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WENSHOU TIAN MARTYN CHIPPERFIELD QIAN HUANG 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):622-635
The relatively low total column ozone (TCO) above the Tibetan Plateau (TP) observed in summer is only partly due to the thinness of the atmospheric column. In this paper the effect of the TP on the TCO is further investigated using satellite data [Total Ozone Mapping Spectrometer (TOMS) ozone column and Stratospheric Aerosol and Gas Experiment II (SAGE II) ozone profiles], ECMWF ERA-40 reanalysis data and a 3-D chemistry-climate model (CCM). It is found that the low TCO over the TP is also closely related to large-scale uplift and descent of isentropic surfaces implied by seasonal and longitudinal variations in the tropopause height. The variations in tropopause height, with a maximum in summer, can be driven by various processes including convective activity, air expansion as well as the monsoon system. While previous studies have showed an important role of troposphere-to-stratosphere transport in contributing to the observed low ozone column over the TP, the mechanism revealed in this study is an alternative amendment to the causes of the TCO low over the TP. It is also found that the monsoon anticyclone circulation induces an isentropic transport of trace gases from high latitudes towards the TP in the lower stratosphere and hence modifies tracer distributions. For the vertical distribution of ozone, the modulation by the TP is most significant below ∼20 km, that is, in the upper troposphere and lower stratosphere (UTLS). The smaller differences in NO x between Eastern TP and TP compared to large dynamically caused differences in ozone and methane imply the TCO low over the TP is mainly due to transport processes rather than chemistry. 相似文献
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在初步明确东亚沙尘气溶胶对流层-平流层输送监测事实的基础上,利用观测资料、NCEP再分析资料以及基于中尺度天气模式MM5的数值模拟方法,对一次蒙古气旋沙尘暴过程中沙尘对流层-平流层输送问题进行了初步分析.结果表明:斜压不稳定是本次蒙古气旋发展的主要强迫要素,伴随气旋发展成熟,高空切断低涡的形成引导高空急流下落并诱发对流层顶折叠和高空位涡下传.对流层顶折叠区呈漏斗状,底部达500 hPa左右.高空急流产生近似垂直的下落,并在高空切断低涡的南侧和东侧达到最强.在对流层顶折叠区周边的300-500 hPa,上升气流与低涡区偏西、偏南、偏东气流叠加,或水平横穿折叠的对流层顶,或斜升并准垂直地穿过下落的对流层顶到达平流层,且随时间的推移,空气质点能够进一步抵达平流层中部(100 hPa).轨迹分析表明,沙尘天气区对流层低层的空气质点在气旋涡旋上升气流的驱动下呈气旋式盘旋上升,并在对流层高层形成分支,一支穿过对流层顶到达平流层,并在平流层向下游进行反气旋式螺旋运动,另一支则留在对流层高层并向下游进行准水平的气旋式螺旋运动.在高空位涡下传过程中,主要产生平流层到对流层的净输送;高空位涡停止下传之后则出现对流层到平流层的净输送,且强度随时间呈指数型增长.这一特征有利于形成更强的沙尘对流层平流层输送. 相似文献
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Observation of a summer tropopause fold by ozonesonde at Changchun,China: Comparison with reanalysis and model simulation 总被引：1，自引：0，他引：1
