Variability of Eastern North Atlantic Summertime Marine Boundary Layer Clouds and Aerosols Across Different Synoptic Regimes Identified With Multiple Conditions

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(4)

Published: Feb. 12, 2025

Abstract This study estimates the meteorological covariations of aerosol and marine boundary layer (MBL) cloud properties in eastern North Atlantic (ENA) region, characterized by diverse synoptic conditions. Using a deep‐learning‐based clustering model with mid‐level surface daily data, we identify seven distinct regimes during summer from 2016 to 2021. Our analysis, incorporating reanalysis data satellite retrievals, shows that aerosols MBL clouds exhibit clear regime‐dependent characteristics, whereas lower tropospheric do not. discrepancy likely arises determined large‐scale conditions, which may overlook air mass histories predominantly dictate Focusing on three dominated northerly winds, analyze Atmospheric Radiation Measurement Program (ARM) ENA observations Graciosa Island Azores. In subtropical anticyclone regime, fewer cumulus more single‐layer stratocumulus light drizzle are observed, along highest droplet number concentration (Nd), condensation nuclei (CCN) levels. The post‐trough regime features broken or multi‐layer slightly higher rain rate, Nd CCN weak trough is deepest clouds, primarily strongest rate lowest Nd, levels, indicating strong wet scavenging. These findings highlight importance considering covariation driven when assessing indirect effects using observations.

Language: Английский

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Analysis of Contrasting Aerosol Indirect Effects in Liquid Water Clouds over the Northern Part of Arabian Sea

Atmospheric Environment, Journal Year: 2025, Volume and Issue: unknown, P. 121123 - 121123

Published: Feb. 1, 2025

Language: Английский

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Evaluation of aerosol–cloud interactions in E3SM using a Lagrangian framework

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(4), P. 2789 - 2812

Published: March 2, 2023

Abstract. A Lagrangian framework is used to evaluate aerosol–cloud interactions in the U.S. Department of Energy's Energy Exascale Earth System Model (E3SM) version 1 (E3SMv1) for measurements taken at Graciosa Island Azores where a Atmosphere Radiation Measurement (ARM) site located. This uses direct cloud condensation nuclei (CCN) concentration (instead relying on satellite retrievals aerosol optical depth) and incorporates suite ground-based ARM measurements, retrievals, meteorological reanalysis products that when applied over 1500 trajectories provides key insights into evolution low-level clouds radiative forcing not feasible from traditional Eulerian analysis framework. Significantly lower concentrations (40 %) surface CCN are measured precipitation rates 48 h back average above 1.2 mm d−1 Integrated Multi-satellitE Retrievals Global Precipitation (IMERG) product. The depletion elevated nearly twice as large observations compared E3SMv1 simulations. model bias remains significant despite modifying autoconversion accretion warm clouds. As associated with larger surface-based advect away Island, they maintain higher values droplet number (Nd) multiple days E3SM simulations start concentrations. response robust even after controlling factors such troposphere stability, degree coupling surface, island wake effects. simulates multi-day effect Twomey within 30 % observations. However, mean more than 2–3 times While effects similar amongst sensitivity experiments, liquid water path fraction adjustments positive using regression opposed negative present-day minus pre-industrial emissions approach. result suggests tuning alone unlikely produce desired susceptibilities E3SMv1.

Language: Английский

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Daytime variation in the aerosol indirect effect for warm marine boundary layer clouds in the eastern North Atlantic

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(5), P. 2913 - 2935

Published: March 6, 2024

Abstract. Warm boundary layer clouds in the eastern North Atlantic region exhibit significant diurnal variations cloud properties. However, cycle of aerosol indirect effect (AIE) for these remains poorly understood. This study takes advantage recent advancements spatial resolution geostationary satellites to explore daytime variation AIE by estimating susceptibilities changes droplet number concentration (Nd). Cloud retrievals month July over 4 years (2018–2021) from Spinning Enhanced Visible and Infrared Imager (SEVIRI) on Meteosat-11 this are analyzed. Our results reveal a “U-shaped” liquid water path (LWP), albedo, fraction. Clouds found be more susceptible Nd perturbations at noon less morning evening. The magnitude sign depend heavily state defined LWP precipitation conditions. Non-precipitating thin account 44 % all warm July, they contribute most observed variation. thick least frequent (10 %), negative albedo compared clouds. Precipitating dominant (46 but their show minimal throughout day. We find evidence that non-precipitating is influenced combination transition between “lagged” responses perturbations. fraction susceptibility can attributed morphology (e.g., overcast or broken). dissipation development do not adequately explain susceptibilities. Additionally, primarily driven intensity response rather than frequency occurrence states. imply polar-orbiting with an overpass time 13:30 LT underestimate mean values susceptibility, as observe daily minima region.

