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1.
北大西洋臭氧极小值和北太平洋极大值及其相互关系 总被引：2，自引：0，他引：2
利用1979～2002年TOMS卫星观测资料,采用臭氧总量纬向偏差和区域强迫的分析方法,研究北大西洋东北部大气臭氧低值与北太平洋西北部臭氧高值的季节变化过程和相互关系.研究表明,(1)北大西洋东北部存在一个大气臭氧极小值,年平均臭氧总量比纬向平均值低20 DU以上,冬季低50 DU以上; 北太平洋西北部存在一个大气臭氧极大值,年平均臭氧总量比纬向平均值高35 DU以上,冬季高70 DU以上.(2)上述两个地区大气臭氧的季节变化具有很强的区域特征,区域大气动力学输送和化学过程对上述两个地区大气臭氧季节变化的强迫分别为50.3%和42.6%.(3)上述两个地区大气臭氧纬向偏差的季节变化间存在很好的反相关,相关系数达到-0.98,说明其臭氧区域强迫之间存在良好的关系. 相似文献
2.
E.K. Bigg 《Atmospheric Research》1990,25(6)
In a first attempt to assess a proposed climatic change feedback process involving cloud condensation nuclei (CCN) and cloud albedo, CCN concentrations N as a function of supersaturation S were measured on a voyage from latitude 43 to 65°S in October–November 1988. The usual relationship N=CSk, with k=0.5 and C a constant was a fair apprraximation for S in the range 0.3–0.7% implying that CCN concentrations should largely determine cloud drop concentrations and hence albedo for clouds with S in that range. South of latitude 50°S and at smaller S,k was 1 or larger on average, which would lead to reduced dependence of albedo on CCN for the relevant clouds. N varied very widely for separations of the order of 100 km or 6 hours in time, particularly when the sea was partly ice-covered, suggesting strong local influences. During a large increase in N 60°S, unaccompanied by an increase in condensation nuclei (CN), cloud drops grew more rapidly than usual. In a subsidiary experiment particles were collected and examined by transmission electron microscopy. For particles less than 0.2 μm diameter, 80–90% appeared to consist of ammonium sulfate, the remainder being sea salt or an unknown substance which was more liquid and heat-resistant. Dialysis showed that the sulfate particles contained a few percent of insoluble material. Particles which formed cloud drops in vapours other water, were also studied. Comparison of these and water CCN and the rates of droplet suggested that the water insoluble portion of the particles was ethanol-soluble and surface-active. CN concentrations decreased by a factor of about 2 between 43 and 65°S, a change closely paralleled by ethanol CCN concentrations. 相似文献
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青藏高原对流时空变化与东亚环流的关系 总被引：4，自引：3，他引：4
根据1980～1998年逐日TBB和NCEP/NCAR再分析资料,探讨青藏高原对流(TBB)时空分布与东亚环流及天气气候的关系.研究指出,青藏高原主体地区(28°N～34°N,80°E～102°E)的对流冬弱、夏强,存在显著的6月和10月突变现象.夏季亚洲地区最强的对流出现在青藏高原上空,呈现为高原西部(28°N～34°N,82°E～94°E)和东部(27°N～34°N,104°E～110°E)型.夏季青藏高原上空对流弱,850 hPa风场上高原南、北侧的东亚地区分别呈现西风距平,夏季中国易出现南北二条雨带; 夏季高原上空对流强,850 hPa风场上的西风距平出现在东亚30°N附近,夏季易出现江淮流域雨带.夏季江淮流域洪涝年(如1980、1993、1996、1998年)与青藏高原东、西部对流同时加强有关; 夏季江淮流域干旱年(如1992、1994、1997年)与青藏高原东、西部对流同时减弱有关.20世纪90年代,江淮流域洪涝与干旱事件频繁发生可能与青藏高原东、西部对流强度变化出现同位相的年代际变化趋势有关. 相似文献
6.
