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- Warm and moist air intrusions into the winter Arctic: a Lagrangian view on
the near-surface energy budgets Abstract: Warm and moist air intrusions into the winter Arctic: a Lagrangian view on the near-surface energy budgets Cheng You, Michael Tjernström, and Abhay Devasthale Atmos. Chem. Phys., 22, 8037–8057, https://doi.org/10.5194/acp-22-8037-2022, 2022 In winter when solar radiation is absent in the Arctic, the poleward transport of heat and moisture into the high Arctic becomes the main contribution of Arctic warming. Over completely frozen ocean sectors, total surface energy budget is dominated by net long-wave heat, while over the Barents Sea, with an open ocean to the south, total net surface energy budget is dominated by the surface turbulent heat. PubDate: Tue, 21 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-22-8037-2022 2022
- The formation and composition of the Mount Everest plume in winter
Abstract: The formation and composition of the Mount Everest plume in winter Edward E. Hindman and Scott Lindstrom Atmos. Chem. Phys., 22, 7995–8008, https://doi.org/10.5194/acp-22-7995-2022, 2022 Winds buffeting the Mt. Everest massif often produce plumes. This systematic study identified plumes from daily observations of real-time, on-line images from a geosynchronous meteorological satellite. The corresponding meteorological data were used with a cloud-forming model to show the plumes were composed, depending on the temperature, of droplets, crystals or both. They were not composed of resuspended snow, which is a common belief. We estimated the plumes may produce significant snowfall. PubDate: Tue, 21 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-22-7995-2022 2022
- Characteristics and evolution of brown carbon in western United States
wildfires Abstract: Characteristics and evolution of brown carbon in western United States wildfires Linghan Zeng, Jack Dibb, Eric Scheuer, Joseph M. Katich, Joshua P. Schwarz, Ilann Bourgeois, Jeff Peischl, Tom Ryerson, Carsten Warneke, Anne E. Perring, Glenn S. Diskin, Joshua P. DiGangi, John B. Nowak, Richard H. Moore, Elizabeth B. Wiggins, Demetrios Pagonis, Hongyu Guo, Pedro Campuzano-Jost, Jose L. Jimenez, Lu Xu, and Rodney J. Weber Atmos. Chem. Phys., 22, 8009–8036, https://doi.org/10.5194/acp-22-8009-2022, 2022 Wildfires emit aerosol particles containing brown carbon material that affects visibility and global climate and is toxic. Brown carbon is poorly characterized due to measurement limitations, and its evolution in the atmosphere is not well known. We report on aircraft measurements of brown carbon from large wildfires in the western United States. We compare two methods for measuring brown carbon and study the evolution of brown carbon in the smoke as it moved away from the burning regions. PubDate: Tue, 21 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-22-8009-2022 2022
- Using Aircraft Measurements to Characterize Subgrid-Scale Variability of
Aerosol Properties Near the ARM Southern Great Plains Site Abstract: Using Aircraft Measurements to Characterize Subgrid-Scale Variability of Aerosol Properties Near the ARM Southern Great Plains Site Jerome D. Fast, David Bell, Jiumeng Liu, Fan Mei, Georges Saliba, John E. Shilling, Kaitlyn Suski, Jason Tomlinson, Jian Wang, Rahul Zaveri, and Alla Zelenyuk Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-384,2022 Preprint under review for ACP (discussion: open, 0 comments) Recent aircraft measurements from the HI-SCALE campaign conducted over the Southern Great Plains (SGP) site in Oklahoma are used to quantify spatial variability of aerosol properties in terms of grid spacings typically used by weather and climate models. Surprisingly large horizontal gradients in aerosol properties were frequently observed in this rural area. This spatial variability can be used as an uncertainty range when comparing surface point measurements to model predictions. PubDate: Tue, 21 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-2022-3842022
- Fluorescence characteristics, absorption properties, and radiative effects
of water-soluble organic carbon in seasonal snow across northeastern China Abstract: Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China Xiaoying Niu, Wei Pu, Pingqing Fu, Yang Chen, Yuxuan Xing, Dongyou Wu, Ziqi Chen, Tenglong Shi, Yue Zhou, Hui Wen, and Xin Wang Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-336,2022 Preprint under review for ACP (discussion: open, 0 comments) In this study, we made the first investigation of WSOC in seasonal snow of northeastern China. The results revealed the regional-specific compositions and sources of WSOC due to different anthropogenic activities and natural environments. The abundant concentrations of WSOC and its absorption properties contributed to the crucial impact on the snow albedo and radiative effect. We implied that our study could raise awareness of carbon cycling processes, hydrological processes, and climate change. PubDate: Tue, 21 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-2022-3362022
