科尔沁沙地沙丘-草甸相间地区1986-2013年湖泊演变

湖泊变化敏感地记录着气候变化的信息。以科尔沁沙地沙丘-草甸相间地区为研究区,利用多时相TM/ETM+遥感影像,基于遥感和GIS技术提取研究区1986-2013年湖泊个数与面积信息,分析其变化规律及空间分异特征。在此基础上,联系降水量、蒸发量等气候要素和以人类活动影响为主的时间因子t,采用多元统计分析方法对研究区湖泊面积进行了模拟分析。结果表明:(1)研究区小型湖泊近30年间面积和个数均发生了不同程度的变化,其变化趋势与降水量呈现很强的正相关,与蒸发量呈较强的负相关,人类活动对小型湖泊面积的影响不太显著,随着时间的推移,研究区湖泊面积趋于萎缩,这种萎缩主要归因于气候的干化;(2)研究区t年湖泊面积A_t与前一年湖泊面积A_t-1、t年降水量P_t和蒸发量E_t存在较强的相关关系;(3)1986-2013年研究区典型湖泊--王巴哈嘎湖泊总体上呈萎缩状态,但不同方向上既有萎缩也有扩张,Ⅰ、Ⅱ、Ⅴ、Ⅵ区域(以北向为0°,顺时针每45°一个区域,并顺序标记为Ⅰ~Ⅷ区域)萎缩,其他区域扩张,其中以Ⅱ、Ⅲ、Ⅷ、Ⅳ区域为主导变异方向,Ⅵ方向次之,其他方向变化缓滞。研究成果不仅为科尔沁沙地生态系统的健康维持提供技术支撑,对其他同类地区湖泊环境的研究也具有指导作用。

Lake Evolution and Effect Analysis of Meadow-dunes Area in the Horqin Sandy Land in 1986-2013

Lake changes sensitively recorded the messages of climate change. The Horqin typical sandy meadow area is chosen as the study area. The lake area information from 1986 to 2013 were extracted to analyze the variation law and spatial distribution characteristics using the multi temporal TM/ETM+ remote sensing images, based on remote sensing and GIS technology. The simulation and analysis of the lake area were performed using multivariate statistical analysis method combining with factors of precipitation, evaporation and the human activity effect time factor t. The results showed that: ①The numbers and area of lake in the study area have changed (increased or decreased) in the last 30 years, and the trends showed a strong positive correlation with the rainfall, while showed a negative correlation with evaporation, the influence of human activities to the small lake area was not significant, the lake area tended to shrink as time goes by, which was mainly attributed to the drying climate;②The lakes area in the year of t showed a strong correlation with the lake area of previous year, precipitation, and evaporation in the year of t, which can be simulated with the linear equations and nonlinear equations; ③the typical research area-the Wang Bahaga Lake, showed to be decreased during 1986-2013, but there were both atrophied and expanded in different directions: the I, II, V, VI region atrophied, while other regions expanded, the II, III, IV, VIII were dominant mutation direction, followed by the direction of VI, the other direction changed slowly. The region was marked as Ⅰ-Ⅷ by dividing the lake with every 45°, starting from north, clockwise. The results not only provided the technical support for the healthy maintain of Horqin sandy land ecosystem, but also could be a guidance for other similar lake areas.