基于情景模拟的天津市滨海新区2020年暴雨内涝风险评估   总被引：4，自引：0，他引：4  

胡蓓蓓  周俊  王军  许世远  孟伟庆 《地理科学》2012,(7):846-852

基于多灾种复合动态风险评估理论,依据滨海新区2020年人口规划、土地利用规划以及社会经济发展计划,根据地面沉降和海平面上升预测结果设计了最不利、适中和最理想化三种情景;在此基础上,自行开发了基于GIS的洪水淹没区计算模块,模拟计算不同重现期暴雨内涝的淹没范围、淹没深度及淹没损失。结果表明:2020年,发生1 000 a一遇、200 a一遇和50 a一遇暴雨时,在最不利的情景一下:天津市滨海新区分别将有32.73%,29.34%和26.01%的土地不同程度受淹,受淹人口分别为338万、305万和264万,淹没损失分别达220.89亿元、181.39亿元和139.12亿元。  相似文献   

库姆塔格沙漠春季近地面风场、温度场特征   总被引：1，自引：1，他引：0  

吕萍  董治宝 《中国沙漠》2012,32(2):442-446

 利用中尺度区域预报模式系统对库姆塔格沙漠及其周边地区春季近地层风场与温度场分布特征进行了模拟和分析。结果发现,受青藏高原地形影响,偏北气流向南运行在途经库姆塔格沙漠的过程中发生3个分支:①在沙漠东部气流逐渐转变为西北风吹向甘肃省;②中西部气流以较强的东北风流向塔克拉玛干沙漠;③另一部分气流继续顺势南下流入青海省。沙漠区域温度从北向南逐渐降低,在青海省的边界上出现一个低温带,然后温度又开始增加。  相似文献   

近540 a东亚夏季海平面气压场的重建及其与数值模拟的比较   总被引：1，自引：0，他引：1  

李茜  魏凤英  李栋梁 《中国沙漠》2012,32(4):1017-1024

 基于中国东部地区旱涝分布和东亚夏季海平面气压存在密切关系的基础上,利用1470—2008年中国东部地区旱涝等级资料、1850—2008年东亚夏季海平面气压资料,运用主成分回归的方法重建了1470—2008年的东亚地区夏季海平面气压场,并对重建结果进行了检验,同时对1470—2008年东亚夏季海平面气压重建场和FGOALS_gl数值模式模拟的海平面气压场进行了对比分析。结果表明:①1850—2008年重建的东亚夏季海平面气压场在东亚夏季风关键区（中国内陆地区以及西北太平洋部分地区）重建效果相对于其他地区要好。②1470—2008年重建的东亚夏季海平面气压场主要存在高纬与中纬气压差异、海洋与陆地差异的两种空间分布型;1470—1999年FGOALS_gl数值模拟的东亚夏季海平面气压主要体现了海陆气压差异。③根据重建的东亚夏季海平面气压场定义的1470—2008年东亚夏季风指数的演变具有明显的阶段性,16世纪中期到17世纪初东亚夏季风偏强,17世纪偏弱,18世纪经历了“弱-强-弱-强-弱”的变化,19世纪则是“强-弱-强-弱”的变化,20世纪是明显的“弱-强-弱”变化。而1470—1999年数值模拟的东亚夏季风指数序列与重建序列的主要差异出现在16世纪末和18世纪末,两者的变化趋势相反,其他时段的变化趋势基本一致。  相似文献   

云南降水中稳定同位素变化的模拟和比较   总被引：6，自引：0，他引：6  

章新平  关华德  孙治安  孙广禄  张新主  吴华武 《地理科学》2012,(1):121-128

利用MUGCM的模拟,云南地区日、月、年时间尺度下降水中稳定同位素的变化、降水量效应以及δD/δ18O之间的关系被分析。无论是在日时间尺度下还是在月、年时间尺度下,降水同位素均存在显著的降水量效应。与实测结果相比,模拟的降水中δ18O与降水量之间具有更强的相关性。对于单站而言,蒙自站和腾冲站的大气水线被较好地模拟。但在思茅站和昆明站,模拟结果未能准确再现实际降水中δD与δ18O的关系,模拟的大气水线斜率比实测结果偏高。这意味着,在云南这个特殊的地区,模式可能高估了HDO的贫化。  相似文献   

