区域海气耦合模式FROALS的发展及其应用     

周天军  邹立维  韩振宇  刘博  姚隽琛 《大气科学》2016,40(1):86-101

区域海气耦合模式是研究局地海气相互作用过程影响气候变率的重要平台,也是对全球气候模式进行"动力降尺度"的重要工具.本文介绍了LASG(State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics)/IAP(Institute of Atmospheric Physics)发展的区域海气耦合模式FROALS(Flexible Regional Ocean-Atmosphere-Land System model),并总结了过去五年围绕该区域海气耦合模式开展的研究工 作.FROALS的特点之一是有两个完全不同的大气模式分量和海洋模式分量选项,可以适应不同的模拟研究需 求.针对区域海气耦合模式在西北太平洋地区的模拟偏差,通过分步骤考察不同大气模式分量和不同海洋模式分量对模式模拟性能的影响,指出大气模式是导致区域海气耦合偏差的主要分量.通过改进对流触发的相对湿度阈值标准,有效地改善了此前区域海气耦合模式在亚洲季风区普遍出现的"模拟海温冷偏差".改进的FROALS对西北太平洋地区的大气和海洋环境有较好的模拟能力,合理地再现了西北太平洋地区表层洋流气候态和年际变率.较之非耦合模式,考虑区域海气耦合过程后,改进了东亚和南亚地区的降水和热带气旋潜势年际变率的模拟.最后,针对东亚—西北太平洋地区,利用FROALS对IAP/LASG全球气候模式模拟和预估的结果进行了动力降尺 度,得到了东亚区域50 km高分辨率区域气候变化信息.分析显示,FROALS模拟得到的东亚区域气候较之全球气候模式和非耦合区域气候模式结果具有明显的"增值",显示出区域海气耦合模式在该区域良好的应用前景.  相似文献   

南海夏季风爆发早晚的经向环流异常的机理研究   总被引：1，自引：0，他引：1  

温之平  吴乃庚  陈桂兴 《大气科学》2016,40(1):63-77

南海夏季风爆发与东亚地区的局地经向环流密切相关.本文利用线性局地经向环流诊断模式,定量诊断分析了1979~2003年5月1~15日的局地经向环流及其在夏季风爆发早晚年的差异,分析找出了在该关键时段对经向环流异常有正贡献的主要因子,从而确立影响季风爆发的相应天气过程及贡献机制.结果表明,在季风爆发早年期间,局地经向环流异常呈现为"Hadley环流"形态:上升运动(下沉运动)影响南海中北部(江淮地区),低空非地转南风(北风)影响南海中南部(华南和江南地区).季风爆发晚年的情况则与季风爆发早年相反.对造成经向环流异常的各个因子进行定量分析发现,经向分布不均匀的潜热加热的贡献作用最大,其次是温度平流和西风动量输送过程,与越赤道气流有关的边界效应则对南海中南部的低空南风有一定贡献.相应的天气学分析表明,季风爆发偏早年的副热带高空急流强度偏强且位置偏南,其动量输送过程导致对流层上层出现非地转南风、急流轴南侧(北侧)的华南(华北)地区出现高空辐散(辐合)和低层辐合上升(辐散下沉).与此同时,中纬度西风带扰动的南下和副热带高压脊从南海地区的撤出,中低层温度平流导致华中地区冷却和南海中北部增暖,进一步加强低纬地区上升、中纬地区下沉的经向环流异常.华南地区异常的非地转北风与南海中南部异常的非地转南风,显著加强了南海中北部的低空水汽辐合和对流潜热释放,从而激发出强烈上升运动.由此可见,中低纬天气系统配置能有效调节中国东部及南海地区的潜热加热和冷暖平流的南北分布,从而引起与季风爆发对应的局地经向环流的显著变化.  相似文献   

热带气旋生成过程的中尺度涡旋活动数值模拟   总被引：1，自引：1，他引：0  

姜舒婕  吴立广  梁佳 《气象科学》2016,36(6):779-788

热带气旋生成过程中包含不同尺度环流及其相互作用。为此,本文将热带气旋生成数值模拟的起点提前到模拟中尺度涡旋(MCV)的生成,从而利用高分辨率数值试验结果,对热带气旋过程中的不同尺度涡旋活动进行分析。模式首先模拟了季风涡旋的东南侧增强的西南气流中出现低形变旋转性扰动,随着扰动的旋转性增强,中层出现水平尺度为200 km左右的MCV。在扰动区内的不同高度上还发现10~20 km尺度不等的中γ气旋性涡旋扰动,其中部分涡旋扰动具有热塔的特征,中γ气旋性涡旋扰动在MCV的旋转环境内不断组织化,低层气旋性涡旋扰动的分布比中层更加集中。模拟表明这些较小尺度的气旋性中尺度涡旋扰动对热带气旋的生成有重要作用。  相似文献   

