Abstract:Against the backdrop of global warming, understanding the occurrence patterns of continuous rain during the summer harvest and planting period is crucial for avoiding the increasingly frequent risks of continuous rain disasters during the maturation and harvest stages of rapeseed/wheat, as well as the sowing and emergence stages of rice/dryland crops. Using data on meteorology, soil moisture, and crop production progress from 1981 to 2020, this study calculates the continuous rain intensity index based on the start and end times of the summer harvest and planting period and the criteria for determining continuous rain. It establishes the corresponding relationship between the continuous rain intensity index and the increment of 10 cm soil relative humidity and defines the impact levels of continuous rain intensity during the summer harvest and planting period. By employing spatial-temporal statistics and EOF (Empirical Orthogonal Function) methods, the study classifies different regions, decades, intensity levels, and stages to analyse the spatial-temporal distribution characteristics and occurrence patterns of continuous rain during the summer harvest and planting period in Jiangsu Province. The results show that, in terms of time, the number of continuous rain occurrences in southern, central, and northern Jiangsu is 0.38 times/year, 0.72 times/year, and 0.98 times/year, respectively. The high-incidence period is concentrated in 2010-2020, with the occurrence intensity showing an upward trend of 0.15-0.25 per decade. The periods of strong occurrence are concentrated in 2001-2020, and mild, strong, extra strong continuous rains mostly occur in late May-early June and late June. In terms of space, the frequency and intensity of continuous rain show a pattern of “more in the south and less in the north” and “lighter in the north and heavier in the central and southern regions.” The number of occurrences of continuous rain at all intensity levels follows the order: southern Jiangsu > central Jiangsu > northern Jiangsu. In terms of typical years, the intensity of continuous rain in the Lixiahe region of Jiangsu is the strongest in 2003, 2015, and 2020; the intensity is relatively strong in the north-central part of the area between the Yangtze and Huaihe Rivers in 2003, 2006, and 2012; and the intensity is relatively strong in the central part of southern Jiangsu in 2003, 2015, and 2020. In actual production, focus should be placed on the frequent and severe occurrence regions and periods of continuous rain during the summer harvest and planting period, so as to scientifically prevent farmland waterlogging, optimise the allocation of agricultural machinery and equipment, and rationally achieve risk transfer.