广州市37℃以上酷热天气形势及相关要素分析   总被引：21，自引：3，他引：18  

黄忠  熊亚丽  林良勋 《气象》2005,31(7):24-27

对1951年以来广州市出现的37℃以上的酷热天气的形势特征和广州气象要素进行分析,发现这类天气多发生在地面气压场西北高东南低的形势之下,与副热带高压和热带气旋活动关系密切,二者的共同作用使广州附近多数情况下出现下沉气流。结果还表明,广州地面和低空吹偏北气流更易出现酷热天气,酷热天气还与前期的气温和降水等要素关系密切。  相似文献   

强热带风暴蒲公英引起太湖强风的成因分析   总被引：1，自引：0，他引：1  

李法然 《气象》2005,31(8):57-61

0407号强热带风暴(蒲公英)在浙江省乐清市登陆数小时后,300km外的太湖地区狂风大作,位于太湖南岸的太湖自动站7月3日13时极大风力达29.3m·s-1,超过了风暴近中心及途经地区测站的最大风速。这在湖州市历史记录中是从未有过的异常现象,在台风记录中也属罕见。  相似文献   

影响海南的热带气旋气候特征及其与ENSO的关系   总被引：12，自引：1，他引：11  

吴慧 《气象》2005,31(12):61-64

利用1949～2003年资料,统计了影响和登陆海南热带气旋频数的时空分布特征、初、终期分布,并探讨了ENSO事件对海南省热带气旋的影响和2004年无热带气旋影响海南的原因.指出ENSO事件与海南省热带气旋活动具有显著的相关性,暖事件年有利于影响和登陆热带气旋偏少、初旋偏晚,冷事件年则相反.但ENSO事件与终旋日期相关不显著.  相似文献   

Using TOPMODEL towards identifying and modelling the hydrological patterns within a headwater,humid, tropical catchment     

HELENA MOLIOV  MICHEL GRIMALDI  MIKE BONELL  PIERRE HUBERT 《水文研究》1997,11(9):1169-1196

Increasing pressure on the tropical environment requires a more thorough understanding of hydrological processes as part of reconciling the conflicting demands of economic development vis-à-vis sustainable land management. Using TOPMODEL, a physically based semi-distributed topohydrological model, we test its validity in modelling the stream flow dynamics (hydrograph) in a 1 ha tropical rainforest catchment in French Guiana. Another objective is through field validation of TOPMODEL to ascertain possible runoff generation mechanisms. The field validation of the temporal and spatial hydrodynamics across a rainfall–runoff event reveals that TOPMODEL may be suited for applications to this particular tropical rainforest environment; in fact, this is possibly the first successful application of such a model within the humid tropics. The main reasons why the model was successful are the presumed low hydraulic conductivities of the subsoil, coupled with the absence of an additional deep groundwater body, the contribution from which has caused difficulties in application of topographically, ‘physically’ based runoff models elsewhere in the humid tropics. © 1997 John Wiley & Sons, Ltd.  相似文献   

FORMATION AND STRUCTURAL EVOLUTION OF INITIAL DISTURBANCE OF TYPHOON FUNG-WONG (2008)     

江佳  朱佩君  江洁 《热带气象学报(英文版)》2016,22(1):1-10

The formation of a tropical cyclone is the result of a process in which an initial disturbance evolves into a warm-core low-pressure system; however, the origin of the initial disturbance and the features of the initial fields are overlooked in most existing theories. In this study, based on FY-2C brightness temperature data and the Japan reanalysis dataset, the origin and evolution of the tropical disturbance that became Typhoon Fung-Wong (2008) were examined. The results demonstrated that the initial disturbance emerged within a saddle-type field with large vertical tropospheric wind shear. The vertical wind shear decreased with the adjustment of the upper circulation; moreover, accompanied by convection over the warm section around the upper cold vortex, it provided favorable thermal and dynamic conditions for the development of a tropical vortex. During its development, the zone of associated positive relative vorticity strengthened and descended from the mid-troposphere to lower levels. This rapid strengthening of lower-level vorticity was due to increasing convergence related to the intensification of the pressure gradient southwest of the subtropical high. This indicated that the upper cold vortex and West Pacific subtropical high played very important roles in this case.  相似文献   

西双版纳热带季节雨林细根周转的研究   总被引：4，自引：0，他引：4  

房秋兰  沙丽清 《山地学报》2005,23(4):488-494

研究了季节雨林0~20 cm土层中≤2 mm细根的生物量、分解量、死亡量、生长量和周转率,并比较了0~10 cm和10~20 cm土层细根生物量的差异。结果表明:0~10 cm的细根生物量明显多于10~20 cm的细根生物量;在0~20 cm土层中,季节雨林活细根和死细根生物量分别为5 418 kg.hm-2和707 kg.hm-2;细根生物量的季节变化显著,其中活细根生物量的最大值出现在5月,最小值出现在8月;年分解量、年死亡量、年生长量和年周转率分别为391 kg.hm-2,1 061 kg.hm-2,3 776 kg.hm-2和0.70 times.a-1。  相似文献   

