The Representation of Sea Salt Aerosols and Their Role in Polar Climate Within CMIP6

Journal of Geophysical Research Atmospheres, Journal Year: 2023, Volume and Issue: 128(6)

Published: March 7, 2023

Abstract Natural aerosols and their interactions with clouds remain an important uncertainty within climate models, especially at the poles. Here, we study behavior of sea salt (SSaer) in Arctic Antarctic 12 models from CMIP6. We investigate driving factors that control SSaer abundances show large differences based on choice source function, representation aerosol processes atmosphere. Close to poles, CMIP6 do not match observed seasonal cycles surface concentrations, likely due absence wintertime sources such as blowing snow. Further away simulated concentrations have correct seasonality, but a positive mean bias up one order magnitude. optical depth is derived MODIS data compared modeled values, revealing good agreement, except for winter months. Better agreement than concentration may indicate need improving vertical distribution, size distribution and/or hygroscopicity polar SSaer. Source functions used emit very different numbers small SSaer, potentially exacerbating cloud‐aerosol interaction uncertainties these remote regions. For future scenarios SSP126 SSP585, increase both poles end 21st century, more two times mid‐20th century values Arctic. The pre‐industrial experiments suggest there radiative budget

Language: Английский

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Arctic spring and summertime aerosol optical depth baseline from long-term observations and model reanalyses – Part 2: Statistics of extreme AOD events, and implications for the impact of regional biomass burning processes

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(15), P. 9949 - 9967

Published: Aug. 3, 2022

Abstract. In a companion paper (Xian et al., 2022, part 1 of the study), we present an Arctic aerosol optical depth (AOD) climatology and trend analysis for 2003–2019 spring summertime periods derived from combination reanalyses, remote-sensing retrievals, ground observations. Continued previous discussion as second study, report statistics trends AOD extreme events using U.S. Navy Aerosol Analysis Prediction System ReAnalysis version (NAAPS-RA v1), sun photometer data AErosol RObotic NETwork (AERONET) sites, oceanic Maritime Network (MAN) measurements. Here, are defined with exceeding 95th percentile (denoted “AOD95”) distributions given locations 6-hourly or daily data. While AERONET MAN estimate median 550 nm value to be 0.07, is 0.24. Such dominated by fine-mode particles, largely attributable biomass burning (BB) smoke North American Arctic, Asian most areas Ocean. However, lower European more anthropogenic biogenic fine particles. The extreme-event occurrence dominance sea salt limited Atlantic Norwegian Sea. amplitudes are, however, significantly than those regions where dominant. Even sites distant BB source regions, principal driver variation above AOD95 threshold. Maximum values in high 2010–2019 have increased compared 2003–2009, indicating stronger influence recent years. tended equally distributed over all months (April–August) during 2003–2009 period while being concentrated late season (July–August) period. temporal shift likely due improved control early-season agriculture burning, climate-change-related increases lightning frequencies, reduction pollution

Language: Английский

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Assessment of the Spatial Structure of Black Carbon Concentrations in the Near-Surface Arctic Atmosphere

Atmosphere, Journal Year: 2023, Volume and Issue: 14(1), P. 139 - 139

Published: Jan. 8, 2023

The results of the research are numerical estimates average fields black carbon mass concentration in surface layer atmosphere Arctic region obtained using numeric technology referred to as fluid location (FLA). modelling has been based on measurements concentrations near-surface during two cruises Professor Multanovskiy (28 July–7 September 2019) and Akademik Mstislav Keldysh (31 July–24 August 2020) vessels. These have supplemented by at stationary monitoring points located Spitsbergen Severnaya Zemlya archipelagoes. simulation summertime demonstrates that areas increased were observed over Northern Europe and, 2019, also Laptev Sea basin. spatial distribution qualitatively agreed with same data derived from second Modern-Era Retrospective analysis for Research Applications (MERRA-2) but showed quantitative differences. values zones follows: 85.3 ng/m3 (2019) 53.6 (2020) reconstructed FLA technology; 261.69 131.8 MERRA-2 data.

