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夏季青藏高原热力场和环流场的诊断分析——Ⅱ:环流场的主要特征及其大型垂直环流场 总被引：8，自引：0，他引：8
本文使用经过青藏高原气象科学实验测站观测资料订正过的欧洲中心FGGE-Ⅲb资料,对1979年7月月平均进行分析,计算了垂直速度、散度、垂直剖面函数和速度势函数等物理量以及上升气流轨迹,给出了夏季高原主体地区环流场的主要特征和详细的高原地区不同经纬度剖面垂直环流场的特征和分布. 配合夏季高原高层强大稳定的反气旋高压带,高原主体地区为整层上升气流区,但ω场有东西两个上升中心,它们是两个对流活动上升中心,两部的中心位于狮泉河和改则之间偏北的地区,东部的位于那曲一带. 本文给出了高原地区三个主要的经向环流圈(南北两侧下沉的小环流圈、跨赤道的季风环流圈)的经度位置和高原地区与西太平洋之间发生遥相关的主要纬度位置,发现在跨赤道的季风环流圈中,在赤道以南的下沉气流主要来自高原与15°N之间,从高原上升的气流仅在对流层上部(200hPa左右)跨过赤道.从高原西部上升的气流往往从非洲至印度尼西亚一带跨过赤道,而从高原东部及其东侧我国大陆上升的气流往往下沉在太平洋和北大西洋地区. 相似文献
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地形与城市环流共同作用下的β中尺度暴雨 总被引：31，自引：12，他引：19
从中尺度天气动力学理论入手, 利用尺度分析的方法, 得到了地形与城市热岛共同作用下的β中尺度暴雨的一系列理论特征。利用北京地区稠密的地面观测网资料以及分布于距暴雨中心区不同距离的两部风廓线仪观测资料, 通过分析2006年夏季发生的3次β中尺度暴雨酝酿、 发生、 发展、 维持过程中的气温、 降水、 风场的配置关系, 对β中尺度暴雨的部分理论特征进行了验证。主要结论: (1) 由城市热岛形成的水平温度梯度有可能在靠近城区的山前迎风坡强迫产生相对独立的中尺度风的垂直切变, 由此产生的低空风的垂直切变是维系中尺度对流降水发生、 发展的重要条件。另一方面, 一旦迎风坡出现强降水, 将形成吹向迎风坡的风速与降水强度之间的正反馈现象, 这种正反馈过程对β中尺度暴雨的形成过程起到了重要作用; (2) 地形越靠近城区, 山前越容易形成强的水平温度梯度, 进而越容易出现低空风的垂直切变。形成强低空风的垂直切变的响应时间取决于水平温度梯度的强度; (3) 地形坡度越大的地方, 产生的上升运动越强, 中尺度系统的水平尺度越小, 对于地形坡度较为平坦的地方, 更有利于产生水平尺度较大的中尺度系统; (4) 一般情况下, 地形与城市热力过程造成的中尺度暴雨过程多发生于傍晚前后或凌晨前后。 相似文献
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登陆台风Matmo（2014）北侧弱回波区突发多条强对流雨带,造成严重影响。本文利用NECP/NCAR的FNL（Final）再分析资料,地面自动站加密观测资料、雷达拼图资料等对台风北侧连续出现的3条对流雨带的触发和发展过程进行研究。结果表明:初始对流是在弱的对流不稳定和条件对称不稳定条件下,由锋面强迫和地形抬升作用共同触发。接二连三发生的3条对流雨带是在台风北部高湿环境,长时间稳定的水汽辐合,明显的对流不稳定,局部弱条件对称不稳定条件下,由近地面辐合线在辐合稳定并加强后触发的,有利的环境和多层不稳定的叠加有利于雨带的发展和维持。先后触发对流雨带的3条辐合线在发生位置上相当接近。辐合线的形成一方面由海陆下垫面差异、江苏和山东南部海岸线曲率、台风风速随半径分布特点所决定;另一方面,辐合线2和3的形成还与它们北侧对流雨带的冷出流密切相关。对流带上的强降水中心往往对应着稳定的辐合中心,辐合中心主要位于风速大小梯度明显的位置上。而辐合线上的风速梯度主要受海岸线、地形附近的降水分布影响。 相似文献
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The exponential growth in global populations, economic activity and resource utilization means it is becoming increasingly difficult to satisfy global demand for a number of fundamental resources, while some key ecosystems services are under stress. The likelihood of future resource scarcities have begun to influence the positions taken within international climate change negotiations by fast-growing developing countries. When Brazil, South Africa, India, and China formed the BASIC group it took many by surprise. The coordination needed to align this heterogeneous group of countries cannot simply be understood in terms of a set of shared interests around climate policy. How the BASIC group emerged and the nature of its cooperation on climate change are examined within the broader context in which these increasingly powerful countries came to join forces. Although traditionally aligned with the G77 group of developing countries, recent strategising as a group of emerging economies reflects their realization that there are insufficient global resources available to follow the same development pathway as industrialized countries. Hence, they must seek alternative growth pathways, which requires establishing common ground while also keeping track of each others' positions on important global issues like climate change. 相似文献
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陕北地区植被治理与退化对一次区域降水过程影响的数值模拟 总被引：5，自引：0，他引：5
针对陕北地区一次区域性降雨个例 ,运用中尺度模式MM5V3 5进行了陕北地区植被治理和退化的敏感性试验。结果表明 ,植被生态治理后 ,能够使区域的平均降水量增加 ,使地表净盈余水分 7 6% ;植被退化使降水量减少 ,地表亏失水分 3 6%。植被变化对降水的影响有热力和动力两方面原因 :一方面 ,植被改善后 ,地气之间的热通量增大 ,地表对大气的增温作用增强 ,使低层大气更趋于不稳定 ;另一方面 ,植被改善增大了地表的非均一性 ,能够激发出一定强度的局地次级环流叠加于天气尺度系统上。这两种作用 ,使系统加深并发展 ,增加到达地面的降水量。植被退化则产生与上述相反的作用 ,导致局地降雨量的减小 ,使地面进一步干旱化。 相似文献
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长白山地处吉林省东南部,作为国家级重点生态功能区,其降水变化特征对该地森林生态系统和水资源结构变化有重要影响。本文基于1979～2016年吉林省47个台站逐月降水资料,探究了长白山天池站夏季降水的气候特征及其相关的环流异常,并与吉林省降水进行对比。分析结果表明天池夏季降水量以及年际变率高出吉林省其它站点一倍左右。此外,天池降水年际变化对应的环流异常与吉林省降水一致,即6月东北亚气旋式异常和东亚高空急流的增强,以及7、8月西太平洋副热带高压增强和东亚高空西风急流偏北,均可引起吉林省和天池降水偏多。另一方面,天池降水变异还表现出其独特的环流异常,与吉林省降水对应的环流异常显著不同或者甚至近乎相反,究其原因为长白山地形所致。本文的结果说明山地的气候和大气环流的关系复杂、多变。 相似文献
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The role of radiative-convective interaction in creating the microclimate of urban street canyons 总被引：2，自引：2，他引：2
Hanna Swaid 《Boundary-Layer Meteorology》1993,64(3):231-259
An approximate sky view factor (SVF) has been developed, which is capable of estimating the mean rate of net longwave radiant energy loss from urban street canyons. Reduced scale models of typical canyon geometries were used in outdoor tests to verify the predictions of radiant fluxes obtained using the proposed SVF. Air-surface temperature differences from the scale models are used together with hypothesized within-canyon airflow patterns to determine some quantitative characteristics of the wind field in canyons. Simple correlations are proposed for the relationship between mean in-canyon and pedestrian-level flow speeds on the one hand, and the ambient (above roof-level) wind speed on the other hand. As expected, the height/width ratio of a canyon controls the form and magnitude of the flow within. 相似文献
