联合历史地图与遥感技术的洞庭湖百年萎缩监测

Monitoring of Dongting Lake atrophy in the past 100 years by combining historical map and remote sensing technology

为了研究洞庭湖百年以来的萎缩情况,基于湖南省图书馆珍藏的清光绪22年(公元1896年)成图的《洞庭湖全图》等历史地图、1954年获取的航空像片、1967年美国KH-8军事卫星获取的影像及各类卫星遥感数据,对洞庭湖的百年变化情况进行了较系统的监测。监测结果表明:1896―2014年118 a期间,洞庭湖面积从5 146.71 km2萎缩到2 680.29 km2,减少了2 466.42 km2,为1896年湖盆面积的47.92%。监测结果与水利部门发布的洞庭湖面积变化数据非常接近。1998年长江发生特大洪涝灾害后,国务院明确"退田还湖"的治湖对策,使洞庭湖面积得以稳定。洞庭湖主要由人工修筑的防洪大堤围限,使来水来沙的变化不能改变防洪大堤的位置,因此,2003年三峡工程的运行没有影响洞庭湖的面积。

In order to study the atrophy of the Dongting Lake in the past 100 years, the authors systematically monitored the atrophy of the Dongting Lake based on historical topographic map data, such as the Dongting Lake map in the late Qing Dynasty （AD 1896） which is treasured by the Library of Hunan Province nowadays, aviation photos since 1954, satellite images which were captured by the American KH - 8 military satellite in 1967 and other aerospace remote sensing data. The results show that in the past 118 years from 1896 to 2014, the Dongting Lake area has shrunk by 2 466.42 km^2, from 5 146.71 km^2 to 2 680.29 km^2. Now the Dongting Lake area is 47.92% of the lake basin area in 1896. A comparison with the area variation data of the Dongting Lake published by the Water Conservancy Department shows the data obtained by two sources are generally-very close, with some differences in some specific areas. After the severe flooding disaster of the Yangtze River in 1998, the State Council explicitly put forward the lake - management policy of ＂Farmland Conversion to Lake Wetland＂ so as to stabilize the area of the Dongting Lake. The Dongting Lake is mainly enclosed by artificial levee whose location is irrelevant with sources of water and sands ; thus, the operation of ＂the Three Gorges＂ since 2003 has had no influence on the area of the Dongting Lake.