2001年春季临安地区对流层臭氧异常增加的一次过程分析   总被引：6，自引：0，他引：6  

崔宏  赵春生  郑向东  郑永光  秦瑜  陈尊裕  陈鲁言 《大气科学》2005,29(2):259-266

2001年春季在临安(30.30°N,119.75°E)进行的臭氧垂直探测发现,从3月25到31日有一次明显的臭氧异常增加过程,其中尤以29日和30日对流层上层的臭氧异常增加最具代表性.结合分析地面及高空气象要素演变和高空位势涡度的变化表明,这是一次显著的平流层空气由上向下穿过对流层顶深入对流层的下传过程,此平流层对流层交换过程与冷空气南下的天气过程和副热带急流、极锋急流移动造成的辐合下沉运动有着密切的联系.  相似文献   

Dynamical and Chemical Features of a Cutoff Low over Northeast China in July 2007: Results from Satellite Measurements and Reanalysis     

LIU Chuanxi  LIU Yi  Xiong LIU  Kelly CHANCE 《大气科学进展》2013,30(2):525-540

The European Centre for Medium-Range Weather Forecasts Re-Analysis Interim (ERA-Interim) meteorology and measurements from the Microwave Limb Sounder, High Resolution Dynamics Limb Sounder, and Ozone Monitoring Instrument onboard the Earth Observing System Aura satellite were applied to analyze the dynamical and chemical features of a cutoff low (COL) event over northeast China in early July 2007. The results showed the polar stratospheric origin of an upper-level warm-core cyclone at 100--300 hPa, associated with a funnel-shaped tropopause intruding into the mid-troposphere just above the COL center. The impacts of the stratospheric intrusion on both column ozone and ozone profiles were investigated using satellite measurements. When the intensity of the COL peaked on 10 July 2007, the total column ozone (TCO) increase reached a maximum (40--70 DU). This could be dynamically attributed to both the descent of the tropopause (～75%) and the downward transport of stratospheric ozone across the tropopause (～25%). Analysis of the tropospheric ozone profiles provided evidence for irreversible transport/mixing of ozone-rich stratospheric air across the tropopause near the upper-level front region ahead of the COL center. This ozone intrusion underwent downstream transport by the upper tropospheric winds, leading to further increase in TCO by 12--16 DU over broad regions extending from east China toward the northern Japan Sea via South Korea. Meteorological analysis also showed the precedence of the stratospheric intrusion ahead of the development of cyclones in the middle and lower troposphere.  相似文献   

Upper-bound general circulation of coupled ocean–atmosphere: Part 1. Atmosphere     

《Dynamics of Atmospheres and Oceans》2013

We consider the general atmospheric circulation within the deductive framework of our climate theory. The preceding three parts of this theory have reduced the troposphere to the tropical and polar air masses and determined their temperature and the surface latitude of their dividing boundary, which provide the prior thermal constraint for the present dynamical derivation. Drawing upon its similar material conservation as the thermal property, the (columnar) potential vorticity (PV) is assumed homogenized as well in air masses, which moreover has a zero tropical value owing to the hemispheric symmetry. Inverting this PV field produces an upper-bound zonal wind that resembles the prevailing wind, suggesting that the latter may be explained as the maximum macroscopic motion extractable by random eddies – within the confine of the thermal differentiation.With the polar front determined in conjunction with the zonal wind, the approximate leveling of the isobars at the surface and high aloft specifies the tropopause, which is colder and higher in the tropics than in the polar region. The zonal wind drives the meridional circulation via the Ekman dynamics, and the preeminence of the Hadley cell stems from the singular Ekman convergence at the equator that allows it to supply the upward mass flux in the ITCZ demanded by the global energy balance.  相似文献   

Oxygen and Hydrogen Isotopic Signatures of Large Atmospheric Ice Conglomerations     

J. Martinez-FrÍAs  A. Delgado  M. MillÁN  E. Reyes  F. Rull  D. Travis  R. Garcia  F. LÓPez-Vera  J. A. RodrÍGuez-Losada  J. A. Martin-Rubi  J. Raya  E. Santoyo 《Journal of Atmospheric Chemistry》2005,52(2):185-202

