太阳活动11年周期对气候系统中准两年振荡的影响(英)

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11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时空变化的原因之一。     

NUMERICAL INVESTIGATION OF QBO IN OZONE

In this paper, a two-dimensional primitive equation model, coupling dynamical, radiative andphotochemical processes, is used to simulate the quasi-biennial oscillation (QBO) in ozone. TheQBO in total ozone has been successfully simulated when the forcing of equatorial stratosphericQBO in zonal wind is imposed. The simulated characters of QBO in ozone are in close agreementwith those observed. We further analyzed the mechanism of formation and maintenance of QBO inozone. In the different phases of QBO in equatorial stratospheric wind field, the global circulationhas so great difference that it makes the effects of advection transfer and eddy transfer present aquasi-biennial periodical variation. Chemical effect and dynamical effect are basically out-of-phase.They together form and maintain the QBO in ozone. Total variation rate is a tiny difference of thetwo large amounts. At the lower level of middle-high latitudes, however, it has a phase differenceof about 1-2 months between dynamical and negative chemical effects, where the dynamical effectis comparatively greater. QBO in ozone has no clear counter effects on atmospheric circulation. The experiment resultsshow that the effects of QBO in ozone on temperature field and wind field are very small.     

中国东部夏季降水准两年振荡的主振荡型分析

利用中国160个测站月降水资料和NCEP/NCAR再分析月平均资料,选取中国东部夏季降水准两年振荡(TBO)分量做主振荡型分析(POP)和伴随相关分析(ACP)。结果表明:第一个POP对占东部夏季降水TBO总方差的18.2%,循环周期约为4年。实部为过渡型,振幅在1950年代中期和1980年代初期明显增大,在1980年代中后期到1990年代中期振幅的TBO特征异常显著。虚部为峰值型,在华南东部—长江流域—江淮流域有大范围的正值中心,高值中心位于长江—江淮流域,华南中西部为一负中心。虚部型振幅,1990年代中后期虚部型的振幅有明显加强。海温的伴随相关说明东部夏季降水TBO过渡型与西太平洋海温异常相对应,峰值型与赤道中东太平洋海温异常相对应。850 hPa风场异常、赤道纬向风异常和经向垂直环流异常的伴随相关显示,当POP对处于过渡型(负过渡型)时西太平洋对流旺盛(弱),南海上空有反气旋(气旋)生成。当POP对处于峰值型(负峰值型)时,赤道上Walker环流减弱(加强),经向上Hardly环流位置偏南(北),强度加强(减弱)。总之,中东太平洋海温异常与东部夏季降水TBO的传播有着密切联系,并通过海气相互作用和低纬与中高纬的相互作用来影响中国东部夏季降水TBO的传播,南北半球环流的相互作用也需要进一步探讨。     

平流层大气环流的典型系统及变化特征综述

随着大气探测技术以及计算机性能的不断提高,近年来平流层探测数据日渐丰富,中层大气模式也得到了快速发展,平流层中一些重要的物理、化学以及动力过程得以深入研究,对平流层大气环流的认识也进一步加深。本文分析了平流层准2 a振荡（Quasi-Biennial Oscillation,QBO）、平流层残余（Brewer-Dobson,BD）环流和平流层极地环流等主要的平流层大气环流系统和信号的气候态特征、形成机制、年际变率以及长期趋势等,阐述了它们的主要影响因子和过程,讨论并展望了与平流层环流有关的一些主要科学问题。     

近50年中国华南雨涝变化特征分析

对流层大气环流和气象气候要素具有明显的准两年周期振荡,被称为Tropospheric (Quasi-)Biennial Oscillation(TBO)。综述了各种TBO现象及其机理研究。目前发现对流层中温度、气压、风场、降水以及季风、副高等系统都存在TBO变化;其机理研究表明,热带海洋(主要是印度洋和太平洋)和平流层QBO在TBO的形成中起着重要的作用。此外,欧亚雪盖和太阳活动的11年周期可能也会影响TBO。     

Connections between the distribution of prevailing winds in the winter Northern Hemisphere, solar/geomagnetic activity and the QBO phase

The effect of solar/geomagnetic activity and QBO phase on the distribution of winds prevailing in the winter periods (January–March) in the Northern Hemisphere at the altitude of 850 mb was studied. Analysis has shown that the zonal flow over the North Atlantic under high geomagnetic activity intensifies and under low solar/geomagnetic activity weakens. Flow deviations, associated with geomagnetic activity, are more marked under the QBO-east phase, and flow deviations, associated with solar activity, are more marked under the QBO-west phase. The results reported by Venne and Dartt (1990) concerning the wind distribution in the winter (February–March) Northern Hemisphere under high and low solar activity and a QBO-west phase, have been confirmed, and supplemented with wind distributions under high and low geomagnetic activity.     

