长江中下游地区季节尺度气象干旱预测概念模型

A conceptual model for meteorological drought prediction at seasonal scale in the middle and lower reaches of Yangtze River

季节尺度气象干旱事件的发生与大尺度环流系统的异常运动密切相关。在识别长江中下游地区历史气象干旱事件的基础上,探讨了致旱环流系统异常特征,提取具有指示性意义的信号,以季节尺度气象干旱指数为干旱预测指标,应用偏最小二乘回归法构建了季节尺度干旱预测概念模型。模型率定和验证结果显示,率定期预测与实测的SPI3指数相关系数为0.64,验证期为0.56,表明该预测模型具有一定的预测效果。本研究方法可为区域季节尺度气象干旱预测和提前研判干旱发展情势提供技术支持。

The occurrence of meteorological drought events at seasonal scale is closely related to the abnormal movement of large-scale circulation system.Based on the identification of historical meteorological drought events in the middle and lower reaches of Yangtze River,the anomalous characteristics of drought-causing circulation system were discussed,and the indicative signals were selected.The conceptual model of drought prediction at seasonal scale was established by using the method of partial least squares regression with the seasonal meteorological drought index as the drought prediction index.The calibration and validation results show that the correlation coefficient between the predicted SPI3 index and the measured SPI3 index is 0.64 in the calibration period and 0.56 in the validation period,indicating that the prediction model has a certain prediction effect.This study can provide technical support for regional seasonal scale meteorological drought prediction and advance analysis of drought development situation.