淮河上游冬小麦生长关键期旱涝灾害阈值研究

Threshold Drought and Flooding at Critical Growth Period of Winter Wheat in the Upper Reach of Huai River

利用淮河上游地区1961-2015年13个气象站逐日降水数据,计算冬小麦生长关键期(2、3、4月)1个月尺度及3个月尺度SPI值,结合冬小麦产量数据,确定生长关键期对产量灾损率影响的具体时段,在此基础上分析了降水量变化及旱涝灾害空间分布,建立了SPI值与产量灾损率之间的定量关系。结果表明,(1)生长关键期(SPI3)和4月(SPI1_4)SPI值均与产量灾损率相关性程度高,分别通过0.01和0.05显著性水平检验;2个时段降水量变化整体呈减少趋势,且旱涝灾害空间分布存在一定的差异;(2)当SPI3值和SPI1_4值分别为-2.23和-1.82时,达到决定发生旱灾时产量灾损的阈值;(3)SPI3值和SPI1_4值与产量灾损率相关系数分别为0.94和0.82,在典型涝灾年,SPI值与产量灾损率具有线性关系。

Using the precipitation measured daily from 1961--2015 at 13 weather stations in the upper reach of Huai River, we calculated the monthly average and quarterly average SPI of winter wheat during its main grow- ing season （February to March） respectively. Based on the harvest time, we calculated the yield loss rate due to the occurrence of drought and/or flooding in different growing stages, from which we analyzed the spatial distri- bution and variation of the precipitation, flooding and drought, as well as their relationship with the SP1. The re- suits showed that there was a close correlation between SP13 for critical growing stage and the SP1 for April （SP14）, which passed both the 0.01 and 0.05 confidence tests. The precipitation during the two periods decreased, and there was a difference in the spatial distributions of the drought and flooding as well. The threshold at which a drought could cause agricultural loss was when SP13 was -2.23 and SPI1_4 was -1.82. The correlation coeffi- cients of SP13 and SPI1_4 with the agricultural loss rate were 0.94 and 0.82 respectively, and there was a linear re- lationship between SP1 and agricultural loss rate in typical flooding years.