CALIOP反演海洋颗粒物后向散射方法

Methods of Ocean Subsurface Particulate Backscattering Coefficient Retrieval from CALIOP Measurements

云和气溶胶探测激光雷达(Cloud-aerosol lidar with orthogonal polarization,CALIOP)能够发射532 nm和1064 nm两种波长激光脉冲,主要用于大气中云和气溶胶的探测.532 nm激光脉冲在海洋表面有很好的穿透性,能获得海表以下的后向散射信号.利用CALIOP数据对直接提取水下信号和瞬态响应校正提取水下信号两种方法进行对比研究.首先,反演得到海洋次表层水下信号,进而反演海洋颗粒物后向散射,并与中分辨率成像光谱仪(Moderate-resolution imaging spectroradiometer,MODIS)反演的颗粒物后向散射进行对比.颗粒物后向散射差值的均值分别为0.0035、0.0027;标准偏差分别为0.4004、0.0042.表明校正方法反演的颗粒物后向散射与MODIS反演颗粒物后向散射更为接近.

Cloud-aerosol lidar with orthogonal polarization(CALIOP)can emit 532 nm and 1064 nm laser pulses which is mainly used for the detection of clouds and aerosols in the atmosphere.The 532 nm laser pulse can be used to get backscatter signal below the sea surface due to a good penetrability to the ocean surface.Based on the CALIOP data,the directly extracted signal and the corrected transient response signal of subsurface are studied.Firstly,the subsurface backscatters are calculated.Then thg marine particulate backscattering coefficients are retrieved from two different methods,and compared to particulate backscattering coefficients from moderate-resolution imaging spectroradiometer(MODIS)products.The mean of difference value of particulate backscattering coefficients are 0.0035 and 0.0027,and the standard deviation are 0.4004 and 0.0042 respectively,which indicates that particulate backscattering coefficients derived by using transient response correction method is closer to MODIS products.