环境一号卫星多光谱数据在巢湖蓝藻动态监测中的应用

Application of Environmental Satellite HJ1A /1B-CCD Data for Cyanobacteria Dynamic Monitoring in Chaohu Lake

采用环境一号卫星(HJ1A/1B)的多光谱(CCD)数据,通过影像预处理提取巢湖湖域蓝藻的归一化植被指数(NDVI),对巢湖湖域的蓝藻进行动态遥感监测,在GIS平台上计算蓝藻在研究时段内的平均空间分布、模拟其变化趋势及平均改善速度,结果表明,HJ1A/1B-CCD影像数据具有较高时空分辨率,对巢湖湖域蓝藻的识别能力强;巢湖湖域生态环境总体较好,蓝藻只是在局部湖域暴发,其中蓝藻极高密度区、高密度区呈团状、片状,主要集中分布在巢湖西湖区北部沿岸,并且为楔形向中心延伸;巢湖蓝藻暴发的湖域总体呈现改善趋势,但各区改善的程度、速度差异较大,原因复杂,尤其是西湖区北部沿岸不仅改善速度缓、改善程度不佳,甚至出现退化;巢湖西区应以治理为主、监测为重,东区则以着重监测。

It was Caculated that NDVI of Cyanobacteria in Chaohu Lake from HJ1AB-CCD data which had been Systematicly preprocessed（ radiation calibration and geometric correction included ） , and caculated the average spatial distribution which showed where was the most serious districts about Cyanobacteria outbreaking, modeled the change trends and the average improved speed of Cyanobacteria in ArcGIS in this study period stage, in order to Dynamicly monitor Cyanobacteria timly in area of Chaohu Lake. The final results shows that HJ1A/1B-CCD data has high spatial and temporal resolution and is more suitable for extraction of the breaking out area Cyanobacteria, overall this is key factor that our team chose that data. It is estimated that quality of water in Chaohu Lake is high in general, however, Cyanobacteria had been broken out in part of Chaohu lake, the districts of tip density and the region of high density were located in the appearance of banding in the northwest of Chaohu Lake and the zones of Cyanobacteria breaking out were wedging into the cennter of Chaohu Lake from the average spatial distribution of Cyanobacteria in Chaohu lake. Cyanobacteria outbreaking in most serious zone of Chaohu have being showed the trend of improved overall, yet the degree and speed of improvement was not alike in different areas of Chaohu Lake, and the reason of improvement was illustrated complex, Even more serious is that the degree and speed of making better about Cyanobacteria outbreaking in serious northwest zones of Chaohu Lake were slowness, worsestill a little of region in that critical zone was degenerating day by day. At last, west area of Chaohu Lake should better be mainly with improvement, meanwhile east area of Chaohu Lake should be focus on monitoring.