洞庭湖1996—2016年时空特征变化研究

Study on change of temporal and spatial characteristic of Dongting Lake from 1996 to 2016

以1996—2016年Landsat和高分1号影像为主要数据源,为了更快速且准确地从海量影像中提取水体信息,采用水体指数和阈值相结合的方法提取洞庭湖水面信息,取得很好的结果。同时,结合城陵矶站的水位数据,对洞庭湖湖区四季的时空特征、水面面积和水位之间的相关性及湖区面积时序变化特征进行定量分析。研究结果表明:1)洞庭湖水面面积季节性差异十分明显,夏季处于丰水期,表现为汪洋一片,平均湖面面积达到最大,春秋季节次之,冬季处于枯水期,平均湖面面积最小;2)水面面积和水位之间具有强烈的相关性,整体相关系数的平方达到0.948 2;3)水面面积整体有下降趋势,其中夏、秋季节下降趋势较明显,春、冬季节较不明显。

The Landsat and GF-1remote sensing images from1996to2016are used as the main data sources in the study.To extract water information more quickly and more accurately from the massive remote sensing images,a water data extracting method by combining water index and threshold is put forward in this paper,which turns out to be very effective.Meanwhile,combining with water level data of Chenglingji station,in order to quantitatively analyze the temporal and spatial characteristics of Dongting Lake,the correlation between lake area and water level and the characteristics of Dongting Lake area's seasonal change,the information about water surface and water level is used together.Listed below are the conclusions in this study:1)The area of Dongting Lake has seasonal differences.Summer is in the flood period,and the average lake area reaches to the largest.The lake area in spring and autumn is smaller than that in summer.Winter is in the dry season,and the average lake area reaches to the smallest.2)There is a strong correlation between lake area and water level,between which the square of correlation coefficient is0.9482.3)The lake area has been decreasing in recent years on the whole.And the downtrend in summer and autumn is more obvious than that in spring and winter.