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1.
用一个有外强迫的、简单的动力系统研究气候系统中的准两年振荡(平均周期长度比两年稍长或稍短的准周期振荡)。结果显示，准两年周期性源于该系统对于受H年周期调制的季节强迫的非线性响应。当系统的非线性固定时，准两年震荡的周期长度和振幅随季节变化的强度和太阳活动11年周期变化的强度而变化。这可能是造成气候中准两年震荡的性质有的空变化的原因之一。 相似文献
2.
《广东气象》2020,(3)
应用功率谱、Morlet小波变换和Butterworth带通滤波处理等方法,对1954—2018年台山站的年降水序列和逐日降水序列数据进行多尺度振荡特征分析。研究表明:台山站年降水量存在11～13、准4、准25年的周期振荡,前汛期降水量存在准13、2～5年的周期振荡,后汛期降水量存在7～8、准20、3～4、准11年的周期振荡。台山站逐日降水振荡基本表现为天气尺度振荡、准单周振荡、准双周振荡、季节内振荡和季节变化振荡等5种尺度,季节内及以下尺度振荡强度相当,季节变化振荡强度较弱。5种时间尺度的标准差,天气尺度最大,季节变化尺度最小,除季节变化振荡外均呈现出周期性循环特征。在汛期雨量偏少年,逐日降水较易呈现出准单周振荡和天气尺度振荡,而汛期雨量偏多年较易呈现出准双周振荡。 相似文献
3.
罗哲贤 《Acta Meteorologica Sinica》1993,51(3):266-273
本文将年变周期和非年变周期热力强迫项引进正压涡度方程,用方程的截谱形式实施了几十组时间长度为100年的数值积分,研究了非年变周期热力强迫和大气内部动力过程共同激发的大尺度流型的年际变化问题。在一定的参数集合,当非年变外源强迫的振荡周期与大气内部动力过程单独激发出来的振荡的周期相同时,流型年际振动的振幅明显加大,振动的周期则为倍化。在另外的参数集合,随着非年变强迫参数的渐变,流型年际变化的幅度显示出清楚的突变以及其它富有非线性特色的行为。 相似文献
4.
本文基于高原季风指数和高原涡数据集,利用小波分析等统计方法对高原季风和高原低涡的气候特征进行了统计分析,并探究了两者之间的关系,主要结果有:(1)高原季风夏强冬弱,高原季风的准4年、准6年周期振荡的特征十分明显。(2)30年来高原低涡平均每年生成64.2个,其中有51.2个是暖性高原低涡。高原低涡的强度季节内呈正态分布,高原低涡的生成频数的季节内变化有明显的周期振荡特征。(3)高原季风的周期振荡特征在季节尺度和年际尺度上与高原低涡气候特征有一定的相关性,准4年与准6年周期振荡特征十分明显。通过相关概率统计:高原季风的建立时间与强度都与高原低涡的气候特征有一定的正负相关。 相似文献
5.
外强迫对热带季节内振荡影响的模拟研究 总被引：5，自引：2，他引：3
应用经过修改的NCAR CCM3模式和CAM2模式进行的数值实验结果以及NCEP的GFS模式的输出结果讨论了海温等外强迫作用对热带季节内振荡的影响.结果表明,热带季节内振荡是热带大气固有的内部变率.它是由大气内部过程的相互作用决定的.但外强迫对热带季节内振荡的强度、传播方向等有明显的影响.当外强迫没有变化时,模式可以模拟出与观测近似的低频振荡.当作为外强迫的海温和太阳辐射有年内季节变化时,模式模拟的季节内振荡则明显减弱.当海温与辐射不仅有季节变化而且有年际变化时,模式模拟的季节内振荡会进一步减弱.具有长周期的外强迫还会削弱季节内振荡中东移波动的能量而增加静止波的强度.在与海洋模式耦合的状态下,模式不受来自海洋的外强迫影响,而是与海洋构成一个耦合系统,可以产生最强的季节内振荡. 相似文献
6.
