摘要
基于植被对气象干旱事件的响应特征构建了植被敏感性及脆弱性的评估方法:基于长序列降水及潜在蒸散发数据和日诱导叶绿素荧光指数构建日尺度标准化指数,以2022年长江特大气象干旱事件为例,计算相关系数(CC)、累积响应时间(RT)及响应敏感度(RS)评估植被对干旱响应的敏感性;利用历时响应比(DRR)和烈度响应比(IRR)评估植被对干旱事件响应的脆弱性.结果表明:对于2022年长江流域特大气象干旱事件,(1)上游常绿针叶林及草甸敏感性低(中位CC=0.36,0.44;中位RS=-1.72,-1.58);中下游耕地敏感性最高(中位CC=0.68,中位RS=-1.37),稀树及多树草原敏感性高于林地(中位CC:林地=0.41~0.49,多树草原=0.64,稀树草原=0.61;中位RS:林地=-1.61~-1.57,多树草原=-1.44,稀树草原=-1.40).(2)上游常绿针叶林脆弱性高于其他林地(中位DRR:针叶林=1.04,其他林地=0.85~0.97;中位IRR:针叶林=0.94,其他林地:IRR=0.76~0.88);草甸脆弱性高于中下游多树及稀树草原(中位DRR:草甸=1.28,多树草原=0.74,稀树草原=0.88;中位IRR:草甸=1.24,多树草原=0.74,稀树草原=0.80);耕地脆弱性低(中位DRR=0.77IRR=0.72).(3)空间分布上,上游金沙江流域是高脆弱性热点区域;中下游的四川盆地及汉江流域耕地聚集,是高敏感性热点区域.基于研究结论,当极端干旱事件发生时,可根据不同植被的响应特点开展植被监测和恢复措施,从而保护植被不发生退化和永久性损害.
A method for assessing vegetation sensitivity and vulnerability to meteorological droughts was proposed in this study.Standardized indices were developed based on precipitation, evapotranspiration, and solar-induced chlorophyll fluorescence data.The sensitivity of vegetation to meteorological drought was quantified by using Correlation Coefficient(CC), Response Time scale(RT), and Response Sensitivity(RS), while vulnerability was assessed by Duration Response Ratio(DRR) and Intensity Response Ratio(IRR). The results indicated that in the vegetation response assessment for meteorological drought of 2022 in Yangtze River Basin,(1) Low sensitivity(median CC=0.36, 0.44;median RS=-1.72,-1.58) was observed in evergreen needleleaf forest and grassland exhibited of upstream region. Whereas, the highest sensitivity(median CC=0.68, median RS=-1.37) was shown in cultivated land, and the sensitivity of(woody) savannas surpassed that of forests(median CC: forests=0.41~0.49, woody savanna=0.64, savanna=0.61;median RS: forests=-1.61~-1.57, woody savanna=-1.44, savanna=-1.40) in the middle and lower reaches.(2) The vulnerability of evergreen needleleaf forest was obviously higher than that of other forests(median DRR: needleleaf forest=1.04, other forests=0.85~0.97;median IRR: needleleaf forest=0.94, other forests: IRR=0.76~0.88). Meteorological drought was found to have a greater impact on grasslands than on(woody) savannas in the middle and lower reaches(median DRR:grassland=1.28, woody savanna=0.74, savanna=0.88;median IRR: grassland=1.24, woody savanna=0.74, savanna=0.80). Low vulnerability was exhibited in cultivated land(median DRR=0.77, IRR=0.72).(3) the Jinsha River basin, with the high average elevation, was identified as high vulnerability hotspot, while the Sichuan Basin and the Han River basin were high sensitivity hotspots due to the aggregated croplands. Therefore, to prevent further degradation and irreversible damage, vegetation monitoring and restoration strategies should be conducted according to various responses of vegetation to meteorological drought.
作者
赵乾佐
张璇
费俊源
许杨
李冲
郝芳华
ZHAO Qian-zuo;ZHANG Xuan;FEI Jun-yuan;XU Yang;LI Chong;HAO Fang-hua(College of Water Sciences,Beijing Normal University,Beijing 100875,China;School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2024年第9期5134-5144,共11页
China Environmental Science
基金
国家自然科学基金资助项目(42271023)。
关键词
气象干旱
敏感性
脆弱性
植被响应
长江流域
meteorological drought
sensitivity
vulnerability
drought response
Yangtze River Basin