Tropopause folds are one of the key mechanisms of stratosphere-troposphere exchange (STE) in extratropical regions, transporting ozone-rich stratospheric air into the middle and lower troposphere. Although there have been many studies of tropopause folds that have occurred over Europe and North America, a very limited amount of work has been carried out over northeastern Asia. Ozonesondes produced by the Institute of Atmospheric Physics were launched in Changchun (43.9°N, 125.2°E), Northeast China, in June 2013, and observed an ozone-enriched layer with thickness of 3 km and an ozone peak of 180 ppbv at 6 km in the troposphere. The circulation field from the European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim) dataset shows that this ozone peak was caused by a tropopause fold associated with a jet stream at the eastern flank of the East Asian trough. By analyzing the ozone data from the ozone monitoring instrument and Weather Research and Forecasting model with Chemistry (WRF-Chem) simulations, it was found that a high ozone concentration tongue originating from the lower stratosphere at high latitude (near central Siberia) intruded into the middle troposphere over Changchun between 5 and 8 km on 12 June 2013. The high-resolution WRF-Chem simulation was capable of describing events such as the tropopause fold that occurred on the cyclonic shear side of the jet stream. In addition, the TRAJ3D trajectory model was used to trace the origin of measured secondary ozone peaks in the middle troposphere back, for example, to stratospheric intrusion through the tropopause fold. 相似文献
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春季青藏高原西北侧一次平流层臭氧向对流层传输的模拟研究 总被引：1，自引：0，他引：1
利用NCEP/NCAR FNL客观分析资料和欧洲中期天气预报中心(ECMWF)的Interim再分析资料以及臭氧监测仪(OMI)的臭氧廓线资料,结合区域大气化学模式WRF-Chem对中国春季一次高空冷槽过境引起的对流层顶折卷过程(2012年3月19—21日)进行了分析,并从平流、湍流混合、对流输送等几个方面诊断分析了平流层臭氧向对流层的传输特征和细节。结果表明,发生于青藏高原西北侧的对流层顶折卷事件,其所在位置处于热带对流层顶向中纬度对流层顶的过渡区,由于陡峭的对流层顶南北梯度,在该区域发生的平流层-对流层物质交换(STE)比对流层顶东西方向折卷引起的物质交换要强烈和持久,跨越等熵面的物质交换和湍流混合对平流层-对流层物质交换有很大的贡献。大地形对平流层-对流层物质交换过程有显著的影响,且具有明显的日变化特征。早晚时段,大地形导致的爬坡上升气流显著,抑制了平流层空气与对流层空气的混合交换。午后,大地形热力作用增强,受背风坡局地环流的影响,靠近山顶处湍流混合作用对上对流层臭氧浓度升高的贡献显著增强,且地形越高,这种效应越显著。地形的湍流混合作用在2.5 km高度以上凸显,此高度之上地形平均高度每升高100 m,湍流混合的贡献增加约1%。 相似文献
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利用欧洲中心ERA5再分析资料和广州白云机场自动观测系统降水资料,分析2019年4月白云机场持续暴雨前对流层顶和平流层的信号特征。分析发现,2019年4月中下旬,广州白云机场出现了3次持续时间长、降水量大的持续性暴雨过程,降水较往年同期显著偏多。研究结果表明,3次持续暴雨发生前,对流层顶高度出现了下降,平流层高位涡冷空气入侵,机场上空位涡升高;在环流场中,中低纬地区对流层顶和平流层东风偏强,向北和向下传播,广州白云机场终端区在暴雨发生前西风持续下传;广州白云机场上空暴雨发生前对流层顶至平流层位势高度正异常。暴雨发生前,平流层冷空气高位涡移入、对流层顶下降、西风的下传均有利于持续性暴雨的生成。 相似文献
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位温、等熵位涡与锋和对流层顶的分析方法 总被引：10，自引：2，他引：8
等熵位涡分析是位涡理论的分析基础。此文的目的是介绍等熵位涡分析所必需掌握的基本概念和方法。文中从位温和位涡、对流层和平流层、锋和对流层顶的基本性质出发,讨论了锋和对流层顶在剖面图、等压面图及等位温面（即等熵面）图上的特征。文中给出了各种分析实例图形,并通过分析和对比指出：平流层的高位涡是对流层顶以上位温随高度急剧增加位温垂直梯度特别大的结果;位温垂直梯度是决定位涡分布的主要因子;等熵位涡图主要反映极地气团的活动,同时也是与极地气团密切关联的锋、急流、对流层顶的综合反映。最后提出了等熵位涡分析中需要避免的一些错误认识,特别是不能将等位温面上的流线当成轨迹的错误,并由此得出平流层空气侵入对流层下部的错误推论。 相似文献
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The impact of cut-off lows on ozone in the upper troposphere and lower stratosphere over Changchun from ozonesonde observations 总被引：1，自引：0，他引：1
