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Collective behaviour of climate indices in the North Pacific airben sea system and its potential relationships with decadal climate changes 下载免费PDF全文
A climate network of six climate indices of the North Pacific air-sea system is constructed during the period of 1948-2009. In order to find out the inherent relationship between the intrinsic mechanism of climate index network and the important climate shift, the synchronization behaviour and the coupling behaviour of these indices are investigated. Results indicate that climate network synchronization happened around the beginning of the 1960s, in the middle of the 1970s and at the beginnings of the 1990s and the 2000s separately. These synchronization states were always followed by the decrease of the coupling coefficient. Each synchronization of the network was well associated with the abrupt phase or trend changes of annually accumulated abnormal values of North Pacific sea-surface temperature and 500-hPa height, among which the one that happened in the middle of the 1970s is the most noticeable climate shift. We can also obtain this mysterious shift from the first mode of the empirical orthogonal function of six indices. That is to say, abrupt climate shift in North Pacific air-sea system is not only shown by the phase or trend changes of climate indices, but also might be indicated by the synchronizing and the coupling of climate indices. Furthermore, at the turning point of 1975, there are also abrupt correlation changes in the yearly mode of spatial degree distribution of the sea surface temperature and 500-hPa height in the region of the North Pacific, which further proves the probability of climate index synchronization and coupling shift in air-sea systems. 相似文献
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A simple heuristic model of coupled decadal ocean-atmosphere modes in middle latitudes is developed. Previous studies have treated atmospheric intrinsic variability as a linear stochastic process modified by a deterministic coupling to the ocean. The present paper takes an alternative view: based on observational, as well as process modeling results, it represents this variability in terms of irregular transitions between two anomalously persistent, high-latitude and low-latitude jet-stream states. Atmospheric behavior is thus governed by an equation analogous to that describing the trajectory of a particle in a double-well potential, subject to stochastic forcing. Oceanic adjustment to a positional shift in the atmospheric jet involves persistent circulation anomalies maintained by the action of baroclinic eddies; this process is parameterized in the model as a delayed oceanic response. The associated sea-surface temperature anomalies provide heat fluxes that affect atmospheric circulation by modifying the shape of the double-well potential. If the latter coupling is strong enough, the model’s spectrum exhibits a peak at a periodicity related to the ocean’s eddy-driven adjustment time. A nearly analytical approximation of the coupled model is used to study the sensitivity of this behavior to key model parameters. 相似文献
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Nonlinear evolution characteristics of the climate system on the interdecadal-centennial timescale 下载免费PDF全文
To better understand the physical mechanism of the climate change on interdecadal-centennial timescale, this paper focuses on analysing and modelling the evolution characteristics of the climate change. The method of wavelet transform is used to pick out the interdecadal timescale
oscillations from long-term instrumental observations, natural proxy records, and modelling series. The modelling series derived from the most simplified nonlinear climatic model are used to identify whether modifications are concerned with some forcings such as the solar radiation on the climate system. The results show that two major oscillations exist in various observations and model series, namely the 20--30a and the 60--70a timescale respectively, and these quasi-periodicities are
modulated with time. Further, modelling results suggest that the originations of these oscillations are not directly linked with the periodic variation of solar radiations such as the 1-year cycle, the 11-year cycle, and others, but possibly induced by the internal nonlinear effects of the climate system. It seems that the future study on the genesis of the climate change with interdecadal-centennial timescale should focus on the internal nonlinear dynamics in the climate system. 相似文献
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两位气候学家和一位理论物理学家共同荣获2021年诺贝尔物理学奖.诺贝尔物理学奖委员会在背景介绍材料中指出,他们在"理解复杂物理系统领域做出了开创性贡献".相信很多人会对两位气候学家获奖而感到惊讶,物理学奖委员会进一步具体指出,人类活动导致全球变暖这一论断建立在坚实的科学基础之上,两位气候学家获奖是因为他们基于物理原理模... 相似文献