Language: Английский

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Polar Aerosol Atmospheric Rivers: Detection, Characteristics, and Potential Applications

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(2)

Published: Jan. 13, 2024

Abstract Aerosols play a key role in polar climate, and are affected by long‐range transport from the mid‐latitudes, both Arctic Antarctic. This work investigates poleward extreme events of aerosols, referred to as aerosol atmospheric rivers (p‐AAR), leveraging concept (AR) which signal moisture. Using reanalysis data, we build detection catalog p‐AARs for black carbon, dust, sea salt organic carbon period 1980–2022. First, describe algorithm, discuss its sensitivity, evaluate validity. Then, present several case studies, Antarctic, illustrating complementarity between ARs p‐AARs. Despite similarities pathways during co‐occurring AR/p‐AAR events, vertical profiles differ depending on species, large‐scale patterns show that moisture aerosols do not necessarily originate same areas. The AR p‐AAR is also evidenced their long‐term characteristics terms spatial distribution, seasonality trends. detection, complement AR, can have important applications better understanding climate connections mid‐latitudes.

Language: Английский

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Intercomparison of aerosol optical depths from four reanalyses and their multi-reanalysis consensus

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(10), P. 6385 - 6411

Published: May 31, 2024

Abstract. The emergence of aerosol reanalyses in recent years has facilitated a comprehensive and systematic evaluation optical depth (AOD) trends attribution over multi-decadal timescales. Notable multi-year currently available include NAAPS-RA from the US Naval Research Laboratory, NASA MERRA-2, JRAero Japan Meteorological Agency (JMA), CAMSRA Copernicus/ECMWF. These are based on differing underlying meteorology models, representations processes, as well data assimilation methods treatment AOD observations. This study presents basic verification characteristics these four versus both AERONET MODIS retrievals monthly properties identifies strength each reanalysis regions where divergence challenges prominent. Regions with high pollution often mixed fine-mode coarse-mode environments, such South Asia, East Southeast Maritime Continent, pose significant challenges, indicated by higher root mean square error. Moreover, that distant major source areas, including polar remote oceans, exhibit large relative differences speciated AODs among reanalyses. To ensure consistency across globe, multi-reanalysis consensus (MRC, i.e., ensemble mean) approach was developed similarly to International Cooperative for Aerosol Prediction Multi-Model Ensemble (ICAP-MME). Like ICAP-MME, while MRC does not consistently rank first individual regions, it performs ranking or second globally correlation RMSE, making suitable candidate climate studies require robust consistent assessments.

Language: Английский

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A Coupled Evaluation of Operational MODIS and Model Aerosol Products for Maritime Environments Using Sun Photometry: Evaluation of the Fine and Coarse Mode

Remote Sensing, Journal Year: 2022, Volume and Issue: 14(13), P. 2978 - 2978

Published: June 22, 2022

Although satellite retrievals and data assimilation have progressed to where there is a good skill for monitoring maritime Aerosol Optical Depth (AOD), remains uncertainty in achieving further degrees of freedom, such as distinguishing fine coarse mode dominated species environments (e.g., sea salt dust versus terrestrial anthropogenic emissions, biomass burning, secondary production). For the years 2016 through 2019, we performed an analysis 550 nm total AOD550, AOD (FAOD550; also known FM literature), (CAOD550), fraction (η550) between Moderate Resolution Spectral Imaging Radiometer (MODIS) V6.1 MOD/MYD04 dark target aerosol International Cooperative Prediction (ICAP) core four multi-model consensus (C4C) analyses/short term forecasts that assimilate MODIS AOD550. Differences were adjudicated by global shipboard Maritime Network (MAN) selected island AERONET sun photometer observations with application spectral deconvolution algorithm (SDA). Through series conditional regional analyses, found divergence included regions influence latitudinal dependencies remote oceans. Notably, C4C its members, while having correlations overall, persistent +0.04 +0.02 biases relative MAN typical AOD550 values (84th% < 0.28), underestimating significant events thereafter. Second, high are largely associated attribution satellites models alike. Thus, both members systematically overestimating FAOD550 but perform better characterizing CAOD550. Third, MODIS, findings consistent previous reports bias retrieved Ångström Exponent, diagnosed optical model cloud masking likely causal factors bias, whereas C4C, it from overproduction perhaps numerical diffusion. Fourth, no wind-speed-dependent surface winds <12 m s−1, AOD550s overestimate CAOD550 FAOD550, respectively, wind speeds above 12 m/s. Finally, sampling inherent MAN, well other circumstantial evidence, suggests even larger than what was here. We conclude discussion on how products their own strengths challenges given climate discuss needed research.