Language: Английский

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A Climatology of Midlatitude Maritime Cloud Fraction and Radiative Effect Derived from the ARM ENA Ground-Based Observations

Journal of Climate, Journal Year: 2022, Volume and Issue: 36(2), P. 531 - 546

Published: Oct. 5, 2022

Abstract More than four years of ground-based measurements taken at the ARM Eastern North Atlantic (ENA) site between July 2015 and September 2019 have been collected processed in this study. Monthly hourly means clear-sky, all-sky, total cloud fraction (CF T ), single-layered low L ) high H clouds, impacts all scene types on surface radiation budget (SRB), their radiative effects (CREs) examined. The annual averages CF , are 0.785, 0.342, 0.123, respectively. SW (LW) CREs for sky, total, low, clouds −56.7 (37.7), −76.6 (48.5), −73.7 (51.4), −26.8 (13.9) W m −2 respectively, resulting NET −19.0, −28.0, −22.2, −12.9 . Comparing properties both ENA Southern Great Plains (SGP) sites, we found that clear-sky downwelling LW fluxes two sites similar to each other due atmospheric background. Compared SGP, lower all-sky higher caused by its precipitable water vapor (PWV). With different microphysical condensation nuclei much optical depth SGP plays an important role determining flux, while b PWV flux surface. A sensitivity study has shown more sensitive (−1.07 % −1 (−0.689 with same conclusion (0.735 vs 0.318 ENA). results over shed new light midlatitude budgets, ocean land.

Language: Английский

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Insights of warm-cloud biases in Community Atmospheric Model 5 and 6 from the single-column modeling framework and Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) observations

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(15), P. 8591 - 8605

Published: Aug. 4, 2023

Abstract. There has been a growing concern that most climate models predict precipitation is too frequent, likely due to lack of reliable subgrid variability and vertical variations in microphysical processes low-level warm clouds. In this study, the warm-cloud physics parameterizations singe-column configurations NCAR Community Atmospheric Model version 6 5 (SCAM6 SCAM5, respectively) are evaluated using ground-based airborne observations from Department Energy (DOE) Radiation Measurement (ARM) Aerosol Cloud Experiments Eastern North Atlantic (ACE-ENA) field campaign near Azores islands during 2017–2018. The 8-month single-column model (SCM) simulations show both SCAM6 SCAM5 can generally reproduce marine boundary layer cloud structure, major macrophysical properties, their transition. improvement properties (CAM5 CAM6) be found through comparison with observations. Meanwhile, physical schemes underestimate liquid water content, droplet size, rain content but overestimate surface rainfall. Modeled condensation nuclei (CCN) concentrations comparable aircraft-observed ones summer overestimated by factor 2 winter, largely biases long-range transport anthropogenic aerosols like sulfate. We also test newly recalibrated autoconversion accretion account for size. Compared observations, more significant than SCAM6. This result explained introduction CAM6 microphysics, which further suppresses scheme's sensitivity individual warm-rain parameters. predicted susceptibilities CCN perturbations within reasonable range, indicating progress since CAM5 produces an aerosol indirect effect strong. present study emphasizes importance understanding combining SCM situ

Language: Английский

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Aerosol-induced closure of marine cloud cells: enhanced effects in the presence of precipitation

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(11), P. 6455 - 6476

Published: June 3, 2024

Abstract. The Weather Research Forecasting (WRF) version 4.3 model is configured within a Lagrangian framework to quantify the impact of aerosols on evolving cloud fields. Kilometer-scale simulations utilizing meteorological boundary conditions are based 10 case study days offering diverse meteorology during Aerosol and Cloud Experiments in Eastern North Atlantic (ACE-ENA). Measurements from aircraft, ground-based Atmosphere Radiation Measurement (ARM) site at Graciosa Island Azores, A-Train geostationary satellites utilized for validation, demonstrating good agreement with WRF-simulated aerosol properties. Higher concentration leads suppressed drizzle increased water content all days. These changes lead larger radiative cooling rates top, enhanced vertical velocity variance, horizontal wind speed near base lower-tropospheric inversion. As result, marine cell area expands, narrowing gap between shallow clouds increasing optical thickness, liquid content, top-of-atmosphere outgoing shortwave flux. While similar effects observed lightly non-raining clouds, they tend be smaller by comparison. show relationship expansion adjustments caused path fraction changes. positive scale as 74 % 51 %, respectively, relative Twomey effect. higher-resolution large-eddy may provide improved representation cloud-top mixing processes, these results emphasize importance addressing mesoscale cloud-state transitions quantification forcing that cannot attained traditional climate models.

