Qian Yongfu  Wang Qianqian 《大气科学进展》1996,13(3):383-398

The effects of the land-sea contrast and the topography on the climatic properties are simulated in this paper by use of a p-σ incorporated coordinate system model in a zonal domain. In this paper we firstly discuss the statistical features of the model and find that the capability of the model is stable, with the same land-sea distribution and topography seven monthly mean climate states are close to one another, their variance is even less than the initial one. Secondly, we focally discuss the effects of the land-sea contrast and the topography on the modeled climate fields. It is pointed out that the land-sea contrast and the topography influence the atmosphere mainly through the heating effect and the former has larger influences on the simulated large scale climate fields than the latter. Supported by the National Key Project of Fundamental Research “Climate Dynamics and Climate Prediction Theory” and the National Natural Science Foundation of China.  相似文献   

三峡坛子岭单点地面矢量风分析   总被引：1，自引：0，他引：1       下载免费PDF全文

沈铁元  陈少平  陈正洪  杨维军  毛以伟 《气象》2003,29(3):12-16

利用UVW三轴风速仪三峡坛子岭单点地面风观测资料分析了三峡坝区地面风速量值、风向风速出现频率分布、风的日变化规律等，并根据这些观测资料、结合一些地形风理论知识和观测现象推测了三峡坛子岭附近地面风平面流场特征，从而揭示了河道地形回流风这一特殊小地形下的局地风现象。三峡坛子岭附近地面的这种回流风尺度在百米到千米量级，与由于地形热力因子引起的山地风不同，是由于小地形的动力作用引起的，其风向与长江河道引导的山地风相反。  相似文献   

鲁北沿海强对流天气多发的成因及临近预报     

山义昌  刘桂才  张秀珍  高晓梅 《气象》2003,29(11):20-24

潍坊北部系海陆交界处，由于地理因素，经常形成海陆风锋，当海陆风锋与其他天气系统叠加，会使系统加强，天气剧烈，在夏季是鲁北强对流天气多发的重要原因。一次冷锋过程分析说明与海陆风锋叠加能形成强锋区，锋区上的D、ζ有利于上升运动，与之对应的地面高能区为系统提供了能源。通过对鲁北21个强对流天气个例研究，建立了冰雹云移动路径的临近预报方程。这些研究对鲁北多发强对流天气的成因及冰雹落区预报具有参考价值。  相似文献   

Vegetation response to rapid climate change in central europe during the past 140,000 yr based on evidence from the Füramoos pollen record     

Ulrich C Müller  J.örg ProssErhard Bibus 《Quaternary Research》2003,59(2):235-245

The response of Central European vegetation to rapid climate change during the late Quaternary period (Eemian to Holocene) is assessed by data from the new pollen record of Füramoos, southwestern Germany. This record represents the longest late Quaternary pollen record north of the Alps as currently known. Its high degree of completeness allows detailed correlations with Greenland ice cores and sea-surface temperature records from the North Atlantic. Our data show that if climate deteriorations were not long or severe enough to extirpate refugia of arboreal taxa north of the Alps such as during marine oxygen isotope stage (MIS) 5 (i.e., Würm Stadial A, Stadial B, and Stadial C), reforestation with the onset of warmer conditions in Central Europe occurred on a centennial scale. If arboreal taxa became completely extinct north of the Alps such as during MIS 4 (i.e., Würm Stadial D), several thousand years were necessary for the reimmigration from refugia situated in regions south of the Alps. Thus, Dansgaard-Oeschger interstades (DOIS) 24 to 20 and 15 to 11 are expressed in Central European pollen records, whereas DOIS 19 to 16 are not recorded due to migration lags.  相似文献   

ENSO 循环各阶段东亚夏季风特征的诊断研究   总被引：2，自引：6，他引：2  

陈月娟  简俊  周任君 《高原气象》2002,21(5):441-446

利用NCEP／NCAR再分析资料和NCAR海温资料及中国测站地温资料，对ENSO循环不同阶段东亚夏季风强弱变化进行了分析．并从此期间的海陆热力差异和季风低压变化来探讨海温异常对东亚夏季风的影响，结果表明：东亚夏季风指数有明显的年际变化和年代际变化，且与赤道东太平洋SST有较好的负相关关系，其中又以与三个月前的海温变化关系最好．在Ninol 2区为冷、暖水之后的三个月中，冷水期对应的东亚夏季风指数大于暖水期对应的东亚夏季风指数，东亚夏季风比暖水期强。赤道东太平洋SST变化期间亚洲大陆的地面温度和地面气压也有明显变化，这是引起ENSO不同阶段东亚夏季风变化的主要原因。  相似文献   

厄尔尼诺现象的构造基础与激发因素   总被引：9，自引：1，他引：9       下载免费PDF全文

杨学祥 《地震工程学报》2002,24(4):367-370

北太平洋对北极的半封闭状态和南太平洋对南极的开放状态是厄尔尼诺事件发生的构造基础，它导致北太平洋海表热能的积累和周期性向南太平洋输送，强潮汐振荡和火山喷发是其激发因素。  相似文献   