近十五年全球臭氧变化 总被引：16，自引：1，他引：15
利用卫星观测臭氧总含量ＴＯＭＳ（第７版）资料,在剔除季节变化后对全球６０°Ｓ－６０°Ｎ范围首先进行了沿纬度分布的线性趋势和周期分析。结果表明：自本世纪７０年代末,各纬带上的臭氧总量都呈下降趋势,强度随纬度升高而加剧,并发现总体上北半球臭氧的下降趋势较南半球更加明显;同时证实了准两年振荡是臭氧变化中除年周期外最显著的周期。并对臭氧变化中的准两年振荡作了遥相关分析;发现准两年振荡在强度和位相上基本呈纬向分布并主要表现出赤道对称的特征。１３５～１７０°Ｅ地区臭氧总量变化所表现出的不同于其它地区的原因可能是这一地区常年频繁出现的对流活动;而臭氧总量下降趋势表现出的北半球同纬度地区均大于南半球的南北半球差异可能是由两半球人类活动的差异引起 相似文献
7.
8.
中国东部夏季降水的准两年周期振荡及其成因 总被引：31，自引：13，他引：18
应用中国160测站降水资料和ERA-40再分析资料以及EOF和熵谱分析方法,分析了中国夏季(6～8月)降水和东亚水汽输送通量的年际变化,表明中国(特别是华南、长江流域和淮河流域以及华北等地区)夏季降水具有2～3 a周期变化特征,即准两年周期的振荡特征,并表明中国降水的这种周期振荡与东亚上空夏季风水汽输送通量的准两年周期振荡密切相关;并且,还利用NCEP/NCAR的海表温度和日本气象厅的沿137°E海温剖面观测资料,分析了热带西太平洋表层与次表层海温的年际变化,揭示了热带西太平洋热力状态的变化也有显著的准两年周期的变化特征.作者利用相关和集成分析来讨论热带西太平洋热状态的准两年周期振荡对中国夏季降水和东亚水汽输送的影响,表明了热带西太平洋海温的准两年周期振荡对东亚夏季风及其所驱动的水汽输送都有很大影响.此外,作者还利用东亚/太平洋型(EAP型)遥相关理论,简单地讨论了热带西太平洋热力状态的准两年周期振荡影响中国夏季风降水准两年周期变化的物理机制. 相似文献
9.
应用非线性振荡理论研究云南局地气温的演变规律 总被引：4，自引：3，他引：1
将描述局地气温变化的非线性振荡方程应用到云南省17个测站局地气温演变研究中,根据各测站1958年1月—2000年12月逐旬气温距平资料和反演理论获得具体描述各测站局地气温变化的非线性振荡方程。以经典非线性振荡理论为依据,研究了云南省17个测站的局地气温演变规律。结果表明,云南局地气温系统是弱的非线性系统;其演变的固有周期大致在6～10旬之间;在无外源强迫的条件下,云南局地气温振幅随时间增加总是衰减;考虑外源强迫的作用后,云南局地气温系统在其演变过程中只随外源强迫的振荡而振荡。应用反演获得的描述各测站局地气温变化的有外源强迫非线性振荡方程做出未来云南局地气温演变趋势预报,其平均预报准确率约为78．9％。说明该模型具有良好的预报能力和预报稳定性。 相似文献
10.
《高原气象》2015,(5)
基于中国东南部5个百年站点年气温序列和3套全球表面温度资料(HadCRUT3、GISSTEMP、20CR再分析资料),采用处理非线性、非平稳时间序列的新方法—集合经验模态分解(Ensemble Empirical Mode Decomposition,EEMD),分析了以上海为代表的中国东南部5个站点1873-2011年气温演变的多时间尺度特征,并讨论了多时间尺度影响的全球一致性。结果表明,1873-2011年期间,中国东南部百年站点的年温度演变呈现年际、年代际、多年代际多个时间尺度的准周期变化和长期上升趋势。准64年周期的多年代际振荡和上升趋势分量对长期气温变化均有重要贡献。长期上升趋势分量在100年以上的观测温度变化趋势中占主要贡献,但准64年周期振荡对近50年观测温度变化趋势的贡献要大于上升趋势分量。百余年期间两个明显升温阶段(20世纪30-40年代和20世纪90年代至21世纪初)的形成与准64年周期的多年代际变化的相关关系最为显著,而长期趋势和6~16年的年际—年代际变化对高温期的形成也有一定贡献。准64年周期的多年代际振荡对百余年温度变化趋势的阶段性转变起重要作用。中国东南部百年站点温度演变的多时间尺度特征具有全球性。准64年周期振荡对北半球温度趋势演变也有重要贡献,且北半球温度准64年周期振荡与百年站点温度变化速率的关系也较其长期升温趋势更为密切。北大西洋多年代际振荡对百年站点温度准64年周期振荡及其全球一致性有调节作用。 相似文献
11.