Language: Английский

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Competition response of cloud supersaturation explains diminished Twomey effect for smoky aerosol in the tropical Atlantic

Proceedings of the National Academy of Sciences, Journal Year: 2025, Volume and Issue: 122(13)

Published: March 24, 2025

The Twomey effect brightens clouds by increasing aerosol concentrations, which activates more droplets and decreases cloud supersaturation in response to competition for water vapor. To quantify this response, we used marine low observations clean smoky conditions at Ascension Island the tropical South Atlantic during Layered Aerosol Smoke Interactions with Cloud (LASIC) campaign. These show similar increases droplet number increased accumulation-mode particles from surface-based satellite retrievals, demonstrating importance of below-cloud measurements retrieving aerosol–cloud interactions (ACI) conditions. Four methods estimating were compared, scene-based parcel-based showing sufficient variability a strong dependence on both accumulation concentration cloud-base updraft velocities. Decomposing aerosol-related changes albedo optical depth shows calculated accounts dampening activation 12 35%, explaining diminished high concentrations observed LASIC previously around world. This result was consistent independent retrievals condensation nuclei multimode size-resolving Lagrangian methods. Translating effects local radiative forcing as proxy preindustrial present-day showed that reduces cooling providing an essential process-specific constraint improving representation climate model simulation indirect forcing.

Language: Английский

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Evaluation of liquid cloud albedo susceptibility in E3SM using coupled eastern North Atlantic surface and satellite retrievals

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(20), P. 13523 - 13553

Published: Oct. 27, 2023

Abstract. The impact of aerosol number concentration on cloud albedo is a persistent source spread in global climate predictions due to multi-scale, interactive atmospheric processes that remain difficult quantify. We use 5 years geostationary satellite and surface retrievals at the US Department Energy (DOE) Atmospheric Radiation Measurement (ARM) eastern North Atlantic (ENA) site Azores evaluate representation liquid susceptibility for overcast scenes DOE Exascale Earth System Model version 1 (E3SMv1) provide possible reasons model–observation discrepancies. overall distribution 0.2 % CCN values reasonably simulated, but simulated water path (LWP) lower than observed layer mean droplet (Nd) comparisons are highly variable depending Nd retrieval technique. E3SMv1's greater given LWP effective radius observed. However, response suppressed correlation between solar zenith angle (SZA) created by seasonal cycle not Controlling this effect examining optical depth (COD) shows COD For surface-based retrievals, only true after controlling adiabaticity because adiabaticities much Assuming constant as done top-of-atmosphere (TOA) narrows retrieved ln distribution, which increases sensitivity match TOA sensitivity. caused Twomey TOA-retrieved Nd, once differences removed, also surface-retrieved Nd. E3SMv1 negative Despite reproducing LWP–Nd relationship, clouds become more adiabatic increases, while do not, associated with heavily precipitating partially completely deeper weaker inversions E3SMv1. These property indicate relationship likely same mechanisms observations. fails mute excessively strong effect, highlighting potentially important confounding factor effects render non-causal. scales assumptions, particularly related adiabaticity, contribute substantial spreads comparisons, though enough consistency exists suggest activation, drizzle, entrainment critical areas focus development improving fidelity aerosol–cloud interactions E3SM.

Language: Английский

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Measurement report: A comparison of ground-level ice-nucleating-particle abundance and aerosol properties during autumn at contrasting marine and terrestrial locations

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(9), P. 5433 - 5456

Published: May 8, 2024

Abstract. Ice-nucleating particles (INPs) are an essential class of aerosols found worldwide that have far-reaching but poorly quantified climate feedback mechanisms through interaction with clouds and impacts on precipitation. These can highly variable physicochemical properties in the atmosphere, it is crucial to continuously monitor their long-term concentration relative total ambient aerosol populations at a wide variety sites comprehensively understand aerosol–cloud interactions atmosphere. Hence, our study applied situ forced expansion cooling device measure INP concentrations test its automated continuous measurements atmospheric observatories, where complementary instruments heavily equipped. Using collocated size, number, composition from these sites, we analyzed correlation between sources abundance INPs different environments. Toward this aim, measured ground-level two contrasting one Southern Great Plains (SGP) region United States substantial terrestrially influenced population Eastern North Atlantic Ocean (ENA) primarily marine-influenced population. examined mainly formed immersion freezing were performed ≤ 12 min resolution range heterogeneous temperatures (Ts above −31 °C) for least 45 d each site. The associated data analysis was conducted consistent manner. We also explored additional offline characterization particle samples both locations comparison data. From ENA data, average, ranges ≈ 1 20 L−1 (−30 °C T −20 during October–November 2020. Backward air mass trajectories reveal strong marine influence 75.7 % masses originating over 96.6 traveling open water, chemistry suggests source besides maritime (e.g., sea spray aerosols) ENA. In contrast, 90.8 SGP location originated American continent, 96.1 time, traveled land. As result, organic-rich terrestrial exhibited notably high 100 −15 2019. probability density function surface area-scaled efficiency (ice nucleation active site density; ns) assessed selected temperatures. While higher than those ENA, ns(T) values (≈ 105 107 m−2 −30 reciprocally lower approximately 2 orders magnitude 109 °C). observed difference stems varied available areas, Saer, (Saer,SGP > Saer,ENA). parameterizations developed as periods.

Language: Английский

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