滇池蓝藻水华光谱特征、遥感识别及暴发气象条件  

Spectral features,remote sensing identification and breaking-out meteorological conditions of algal bloom in Lake Dianchi

作　　者：谢国清[1] 李蒙[1] 鲁韦坤[1] 周伟民[1] 余凌翔[1] 李发荣[2] 杨树平[2] 

机构地区：[1]云南省农业气象与卫星遥感应用中心,昆明650034 [2]昆明市环境监测中心,昆明650034

出　　处：《湖泊科学》2010年第3期327-336,共10页Journal of Lake Sciences

基　　金：中国气象局蓝藻水体监测预警系统(一期)项目;昆明市环境保护局项目联合资助

摘　　要：通过研究滇池蓝藻水华在可见光、红外谱段的光谱特征,并利用假彩色合成法以及归一化植被指数(NDVI)法进行了滇池蓝藻水华信息的遥感识别和提取,进而对提取结果进行了对比分析.结果表明:假彩色合成图的绿色区域和NDVI值大于-0.1的区域,为蓝藻水华区域.-0.1≤NDVI≤0.2时,轻度水华,像元内水华覆盖度为0-30%;0.2<NDVI≤0.4时,中度水华,像元内蓝藻水华覆盖度为31%-80%;NDVI>0.4时,重度水华,水华浓厚,像元内蓝藻水华覆盖度为81%-100%.同时研究了激励滇池蓝藻水华暴发的关键气象因子和指标.滇池蓝藻水华暴发的关键时期是6-9月份,影响滇池蓝藻暴发的关键因子是日照和风速.6-9月份连续4-5h的光照,且风速≤2m/s的气象条件组合极易引起蓝藻水华暴发.Based on high spectral reflectivity features of Blue-green Algal Bloom （BAB） in Lake Dianchi, by MODIS satellite remote sensing data, RGB ：621 combined false color synthesis and Normalized Difference Vegetation Index（NDV1）method, we found that green region in false color synthesis image and the region with NDVI value 〉 -0.1 were just the BAB area. When -0.1≤ NDVI≤0. 2, slight BAB occurred, and bloom coverage in a pixel reaches 0 -30%; when0. 2 〈 NDVI≤0. 4, moderate bloom happened, bloom coverage in a pixel reached 31%- 80%; dense bloom comed forth while NDVI 〉 0.4, and bloom coverage in a pixel can be 81% - 100%. From June to September is the key period for BAB breaking-out in Lake Dianchi, and the key factors to affect BAB breaking-out maybe sunshine and wind velocity. During this period, if the sunshine can last for only 4 -5 hours and the wind velocity ≤2m/s, it＇s quite easy for BAB breaking-out.

关 键 词：MODIS 蓝藻水华 遥感识别 气象条件 滇池 

分 类 号：X87[环境科学与工程—环境工程] P237[天文地球—摄影测量与遥感]