区域植被对不同时间尺度气象干旱的响应——以贵州省为例

为探究贵州省植被生长变化趋势对多时间尺度气象干旱的响应,基于2001—2020年的逐月MODIS-NDVI、EVI影像和气象数据,利用皮尔森相关系数、slope趋势性分析等方法,对贵州省20 a的植被生长状况及气象干旱时空变化特征进行了分析。结果表明:(1)贵州省不同时间尺度下的SPEI在整体上呈现出缓慢增加趋势,表明干旱程度有所降低; 空间分布上干旱化趋势表现在北部的遵义、铜仁及黔西南地区。(2)贵州省植被生长状况整体呈现出增加趋势,空间分布上的黔东南地区以降低趋势为主,毕节西部地区以增长趋势为主;(3)贵州省植被生长状况与不同时间尺度的气象干旱呈现出不同程度的正相关性,以贵州省植被在黔西南和北部地区对干旱的响应最强,其次为贵阳和毕节东部; 不同的土地利用类型中,草地对SPEI₃的响应最强,其次为耕地和林地; 生长季内的不同植被类型对SPEI₃和SPEI₁₂的响应较强。综上,贵州省植被和气象干旱时空分布特征存在一定的差异性,且不同植被类型对不同时间尺度气象干旱的响应情况也有所差别。

Response of Vegetation to Meteorological Drought in Watershed at Different Time Scales

In order to explore the response of vegetation growth trend to multi-time scale meteorological drought in Guizhou Province, based on monthly MODIS-NDVI and EVI images and meteorological data from 2001 to 2020, Pearson correlation coefficient, slope trend analysis and other methods were used to analyze the vegetation growth status and spatial and temporal variation characteristics of meteorological drought in Guizhou Province in 20 years. The results show that:(1)the different time scales of SPEI in Guizhou Province showed a trend of slow increase on the whole, indicating that the degree of drought had decreased; the spatial distribution of the aridity trend presented in Zunyi, Tongren and Southwest Guizhou;(2)the overall vegetation growth in Guizhou Province showed a slow increasing trend, but there were differences in spatial distribution; the vegetation growth in southeast Guizhou Province showed a decreasing trend, while that in the west of Bijie City showed an increasing trend;(3)there was a positive correlation between vegetation growth and drought on different time scales in Guizhou Province; the vegetation in southwest and northern Guizhou Province had the strongest response to drought, followed by Guiyang and eastern Bijie; among different land use types, grassland had the strongest response to SPEI₃, followed by cultivated land and forest land; the response of different vegetation types to SPEI₃ and SPEI₁₂ was stronger in the growing season. In conclusion, there are some differences in the spatial and temporal distribution characteristics of vegetation and meteorological drought in Guizhou Province, and different vegetation types have different responses to meteorological drought at different time scales.