Simulation of Volume and Heat Transport along 26.5°N in the Atlantic          下载免费PDF全文

MO Hui-Er  YU Yong-Qiang 《大气和海洋科学快报》2012,5(5):373-378

The observed meridional overturning circulation (MOC) and meridional heat transport (MHT) estimated from the Rapid Climate Change/Meridional Circulation and Heat Flux Array (RAPID/MOCHA) at 26.5°N are used to evaluate the volume and heat transport in the eddy-resolving model LASG/IAP Climate system Ocean Model (LICOM). The authors find that the Florida Current transport and upper mid-ocean transport of the model are underestimated against the observations. The simulated variability of MOC and MHT show a high correlation with the observations, exceeding 0.6. Both the simu-lated and observed MOC and MHT show a significant seasonal variability. According to the power spectrum analysis, LICOM can represent the mesoscale eddy characteristic of the MOC similar to the observation. The model shows a high correlation of 0.58 for the internal upper mid-ocean transport (MO) and a density difference between the western and eastern boundaries, as noted in previous studies.  相似文献   

印度洋赤道潜流年际变化特征及其与印度洋偶极子的联系     

李俊灵  徐康  王卫强  谢强 《海洋与湖沼》2022,53(1):19-32

印度洋赤道潜流(equatorial undercurrent,EUC)是赤道流系的重要组成部分,对印度洋物质输运和能量交换有着重要意义.基于SODA 3.4.2海洋再分析数据,对印度洋EUC的三维空间结构和年际变化特征进行分析,并揭示其年际变率与印度洋偶极子(Indian Ocean dipole,IOD)的联系.结...  相似文献   

Relationship between ENSO and Winter Rainfall over Southeast China and Its Decadal Variability   总被引：5，自引：0，他引：5  

LI Chun  MA Hao 《大气科学进展》2012,29(6):1129-1141

In this study,the relationship between El Nin o-Southern Oscillation(ENSO) and winter rainfall over Southeast China(SC) is demonstrated based on instrumental and reanalysis data.The results show that ENSO and SC winter rainfall(ENSO-SC rainfall) are highly correlated and intimately coupled through an anomalous high pressure over the northwestern Pacific.In mature phase,El Nin o(La Nin a) events can cause more(less) rainfall over SC in winter.Due to the persistence and spring barrier of ENSO,SC winter rainfall has potential predictability of about half a year ahead with ENSO as a predictor.Besides,the ENSO-SC rainfall relationship exhibits decadal variability,closer before the early 1970s(0.47) and after the early 1990s(0.76),but weaker(0.12) between these times.In different periods,atmospheric teleconnection patterns have large differences and the predictability of SC winter rainfall also changes dramatically.For the most recent 20 years,the ENSO-SC rainfall relationship is closest and the prediction of SC winter rainfall anomalies based on ENSO is most creditable.In addition,the causes and mechanisms of the decadal modulation of the relationship between ENSO and SC winter rainfall need to be further studied.  相似文献   

Modulation of El Nino-Southern Oscillation by Freshwater Flux and Salinity Variability in the Tropical Pacific     

ZHANG Rong-Hu  ZHENG Fei  PEI Yuhu  ZHENG Quanan  WANG Zhanggui 《大气科学进展》2012,29(4):647-660

The El Nin o-Southern Oscillation (ENSO) is modulated by many factors; most previous studies have emphasized the roles of wind stress and heat flux in the tropical Pacific. Freshwater flux (FWF) is another environmental forcing to the ocean; its effect and the related ocean salinity variability in the ENSO region have been of increased interest recently. Currently, accurate quantifications of the FWF roles in the climate remain challenging; the related observations and coupled ocean-atmosphere modeling involve large elements of uncertainty. In this study, we utilized satellite-based data to represent FWF-induced feedback in the tropical Pacific climate system; we then incorporated these data into a hybrid coupled ocean-atmosphere model (HCM) to quantify its effects on ENSO. A new mechanism was revealed by which interannual FWF forcing modulates ENSO in a significant way. As a direct forcing, FWF exerts a significant influence on the ocean through sea surface salinity (SSS) and buoyancy flux (Q B ) in the western-central tropical Pacific. The SSS perturbations directly induced by ENSO-related interannual FWF variability affect the stability and mixing in the upper ocean. At the same time, the ENSO-induced FWF has a compensating effect on heat flux, acting to reduce interannual Q B variability during ENSO cycles. These FWF-induced processes in the ocean tend to modulate the vertical mixing and entrainment in the upper ocean, enhancing cooling during La Nin a and enhancing warming during El Nin o, respectively. The interannual FWF forcing-induced positive feedback acts to enhance ENSO amplitude and lengthen its time scales in the tropical Pacific coupled climate system.  相似文献   

Decadal Features of Heavy Rainfall Events in Eastern China   总被引：1，自引：0，他引：1       下载免费PDF全文

