青海省冬春季风蚀气候侵蚀力和起沙风日数的区域变化差异特征

Characteristics of Regional Variation of Wind Erosion Climatic Erosivity and Number of Wind Days in Winter and Spring in Qinghai Province

利用1961—2015年青海省43个气象站观测资料,选择联合国粮农组织给出的风蚀气候因子指数计算公式,计算和统计了青海省和4个不同生态功能区冬、春季风蚀气候因子指数值和起沙风日数,以此分析研究了风蚀气候侵蚀力和起沙风日数的基本变化特征。结果表明:青海省和4个生态功能区冬、春季风蚀气候因子指数和起沙风日数整体上呈现显著减小趋势;风蚀气候因子指数和起沙风日数的空间分布特征完全一致,均整体呈现出从西部向东部减小的分布特点。以大柴旦、格尔木、曲麻莱和杂多为界分为东西两区,东区的C值和起沙风日数大部分分别在40,10 d以下,以诺木洪、天峻和刚察为中心分别向南向北逐渐减小;西区的C值和起沙风日数均分别大于40,10 d以上,从西向东逐渐减小;冬春季风蚀气候因子指数和起沙风日数分别在1992年、1997年发生突变,且分别在1995年和1999年进入显著下降趋势;影响青海省和4个生态功能区冬、春季风蚀气候因子指数的气象因素存在差异,同一影响因素在不同地区的影响程度也不同。在干旱的柴达木盆地主要受制于风速的作用,东部农业区和环青海湖区则受风速和降水量的影响,三江源地区和全省则受风速、温度和降水等的共同作用与影响;青海省和4个生态功能区气候呈暖湿化发展、植被覆盖缓慢上升及风速显著下降趋势,将为防治风蚀气候因子指数的发生提供有利条件。

By using the observation data of 43 meteorological stations in Qinghai Province in 1961—2015 years, and the wind erosion climate factor index formula given by Food and Agricultural Organization of the United Nations, the wind erosion climate factor index and the number of wind days in the 4 different ecological functional regions of Qinghai in winter and spring were calculated and counted. Based on the above analysis, the basic characteristics of the wind erosion climatic erosivity and the number of wind days were discussed. The results showed that the wind erosion climate factor index and the number of wind days in winter and spring in the 4 different ecological functional regions of Qinghai presented the significant decreasing trend, and the spatial distribution characteristics of the wind erosion climate factor index and the number of wind days were all the same, showing the decreasing distribution from the west to the east. It was divided into the eastern and western areas by taking the Dachaidan, Golmud, Qumalai and Zaduo as the boundary. The C value and the number of wind days in the eastern region were mostly below 40 d and 10 d, respectively, and decreased from Nuomuhong, Tianjun and Gangcha to the south and the north;the C value and the number of wind days in the western region were greater than 40 d and 10 d, respectively, and gradually decreased from the west to the east. The mutations of the wind erosion climate factor index and the number of wind days in winter and spring occurred in 1992 and 1997, respectively, and entered a significant downward trend in 1995 and 1999, respectively. The meteorological factors affecting the wind erosion climate factor index in winter and spring in the 4 different ecological functional regions of Qinghai were different, and the influence degree of the same influence factors in different regions was also different. It was mainly controlled by wind speed in arid Qaidam Basin, affected by wind speed and precipitation in the eastern agricultural area and the Qinghai Lake area, and affected by wind speed, temperature and precipitation in the Three-River headwater area and the whole province. The development of climate warm and humidification, the slow rise of vegetation cover and the significant decreasing trend of wind speed in the 4 different ecological functional regions of Qinghai, will provide favorable conditions for controlling the occurrence of wind erosion climate factor index.