter over global oceans. It reveals climatological coarse-mode dust transport patterns and regional differences over the North Atlantic, the Indian Ocean and the North Pacific.
Shikuan Jin, Yingying Ma, Zhongwei Huang, Jianping Huang, Wei Gong, Boming Liu, Weiyan Wang, Ruonan Fan, and Hui Li
Atmos. Chem. Phys., 23, 8187–8210, https://doi.org/10.5194/acp-23-8187-2023, https://doi.org/10.5194/acp-23-8187-2023, 2023
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To better understand the Asian aerosol environment, we studied distributions and trends of aerosol with different sizes and types. Over the past 2 decades, dust, sulfate, and sea salt aerosol decreased by 5.51 %, 3.07 %, and 9.80 %, whereas organic carbon and black carbon aerosol increased by 17.09 % and 6.23 %, respectively. The increase in carbonaceous aerosols was a feature of Asia. An exception is found in East Asia, where the carbonaceous aerosols reduced, owing largely to China's efforts.
Mukunda M. Gogoi, S. Suresh Babu, Ryoichi Imasu, and Makiko Hashimoto
Atmos. Chem. Phys., 23, 8059–8079, https://doi.org/10.5194/acp-23-8059-2023, https://doi.org/10.5194/acp-23-8059-2023, 2023
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Considering the climate warming potential of atmospheric black carbon (BC), satellite-based retrieval is a novel idea. This study highlights the regional distribution of BC based on observations by the Cloud and Aerosol Imager-2 on board the GOSAT-2 satellite and near-surface measurements of BC in ARFINET. The satellite retrieval fairly depicts the regional and seasonal features of BC over the Indian region, which are similar to those recorded by surface observations.
Hao Fan, Xingchuan Yang, Chuanfeng Zhao, Yikun Yang, and Zhenyao Shen
Atmos. Chem. Phys., 23, 7781–7798, https://doi.org/10.5194/acp-23-7781-2023, https://doi.org/10.5194/acp-23-7781-2023, 2023
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Using 20-year multi-source data, this study shows pronounced regional and seasonal variations in fire activities and emissions. Seasonal variability of fires is larger with increasing latitude. The increase in temperature in the Northern Hemisphere's middle- and high-latitude forest regions was primarily responsible for the increase in fires and emissions, while the changes in fire occurrence in tropical regions were more influenced by the decrease in precipitation and relative humidity.
Rosemary Huck, Robert G. Bryant, and James King
Atmos. Chem. Phys., 23, 6299–6318, https://doi.org/10.5194/acp-23-6299-2023, https://doi.org/10.5194/acp-23-6299-2023, 2023
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This study shows that mineral aerosol (dust) emission events in high-latitude areas are under-represented in both ground- and space-based detecting methods. This is done through a suite of ground-based data to prove that dust emissions from the proglacial area, Lhù’ààn Mân, occur almost daily but are not always recorded at different timescales. Dust has multiple effects on atmospheric processes; therefore, accurate quantification is important in the calibration and validation of climate models.
Michail Mytilinaios, Sara Basart, Sergio Ciamprone, Juan Cuesta, Claudio Dema, Enza Di Tomaso, Paola Formenti, Antonis Gkikas, Oriol Jorba, Ralph Kahn, Carlos Pérez García-Pando, Serena Trippetta, and Lucia Mona
Atmos. Chem. Phys., 23, 5487–5516, https://doi.org/10.5194/acp-23-5487-2023, https://doi.org/10.5194/acp-23-5487-2023, 2023
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Multiscale Online Non-hydrostatic AtmospheRe CHemistry model (MONARCH) dust reanalysis provides a high-resolution 3D reconstruction of past dust conditions, allowing better quantification of climate and socioeconomic dust impacts. We assess the performance of the reanalysis needed to reproduce dust optical depth using dust-related products retrieved from satellite and ground-based observations and show that it reproduces the spatial distribution and seasonal variability of atmospheric dust well.
Jacob Z. Tindan, Qinjian Jin, and Bing Pu
Atmos. Chem. Phys., 23, 5435–5466, https://doi.org/10.5194/acp-23-5435-2023, https://doi.org/10.5194/acp-23-5435-2023, 2023
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We use the Infrared Atmospheric Sounder Interferometer (IASI) retrievals of dust variables (dust optical depth and dust layer height) and surface observations to understand the day- and nighttime variations in dust aerosols over the dust belt. Our results show that daytime dust aerosols are significantly different from nighttime, and such day–night variations are influenced by meteorological factors such as wind speed, precipitation, and turbulent motions within the atmospheric boundary layer.
Ross Herbert and Philip Stier
Atmos. Chem. Phys., 23, 4595–4616, https://doi.org/10.5194/acp-23-4595-2023, https://doi.org/10.5194/acp-23-4595-2023, 2023
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We provide robust evidence from multiple sources showing that smoke from fires in the Amazon rainforest significantly modifies the diurnal cycle of convection and cools the climate. Low to moderate amounts of smoke increase deep convective clouds and rain, whilst beyond a threshold amount, the smoke starts to suppress the convection and rain. We are currently at this threshold, suggesting increases in fires from agricultural practices or droughts will reduce cloudiness and rain over the region.
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Short summary
Data about the Earth are routinely obtained from satellite observations, model simulations, and ground-based or other measurements. These are at different space and timescales, and it is common to average them to reduce gaps and increase ease of use. The question of how the data should be averaged depends on the underlying distribution of the quantity. This study presents a method for determining how to appropriately aggregate data and applies it to data sets about atmospheric aerosol levels.
Data about the Earth are routinely obtained from satellite observations, model simulations, and...
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