摘要
采用PV-θ阻塞高压指数检索了1950-2008年影响中国天气关键地区的阻塞高压,并分析了这些关键区阻塞高压的气候特征.结果发现:三个关键区中,乌拉尔山地区的年均阻塞频率最高,而鄂霍次克海地区最低.三个阻塞地区阻塞高压的季节变化也不相同,乌拉尔山地区的年均阻塞频率在5-9月较低,在全年的其他月份较高;贝加尔湖地区年均阻塞频率在秋冬高而春夏低;鄂霍次克海地区夏季年均阻塞频率最高.另外,1950-2008年乌拉尔山、贝加尔湖地区以及三个地区总的阻塞高压次数和天数都有明显的线性增加趋势,而鄂霍茨克海地区阻塞高压次数和天数虽然也有增加趋势,但趋势并不显著.Morlet小波分析结果显示近59年来,三个关键区总的和乌拉尔山阻塞高压活动(次数和天数)都存在2年和4年的显著性周期,贝加尔湖阻塞高压次数存在4～5年的显著性周期,鄂霍茨克海地区阻塞高压次数存在6～8年的显著性周期,这两个地区阻塞高压天数无明显的周期性特征.此外,发现中国的主要气象灾害中,旱灾和寒潮灾害多与乌拉尔山阻塞高压活动有关,雨涝灾害主要受乌拉尔山和鄂霍茨克海地区阻塞高压活动影响,而夏季低温和低温雨雪冰冻灾害则与乌拉尔山和贝加尔湖地区阻塞高压活动有密切关系.
The PV-θblocking index was used to search for the blocking highs in the key regions of China during 1950-2008 and the statistical characteristics of blocking highs in the regions which are highly related to the weather of China were analyzed.The results show that the annual blocking frequency of the Ural is the highest in three key regions of China,while that of the Okhotsk is the lowest.The seasonal variations of the blocking highs of the three regions are different from each other.In the Ural,the annual blocking frequency is lowest in May-September and higher in other months.In the Baikal,the annual blocking frequency is higher in autumn and winter and lower in spring and summer.In the Okhotsk,the annual blocking frequency is highest in summer.The annual blocking frequency of the Eurasia moves to the east during June-August. Against the background of global warming,during 1950-2008,the blocking frequency/days increased linearly and significantly in Ural,Baikal and all of the three regions,and the trend of the blocking frequency/days in the Okhotsk were also ascending,but not so significantly.The period analysis by using Morlet wavelet method shows that in recent 59 years,there have been periods of 2 years and 4 years of the blocking activity （including frequency and days） of the total and Ural,but they were distributed in the different decades.The blocking frequency changed with a period of 4～5 years in the Baikal and 6～8 years in the Okhotsk,while the blocking days of these two regions changed without a significant period.According to the statistical results in this paper and those of existing studies,major meteorological disasters such as drought and cold wave are mainly related to blocking highs in the Ural,while waterlogs are influenced by the blocking highs in the Ural and Okhotsk;low temperature in summer and destructive weather including snowfall and anomalous freezing in early 2008 were mostly related to the blocking highs in the Ural and Baikal.
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
2010年第3期47-55,共9页
Journal of Lanzhou University(Natural Sciences)
基金
科技部国家科技支撑计划项目(2007BAC29B03
2008BAC40B04
2009BAC53B02)
国家公益性行业(气象)科研专项(GYHY(QX)2007-6-1)
关键词
PV-θ指数
阻塞高压
气象灾害
PV-θ blocking index
blocking high
meteorological disaster