Stratospheric ozone depletion at northern midlatitudes after major volcanic eruptions

During winter 1982/83 and in early 1985, abnormal ozone deficiencies in the stratosphere were recorded at northern midlatitude stations. Ozone variations measured by ozonesondes at Hohenpeissenberg are analysed with respect to dynamic transport variations related to the quasibiennial oscillation (QBO). After the elimination of seasonal fluctuations, long-term trends and average QBO related variations, ozone time series are compared to particle surface area densities derived from lidar measurements of the stratospheric aerosol layer at Garmisch-Partenkirchen. The two stations are only 37 km apart. The analysis reveals that the 1985 ozone minimum is a transport effect, as well as most of the 1982/83 minimum. But at 17 to 20 km in 1982/83, 30 to 40% of the ozone deficiency is most probably related to the aerosol perturbation of the lower stratosphere following the April 1982 eruption of the Mexican volcano El Chichón.     

准两年振荡及其对东亚大气环流和气候的影响

通过多年资料分析,本文研究了平流层准两年振荡(QBO)的演变特征及其对东亚及西太平洋地区大气环流和气候变化的影响.结果表明,平流层QBO的演变特征是:东风向西风转换最早出现在印度洋赤道地区;西风向东风转换最早出现在美洲和西太平洋赤道地区.中国东部降水量、气温以及西太平洋副高和东亚急流都有准两年周期变化,并同平流层QBO有密切关系;平流层QBO对西太平洋台风活动也有一定影响,QBO的西风位相期西太平洋台风偏少.另外,ENSO对于平流层QBO有明显影响,一般在ENSO发生之后,QBO的西风位相期持续时间缩短.     

IAP-AGCM对QBO模拟的动量收支分析

平流程准两年振荡(QBO)是赤道平流层(～100-1 hPa)变率的主要模态,可对中高纬地区的环流产生重要影响,但目前利用通用大气环流模式(GCM)对其进行准确模拟仍然是一个挑战.本文利用IAP大气环流模式(IAP-AGCM)的中高层大气模式版本(IAP-AGCML69)对QBO进行模拟,并对其动量收支情况进行分析.研究发现,QBO主要是由对流活动引起的重力波强迫(参数化)引起的,但该动量强迫被平流层赤道上升流所引起的平流过程显著削弱.模式可分辨尺度的波动强迫对赤道上空的QBO的总纬向风倾向有正贡献,在上平流层,其量值大小与参数化的重力波强迫相当.以上结果提供了QBO形成机制以及模式模拟差异可能原因的认识.     

Uncertainties of the relationship between the equatorial quasi-biennial oscillation, the Arctic stratosphere and solar forcing

Two different equatorial quasi-biennial oscillation (QBO) indices, two reanalyses and radiosonde observations are used to analyze the Arctic stratospheric temperature and height. This analysis was used to assess the uncertainties in the connection of solar forcing, QBO and the Arctic variability. The results show that (1) the frequency of the westerly/easterly phases of the QBO over the stratospheric equator has a significant multiple peak seasonal variation. The primary seasonal peaks occur in February, March and April for the westerly phase of the QBO and the easterly phase peaks in June, July and August. (2) The correlation of stratospheric Arctic temperature and height with the solar radio flux shows statistical significance in February or July/August even if there is no stratified phase of QBO (easterly and westerly phases) involved. However, when the correlation was computed according to the stratified phase of QBO, the solar signals in both temperature and height fields are remarkably amplified in February and November under the westerly phase, but the signal in the height field is most significant only in August under the easterly phase. (3) The impact of the QBO and solar forcing on the stratospheric temperature and heights in the Arctic varies depending on the season. The impacts are also sensitive to the specific height of the QBO-defined level that is used, the specific period of the analysis and the dataset used.