- Limitations in representation of physical processes prevent successful
simulation of PM2.5 during KORUS-AQ Abstract: Limitations in representation of physical processes prevent successful simulation of PM2.5 during KORUS-AQ Katherine R. Travis, James H. Crawford, Gao Chen, Carolyn E. Jordan, Benjamin A. Nault, Hwajin Kim, Jose L. Jimenez, Pedro Campuzano-Jost, Jack E. Dibb, Jung-Hun Woo, Younha Kim, Shixian Zhai, Xuan Wang, Erin E. McDuffie, Gan Luo, Fangqun Yu, Saewung Kim, Isobel J. Simpson, Donald R. Blake, Limseok Chang, and Michelle J. Kim Atmos. Chem. Phys., 22, 7933–7958, https://doi.org/10.5194/acp-22-7933-2022, 2022 The 2016 Korea–United States Air Quality (KORUS-AQ) field campaign provided a unique set of observations to improve our understanding of PM2.5 pollution in South Korea. Models typically have errors in simulating PM2.5 in this region, which is of concern for the development of control measures. We use KORUS-AQ observations to improve our understanding of the mechanisms driving PM2.5 and the implications of model errors for determining PM2.5 that is attributable to local or foreign sources. PubDate: Mon, 20 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-22-7933-2022 2022
- Dust transport and advection measurement with spaceborne lidars ALADIN and
CALIOP and model reanalysis data Abstract: Dust transport and advection measurement with spaceborne lidars ALADIN and CALIOP and model reanalysis data Guangyao Dai, Kangwen Sun, Xiaoye Wang, Songhua Wu, Xiangying E, Qi Liu, and Bingyi Liu Atmos. Chem. Phys., 22, 7975–7993, https://doi.org/10.5194/acp-22-7975-2022, 2022 In this paper, a Sahara dust event is tracked with the spaceborne lidars ALADIN and CALIOP and the models ECMWF and HYSPLIT. The performance of ALADIN and CALIOP on tracking the dust event and on the observations of dust optical properties and wind fields during the dust transport is evaluated. The dust mass advection is defined, which is calculated with the combination of data from ALADIN and CALIOP coupled with the products from models to describe the dust transport quantitatively. PubDate: Mon, 20 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-22-7975-2022 2022
- Continental thunderstorm ground enhancement observed at an exceptionally
low altitude Abstract: Continental thunderstorm ground enhancement observed at an exceptionally low altitude Ivana Kolmašová, Ondřej Santolík, Jakub Šlegl, Jana Popová, Zbyněk Sokol, Petr Zacharov, Ondřej Ploc, Gerhard Diendorfer, Ronald Langer, Radek Lán, and Igor Strhárský Atmos. Chem. Phys., 22, 7959–7973, https://doi.org/10.5194/acp-22-7959-2022, 2022 Gamma ray radiation related to thunderstorms was previously observed at the high-altitude mountain observatories or on the western coast of Japan, usually being terminated by lightning discharges. We show unusual observations of gamma rays at an altitude below 1000 m, coinciding with peculiar rapid variations in the vertical electric field, which are linked to inverted intracloud lightning discharges. This indicates that a strong, lower positive-charge region was present inside the thundercloud. PubDate: Mon, 20 Jun 2022 06:07:18 +020 DOI: 10.5194/acp-22-7959-2022 2022
- The Sun's role in decadal climate predictability in the North Atlantic
Abstract: The Sun's role in decadal climate predictability in the North Atlantic Annika Drews, Wenjuan Huo, Katja Matthes, Kunihiko Kodera, and Tim Kruschke Atmos. Chem. Phys., 22, 7893–7904, https://doi.org/10.5194/acp-22-7893-2022, 2022 Solar irradiance varies with a period of approximately 11 years. Using a unique large chemistry–climate model dataset, we investigate the solar surface signal in the North Atlantic and European region and find that it changes over time, depending on the strength of the solar cycle. For the first time, we estimate the potential predictability associated with including realistic solar forcing in a model. These results may improve seasonal to decadal predictions of European climate. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7893-2022 2022
- Net ecosystem exchange (NEE) estimates 2006–2019 over Europe from a
pre-operational ensemble-inversion system Abstract: Net ecosystem exchange (NEE) estimates 2006–2019 over Europe from a pre-operational ensemble-inversion system Saqr Munassar, Christian Rödenbeck, Frank-Thomas Koch, Kai U. Totsche, Michał Gałkowski, Sophia Walther, and Christoph Gerbig Atmos. Chem. Phys., 22, 7875–7892, https://doi.org/10.5194/acp-22-7875-2022, 2022 The results obtained from ensembles of inversions over 13 years show the largest spread in the a posteriori fluxes over the station set ensemble. Using different prior fluxes in the inversions led to a smaller impact. Drought occurrences in 2018 and 2019 affected CO2 fluxes as seen in net ecosystem exchange estimates. Our study highlights the importance of expanding the atmospheric site network across Europe to better constrain CO2 fluxes in inverse modelling. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7875-2022 2022
- Suppressed migrating diurnal tides in the mesosphere and lower
