| 引用本文: | 李国砚,张仲元,郑艳芬,刘晓玫.MODIS影像的大气校正及在太湖蓝藻监测中的应用.湖泊科学,2008,20(2):160-166. DOI:10.18307/2008.0204 |
| LI Guoyan,ZHANG Zhongyuan,ZHENG Yanfen,LIU Xiaomei.Atmospheric correction of MODIS and its application in cyanobacteria bloom monitoring in Lake Taihu. J. Lake Sci.2008,20(2):160-166. DOI:10.18307/2008.0204 |
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| 摘要: |
| MODIS数据有免费、波段丰富、时间分辨率高等优点,是进行太湖蓝藻监测的重要数据源,由于MODIS传感器接收的是地物反射太阳辐射的信号,太阳辐射与地球大气的相互作用会引起传感器接收到的信号失真,为了提高利用MODIS数据监测太湖蓝藻的精度,必须对其进行大气校正.本文介绍了FIAASH大气校正模型的基本原理,并对2007年4月25日MODIS数据的前七个波段进行试验,对比分析了影像大气校正前后的NDVI值以检测大气校正的效果;分析表明,大气校正前后NDVI的变化趋势基本上相同,但大气校正后的NDVI动态范围更大,校正后NDVI的平均值和标准差增大,大气校正在一定程度上有效地降低了大气对遥感影像的影响,达到了增强信息的目的:最后,利用大气校正获取的地表真实反射率数据的第二波段与第一波段的比值,运用阈值法提取蓝藻信息,经试验当阈值为1.9时提取出来的蓝藻分布图基本上与实际相符.利用MODIS影像可以快速、及时地监测蓝藻爆发的位置及爆发程度. |
| 关键词: MODIS 大气校正 FLAASH 蓝藻 |
| DOI：10.18307/2008.0204 |
| 分类号: |
| 基金项目:中国科学院“优秀博士论文、院长奖获得者科研启动专项资金”;国家自然科学基金(2007BAC26B01);江苏省自然科学基金(BK2007261)联合资助 |
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| Atmospheric correction of MODIS and its application in cyanobacteria bloom monitoring in Lake Taihu |
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LI Guoyan1,2, ZHANG Zhongyuan3, ZHENG Yanfen4, LIU Xiaomei1
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1.Nanjing Institute of Geography & Limnology, CAS, Nanjing 210008, PR. China;2.Graduate School, Chinese Academy of Sciences, Beijing 100049, PR. China;3.College of Environment and Planing, Henan University, Kaifeng 475004, P R. China;4.Environment Management College of China, Qinhuangdao 066004, PR. China
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| Abstract: |
| MODIS, a good remote sensing image data source, is suitable to monitor cyanobacteria bloom for its free and high timeresolution, however, MODIS sensor receives distorting signals, due to the interaction between solar radiation and atmosphere, andatmospheric correction is necessary to acquire true surface reflectance and improve the accuracy of monitoring cyanobacteria bloom.In this paper, the basic theory of FLAASH atmosphere correction model attached in ENVI software, which derives from theMODTRAN 4 radiative transfer code, was introduced and explained. Then the FLAASH code was used to process MODIS data, andthe NDVI after atmospheric correction was compared with that before correction. Results indicated that atmosphere's influences werereduced and useful information was enhanced. In the end, the ratio between Band2 and Band1 which was obtained by FLAASHatmospheric correction, was used to extract the cyanobacteria bloom information with the threshold. |
| Key words: MODIS atmospheric correction FLAASH cyanobacteria bloom |
