Characteristics of Continuous Rain Weather in the 2023 Wheat Harvest Period and the Influence on Winter Wheat in Jiangsu Province
Based on the precipitation observations of automatic weather stations,the ECMWF rean-alysis data,and the growth period and yield data of winter wheat in Jiangsu Province,the causes of large-scale continuous rain process in late May 2023 are investigated,and the background characteristics of this rain process and atmospheric circulation are analyzed.Moreover,the impact of the continuous rainy process on the maturation and harvest progress of winter wheat in Jiangsu Province is also discussed.The results show that:(1)This continuous rain process was obviously featured with long duration,wide range,large rainfall amount and short-time intense precipitation,being accompanied by high temperature and fewer sunshine hours.From May 26 to 31,the rainfall amount in Jiangsu Province was 2 to 4 times more than that in the same period of normal years,rainfall days were 40％more than in the same period of normal years,and the sunshine hours to the north of the Yangtze River were 50％to 80％less than in the same period of normal years.(2)At 500 hPa,the intensities of the high pressure near the Ural Mountains and the low trough near Lake Baikal were 40-60 gpm larger than normal,and the subtropical high was stronger and about 5 latitudes northward.At 850 hPa,the southwest airflow at the edge of the subtropical high and the outer cloud system of Typhoon Mawar provided favorable water vapor transport conditions,and the multi-system interaction contributed to this continuous rain process.(3)Continuous rain and less sunshine are not conducive to crop photosynthesis,so the harvest period of winter wheat in Jiangsu was delayed by 2-3 days compared with that in 2008-2022,causing the occurrence of the phe-nomenon"pre-harvest sprouting"in some wheat fields to the north of Huaihe River,where the winter wheat was affected more serious than in southern Jiangsu.As a result,in Xuzhou city,the 1000-grain weight of winter wheat in 2023 was reduced by 3.94 g compared to the situation in 2022,which was mainly related to the growth period and variety of wheat as well as the intensity of continuous rain.In the recent 16 years,the average frequency of wheat harvest affected by continuous rain in Jiangsu is 3.2 years/time.Therefore,appropriately early sowing,early harvesting at mature stage,and breeding wheat varieties that are premature or resistant to pre-harvest sprouting can avoid the negative impact of continu-ous rain during wheat harvest period and reduce or avoid the grain loss.
万方数据
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