thermosphere region during El Niño in northern winter and its possible mechanism Abstract: Suppressed migrating diurnal tides in the mesosphere and lower thermosphere region during El Niño in northern winter and its possible mechanism Yetao Cen, Chengyun Yang, Tao Li, James M. Russell III, and Xiankang Dou Atmos. Chem. Phys., 22, 7861–7874, https://doi.org/10.5194/acp-22-7861-2022, 2022 The MLT DW1 amplitude is suppressed during El Niño winters in both satellite observation and SD-WACCM simulations. The suppressed Hough mode (1, 1) in the tropopause region propagates vertically to the MLT region, leading to decreased DW1 amplitude. The latitudinal zonal wind shear anomalies during El Niño winters would narrow the waveguide and prevent the vertical propagation of DW1. The gravity wave drag excited by ENSO-induced anomalous convection could also modulate the MLT DW1 amplitude. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7861-2022 2022
- Record-breaking dust loading during two mega dust storm events over
northern China in March 2021: aerosol optical and radiative properties and meteorological drivers Abstract: Record-breaking dust loading during two mega dust storm events over northern China in March 2021: aerosol optical and radiative properties and meteorological drivers Ke Gui, Wenrui Yao, Huizheng Che, Linchang An, Yu Zheng, Lei Li, Hujia Zhao, Lei Zhang, Junting Zhong, Yaqiang Wang, and Xiaoye Zhang Atmos. Chem. Phys., 22, 7905–7932, https://doi.org/10.5194/acp-22-7905-2022, 2022 This study investigates the aerosol optical and radiative properties and meteorological drivers during two mega SDS events over Northern China in March 2021. The MODIS-retrieved DOD data registered these two events as the most intense episode in the same period in history over the past 20 years. These two extreme SDS events were associated with both atmospheric circulation extremes and local meteorological anomalies that favor enhanced dust emissions in the Gobi Desert. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7905-2022 2022
- Reduced surface fine dust under droughts over the southeastern United
States during summertime: observations and CMIP6 model simulations Abstract: Reduced surface fine dust under droughts over the southeastern United States during summertime: observations and CMIP6 model simulations Wei Li and Yuxuan Wang Atmos. Chem. Phys., 22, 7843–7859, https://doi.org/10.5194/acp-22-7843-2022, 2022 Fine dust is an important component of PM2.5 and can be largely modulated by droughts. In contrast to the increase in dust in the southwest USA where major dust sources are located, dust in the southeast USA is affected more by long-range transport from Africa and decreases under droughts. Both the transport and emissions of African dust are weakened when the southeast USA is under droughts, which reveals how regional-scale droughts can influence aerosol abundance through long-range transport. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7843-2022 2022
- 14 years of lidar measurements of Polar Stratospheric Clouds at the French
Antarctic Station Dumont d'Urville Abstract: 14 years of lidar measurements of Polar Stratospheric Clouds at the French Antarctic Station Dumont d'Urville Florent Tencé, Julien Jumelet, Marie Bouillon, David Cugnet, Slimane Bekki, Sarah Safieddine, Philippe Keckhut, and Alain Sarkissian Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-401,2022 Preprint under review for ACP (discussion: open, 0 comments) Polar Stratospheric Clouds (PSC) are critical precursors to stratospheric ozone depletion, and measurement-driven classifications remain a key to accurate cloud modelling. We present PSC lidar observations conducted at the French Antarctic station Dumont d’Urville between 2007 and 2020. This dataset is analyzed using typical PSC classification schemes. We present a PSC climatology along with a significant and slightly negative 14-year trend of PSC occurences at around -5.7 PSC days per decade. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-2022-4012022
- Measurement report: Size distributions of urban aerosols down to 1 nm from
long-term measurements Abstract: Measurement report: Size distributions of urban aerosols down to 1 nm from long-term measurements Chenjuan Deng, Yiran Li, Chao Yan, Jin Wu, Runlong Cai, Dongbin Wang, Yongchun Liu, Juha Kangasluoma, Veli-Matti Kerminen, Markku Kulmala, and Jingkun Jiang Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-414,2022 Preprint under review for ACP (discussion: open, 0 comments) The size distributions of urban atmospheric particles convey important information on their origins and impacts. This study investigates the characteristics of typical particle size distributions together with key gaseous precursors from the long-term perspective in urban Beijing. A fitting function is proposed to represent and help to interpret the size distribution including particles and gaseous precursors. In addition to NPF as the major source, vehicles can emit sub-3 nm particles as well. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-2022-4142022