In situ measurements of the vertical structure of ozone were made in Changchun(43.53?N, 125.13?E), China, by the Institute of Atmosphere Physics, in the summers of 2010–13. Analysis of the 89 validated ozone profiles shows the variation of ozone concentration in the upper troposphere and lower stratosphere(UTLS) caused by cut-off lows(COLs) over Changchun. During the COL events, an increase of the ozone concentration and a lower height of the tropopause are observed.Backward simulations with a trajectory model show that the ozone-rich airmass brought by the COL is from Siberia. A case study proves that stratosphere–troposphere exchange(STE) occurs in the COL. The ozone-rich air mass transported from the stratosphere to the troposphere first becomes unstable, then loses its high ozone concentration. This process usually happens during the decay stage of COLs. In order to understand the influence of COLs on the ozone in the UTLS, statistical analysis of the ozone profiles within COLs, and other profiles, are employed. The results indicate that the ozone concentrations of the in-COL profiles are significantly higher than those of the other profiles between ±4 km around the tropopause. The COLs induce an increase in UTLS column ozone by 32% on average. Meanwhile, the COLs depress the lapse-rate tropopause(LRT)/dynamical tropopause height by 1.4/1.7 km and cause the atmosphere above the tropopause to be less stable. The influence of COLs is durable because the increased ozone concentration lasts at least one day after the COL has passed over Changchun. Furthermore, the relative coefficient between LRT height and lower stratosphere(LS) column ozone is-0.62,which implies a positive correlation between COL strength and LS ozone concentration. 相似文献
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夏季青藏高原地区水汽向平流层的等熵绝热和非绝热传输的气候学特征及其与落基山地区的对比 总被引：2，自引：2，他引：0
夏季亚洲季风区是对流层向平流层物质输送的主要通道,其对平流层水汽的变化有重要贡献。以往的研究表明亚洲季风区向平流层的水汽传输主要在青藏高原及周边地区。本文利用多年平均的逐日ERAi、MERRA再分析数据和微波临边观测仪（Microwave Limb Sounder,MLS）数据,首先对比分析夏季青藏高原周边上空水汽的分布特征,再利用再分析资料分析了对流层—平流层水汽传输的特征。结果表明:青藏高原周边特定的等熵面和对流层顶结构分布有利于水汽向平流层的绝热输送;在南亚高压的东北侧,从青藏高原到中太平洋地区,340~360 K层次存在最为显著的水汽向平流层的纬向等熵绝热输送通道,7~8月平均输送强度可达约7×103 kg s-1。此外,在伊朗高原及南亚高压的西部,350~360 K层次也存在一支水汽向平流层的经向等熵绝热输送通道,但强度相对较弱（约2.5×103 kg s-1）。在青藏高原南侧370~380 K层次存在强的水汽向平流层的非绝热输送,主要由深对流和大尺度上升运动引起,7~8月平均输送强度约0.4×103 kg s-1。落基山以东到大西洋西部,350~360 K层次存在水汽向平流层的纬向等熵绝热输送通道,但强度也弱得多（约2.5×103 kg s-1）。 相似文献
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利用2008—2014年全国高垂直分辨率的L波段探空资料,统计分析了东亚夏季风爆发前后我国不同区域对流层顶高度变化特征。研究表明:夏季风爆发后,对流层顶高值区向北推进,最大值位于青藏高原南部及其东南部地区;对流层顶高度的向南梯度和向东梯度大值区均由爆发前的30°~40°N北移至40°~50°N;受地面加热和垂直运动的影响,中国东北部和中东部在夏季风爆发后对流层升温,平流层-对流层过渡层降温,大气温度梯度增加,对流层顶上升,其中中国东北部在夏季风爆发前,大气温度廓线为双峰结构,易出现双对流层顶,第一对流层顶较低;中国南部整层大气温度廓线在夏季风爆发后略有增加,对流层顶有所下降。 相似文献
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A. R. Ivanova 《Russian Meteorology and Hydrology》2013,38(12):808-817
