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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Climate change, water and agriculture linkages in the upper Indus basin: A field study from Gilgit-Baltistan and Leh-Ladakh

Frontiers in Sustainable Food Systems, Journal Year: 2023, Volume and Issue: 6

Published: Jan. 10, 2023

The Indus is one of three largest river systems emerging from the Hindu-Kush Himalaya (HKH). In Upper Basin (UIB), water resources, agriculture and livelihoods are highly vulnerable to climate change induced hazards risks. Present study investigates impacts on availability, based perception data collected through focus group discussions key informant interviews selected sites in Gilgit-Baltistan Leh-Ladakh subregions UIB. Findings revealed that inducing both direct indirect agriculture, livelihoods. Local people reported changes precipitations patterns, temperature timing seasons, increased incidence crop pest attacks resulting decline livestock productivity (direct impacts). Climate also impacting indirectly degradation rangelands/pastures variability traditional irrigation systems. taking diverse adaptation measures cope with impacts. These include revival less intensive crops, start enterprises value chain developments Gilgit-Baltistan, improvement management practices integration agricultural products tourism Leh-Ladakh. Some likely have negative sustainability local agriculture. For instance, inorganic unplanned shift crops improved breeds Based findings, this suggests establishing a learning mechanism for communities collaboration institutions sides border connections.

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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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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Exploring Causal Relationships and Adjustment Timescales of Aerosol‐Cloud Interactions in Geostationary Satellite Observations and CAM6 Using Wavelet Phase Coherence Analysis

Geophysical Research Letters, Journal Year: 2025, Volume and Issue: 52(2)

Published: Jan. 23, 2025

Abstract We present for the first time within cloud physics context, application of wavelet phase coherence analysis to disentangle counteracting physical processes associated with lead‐lag difference between cloud‐proxy liquid water path (LWP) and aerosol‐proxy droplet number concentration ( N d ) in an Eulerian framework using satellite‐based observations climate model outputs. This approach allows us identify causality dominant adjustment timescales governing correlation LWP . Satellite indicate a more prevalent positive daytime regardless whether leads or lags The response, precipitation processes, typically occurs 1 hr, while negative response resulting from entrainment drying, usually takes 2–4 hr. CAM6 displays excessively rapid responses along overly strong insufficient leading compared observations.

Language: Английский

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Mesoscale Cellular Convection Detection and Classification Using Convolutional Neural Networks: Insights From Long‐Term Observations at ARM Eastern North Atlantic Site

Journal of Geophysical Research Machine Learning and Computation, Journal Year: 2025, Volume and Issue: 2(1)

Published: March 1, 2025

Abstract Marine boundary layer clouds are crucial in Earth's climate system. They frequently manifest as closed or open cell mesoscale cellular convection (MCC). MCC challenging to represent accurately current models, highlighting the need for detailed observational data sets and in‐depth analyses. This study utilizes over 8 years of observations from U.S. Department Energy (DOE) Atmospheric Radiation Measurement (ARM) User Facility Eastern North Atlantic (ENA) site at Graciosa Island, Azores, investigate these clouds. We first apply a convolutional neural network with U‐Net architecture classify cells, marking application such an approach automatically detecting patterns ground‐based radar measurements. method addresses some gaps satellite related low temporal resolution, nighttime challenges, limited vertical structure capture. The analysis cases shows clear differences between MCCs: Closed characterized by lower cloud tops bases, shallower geometrical depth, weaker horizontal wind speeds, stronger atmospheric stability, more homogeneous liquid water path than MCCs. Finally, we demonstrate two potential applications our radar‐based classifications: (a) facilitating investigation aerosol‐cloud interactions (b) exploring meteorological factors along MCC's evolution integrating imagery back‐trajectory analysis. identified offer valuable resource scientific community processes further improve model accuracy.

Language: Английский

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Diurnal variation of aerosol indirect effect for warm marine boundary layer clouds in the eastern north Atlantic

Published: Aug. 23, 2023

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 AIE by estimating susceptibilities changes droplet number concentration (Nd). Cloud retrievals four months July (2018–2021) from SEVIRI on Meteosat-11 over this are analyzed. Our results reveal a "U-shaped" daytime liquid water path (LWP), albedo, and 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 they contribute most observed variation. thick least frequent (10 %), negative albedo compared clouds. Precipitating dominant (46 but their show minimal variation throughout day. We find evidence that non-precipitating 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, is primarily driven intensity response rather than frequency occurrence states. imply polar-orbiting with overpass time 13:30 local underestimate mean value susceptibility, as observe daily minima region.

Language: Английский

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Tracing the physical signatures among the calculated global clear-sky spectral shortwave radiative flux distribution

Journal of Quantitative Spectroscopy and Radiative Transfer, Journal Year: 2024, Volume and Issue: 328, P. 109167 - 109167

Published: Aug. 23, 2024

Language: Английский

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Tracing the Physical Signatures Among the Calculated Global Clear-Sky Spectral Shortwave Radiative Flux Distribution

Published: Jan. 1, 2024

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Language: Английский

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Exploring causal relationships and adjustment timescales of cloud-aerosol interactions in geostationary satellite observations and CAM6 using wavelet phase coherence analysis

Authorea (Authorea), Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 25, 2024

We present for the first time within cloud physics context, application of wavelet phase coherence analysis to disentangle counteracting physical processes associated with lead-lag difference between liquid water path (LWP) and droplet number concentration (Nd) in an Eulerian framework using satellite-based observations climate model outputs. This approach allows us identify causality typical adjustment timescales governing correlation LWP Nd. Satellite indicate a more prevalent positive daytime Nd regardless whether leads or lags The response, precipitation processes, typically occurs 1 hour, while negative response resulting from entrainment drying, usually takes 2-4 hours. CAM6 displays excessively rapid responses along overly strong insufficient leading compared observations.

Language: Английский

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