Improving Prediction of Marine Low Clouds Using Cloud Droplet Number Concentration in a Convolutional Neural Network DOI Creative Commons
Yang Cao, Yannian Zhu, Minghuai Wang

et al.

Journal of Geophysical Research Machine Learning and Computation, Journal Year: 2024, Volume and Issue: 1(4)

Published: Nov. 30, 2024

Abstract Marine low clouds play a crucial role in cooling the climate, but accurately predicting them remains challenging due to their highly non‐linear response various factors. Previous studies usually overlook effects of cloud droplet number concentration (N d ) and non‐local information target grids. To address these challenges, we introduce convolutional neural network model (CNN Met‐Nd that uses both local includes N as cloud‐controlling factor enhance predictive ability daily cover, albedo, radiative (CRE) for global marine clouds. CNN demonstrates superior performance, explaining over 70% variance three variables scenes 1° × 1°, notable improvement past efforts. also replicates geographical patterns trends from 2003 2022. In contrast, similar without Met struggles predict long‐term properties effectively. Permutation importance analysis further highlights critical Met‐N 's success. Further comparisons with an artificial (ANN model, which same inputs considering spatial dependence, show performance R 2 values CRE being 0.16, 0.12, 0.18 higher, respectively. This incorporating information, at least on scale, into predictions climate parameterizations.

Language: Английский

Radiative forcing from the 2020 shipping fuel regulation is large but hard to detect DOI Creative Commons
Jianhao Zhang,

Yao‐Sheng Chen,

Edward Gryspeerdt

et al.

Communications Earth & Environment, Journal Year: 2025, Volume and Issue: 6(1)

Published: Jan. 13, 2025

Abstract Reduction in aerosol cooling unmasks greenhouse gas warming, exacerbating the rate of future warming. The strict sulfur regulation on shipping fuel implemented 2020 (IMO2020) presents an opportunity to assess potential impacts such emission regulations and detectability deliberate perturbations for climate intervention. Here we employ machine learning capture cloud natural variability estimate a radiative forcing +0.074 ±0.005 W m −2 related IMO2020 associated with changes shortwave effect over three low-cloud regions where routes prevail. We find low this event, attributed strong albedo cover. Regionally, is higher southeastern Atlantic stratocumulus deck. These results raise concerns that reductions emissions will accelerate warming proposed as marine brightening need be substantial order overcome detectability.

Language: Английский

Citations

1
Radiative forcing from aerosol–cloud interactions enhanced by large-scale circulation adjustments DOI Creative Commons
Guy Dagan,

Netta Yeheskel,

Andrew Williams

et al.

Nature Geoscience, Journal Year: 2023, Volume and Issue: 16(12), P. 1092 - 1098

Published: Nov. 20, 2023

Abstract The impact of anthropogenic aerosols on clouds is a leading source uncertainty in estimating the effect human activity climate system. challenge lies scale difference between (~1–10 km) and general circulation (>1,000 km). To address this, we use convection-permitting simulations conducted long narrow domain, to resolve convection while also including representation large-scale processes. We examine set that include sea surface temperature gradient—which drives circulation—and compare these with no gradient. show effective radiative forcing due aerosol–cloud interactions strongly enhanced by adjustments aerosol. find an increase aerosol concentration suppresses precipitation shallow-convective regions, which enhances water vapour transport portion domain dominated deep convection. subsequent latent heat release deep-convective regions strengthens overturning evaporation. These changes can explain cloudiness under higher concentrations and, consequently, large effect. This work highlights fundamental importance understanding from interactions.

