基于VCI的1982~2016年中国南方地区干旱时空变化特征分析

Analysis of the Spatial-Temporal Variation Characteristics of Drought Based on Vegetation Condition Index in Southern China from 1982 to 2016

干旱是最严重的自然灾害之一。本文基于1982~2016年NOAA/AVHRR气象卫星资料,以植被状态指数(VCI)为干旱监测指标,采用频率分析、趋势率分析、距平指数分析等方法,分析了中国南方地区干旱时空变化特征与发展趋势。结果表明,南方地区是干旱高发区,但绝大部分区域以轻旱与中旱为主,仅在四川盆地以及湖南少部分区域重旱发生频率稍高。1982~2016年间,南方地区VCI总体呈上升趋势,即大部分区域旱情趋于缓解。且VCI序列并非单向的变化,而是波动式上升,大致可分为1981~1990的缓慢上升期、1991~2000年的剧烈震荡期、2001~2016年的稳定上升期。本研究分析了中国南方地区旱情时空变化的规律,可为抗旱减灾相关措施与政策的制定提供科学依据。

Drought is one of the most serious natural disasters. This study presents a comprehensive spatio-temporal analysis of vegetative drought conditions that used the vegetation condition index (VCI) data product obtained from NOAA/AVHRR to reveal the vegetative drought patterns across China from 1981-2016. Considering the characteristics of VCI as drought indicators, multiple methods were designed for these analyses, including drought frequency analysis, trend analysis and anomaly index analysis. The results show that southern of China is a region with high vegetative drought frequency, but that most areas experienced only moderate periods of drought, only parts of Hunan and Sichuan basin experienced heavy drought. During 1982-2016, the VCI had an increasing trend in southern of China, indicating a reduced frequency of vegetative drought throughout the region. Moreover, the trend was wavelike rather than a one-way change and could be divided into 3 phases: 1) a slowly increasing phase from 1982-1990, 2) an intensively fluctuating phase from 1991-2000, 3) a steadily increasing phase from 2001-2016. This study analyzed the regular pattern of temporal and spatial variation of drought in southern China, and provided scientific basis for formulating relevant measures and policies for drought mitigation.