应用MODIS监测太湖蓝藻水华时空分布特征

DETERMINATION OF SPATIAL AND TEMPORAL DISTRIBUTION OF CYANOBACTERIAL WATER BLOOM IN TAIHU LAKE USING MODIS IMAGE DATA

利用波段比值算法对经几何校正和大气矫正后的MODIS/Terra L-1B数据进行处理,获取了2004～2010年天气晴好条件下太湖及各分湖区蓝藻水华的面积与时空分布,并在此基础上对太湖蓝藻水华的时空变化特征进行了分析。结果表明:2004～2010年太湖地区共暴发蓝藻水华539次;2004～2007年太湖蓝藻水华首次暴发时间逐年提前,暴发频次逐年增加,2007～2010年太湖蓝藻水华首次暴发时间逐年推迟,暴发频次逐年减少;2004～2010年3～8月份蓝藻水华暴发次数有增加的趋势,8～12月份蓝藻水华暴发次数有减小的趋势;2004～2010年太湖蓝藻水华主要发生在北部和西部湖区,东部和南部湖区发生次数较少,各分湖区蓝藻水华暴发概率大小的顺序为:西部沿岸>大太湖>梅梁湾>南部沿岸>竺山湖>贡湖。

Based on multi-temporal MODIS image data processed by band ratio algorithm,we extracted the distribution of cyanobacteria bloom in Taihu Lake during the period of 2004~2010 in sunny days and analyzed its spatiotemporal variation.Results showed that during 2004~2010,cyanobacteria bloom in Taihu Lake area happened 539 times totally.During 2004~2007 the initial time of cyanobacteria bloom was advanced and its frequency increased year by year,while during 2007~2010 the time was put off and its frequency decreased.The cyanobacteria bloom occurred more frequently between March and August while less frequently between August and December in each year.Spatial analysis results of 2004~2010 showed that the cyanobacteria bloom happened much more frequently in the northern and western lake areas than in the eastern and southern lake areas.The frequency of bloom happened in each lake areas can be ordered as：western offshore〉main body of Taihu Lake〉Meiliang Bay〉Southern riverside areaZhushan lake〉Gonghu Lake.