S. A. Sitnov 《Climate Dynamics》2009,32(1):1-17
Using the longest and most reliable ozonesonde data sets grouped for four regions (Japan, Europe, as well as temperate and
polar latitudes of Canada) the comparative analysis of regional responses of ozone, temperature, horizontal wind, tropopause
and surface pressure on the equatorial quasi-biennial oscillation (QBO effects), manifesting in opposite phases of the 11-year
solar cycle (11-yr SC) was carried out. The impact of solar cycle is found to be the strongest at the Canadian Arctic, near
one of two climatological centres of polar vortex, where in solar maximum conditions the QBO signals in ozone and temperature
have much larger amplitudes, embrace greater range of heights, and are maximized much higher than those in solar minimum conditions.
The strengthening of the temperature QBO effect during solar maxima can explain why correlation between the 11-yr SC and polar
winter stratospheric temperature is reversed in the opposite QBO phases. At the border of polar vortex the 11-yr SC also modulates
the QBO effect in zonal wind, strengthening the quasi-biennial modulation of polar vortex during solar maxima that is associated
with strong negative correlation between stratospheric QBO signals in zonal wind and temperature. Above Japan the QBO effects
of ozone, temperature, and zonal wind, manifesting in solar maxima reveal the downward phase dynamics, reminding similar feature
of the zonal wind in the equatorial stratosphere. Above Europe, the QBO effects in solar maxima reveal more similarity with
those above Japan, while in solar minima with the effects obtained at the Canadian middle-latitude stations. It is revealed
that the 11-yr SC influences regional QBO effects in tropopause height, tropopause temperature and surface pressure. The influence
most distinctly manifest itself in tropopause characteristics above Japan. The results of the accompanying analysis of the
QBO reference time series testify that in the period of 1965–2006 above 50-hPa level the duration of the QBO cycle in solar
maxima is 1–3 months longer than in solar minima. The differences are more distinct at higher levels, but they are diminished
with lengthening of the period. 相似文献
12.
Sergei A. Sitnov 《Climate Dynamics》2009,33(5):591-602
On the basis of total column ozone (TO) data obtained in the period of 1957–2007 at 10 ground-based European stations, characterized
by long and highly reliable measurements, the effects of the quasi-biennial oscillation (QBO) and 11-year solar cycle (11-year
SC), manifesting in TO are investigated. The results of comparative analysis of seasonal differences between different QBO/solar
extremes convincingly demonstrate interrelation between the QBO and 11-year SC effects. It is shown that solar activity modulates
the phase of the QBO effect so that the quasi-biennial TO signals during solar maximum and solar minimum are nearly in opposite
phase. It is also demonstrated that isolated under permanent conditions of solar minimum or solar maximum the QBO effects
in TO have the time scale of about 20 months. Solar modulation of the QBO effect makes the QBO a conductor of the solar cycle
impact on TO over Europe. The mechanism of influence of the 11-year SC on the QBO and probably includes its impact on the
QBO amplitude in the equatorial lower stratosphere, mainly through weakening of the equatorial easterlies during solar maximum. 相似文献
13.