Specific studies about the stable isotope composition (¹⁸O/¹⁶O and D/H) of atmospheric icy conglomerations are still scarce. The present work offers, for the first time, a very detailed analysis of oxygen and hydrogen isotopic signatures of unusually large ice conglomerations, or “megacryometeors”, that fell to the ground in Spain during January 2000. The hydrochemical analysis is based on the bulk isotopic composition and systematic selective sampling (deuterium isotopic mapping) of eleven selected specimens. δ¹⁸O and δD (V-SMOW) of all samples fall into the Meteoric Water Line matching well with typical tropospheric values. The distribution of the samples on Craig's line suggests either a variation in condensation temperature and/or different residual fractions of water vapour (Rayleigh processes). Three of the largest megacryometeors exhibited unequivocally distinctive negative values (δ¹⁸O = −17.2%₀ and δD = −127 %₀ V-SMOW), (δ¹⁸O = −15.6%₀ and δD = −112%₀ V-SMOW) and (δ¹⁸O = −14.4%₀ and δD = −100%₀ V-SMOW), suggesting an atmospheric origin typical of the upper troposphere. Theoretical calculations indicate that the vertical trajectory of growth was lower than 3.2 km. During the period in which the fall of megacryometeors occurred, anomalous atmospheric conditions were observed to exist: a substantial lowering of the tropopause with a deep layer of saturated air below, ozone depression and strong wind shear. Moreover, these large ice conglomerations occurred during non-thunderstorm conditions, suggesting an alternative process of ice growth was responsible for their formation.  相似文献   

Variability of Near-Ground Ozone Concentrations During Cold Front Passages – a Possible Effect of Tropopause Folding Events     

H. Kunz  P. Speth 《Journal of Atmospheric Chemistry》1997,28(1-3):77-95

The analysis of surface ozone variability requires besides chemicalstudies the consideration of meteorological conditions and dynamicprocesses. Our research focuses on the mechanisms in connection with coldfront passages. A statistical study and case studies of cold front passageswere carried out at six German ground-based sites during the year 1990.After the passage of cold fronts three typical developments of thenear-ground ozone concentrations could be identified. Usually the ozoneconcentrations decrease due to advection of clean air masses or due toenhanced cloudiness preventing the photochemical production of ozone,chemical destruction by nitrogenoxides, and heterogeneous chemistry. In somecases the concentrations increased by reason of downward mixing of ozoneenriched air intruded from the stratosphere into the troposphere bytropopause foldings. For a few cases no modification set in. The decreasewas mostly twice as strong as the increase. The latter was between 4 and 8ppb on the average. Special emphasis is given to the transport ofstratospheric ozone down to the ground. There is no direct evidence forstratospheric ozone at ground level, because it cant be distinguished fromthe tropospheric one, but from case studies circumstantial evidence is foundin favour of it. As an example of increasing ozone behind the passage ofcold fronts one case study typical of all other case studies is presented.It shows the characteristic properties of the corresponding fronts, whichare fast movement, a vertical split structure and strong convection.  相似文献   

皖北地区对流层顶气象特征分析   总被引：2，自引：0，他引：2  

路传彬  陈娟  华行祥 《沙漠与绿洲气象(新疆气象)》2014,(1):28-31

利用阜阳高空气象站2007—2011年08时的对流层顶气象资料,运用统计学方法,对皖北地区两类对流层顸的气象特征进行分析。结果表明：极地类对流层顶与热带类对流层顶大部分时间并存于皖北地区上空,7、8、9月极地类对流层顶消失;热带类对流层顶的高度先扬后抑,5月最高,11月最低,温度先降后升,12月最高,9月最低;极地类对流层顶的高度上半年不断抬高,下半年依次走低,温度年头高、年中低;两类对流层顶季节性特征的变化大体上呈正相关关系,极地类对流层顸季节性变化较大。  相似文献   

夏季风爆发前后中国区域对流层顶高度变化特征          下载免费PDF全文

姜晓玲  王东海  尹金方  林文实 《应用气象学报》2016,27(4):445-453

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   

Satellite-based Observational Study of the Tibetan Plateau Vortex:Features of Deep Convective Cloud Tops     

