环境一号卫星CCD相机水体信息采集特性分析

Analysis on Characteristics of the Water Information Collected by "HJ-1" Satellite Multispectral CCD Sensors

利用覆盖我国4大海区共88景图像数据,针对4波段CCD相机(HJ-1A/CCD1、HJ-1A/CCD2、HJ-1B/CCD1、HJ-1B/CCD2)在水体中的信息采集特性进行分析。结果表明:(1)HJ-1A和B星虽不是水色卫星,但其CCD相机在水体中依然有一定的信息,可作为水色遥感器服务于水环境;(2)HJ-1B/CCD1在南海海域水体信息采集过程存在明显的太阳耀斑现象,因而在水色信息提取时太阳耀斑是一个不可忽略的因子;(3)无论是在一类水体还是在二类水体,各遥感器的近红外波段皆存在水体信息采集为零的现象,其中HJ1B-CCD2尤为明显。利用近10景涵盖了HJ-1A/CCD1、HJ-1A/CCD2、HJ-1B/CCD1、HJ-1B/CCD2数据,以及同时过境的EOS/MODIS,采用基于遥感器入瞳处总辐亮度的交叉定标方法进行交叉辐射定标,获取适用于水体目标的交叉辐射定标参数。最后根据瑞利散射和气溶胶散射的计算值,以及获取的交叉定标系数,反推出HJ1B-CCD2可能接受到的灰度值。

The home-made satellites ＇HJ-1A＇ and ＇HJ-1B＇ were successfully launched in September 2008.Their role is to serve the country＇s disaster and environmental monitoring.The main sensors on the satellites are 4-band CCD cameras with a wide coverage,hyperspectral imager（HSI） and infrared cameras（IRS）.In this paper,the water information characteristics of the 4-band CCD cameras（HJ-1A/CCD1,HJ-1A/CCD2,HJ-1B/CCD1,HJ-1B/CCD2） were analyzed.The results showed that（1） although HJ-1A and B are not water color satellite,but each sensor still has some information about the water,so it can be used as water color remote sensors for water environment study;（2） for HJ-1B/CCD1 during water information collection in the South China Sea exists an obvious phenomenon of solar flares,so in the extraction of water color information that should not be ignored;（3） whether in case 1 or in case 2,this situation happens,the water body information of near-infrared bands of each sensor is zero,especially of HJ1B-CCD2.The four visible and near-infrared spectral bands of HJ-1/CCD1,HJ-1A/CCD2,HJ-1B/CCD1 and HJ-1B/CCD2 were calibrated respectively using cross-calibration methods based on the EOS/MODIS.The latter has the high radiation precision,and simultaneously passed through the South China Sea.The Radiometric Calibration coefficients of water-body targets of ＂HJ-1＂ satellite multispectral CCD sensors were obtained and validated.Finally,according to the calculation value of rayleigh scattering and aerosol scattering,HJ1B-CCD2 should be able to receive the gray value;this provides a reference to the sensor data application.