洞庭湖区地表温度反演及其时空变化特征

洞庭湖是我国第二大的淡水湖，对区域气候的调节起着极其关键的作用，然而受全球变暖及其他因素的影响，洞庭湖区范围内对气候变化的响应并不一致。为了更好地认识洞庭湖区的地表温度变化及其对全球变暖的响应情况，同时为准确的判断该区温度未来的变化趋势奠定基础，利用1995年、2004年和2013年12景冬季Landsat TM/ETM＋遥感影像的热红外波段数据反演了洞庭湖区地表温度，并对反演的地表温度值进行标准化处理，采用标准差分类法得到地表温度等级图。通过三时相温度等级图的面积统计与直观对比，分析了洞庭湖区在三峡蓄水前后的温度时空变化特征；并结合归一化植被指数（NDVI）、降雨资料、DEM、坡度等数据对洞庭湖区的温度变化影响因素进行了统计分析。结果表明，（1）洞庭湖区各温度等级面积成正态分布，主要以中温区、较高温区和较低温区为主。从空间分布上来看，低温区主要分布在水体，而高温区则没有明显的分布特征。（2）受雨雪天气影响，2004年的高温范围减少，减少情况为西洞庭湖区〉南洞庭湖区〉东洞庭湖区，面积变化比例分别是5.38%、2.12%、0.71%，表明冷气流对西洞庭湖区的温度变化影响最强，而东洞庭湖区最弱。（3）2013年高温范围增加，且变化强度呈现出西洞庭湖区〈南洞庭湖区〈东洞庭湖区的空间特征，面积变化比例分别是2.21%、2.38%、2.68%，表明在三峡水库蓄水之后，东洞庭湖区的地表温度受到较大影响。（4）植被的覆盖情况与温度相关性不明显，而坡度、海拔与温度呈正相关关系，这表明坡度可以有效的减少冷气流对温度的影响，地势较高地区与阳坡出现高温情况则表明地表温度受太阳辐射影响较大。

Temporal and Spatial Variation Characteristics of Land Surface Temperature in Dongting Lake Region,Hunan Province

As the second largest fresh lake in China, Dongting Lake plays a significant role in regulating regional climate. However, due to global warming and other factors, its responses to climate change are not consistent within the Dongting area. For a better understanding of the land surface temperature （LST） change of the Dongting Lake area and its responses to global warming, and also for a better prediction of the LST variation trend, the LST of Dongting Lake area was retrieved using wintertime data of the 12 Landsat TM/ETM＋ thermal infrared band images in 1995, 2004 and 2013. The standardized processing of retrieved LST was conducted and the LST grade maps were developed through standardized deviation classification. The LST temporal and spatial variation characteristic was analyzed through area statistic and straight comparison of the three LST grade maps. And the influential factors of LST variation were analyzed through normalized difference vegetation index （NDVI）, rainfall data, DEM, gradient and other relevant data. The result shows that： （1） The area of each LST grade in Dongting Lake is of the normal distribution, and it mainly consists of middle temperature area, higher temperature area and lower temperature area. In terms of spatial distribution, the lower temperature area is mainly in water, and there is no distinct distribution characteristic in higher temperature area;（2）Impacted by the rain and snow, the range of high temperature area decreases in 2004.The proportion of decreased area from large to small in turn is West Dongting Lake（5.38%） to South Dongting Lake（2.12%） to East Dongting Lake（0.71%）, suggesting that the cold air flow influences the West Dongting Lake the most, the East the least; （3）The range of high temperature area increases in 2013, and the proportion of increased area from small to large is West Dongting Lake（2.21%） to South Dongting Lake（2.38%） to East Dongting Lake（2.68%）, suggesting that the LST of East Dongting Lake is greatly af