关键词: 土地利用/覆被, 时空变化特征, 青藏高原, 数据集评价, 归因分析

Abstract: The characteristics of land use change from 1992 to 2015 in the Qinghai-Tibet Plateau are analyzed by examining the spatial-temporal distribution and change rate of land use using the 300 m high-precision land use data (abbreviated as TPDC_LUCC) of Qinghai-Tibet Plateau Research Institute on the basis of evaluating the accuracy of public land use data set. The attribution of land use change is also analyzed based on climate data and social economic data. Results reveal that:1) Among the public datasets,the TPDC_LUCC dataset has the longest sequence and the highest accuracy,especially the classification accuracy of cultivated land,urban land and water bodies;the 300 m land use data (abbreviated as ESA_LUCC) of the European Space Agency has the highest classification accuracy for grassland and the worst for cultivated land;the 30 m land use data (abbreviated as CASearth_LUCC) of the Institute of Space Information Innovation,Chinese Academy of Sciences has a relatively accurate classification of glacier and urban land,yet with a large error of unused land. 2) Grassland is the most widely distributed in Qinghai-Tibet Plateau,with a multi-year average proportion reaching 70.02%,followed by unused land such as sandy land and bare land,accounting for 15.81%. Urban land expanded rapidly,with a growth rate of 2.34% from 1992 to 2005 and 4.69% from 2005 to 2015. From 1992 to 2015,9.14% of unused land on the Qinghai-Tibet Plateau was turned into grassland,3.27% of shrub and arable land into forest land,and 5.5% of glaciers into water. 3) From 1992 to 2018,the average temperature of the Qinghai-Tibet Plateau increased by 1.17 ℃,and the increase of precipitation and temperature was the main driving factor for the increase of grassland,shrub and forest land in the eastern region. The significant increase of temperature led to the melting of glaciers in the northwest,and urbanization resulted in the increase of urban land and the decrease of cultivated land. Implementing ecological protection policies has significantly promoted the restoration of grassland and forest land on the Qinghai-Tibet Plateau.

Key words: land use/cover change, spatiotemporal characteristics, Qinghai-Tibet Plateau, data set evaluation, factor analysis