Verification of the motion fields over Southeast Asia by the Florida State University (FSU) superensemble forecast     

Mastura Mahmud  Robert S. Ross 《Singapore journal of tropical geography》2006,27(2):176-190

The Florida State University (FSU) multimodel superensemble forecast is evaluated against several other operational weather models for the Southeast Asia region. The superensemble technique has demonstrated its exceptional skills in forecasting precipitation, motion and mass fields compared to either individual global operational or ensemble mean forecasts. The motion field investigation for the season of 2001 reveals that the superensemble forecasts are closer to the observed data compared to the other global member operational models through its low systematic errors at the 850 hPa level. The FSU multimodel superensemble forecasts exhibit the lowest root mean square errors (RSMEs), the highest correlation against the best observed data and the lowest systematic errors compared to the other operational model members. These forecasts have the potential to provide better daily weather predictions over the Southeast Asia region, particularly during the early northeast monsoon that often causes heavy rainfall in the equatorial part of the Southeast Asia region.  相似文献   

热带地区100 hPa东风气流的气候效应(Ⅱ): 与华北夏季降水的关系     

徐忠峰  钱永甫 《高原气象》2005,24(4):570-576

利用1954-1998年NCAR／NCEP再分析资料及同期我国160个测站月降水资料，分析了热带地区100hPa东风与华北夏季降水之间的关系。结果表明：（1）从春季到夏季，东风强度与华北夏季降水具有显著而稳定的正相关关系。（2）弱东风年夏季，印度洋及印度次大陆表面温度均为正异常，然而赤道印度洋地区的正异常明显强于其南北两侧。海温异常的这一分布特征，一方面使得100hPa东风减弱；另一方面使得南亚地区海陆热力对比减弱，导致南亚夏季风偏弱，进而造成由该季风区向华北地区的水汽输送减少，华北地区干旱。  相似文献   

湿位涡守恒条件下西南涡的发展   总被引：9，自引：0，他引：9  

朱禾  邓北胜  吴洪 《气象学报》2002,60(3):343-351

运用高分辨率数值预报模式 (HIRLAM)模拟了一次中国西南地区在多种活跃天气系统影响下 ,西南涡的发展过程。分析了东亚季风、青藏高压、地形等多种尺度与不同高低空环流形势配合以及在湿位涡守恒条件下对流发展时 ,潜热及不稳定能量的释放 ,对中尺度涡旋和强对流发生发展的作用 ,探讨了西南涡和局地降水增强与消亡的成因与理论 ,并具有实用意义  相似文献   

用一个耦合的全球格点大气环流模式-植被模式模拟中全新世气候变化   总被引：19，自引：7，他引：19  

Wang Huijun 《大气科学进展》2002,19(2):205-218

用一个耦合的全球格点大气环流模式－植被模式模拟中全新世的气候变化，模拟试验中考虑了地球轨道参数的变化，而其他强迫条件均取成现今值。结果表明，耦合的模式能够模拟出较今强的大尺度夏季风，特别是亚洲－非洲季风，而其他季节和区域的变化值一般都比较小。季风环流和季风降水都大幅度地增大了。结果还显示，耦合模式模拟的大尺度季风系统的变化同单纯大气环流模式模拟的结果非常相似，但是，在非洲北部季风区耦合模式模拟的降水和温度变化较单纯大气模式模拟的值要大，而且，耦合模式模拟的冬季降温值要比单纯大气模式模拟的结果小。  相似文献   

Impact of Southern Oscillation on the Frequency of Monsoon Depressions in the Bay of Bengal     

Singh  O. P.  Ali Khan  Tariq Masood  Rahman  Md. Sazedur 《Natural Hazards》2002,25(2):101-115

The impact of Southern Oscillation on thecyclogenesis over the Bay of Bengal duringthe summer monsoon has been investigated.The analysis of correlation coefficients(CCs) between the frequency of monsoondepressions and the Southern OscillationIndex (SOI) reveals that more depressionsform during July and August of El Niñoyears. Due to this, the seasonal frequencyof monsoon depressions remains little higherduring El Niño epochs even though thecorrelations for June and September are notsignificant. The CCs for July and August aresignificant at the 99% level.The El Niño-Southern Oscillation (ENSO)is known to affect Indian MonsoonRainfall (IMR) adversely. The enhancedcyclogenesis over the Bay of Bengal duringJuly and August is an impact of ENSO whichneeds to be examined closely. Increasedcyclogenesis over the Bay of Bengal may bereducing the deficiency in IMR duringEl Niño years by producing more rainfallover the eastern parts of India duringJuly and August. Thus there is a considerablespatial variation in the impact of ENSOon the monsoon rainfall over India and El Niñoneed not necessarily imply a monsoonfailure everywhere in India.The area of formation of monsoon depressionsshifts eastward during El Niño years.Warmer sea surface temperature (SST) anomaliesprevail over northwest and adjoiningwestcentral Bay of Bengal during premonsoon andmonsoon seasons of El Niño years.May minus March SOI can provide useful predictionsof monsoon depression frequencyduring July and August.  相似文献   