Presented is a review of the papers dealing with a problem of the tropopause definition as an interface between the troposphere and stratosphere. It is demonstrated that there are more than ten approaches to the tropopause identification based on the differences in thermal, chemical, dynamic, and radiation regimes of the troposphere and stratosphere. Given are the examples of the tropopause approximation with different surfaces or layers of specific properties. 相似文献
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Air Temperature Changes over the Tibetan Plateau and Other Regions in the Same Latitudes and the Role of Ozone Depletion 总被引：3，自引：0，他引：3 
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下载免费PDF全文 Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau （TP） in comparison with those over other regions in the same latitudes from 1979 to 2002. It is shown that Over the TP, the trends of air temperature changes in the upper troposphere to lower stratosphere were out of phase with those in the lower to middle troposphere. Air temperature decreased and a decreasing trend appeared in the upper troposphere to lower stratosphere. The amplitude of the annual or seasonal mean temperature decreases over the TP was larger than that over the whole globe. In the lower to middle troposphere over the TP, temperature increased, and the increasing trend was stronger than that over the non-plateau regions in the same latitudes in the eastern part of China. Meanwhile, an analysis of the satellite observed ozone data in the same period of 1979-2002 shows that over the TP, the total ozone amount declined in all seasons, and the ozone depleted the most compared with the situations in other regions in the same latitudes. It is proposed that the difference between the ozone depletion over the TP and that over other regions in the same latitudes may lead to the difference in air temperature changes. Because of the aggravated depletion of ozone over the TP, less （more） ultraviolet radiation was absorbed in the upper troposphere to lower stratosphere （lower to middle troposphere） over the TP, which favored a stronger cooling in the upper troposphere to lower stratosphere, and an intenser heating in the lower to middle troposphere over the TP. Therefore, the comparatively more depletion of ozone over the TP is possibly a reason for the difference between the air temperature changes over the TP and those over other regions in the same latitudes. 相似文献
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基于1979—2014年ERA-Interim逐日再分析温度资料,依据温度递减率插值法计算出青藏高原及同纬度其他地区热带对流层顶气压数据,比较了高原和同纬度其他地区热带对流层顶气压季节变化和长期变化趋势,讨论了热带对流层顶气压与高空温度的关系。结果表明:1)在季节变化上,除12月和1月外,青藏高原热带对流层顶气压全年低于同纬度其他地区;青藏高原热带对流层顶气压、对流层中上层以及平流层下部平均温度均表现出比同纬度其他地区更明显的单峰型特征。2)热带对流层顶气压与高空温度变化关系密切,对流层中上层(平流层下部)平均温度升高(降低),有利于热带对流层顶气压降低;相对于同纬度其他地区,青藏高原对流层顶气压与对流层中上层平均温度的关系更密切。3)1979—2014年青藏高原和同纬度其他地区各季节的热带对流层顶气压均呈现出不同程度的下降趋势,冬春季下降趋势更加显著;青藏高原各季节对流层中上层增温和平流层下部降温的幅度均超过同纬度其他地区,导致其热带对流层顶气压的下降趋势比同纬度其他地区更加明显。 相似文献