- Contributions of meteorology and anthropogenic emissions to the trends in
winter PM2.5 in eastern China 2013–2018 Abstract: Contributions of meteorology and anthropogenic emissions to the trends in winter PM2.5 in eastern China 2013–2018 Yanxing Wu, Run Liu, Yanzi Li, Junjie Dong, Zhijiong Huang, Junyu Zheng, and Shaw Chen Liu Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-304,2022 Preprint under review for ACP (discussion: open, 0 comments) Multiple linear regression (MLR) analyses often interpret the correlation coefficient (CC) as the contribution of an independent variable to the dependent variable. Since a good correlation does not imply a causal relationship, we propose that CC should be interpreted as the maximum possible contribution. Moreover, MLR results are sensitive to the length of time analyzed, long-term analysis gives a more accurate assessment because of its additional constraints. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-2022-3042022
- Methane emissions responsible for record-breaking atmospheric methane
growth rates in 2020 and 2021 Abstract: Methane emissions responsible for record-breaking atmospheric methane growth rates in 2020 and 2021 Liang Feng, Paul I. Palmer, Robert J. Parker, Mark F. Lunt, and Hartmut Boesch Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-425,2022 Preprint under review for ACP (discussion: open, 1 comment) Our understanding of recent changes in atmospheric methane has defied explanation. The atmospheric growth of methane has since 2007 accelerated to record-breaking values in 2020 and 2021. We use satellite observations of methane to show that 1) increasing emissions over the tropics are mostly responsible for these recent atmospheric changes, and 2) changes in the OH sink during the 2020 Covid-19 shutdown can explain up to 20 % of changes in atmospheric methane for that year. PubDate: Fri, 17 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-2022-4252022
- Discrepancy in assimilated atmospheric CO over East Asia in 2015–2020 by
assimilating satellite and surface CO measurements Abstract: Discrepancy in assimilated atmospheric CO over East Asia in 2015–2020 by assimilating satellite and surface CO measurements Zhaojun Tang, Jiaqi Chen, and Zhe Jiang Atmos. Chem. Phys., 22, 7815–7826, https://doi.org/10.5194/acp-22-7815-2022, 2022 We provide a comparative analysis to explore the effects of satellite and surface measurements on atmospheric CO in data assimilations in 2015–2020 over East Asia. We find possible overestimated enhancements of atmospheric CO by assimilating surface CO measurements due to model representation errors, and a large discrepancy in the derived trends of CO columns due to different vertical sensitivities of satellite and surface observations to lower and free troposphere. PubDate: Thu, 16 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7815-2022 2022
- Measurement report: Effects of anthropogenic emissions and environmental
factors on the formation of biogenic secondary organic aerosol (BSOA) in a coastal city of southeastern China Abstract: Measurement report: Effects of anthropogenic emissions and environmental factors on the formation of biogenic secondary organic aerosol (BSOA) in a coastal city of southeastern China Youwei Hong, Xinbei Xu, Dan Liao, Taotao Liu, Xiaoting Ji, Ke Xu, Chunyang Liao, Ting Wang, Chunshui Lin, and Jinsheng Chen Atmos. Chem. Phys., 22, 7827–7841, https://doi.org/10.5194/acp-22-7827-2022, 2022 Secondary organic aerosol (SOA) simulation remains uncertain, due to the unknown SOA formation mechanisms. Aerosol samples with a 4 h time resolution were collected, along with online measurements of aerosol chemical compositions and meteorological parameters. We found that anthropogenic emissions, atmospheric oxidation capacity and halogen chemistry have significant effects on the formation of biogenic SOA (BSOA). The findings of this study are helpful to better explore the missed SOA sources. PubDate: Thu, 16 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-22-7827-2022 2022
- Current and future prediction of inter-provincial transport of ambient
PM2.5 in China Abstract: Current and future prediction of inter-provincial transport of ambient PM2.5 in China Shansi Wang, Siwei Li, Jia Xing, Yu Ding, Senlin Hu, Shuchang Liu, Yu Qin, Zhaoxin Dong, Jiaxin Dong, Ge Song, and Lechao Dong Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2022-368,2022 Preprint under review for ACP (discussion: open, 0 comments) Future warming meteorological conditions may enhance the influence of regional transport on PM2.5 pollution. Our results prove that climate-friendly policy could lead to considerable co-benefits in mitigating the regional transport of PM2.5 in future. Meanwhile, climate change will exert larger impacts on across-regional (long-distance) transport than inner (neighboring provinces) regional transport, highlighting the significance of multi-regional cooperation in the future. PubDate: Thu, 16 Jun 2022 03:37:37 +020 DOI: 10.5194/acp-2022-3682022
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