基于滑动平均-加权马尔科夫链的宁夏石嘴山市年降雨量预测

为了给农业发展与决策提供理论支持,根据石嘴山市5个气象站(大武口站、平罗站、石炭井站、陶乐站、惠农站)1960—2008年的降雨资料,进行3 a滑动平均计算.采用均值-标准差分级法计算降雨量分级,将降雨序列分为枯水年、偏枯年、平水年、偏丰年和丰水年5个状态.利用精度检验后的加权马尔科夫预测模型对石嘴山市2007年和2008年滑动平均降雨量进行区间估计,并根据状态特征值结合线性插值的方法计算了滑动平均降雨量的预测值,由此得出2009年和2010年的年降雨量预测值.最后讨论了各状态重现期.计算结果表明:石嘴山市2007年和2008年的3 a滑动平均降雨量分别是185.42,168.28 mm;2009年和2010年的年降雨量分别为135.11,146.88 mm,均处于偏枯年状态;平水年和偏丰年重现期最小,枯水年重现期最大.

Precipitation Prediction on Shizuishan City in Ningxia Province Based on Moving Average and Weighted Markov Chain

In order to provide a theoretical support for agricultural development and decision,the rainfall classification was calculated with the mean-standard deviation classification method according to rainfall data collected at five weather stations from 1960 to 2008 in Shizuishan City,such as Dawukou station,Pingluo station,Shitan station,Taole Station,Huinong station,and after triennium moving average calculating,the rainfall series were divided into dry year,weak dry year,normal year,weak water logging year,and water logging year,the interval estimation on the moving average annual rainfall was made for the year of 2007 and 2008 with the weighted Markov forecasting method after accuracy verification,and in accordance with the state eigenvalue and linear interpolation methods,the predicted moving-average rainfall values were calculated,as well as the annual rainfalls for 2009 and 2010 were forecasted.Finally,the issue of return period of each state was discussed.The results show that,the three-year moving average rainfall for 2007 and 2008 in Shizuishan City is 185.42 mm and 168.01 mm respectively,and the annual rainfall for 2009 and 2010 is 135.11 mm and 146.07 mm respectively.The return period of normal year and weak water logging year is smallest,and the return period of dry-year is largest.