Language: Английский

Citations

19
Thin Clouds Control the Cloud Radiative Effect Along the Sc‐Cu Transition DOI Creative Commons
Goutam Choudhury, Tom Goren

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(10)

Published: May 14, 2024

Abstract In situ and spaceborne studies reveal the prevalence of thin clouds in major Stratocumulus‐to‐Cumulus Transition (SCT) regions. Using instantaneous satellite reanalysis data, this study investigates properties Southeast Pacific Ocean their impact on cloud radiative effect (CRE). Our findings demonstrate that are intrinsic to SCT. The overcast stratocumulus‐dominated regime exhibits a minimal presence clouds, which become notably prominent after breakup into cumulus‐dominated regime. dependence occurrence is also observed terms marine cold‐air outbreak parameter sea surface temperature. Thin at given cover significantly modulate shortwave (SW) longwave (LW) components CRE. SW CRE decreases by 46 %–65 % with increasing cover. They account for larger variance albedo than combined influence liquid water path effective radius. Furthermore, LW about 12 %–52 An increase fraction leads negative offset positive This compensation ranges from approximately 8 as much 19 50 These elucidate crucial role thus morphology, modulating underscore necessity accurate representation climate models.

Language: Английский

Citations

4
More biomass burning aerosol is being advected westward over the southern tropical Atlantic since 2003 DOI Creative Commons
Tyler Tatro, Paquita Zuidema

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 965, P. 178506 - 178506

Published: Jan. 30, 2025

Language: Английский

Citations

0
Increased Occurrence of Stratiform Clouds in the Caribbean Dry Season Since 1971 From Surface Observations DOI Creative Commons
Ryan Eastman, Isabel L. McCoy, Paquita Zuidema

et al.

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

Published: Feb. 12, 2025

Abstract This study examines low cloud trends over 1971–2020 by utilizing a unique, surface based record generated human observers at Caribbean island weather stations. In the dry season (December–April), when clouds dominate behavior in Caribbean, Stratocumulus frequency increases expense of Cumulus clouds. Low cover varies positively with and exhibits slight increasing trend. Rainfall frequency, observed subset co‐located stations, corroborating their Trends temperature humidity show stronger warming aloft compared to drying levels. are shown respond latent heat flux inversion this region. These results suggest that could be driven moisture fluxes into more strongly capped boundary layer. Increased wintertime precipitation may represent de‐amplifying feedback drying. Climate indices such as North Atlantic Oscillation ENSO do not significant relationships variability, nor variations aerosol concentration.

Language: Английский

Citations

0
Constraining aerosol–cloud adjustments by uniting surface observations with a perturbed parameter ensemble DOI Creative Commons
August Mikkelsen, Daniel T. McCoy, Trude Eidhammer

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(8), P. 4547 - 4570

Published: April 25, 2025

Abstract. Aerosol–cloud interactions (ACIs) are the largest source of uncertainty in inferring magnitude future warming consistent with observational record. The effective radiative forcing due to ACI (ERFaci) is dominated by liquid clouds and composed two terms: change cloud albedo redistributing over a larger number droplets (Nd) macrophysical properties changes microphysics. These terms are, respectively, referred as (RFaci) aerosol–cloud adjustments. While RFaci uncertain, its sign confidently negative results cooling historical In contrast, adjustment water path (LWP) enhanced Nd associated uncertain sign. Increased LWP response increased precipitation suppression, while decreased evaporation from top. Observational constraints these processes poor part because causal ambiguity relationship between LWP. To better understand this relationship, (P), Nd, surface observations Eastern North Atlantic (ENA) atmospheric observatory combined output perturbed parameter ensemble (PPE) hosted Community Atmosphere Model version 6 (CAM6). This allows for interpretation observed covariability. Observations ENA constrain range possible adjustments relative prior PPE 15 %, resulting global value that positive (a cooling) ranging 2.1 6.9 g m−2. It found covariability coalescence scavenging not strongly related

Language: Английский

Citations

0
Aerosol trends dominate over global warming-induced cloud feedback in driving recent changes in marine low clouds DOI Creative Commons
Yang Cao, Hao Wang, Yannian Zhu

et al.

