基于WGEN天气发生器的石羊河流域降水模拟

为实现石羊河流域降水的模拟,通过改进WGEN天气发生器模型算法,选择民勤、永昌、武威、门源、乌鞘岭、景泰、靖远和西宁等8个站点,利用各站点1968～1997年雨季逐日降水资料进行了降水模拟参数估计,并在此基础上采用KS检验及绘制Q-Q图对模型在石羊河流域的适用性进行评价,发现除尾部拟合不理想外,GAMMA分布能较好地拟合石羊河流域的降水状况;利用各站点1998～2017年雨季逐日降水资料实测值与模拟值,选取月平均降水日数、日平均降水量、雨日平均降水量和月最大降水量作为评价要素,分别计算4个评价要素中模拟值与实测值的均方根误差、平均绝对百分误差和相关指数,以此来评价降水模拟效果。结果表明,该模型能较好地模拟石羊河流域除极端降水情况以外的其他降水状况。

Simulation of Precipitation in Shiyanghe River Basin Based on Weather-Generator

The algorithm of WGEN weather generator model was improved to simulate the precipitation in Shiyanghe River Basin. The datasets of the daily precipitation in rainy season of eight meteological stations during 1968-1997 were used to estimate correlative precipitation parameters, including Minqin, Yongchang, Wuwei, Menyuan, Wushaoling, Jingtai, Jingyuan and Xining. Based on the simulated data, the KS test and Q-Q plot were applied to assess the applicability of the model. The results show that the GAMMA distribution is relatively better for fitting the precipitation situation in Shiyanghe River Basin excepting that the matching of the curve tail was not perfect. In order to evaluate the simulation effect of precipitation, this paper selected four factors (average number of rainy days in each month/daily average precipitation/average precipitation in rainy day/monthly maximum precipitation) from both simulated data and observed values during 1998-2017. After calculating the relative evaluation indexes (root mean square error, mean absolute percentage error and correlation coefficient) of each factor, it shows that the improved WGEN model can simulate the rainfall situation in Shiyanghe River Basin well except some extreme rainfall.