气候变化背景下中国南方地区季节性干旱特征与适应Ⅴ.南方地区季节性干旱特征分区和评述

Characteristics and adaptation of seasonal drought in southern China under the background of climate change. Ⅴ. Seasonal drought characteristics division and assessment in southern China

在干旱特征研究的基础上开展季节性干旱分类分区,可为不同干旱区域应对全球气候变化、制定抗旱减灾对策和防控技术提供理论依据.以国家标准中的气象干旱、农业干旱指标为主要依据,利用南方地区268个气象台站1959—2008年的气候资料,在分析南方地区季节性干旱的气候背景和分布特征的基础上,采用综合因子与主导因子相结合方法、逐级指标筛选法,综合灾害分析和聚类分析方法,对季节性干旱进行3级分区.一级分区以年干燥度和季干燥度为主要指标,以年尺度和主要作物生长季的降水量为辅助指标,将南方区域分为半干旱区、半湿润区、湿润区和极湿润区4个一级区;在此基础上再划分为川滇高原山地温凉半干旱区,江北温暖半湿润区、华南暖热半湿润区和西南高原温凉半湿润区3个半湿润区,长江流域温热湿润区、华南暖热湿润区和西南山地温暖湿润区3个湿润区,以及华南暖热极湿润区和江南西南山区温凉极湿润区2个极湿润区,共9个二级干旱分区.最后基于多个干旱指标的干旱频率和干旱强度,将南方区域分成29个三级干旱区.在分区基础上对不同季节性干旱特征分区分布情况、干旱特点及对农业生产影响进行评述,并提出了防旱避灾措施.

Zoning seasonal drought based on the study of drought characteristics can provide theo- retical basis for formulating drought mitigation plans and improving disaster reduction technologies in different arid zones under global climate change. Based on the National standard of meteorological drought indices and agricultural drought indices and the 1959-2008 meteorological data from 268 meteorological stations in southern China, this paper analyzed the climatic background and distribu- tion characteristics of seasonal drought in southern China, and made a three-level division of sea- sonal drought in this region by the methods of combining comprehensive factors and main factors, stepwise screening indices, comprehensive disaster analysis, and clustering analysis. The first-level division was with the annual aridity index and seasonal aridity index as the main indices and with the precipitation during entire year and main crop growing season as the auxiliary indices, dividing the southern China into four primary zones, includin~ semi-arid zone, sub-humid zone, humid zone, and super-humid zone. On this basis, the four primary zones were subdivided into nine sec- ond-level zones, including one semi-arid area-temperate-cold semi-arid hilly area in Sichuan-Yun- nan Plateau, three sub-humid areas of warm sub-humid area in the north of the Yangtze River, warm-tropical sub-humid area in South China, and temperate-cold sub-humid plateau area in South- west China, three humid areas of temperate-tropical humid area in the Yangtze River Basin, warm- tropical humid area in South China, and warm humid hilly area in Southwest China, and two super- humid areas of warm-tropical super-humid area in South China and temperate-cold super-humid hill- y area in the south of the Yangtze River and Southwest China. According to the frequency and in- tensity of multiple drought indices, the second-level zones were further divided into 29 third-level zones. The distribution of each seasonal drought zone was illustrated, and the zonal drought charac- teristics and their impacts on the agricultural production were assessed. Accordingly, the drought prevention measures were proposed.