阴山北麓荒漠草原干旱气象因子分析

Analysis of meteorological factors affecting drought in a desert steppe of the northern foot of Yinshan Mountain

草原是西部生态环境建设的关键部分,其生态系统极易受到破坏。近年来荒漠草原干旱灾害频发,以内蒙古阴山北麓荒漠草原生态水文国家野外科学观测研究站为试验区,通过监测不同坡位的降水变化,分析气象因子与干旱指标PA值之间的联系与作用,并构建了回归模型。结果表明:(1)阴山北麓荒漠草原不同坡位的降水量为:下坡>中坡>上坡,对应的干旱指数PA值为:上坡_(PA)>中坡_(PA)>下坡_(PA)。(2)从各时间尺度观测可知:月尺度分析发现各坡位均出现不同程度的干旱现象,干旱频率较高;季尺度分析发现只在冬季出现轻旱现象;年尺度分析发现近5 a该区域未达到干旱阈值。说明该地区年均降水充足,未发生干旱灾害。(3)根据降水量、气温、风速等主要气象因子与干旱指数PA值构建的多元回归模型为:YPA=78.799+0.255_(x1)-3.395_(x2)-1.831_(x3),R^(2)为0.994,模型的拟合程度高,可以较好的反应出该区域的干旱情况。为进一步研究多气象因子与各类干旱指标之间的关系,以及构建旱情评价体系提供理论依据。

Steppe is a key part of the ecological environment construction in the west region,and its ecosystem is very fragile.In recent years,desert steppe drought disasters occur frequently.Taking the Yinshanbeilu National Field Research Station of Desert Steppe Eco-Hydrological System in Inner Mongolia as the experimental area,the precipitation changes at different slope positions are monitored,the relationship and function between meteorological factors and drought index PA value are analyzed,and a regression model is constructed.The results show that:(1)the precipitation at different slope positions of the desert steppe at the north foot of Yinshan Mountain is:downhill>middle slope>uphill,and the corresponding drought index PA value is:uphillPA>middle slopePA>downhillPA(2)From the observation of each time scale,monthly scale analysis shows that there are different degrees of drought at each slope position,and the drought frequency is high;Seasonal scale analysis shows that light drought occurred only in winter;The annual scale analysis found that the region did not reach the drought threshold in recent 5 years.Overall,the average annual precipitation in this area is sufficient and there is no drought disaster.(3)The multiple regression model constructed according to the main meteorological factors such as precipitation,air temperature and wind speed and the drought index PA value is:Y_(PA)=78.799+0.255_(x1)-3.395_(x2)-1.831_(x3),R^(2)=0.994,the fitting degree of the model is high,which can better reflect the drought situation in the region.It provides a theoretical basis for further studying the relationship between multi meteorological factors and various drought indicators,as well as constructing drought evaluation system.