摘要
随着修订风蚀方程(RWEQ)的提出,采用增加了冻结因子的气候因子(WF)表达风蚀气候侵蚀力更具有科学性和必要性.基于中国北方风蚀区157个气象站1980-2016年的观测数据,逐月计算了各站点气候因子,并探讨了气候因子时空分布变化特征及影响因素.结果表明:①1980-1997年,年气候因子值表现为快速下降,从940.46 kg/m下降到273.03 kg/m;而1998-2016年,年气候因子值表现相对稳定,在139.81～398.85 kg/m范围内波动.②春季气候因子值约占全年63％,其变化也显著高于其它季节,这也是土壤风蚀发生在春季的主要原因.③气候因子的高值区分布在新疆东部、青海西部、40°N以北的内蒙古中西部,这与气压中心和高大山体地形分布有关.
Abstract
Wind is the prime power of soil wind erosion.The Weather Factor(WF)of the Revised Wind Erosion Equation(RWEQ)are the most widely used expressions of wind erosion climatic erosivity.Based on the actual situ-ation of the study area,soil freezing factor(FD)was added into the Weather Factor(WF),and the modified WF was used to evaluate wind erosivity.By calculating the yearly variation of WF,WF in different seasons and WF in differ-ent months,the temporal and spatial distribution changes of WF were drawn.WF is performed using more than wind velocity,precipitation,temperature and snow cover series at 157 national meteorological stations in 1980-2016.The following conclusions were drawn:1)WF value in the study area descended from 1980 to 1988,with an average an-nual descend rate of about 37.20 kg/m,and it was relatively stable from 1989 to 2016,with an average value of about 190.36 kg/m;2)WF value in spring accounts for about 63％of the whole year,and WF decreased most significantly in spring,with an annual descend rate of 34.94 kg/m,while the annual descend rates in summer and autumn were 3.19 kg/m and 1.87 kg/m respectively.3)On the spatial distribution,the high value area of average WF over years are mainly distributed in north 40°N of the midwestern Inner Mongolia,the eastern Xinjiang and the western Qinghai,and the low value areas were mainly distributed in the southern Xinjiang,the eastern Qinghai and the southeast of the study area.
万方数据