摘要
以长江中下游地区8个代表性站点1470年～2000年的旱涝等级资料和1951年～2000年5～9月的器测降水量数据为基础,采用EOF、滑动t检验、小波分析等统计技术,对1470年～2000年长江中下游地区干湿演变的时空特征进行了分析.结果表明:(1)旱涝等级资料能够准确表达该区域干湿演变的时空特征;(2)前3个主要模态——全区一致、东西相反、南北相反,基本上反映了该区域干湿变化的主要特征,其中第一模态解释了42.3%的方差;(3)在30年的时间尺度上,区域干湿突变均出现在1850s以前,1550s、1740s,1820s,1837s由干转湿,1620s、1520s和1850s由湿转干,近50a是过去500a中年际气候变率最大的时段;(4)干湿演变的主要周期是117a、40a、30a、18a、5a和2～3a,除了18年和2～3a的周期震荡强弱变化不明显外,其余的周期信号强弱均在18世纪温暖时段前后出现了明显变化.这也意味着,19世纪的寒冷时段并非是17世纪寒冷时段的循环再现,这两个寒冷时段存在着一定的差异.
Using the Dryness/wetness grads covering the period of 1470-2000 and instrumental measured precipitation from May to September during 1951 to 2000 from eight stations, with the methods of EOF, moving-ttest and wavelet analysis, we analyzed spatial and temporal characters of the dryness/wetness variations in the lower-middle reaches of the Yangtze River. The results show （1） the dryness/wetness grades could accurately reveal the spatial and temporal characters of dryness/wetness variations in the study area; （2） the first three modes which are featured by accordant all over the region, contrary in west-east and in north-south, indicate the main spatial patterns of the dryness/wetness variation, and the first mode accounts for 42.3% of whole variance; （3） at the 30-year scale, the abrupt changes of dryness/wetness occurred before 1850s, conversions from dry condition to wet condition occurred in 1550s, 1740s, 1820s and 1837s and conversions from wet condition to dry condition occurred in 1620s, 1520s and 1850s; the greatest variability occurred in the past 50 years; （4） the dryness/wetness variations had the significant cycles of 117-year, 40-year, 30-year, 18-year, 5-year and 2-3-year; excluding the cycles of 18-year and 2-3-year, other＇s amplitude changed evidently through the 18^th century. It may be implicated that the 19^th century was not the copy of the 17^th, though both of centuries were featured by cold condition.
出处
《华中师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2012年第2期245-249,共5页
Journal of Central China Normal University：Natural Sciences
基金
全球变化研究国家重大科学研究计划项目(2010CB950102)
国家自然科学基金项目(41001122
41071069)
湖北省自然科学基金项目(2010CDB05102)
教育部人文社科基金项目(10YJC790121)
湖北省教育厅基金项目(2011jyq168)
关键词
长江中下游
干湿变化
小冰期
小波分析
the middle-lower reaches of Yangtze River
dryness/wetness variations
the Little Ice Age
Wavelet analysis
