College of Water Resources and Architecture Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
Environ Sci Pollut Res Int. 2021 Jan;28(3):3644-3659. doi: 10.1007/s11356-020-10769-1. Epub 2020 Sep 14.
Drought is a major natural disaster that significantly impacts the susceptibility and flexibility of the ecosystem by changing vegetation phenology and productivity. This study aimed to investigate the impact of extreme climatic variation on vegetation phenology and productivity over the four sub-regions of China from 2000 to 2017. Daily rain gauge precipitation and air temperature datasets were used to estimate the trends, and to compute the standardized precipitation-evapotranspiration index (SPEI). Remote sensing-based Enhanced Vegetation Index (EVI) data from a moderate resolution imaging spectroradiometer (MODIS) was used to characterize vegetation phenology. The results revealed that (1) air temperature had significant increasing trends (P < 0.05) in all sub-regions. Precipitation showed a non-significant increasing trend in Northwest China (NWC) and insignificant decreasing trends in North China (NC), Qinghai Tibet area (QTA), and South China (SC). (2) Integrated enhanced vegetation index (iEVI) and SPEI variations depicted that 2011 and 2016 were the extremely driest and wettest years during 2000-2017. (3) Rapid changes were observed in the vegetation phenology and productivity between 2011 and 2016. In 2011, changes in the vegetation phenology with the length of the growing season (ΔLGS) = was - 14 ± 36 days. In 2016, the overall net effect changed at the onset and end of the growing season with ΔLGS of 34 ± 71 days. The change in iEVI per SPEI increased rapidly with a changing rate of 0.16 from arid (NWC, and QTA) to semi-arid (NWC, QTA and NC) and declined with a rate of - 0.04 from semi-humid (QTA, NC, and SC) to humid (SC) region. A higher association was observed between iEVI and SPEI as compared to iEVI and precipitation. Our finding exposed that north China is more sensitive to climatic variation.
干旱是一种主要的自然灾害，通过改变植被物候和生产力，显著影响生态系统的敏感性和弹性。本研究旨在调查 2000 年至 2017 年期间极端气候变化对中国四个次区域植被物候和生产力的影响。使用逐日雨量计降水和气温数据集来估计趋势，并计算标准化降水蒸散指数（SPEI）。利用中等分辨率成像光谱仪（MODIS）的基于遥感的增强植被指数（EVI）数据来描述植被物候。结果表明：（1）所有次区域的气温都有显著的上升趋势（P < 0.05）。降水在西北地区（NWC）呈非显著上升趋势，在华北地区（NC）、青海西藏地区（QTA）和华南地区（SC）呈不显著下降趋势。（2）综合增强植被指数（iEVI）和 SPEI 的变化表明，2011 年和 2016 年是 2000-2017 年期间最干旱和最湿润的年份。（3）2011 年至 2016 年间，植被物候和生产力发生了快速变化。在 2011 年，植被物候变化与生长季长度的变化（ΔLGS）为-14 ± 36 天。在 2016 年，生长季开始和结束时的整体净效应发生了变化，ΔLGS 为 34 ± 71 天。随着干旱（NWC 和 QTA）向半干旱（NWC、QTA 和 NC）地区的转变，iEVI 与 SPEI 的变化率迅速增加，为 0.16，而从半湿润（QTA、NC 和 SC）地区向湿润（SC）地区的转变，其变化率为-0.04。与 iEVI 与降水相比，iEVI 与 SPEI 之间的相关性更高。我们的发现表明，华北地区对气候变化更为敏感。
