基于SPOT-VGT数据的洞庭湖水体面积变化分析

监测洞庭湖水体变化、全面了解其变化规律和演化趋势对于湖区治理和防洪减灾具有重要的现实意义.本文基于SPOT-VGT NDVI数据,采用动态阈值法提取了洞庭湖1998-2010年间逐旬水体信息,并结合历史数据分析了水体面积变化特征.主要结论如下:①动态阈值方法在长时间序列、大数据量的遥感信息提取中具有显著优越性.②洞庭湖水体面积在年内呈现明显季节性变化；在年际呈缩减趋势(丰水期)；1825-2010年水体缩减呈现四个阶段,当前处于新一轮的锐减期.③基于累积降雨量数据建立的水面积预测经验模型,精度较为理想.

Analysis of the variation of water area in Dongting lake based on SPOT-VGT data

Monitoring the changes of Dongting Lake water,as well as making a comprehensive understanding of the evolution rule has important practical significance for the lake district management,flood control and disaster alleviation.Based on SPOT-VGT NDVI data,adopting dynamic threshold method,this paper extracted every ten-day’s water information from 1998 to 2010.Combined with historical data,the analysis on the variation characteristics of water area was done.Main conclusions are as follows: ①For long time series and large amount of remote sensing data,the dynamic threshold method shows significant advantages in information extraction.②The water area in Dongting Lake presents obvious seasonal change in years and a interannual reduced trend(in rain season).From 1825 to 2010,the water reduction could be divided into four stages,and currently Dongting Lake is in a new round of sharply shrinking period.③The water area prediction model that is established based on cumulative rainfall data gives satisfactory prediction accuracy.