PARASOL(Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) multi-channel and multi-directional polarized data for different aerosol types were compared.The P...PARASOL(Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) multi-channel and multi-directional polarized data for different aerosol types were compared.The PARASOL polarized radiance data at 490 nm,670 nm,and 865 nm increased with aerosol optical thickness(AOT) for fine-mode aerosols;however,the polarized radiances at 490 nm and 670 nm decreased as AOT increased for coarse dust aerosols.Thus,the variation of the polarized radiance with AOT can be used to identify fine or coarse particle-dominated aerosols.Polarized radiances at three wavelengths for fine-and coarse-mode aerosols were analyzed and fitted by linear regression.The slope of the line for 670 nm and 490 nm wavelength pairs is less than 0.35 for dust aerosols.However,the value for fine-mode aerosols is greater than 0.60.The Support Vector Machine method(SVM) based on 12 vector features was used to discriminate clear sky,coarse dust aerosols,fine-mode aerosols,and cloud.Two cases were given and validated by AErosol RObotic NETwork(AERONET) measurements,MODIS(Moderate Resolution Imaging Spectroradiometer) FMF(Fine Mode Fraction at 550 nm) images,PARASOL RGB(Red Green Blue) images,and CALIOP(Cloud-Aerosol Lidar with Orthogonal Polarization) VFM(Vertical Feature Mask) data.展开更多
基金supported by the National Basic Research Program of China (Grant Nos.2010CB950804 and 2013CB955801)the Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues (Grant No.XDA05040202)
文摘PARASOL(Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) multi-channel and multi-directional polarized data for different aerosol types were compared.The PARASOL polarized radiance data at 490 nm,670 nm,and 865 nm increased with aerosol optical thickness(AOT) for fine-mode aerosols;however,the polarized radiances at 490 nm and 670 nm decreased as AOT increased for coarse dust aerosols.Thus,the variation of the polarized radiance with AOT can be used to identify fine or coarse particle-dominated aerosols.Polarized radiances at three wavelengths for fine-and coarse-mode aerosols were analyzed and fitted by linear regression.The slope of the line for 670 nm and 490 nm wavelength pairs is less than 0.35 for dust aerosols.However,the value for fine-mode aerosols is greater than 0.60.The Support Vector Machine method(SVM) based on 12 vector features was used to discriminate clear sky,coarse dust aerosols,fine-mode aerosols,and cloud.Two cases were given and validated by AErosol RObotic NETwork(AERONET) measurements,MODIS(Moderate Resolution Imaging Spectroradiometer) FMF(Fine Mode Fraction at 550 nm) images,PARASOL RGB(Red Green Blue) images,and CALIOP(Cloud-Aerosol Lidar with Orthogonal Polarization) VFM(Vertical Feature Mask) data.
