Spatial and temporal distribution variation and meteorological factors analyzing of algal blooms based on HJ-1 satellites in Lake Dianchi, China, 2009

This paper described an approach used HJ-1 CCD data to monitor algal blooms in Lake Dianchi, China. After the radiometric calibration, atmospheric correction and geometric correction, HJ-1CCD reflectance data were obtained and NDVI threshold values were chosen to separate the bloom and nonbloom water. 148 HJ-1 CCD images were used in which 66 effective images were chosen to monitor algal blooms of Lake Dianchi. 39 times of algal blooms occurred in 2009 and only one time algal bloom area is greater than 15 square kilometers. The algal bloom annual frequency and bloom initial date were analyzed. The paper summarized that the bloom areas in Lake Dianchi are mainly located in northern lake and Caohai, the bloom began on March and ended on December, the most frequency bloom region is northern lake, and the most serious bloom month is September and October.