Language: Английский

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Remote-sensing detectability of airborne Arctic dust

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(1), P. 27 - 44

Published: Jan. 6, 2025

Abstract. Remote-sensing (RS)-based estimates of Arctic dust are oftentimes overestimated due to a failure in separating out the contribution from that spatially homogeneous clouds or low-altitude cloud-like plumes. A variety illustrations given with particular emphasis on questionable claims using brightness temperature differences (BTDs) as signature indicator transported mid-latitude deserts generated by local sources. While there is little dispute about presence both Asian and across Arctic, direct RS detectability airborne dust, ascribed satellite (MODIS AVHRR) measurements significantly negative at 11 12 µm (BTD11–12), has been misrepresented certain cases. it difficult account for all examples strongly BTD11–12 values unlikely plays significant role. One much more likely contributor would be water inversion layer. The impact (notably sources) can, however, significance. Sustained deposition can substantially decrease (visible shortwave IR) snow ice reflectance albedo (pan-chromatic reflectance) signal measured sensors. Significantly would, only represent limited area near drainage basin sources according our event-level case studies. enhanced ice-nucleating particle (INP) role example, induce changes properties low-level mixed-phase (cloud optical depth <∼ 1) readily detected active passive instruments. It critical distinction between versus impacts understood if we appropriately parameterize, radiative forcing influence this climate-sensitive region.

Language: Английский

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Three-Dimensional Distribution of Arctic Aerosols Based on CALIOP Data

Remote Sensing, Journal Year: 2025, Volume and Issue: 17(5), P. 903 - 903

Published: March 4, 2025

Tropospheric aerosols play an important role in the notable warming phenomenon and climate change occurring Arctic. The accuracy of Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol optical depth (AOD) distribution Arctic AOD based on CALIOP Level 2 products Aerosol Robotic Network (AERONET) data during 2006–2021 were analyzed. distributions, trends, three-dimensional (3D) structures frequency occurrences (FoOs) different subtypes are also discussed. We found that exhibited a high level agreement AERONET AOD, correlation coefficient approximately 0.67 RMSE less than 0.1. However, usually underestimated over Arctic, especially wet conditions late spring early summer. Moreover, was typically higher winter autumn, summer, spring. Specifically, polluted dust (PD), dust, clean marine (CM) dominant types spring, winter, while ES (elevated smoke) from frequent wildfires reached highest FoOs. There increasing trends FoOs CM decreasing PD, PC (polluted continental), DM (dusty marine) due to amplification. In general, vertical patterns showed little seasonal variation, but their horizontal at various altitudes varied by season. Furthermore, locally sourced such as Greenland, PD eastern Siberia, middle Siberia can spread surrounding areas accumulate further north, affecting broader region

Language: Английский

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Estimates of the Frequency of Synoptic Variations in Aerosol Characteristics in the Arctic Atmosphere and the Contribution of Various Pollutants to Anomalously High Aerosol Concentrations

Atmospheric and Oceanic Optics, Journal Year: 2025, Volume and Issue: 38(1), P. 69 - 76

Published: Feb. 1, 2025

Language: Английский

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Impact of wildfire smoke on Arctic cirrus formation – Part 1: Analysis of MOSAiC 2019–2020 observations

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(9), P. 4847 - 4866

Published: May 9, 2025

Abstract. The potential impact of wildfire smoke on Arctic cirrus formation is discussed based lidar and radar observations during the winter half year 1-year MOSAiC (Multidisciplinary drifting Observatory for Study Climate) expedition. Aerosol ice cloud were performed aboard icebreaker Polarstern at latitudes > 85° N. Aged Siberian polluted tropopause region over central entire 2019–2020. particle surface area concentration was order 5–15 µm2 cm−3 indicated considerably enhanced levels aerosol pollution more than 6 months. Numerous systems with cloud-top temperatures between −60 −75 °C developed in upper troposphere. We analyzed all layers respect to their geometrical optical properties a subgroup 20 events water content (IWC) crystal number (ICNC). In individual fallstreaks that are connected nucleation events, ICNCs typically ranged from 1 10 crystals L−1 but frequently also as high 20–50 L−1; however, 100 rare. Three observational facts corroborate our hypothesis significantly influenced formation: (1) occurrence long-lasting, persistent layer troposphere so favorable conditions heterogeneous particles always given and, same time, homogeneous freezing background probably widely suppressed; (2) concentrations, which enough trigger (as shown Part 2, companion paper this article; Ansmann et al., 2025); (3) found maximum saturation ratios 1.3–1.5, point dominance processes, initiated by inefficient ice-nucleating (INPs), expected when aged (i.e., organic particles) serve INPs. studies continued simulation portion work (Part 2; 2025).

Language: Английский

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