NUMERICAL STUDY ON FUNCTIONS AFFECTING TROPICAL CYCLONE STRUCTURE AND MOTION^*          下载免费PDF全文

Chen Lianshou  Luo Zhexian 《Acta Meteorologica Sinica》1998,12(4):504-512

By using a beta-plane quasigeostrophic barotropic model,four numerical experiments with integration time more than five days are performed.Results show that the vorticity advection term and beta term are two basic factors significantly affecting tropical cyclone structure and motion.  相似文献   

Advection of plumes in mantle flow: implications for hotspot motion, mantle viscosity and plume distribution   总被引：8，自引：0，他引：8  

Bernhard Steinberger  & Richard J. O'Connell 《Geophysical Journal International》1998,132(2):412-434

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不同下垫面湍流输送计算方法的研究   总被引：9，自引：0，他引：9       下载免费PDF全文

刘树华  刘和平 《应用气象学报》1996,7(2):229-237

文章应用三种不同下垫面近地面层风速和温度梯度资料，代入风速和温度廓线公式，迭代求得感热通量及热量交换系数。确定Kh /Kw与稳定参数ξ的关系式。分别利用空气动力学方法和波文比能量平衡法计算潜热通量，并进行了比较。  相似文献   

一次爆发性气旋的发展与湿位涡关系的研究   总被引：13，自引：3，他引：13  

牛宝山  丁治英  王劲松 《南京气象学院学报》2003,26(1):8-16

通过对一次陆地爆发性气旋的数值模拟与湿位涡的诊断分析发现，气旋的爆发与湿位涡的平流关系密切，气旋的发展并不是在湿位涡中心位于气旋上空时才开始，而是当湿位涡中心位于气旋的后部，并在200hPa对下有明显的倒圆锥形下伸区时，才有利于气旋的发展。当湿位涡中心位于气旋上空时，气旋发展开始减慢。湿位涡局地变化的大小与水平方向位涡梯度的大小有关。湿斜压位涡负值区的上下贯通与气旋发展也有明显的关系。  相似文献   

咸阳机场两次能见度突变天气的对比分析     

高洁  刘仙婵 《沙漠与绿洲气象(新疆气象)》2003,26(2):17-18

对咸阳机场的两次能见度突然转差的天气进行分析比较，探讨该类形势下大雾的成因及周边地理环境对成雾的影响，并对此类天气的预报思路提出几点建议。  相似文献   

Modelling of evaporation in a sparse millet crop using a two-source model including sensible heat advection within the canopy     

M. R. Lund  H. Soegaard 《Journal of Hydrology》2003,280(1-4):124-144

During two successive growing seasons meteorological measurements were made in a pearl millet field in the Sahel to investigate the evaporation process in relation to crop growth. The evaporation was measured by eddy correlation and simulated using the Shuttleworth Wallace (SW) model [Q. J. R. Meteorol. Soc. 111 (1985) 839–855]. To take sun height and multi-layer scattering into account a radiation balance model was formulated. The model indicates that partitioning of the net radiation between the vegetation and the soil may be estimated (r²=0.94) from the fraction of diffuse radiation, the leaf area index and an attenuation coefficient, but that the attenuation coefficient may not be similar in different locations. To solve the SW-model with respect to the soil resistance an iterative solution was employed with the total evaporation estimated from the Bowen-ratio calculated from eddy correlation measurements. The procedure made it possible to derive stable estimates of soil resistance at soil evaporation rates down to 25 W m⁻². The soil resistance was found to be in accordance with evaporation through a dry surface layer. The SW-model indicates, that advection of sensible heat from the dry soil to the plants, increases transpiration considerably. This will cause management techniques, such as mulching and dry farming, aimed at reducing soil evaporation to be less effective than might be anticipated. The effects of raising the leaf area index to improve the microclimate is discussed in relation to management of the available water and crop security.  相似文献   

JFNK方法在求解全隐式一维非线性平流方程中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

陈长胜  纪立人  陈嘉滨 《大气科学》2007,31(5):963-972

JFNK(Jacobian-free Newton-Krylov)方法是由Newton迭代方法和Krylov子空间迭代方法构成的嵌套迭代方法。作者以全隐式差分的一维非线性平流方程（亦称无粘Burgers方程）探讨采用全隐式格式计算的必要性和JFNK方法的有效性。模拟结果表明, 隐式结果比显式和半隐式结果在稳定度和精度方面较大的优越性, 特别是模拟气流强的系统以及要素空间分布具有较大梯度的系统。  相似文献   

Divergence of turbulent fluxes in the surface layer: case of a coastal city     

G. Pigeon  A. Lemonsu  C. S. B. Grimmond  P. Durand  O. Thouron  V. Masson 《Boundary-Layer Meteorology》2007,124(2):269-290

This study quantifies the processes that take place in the layer between the mean building height and the measurement level of an energy balance micrometeorological tower located in the dense old core of a coastal European city. The contributions of storage, vertical advection, horizontal advection and radiative divergence for heat are evaluated with the available measurements and with a three-dimensional, high-resolution meteorological simulation that had been evaluated against observations. The study focused on a summer period characterized by sea-breeze flows that affect the city. In this specific configuration, it appears that the horizontal advection is the dominant term. During the afternoon when the sea breeze is well established, correction of the sensible heat flux with horizontal heat advection increases the measured sensible heat flux up to 100 W m⁻². For latent heat flux, the horizontal moisture advection converted to equivalent latent heat flux suggests a decrease of 50 W m⁻². The simulation reproduces well the temporal evolution and magnitude of these terms.  相似文献   

On the Factors Controlling the Snow Surface and 2-m Air Temperatures Over the Arctic Sea Ice in Winter     

Timo?VihmaEmail author  Roberta?Pirazzini 《Boundary-Layer Meteorology》2005,117(1):73-90

Factors controlling the magnitudes of, and short-term variations in, the potential temperatures of the snow surface and the air at the height of 2 m θ_S and θ_{2 m} over Arctic sea ice in winter are analysed. The study addresses the winters of 1986–1987 and 1987–1988, and is based on the temperature, wind, and cloud observations made by Russian drifting ice stations. It also relies on the ERA40 re-analyses of the European Centre for Medium-Range Weather Forecasts, which were utilised to calculate the lateral heat advection at the sites of the ice stations. The cloud cover and wind speed were more important than the heat advection in controlling the magnitudes of θ_{2 m} and θ_S, while on a time scale of 24 h, during steady forcing conditions, the heat advection was the most important factor affecting the changes in θ_S and θ_{2 m}. During changing conditions, and considering individual factors separately, the monthly mean 24-h temperature changes were less than ± 5 °C: the effect of the cloud cover was the largest, and that of the heat advection was the smallest. When simultaneous changes in the three factors were analysed, the seasonal mean temperature changes were even of the order of ±15 °C, with the strongest warming events exceeding 35 K in a single day. The difference θ_S − θ_{2 m} reached its lowest seasonal mean values during conditions of clear skies (−1.3 °C), light winds (−1.3 °C) and warm-air advection (−0.8 °C). θ_S and θ_{2 m} followed each other closely, even during major synoptic-scale temperature variations.  相似文献   

Variations in the advection of Calanus finmarchicus onto the Faroe Shelf     

Gaard  E.; Hansen  B. 《ICES Journal of Marine Science》2000,57(6):1612-1618

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