Sea-breeze-initiated rainfall over the east coast of India during the Indian southwest monsoon   总被引：1，自引：0，他引：1  

Matthew Simpson  Hari Warrior  Sethu Raman  P. A. Aswathanarayana  U. C. Mohanty  R. Suresh 《Natural Hazards》2007,42(2):401-413

Sea-breeze-initiated convection and precipitation have been investigated along the east coast of India during the Indian southwest monsoon season. Sea-breeze circulation was observed on approximately 70–80% of days during the summer months (June–August) along the Chennai coast. Average sea-breeze wind speeds are greater at rural locations than in the urban region of Chennai. Sea-breeze circulation was shown to be the dominant mechanism initiating rainfall during the Indian southwest monsoon season. Approximately 80% of the total rainfall observed during the southwest monsoon over Chennai is directly related to convection initiated by sea-breeze circulation.  相似文献   

Local diurnal upwelling driven by sea breezes in northern Monterey Bay     

C.B. Woodson  D.I. Eerkes-Medrano  A. Flores-Morales  M.M. Foley  S.K. Henkel  M. Hessing-Lewis  D. Jacinto  L. Needles  M.T. Nishizaki  J. O’Leary  C.E. Ostrander  M. Pespeni  K.B. Schwager  J.A. Tyburczy  K.A. Weersing  A.R. Kirincich  J.A. Barth  M.A. McManus  L. Washburn 《Continental Shelf Research》2007

Sea breezes often have significant impacts on nearshore physical and biological processes. We document the effects of a diurnal sea breeze on the nearshore thermal structure and circulation of northern Monterey Bay, California, using an array of moorings during the summer upwelling season in 2006. Moorings were equipped with thermistors and Acoustic Doppler Current Profilers (ADCPs) to measure temperature and currents along the inner shelf in the bay. Temperature and current data were characteristic of traditional regional scale upwelling conditions along the central California coast during the study period. However, large diurnal fluctuations in temperature (up to 5 °C) were observed at all moorings inshore of the 60-m isobath. Examination of tidal, current, temperature, and wind records revealed that the observed temperature fluctuations were the result of local diurnal upwelling, and not a result of nearshore mixing events. Westerly diurnal sea breezes led to offshore Ekman transport of surface waters. Resulting currents in the upper mixed layer were up to 0.10 m s⁻¹ directed offshore during the afternoon upwelling period. Surface water temperatures rapidly decreased in response to offshore advection of surface waters and upwelling of cold, subsurface water, despite occurring in the mid-afternoon during the period of highest solar heat flux. Surface waters then warmed again during the night and early morning as winds relaxed and the upwelling shadow moved back to shore due to an unbalanced onshore pressure gradient. Examination of season-long, moored time series showed that local diurnal upwelling is a common, persistent feature in this location. Local diurnal upwelling may supply nutrients to nearshore kelp beds, and transport larvae to nearshore habitats.  相似文献   

珠峰绒布河谷大气边界层结构的数值模拟   总被引：2，自引：6，他引：2  

朱凌云  张美根  马舒坡  李鹏  邹捍  李爱国 《高原气象》2007,26(6):1208-1213

利用中尺度气象模式RAMS对2006年6月12～16日珠峰绒布河谷地区大气边界层结构进行了模拟,并将模拟的风温时空分布与风廓线仪LAP3000的观测资料进行了对比分析.结果表明,绒布河谷地区的局地环流具有明显的日变化(午后至夜间盛行山风,可持续12h,且风速较大;在山风盛行期间,山风的影响高度可达400～700m左右),其中下垫面不均匀性导致的温度差异是引起局地环流的主要因素;RAMS模式较好地反映了绒布河谷地区局地环流的时空变化特征.  相似文献   

Impact of surface heterogeneity on a buoyancy-driven convective boundary layer in light winds     

Dominique Courault  Philippe Drobinski  Yves Brunet  Pierre Lacarrere  Charles Talbot 《Boundary-Layer Meteorology》2007,124(3):383-403

Land-use practices such as deforestation or agricultural management may affect regional climate, ecosystems and water resources. The present study investigates the impact of surface heterogeneity on the behaviour of the atmospheric boundary layer (ABL), at a typical spatial scale of 1 km. Large-eddy simulations, using an interactive soil–vegetation–atmosphere surface scheme, are performed to document the structure of the three-dimensional flow, as driven by buoyancy forces, over patchy terrain with different surface characteristics (roughness, soil moisture, temperature) on each individual patch. The patchy terrain consists of striped and chessboard patterns. The results show that the ABL strongly responds to the spatial configuration of surface heterogeneities. The stripe configuration made of two patches with different soil moisture contents generates the development of a quasi- two-dimensional inland breeze, whereas a three-dimensional divergent flow is induced by chessboard patterns. The feedback of such small-scale atmospheric circulations on the surface fluxes appears to be highly non-linear. The surface sensible and latent heat fluxes averaged over the 25-km² domain may vary by 5% with respect to the patch arrangement.  相似文献