Conditional averages of principal components of the Eliassen-Palm flux divergence variability are projected onto the daily
precipitation amounts chart. The conditions of calculating the average values are determined by the dates classified in three
equiprobable precipitation categories. The classification and calculation of characteristics are performed for the summer
and winter seasons. Using the rotated principal component analysis, several regions are revealed of statistically significant
interrelation between extreme precipitation and the first EP flux divergence variability modes, a simplified exploratory interpretation
of interrelations is given and several recommendations are formulated for correcting seasonal forecasts of meteorological
conditions with the use of results obtained. 相似文献
7.
The Relationship between the Wintertime Blocking over Greenland and the Sea Ice Distribution over North Atlantic 总被引：1，自引：0，他引：1
The sea-ice concentration in the Northern Hemisphere, 500 hPa height, sea-level pressure and 1000-500 hPa thickness of monthly mean data are examined for the period 1953-1989, with emphasis on the winter season.Relationships between large-scale patterns of atmospheric variability and sea-ice variability are investigated, making use of the correlation method. The analysis is conducted for the Atlantic sectors. In agreement with earlier studies based upon monthly mean data on sea-ice concentration, the strongest sea-ice pattern is composed of a dipole with opposing centers of action in the Davis Straits / Labrador Sea region and the Greenland and Barents Seas. Its temporal variability is strongly coupled to the atmospheric North Atlantic Oscillation (NAO). The relationship between the two patterns is strongest with the atmosphere leading the ocean. The polarity of the NAO is associated with Greenland blocking episodes, during which the influence of the atmosphere is strong enough to temporarily halt the c 相似文献
8.
Peter Winkler 《Journal of Atmospheric Chemistry》1988,7(1):73-91
During the past decade (1977–1986) ozone has been measured on board various research vessels between 83° N and 76° S. The latitudinal distribution shows nearly twice as high an ozone concentration in the Northern Hemisphere (30 ppb) as compared to the Southern Hemisphere (15 ppb). North of 70° N the concentration rapidly drops to low values (17 ppb). In the ITCZ we frequently observed a pronounced secondary maximum which indicates that tropospheric-stratospheric exchange may be induced by deep convection. During other occasions, ozone concentrations below 10 ppb were observed in the ITCZ. Secondary maxima are also found in each hemisphere, indicating the latitudes in which stratospheric-tropospheric exchange occurs. One such pronounced maximum is found between 60 and 65° N. A comparable counterpart does not, however, occur in the respective southern latitudes.The observations, although incomplete, allow for conclusions with respect to seasonal cycles, at least in some of the latitudes or for some part of the year. In the tropics differences between continental and maritime yearly cycles are found. In mid to high northern latitudes, a sharp maximum is found which extends to the summer months over continental European sites. In the respective southern latitudes, such a spring maximum is only indicated.Comparison with occasionally concurrent Kr 85 measurements by other groups allows for the conclusion that in some cases photochemically produced ozone in polluted air masses is seen over the Atlantic ocean. 相似文献
9.
Considered are the results of the numerical analysis of two mesoscale cyclonic vortices generated over the Black Sea near the Caucasian coast on August 3, 2007 and August 7, 2010. It is demonstrated for the axially symmetric and more long-lived vortex occurred in 2007 that the Caucasian vortices are two-dimensional structures dying out rapidly due to the turbulent friction in the near-water boundary layer, and the deviation from the strictly two-dimensional motion is associated with the presence of the secondary circulation. The difference is demonstrated in the mechanisms of the origin of vortices in 2007 and 2010. In the first case, this is the formation of cyclonic circulation over the eastern part of the Black Sea limited by the Anatolian and high Caucasian Mountains, at the intrusion of the airflow of northwestern direction. In the second case, these are the processes of the generation of cyclonic vorticity at the baroclinic airflow running around the northwestern edge of the mountain range over the land. 相似文献
10.