Mauro Dall’Amico Lesley J. Gray Karen H. Rosenlof Adam A. Scaife Keith P. Shine Peter A. Stott 《Climate Dynamics》2010,34(2-3):381-398
In most climate simulations used by the Intergovernmental Panel on Climate Change 2007 fourth assessment report, stratospheric processes are only poorly represented. For example, climatological or simple specifications of time-varying ozone concentrations are imposed and the quasi-biennial oscillation (QBO) of equatorial stratospheric zonal wind is absent. Here we investigate the impact of an improved stratospheric representation using two sets of perturbed simulations with the Hadley Centre coupled ocean atmosphere model HadGEM1 with natural and anthropogenic forcings for the 1979–2003 period. In the first set of simulations, the usual zonal mean ozone climatology with superimposed trends is replaced with a time series of observed zonal mean ozone distributions that includes interannual variability associated with the solar cycle, QBO and volcanic eruptions. In addition to this, the second set of perturbed simulations includes a scheme in which the stratospheric zonal wind in the tropics is relaxed to appropriate zonal mean values obtained from the ERA-40 re-analysis, thus forcing a QBO. Both of these changes are applied strictly to the stratosphere only. The improved ozone field results in an improved simulation of the stepwise temperature transitions observed in the lower stratosphere in the aftermath of the two major recent volcanic eruptions. The contribution of the solar cycle signal in the ozone field to this improved representation of the stepwise cooling is discussed. The improved ozone field and also the QBO result in an improved simulation of observed trends, both globally and at tropical latitudes. The Eulerian upwelling in the lower stratosphere in the equatorial region is enhanced by the improved ozone field and is affected by the QBO relaxation, yet neither induces a significant change in the upwelling trend. 相似文献
14.
I. V. Kozlov 《Russian Meteorology and Hydrology》2008,33(6):369-376
A problem of simulation of a stationary random process (SRP) is studied. A computer program is developed for modeling SRP, should the parameters required be estimated beforehand. The programming methods used are well known, but the numerical scheme of modeling the SRP needs some explanations; therefore, it is considered in detail in the article, being its basic subject for consideration, although basic characteristic features of the program are also considered. Examples show how the program is used to simulate the solar cycle and the quasi-biennial oscillation of the solar wind in the equatorial stratosphere (QBO). A distinguishing feature of this work, compared with the previous one, is also simulation of the solar cycle taking into account the variability of the sunspot dispersion. The SRP parameters are estimated for the QBO. It is found that the annual mean wind speed variation behavior is similar to the SRP. 相似文献
15.
通过资料分析发现:夏季50hPa QBO的东、西风位相与华北南部降水及旱涝状况的关系存在显著的阶段性,并明显地受太阳活动11年周期的影响。分析表明,50年代以来,太阳活动11年周期双周内,平流层夏季50hPa QBO西风位相年华北南部降水偏多,东风位相年降水偏少;反之,在单周内东风位相年降水偏多,西风位相年降水偏少。分析还表明,平流层夏季50hPaQBO纬向风强度自身的演变也存在显著的跃变过程,在太阳活动11年周期单周内东风平均强度较双周显著增强。 相似文献
16.
M. P. Souza Echer E. Echer D. J. Nordemann N. R. Rigozo A. Prestes 《Climatic change》2008,87(3-4):489-497
In this work we apply the wavelet transform to the Pelotas (southern Brazil) total annual rainfall series (1894–1995). Classical, wavelet and cross-wavelet analyses were performed in the El Niño Southern Oscillation (ENSO), Quasi-Biennial Oscillation (QBO), sunspot number (Rz) and Pelotas rainfall time series. Classical spectral analysis for Pelotas has shown a large number of short periods – between 2.2–5.6 years (yr) and periods at 8.9, 11.7 and 24.9 yr. Further, we have found that the Pelotas rainfall wavelet spectrum shows the most significant periodicities around 2–8 yr, but they have an intermittent character. Cross-wavelet spectrum showed that: rainfall and QBO series are correlated at 2–3 yr (QBO) scales and this cross-power is continuous along the time series interval; rainfall and SOI have higher cross-power around 4–8 yr, but this signal is sporadic; rainfall and sunspot number (Rz) showed higher cross-power around the 11-yr solar cycle period, but this cross-power is sporadically high and low; finally, the rainfall cross-spectrum with the double sunspot number (Rz22) revealed a high cross-power around 20–22 yr which is more persistent in duration, compared to the 11-yr period. These wavelet results are compared with classical spectral analysis and with previous work results. We concluded that the phenomenon that influences most of Pelotas rainfall variability is ENSO, but only a minor part of the variance (～30%) can be described by a simple multi-linear dependence on solar/ENSO/QBO phenomena, this result could imply that non-linear coupling among sun and internal climatic variability (QBO, ENSO) has an important role in the local/regional climate variations. 相似文献
17.