冲绳海槽中部17 000 a以来沉积物中微量元素的组成特征及其对古环境的指示     

彭娜娜  曾志刚 《海洋科学》2016,40(4):126-139

基于加速器质谱仪AMS14C高精度定年,以及应用电感耦合等离子体质谱仪(ICP-MS)对S10孔岩芯沉积物进行微量元素测试,对冲绳海槽中部沉积物的微量元素组成及其记录的物源和古环境信息展开研究。研究结果显示,稀土元素、Th、Nb和Ta元素反映陆源碎屑混合矿物的化学组成特征,Zr和Hf元素指示锆石矿物的化学组成,锆石主要为火山来源,Sc元素可能与铁镁物质有关。稀土元素分析表明沉积物主要由陆源和火山源物质组成,陆源物质主要来自长江和黄河,不同时期,各源区物质贡献量不同:16 500~11 600 a,长江、黄河为沉积物的主要物质来源;11 600~7 750 a,长江物质贡献减少,黄河物质为主;7 750~6 450 a,K-Ah火山物质为主,长江、黄河物质供给骤减;6 450~3 900 a,长江、黄河陆源物质输入增加,4 000 a左右受火山作用影响;3 900~1 900 a,长江、黄河陆源物质输入持续增多;1 900 a以来长江、黄河物质仍有增加,且以黄河物质为主。此外,物源判别公式研究显示台湾物质输入量不能有效反映黑潮演变,而长江、黄河物质输入量对17 000 a以来东亚冬季风的强弱变化有很好的指示,可作为东亚冬季风演变的新证据。这些研究结果表明,冲绳海槽中部微量元素研究可得到海槽17 000 a以来物源及东亚冬季风的演化情况,有助于重建全新世以来沉积物物源及古环境的演变历史。  相似文献   

Coccolith assemblages and their response to climate and surface hydrography in the Yellow Sea,Northwest Pacific,AD 1780–2011     

苑明莉  黄建生  孙军  孙耀 《海洋学报(英文版)》2016,35(10):56-62

A study of coccolith assemblages from a box core from the central South Yellow Sea(SYS) was performed revealing fluctuations on their relative abundance(%) that can be related to climatic and hydrographic changes over the last 230 years(1780–2011). Total coccolith abundances ranged from 7.0 to 55.1×10~6 coccoliths·g~(-1)sediment. Although the abundance of different species varied widely throughout the core, seven taxa dominated the assemblage. Among these species, Gephyrocapsa oceanica was the most dominant species, and it showed an average percentage of 50.1%. The pattern of G. oceanica(eutrophic species) was opposite to that of the combined percentage of Braarudosphaera bigelowii and Umbilicosphaera sibogae(both oligotrophic species), indicating that in the Yellow Sea(YS), the distribution pattern of G. oceanica might be characteristic of nutrient availability.Similar patterns between G. oceanica and the Siberian High were observed on an inter-decadal time scale,indicating that the East Asian Winter Monsoon(EAWM) may be an important driver of ecological changes in the YS. When the EAWM prevails, both the Yellow Sea Coastal Current(YSCC) and Yellow Sea Warm Current(YSWC)strengthen, and the increasing nutrient availability and warmer water brought by the strengthened YSWC favor eutrophic and warm-water coccolithophore species, such as G. oceanica. This likely mechanism demonstrates that coccolith assemblages can be used as benign and reliable proxy for climate change and surface oceanography.  相似文献   

Annual cycle of the upper-ocean circulation and properties in the tropical western Indian Ocean     

M Manyilizu  P Penven  CJC Reason 《African Journal of Marine Science》2016,38(1):81-99