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《Atmospheric Research》2010,95(4):663-674
The Siberian Anticyclone (SA) is one of the dominant cold season synoptic systems of the northern hemisphere. The effects of the SA on the areas over which it appears to reside on synoptic maps are well established. This study examines the impacts that the SA has on local climate in areas far beyond the area of its domination. The existence of any teleconnection patterns derived from the SA sea level pressure (SLP) characteristics and their relation to precipitation over Cyprus are examined. Four indices were created describing the characteristics (behavior) of the SA (strength and geographical displacement). In an attempt to identify possible relations between precipitation, on the one hand, and the SA indices, on the other hand, a network of 32 rain gauge stations in Cyprus, both coastal and inland, was carefully selected to cover the whole island. The pressure field of the SA was found to affect the precipitation of each month differently. The results are consistent for each case and it was found that the geographical location of each station plays an important role. All four indices were found to be related to precipitation. 相似文献
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SHEN Wu ZHOU Jialing MA Jingxian CHEN Lianshou LUO Zhexian 《Acta Meteorologica Sinica》2007,21(3):290-301
In the context of advection dynamics,19 experiments(Exps.)are performed using a quasi-geostrophic barotropic vorticity equation model to explore the condition for the mergence of binary vortices and the self-organization of the larger scale vortex.Results show that the initial distance between the centers of binary vortices and the non-axisymmetric distributions of their initial vorticity are two factors affecting the mergence of binary vortices.There is a critical distance for the mergence of initial symmetric binary vortices, however,the mergence of initial non-axisymmetric binary vortices is also affected by the asymmetric structure of initial vortices.The self-organization processes in 19 experiments can be classified into two types:one is the merging of identical,axisymmetric binary vortices in which the interaction of the two vortices undergoes slowly change,rapid change,and the formation,stretching,and development of the filaments of vorticity, and the two vortices merge into a symmetric vortex,with its vorticity piled up in the inner region coming from the two initial vortices,and the vorticity of the spiral band in the outer region from the stretching of the filaments of the two initial vortices.And the other type is the merging of the two non-axisymmetric initial vortices of an elliptic vortex and an eccentric vortex in which the elliptic vortex,on the one hand, mutually rotates,and on the other hand moves towards the center of the computational domain,at the same time expands its vorticity area,and at last forms the inner core of resultant state vortex;and the eccentric vortex mutually rotates,meanwhile continuously stretches,and finally forms the spiral band of resultant state vortex.The interaction process is characteristic of the vorticity piled up in the inner core region of resultant state vortex originating from the elliptic vortex and the vorticity in spiral band mainly from the successive stretch and rupture of the eccentric vortex. 相似文献
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本文研究时间序列的变点问题。所给出的统计方法可用来推断一个时间序列是否存在变点，存在几个变点以及变点在什么位置。这种统计推断方法可用于气候阶段的划分。 相似文献
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If oceanic models are to be driven with transient atmospheric input, data from standard daily analyses or from an atmospheric GCM simulation can be used. The question arises whether these “FF-data” (FF = field forcing) are appropriate to be used as a realistic oceanic forcing in the form of wind stress and turbulent heat fluxes.A series of different FF-data sets is compared with respective “LF-data” (LF = local forcing) derived from in situ weathership observations. We believe these LF data to be the most accurate and reliable long year maritime time series. The study is restricted to 8 Atlantic weatherships and January conditions and to fields obtained with the Hamburg