C. A. Varotsos N. A. Dris D. N. Asimakopoulos C. Cartalis 《Theoretical and Applied Climatology》1992,46(1):27-32
Summary The behaviour of the 10.7 cm solar flux, surface air temperature and sea surface pressure are discussed on the basis of the 11-year solar cycle and the Quasi-Biennial Oscillation (QBO) over Greece. In this respect a strong negative correlation was identified between the 11-year solar cycle and the sea surface pressure during the winter west phase years of the QBO, while a similar correlation was found between the sea surface pressure differences estimated between stations located in northern and southern regions of Greece, and the 11-year solar cycle. On the contrary, for the same QBO period, a strong positive correlation was observed between the 11-year cycle and the surface air temperature in Greece in agreement with recently published results. Considering the east phase QBO years, no correlation was identified between the 10.7 cm solar flux and the sea surface pressure and surface air temperature over Greece.With 7 Figures 相似文献
18.
E. A. Titova I. L. Karol A. M. Shalamyanskii L. P. Klyagina A. A. Solomatnikova 《Russian Meteorology and Hydrology》2009,34(7):442-453
The analysis of external factors, which are most significant for the formation of the monthly mean total ozone (TO) field and ozone transport over the Russian Federation, based on observation data obtained from about 30 ground-based stations of the ozonometric network averaged over a year, December through March and June through August, over five climatic regions, is considered. Performed spectrum and discriminant analysis allowed obtaining quantitative estimates of the impact of the Arctic Oscillation, deviation of the winter temperature of the lower polar stratosphere, quasi-biennial oscillations (QBO), 11-year solar cycle, El Niño-Southern Oscillation (ENSO) on the TO and to assess the regional differences in the effects of these factors. In December–March, in the years with a negative Arctic Oscillation phase, warm stratosphere, and the easterly QBO phase (QBO-E), the ozone content increases significantly relative to the opposite phases of oscillations on average by 35, 28, and 26 Dobson units (DU), respectively. The spectra, similar to the discriminant function, demonstrate strong influence of the 11-year solar cycle and QBO on the TO even in the summer months, while the QBO is more pronounced in the eastern part of the Russian Federation. The ENSO effect was not singled out against the general “noisy” background of the cold six-month period, when many atmospheric processes become active: however, during the summer months, in warm periods of the ENSO, the TO, at the 97% significance level, increases over most of the Russian area. The rest of the obtained results are significant at the 95–99.9% level. 相似文献
19.
20.
A nonlinear principal component analysis (NLPCA) is applied to a set of monthly mean time series from January 1956 to December 2007 consisting of the Arctic oscillation (AO) index derived from 1,000-hPa geopotential height anomalies poleward of 20°N latitude and the zonal winds observed at seven pressure levels between 10 and 70?hPa in the equatorial stratosphere to investigate the relation of the AO with the quasi-biennial oscillation (QBO). The NLPCA is conducted using a new, compact neural network model. The NLPCA modeling of the dataset of the AO index and QBO winds offers a clear picture of the relation between the two oscillations. In particular, the phase of covariation of the oscillations defined by the two nonlinear principal components of the dataset progresses with a predominant 28.4-month periodicity. This predominant cycle is modulated by an 11-year cycle. The variation of the AO index with the QBO phase also shows that the average AO index is positive when the westerly QBO phase descends past 30?hPa and, conversely, the average AO index is negative when the easterly QBO phase descends past 30?hPa. This relationship is evident during the boreal cold season from November to April but non-existent during the boreal warm season from May to October. 相似文献