太湖秋冬季蓝藻水华MODIS卫星遥感监测

Monitoring Cyanobacterial Blooms Using MODIS Images in Taihu Lake,China

利用2007年10-12月长时间序列MODIS卫星遥感影像，在经验模型估算叶绿素a和藻蓝素浓度的基础上，通过阈值分割提取太湖蓝藻水华，实时获取了蓝藻水华及其色素浓度信息。结果表明：10～12月蓝藻主要分布在西部沿岸和湖心区，爆发频率和水华面积均高于北部各湖湾，其中10、11月平均水华面积分别为261．5km^2和321．6km^2，12风水华面积明显小于前两个月，平均为163．3km^2。另外，在蓝藻爆发期，叶绿素a和藻蓝素平均含量基本维持在45μg／L和180μg／L的水平，且爆发期内，蓝藻水华的空间分布、覆盖面积、色素浓度在短时间内会发生非常大的变化。

Using a series of MODIS satellite images from October to December in 2007, this study adopts empirical model to estimate chlorophyll-a and phycocyanin concentration and retrieves the cyanobacteria blooms information based on threshold values. Results show the blooms occurred frequently in the west bank and the center of the lake, where the frequency and covering area were higher than those in the north bays, during October, November and December, 2007. The average covering area of cyanobacterial blooms in the three months is 261.5km^2, 321.6 km^2 and 163.3 km^2 , respectively. Therefore, the blooms were marked smaller in December than in October and November. During bloom period, the average chlorophyll-a and phycoeyanin concentrations are about 45μg/L and 180μg/L, respectively. The spatial distribution, covering area, and pigment concentration changed quickly in short time in bloom period.