摘要
水分利用效率(WUE)作为陆地生态系统中碳水循环之间的重要连接,衡量了生态系统水分消耗与碳积累之间的关系。本文基于MODIS净初级生产力(NPP)和蒸散(ET)产品数据,分析了中国干旱半干旱区WUE的时空变异及其影响因素。结果表明:1) 2001至2014年,整个研究区NPP和ET均呈上升趋势,WUE呈下降趋势;2) WUE低值区主要分布在青藏高原地区,其年际变化呈上升趋势;WUE高值区主要分布在新疆北部和松嫩平原西部,WUE年际变化呈下降趋势;3) 研究区大部分地区WUE与降水呈正相关。在青藏高原高寒草甸区,WUE与温度呈负相关,而在内蒙古高原温带草甸区,WUE与温度呈正相关。4) 不同时间尺度的SPEI与WUE相关性趋势大体一致,即干旱促进大部分研究区植被WUE且SPEI-12与WUE的显著相关比例最大。
As an important link between carbon and water cycle in terrestrial ecosystems, water use efficiency (WUE) measures the relationship between water consumption and carbon. In this paper, net pri-mary production (NPP) and evapotranspiration (ET) data from MODIS products were used to ana-lyze the spatial and temporal characteristics of water use efficiency in arid and semi-arid areas of China, and the response of vegetation to climate factors. Results showed that, 1) During 2001-2014, both NPP and ET showed an upward trend, while WUE showed a downward trend. 2) Spatially, the low WUE values are mainly distributed in the Tibetan plateau and show an upward trend;while the high WUE values are mainly distributed in the north of Xinjiang and the west of Songnen plain. 3) WUE of different vegetation types is shown as follows: Evergreen Needle leaf forest >Croplands >Mixed forest >Closed shrub lands >Grasslands >Open shrub lands. 4) Precipitation is positively correlated with most areas of the study area;temperature is negatively correlated with the alpine meadow on the Tibetan plateau and positively correlated with the temperate meadow on the Inner Mongolia plateau. A certain degree of drought can promote water use efficiency of vegetation.
出处
《地理科学研究》
2021年第2期126-136,共11页
Geographical Science Research
