内蒙古草原干旱指标的研究

Study on drought index of Inner Mongolia grassland

干旱是内蒙古草原最严重的自然灾害,合理的干旱指标是监测预警干旱灾害的基础。在传统干旱指标的基础上,研究一种新的指标———相对蒸降差,该指标涉及到与大气降水、草地蒸发蒸散和土壤水分有关的因子,通过牧草供需水状况反映牧草受旱程度的一个指标。使用该指标对内蒙古草甸草原、典型草原和荒漠草原的牧草不同生育阶段的旱情进行统计、分析,并与降水距平百分率和土壤湿度指标加以对比,发现相对蒸降差更为精确实用且代表性强。

Drought is the most serious natural disaster in Inner Mongolia. Reasonable drought index is the base of drought monitoring and prediction. This article presented a new index （water deficit degree） based on traditional drought index. This new index included atmospheric precipitation, grassland evaporation and other factors related to soil moisture, reflecting drought degree by water supply and plant requirement. It was used to investigate and analyze drought condition at different plant growth stages on meadow, typical and desert grassland. It was also compared with precipitation percentage and soil moisture index, which indicated that the new index was more precise and practical.