Hurricanes and tropical storms: A necessary evil to ensure water supply?          下载免费PDF全文

Meijing Zhang  Xing Chen  Mukesh Kumar  Marco Marani  Michael Goralczyk 《水文研究》2017,31(24):4414-4428

Several parts of the globe including Southeast North America, the Caribbean, Southeast Asia, Australia, and China are often hit by hurricanes and tropical storms (HTSs), which can deliver a large amount of rainfall within a period of a few days. Although HTSs are mostly studied as disaster agents, considering that they occur during the period when water supply systems are generally depleted, it is important to ascertain their potential contributions toward sustaining water supply. Using the Lake Michie–Little River reservoir system that supplies water to the city of Durham (North Carolina) as a representative test case, we implemented an integrated watershed and reservoir management model, supported by publicly available observations, to evaluate the extent to which HTSs impact water storages. Results indicate that HTSs can have a significant impact on reservoir water storage, with their effects being felt for more than a year for some storms. The impact on reservoir water storage is identified to be primarily controlled by 3 factors, namely, streamflow response size from HTSs, storage in the reservoir right before the event, and streamflow succeeding the event response to HTS (henceforth referred as postevent streamflow). Although the impact of streamflow response size on water storage is generally proportional to its magnitude, initial water storage in the reservoir and postevent streamflow have a nonmonotonic influence on water storage. As all the 3 identified controls are a function of antecedent hydrologic conditions and meteorological forcings, these 2 factors indirectly influence the impact of HTS on water storage in a reservoir. The identification of controlling factors and assessment of their influence on reservoir response will further facilitate implementation of more accurate estimation and prediction frameworks for within‐year reservoir operations.  相似文献   

The effects of tropical storm Dennis on coastal phytoplankton     

Stephan I. Zeeman 《Estuarine, Coastal and Shelf Science》1985,20(4):403-418

The effects of tropical storm Dennis were documented in the coastal waters of South Carolina during August 1981. Phytoplankton photosynthesis vs. irradiance curves showed initial depression of the parameter a followed by three- to five-fold increase of both a and the asymptotic maximum rate of photosynthesis P_m^B. Productivity rates were depressed in most samples immediately after the storm. Surface samples at the inshore stations were around 50 mg C m^?3 h^?1 at saturating light intensities, while the offshore station rates were around 10 mg C m^?3 h^?1. After a 10-day lag these rates had increased to about 200 mg C m^?3 h^?1 inshore and 75 mg C m^?3 h^?1 offshore. These changes are thought to be primarily caused by changes in species composition. Some of the dominant diatom species changed and dinoflagellate species were introduced. No significant changes in nutrient concentrations were observed. Transient depressions of water temperature, salinity and light intensity may have contributed to the observed changes.  相似文献   

A 3—Dimensional baroclinic circulation model of the tropical and northern Pacific     

Cai Yi  Li Yu-xiang 《中国海洋湖沼学报》1997,15(1):70-79

A primitive equation 3-dimensional baroclinic ocean model without the rigid-lid approximation is described. The horizontal resolution is 2.5°×2° and the vertical variations of the velocity components are resolved by 6 layers. In order to increase the allowable integration time step which is constrained by stability requirements, the vertically integrated continuity equation is linearized and both the pressure gradient terms and the Coriolis terms in the momentum equations are finite-differenced semi-implicitly. The model is applied to simulate the circulation as well as the free surface elevation and temperature patterns in the tropical and northern Pacific Ocean in both summer and winter using the wind and temperature data at the 1000 mb pressure level as input to the model. The computed results are in general consistent with observed patterns. In particular, it is shown that the positions of the meandering axis of the Kuroshio in summer and winter are markedly different. This work was supported by the Hong Kong Polytechnic University Research Grant No. 340/854.  相似文献   

A 3-DIMENSIONAL BAROCLINIC CIRCULATION MODEL OF THE TROPICAL AND NORTHERN PACIFIC     

蔡怡  李毓湘 《中国海洋湖沼学报》1997,(1)

ImODUcrIONTheoceanisanimPoftantcomPonentofourenvironment,affchthedimatethroughairseaintCraCtions,anexamPleofwhichistheanomalousworkldirnatecausedbytheElNffoduetoanomaloustemPeratuasofthePadricthen,offersincmising1ydriportantresounatornankind,butbeauseofthescardtyoffiekldata,ourknowledgeofthedynandesofthevariousproanesthatoccurintheocean(eSpedallyinthedeepsea)isstilifarfromcomplete.WiththerapiddeveopmentofhighspedcomPutersandnumericalmathematics,numericalsimulationsarenowwidelyusedtocomP…  相似文献