A regional ocean model was used to simulate the annual cycle of the upper-ocean dynamics and its influence on ocean properties in the tropical western Indian Ocean. Surface winds and heat fluxes from the National Centers for Environmental Prediction (NCEP) reanalysis forced the model (Model_NCEP) with initial and lateral boundary conditions derived from the Simple Ocean Data Assimilation (SODA). The model findings were in good agreement with previous research, satellite and observational data as well as another model configuration forced by Comprehensive Ocean and Atmosphere Data Sets (COADS). The initial and lateral boundary conditions for Model_COADS were extracted from World Ocean Atlas 2001. Anticyclonic wind stress curl occurred to the north of Madagascar, and extended towards the Tanzanian coast throughout the year, leading to Ekman convergence and downwelling in that region. The lowest sea-surface height values during the year occurred between 5° and 12° S with an elongated and contracted shape. The East African Coastal Current (EACC) was in phase with the westward North-East Madagascar Current (NEMC) throughout the year with volume transports peaking in June through July in the model forced by NCEP reanalysis. The variability of the volume transport, ocean currents, temperature and salinity to the north of Madagascar on the path of the NEMC mirrored those in the middle Tanzanian shelf on the path of the EACC throughout the year. The NEMC seemed to influence the water masses on the Tanzanian shelf, with cooler and lower-salinity water in the South-West Monsoon, and warmer and saltier water during the North-East Monsoon.  相似文献   

Effect of basic state on seasonal variation of convectively coupled Rossby wave     

《Dynamics of Atmospheres and Oceans》2017

Convectively coupled equatorial Rossby (ER) waves display maximum varability over the northern hemisphere during boreal summer and over the southern hemisphere during boreal winter. It suggests that the seasonal variation of ER waves is significantly affected by the annual cycle of basic state. However, which specific environmental factor plays a determining role remains obscure. This study investigates the background influence on the seasonal variation of ER wave by employing an intermediate anomaly atmospheric model. By prescribing boreal summer/winter seasonal mean state as the model’s basic state, the authors found that the model is able to simulate the trapping of the ER wave purtrubation over the northern/southern hemisphere as in observation. Further sensitivity experiments suggest that the moisture distribution plays a major role in modulating the ER wave structure while the mosoonal flows play a minor role.  相似文献   

九州台古土壤S1记录的末次间冰期东亚夏季风变化   总被引：1，自引：0，他引：1  

饶志国  陈发虎  汪海斌  张家武  朱照宇 《海洋地质与第四纪地质》2006,26(2):103-111

对沉积速率较高的黄土高原西部地区九州台剖面S1古土壤的夏季风代用指标———磁化率、碳酸钙含量、色度进行了测量。综合分析结果表明,MIS5e开始前,夏季风有一次衰退事件,末次盛间冰期早期夏季风强于晚期,而中期夏季风强度相对较弱,然而这种变化是较为和缓的,并没有表现出类似GRIP冰心氧同位素的大幅度、快速变化,表明MIS5e期间东亚夏季风是相对稳定的。来自海洋的研究表明,西太平洋洋面温度(SST)和洋面高度在MIS5e早期和晚期相对较高,中期相对较低,证实了西太平洋环境变化和东亚夏季风强度之间存在成因上的联系。与先前有关全新世东亚夏季风研究结果的对比表明,MIS5e和全新世东亚夏季风演化具有一定的相似性,可能反映了低纬海洋和高纬大陆之间能量和物质交换对太阳辐射响应的某种内在机制。  相似文献   

夏季珠江冲淡水扩散路径分析   总被引：9，自引：0，他引：9  

庞海龙  高会旺  宋萍萍  游大伟  陈举 《海洋预报》2006,23(3):58-63

利用1978~1988年国家海洋局南海分局南海北部断面调查获得的盐度资料,分析了珠江口附近海域盐度的时空分布特征,描述了夏季珠江冲淡水的扩散路径。通过统计分析相应时间段的风场、平均海平面高度、珠江径流以及陆地降水等资料,讨论了影响珠江冲淡水扩散的主要因子。我们发现:夏季珠江冲淡水扩散方向与南风强度(频率和平均风速)、近岸海面月平均高度以及径流强度的关系极为密切,如果西南季风强盛,珠江冲淡水向东扩散就多;如果近岸海面高度显著增高,珠江冲淡水向西流动就特别强。  相似文献   

Study on circulation and meso-scale eddies in the South China Sea in summer of 1998     

Xu Jianping  Xue Huijie  Shi Maochong  Liu Zenghong 《海洋学报(英文版)》2002,21(4):469-481

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