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夏季亚洲季风区对流层向平流层输送的源区、路径及其时间尺度的模拟研究 总被引：9，自引：4，他引：5
基于NCEP/NCAR分析资料和拉格朗日轨迹输送模式FLEXPART, 通过气块轨迹计算, 对2005年夏季亚洲季风区对流层向平流层输送 (Troposphere to Stratosphere Transport, 简称TST) 的近地层源区、 输送路径及其时间尺度问题进行了一些初步探讨。结果表明: (1) 夏季亚洲季风区TST两个主要的边界层源区, 一个是热带西太平洋地区; 另一个是青藏高原南部、 孟加拉湾以及印度半岛中北部等地区, 上述两个区域与夏季强对流的分布相一致。在对流层顶高度附近 (约16 km高度), 两个近地层源区的垂直输送贡献相当。但进一步分析发现, 穿越对流层顶高度的质量输送只有约10％能够进入20～22 km高度的平流层中, 且主要源于以青藏高原南侧为代表的南亚季风区 (约贡献75%), 这进一步强调了青藏高原及其周边区域在全球TST过程中的重要地位。 (2) 轨迹分析显示, 夏季亚洲季风区对流层进入平流层的 “入口区” 主要在 (25°N～35°N, 90°E～110°E) 区域的青藏高原及其周边区域。TST路径受对流层上层南亚高压闭合环流、 北半球副热带西风急流和赤道东风急流的共同控制。 (3) 亚洲季风区TST两个主要的过程, 一个是和夏季湿对流抬升直接联系的快速输送过程, 它可以使近地层大气在1～2天内输送到平流层中, 贡献了整个TST的10%～30%; 另一个是大气辐射加热所致的大尺度垂直输送, 该输送是一个相对的慢过程, 时间尺度一般为5～30天。此结果意味着, 源于地表的短生命周期的大气污染物可通过光化学反应过程对该区域平流层臭氧及其他大气痕量成分平衡产生重要影响。 相似文献
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n this paper,using NCEP dataset and the Wei's method,we calculate the exchange of massacross the thermal tropopause during 1998 over the Tibetan Plateau and its surroundings.Theresults indicate that:(1)There is strong air transport from troposphere to stratosphere in summerover the Tibetan Plateau and its surroundings.The air transport reaches the summit in midsummerwith three large value centers among which the Bay of Bengal is the largest and the other two largecenters lie in the east and northwest of the Tibetan Plateau,respectively.In May and October thecross-tropopause mass exchange reaches balance.In other months the mass transport is fromstratosphere to troposphere.(2)As far as the cross-tropopause mass exchange from June toSeptember in 1998 is concerned,the net mass transport is 13.7×10~(18) kg from troposphere tostratosphere,So the area from Tibetan Plateau to the Bay of Bengal is a channel through which airmass gets into stratosphere from troposphere. 相似文献
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深对流能够向上对流层—下平流层（UTLS）输送大量水汽和污染物,对对流层顶的辐射平衡、平流层的臭氧恢复以及全球气候变化都有着重要的影响。近年来,一系列重要的观测事实发现,青藏高原和亚洲季风区是对流层向平流层物质输送（TST）的重要窗口。本文介绍了近年来取得的一些主要进展和成果,包括:（1）通过卫星观测在青藏高原—亚洲季风区上空发现水汽、气溶胶的极大值区和臭氧的极小值区;（2）深对流活动的主要观测途径和通过卫星观测识别深对流的方法;（3）青藏高原深对流向平流层物质输送的物理过程;（4）青藏高原深对流与亚洲季风区、热带海洋地区深对流的结构差异以及不同环境场对深对流物质输送过程的影响。 相似文献
17.
采用UARS卫星1993—2004年卤素掩星试验的观测资料(HALOE),分析了青藏高原(下称高原)上空大气中H2O和CH4的分布和季节变化,也与同纬度其它地区作对比,找出它们的差异,并分析了H2O和CH4的多年变化趋势。结果表明:高原上空H2O混合比在对流层上层随高度迅速减少,在对流层顶和平流层底达到极小值,平流层里水汽混合比随高度增加。高原上空CH4混合比从140 hPa直至1 hPa随高度递减。在对流层上部和平流层下部H2O和CH4混合比季节差异最明显。高原上空H2O和CH4混合比与同纬度带其它地区相比有不少差异,这种差异在对流层上部和平流层下部更明显。分析还表明:高原上空对流层上部和平流层下部H2O和CH4的分布明显受到高原热力作用引起的垂直运动的影响,高原区域是平流层和对流层交换的活跃区。平流层中上层H2O和CH4的关系很密切,其原因主要是在平流层中上层CH4很容易被氧化成H2O。趋势分析表明,在对流层顶附近,水汽在1993—2004年呈下降趋势,而CH4在1998年以前和2001年以后也呈下降趋势;平流层中层1993—2000年H2O混合比呈增加趋势,CH4呈下降趋势,2000—2004年H2O混合比呈下降趋势,而CH4呈增加趋势。 相似文献
18.