The Nichols' Relief Model of the United States     

《The Journal of geography》2012,111(2):96-99

Abstract

The agricultural system in West Pakistan is largely subsistence-oriented, and extensive areas are devoted to produce the low-value crops. Only a small portion of the total cropped area is used to raise cash crops. However, there are regional differences in cropland use in the province. The study focuses on regional variations in the cropping patterns in West Pakistan by establishing the crop combination areas. The crop combination areas also point out a land-use distinction between the areas. Also, the changes in some of the important crops in terms of their land occupancy in the area during the fifteen-year period have been analyzed.  相似文献   

The tropical intraseasonal oscillation in SAMIL coupled and uncoupled general circulation models   总被引：4，自引：1，他引：3  

杨静  包庆  王晓聪  周天军 《大气科学进展》2012,29(3):529-543

Simulations of tropical intraseasonal oscillation(TISO) in SAMIL,the Spectral Atmospheric Model from the Institute of Atmospheric Physics(IAP) State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) coupled and uncoupled general circulation models were comprehensively evaluated in this study.Compared to the uncoupled model,the atmosphere-ocean coupled model improved the TISO simulation in the following aspects:(1) the spectral intensity for the 30-80-day peak eastward periods was more realistic;(2) the eastward propagation signals over western Pacific were stronger;and(3) the variance distribution and stronger signals of Kelvin waves and mixed Rossby gravity waves were more realistic.Better performance in the coupled run was assumed to be associated with a better mean state and a more realistic relationship between precipitation and SST.In both the coupled and uncoupled runs,the unrealistic simulation of the eastward propagation over the equatorial Indian Ocean might have been associated with the biases of the precipitation mean state over the Indian Ocean,and the unrealistic split of maximum TISO precipitation variance over the Pacific might have corresponded to the exaggeration of the double Intertropical Convergence Zone(ITCZ) structure in precipitation mean state.However,whether a better mean state leads to better TISO activity remains questionable.Notably,the northward propagation over the Indian Ocean during summer was not improved in the mean lead-lag correlation analysis,but case studies have shown some strong cases to yield remarkably realistic northward propagation in coupled runs.  相似文献   

沙尘暴过程中沙尘对流层-平流层输送的数值模拟初步分析     

姜学恭  陈受钧  顾润源  陈磊 《气象学报》2012,70(6):1223-1234

在初步明确东亚沙尘气溶胶对流层-平流层输送监测事实的基础上,利用观测资料、NCEP再分析资料以及基于中尺度天气模式MM5的数值模拟方法,对一次蒙古气旋沙尘暴过程中沙尘对流层-平流层输送问题进行了初步分析.结果表明:斜压不稳定是本次蒙古气旋发展的主要强迫要素,伴随气旋发展成熟,高空切断低涡的形成引导高空急流下落并诱发对流层顶折叠和高空位涡下传.对流层顶折叠区呈漏斗状,底部达500 hPa左右.高空急流产生近似垂直的下落,并在高空切断低涡的南侧和东侧达到最强.在对流层顶折叠区周边的300-500 hPa,上升气流与低涡区偏西、偏南、偏东气流叠加,或水平横穿折叠的对流层顶,或斜升并准垂直地穿过下落的对流层顶到达平流层,且随时间的推移,空气质点能够进一步抵达平流层中部(100 hPa).轨迹分析表明,沙尘天气区对流层低层的空气质点在气旋涡旋上升气流的驱动下呈气旋式盘旋上升,并在对流层高层形成分支,一支穿过对流层顶到达平流层,并在平流层向下游进行反气旋式螺旋运动,另一支则留在对流层高层并向下游进行准水平的气旋式螺旋运动.在高空位涡下传过程中,主要产生平流层到对流层的净输送;高空位涡停止下传之后则出现对流层到平流层的净输送,且强度随时间呈指数型增长.这一特征有利于形成更强的沙尘对流层平流层输送.  相似文献   

Circulation Around Luzon Strait in September as Inferred from CTD,Argos and Argo Measurements and a Generalized Topography-Following Ocean Model     