University GCM or derived from analyses of the German Weather Service (DWD).It turns out that DWD based FF data sets are suitable only if long year mean values are required. In general, the interannual and synoptic scale variability is too small for all FF data sets. With respect to the windstress, the empirical formulae to obtain the surface wind (from the sea level pressure field) together with the usage of a windspread dependent drag coefficient yield the best though still unsatisfying results. The approach using generalized similarity theory gives worse results with respect to the synoptic scale and interannual variability.The GCM simulated data set is systematically biased over wide regions which is partly due to a shift in the model's quasistationary Icelandic Low and an increased temperature at the model's lowest level. The transients are simulated at some positions even poorer than those analysed by the DWD, but at other positions superior though still weaker than the LF data's. 相似文献
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This conceptual review article provides a critical appraisal of Sustainable Consumption and Production research, which is currently framed by two generic positions. First, the ‘reformist’ position, which focuses on firms pursuing green eco-innovations and consumers buying eco-efficient products, represents the political and academic orthodoxy. Second, the ‘revolutionary’ position, which is a radical critique of the mainstream, advocates the abolishment of capitalism, materialism, and consumerism, and promotes values such as frugality, sufficiency, and localism. We find this dichotomous debate problematic, because it is intellectually stifling and politically conservative (in its outcomes). To move beyond this dichotomy, we propose a third position, ‘reconfiguration’, which focuses on transitions in socio-technical systems and daily life practices and accommodates new conceptual frameworks. For each of the three positions, we discuss: (1) the scale and type of change, (2) views on consumption and production in exemplary approaches, (3) underlying theoretical, epistemological and normative orientations, (4) policy implications, and (5) critical appraisal. The conclusion compares the three positions, provides arguments for the fruitfulness of the reconfiguration-position and offers four critical reflections about future Sustainable Consumption and Production research agendas. 相似文献
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M Andree H Oeschger W Broecker N Beavan M Klas A Mix G Bonani H J Hofmann M Suter W Woelfli T-H Peng 《Climate Dynamics》1986,1(1):53-62
In this paper we present accelerator radiocarbon measurements on hand picked benthic and planktonic foraminifera separated from two deep sea cores raised from the South China Sea. From the benthic-planktonic age differences we are able to place limits on the extent to which the ventilation rate of the deep Pacific Ocean has changed over the last 12000 years. While much work remains to be done before any definitive answers for the global oceans can be given, these results on cores with sedimentation rates suitably high to avoid major corrections for bioturbation effects suggest that the ventilation rate of the deep Pacific Ocean has remained nearly the same throughout Holocene time. Further, there is no suggestion that the rate was slower during the period of major glacial retreat. These results confirm that the changes in atmospheric14C/C ratio over the last 10000 years owe their origin to radiocarbon production rate changes. 相似文献
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Qu Shaohou 《大气科学进展》1992,9(1):46-52
The Antarctic ozone hole which was discovered in the mid 1980s has caused much attention from the scientists and politicians throughout the world.For the formation of the Antarctic ozone hole, most scientists believe that the man-made chemical materials such as CFCs etc. are main cause. On the other hand, the electrochemistry-dynamics theory presented by Wei (Guang Ming Daily Dec. 11, 1990) two years ago has also caused some attention.In the paper the data of ozone, solar activity meteorology over Antarctica have been used for statistical analyti-cal studies. Our results present some new evidence to support Wei's theory. However the influence of the human activ-ities can never be slighted. 相似文献
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Effect of the Interaction of Different Scale Vortices on the Structure and Motion of Typhoons 总被引：13，自引：1，他引：13
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