摘要
Quantifying the relationship between the drought severity index and climate factors is crucial for predicting drought risk in situations characterized by climate change. However, variations in drought risk are not readily discernible under conditions of climate change, and this is particularly the case on the Tibetan Plateau. This study examines the correlations between the annual drought severity index(DSI) and 14 climate factors(including temperature, precipitation, humidity, wind speed, and hours of sunshine factors), on the Tibetan Plateau from 2000 to 2011. Spatial average DSI increased with precipitation and minimum relative humidity, while it decreased as the hours of sunshine increased. The correlation between DSI and climate factors varied with vegetation types. In alpine meadows, the correlation of the spatial DSI average with the percentage of sunshine and hours of sunshine(P<0.001) was higher compared to that in alpine steppes(P<0.05). Similarly, average vapor pressure and minimum relative humidity had significant positive effects on spatial DSI in alpine meadows, but had insignificant effects in alpine steppes. The magnitude of DSI change correlated negatively with temperature, precipitation, and vapor pressure, and positively with wind speed and sunshine. This demonstrates that the correlation between drought and climate change on the Tibetan Plateau is dependent on the type of ecosystem.
在气候变化条件下,干旱如何发生改变仍然没有搞清楚。量化干旱与气候因子之间的关系是预测全球气候变化背景下未来干旱风险发生的关键。本文对2000?2011年青藏高原年干旱严重度指数(DSI)与气候因子的相关性进行了研究。空间平均DSI随降水量的增加及相对湿度降低而增加,随日照的增加而减少。DSI与气候因子的相关程度随植被类型的不同而不同。以高寒草甸为例,空间DSI平均值与日照百分率(SP)和日照时数(SH)的相关程度(P<0.001)高于高寒草原(P<0.05);在高山草原,空间DSI平均值与平均水汽压(Ea)和最低相对湿度(MIRH)的相关性不显著,但在高山草甸为极显著水平或显著水平以上(P<0.05)。DSI的变化幅度随温度、降水和水汽压的增加而减小,随风速和日照的增加而增大。因此,要弄清干旱与气候变化的关系,需要进一步考虑青藏高原的生态系统类型及其局地气候。
基金
The National Key Research and Development Program(2016YFC0502001)
The National Natural Science Foundation of China(41761008)。