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 13, 2025

Abstract Over the past two decades, anthropogenic emission reductions and global warming have impacted marine low clouds through aerosol-cloud interactions (ACI) cloud feedback, yet their quantitative contributions remain unclear. This study employs a deep learning model (CNNMet−Nd) Community Earth System Model version 2 (CESM2) to disentangle these effects. CNNMet−Nd reveals that aerosol-driven changes in droplet number concentration dominate near-global shortwave radiative effect (ΔCRE), contributing 0.42 ± 0.08 Wm⁻² per 20 years, compared 0.05 0.37 from feedback. CESM2 effectively reproduces predominant influence of aerosol on ΔCRE by CNNMet−Nd, lending us confidence for stronger estimate effective forcing due ACI (ERFaci) -1.29 since preindustrial era. These findings highlight critical role shaping trends its broader climate implications, especially under ongoing reduction efforts.

Language: Английский

Citations

0
A new method for diagnosing effective radiative forcing from aerosol–cloud interactions in climate models DOI Creative Commons
Brandon M. Duran, Casey J. Wall, Nicholas J. Lutsko

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(4), P. 2123 - 2146

Published: Feb. 19, 2025

Abstract. Aerosol–cloud interactions (ACIs) are a leading source of uncertainty in estimates the historical effective radiative forcing (ERF). One reason for this is difficulty estimating ERF from aerosol–cloud (ERFaci) climate models, which typically requires multiple calls to radiation code. Most commonly used methods also cannot disentangle contributions different processes ERFaci. Here, we develop new, computationally efficient method shortwave (SW) ERFaci liquid clouds using histograms monthly averaged cloud fraction partitioned by droplet radius (re) and water path (LWP). Multiplying with SW kernels gives total clouds, can be decomposed into Twomey effect, LWP adjustments, (CF) adjustments. We test data five CMIP6-era Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument simulator generate histograms. Our similar other established regions prevalent indicates that CF adjustments have contributed −0.34 ± 0.23, −0.22 0.13, −0.09 0.11 W m−2, respectively, since 1850 ensemble mean (95 % confidence). These results demonstrate widespread adoption MODIS re–LWP joint histogram diagnostic would allow its components quickly accurately diagnosed model outputs, crucial step reducing ERF.

Language: Английский

Citations

0
Diurnal evolution of non-precipitating marine stratocumuli in a large-eddy simulation ensemble DOI Creative Commons

Yao‐Sheng Chen,

Jianhao Zhang, Fabian Hoffmann

et al.

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(22), P. 12661 - 12685

Published: Nov. 14, 2024

Abstract. We explore the cloud system evolution of non-precipitating marine stratocumuli with a focus on impacts diurnal cycle and free-tropospheric (FT) humidity based an ensemble 244 large-eddy simulations generated by perturbing initial thermodynamic profiles aerosol conditions. Cases are categorized their degree decoupling liquid water path (LWPc, model columns optical depths greater than one). A budget analysis method is proposed to analyze in both coupled decoupled boundary layers. More clouds start relatively low LWPc fraction (fc) but experience least decrease fc during daytime. undergo daytime reduction fc, especially those higher at sunrise because they suffer from faster weakening net radiative cooling. During nighttime, positive correlation between FT emerges, consistent reducing cooling jump, which reduce entrainment increase LWPc. The more likely nighttime for larger inversion base height (zi), conditions under dominates as turbulence develops. In morning, rate depends sunrise, zi, decoupling, distinct contributions subsidence radiation.

Language: Английский

Citations

0
Revisiting Aerosol–Cloud Interactions From Weekly Cycles DOI Creative Commons
Hailing Jia, Otto Hasekamp, Johannes Quaas

et al.

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(13)

Published: July 9, 2024

Abstract Weekly cycles (WCs) in cloud properties have been reported and linked to aerosol effects. Yet the extent which human activities contribute their occurrence remains unclear. Here, we revisit aerosol–cloud interactions from WCs over central Europe using long‐term satellite reanalysis data. Significant droplet number concentration ( N d ) are detected with minima/maxima on Monday/Friday, indicating a clear signal of Twomey effect. Notably, –to–aerosol sensitivity is found decrease at larger concentrations, confirming nonlinear behavior aerosol– relation (in log–log space) previously, but distinct perspective. Nevertheless, no discernible liquid water path found. The pronounced cover demonstrated be driven by natural variability. Our results indicate that offer useful pathway for investigating effect, not as effective detecting adjustments.

Language: Английский

Citations

0