北京地区对流层顶变化及其对上对流层/下平流层区域臭氧变化的影响 总被引：7，自引：4，他引：7
根据2001～2003年期间获得的大气臭氧探空资料,揭示了北京地区上空对流层顶高度的某些变化特征及其对上对流层(UT)和下平流层(LS)区域内大气臭氧含量变化的影响.结果显示:北京地区上空对流层顶高度的平均值约11.1 km,其变化范围为7.7～14.4 km,臭氧层顶始终处在对流层顶下方约0.9 km高度处.对流层顶高度变化与臭氧总量变化之间的关系相对较弱.通常情况下,LS中的臭氧积分量明显高于UT中的相应值,并且二者呈相反的季节变化特征.北京地区上空仲夏和初秋季节第一对流层顶出现的频数明显减少,在第一对流层顶消失的情况下,LS中的臭氧积分量明显减少,而UT中的臭氧积分量明显增加,臭氧量减少最多发生在200～100 hPa层次中,而臭氧量增幅最大的层次是400～250 hPa. 相似文献
19.
利用国产GPSO3臭氧探空系统观测的大气臭氧探空资料和NCEP再分析资料,结合对天气形势、大气环流背景、高空位涡变化及对流层顶高度扰动的分析,深入研究了2008年冬季北京地区10~14 km高度范围内持续出现的臭氧次峰值及大气臭氧含量异常现象。结果表明:在2008年我国南方雪灾这一特殊时期,引起臭氧垂直分布持续出现次峰值现象及臭氧含量异常的主要原因是平流层空气强烈下沉运动及其与对流层的交换作用,而引起这种下沉运动及平流层-对流层交换则是由于该阶段特殊的天气背景,乌拉尔阻塞高压长时间维持,贝加尔湖到巴尔喀什湖一带横槽稳定存在,里海以东切断低压长期维持,造成冷空气长时间、稳定地南下影响北京上空臭氧的垂直分布。加之副热带急流的出现,北京正处于其入口区左侧,其上空有强烈的辐合下沉运动,有利于平流层空气向下输送。此次臭氧次峰值及臭氧含量异常的现象很好地说明,在冷空气天气过程的影响下,北京地区上空的平流层空气运动及其与对流层的交换十分活跃。 相似文献
20.
A. R. Ivanova 《Russian Meteorology and Hydrology》2016,41(3):170-185
A review of the papers dealing with various aspects of stratosphere-troposphere exchange (STE) is presented. The development of STE concepts is described and quantitative estimates of STE obtained by different authors are given. Typical time scales and geographic features of STE are described. Special attention is given to the specific features of STE at extratropical latitudes where active vertical air transport is observed in both directions. The air ascent through the tropopause occurs there in the zones of warm conveyor belts, and the air descent takes place in the zones of stratospheric intrusions. Exchange processes in the key region including the upper troposphere and the lowermost stratosphere are described. The mechanisms of large-scale stratospheric intrusions in the systems of tropopause folds or cut-off lows are presented as well as the mechanisms of the mixing of the stratospheric air with the tropospheric one. Specific features of deep stratospheric intrusions are discussed which are based on the analysis of such indicators of stratospheric air as high concentrations of ozone and stratospheric radionuclide 7Be. Some aspects of stratosphere-troposphere energy exchange are considered. 相似文献