气候变化背景下广东双季稻种植的洪涝灾害风险评估

Flood Risk Assessment of Double-Cropping Rice Cultivation in Guangdong Province under Climate Change

关键词:  洪涝灾害风险度  双季稻  气候变化  广东省

Key words:  flood risk  double-cropping rice  climate change  Guangdong Province

摘要:

建立洪涝灾害风险度评估模型，对广东双季稻生产和生育期的洪涝灾害风险度的时空特征进行分析和评估。结果表明：广东双季稻洪涝灾害风险度分布大致呈中部向东西两翼递减的特点，北江流域和漠阳江流域最高，而粤西地区和粤东沿海最低，其中粤北地区风险度是东西两翼地区的 1.5~2.0倍；晚稻洪涝灾害风险高于早稻，从生育期来看，早稻移栽-分蘖期、分蘖-拔节期和晚稻播种-三叶、三叶-移栽期洪涝灾害风险度较高、特别严重的洪涝灾害频率较多；近 10 年来广东双季稻洪涝灾害风险度有所增加，特别严重的洪涝灾害频率增多，尤其以早稻播种期至移栽期以及晚稻拔节期至成熟期增多最为明显，而严重洪涝灾害等级及以下频率减少；广东双季稻洪涝风险度的变化速度有明显的区域差异性，珠江三角洲平原增加趋势最为显著，东江流域和韩江流域呈降低趋势。未来广东双季稻洪涝灾害风险总体呈上升趋势，特别严重的洪涝灾害呈多发趋势，其时空集中度更高，洪涝灾害风险的高发期是双季稻播种至拔节期，重点关注区域是广东中部地区。

Abstract:

The flood disaster risk assessment model was established to analyze and evaluate the spatio- temporal characteristics of flood disaster risks during both cultivation and growth periods of double- cropping rice in Guangdong Province. The results indicate that the flood disaster risk of double cropping rice cultivation in Guangdong generally decreases from the central region toward the eastern and western wings, with the highest risks in the Beijiang River Basin and Moyangjiang River Basin and the lowest in western and eastern coastal Guangdong. The risks in the northern region of Guangdong are 1.5 to 2.0 times higher than those in the eastern and western wings. The results also indicate that the flood disaster risk for late rice is higher than for early rice. In terms of growth stages, the flood risk is high during the transplanting-tillering and tillering-jointing stages of the early rice, as well as the sowing-three-leaf and three-leaf-transplanting stages of the late rice, with notably higher frequency of particularly severe flood disasters. Over the past decade, the flood risks for double-cropping rice in Guangdong have increased, with an increase in the frequency of extremely severe flood disasters, particularly notable during the early rice sowing-to-transplanting stage and the late rice jointing-to-maturity stage, while the frequencies of severe- level and less severe floods have decreased. Moreover, the changing rates of flood risk for double-cropping rice in Guangdong exhibit pronounced regional variations: the Pearl River Delta Plain displays the most significant increasing trend, whereas the Dongjiang and Hanjiang River Basins show a decreasing trend. In the future, the overall trend of flood disaster risks for double cropping rice in Guangdong is expected to rise, with more frequent occurrences of extremely severe flood disasters, exhibiting higher spatiotemporal concentration. The highest flood risk for double-cropping rice systems is observed during the critical growth period from sowing to jointing, with regions in central Guangdong being the key areas of highly concern.