scholarly journals Spatial and Temporal Variations of Aerosol Optical Thickness over the China Seas from Himawari-8

2021 ◽  
Vol 13 (24) ◽  
pp. 5082
Author(s):  
Qianguang Tu ◽  
Yun Zhao ◽  
Jing Guo ◽  
Chunmei Cheng ◽  
Liangliang Shi ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Temporal Variations ◽  
Diurnal Variations ◽  
Aerosol Optical Thickness ◽  
Spatial And Temporal Variations ◽  
China Seas ◽  
Monthly Variation ◽  
Low Latitude ◽  
Spatial Feature ◽  
The China Seas

Six years of hourly aerosol optical thickness (AOT) data retrieved from Himawari-8 were used to investigate the spatial and temporal variations, especially diurnal variations, of aerosols over the China Seas. First, the Himawari-8 AOT data were consistent with the AERONET measurements over most of the China Seas, except for some coastal regions. The spatial feature showed that AOT over high latitude seas was generally larger than over low latitude seas, and it is distributed in strips along the coastline and decreases gradually with increasing distance from the coastline. AOT undergoes diurnal variation as it decreases from 9:00 a.m. local time, reaching a minimum at noon, and then begins to increase in the afternoon. The percentage daily departure of AOT over the East China Seas generally ranged ±20%, increasing sharply in the afternoon; however, over the northern part of the South China Sea, daily departure reached a maximum of >40% at 4:00 p.m. The monthly variation in AOT showed a pronounced annual cycle. Seasonal variations of the spatial pattern showed that the largest AOT was usually observed in spring and varies in other seasons for different seas.

scholarly journals Spatial and temporal variations of atmospheric aerosol optical thickness in northwestern Mexico

2013 ◽  
Vol 52 (4) ◽  
pp. 321-341 ◽  
Author(s):  
Ricardo M. Llamas ◽  
Roberto Bonifaz ◽  
Mauro Valdés ◽  
David Riveros-Rosas ◽  
Amando LeyvaContreras
Keyword(s):  
Optical Thickness ◽  
Atmospheric Aerosol ◽  
Temporal Variations ◽  
Aerosol Optical Thickness ◽  
Spatial And Temporal Variations ◽  
Northwestern Mexico

scholarly journals Seasonal distribution of aerosol properties over Europe and their impact on UV irradiance

2009 ◽  
Vol 2 (4) ◽  
pp. 1863-1899
Author(s):  
N. Y. Chubarova
Keyword(s):  
Optical Thickness ◽  
Spectral Region ◽  
Single Scattering ◽  
Temporal Variations ◽  
Aerosol Optical Thickness ◽  
Asymmetry Factor ◽  
Uv Irradiance ◽  
Aerosol Parameters ◽  
Radiative Transfer Modeling

Abstract. Using the aerosol optical thickness at 550 nm (τ550) from MODIS (collection 5) combined with the aerosol products from the ground-based AERONET network, key aerosol parameters have been obtained with 1 degree resolution over Europe. Additional tests have revealed a satisfactory quality of the MODIS data, except in a few cases. Quality assured AERONET data are used for evaluating the Angstrom exponent, single scattering albedo and asymmetry factor, and for validating the final aerosol optical thickness in the UV spectral region. A method for extrapolating the aerosol parameters into the UV spectral region is discussed. The aerosol optical thickness distributions are considered together with meteorological fields from NOAA_NCEP_CPC_CAMS_OPI climatology. The τ340 is shown to vary significantly from approximately 0.01 to 0.9 depending on the season and location. Permanent elevated aerosol loading over several industrial areas is observed, which agrees with the output of chemical transport models. Using radiative transfer modeling, monthly mean UV loss due to aerosol was estimated. The absolute decrease in UV indices varies from less than 0.1 to 1.5. The relative UV attenuation has large spatial and temporal variations (from −1% to −17%) with a minimum towards the northwest and maxima over several southern local areas (Northern Italy, etc.) during the warm period.

scholarly journals Observation of rapid aerosol deposition according to AERONET data

2019 ◽  
Vol 99 ◽  
pp. 03006
Author(s):  
Vladimir Maslov ◽  
Sabur Abdullaev ◽  
Bahron Nazarov
Keyword(s):  
Water Vapor ◽  
Optical Thickness ◽  
Diffusion Coefficients ◽  
Double Diffusion ◽  
Aerosol Deposition ◽  
Diurnal Variations ◽  
Aerosol Optical Thickness ◽  
Concentration Increase ◽  
Coagulation Of Particles ◽  
The Difference

Measurements at the AERONET station in Dushanbe showed that the diurnal variations of the aerosol optical thickness (AOT), humidity, Ångström parameter depend on the stratification of the atmosphere. It is established that the dynamics of the aerosol in the ground inversion temperature layer is determined by the effect of double diffusion, which is manifested as a result of the difference in the diffusion coefficients of the components. As the temperature and aerosol concentration increase from the bottom to the top, vertical convection cells of the "salt finger" type are formed, which cause a rapid settling of dust by means of condensation of water vapor and coagulation of particles and water droplets.

scholarly journals Seasonal distribution of aerosol properties over Europe and their impact on UV irradiance

2009 ◽  
Vol 2 (2) ◽  
pp. 593-608 ◽  
Author(s):  
N. Y. Chubarova
Keyword(s):  
Optical Thickness ◽  
Spectral Region ◽  
Single Scattering ◽  
Temporal Variations ◽  
Aerosol Optical Thickness ◽  
Asymmetry Factor ◽  
Mean Values ◽  
Uv Irradiance ◽  
Aerosol Parameters

Abstract. Using the aerosol optical thickness at 550 nm (τ550) from MODIS (collection 5) for the 2000–2008 period combined with the aerosol products from the ground-based AERONET network since 1996, monthly mean values of key aerosol parameters have been obtained with 1 degree resolution over Europe. Additional tests have revealed a satisfactory quality of the MODIS data, except in a few cases. Quality assured AERONET data are used for evaluating the Angstrom exponent, single scattering albedo and asymmetry factor, and for validating the final aerosol optical thickness in the UV spectral region. A method for extrapolating the aerosol parameters into the UV spectral region is discussed. The aerosol optical thickness distributions are considered together with meteorological fields from NOAA_NCEP_CPC_CAMS_ OPI climatology. The τ340 is shown to vary significantly from approximately 0.01 to 0.9 depending on the season and location. Permanent elevated aerosol loading over several industrial areas is observed, which agrees with the output of chemical transport models. Using radiative transfer modeling, monthly mean UV loss due to aerosol was estimated. The absolute decrease in UV indices varies from less than 0.1 to 1.5. The relative UV attenuation has large spatial and temporal variations (−1%–−17%) with a minimum towards the northwest and maxima over several southern local areas (Northern Italy, etc.) during the warm period.

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