A first global height-resolved cloud condensation nuclei data set derived from spaceborne lidar measurements

Earth system science data, Journal Year: 2023, Volume and Issue: 15(8), P. 3747 - 3760

Published: Aug. 22, 2023

Abstract. We present a global multiyear height-resolved data set of aerosol-type-specific cloud condensation nuclei concentrations (nCCN) estimated from the spaceborne lidar aboard Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. For estimating nCCN, we apply recently introduced Optical Modelling CALIPSO Aerosol Microphysics (OMCAM) algorithm to Level 2 Profile product. The nCCN are then gridded into uniform latitude–longitude grid 2∘×5∘, vertical resolution 60 m surface an altitude 8 km, temporal 1 month. span total 186 months, June 2006 December 2021. In addition, provide 3D climatology produced using complete time series. further highlight some potential applications in context aerosol–cloud interactions. can be accessed at https://doi.org/10.1594/PANGAEA.956215 (Choudhury Tesche, 2023).

Language: Английский

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Contributions of the synoptic meteorology to the seasonal cloud condensation nuclei cycle over the Southern Ocean

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(4), P. 2631 - 2648

Published: Feb. 28, 2025

Abstract. Cloud condensation nuclei (CCN) play a fundamental role in determining the microphysical properties of low-level clouds that are crucial for defining energy budget over Southern Ocean (SO). However, many aspects CCN SO remains poorly understood, including synoptic meteorology. In this study, we classify six distinct regimes Kennaook / Cape Grim Observatory (CGO) and examine their influence on seasonal cycle concentration (NCCN). Three “winter” dominant when subtropical ridge (STR) is strong centered at lower latitudes, while three “summer” prevail STR shifts to higher latitudes. Distinct winter summer “baseline” patterns contribute NCCN, with baseline regime characterized by heavier precipitation (0.10 vs. 0.03 mm h−1), deeper boundary layer (850 900 hPa), NCCN (71 137 cm−3) than one. Across these two regimes, observe significant inverse relationship between underscoring contribution reducing SO. An analysis air mass back-trajectories, specifically free-troposphere level, supports distinction, wintertime masses originating more frequently from The summertime seen as barrier Antarctic reaching latitude CGO. Conversely, found pass continental Australia before CGO, consistent enhanced radon concentrations.

Language: Английский

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Biological enhancement of cloud droplet concentrations observed off East Antarctica

npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)

Published: March 20, 2025

Language: Английский

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MODIS Aerosol and Low‐Cloud Retrievals: Orographic Effects in the Wake of Macquarie Island

Earth and Space Science, Journal Year: 2025, Volume and Issue: 12(5)

Published: April 30, 2025

Abstract Visible/infrared imagery from passive satellites is commonly relied upon to study low cloud microphysics over oceanic regions, including for the Southern Ocean (SO), but relatively little validation has been undertaken SO. In this article, we compare low‐cloud effective radius ( r e ), droplet number concentration N d ) and liquid water path (LWP) retrievals NASA Moderate Imaging Spectroradiometer (MODIS) with surface measurements collected during Macquarie Island Cloud Radiation Experiment (MICRE). MODIS 3.7‐μm band show bias moderately good correlation relative MICRE liquid‐phase clouds when restricted Solar Zenith Angles <65° on spatial scales of 50–100 km. However, overall in 3.7 partly results cancellation errors: overestimated non‐to‐lightly precipitating clouds, underestimated heavier drizzling by ∼1–1.5 μm. 1.6‐μm 2.1‐μm are biased high. may likewise be slightly under‐ or depending concentration, there insufficient data provide confidence result. Interestingly, a composite 2002 2020 distinct region enhanced cover (and lower wake associated orographic formation. aerosol optical depth (AOD) Angstrom Exponent (AE) upwind downwind island do not differ significantly. Comparison suggests that Collection 6 AOD reasonable, while AE problematically large.

Language: Английский

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Southern Ocean cloud and shortwave radiation biases in a nudged climate model simulation: does the model ever get it right?

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(22), P. 14603 - 14630

Published: Nov. 17, 2022

Abstract. The Southern Ocean radiative bias continues to impact climate and weather models, including the Australian Community Climate Earth System Simulator (ACCESS). bias, characterised by too much shortwave radiation reaching surface, is attributed incorrect simulation of cloud properties, frequency phase. To identify regimes important Ocean, we use k-means histogram clustering, applied a satellite product then fitted nudged simulations latest-generation ACCESS atmosphere model. We instances when model correctly or incorrectly simulates same type as for any point in time space. evaluate biases these instances. find that type, property equivalent, some cases greater, magnitude remain compared types are simulated. Furthermore, even appear small on average, biases, such liquid ice water paths fractions, large. Our results suggest simply getting right (or macrophysics) not enough reduce bias. where small, it may be so wrong reasons. Considerable effort still required improve microphysics, with particular focus

Language: Английский

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Simultaneous organic aerosol source apportionment at two Antarctic sites reveals large-scale and ecoregion-specific components

