基于GIS的水量平衡模型在黄土高原地区土壤水分模拟中的应用

应用修正后Vrsmarty水量平衡模型对黄土高原地区2001-2010年间的土壤水分变化规律进行模拟。该模型综合考虑了土壤质地、植被类型、蒸发、降水等因素。模拟结果表明:黄土高原地区平均土壤水含量年内呈"正弦"曲线的变化规律,6月份土壤水含量最低为36.9mm,随着雨季到来,10月达到最高为74.3mm,而后逐渐降低。土壤水变化趋势可分为西北和东南两个区。西北区降雨量少,蒸散量大,全年土壤水含量很低,为1～40mm;东南区受降雨和蒸散周期性的变化的影响,土壤水变化周期性明显,秋末最高达200～240mm,夏初最低为60～100mm。全区的年平均降水为435.8mm,从东南向西北逐渐减少。全区年平均参考作物蒸散量为1 072.7mm,呈现出西北和东南偏高,东北和西南偏低的趋势。

The Application of GIS-based Soil Water Balance Model on Simulating Soil Water Dynamic Conditions in Loess Plateau

A continental scale GIS-based soil water balance model is used to simulate the spatial and temporal distribution and the changing trend of soil water in Loess Plateau from 2001 to 2010.Parameters such as soil type and texture,vegetation type,elevation,meteorological factors are taken into account in this model.Temporally,the average soil water in Loess Plateau change trend shows a "sine line",the minimum soil water content appears in June with the value of 36.9 mm and the maximum in October with the value of 74.3 mm.The soil water descends from October to next June while it ascends from June to October.Spatially,the northwest part of Loess Plateau has limited soil water with the value of 1～40 mm and narrow change range for the less precipitation and high evaporatranspiration,while in the southeast part of Loess Plateau,the soil water changes shows the similar pattern with precipitation temporal and spatial distribution patterns.In late autumn the soil moisture attains the highest value of 200～240 mm,while in early summer,it descends to the lowest point of 60～100mm.Average annual precipitation is 435.8 mm with the descending trend from southeast to northwest,and average annual crop referenced evaporatranspiration is 1 072.7 mm with higher values in southeast and northwest parts and lower values in southwest and northeast parts.