Reconstruction of the climate in the Tianmu Mountain area, Zhejiang Province, in the last 160 years by ? 13C sequence of tree ring α-cellulose     

钱君龙  吕军  屠其璞  王苏民 《中国科学D辑(英文版)》2002,45(5)

Based on cross-dating tree rings from the Tianmu Mountain, Zhejiang Province, the tree rings α-cellulose δ 13C time series was measured. By spectrum analysis, the variation of tree-ring δ13C sequence shows a quasi periodicity of 4.4 years, which is coincident with the standard cycle of El Nino. After removing the long-term decrease trend of the δ13C variation related to atmospheric CO2 concentration, the response of the δ13C to climate elements was analyzed using meteorology data from a nearby weather station. The results suggest that there is a distinct relativity between high-frequency variation of tree ring δ 13C series and seasonal climate parameters, e.g. Temperature and precipitation, with a significant time-lag effect. In addition, the high frequency also reflects the strength change of the East Asian Monsoon. The multiple regression method was employed to reconstruct the historical climate, and to analyze the climate change and trend in the last 160 years in the northern Zhejiang Province.  相似文献   

多种驱动力作用下东亚大陆形变及应力场演化   总被引：7，自引：0，他引：7  

李祖宁  傅容珊  郑勇  董树谦 《地震学报》2002,24(1):17-26

将印度板块持续地向北推进、下伏地幔小尺度对流对增厚大陆岩石层的搬离作用以及剥蚀作用视为形成现今东亚大陆形变和应力场格局的主驱动力。在一梯形区域内，利用数值模拟的方法，研究了东亚大陆在不同的边界条件、不同的剥蚀率系数及不同的岩石力学参数条件下的形变及应力场格局。与现代空间大地测量技术 CGPS)以及利用地震观测得到的结果进行了对比。结果表明，本文模型预测的结果与上述的观测结果有较好的吻合，其西部地区比东部吻合得更好。说明控制东亚大陆西部形变和应力场基本格局的主驱动力，来源于印度板块对欧亚板块的碰撞、挤压，而对东部地区还应当考虑其与太平洋板块和菲律宾板块的相互作用。与此同时，下伏地幔小尺度对流对增厚大陆岩石层的搬离作用以及风化剥蚀对应力场的演化过程也不可忽视。   相似文献   

The geography of water conflict and cooperation: internal pressures and international manifestations   总被引：2，自引：0，他引：2  

Meredith Giordano  Mark Giordano  & Aaron Wolf 《The Geographical journal》2002,168(4):293-312

Studies on transboundary water conflict and cooperation generally consider interstate relations over shared water resources as distinct from intrastate relations. While connections have been made between international water relations and regional relationships in general, it is conceivable that international water conflict and cooperation may also be influenced by domestic water events and vice versa. This paper seeks to investigate the dynamics of water interactions across geographic scale and their relationship to broader international affairs. The research approach involves the creation of an analytical framework for assessing possible linkages between external and internal interactions over freshwater resources. The framework is applied to three case studies – the Middle East, South Asia and Southern Africa – utilizing 'event data'. To validate the findings from the quantitative analyses, the results are compared with conventional qualitative understandings of water and overall relations in the three regions. The comparison demonstrates not only the efficacy of the analytical framework in general, but also highlights, at least in terms of the specific case studies selected, the disparate water dynamics across geographic regions and the importance of considering water events, both national and international, within larger political and historical contexts.  相似文献   

The S-velocity structure of the East Asian mantle from inversion of shear and surface waveforms   总被引：15，自引：0，他引：15  

Wolfgang Friederich 《Geophysical Journal International》2003,153(1):88-102

  相似文献   

东亚地区现代地壳运动特征与构造变形   总被引：4，自引：1，他引：4  

任金卫  马宗晋 《地学前缘》2003,10(Z1):58-65

根据“中国地壳运动观测网络”首次发布的GPS观测结果以及国际地球自转服务中心在 2 0 0 0年发布的ITRF97下的站速度矢量和“东南亚地球动力学项目”GPS网的观测结果 ,讨论了东亚地区现今地壳运动和构造变形特征。在ITRF97参考系下 ,中国大陆东部现今地壳运动以向南东方向(12 0 130°)运动为主 ,量值平均为 35mm/a ,西部受印度板块向北东碰撞的影响 ,运动方向发生偏转 ,呈显北东—近东西向运动 ,但这种影响涉及的范围达到了准噶尔盆地北缘一线 ,说明碰撞型板块边界对板内变形的影响远大于俯冲型板块边界。平均来看 ,75 %以上的印度板块相对于欧亚板块间的南北向缩短是通过地壳增厚变形来吸收的 ,这意味着在调节整个青藏高原构造变形的过程中 ,逆断和地壳增厚起了主要的作用。东南亚块体总体上与欧亚板块的运动有所差异 ,相对于欧亚大陆有 10mm/a左右向东的运动。菲律宾板块南部向西的运动速度只有 2 4mm/a。包括华南地块在内的东南亚块体的运动不仅仅是与印度板块的碰撞过程有关 ,也应当与沿着东南亚块体东边界的俯冲过程有关。  相似文献