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(10), P. 6305 - 6322

Published: May 29, 2024

Abstract. Antarctica and the Southern Ocean (SO) are most pristine areas of globe represent ideal places to investigate aerosol–climate interactions in an unperturbed atmosphere. In this study, we present submicrometer aerosol (PM1) source apportionment for two sample sets collected parallel at British Antarctic Survey stations Signy Halley during austral summer 2018–2019. Water-soluble organic matter (WSOM) is a major component both sites (37 % 29 water-soluble PM1, on average, Halley, respectively). Remarkable differences between pelagic (open-ocean) sympagic (influenced by sea ice) air mass histories related sources found. The application factor analysis techniques series spectra obtained means proton-nuclear magnetic resonance (H-NMR) spectroscopy samples allows identification five (OA) sources: primary (POA) types, characterized sugars, polyols, degradation products lipids associated with open-ocean sympagic/coastal waters, respectively; secondary (SOA) one enriched methanesulfonic acid (MSA) dimethylamine (DMA) waters other trimethylamine (TMA) linked environments; fifth unclear origin, possibly atmospheric aging emissions. Overall, our results strongly indicate that emissions from ecosystems affect variability composition study area, circulation establishing marked latitudinal gradients only some components (e.g., components) while distributing others and/or aged maritime inner regions.

Language: Английский

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Influences of Antarctic Ozone Depletion on Southern Ocean Aerosols

Journal of Geophysical Research Atmospheres, Journal Year: 2022, Volume and Issue: 127(18)

Published: Sept. 9, 2022

Abstract The Southern Ocean is often identified as a pristine aerosol environment, being distant from anthropogenic sources. We investigate anomalies in loading over the due to stratospheric ozone depletion historical simulations performed for sixth Coupled Model Intercomparison Project. explore direct influences of on aerosols via enhanced ultraviolet‐induced production oceanic dimethyl sulfide (DMS), and indirect changes Hemisphere westerly jet, which impacts wind‐driven fluxes. identify wind key driver change austral summertime aerosol, leading increases optical depth up 24% compared with pre–ozone hole era. In contrast previous studies, ultraviolet fluxes are less obvious. Our results show that environment cannot be considered representative conditions because has indirectly increased marine

Language: Английский

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Atmospheric oxidation impact on sea spray produced ice nucleating particles

Environmental Science Atmospheres, Journal Year: 2023, Volume and Issue: 3(10), P. 1513 - 1532

Published: Jan. 1, 2023

Ice nucleating particles (INPs) in sea spray aerosol (SSA) are important for ice formation clouds over oceans. We found that SSA INP concentrations during a phytoplankton bloom were degraded with exposure to 3 8 days of atmospheric oxidation.

Language: Английский

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Earth System Model Aerosol–Cloud Diagnostics (ESMAC Diags) package, version 1: assessing E3SM aerosol predictions using aircraft, ship, and surface measurements

Geoscientific model development, Journal Year: 2022, Volume and Issue: 15(10), P. 4055 - 4076

Published: May 25, 2022

Abstract. An Earth system model (ESM) aerosol–cloud diagnostics package is developed to facilitate the routine evaluation of aerosols, clouds, and interactions simulated by Energy Exascale System Model (E3SM) from US Department (DOE). The first version focuses on comparing aerosol properties with aircraft, ship, surface measurements, which are mostly measured in situ. currently cover six field campaigns four geographical regions: eastern North Atlantic (ENA), central (CUS), northeastern Pacific (NEP), Southern Ocean (SO). These regions produce frequent liquid- or mixed-phase extensive measurements available Atmospheric Radiation Measurement (ARM) program other agencies. Various types metrics performed for number, size distribution, chemical composition, cloud condensation nuclei (CCN) concentration, various meteorological quantities assess how well E3SM represents observed across spatial scales. Overall, qualitatively reproduces number composition reasonably well, but it overestimates Aitken-mode aerosols underestimates accumulation-mode over CUS ENA regions, suggesting that processes related particle growth coagulation might be too weak model. current struggles reproduce new formation events frequently both indicating missing parameterizations. coded organized a way can extended campaign datasets adapted higher-resolution simulations.

Language: Английский

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Emission Reductions Significantly Reduce the Hemispheric Contrast in Cloud Droplet Number Concentration in Recent Two Decades

Journal of Geophysical Research Atmospheres, Journal Year: 2023, Volume and Issue: 128(2)

Published: Jan. 7, 2023

Abstract Anthropogenic activities have drastically impacted the climate system since Industrial Revolution. However, to what extent anthropogenic emissions influence cloud droplet number concentration ( N d ), critical parameter for understanding aerosol‐cloud interactions, is poorly known on hemispheric scale due considerable retrieval uncertainty. We employed multiple widely used sampling methods evaluate long‐term trend in contrast (Δ d(NH‐SH) ) between Northern Hemisphere (NH) and Southern (SH). Here we show that Δ was halved from 2003 2020 using different channels, even though range of magnitudes large. Such dramatic changes are dominated by significantly decreased over NH (∼20%) emission reductions compared relatively stable pristine nature SH. Aerosol optical depth (AOD) aerosol index (AI) correlate with based trends, they replicate trends. This poor correlation partly contributed stratospheric smoke wildfires Australia had little The northwest Atlantic shows largest contribution, ∼38%, trend, whereas Pacific dominates change AOD AI, contributing more than 60% ∼50% AI NH. Our results imply reduced provide strong observational evidence extensively altered liquid clouds last two decades.

Language: Английский

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