A review of the understanding and progress in the study of mesoscale cellular convection (MCC) in cloud-topped marine boundary layers is provided. A comparison is made between MCC and the classical study of Benard-Rayleigh convection, with noted similarities and differences. External physical forcing mechanisms in the atmosphere are identified and discussed, in view of their effect on convection development and structure. Onset, horizontal planform, circulation direction, aspect radio and scaling phenomena are explained in terms of atmospheric processes. The global climatology of MCC is also updated and briefly discussed in terms of GCM model development. 相似文献
11.
利用1976~1995年的20年月平均NCEP/NCAR再分析资料, 对我国北方地区降水再循环率进行了评估, 结果表明:黄河流域总的降雨只有19%来自当地的水汽蒸发, 其他81%降水来自外部的水汽流；黄河上游降水主要由来自青藏高原较强的水汽所提供，因此这里的降水再循环率小于15%。但黄河上游的降水蒸发后，在西风的输送下, 为黄河下游提供了大量的水汽，通过汇合南北方向来的水汽，在黄河下游形成了降水再循环率达到30%以上的椭圆形区域。评估结果显示:降水再循环率随季节变化差异较大, 8月份的降水再循环率最高, 达31%, 而在11、12、1月份3个月的降水再循环率不到5%。结果还显示蒸发率和降水率的空间分布以及它们的年际变化都对应得很好，表明我国北方地区蒸发受降水影响较强。蒸发率、降水率和降水再循环率在20年中均有增加, 表明气候变暖对我国北方地区的水汽循环的影响已经显现。 相似文献
12.
Dr. Ye. K. Semyonov 《Theoretical and Applied Climatology》1978,25(4):305-321
Summary On the basis of extensive data of observations obtained by 272 aerological stations of the tropical zone and of radiosonde observations made in 16 Soviet oceanic expeditions the peculiarities of the equatorial westerlies in the Eastern hemisphere and their relationships with the entire mechanism of tropical circulation have been investigated. New data have been obtained on the structure, meridional extension, vertical distribution and velocity of the equatorial westerlies over Africa, the Indian ocean and the western part of the Pacific ocean. The relationship of equatorial westerlies with easterlies of the upper troposphere and with westerlies of middle latitudes is shown. In this context some features of monsoon circulation over the Guinea gulf, South-Eastern Asia and Northern Australia are discussed.Regularities of the annual migration of equatorial westerlies have been followed, the yearround existence of persistent westerlies in the lower troposphere near the equator being revealed. In order to look into the genesis and mechanism of existence of equatorial westerlies, the peculiarities of the many years distribution of cloudiness in the intertropical convergence zone (ITCZ) are considered using weather-satellite pictures presented in the US-catalogues. The features of zonal circulation in tropics are compared with the field of cloudiness of the ITCZ.
With 4 Figures 相似文献
Die äquatorialen Westwinde über der östlichen Hemisphäre
Zusammenfassung Auf Grund von umfangreichen Beobachtungsdaten von 272 Stationen in der Tropenzone und von Radiosondenbeobachtungen auf 16 sowjetischen ozeanischen Expeditionen sind die Eigenheiten der äquatorialen Westwindzone in der östlichen Hemisphäre und ihre Beziehungen zum ganzen Mechanismus der tropischen Zirkulation untersucht worden. Es sind neue Angaben über die Struktur, die meridionale Erstreckung, die vertikale Verteilung und die Geschwindigkeit der äquatorialen Westwinde über Afrika, über dem Indischen Ozean und über dem westlichen Teil des Pazifischen Ozeans gewonnen worden. Es wird die Beziehung der äquatorialen Westwinde zu den östlichen Winden der oberen Troposphäre und zu den Westwinden der mittleren Breiten gezeigt.In diesem Zusammenhang werden einige charakteristische Merkmale der Monsunzirkulation über dem Golf von Guinea, über Südost-Asien und über dem nördlichen Australien besprochen. Regelmäßigkeiten der jährlichen Verlagerung der äquatorialen Westwindzone sind verfolgt worden und die ganzjährige Existenz einer beständigen Westwindzone in der unteren Troposphäre nahe dem Äquator ist nachgewiesen worden. Um einen Einblick in die Entstehung und in den Mechanismus der Existenz äquatorialer Westwinde zu bekommen, sind die Besonderheiten der mehrjährigen Bewölkungsverteilung in der intertropischen Konvergenzzone (ITCZ) auf Grund der in den US-Katalogen veröffentlichten Wettersatelliten-Bilder in Betracht gezogen worden. Die Besonderheiten der zonalen Zirkulation in den Tropen sind mit den Bewölkungsfeldern der ITCZ verglichen worden.
