四川省水稻孕穗—抽穗期低温连阴雨时空分布

Temporal and spatial distribution of low temperature continuous rain during booting-heading stage of rice in Sichuan province

【目的】为研究四川省水稻孕穗—抽穗期低温连阴雨灾害的时空分布特征,以期为四川省水稻不同生育期低温连阴雨防灾减灾提供科学依据。【方法】按照四川省地形地貌类型将水稻种植区划分为6个区域,即盆周边缘山地区、盆东平行岭谷区、盆南丘陵区、盆中浅丘区、盆西平丘区和川西南山地区,利用1961-2020年四川省21个农业气象观测站的逐日平均气温、最高气温、最低气温、降水量和日照时数资料,运用统计分析方法,结合低温连阴雨评估指标,分析四川省水稻孕穗—抽穗期低温连阴雨时空分布特征。【结果】(1)四川省水稻孕穗-抽穗期轻度、中度和重度低温冷害发生频率分别为:0%~32.5%、0%~44.8%和0%~50.3%,大值区均在川西南山地区,虽然轻度和中度低温冷害发生频率相对较低,但轻度低温冷害分布区域最广,中度低温冷害次之,重度低温冷害分布区域最小,只在川西南山地区;(2)轻度、中度和重度连阴雨灾害发生频率分别为:0.4%~3.8%、0%~5.2%和0%~0.5%,轻度和中度连阴雨灾害大值区均分布在盆南丘陵区;(3)1961-2020年低温连阴雨灾害发生频率为0%~9.1%,1991-2000年发生频率最高,为0%~9.1%,1961-1970年发生频率最低,为0%~3.3%;(4)1961-2020年低温冷害和低温连阴雨灾害发生频率随时间均通过0.05显著性检验,为下降趋势;连阴雨灾害发生频率随时间变化不明显,未通过0.05显著性检验。【结论】川西南山地区为低温连阴雨灾害发生频率高值区;四川省水稻孕穗—抽穗期低温连阴雨灾害近年来呈减少趋势,这与气候变暖大背景下,低温冷害和连阴雨灾害减少的结果一致。

【Objective】The present paper aimed to study the spatial and temporal distribution characteristics of low-temperature continuous rain disasters in rice during the heaving-heading stage in Sichuan province, in order to provide scientific basis for disaster prevention and reduction of low-temperature continuous rain disasters in rice at different growth stages in Sichuan province. 【Method】According to the topographic and geomorphic types of Sichuan province, the rice planting regions were divided into six regions, namely, the marginal mountain region around the basin, the parallel range-valley region in the east of the basin, the hilly region in the south of the basin, the shallow hilly region in the middle of the basin, the flat hill region in the west of the basin and the mountainous region in the southwest of Sichuan. Based on the data of daily mean temperature, maximum temperature, minimum temperature, precipitation and sunshine duration of 21 agricultural meteorological stations in Sichuan province from 1961 to 2020, the spatial and temporal distribution characteristics of low-temperature continuous rain during the period of rice starting from heading to heading were analyzed by using statistical analysis method combined with evaluation indexes of low-temperature continuous rain. 【Result】(i) The frequency of mild, moderate and severe cold damage of rice during booting and heading stage in Sichuan province was as follows: 0%-32.5%, 0%-44.8% and 0%-50.3%, and the large values were all in the southwest Mountain area of Sichuan. Although the occurrence frequency of mild and moderate cold damage was relatively low, the distribution area of mild cold damage was the widest, followed by moderate cold damage, and the distribution area of severe cold damage was the smallest, only in the southwest Mountain area of Sichuan.(ii) The frequency of mild, moderate and severe continuous rain disasters were 0.4%-3.8%, 0%-5.2% and 0%-0.5%, respectively.(iii) The frequency of low-temperature continuous rain disasters was 0%-9.1% from 1961 to 2020, 0%-9.1% from 1991 to 2000, and 0%-3.3% from 1961 to 1970.(iv) From 1961 to 2020, the frequency of low temperature cold damage and low temperature continuous rain disaster passed the significance test of 0.05 over time, showing a decreasing trend. The frequency of continuous rain disaster did not change significantly with time and did not pass the morphological significance test of 0.05. 【Conclusion】The frequency of low-temperature continuous rain disaster was high in the mountainous area of southwest Sichuan. In Sichuan province, the continuous low temperature rain disaster of rice during booting and heading stage showed a decreasing trend in recent years, which was consistent with the results of the reduction of low temperature cold damage and continuous rain disaster under the background of climate warming.