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快速、准确的检测气候突变, 对于我们认识气候系统的变化和对未来气候系统演变趋势的预测有着重要的现实意义和社会经济价值. 本文主要回顾了近年来非线性突变检测技术的主要研究进展及其在实际观测资料中的应用, 其中包括基于气候系统长程相关性的检测方法, 如滑动去趋势波动分析方法、滑动移除去趋势波动分析方法、滑动移除重标极差方法和指纹法等; 以及基于时间序列复杂性的检测方法, 如近似熵方法, Fisher信息和小波Fisher信息等. 此外, 本文还指出发展针对空间场的突变检测技术是未来一个可能的发展方向. 由于空间场所包含的气候系统的演变信息远高于单点时间序列, 空间场的突变检测技术将会使得对气候突变的检测时间大大缩短, 从而使得人们有足够的时间去采取行动, 以便为适应气候突变所带来的新挑战做好准备. 相似文献
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Complex networks have been studied across many fields of science
in recent years. In this paper, we give a brief introduction of
networks, then follow the original works by Tsonis et al
(2004, 2006) starting with data of the surface temperature from 160
Chinese weather observations to investigate the topology of
Chinese climate networks. Results show that the Chinese climate network
exhibits a characteristic of regular, almost fully connected
networks, which means that most nodes in this case have the same number
of links, and so-called super nodes with a very large number of
links do not exist there. In other words, though former results show
that nodes in the extratropical region provide a property of
scale-free networks, they still have other different local fine
structures inside. We also detect the community of the Chinese
climate network by using a Bayesian technique; the effective number
of communities of the Chinese climate network is about four in this
network. More importantly, this technique approaches results in
divisions which have connections with physics and dynamics; the
division into communities may highlight the aspects of the dynamics
of climate variability. 相似文献
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Based on physical backgrounds, the four time series of the Guliya (Tibetan plateau) ice core (GIC) 5180, and three natural factors, i.e. the rotation rate of earth, sunspots, and E1 Nino-Southern Oscillation (ENSO) signals, are decomposed into two hierarchies, i.e. more and less than 10-year hierarchies respectively, and then the running t-test is used to reanalyse the data before and after filtering with the purpose of investigating the contribution of natural factors to the abrupt climate changes in the last one hundred years. The results show that the GIC 5180 evolved with a quasi-period of 7-9 years, and the abrupt climate changes in the early 1960s and in the period from the end of the 1970s to the beginning of the 1980s resulted from the joint effect of the two hierarchies, in other words, the two interdecadal abrupt changes of climate in the last one hundred years were global. The interannual variations of ENSO and sunspots were the important triggering factors for the abrupt climate changes in the last one hundred years. At the same time, the method of Information Transfer (IT) is employed to estimate the contributions of ENSO signals and sunspots activities to the abrupt climate changes, and it is found that the contribution of the interannual variation of ENSO signals is relatively large. 相似文献
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Lyapunov 指数是标志一个系统做规则运动还是混沌运动的一个重要物理量.鉴于此, 本文利用Lyapunov指数研究系统的混沌特性, 研究气候的突变.计算结果表明, 定义法求得的Lyapunov指数是一种可靠的突变检测方法, 无论是理想序列还是实际存在突变的序列, 利用该方法都能准确地找出突变位置; 而利用非线性局部Lyapunov指数的可预报期限从理论上佐证了基于临界慢化现象的气候突变前兆信号的可靠性, 通过计算各个时间段的最大Lyapunov指数能够反映系统的内在性质、研究其混沌特性. 研究结果为该方法在实际观测资料中的广泛应用提供了理论基础.
关键词:
Lyapunov指数
气候突变
前兆信号 相似文献
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近年来, 临界慢化现象在揭示复杂动力系统是否趋向于临界性灾变方面展示了重要潜力. 本文基于临界慢化的理念, 着重研究不同噪声影响下, 气候突变前兆信号出现的时间; 对含有不同噪声的气温观测资料、太平洋年代际振荡指数以及阿留申低压强度资料进行处理, 研究突变的前兆信号. 以20世纪70年代末80年代初这次气候突变为例, 分别计算了表征临界慢化现象的方差和自相关系数. 结果表明, 临界慢化现象出现在具有不同信噪比的资料中, 这表明临界慢化现象可能是气候突变发生前的一个前兆信号, 并且噪声对气候突变前兆信号的检测结果影响较小, 从而论证了临界慢化现象检测突变前兆信号的可靠性, 为该方法在实际观测资料中的广泛应用提供了实验基础. 相似文献
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J.L. Gonzalez E.L. de FariaMarcelo P. Albuquerque Marcio P. Albuquerque 《Physica A》2011,390(4):587-594
The concepts of nonextensive statistics, which has been applied in the study of complex systems, are used to analyze past records of the Earth’s climate. The fluctuations within the record of deuterium content (hence temperature) in the last glacial period appear to follow a q-Gaussian distribution. Analyses of the time-dependent nonadditive entropy indicate transitions between different complexity levels in the data prior to the abrupt change in the system dynamics at the end of the last glaciation. Different fluctuation regimens are evidenced through wavelets analysis. It is also suggested that time-dependent entropy analysis could be useful for indicating the approach to a critical transition of the Earth’s climate for which theoretical models are in many cases not available. 相似文献
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气候系统的非线性、多层次性和非平稳性对气候突变的检测方法提出了较高的要求.基于t检 验将非平稳序列分割为多个不同尺度的自平稳子序列,Bernaola Galvan提出的启发式分割 算法(BG算法),对非平稳时间序列的突变检测效果较好.在BG算法的基础上,通过理想时间 序列验证BG算法处理非平稳时间序列的有效性,并对近2000a北半球树木年轮距平宽度序列 基于不同层次的思想,检测和分析其中包含的各种尺度的气候突变事件,成功地区分不同尺 度的突变.定义的新物理量——突变密度的分析表明,自然因素作用的基础上,人为因素影 响的加剧可能导致近1000a来突变密集段和稀疏段分布失衡,这可能是全球变化的重要表现 之一.
