Is a more physical representation of aerosol chemistry needed for fog forecasting?

Quarterly Journal of the Royal Meteorological Society, Journal Year: 2024, Volume and Issue: 150(762), P. 2690 - 2711

Published: June 24, 2024

Abstract With the changing climate, study of fog formation is essential due to impact complexity natural and anthropogenic aerosols. The evolution droplet size distribution in presence different aerosol species remains poorly understood. To make progress towards reducing uncertainty forecasts, Eulerian–Lagrangian particle‐based small‐scale model for diffusional growth droplets used better understand activation growth. simulations are performed using observed data from Winter Fog Experiment over Indira Gandhi International Airport, New Delhi. microphysical properties, such as number concentrations (Nd) liquid water content (LWC), important simulation, evaluated gain more insights. have shown properties at evolutionary stages. Nd effective radius change with variations LWC chemistries (i.e., organics, mix, inorganic). calculated visibility small scale also variation LWC. This compared an existing parametrization parcel–direct numerical simulation calculation. hygroscopicity , which highly related aerosols condensation nuclei, taken into account demonstrate contribution chemistry formation. results highlight that prediction regulated by species.

Language: Английский

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Cloud microphysical response to entrainment of dry air containing aerosols

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

Published: Jan. 8, 2025

Impacts of aerosol particles on clouds, precipitation, and climate remain one the significant uncertainties in change. Aerosol entrained at cloud top edge can affect microphysical macrophysical properties, but process is still poorly understood. Here we investigate responses to entrainment aerosol-laden air Pi convection-cloud chamber. Results show that droplet number concentration increases mean radius droplets decreases, which leads narrower size distribution smaller relative dispersion. These behaviors are generally consistent with scenario expected from first aerosol-cloud indirect effect for a constant liquid water content (L). However, L significantly these experiments. Such enhancement be understood as suppression sedimentation removal due small droplets. Further, an increase reduces effective ultimately optical thickness albedo, making clouds brighter. findings relevance interface stratocumulus top, where modeling studies have suggested plays strong role regulating L. Therefore, results provide insights into impacts cloud, climate.

Language: Английский

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轻量型成像式云粒子探测器定标及观测研究

Acta Optica Sinica, Journal Year: 2025, Volume and Issue: 45(6), P. 0604001 - 0604001

Published: Jan. 1, 2025

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Impact of Improved Surface Flux Parameterization on Simulation of Radiation Fog Formation in the Yangtze River Delta, China

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(9)

Published: April 30, 2025

Abstract Meteorological conditions within the boundary layer play significant roles in radiation fog formation, which typically occur under stable conditions. The stratification surface are represented by stability parameter ( ζ ), calculated as ratio of reference height z to Monin‐Obukhov length L (i.e., = / ). Current schemes exhibit uncertainties strong > 1). Grachev2007 scheme for 1 and Li2014 Li2015 calculating implemented into Weather Research Forecasting model coupled with Chemistry (WRF‐Chem). Two successive events Yangtze River Delta simulated compare improved default scheme. Both high‐pressure characterized clear sky light wind during nighttime. results indicate that dominate before improves threat scores formation. Regarding flux, due reduced thermal resistance parameterization, increased heat exchange enhances cooling from sensible flux 1, is conducive turbulent mixing, dynamic drag reduces speed 1. This weakens contribution shear kinetic energy, ultimately promoting findings this paper applicable simulations other regions, such plain areas covered grassland, cropland, or vegetation, providing support improving simulation.

Language: Английский

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Impacts of forest cover change on carbon stock, carbon emission and land surface temperature in Sor watershed, Baro Akobo Basin, Western Ethiopia

Journal of Water and Climate Change, Journal Year: 2023, Volume and Issue: 14(8), P. 2842 - 2860

Published: July 24, 2023

Abstract Human-induced actions aggravate forest degradation and result in carbon emissions. Increment of emission raises land surface temperature (LST) contributes to climate change. The aim this study was assess the impacts cover change on stocks, emissions LST over period 1992–2022 using geospatial techniques Sor watershed, Western Ethiopia. results revealed that declined by 336.6 km2 due expansion agricultural with an area 274.9 km2. Results show a decline stock 58,883.4 tons/km2 while annual exhibited increasing trend 2,418,083.91 tons atmosphere past three decades. As vegetation declined, increased average 3.7 °C All actors, including government non-governmental organizations, should contribute tree planting reafforestation programmes minimize Furthermore, we need build climate-resilient green economy protect people from negative