Yi-Xuan SHOU  Feng LU  Hui LIU  Peng CUI  Shaowen SHOU  Jian LIU 《大气科学进展》2019,36(2):189-205

In this study, an east-moving Tibetan Plateau vortex (TPV) is analyzed by using the ERA-5 reanalysis and multi-source satellite data, including FengYun-2E, Aqua/MODIS and CALIPSO. The objective is to demonstrate: (i) the usefulness of multi-spectral satellite observations in understanding the evolution of a TPV and the associated rainfall, and (ii) the potential significance of cloud-top quantitative information in improving Southwest China weather forecasts. Results in this study show that the heavy rainfall is caused by the coupling of an east-moving TPV and some low-level weather systems [a Plateau shear line and a Southwest Vortex (SWV)], wherein the TPV is a key component. During the TPV's life cycle, the rainfall and vortex intensity maintain a significant positive correlation with the convective cloud-top fraction and height within a 2.5° radius away from its center. Moreover, its growth is found to be quite sensitive to the cloud phases and particle sizes. In the mature stage when the TPV is coupled with an SWV, an increase of small ice crystal particles and appearance of ring- and U/V-shaped cold cloud-top structures can be seen as the signature of a stronger convection and rainfall enhancement within the TPV. A tropopause folding caused by ageostrophic flows at the upper level may be a key factor in the formation of ring-shaped and U/V-shaped cloud-top structures. Based on these results, we believe that the supplementary quantitative information of an east-moving TPV cloud top collected by multi-spectral satellite observations could help to improve Southwest China short-range/nowcasting weather forecasts.  相似文献   

The APE-THESEO Tropical Campaign: An Overview     

L. Stefanutti  A. R. MacKenzie  V. Santacesaria  A. Adriani  Stefano Balestri  S. Borrmann  V. Khattatov  P. Mazzinghi  V. Mitev  V. Rudakov  C. Schiller  G. Toci  C. M. Volk  V. Yushkov  H. Flentje  C. Kiemle  G. Redaelli  K. S. Carslaw  K. Noone  Th. Peter 《Journal of Atmospheric Chemistry》2004,48(1):1-33

The APE-THESEO campaign was held from 15 February to 15 March 1999 from the Seychelles in the western Indian Ocean. APE-THESEO stands for Airborne Platform for Earth observation — (contribution to) the Third European Stratospheric Experiment on Ozone. The campaign aimed to study processes controlling the low water content of the stratosphere, including the mechanisms of cloud formation in the tropical tropopause region, and transport processes, studied using measurements of long-lived trace gases and ozone.Two aircraft were used: the high-altitude research aircraft, M-55 Geophysica, which can fly up to 21 km, and the Falcon of the Deutsches Zentrum für Luft- und Raumfahrt, a tropospheric aircraft. Seven flights were performed, including the first simultaneous in situ and remote sensing of sub-visible cirrus clouds, the first interception of sub-visible cirrus using in-flight guidance from a path-finding aircraft, and guided descent of a high-altitude research aircraft into the anvil cloud at the top of a tropical cyclone. In this paper we describe the payload used, the objectives for each flight, and the meteorological conditions encountered. First results show that a new type of cloud, which we have dubbed ultra-thin tropical tropopause cloud (UTTC), has been observed frequently, and observed to cover areas of 10⁵ km². The frequent coincidence of the tropopause and hygropause implies that the western Indian Ocean played an important role in the dehydration of the lower tropical stratosphere during the season of the mission. UTTCs, sub-visible cirrus, and visible cirrus, have all been implicated in the observed dehydration. Tracer measurements indicate little mixing of stratospheric air into the upper tropical troposphere.  相似文献   

北京地区极地对流层顶与地面要素之间的关系   总被引：4，自引：0，他引：4       下载免费PDF全文

吴香玲 《气象》1995,21(11):42-45

利用北京地区１９７７－１９９０年的高空、地资料，讨论了极地对流层顶与地面温度的关系。发现两者之间正相关关系较好。然而，当两者谷值出现的月份发生位相关异时，当年年降水相对变率大于同期降水的平均相对变率。  相似文献