2000-2018年锡林郭勒地区干旱时空变化及其气候响应

Temporal and spatial variations of drought and climatic response in the Xilingol grassland from 2000 to 2018

温度植被干旱指数(Temperature Vegetation Dryness Index,TVDI)是一种反映干旱状况的重要方法。以内蒙古自治区锡林郭勒为研究区,基于温度植被干旱指数,采用趋势分析、R/S分析方法,探究了锡林郭勒地区2000-2018年温度植被干旱指数TVDI时空变化特征及其降水、气温气候因子对TVDI变化的影响关系。研究表明:(1)19 a间,TVDI的偏差值呈现先减少后增大的趋势,19 a平均TVDI值为0.55,TVDI值范围为0.51~0.61,说明锡林郭勒地区整体处于轻旱状态。(2)19a间,锡林郭勒地区TVDI呈明显增加的面积占9.48%、轻度增加的面积占18.52%,增加的趋势主要分布在东乌珠穆沁旗东北部地区;TVDI呈明显减少的面积占28.65%、轻度减少的面积占9.03%,减少趋势的主要体现苏尼特右旗、苏尼特左旗、阿巴嘎旗和镶黄旗地区。19 a来锡林郭勒地区变化趋势为:东部强于西部。Hurst指数的平均值为0.44,大于0.44的地区占总面积的47.7%,整体干旱持续性略弱于反持续性。(3)TVDI与年平均气温相关关系较弱,而与月平均气温又较强的相关性。

The relationship between drought and meteorological factors is an important component in the study of arid ecosystems.Based on MODIS-TVDI data,this paper analyzed the spatiotemporal changes of drought in the Xilinguole grassland from 2000 to 2018 by combining RS and meteorological data to explore the correlation between drought and rainfall and temperature.The results show that over the 19 study period,the deviation of TVDI in the Xilinguole area first decreased and then increased,with an average TVDI value of 0.55 and a TVDI value range of 0.51-0.61.This indicates that the Xilinguole area was in a state of light drought during that period.The areas of TVDI increase and decrease from 2000 to 2018 were 88,932 km^2 and 113,647 km^2,respectively,with each accounting for 43.9%and 56.1%of the total area.The average value of the Hurst index is 0.44 and the area greater than 0.44 accounts for 47.7%of the total area.The overall drought persistence is slightly weaker than the antipersistence,and drought increased significantly in some areas,most of which were distributed in Taipusi Banner and Duolun County,from 2000 to 2018.In addition,the most obvious interannual changes occurred in 2010 and 2014 and the drought trend was particularly obvious in the typical steppe,desert steppe,and farming-pastoral ecotone lands.Additionally,the relationship between different meteorological elements and drought is different.TVDI is positively related to precipitation and temperature and TVDI is not significantly related to annual average temperature.