摘要
摘要:结合作物生产开展区域干湿演变及其影响因素研究，对农业可持续发展和粮食安全具有重要的科学意义。本文基于西南水稻种植区316个气象站点1961—2015年的观测资料，利用降水量与参考作物蒸散量（ET₀）的比值计算湿润指数，分析近55年西南区域单季稻生长季干湿演变特征；探讨ET₀对主要气候要素的敏感性及主要气候要素对ET₀的贡献率，对西南区域单季稻生长季干湿演变的影响因素展开研究。结果表明：西南区域单季稻生长季的半湿润区主要分布在四川攀西地区南部、云南中部和东北部，其余地区属湿润区。与1961—1990年相比，1991—2015年研究区域内的半湿润区面积增加、湿润区面积减小。近55年来，单季稻生长季内西南区域有40.8%的站点气候变湿，其余地区气候变干。四川盆地东北部、云南东北部由于降水量的增加和ET₀的减少，气候变湿；四川攀西地区由于降水量增加对湿润指数的正效应大于ET₀增加对湿润指数的负效应，气候变湿；重庆南部、贵州北部和西部由于降水量减少对湿润指数的负效应小于ET₀减少对湿润指数的正效应，气候变湿；云南大部由于降水量的减少和ET₀的增加，气候变干；西南其他区域由于降水量减少对湿润指数的负效应大于ET₀减少对湿润指数的正效应，气候变干。西南区域单季稻生长季ET₀随平均气温和相对湿度的增加而减小，而随日照时数和风速的增加而增加，日照时数和风速的显著下降是ET₀减小的主要原因。研究为气候变化背景下降低西南区域单季稻生长季可能的气候风险提供了科学依据。
关键词:西南区域/
单季稻/
湿润指数/
干湿演变/
降水量/
参考作物蒸散量/
气候要素
Abstract:Research on regional dry-wet evolution and its influencing factors during the crop growing season is critical for sustainable agricultural development and food security. In this study, which is based on the daily meteorological data from 316 meteorological stations in the rice-growing area of Southwest China from 1961 to 2015, and on calculation of the ratio of precipitation to reference crop evapotranspiration (ET₀) in a single cropping rice growing season in Southwest China, the characteristics of dry-wet evolution from 1961 to 2015 were analyzed. The sensitivity of ET₀ to the main climatic factors and attribution rates to ET₀ of the main climatic factors were studied, and the factors influencing dry-wet evolution were also discussed. The results showed that the semi-humid climatic regions with a single cropping rice growing season in Southwest China were mainly distributed in the south of Panxi area of Sichuan and the center and northeast of Yunnan, but that the rest of Southwest China comprised humid climatic regions. Compared with 1961-1990, the area of the semi-humid climatic region in Southwest China increased during 1991-2015, while the area of the humid climatic region decreased. During the single cropping rice growing season, 40.8% of the sites in Southwest China became wet from 1961 to 2015, and the rest of the region became dry. The climate became wet in the northeast of Sichuan basin and the northeast of Yunnan because of increasing precipitation and decreasing ET₀. The positive effect caused by the increasing precipitation on the humidity index exceeded the negative effect caused by the increasing ET₀, which resulted in the climate becoming wet in the Panxi area of Sichuan. The positive effect caused by the decreasing ET₀ on the humidity index exceeded the negative effect caused by the decreasing precipitation, which resulted in the climate becoming wet in the south of Chongqing, and in the north and west of Guizhou Province. In contrast, most of Yunnan showed a dry trend with decreasing precipitation and increasing ET₀. The climate became drier in other areas of Southwest China because the negative effect caused by the decreasing precipitation on the humidity index exceeded the positive effect of the decreasing ET₀. During the single cropping rice growing season, the ET₀ decreased with increasing average temperature and relative humidity in Southwest China, but the ET₀ increased with increasing sunshine hours and wind speed. The significant decline in sunshine hours and wind speed in Southwest China was the main reason for the decrease in ET₀. The study provided a scientific basis for reduction of the possible climate risks of the single cropping rice growing season in Southwest China under global climate change.
Key words:Southwest China/
Single cropping rice/
Humid index/
Dry-wet evolution/
Precipitation/
Reference crop evapotranspiration/
Climate factor



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