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运用洪涝灾害风险度评估模型对华南地区晚稻生产和生育期的洪涝灾害风险度及其时空差异进行了评价和预测。结果表明:华南地区晚稻洪涝风险度分布大致呈东南向西北递减的特点,东南沿海地区风险度最高,中部地区居中,而桂北地区则最低,其中东南沿海地区风险度是桂北地区的1.4~2倍;从生育期来看,播种至拔节期的降水致灾效应在增加,这主要是受华南后汛期热带气旋降水强度增加的影响,而拔节至成熟期则在减少,但总体上近30年来华南地区晚稻洪涝风险度有逐渐减少的趋势,风险度的变化过程在20世纪90年代末期有明显的突变现象,此后风险度下降最为显著,下降速度达0.277 10 a-1;华南地区晚稻洪涝风险度的变化速度有明显的区域差异性和过渡性,沿海地区在增加,尤其以珠江三角洲平原和潮汕平原增加最为显著,增加速度达0.10 10 a-1以上,内陆山区在减少,华南西部地区减少速度在0.05 10 a-1以上,这主要是地形过渡带作用的结果。由此可见,华南晚稻洪涝灾害风险的关键时期是播种至拔节期,重点关注区域是东南沿海地区。
The flood risk assessment model was applied to evaluate the flood risk and the spatial and temporal variability of late rice production and growth period in South China. The results show that the distribution of risk of late rice flood in South China is roughly the same as that of the northeast to the northwest, with the highest risk in the southeast coastal area, the middle in the central area, and the lowest in the northern Guangxi. The risk in the southeast coastal area is 1.4 ~ 2 times. From the growth period, the catastrophic effects of precipitation from sowing to jointing stage are increasing, which is mainly affected by the increase of precipitation intensity of tropical cyclone in the post-flood season in South China, but decreasing from jointing to maturity, but generally it is nearly 30 The risk of late rice floods in South China tended to decrease gradually in recent years, and the change of risk degree in the late 1990s showed obvious abrupt changes. The risk decreased most significantly thereafter, with a decreasing rate of 0.277 10 a-1. The floods of late rice in southern China The rate of change in risk has obvious regional differences and transitionalities. Coastal areas are increasing, especially in the Pearl River Delta Plain and Chaoshan Plain, with the increasing speed reaching over 0.10 10 a-1, the inland mountains decreasing, and the western South China The regional reduction rate is above 0.05 10 a-1, which is mainly the result of the effect of the terrain transitional zone. Thus, the critical period for the flood risk of late rice in South China is from sowing to jointing and the key area of concern is the southeastern coastal areas.