Research on Relationship Between Cyanobacteria Bloom and Water Temperature in Lake Taihu Based on MODIS Data

Spectral characteristic of all the cloudless 60 EOS-MODIS imageries during April and December in 2008 was analyzed in Lake Taihu,and the information of cyanobacteria bloom distribution and migration was extracted by the algorithm of Normalized Difference Vegetation Index (NDVI).In order to find out the temperature effect on cyanobacteria bloom temporal and spatial variation,the relationship between water temperature and cyanobacteria bloom was analyzed based on flock of data.On the basis of the synchronous water temperature data retrieved by split-window algorithm,the statistics showed that there was a close relationship between the acreage of cyanobacteria bloom and the average water surface temperature.When the water temperature was below 20℃,it had obvious correlation with cyanobacteria bloom growing or falling off.When the temperature ranged from 20℃ to 30℃,it would become an important environment factor and cyanobacteria bloom occurred with higher possibility.When the temperature was above 30℃,it might inhibit cyanobacteria bloom.The critical temperature of cyanobacteria bloom dying off was lower than its germination temperature.It was also found that the spatial difference of water temperature was one of the important factors which influenced the distribution and migration of cyanobacteria bloom in Lake Taihu.