HJ-1A卫星CCD1数据的大气校正及在滇池蓝藻监测中的应用

HJ-1A卫星CCD1数据具有免费、高空间分辨率等优点,但是由于受大气的影响,电磁波在传输过程中发生失真。为了提高CCD1数据的提取精度,就必须对其进行大气校正。本文利用6S模型对2013年9月30日的HJ-1A卫星CCD1数据进行了大气校正,并从归一化植被指数(NDVI)的变化、与中分辨率成像光谱仪(MODIS)地表反射率数据对比2个方面对校正结果进行精度验证。结果表明:NDVI的标准差校正前为0.179866,校正后为0.247689,大气校正能够有效地降低大气对遥感图像造成的影响,图像的层次更加丰富;在滇池的建筑物、水体、植被3种地物中分别选取1个像元,获得CCD1数据和MODIS数据分别在这3个像元上的反射率值。3种地物的地表反射率在2种数据中都具有较好的一致性,在4个波段的误差均在15%左右。对于水体,波段3和波段4的误差较小(10%),建议在进行滇池水质参数反演时尽量选用3、4波段。利用经过大气校正后的CCD1数据计算NDVI并结合密度分割的方法对滇池蓝藻信息进行了提取,提取的结果与滇池蓝藻实测数据具有较好的相关性,相关系数达到0.7703,说明利用HJ-1A卫星CCD1数据可以快速、动态地监测滇池蓝藻暴发。

Atmospheric Correction of HJ-1ACCD1 Data and Its Application in Cyanobacteria Bloom Monitoring in Dian Chi Lake

HJ-1ACCD1 is suitable to monitor cyanobacteria bloom for its free and high spatial resolution.However, due to the influence of the atmosphere ,electromagnetic do not directly characterize the surface objects.Atmospheric correction is necessary to improve the Extraction accuracy of CCD1.In this paper,6S model is used to atmospheric correction of HJ-1ACCD1,then,the accuracy of atmospheric correction on HJ-1ACCD1 is analyzed in The different NDVI ,and comparison with MODIS surface reflectance products.The results showed that: atmospheric correction can effectively reduce the impact of Atmosphere on remote sensing image, after atmospheric correction, NDVI standard deviation increase and the level of the image is richer.Finally,Dian Chi cyanobacteria information is extracted by combining NDVI and density segmentation,the results extracted and Cyanobacteria measured data of Dianchi have good releative.this results show:use HJ-1ACCD1 data can quickly and dynamically monitor Cyanobacterial blooms.