基于SARIMA模型的赣江流域近50年参考作物需水量预测

Forecast of Reference Crop Evapotranspiration in the Ganjiang River Basin in Recent 50 Years Based on SARIMA Model

基于赣江流域12个代表气象站点1961—2010年的逐日气象观测资料,采用Penman-Monteith公式计算了各站点逐日参考作物需水量,整理得到赣江流域及上、中、下游3个子区域的参考作物需水量年度和月度数据,对其变化特征进行了分析。赣江流域50 a参考作物需水量年际变化较大,年内变化呈现出明显的季节性特征。在考虑了季节性因素的基础上,利用BIC准则法确定模型最佳阶数,建立了赣江流域参考作物需水量的季节性ARIMA模型,对研究区域的参考作物需水量进行了拟合与预测,并验证了模型的显著性。预测结果表明,模型的平均相对误差在合理范围之内。

Based on the daily meteorological observation data of 12 representative meteorological stations in the Ganjiang River Basin from 1961 to 2010,the Penman-Monteith formula was used to calculate the daily reference crop evapotranspiration of each station.The annual and monthly reference crop evapotranspiration data were divided into three parts according to the upper,middle and lower reaches,which were analyzed for their changing characteristics.The results showed that the interannual variation of the 50-year reference crop evapotranspiration in the Ganjiang River Basin was relatively large.The intra-annual changes showed significant seasonal characteristics.Based on the seasonal factors,the BIC criterion method was used to determine the optimal order of the model and the seasonal ARIMA model was established to fitted and predicted the reference crop evapotranspiration of Ganjiang River Basin and also validate its significance.The prediction shows that average relative error of the model is within reasonable range.