关键词:
气候突变
均值段
突变密度
人为因素
全球变化 相似文献
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近年来, 临界慢化现象在揭示复杂动力系统是否趋向于临界性突变方面展示了重要潜力. 在此基于临界慢化的理念, 对含有不同噪声的中国一级气象地理区划的11大区域的气温观测资料进行处理, 研究气候突变的前兆信号. 首先利用Mann-Kendall (M-K)方法准确的找出各个区域的突变位置, 然后计算了表征临界慢化现象的自相关系数以此寻找气候突变前兆信号, 并研究了不同噪声对气候突变前兆信号的影响. 结果表明, 针对不同的信噪比、不同区域的气温资料在气候突变发生前5–10年均出现了自 相关系数增大的临界慢化现象, 临界慢化现象可能是气候突变发生前的一个前兆信号; 噪声对气候突变前兆信号的检测结果影响较小, 论证了临界慢化现象检测突变前兆信号的可靠性, 为该方法在实际观测资料中的应用提供了实验基础.
关键词:
气候突变
临界慢化
M-K方法
前兆信号 相似文献
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气候变化指数是目前有关气候变化研究领域的前沿课题, 国内外在气候变化研究领域存在着许多具体指数,但关于综合指数的研究却非常少见. 本文将基于温度和降水的单一要素指数的气候变化信息进行综合, 得到一个综合气候变化指数CCI (climate change index)以评估中国近50年来的气候变化及其区域敏感性.指数大小表征气候突变前后极端气候事件的频数之差, 反映该地区应对气候变化的能力,反映该地区对气候变化的敏感性. 通过该指数可以获得多种气候变化的相关信息,从而为更好地应对极端气候事件提供判断依据. 研究结果显示,内蒙古大部、东北中部、云南以及西北中部等地CCI指数较大, 说明这些地区相对于气候突变之前极端气候事件频发. 中国各个省份中的所有站点的CCI指数平均值表明,中国江南和西南东部对气候变化不敏感; 华北和东北地区极端气候事件频发.气候变化在高纬度地区和热带、 亚热带地区表现明显,北方和西南比较敏感,而黄河以南敏感性较弱, 沿海地区由于受季风及台风带来的强降水的影响, CCI指数相对偏大,敏感性较强. 相似文献
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近年来,临界慢化现象在揭示复杂动力系统是否趋于临界性灾变方面展示了重要潜力.基于临界慢化的理念,研究了气候突变的早期预警信号.针对20世纪70年代末80年代初的气候突变,对全国月平均温度资料和太平洋年代际振荡(PDO)指数进行分析,分别计算了表征临界慢化现象的方差和自相关系数.结果表明,气候发生突变前,全国月平均温度和PDO指数都存在明显的临界慢化现象,这表明临界慢化现象可能是气候突变发生前的一个早期信号.将临界慢化理论用于气候突变前兆信号的研究,对深入认识气候突变和捕捉气候突变前兆信号都具有重要的现实意义和科学价值. 相似文献
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Nobuo MIMURA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2013,89(7):281-301
Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society. 相似文献
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目前,大多数统计预测模型均假设时间序列或观测数据是线性和平稳的。然而,自然界的观测资料是非线性和非平稳的,通常很难用这些数学模型预测它们。本文针对这一问题提出了一个新的预测方案,即首先利用经验模态分解方法将非线性/非平稳时间序列平稳化,得到一系列本征模函数(IMF);其次用均生函数模型预测各IMF分量;最后以所有IMF的预测值为新样本对源序列作最优子集回归模型的拟合及预测。结果表明每个IMF,尤其是特征IMF(即特征层次)比源序列有更高的可预测性。该方案为气候预测开辟了一条新的有效途径。 相似文献