《大气与海洋》2012,50(4):40-58

The hydrography, wind, Argos and Argo measurements in the areas surrounding Luzon Strait were collected. Based on the hydrographic data obtained during September 1994, the improved Princeton Ocean Model using a generalized topography-following coordinate system together with a modified inverse method was applied to study the circulation in September. Observations and the diagnostic simulation produce a consistent circulation pattern, and the main dynamical features can be summarized as follows. (1) The Kuroshio has two branches with the main Kuroshio existing above 800 m depth and the western part existing above 400 m depth. The western branch of the Kuroshio leaves the main current near 20.5°N, then flows northwestward through Luzon Strait and finally flows out of the northern boundary southwest of Taiwan, consistent with the trajectory of Argos drifters. (2) The non-linear term is important and cannot be neglected in the momentum equations in the northern part of Luzon Strait under the baroclinicity field. Using non-linear dynamics, the westward intrusion of the Kuroshio into the northern part of Luzon Strait is more curved than when using linear dynamics. However, the non-linear term is smaller and so negligible around Luzon Strait under the homogeneous density field. (3) In the area from 117°E to 119°E and from 20.2°N to 21.7°N, an anticyclonic eddy appears east of Dongsha Islands. (4) At depths above 400 m, the circulation is mainly dominated by the basin-scale cyclonic gyre. (5) In the computational domain west of 121°E, the circulation below 800 m is mainly dominated by the basin-scale anticyclonic gyre. (6) The South China Sea water flows eastward across Luzon Strait in the middle layers, then turns cyclonically, finally flowing northward into the region east of Taiwan Island, which is qualitatively in agreement with the trajectories of Argo floats at about 1000 m depth in the area east of 121°E.

RÉSUMÉ?[Traduit par la rédaction] Nous avons rassemblé l'hydrographie, le vent, les Argo et les mesures Argo dans les régions avoisinant le détroit de Luçon. Sur la base des données hydrographiques relevées durant le mois de septembre 1994, nous avons appliqué le modèle océanique amélioré de Princeton utilisant un système de coordonnées « suivant le terrain » généralisé de pair avec une méthode inverse modifiée pour étudier la circulation en septembre. Les observations et la simulation diagnostique produisent une configuration de circulation cohérente dont on peut résumer comme suit les principales caractéristiques dynamiques. (1) Le Kuroshio possède deux branches : le Kuroshio principal existant au-dessus d'une profondeur de 800 m et la partie ouest existant au-dessus d'une profondeur de 400 m. La branche ouest du Kuroshio quitte le courant principal aux environs de 20,5°N et se dirige vers le nord-ouest à travers le détroit de Luçon pour finalement franchir la limite nord du détroit au sud-ouest de Taïwan, ce qui correspond à la trajectoire des bouées dérivantes Argos. (2) Le terme non linéaire dans les équations est important et ne peut pas être considéré négligeable de quantité de mouvement dans la partie nord du détroit de Luçon dans le champ de baroclinité. Lorsqu'on utilise la dynamique non linéaire, l'intrusion vers l'ouest du Kuroshio dans la partie nord du détroit de Luçon est plus incurvée que lorsqu'on utilise la dynamique linéaire. Cependant, le terme non linéaire est plus petit et donc négligeable autour du détroit de Luçon dans le champ de densité homogène. (3) Dans la région allant de 117°E à 119°E et de 20,2°N à 21,7°N, un remous anticyclonique apparaît à l'est des îles Dongsha. (4) Aux profondeurs inférieures à 400 m, la circulation est principalement dominée par le gyre cyclonique à l’échelle du bassin. (5) Dans le domaine de calcul à l'ouest de 121°E, la circulation sous 800 m est principalement dominée par le gyre anticyclonique à l’échelle du bassin. (6) Les eaux de la mer de Chine méridionale s’écoulent vers l'est à travers le détroit de Luçon dans les couches intermédiaires, puis tournent de façon cyclonique pour finalement s’écouler vers le nord dans la région à l'est de l’île Taïwan, ce qui, qualitativement, s'accorde avec la trajectoire des flotteurs Argo à environ 1000 m de profondeur dans la région à l'est de 121°E.  相似文献   