With 4 Figures 相似文献
13.
Microwave measurements over the North Sea 总被引：2，自引：0，他引：2
We investigate the applicability of SLAR (Side-Looking Airborne Radar) to detect waves and other phenomena at sea, for future operational use. Especially, we investigate radar measurements of wave patterns, oil pollution, shipping traffic, and ice reconnaissance and relate these to sea-truth information. The SLAR program benefits from earlier clutter measurements at sea and in a wind-wave tank (carried out by the Physics Laboratory TNO and NIWARS), which have been further elaborated and extended. These are summarized. Results obtained since 1974 lead to the conclusion that the SLAR is applicable for the aforementioned purposes, albeit in a somewhat restricted way. The large resolution cell used, containing a vast number of independent samples, improves the dynamic resolution to about l dB and so turns the SLAR into a sensor eminently suited for the detection of very slight modulations of capillary waves. For the detection of shorter gravity waves, however, especially under severe wind conditions, a finer geometrical resolution might be needed. Results emphasize the need for further fundamental studies of sensor-object interaction. 相似文献
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《大气与海洋》2013,51(2):181-197
Abstract Moisture recycling over the Mackenzie basin is investigated by estimating the precipitation recycling ratio (the ratio of precipitation derived from local evaporation to the total precipitation within the basin) for the region with the National Centers for Environmental Prediction (NCEP) reanalysis dataset and the Meteorological Service of Canada (MSC) precipitation climatology. The results suggest that recycling is very active over the region during the warm season (April – August) and extremely inactive during the cold season. The annual recycling ratio estimated for the basin is about 0.25, which is close to that estimated by others for the Mississippi and Amazon basins despite the lower annual evapotranspiration over the Mackenzie basin. The high recycling ratios and the recycling patterns estimated for the basin during the warm season are found to be consequences of the unique topographical and climatic settings characterizing the region. Analysis of conditions during the years having anomalous spring and summer precipitation suggests that the large‐scale atmospheric setting could act in concert with the basin's unique topographic and surface characteristics to increase or to decrease precipitation and its recycling over the basin, depending on whether the basin is under the influence of a persistent large‐scale low or a high pressure system. In the former case, much of the recycled precipitation would fall over the north‐western parts of the basin where the runoff ratios are relatively high, and thus enhance the summer discharge from the basin. When the basin is under the influence of a persistent high pressure system, much of the recycled precipitation would fall over the southern part of the basin where the runoff ratios are relatively low, and thus reduce the discharge from the basin. It is suggested that this latter effect might have contributed to the record low summer discharge from the basin during 1995. 相似文献
16.
