STUDY ON THE CHARACTERISTICS OF TROPICAL CYCLONES ACTIVITY OVER THE WESTERN NORTH PACIFIC IN 2004 AND THE CAUSATION     

董美莹  郑沛群  薛根元 《热带气象学报(英文版)》2007,13(1):49-52

In this paper, we summarized the characteristics of tropical cyclones (TC) activity over the western North Pacific in 2004 and analyzed their causation. Compared with the normal, the annual frequency of TC in 2004 was slightly higher, tropical cyclones in 2004 had a longer life span and occurred in a concentrated period, the source of TC were situated eastward; in all tracks of TC, the recurvature tracks took up larger proportion, the landfall regions of TC were located northward, which concentrated from East China to Japan. The primary causes were revealed as follows. Firstly, the intensity and area of the western North Pacific subtropical high was stronger and larger than usual respectively, and its ridge was frequently in the form of cells and stretched northwestward. Secondly, the convergence of intertropical convergence zone (ITCZ) was reinforced and the convergence zone moved more eastward than average. Thirdly, the meridionality of the westerlies was larger than average and the cell-shaped ridge formed a saddle region, which is in favor of TC northward motion and recurature.  相似文献   

DIAGNOSTIC INVESTIGATION OF SIMULATION BIAS WITH THE GRAPES-MESO MODEL FOR A TORRENTIAL RAIN CASE     

孔荣  王建捷 《热带气象学报(英文版)》2007,13(1):69-72

In this paper, the numerical simulation bias of the non-hydrostatic version GRAPES-Meso (Mesoscale of the Global and Regional Assimilation and Prediction System) at the resolution of 0.18o for a torrential rain case, which happened in May 31st to June 1st 2005 over Hunan province, are diagnosed and investigated by using the radiosondes, intensive surface observation, and the operational global analysis data, and the sensitivity experimental results as well. It is shown in the result that the GRAPES-Meso could reproduce quite well the main features of large-cale circulation and the distribution of the accumulated 24h precipitation and the key locations of the torrential rainfall are captured reasonably well by the model. However, bias exist in the simulation of the mesoscale features of the torrential rain and details of the relevant systems, for example, the simulated rainfall that is too earlier in model integration and remarkable underprediction of the peak value of rainfall rates over the heaviest rainfall region, the weakness of the upper jet simulation and the overprediction of the south-west wind in the lower troposphere etc. The investigation reveals that the sources of the simulation bias are different. The erroneous model rainfall in the earlier integration stage over the heaviest rainfall region is induced by the model initial condition bias of the wind field at about 925hPa over the torrential rainfall region, where the bias grow rapidly and spread upward to about 600hPa level within the few hours into the integration and result in abnormal convergence of the wind and moisture, and thus the unreal rainfall over that region. The large bias on the simulated rainfall intensity over the heaviest rainfall region might be imputed to the following combined factors of (1) the simulation bias on the strength and detailed structures of the upper-level jet core which bring about significant underpredictions of the dynamic conditions (including upper-level divergence and the upward motion) for heavy rainfall due to unfavorable mesoscale vertical coupling between the strong upper-level divergence and lower-level convergence; and (2) the inefficient coupling of the cumulous parameterization scheme and the explicit moisture in the integration, which causes the failure of the explicit moisture scheme in generating grid-scale rainfall in a certain extent through inadequate convective adjustment and feedback to the grid-scale. In addition, the interaction of the combined two factors could form a negative feedback to the rainfall intensity simulation, and eventually lead to the obvious underprediction of the rainfall rate.  相似文献   

NUMERICAL EXPERIMENTS OF EFFECT OF SSTA OVER THE INDIAN OCEAN ON ATMOSPHERIC LOW-FREQUENCY OSCILLATION IN THE EXTRATROPICAL LATITUDE     

邱明宇  陆维松  陈汇林  蔡亲波 《热带气象学报(英文版)》2007,13(1):73-76

Numerical experiments on forcing dissipation and heating response of dipole (unipole) are carried out using global spectral models with quasi-geostrophic barotropic vorticity equations. For each experiment model integration is run for 90 days on the condition of three-wave quasi-resonance. The results are given as follows: Under the effects of dipole (unipole) forcing source and basic flow intensity, there exist strong interactions among the three planetary waves and quasi-biweekly and intraseasonal oscillation of the three planetary waves. In the meantime, the changes in the intensity of dipole or unipole forcing source and basic flow have different frequency modulation effects on LFO in the middle and higher latitudes. The results of the stream function field of three quasi-resonant waves evolving with time confirm that the low-frequency oscillation exists in extratropical latitude.  相似文献   

THE RELATIONSHIP BETWEEN SCS SUMMER MONSOON INTENSITY AND OCEANIC THERMODYNAMIC VARIABLES AT DIFFERENT TIME SCALE     

谷德军  纪忠萍  王东晓  梁建茵  方一川 《热带气象学报(英文版)》2007,13(1):85-88

The oscillation characteristics of 1948 - 2003 South China Sea (SCS) summer monsoon intensity (SCSSMI) is analyzed by wavelet transform and the relationship between SCSSMI filtered by Lanczos filter at different time scale and oceanic thermal conditions is studied. The results show that SCSSMI exhibits dominant interannual (about 4 a), decadal (about 9 a) and interdecadal (about 38 a) oscillation periods. The interannual variation is the strongest and the interdecadal variation the weakest. The region of significant correlation between SCS summer monsoon intensity and oceanic thermodynamic variables at different time scale is greatly different. Significant correlation area of interannual variation of SCSSMI is concentrated in near equatorial region. Corresponding correlation displays quasi-biannual variability. If positive anomalies of SST and the depth of thermocline happen in eastern equatorial Indian Ocean and western equatorial Pacific, and negative anomalies of SST and the depth of thermocline happen in western equatorial Indian Ocean and eastern equatorial Pacific in previous autumn and winter, the interannual variation of SCSSMI will enhance. If the condition is contrary, interannual variation of SCSSMI will weaken. The interannual variation of SCSSMI will influence SST. The region surrounding SCS and east of Australia shows significantly negative correlation in autumn, and significantly positive correlation exhibits in west equatorial Indian Ocean, eastern equatorial Pacific and equatorial Atlantic in winter. The decadal variation of SCSSMI is modulated by PDO. Interdecadal variation of SCSSMI is relevant to the global warming and PDO.  相似文献   