Language: Английский

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The air we breathe: An In-depth analysis of PM2.5 pollution in 1312 cities from 2000 to 2020

Environmental Science and Pollution Research, Journal Year: 2023, Volume and Issue: 30(41), P. 93900 - 93915

Published: July 31, 2023

Language: Английский

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Predicting the Impact of Change in Air Quality Patterns Due to COVID-19 Lockdown Policies in Multiple Urban Cities of Henan: A Deep Learning Approach

Atmosphere, Journal Year: 2023, Volume and Issue: 14(5), P. 902 - 902

Published: May 22, 2023

Several countries implemented prevention and control measures in response to the 2019 new coronavirus virus (COVID-19) pandemic. To study impact of lockdown due COVID-19 on multiple cities, this utilized data from 18 cities Henan understand air quality pattern change during 2021. It examined temporal spatial distribution impact. This firstly a deep learning bi-directional long-term short-term (Bi-LSTM) model predict patterns 3 periods, i.e., COVID-A (before COVID-19, 2019), COVID-B (during 2020), COVID-C (after cases, 2021) obtained R2 value more than 72% average each year decreased MAE value, which was better other studies’ methods. secondly focused pollutants observed an increase Air Quality Index by 10%, decrease PM2.5 14%, PM10 18%, NO2 SO2 16% period. found O3 31% period significant (PM10 42%, 97%, 89%, 36%, CO 58%, 31%). Lastly, policies studied results showed that achieved Grade I standards after implemented. Although there were many severe effects pandemic human health global economy, lockdowns likely resulted advantages owing reduced pollution significantly improved ambient quality. Following government must take action address environmental problems contributed deteriorating

Language: Английский

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Observational study of microphysical and chemical characteristics of size-resolved fog in different regional backgrounds in China

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 950, P. 175329 - 175329

Published: Aug. 8, 2024

Language: Английский

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Effects of Aerosol Number Concentration and Updraft Velocity on Relative Dispersion during the Collision–Coalescence Growth Stage of Warm Clouds

Atmosphere, Journal Year: 2023, Volume and Issue: 14(5), P. 828 - 828

Published: May 4, 2023

Relative dispersion (ɛ) is a key expression used to parameterize various cloud processes in global circulation models (GCMs) and meteorological mesoscale models. Aerosols, updraft velocity (w), different growth stages of warm clouds are known affect relative dispersion. A two-dimensional detailed bin microphysical model investigate the combined impacts aerosol number concentration (Na) on collision–coalescence stage. In addition, causes potentially controlling changes ɛ with explored. There three main influence regimes: regime, joint regime. The cause variations found be regimes. vigorous due stronger w results shift droplet spectrum toward larger droplets, average radius increases, but spectral width less variable, so ε decreases. evaporation dragging effect large droplets widens spectrum, mainly by reducing (Nc) 4–30 μm, increases reduction w. strongest reduces Nc at all radii decreasing w, (CDNCS) narrows, which becomes formation mechanism positive correlation between Evaporation negative Nc, weak become under background high concentration. At low concentrations, strong leads ε, opposite effect.

Language: Английский

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Study on Risk Prediction Model of Expressway Agglomerate Fog-Related Accidents

Atmosphere, Journal Year: 2023, Volume and Issue: 14(6), P. 960 - 960

Published: May 31, 2023

Based on meteorological observations, traffic flow data and information of accidents caused by fog or agglomerate along the expressways in Jiangsu Province Anhui China from 2012 to 2021, key impact factors including conditions, road hidden dangers conditions are integrated establish prediction model for risk levels expressway fog-related accidents. This takes discrimination occurrence as starting term, determines hazard introducing probability value accident disaster-causing factor. On this basis, hourly location sections with a danger taken construct correction scheme levels, final predicted level is obtained. The results show that criteria factor classification threshold, 72.3% correspond medium above, 86.2% consistent defined based parametric indexes. For prediction, six out seven higher which can help provide support safety under severe weather conditions. Moreover, into account impacts environment, conducive further improving reliability assessment results.

Language: Английский

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