我国北方半干旱区草地水分供需状况研究

利用半干旱区181个站点40a的气象资料,依据伊万诺夫湿润系数对半干旱区草地进行气候分区,采用计算精度较高的FAO Penman-Monteith方法(1998)计算可能蒸散。在计算不同草地类型草地蒸散系数的基础上,计算半干旱区草地实际蒸散量,通过水分盈亏和水分订正系数等来分析评价不同草地类型的水分供需状况。结果表明:不同草地类型的蒸散系数也不同,草甸草原的蒸散系数最大,荒漠的蒸散系数最小;不同草地类型的实际需水量也不同:草甸草原>典型草原>荒漠化草原>草原化荒漠>荒漠;在半干旱地区实施退耕还草有利于水资源的可持续利用和生态环境的改善。

Study on the Moisture Budget of the Grasslands in the Semiarid Regions in North China

In this paper, the climatic divisions of the grasslands in the semiarid regions in China are delimited by using humid indexes based on the meteorological data collected by 181 meteorological stations in the semiarid regions in recent 40 years, and the potential evapotranspirations of the different types of grasslands are calculated by using the FAO Penman-Monteith method, on which the actual evaotranspirations of the grasslands in the semiarid regions are calculated. The moisture supply and demand of the different types of grasslands are analyzed and evaluated with the moisture budget and the revised moisture coefficients The results reveal that the evapo transpiration coefficient is different from the different types of grasslands, it is the highest in the meadow grass lands and the lowest in the deserts; the moisture demand is also different from the different types of grasslands, that is the moisture demand is in an order of meadow grasslands > typical grasslands > desertified grasslands> grassland desert>desert; it is advantageous for the sustainable utilization of water resources and the improve ment of the ecological environment to implement the project of withdrawing from farming to afforesting and grass planting.