Climate characteristics and cause analysis of continuous rain events during growth duration of rice in Chongqing from 1991 to 2020
Studying the occurrence patterns and causes of continuous rain during growth duration of rice in Chongqing could scientifi-cally guide rice cultivation and prevent and mitigate disasters.Based on meteorological data from 1991 to 2020,rice growth period ob-servations,and NCEP/NCAR reanalysis data in Chongqing,this study explores the climatic characteristics and atmospheric circulation patterns of continuous rain events across different rice planting regions and growth stages in Chongqing.The findings indicate a general decreasing trend in continuous rain events across all planting regions.Notably,in the central Chongqing it displayed the most signifi-cant decrease trend with a climate tendency rate of-0.33 per decade.Although in the southeastern region the proportion of stations with continuous rain was highest(1.18),it showed the weakest decreasing trend.Conversely,in the northeastern region the proportion of stations with continuous rain was lowest at 0.55,and the trend of decreasing continuous rain was most pronounced there.The frequency of continuous rain was highest during the vegetative growth stage and lowest during the reproductive stage.Spatially,the frequency of continuous rain was greatest in southeastern Chongqing,the maximum was 1.80,and lowest in northeastern Chongqing,the minimum was 0.27.The areas with higher frequencies were predominantly in the southern parts of Chongqing,varying slightly across different growth stages,while the lowest frequencies were consistently found in the northeastern parts.During the vegetative stage,continuous rain was most frequent.All regions were generally influenced by a negative geopotential height anomaly,which reduced the north-south geopostitial height gradient,making it easier for cold air to move south and result in continuous rain.In the southeastern Chongqing,wa-ter vapor originated from the Pacific Ocean and carried by the southeast periphery of the subtropical high.Compared to the seedling stage,the water vapor conveyor belt during the vegetative stage was further south,moving in a southwest direction.
万方数据
维普