第二届亚洲气候与冰冻圈国际学术大会在兰州召开          下载免费PDF全文

谢爱红 《气候变化研究进展》2007,3(6):367-367

2007年10月22-26日,第二届亚洲气候与冰冻圈国际学术大会在兰州召开。会议由世界气候研究计划/气候与冰冻圈计划（WCRP/CliC）、中国CliC国家委员会、日本CliC国家委员会和甘肃省气象局联合主办。来自中国、日本、俄罗斯、蒙古、乌兹别克斯坦、塔吉克斯坦、印度，巴基斯坦、尼泊尔、韩国、美国、加拿大、英国，挪成等国家的148位代表出席了大会。  相似文献   

施秉县牛大场太子参种植栽培的气候条件分析   总被引：1，自引：0，他引：1  

田楠  王洪斌  梁平  韦波 《贵州气象》2007,31(6):14-16

利用施秉县牛大场中药材种植基地2004-08—2006-12两要素气象自动观测站所观测的气温和降雨资料,根据太子参种植生产所需的关键气象因素以及近10 a来的生产实践经验,详细分析研究了施秉牛大场太子参生产种植基地太子参生产的气候条件的优劣,得出了基地的光温水条件适宜于太子参的种植生产,自然的阴湿条件,有效地降低了太子参种植生产的产出投入比的结论。  相似文献   

Recent Progress in the Impact of the Tibetan Plateau on Climate in China   总被引：14，自引：0，他引：14  

刘屹岷  包庆  段安民  钱正安  吴国雄 《大气科学进展》2007,24(6):1060-1076

Studies of the impacts of the Tibetan Plateau （TP） on climate in China in the last four years are reviewed. It is reported that temperature and precipitation over the TP have increased during recent decades. From satellite data analysis, it is demonstrated that most of the precipitation over the TP is from deep convection clouds. Moreover, the huge TP mechanical forcing and extraordinary elevated thermal forcing impose remarkable impacts upon local circulation and global climate. In winter and spring, stream flow is deflected by a large obstacle and appears as an asymmetric dipole, making East Asia much colder than mid Asia in winter and forming persistent rainfall in late winter and early spring over South China. In late spring, TP heating contributes to the establishment and intensification of the South Asian high and the abrupt seasonal transition of the surrounding circulations. In summer, TP heating in conjunction with the TP air pump cause the deviating stream field to resemble a cyclonic spiral, converging towards and rising over the TP. Therefore, the prominent Asian monsoon climate over East Asia and the dry climate over mid Asia in summer are forced by both TP local forcing and Eurasian continental forcing.
Due to the longer memory of snow and soil moisture, the TP thermal status both in summer and in late winter and spring can influence the variation of Eastern Asian summer rainfall. A combined index using both snow cover over the TP and the ENSO index in winter shows a better seasonal forecast.
On the other hand, strong sensible heating over the Tibetan Plateau in spring contributes significantly to anchor the earliest Asian monsoon being over the eastern Bay of Bengal （BOB） and the western Indochina peninsula. Qualitative prediction of the BOB monsoon onset was attempted by using the sign of meridional temperature gradient in March in the upper troposphere, or at 400 hPa over the TP. It is also demonstrated by a numerical experiment and theoretical study that the heating over the TP lea  相似文献   

2007年夏季(6-8月)内蒙古地区气候影响评价     

杨丽桃 《内蒙古气象》2007,(5):15-15

1气候概况1.1气温夏季全区平均气温在16.4℃(图里河)~27.0℃(拐子湖)之间,与常年同期平均值相比,全区大部地区偏高到异常偏高,距平在1~4℃之间,其中呼伦贝尔市西部、锡林郭勒盟东北部距平最大为3~4℃。1.2降水夏季全区降水量在20mm(额济纳)~383mm(青龙山)之间,降水主要集中在鄂  相似文献   

对提高公共气象服务水平的认识     

杨春燕 《内蒙古气象》2007,(5):50-50

随着气象事业的快速发展,现代化的气象信息监测系统和天气预报预测分析系统逐步建成,气候观测基础工作正在加强,气象科技创新能力不断加快,气象服务领域进一步拓展,公共气象服务对于包头市经济建设发挥着越来越重要的作用。充分认识公共气象服务的重要性、切实提高气象服务能力  相似文献   

吉林省2006年冬季的天气气候特点及影响     

程红军 《吉林气象》2007,(3):9-10

2006年冬季(2006年11月1日～2007年2月28日)吉林省总的天气气候特点是:气温特高,降水接近常年。冷空气活动少且强度弱,气温持续偏高;降水时间分布呈前冬(2006年11～12月)少,后冬(2007年1～2月)偏多,空间分布呈东南部山区(吉林、通化、白山)略多,其它市(州)略少的特点。本文简要分析了冬季的天气特点、环流特征及对人民生产生活的影响。  相似文献