摘要
本文利用Logistic模型,推导出描述均值突变的分段函数,用该函数对可能存在突变的时间序列进行拟合,并结合概率分布理论,确定突变幅度最大的时段即为发生突变的过程,由此确定并分析序列中突变的开始时刻、突变幅度、突变变率、突变持续时间、系统不稳定特性等参数。对全球500hPa温度场单点时间序列的突变持续过程展开研究:(1)对突变过程的开始时刻进行统计,发现1956～1959、1970～1979、1986～1994、1994～2004年开始的突变所占比重较大,几次突变过程中,平均来看除了1986～1994年开始的突变表现为降温,其余几次突变均表现为增温;并且每次突变时,增温幅度比较大的突变,其变率也较大;(2)从突变先后的空间分布上看,1956～1959、1970～1979年检测到发生突变的格点在海洋上空的突变偏早、欧亚大陆上空偏晚,而1986～1994和1994～2004年突变期间这一情况正好相反;(3)针对每次突变过程中的突变幅度,低纬度区域温度发生突变的变化幅度较小、高纬度区域较大;(4)对突变持续时间的检测结果表明,在全球增暖背景下,完成一次突变的持续时间正在逐渐变短;(5)当系统突变正在进行时,系统的不稳定性较强。
In this paper, we fit the time series, which likely has abrupt change processes （ACP）, with piecewise function deducing for describing the mean abrupt change from the logistic model. Thus combined with the theory of probability distribution formed the basis for considering the process in which abrupt change amplitude is maximum, as is the ACP. The parameters reflecting the beginning moment of the abrupt change, abrupt change amplitude, abrupt change rate, persistence time, and instability are determined and analyzed. By testing the time series in a 500 hPa temperature field during the period 1948-2012, we determine the following results： （1） Abrupt changes started in 1956-1959, 1970-1979, 1986-1994, and 1994-2004. We considered more probabilities by testing the start moment of the ACP. In these changes,the temperatures of all changes in the means show increases except for that in 1986-1994, and the rate increases if the abrupt change amplitude is large. （2） In spatial distribution of the abrupt change moment, the moment of the grid points in which the abrupt change occurred in 1956-1959 and 1970-1979 above the sea occurred earlier than that in the grid points above Eurasia, whereas the abrupt changes in 1986-1994 and in 1994-2004 show opposite behavior. （3） The abrupt change amplitude of temperature occurring in low latitudes is lower than that occurring in high latitudes. （4） Under the context of global warming, the statistics distribution of the persistence time shows that an increasing number of grid points require shore time to complete an abrupt change. （5） During the abrupt change process, the instability of the system was enhanced significantly.
出处
《大气科学》
CSCD
北大核心
2014年第5期861-873,共13页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金项目41175067
国家重点基础研究发展计划项目2012CB955901
2013CB430204
关键词
气候突变
500
hPa温度场
突变过程
持续时间
不稳定性
Abrupt climate change
500 hPa temperature field
Abrupt change process
Persist time
Instability
