基于GIS的内蒙古自治区植被生态需水量研究

GIS-based Study of Ecological Water Requirement of Vegetation in Inner Mongolia Autonomous Region

[目地]分析计算内蒙古自治区不同典型分区的植被生态需水量,为该区域水资源管理和生态保护提供科学建议。[方法]以Penman-Monteith公式为基础,利用实测与多源遥感数据,对1990—2020年内蒙古自治区4个典型区域(西部地区、中部地区、东部地区、东北部地区)植被生态需水量(ecological water requirement,EWR)和单位面积植被生态需水量(ecological water requirement for vegetation per unit area,ET)进行反演,并分析其时空变化的主导因素。[结果](1)时间上,30 a间EWR呈现先降后升的趋势,就区域总量来看西部地区较为稳定,维持在3.00×10^(10) m^(3)左右;中部与东部地区在6.00×10^(10) m^(3)左右,变化幅度较大,年间最大变幅超1.00×10^(10) m^(3);东北部地区高,且稳定在1.00×10^(11) m^(3)左右。(2)空间上,总体呈现出自西向东逐渐升高的态势且东西差异巨大,东北部区单位面积植被生态需水量(ET)均值较西部地区高近250 mm。[结论]降水蒸发主导下的气候因素与土地覆盖类型变化主导下的人为因素是内蒙古自治区植被生态需水量变化的关键因素,后者影响程度要大于前者。

[Objective] The ecological water requirement(EWR) of vegetation in different typical zones for the rational allocation of water resources in the Inner Mongolia Autonomous Region was analyzed and calculated to provide scientific suggestions for water resources management and ecological protection in this region.[Methods] Based on the Penman-Monteith formula,this study used measured and multi-source remote sensing data to invert EWR and the ecological water requirement per unit area(ET) for vegetation in four typical regions(western,central,eastern,and northeastern regions) of the Inner Mongolia Autonomous Region from 1990 to 2020.The dominant factors of spatiotemporal variation of ET were determined.[Results](1) EWR showed a trend of decreasing and then increasing over the 30-year study period,with the western region being more stable(maintaining an EWR of around 3.00×10^(10) m^(3)).The central and eastern regions had EWR of around 6.00×10^(10) m^(3),with a large variation and a maximum variation of over 1.00×10^(10) m^(3) between years.The northeastern region EWR values were higher and stable at around 1.00×10^(11) m^(3).(2) EWR was higher in the east and lower in the west,and varied greatly from east to west,with the mean ET value in the northeastern region being nearly 250 mm higher than in the west.[Conclusion] The climatic factors(primarily precipitation and evaporation) and anthropogenic factors(primarily land cover type change) were the key factors for the change of ecological water requirement of vegetation in the Inner Mongolia Autonomous Region,with the latter being more influential than the former.