新疆焉耆盆地地表温度时空分布对LUCC的响应

为了辨析地表温度时空分布及其变化对土地利用/土地覆盖变化(land use/cover change,LUCC)的响应,以新疆焉耆盆地为研究区,将Landsat遥感影像数据、气象要素的观测数据和野外采样数据相结合,利用单窗算法和单通道算法反演研究区2000、2009、2011和2015年的地表温度,分析焉耆盆地地表温度时空分布特征,研究LUCC对地表温度的影响。结果表明:1)研究区温度时空分布图主要划分为低温区、中温区和高温区。从时空分布变化上来看,2000年高温区范围减少幅度最大、2009年次之、2015年最小;2009年低温区范围减少幅度最大、2000年次之、2015年最小;2)研究区地表温度的分布具有明显的空间差异性,高温区主要分布在沙漠区和山区与盆地之间的戈壁滩,具有明显的以博斯腾湖为中心的环状分布特点。低温区主要分布在水域、湿地和绿洲等区域;3)在2011年内不同时期不同LUCC的温度变化幅度不一,地表温度在不同下垫面上平均值大小不同,地表温度高低主要表现为沙漠盐碱地裸地小麦-玉米其他作物森林棉花芦苇湿地水域。由结果可知,焉耆盆地近十几年地表温度的时空变化与LUCC有着密切关系,农作物的结构、土地利用类型及其面积变化都会影响地表温度的时空分布。

Spatiotemporal response of land surface temperature to land use/cover change in Yanqi Basin, Xinjiang

Abstract: Land-use/land cover change (LUCC) at local, regional, and global scales is one of the fundamental causes of environmental change. LUCC has been of great concern because innumerable consequent changes were produced on the earth surface. Some important researches showed that human-induced LUCC was one of the key factors which influence the regional climate. Rapid population growth and continuous exploitation of natural resources during the past century have caused rapid changes of land-use/cover. This trend has produced a series of environmental impacts on biodiversity, local climate, hydrologic processes, and so forth. The land surface temperature (LST) is the radiative skin temperature of ground. It depends on the albedo, the vegetation cover and the soil moisture. In most cases, LST is a mixture of vegetation and bare soil temperatures. In turn, the LST influences the partition of energy between ground and vegetation, and determines the surface air temperature. In recent decades, geographical information systems and remote sensing techniques are widely employed to investigate the impact of land-use/cover change on land surface temperature. Understanding the interconnection of biological and climatic processes is essential for predicting the effects of climate change on the biosphere. Spatiotemporal distribution of LST is a critical factor of environmental change, and is the driving forces of the land surface processes. Study on the spatiotemporal response of LST to LUCC is an important scientific issue under the circumstances of anthropogenic pressure increasing rapidly. In the paper, characteristics of spatiotemporal distribution of LST and its response to LUCC are studied by LST data retrieved by methods of mono-window algorithm and single-channel from Landsat data of the year 2000, 2009, 2011 and 2015, observed metrological data and field sampling data in Yanqi Basin, Xinjiang, China. Results demonstrated that: 1) LST was classified as high LST, medium LST and low LST. The decreasing ratio of high LST area from the greatest to the least took place in the year of 2000, 2009 and 2015, respectively; the decreasing ratio of low LST area from the greatest to the least took place in the year of 2009, 2000 and 2015, respectively; 2) the distribution of LST had different spatial patters obviously. High LST distributed in deserts and Gobi between mountain and basin, and it had a circular pattern around the Bosten Lake. Low LST distributed in water, wetlands and oasis area; 3) the amplitude of LST change was different depending on LUCC in 2011. The ranks of different land cover types were: desert>saline area>bare land>wheat-corn>other crops>forest>cotton>reeds wetland> waters. To sum, the spatiotemporal distribution of LST is closely related to LUCC. The structure of crop planting and the area of land use type are effecting the spatiotemporal distribution of LST in recent decades in the Yanqi Basin, Xinjiang.