Snowstorm over the Southwestern Coast of the Korean
Peninsula Associated with the Development
of Mesocyclone over the Yellow Sea 总被引：1，自引：0，他引：1
This study investigates the characteristics of a heavy snowfall event over the southwestern part of the Korean Peninsula on 4 December 2005. The snowstorm was a type of mesoscale maritime cyclone which resulted from barotropic instability, and diabatic heating from the warm ocean in continental polar air masses. Based on surface observations, radiosonde soundings, MTSAT-1R satellite data and the 10-km grid RDAPS （Regional Assimilation and Prediction System based on the PSU/NCAR MM5） data, the evolution of the mesocyclone is explained by the following dynamics; （1） In the initial stage, the primary role in the cyclogenesis process of the mesocyclone is a barotropic instability in the horizontal shear zone. （2） In the developing stage, the mesocyclone moves and deepens into a baroclinic zone corresponding to the surface heating and moistening. （3） In the mature stage, it is found that the mesocyclone is intensified by the destabilization caused by enhanced low-level heating and condensation, the moisture flux convergence, and the interaction between upper and lower-level potential vorticity anomalies. We suggest that a checklist with stepwise indicators responsible for development be prepared for the forecasting of heavy snowfall over the southwestern part of the Korean Peninsula. 相似文献
17.
利用1980—2012年NCEP/NCAR再分析资料及中国气象局的最佳台风路径资料,研究澳大利亚冷空气活动对西北太平洋热带气旋生成的影响。研究发现,北半球夏季925 h Pa经向风超过6 m/s的频数在澳大利亚东北部海域最高,达40 d/a。为此,确定澳大利亚冷空气侵入南北半球低纬的关键区为澳大利亚东北部所罗门海地区,并用该区域经向风风速定义了一个澳大利亚冷空气活动强度指数。该指数与越赤道气流及赤道西风都有很好的相关关系,还与同期的SOI(Southern Oscillation Index,南方涛动指数)显著相关。当SOI偏低(高)时,关键区经向风风速偏强(弱)。合成分析和相关分析结果表明,澳大利亚冷空气活动强、弱年西北太平洋热带气旋生成的位置的变化与季风槽的变化一致,西北太平洋热带气旋生成总数则无显著差异。澳大利亚冷空气活动强年季风槽偏强偏东,热带气旋生成位置偏东偏南;而弱年季风槽偏弱偏西,热带气旋生成位置偏西偏北。低层涡度场、水汽输送、风垂直切变以及低纬地区对流活动的分布表明,澳大利亚冷空气活动强年有利于热带气旋生成位置偏东、偏南;弱年偏西、偏北。 相似文献
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本文主要介绍70年代以来由于计算机的发展及新的探测手段，尤其是遥感技术的发展，使短时预报工作在一些国家很迅速发展的情况。文章着重介绍了美国等国家在中小尺度系统的短时预报方面的工作、今后5—10年的一些打算及目前以及90年代中将出现的问题。文章在回顾了我国开展短时预报的情况后，介绍了80年代以来我国短时预报工作的进展，着重介绍了正在建设中的珠江三角洲、长江三角洲、京津冀、长江中上游四个基地建立短时预报工作站、探测网、通信网及强对流天气的分析研究及临近预报的情况。 相似文献
20.
Impacts of the atmospheric apparent heat source over the Tibetan Plateau on summertime ozone vertical distributions over Lhasa 
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下载免费PDF全文 Wenjun Liang Zhen Yang Jiali Luo Hongying Tian Zhixuan Bai Dan Li Qian Li Jinqiang Zhang Haoyue Wang Bian Ba Yang Yang 《大气和海洋科学快报》2021,14(3):66-71
青藏高原(TP)是一个对气候变化敏感的地区,其上空的臭氧分布影响着青藏高原及其周边地区的大气环境,北半球夏季青藏高原上空臭氧柱总量相对较低的现象,及其时空变化受到广泛关注.本研究利用北半球夏季5年的拉萨上空臭氧的气球测量数据,研究高原上空大气视热源(Q1)对臭氧垂直分布的影响并探讨了该过程的机制.结果表明,当TP上空对流层整体的Q1相对较高时,拉萨上空对流层臭氧浓度下降.大气更强的上升运动伴随着TP主体区域上空的Q1的增大.因此,当夏季Q1较高时,由于近地表低浓度臭氧空气向上输送,拉萨上空的对流层臭氧浓度下降. 相似文献