Observational and Modeling Studies of Impacts of the South China Sea Monsoon on the Monsoon Rainfall in the Middle-Lower Reaches of the Yangtze River During Summer   总被引：1，自引：0，他引：1       下载免费PDF全文

JIN Lijun  ZHAO Ping 《Acta Meteorologica Sinica》2012,26(2):176-188

Based on the ERA-40 and NCEP/NCAR reanalysis data,the NOAA Climate Prediction Center’s merged analysis of precipitation(CMAP),and the fifth-generation PSU/NCAR Mesoscale Model version 3(MM5v3),we defined a monsoon intensity index over the East Asian tropical region and analyzed the impacts of summer(June-July) South China Sea(SCS) monsoon anomaly on monsoon precipitation over the middle-lower reaches of the Yangtze River(MLRYR) using both observational data analysis and numerical simulation methods.The results from the data analysis show that the interannual variations of the tropical monsoon over the SCS are negatively correlated with the southwesterly winds and precipitation over the MLRYR during June-July.Corresponding to stronger(weaker) tropical monsoon and precipitation,the southwesterly winds are weaker(stronger) over the MLRYR,with less(more) local precipitation.The simulation results further exhibit that when changing the SCS monsoon intensity,there are significant variations of monsoon and precipitation over the MLRYR.The simulated anomalies generally consist with the observations,which verifies the impact of the tropical monsoon on the monsoon precipitation over the MLRYR.This impact might be supported by certain physical processes.Moreover,when the tropical summer monsoon is stronger,the tropical anomalous westerly winds and positive precipitation anomalies usually maintain in the tropics and do not move northward into the MLRYR,hence the transport of water vapor toward southern China is weakened and the southwest flow and precipitation over southern China are also attenuated.On the other hand,the strengthened tropical monsoon may result in the weakening and southward shift of the western Pacific subtropical high through self-adjustment of the atmospheric circulation,leading to the weakening of the monsoon flows and precipitation over the MLRYR.  相似文献   

A Simulation Study on the Extreme Temperature Events of the 20th Century by Using the BCC_AGCM   总被引：3，自引：1，他引：2       下载免费PDF全文

DONG Min  WU Tongwen  WANG Zaizhi  CHENG Yanjie  ZHANG Fang 《Acta Meteorologica Sinica》2012,26(4):489-506

Extreme temperature events are simulated by using the Beijing Climate Center Atmospheric General Circulation Model (BCC AGCM) in this paper. The model has been run for 136 yr with the observed external forcing data including solar insolation, greenhouse gases, and monthly sea surface temperature (SST). The daily maximum and minimum temperatures are simulated by the model, and 16 indices representing various extreme temperature events are calculated based on these two variables. The results show that the maximum of daily maximum temperature (TXX), maximum of daily minimum (TNX), minimum of daily maximum (TXN), minimum of daily minimum (TNN), warm days (TX90p), warm nights (TN90p), summer days (SU25), tropical nights (TR20), and warm spell duration index (WSDI) have increasing trends during the 20th century in most regions of the world, while the cold days (TX10p), cold nights (TN10p), and cold spell duration index (CSDI) have decreasing trends. The probability density function (PDF) of warm/cold days/nights for three periods of 1881-1950, 1951- 1978, and 1979-2003 is examined. It is found that before 1950, the cold day/night has the largest probability, while for the period of 1979-2003, it has the smallest probability. In contrast to the decreasing trend of cold days/nights, the PDF of warm days/nights exhibits an opposite trend. In addition, the frost days (FD) and ice days (ID) have decreasing trends, the growing season has lengthened, and the diurnal temperature range is getting smaller during the 20th century. A comparison of the above extreme temperature indices between the model output and NCEP data (taken as observation) for 1948-2000 indicates that the mean values and the trends of the simulated indices are close to the observations, and overall there is a high correlation between the simulated indices and the observations. But the simulated trends of FD, ID, growing season length, and diurnal temperature range are not consistent with the observations and their correlations are low or even negative. This indicates that the model is incapable to simulate these four indices although it has captured most indices of the extreme temperature events.  相似文献