CHEN Huopo  SUN Jianqi  FAN Ke 《Acta Meteorologica Sinica》2012,26(3):289-303

Based on daily precipitation data, the spatial-temporal features of heavy rainfall events (HREs) during 1960-2009 are investigated. The results indicate that the HREs experienced strong decadal variability in the past 50 years, and the decadal features varied across regions. More HRE days are observed in the 1960s, 1980s, and 1990s over Northeast China (NEC); in the 1960s, 1970s, and 1990s over North China (NC); in the early 1960s, 1980s, and 2000s over the Huaihe River basin (HR); in the 1970s-1990s over the mid-lower reaches of the Yangtze River valley (YR); and in the 1970s and 1990s over South China (SC). These decadal changes of HRE days in eastern China are closely associated with the decadal variations of water content and stratification stability of the local atmosphere. The intensity of HREs in each sub-region is also characterized by strong decadal variability. The HRE intensity and frequency co-vary on the long-term trend, and show consistent variability over NEC, NC, and YR, but inconsistent variability over SC and HR. Further analysis of the relationships between the annual rainfall and HRE frequency as well as intensity indicates that the HRE frequency is the major contributor to the total rainfall variability in eastern China, while the HRE intensity shows only relative weak contribution.  相似文献   

近60年中国不同区域降水的气候变化特征   总被引：15，自引：2，他引：13  

李聪  肖子牛  张晓玲 《气象》2012,38(4):419-424

利用1951-2009年中国503站日降水量资料,研究了我国各季各地区降水年代际变化的特征,并分析了其对我国干旱演变的影响。结果表明：近60年来我国各区域年平均降水量大多为减少趋势,其中华北、西南地区减少明显;各地区秋季降水偏少的趋势最为显著,可能是导致秋季干旱增多以及秋冬连季干旱频繁的主要原因。2000年以后北方夏季降水呈减少趋势,其中华北夏季降水明显减少,而冬季降水趋于增加,南方秋季降水减少明显,而春季降水增多。云南等西南地区秋冬春连旱偏多的原因之一可能与孟加拉湾季风结束偏早有关。  相似文献   

长江口12.5 m深水航道回淤年际变化及成因          下载免费PDF全文

刘杰  程海峰  韩露  王珍珍 《水科学进展》2019,30(1):65-75

长江口12.5 m深水航道回淤量大,影响因素复杂。利用2011-2017年长江口航道水下地形、水文测验和航道回淤等系列资料,研究了12.5 m深水航道回淤的年际变化过程和原因。结果表明:① 12.5 m深水航道回淤总体呈现稳中下降的变化特征。②南港-圆圆沙段因航道滩槽高差的缩小和上游底沙输沙量的减少,回淤呈逐年减少态势。③北槽段因南坝田挡沙堤加高工程的实施和台风影响偏弱,2016-2017年回淤较此前有所减少;径流影响北槽最大浑浊带的发育部位,进而影响北槽航道回淤的部位,2016-2017年长江口径流量偏大是北槽航道主要回淤部位较往年偏下的主要原因。④流域减沙对12.5 m深水航道回淤的影响已开始显现。未来受其影响,南港-圆圆沙航道回淤有望进一步下降并维持较低量值,北槽航道回淤有望维持稳中下降态势。  相似文献   

玉龙雪山浅冰芯pH值对冰川作用区降水量变化的响应   总被引：7，自引：0，他引：7  

顾娟  何元庆  张忠林  卢爱刚  庞洪喜 《冰川冻土》2005,27(4):509-514

玉龙雪山10.10 m浅冰芯的pH和电导率(EC)变化分析以及与Ca2 、 Mg2 、 K 和Na 浓度的对比表明, 玉龙雪山主要受局地碱性陆源物质的控制.与丽江气象台站的降雨量资料比较发现, 在海洋性冰川区浅冰芯pH和电导率的变化与降雨量和周围地表可溶性离子的输入量关系密切, 并与降雨量呈显著的负相关关系.结合玉龙雪山主要由局地来源补给的特征, 引入TSP(总悬浮颗粒物)作为局地可溶盐补给能力的代用指标分析玉龙浅冰芯pH值对降水量年际变化的响应.在相对湿润年, pH值较低, 若TSP值较高, 则pH值相对较高, TSP值较低, 则pH值较低.在相对干旱年, pH值较高, 若TSP值较高, pH值较高, 若TSP值较低, 则pH值相对较低;在海洋性冰川区, 浅冰芯pH和电导率的变化, 并结合TSP能够有效的反映出冰川作用区干湿的年际变化, 是大气环境状况的敏感指示器.  相似文献   

SOIL EROSION PROCESS RESEARCH AND ITS POTENTIAL IMPACT ON EROSION PREDICTION MODEL DEVELOPMENT     

Chi-hua HUANG Fenli ZHENG 《国际泥沙研究》2005,20(4):350-357

During the past 50 years, many research efforts have been invested in understanding soil erosion process and development of erosion prediction models at various scales. This paper briefly introduces the erosion process and prediction model development in the USA. Especially, this paper focuses on discussing potential impacts of the erosion process on erosion model development, and future directions of the soil erosion process research and process- based model development. 1 DEVELOPMENT O…  相似文献   

干旱区冲洪积扇-冲积平原绿洲浅层地下水质时空变化初步分析--以三工河流域绿洲为例     

肖鲁湘  罗格平  陈曦  许文强 《干旱区地理》2005,28(2):225-228

以三工河流域绿洲为例,分析了干旱区平原绿洲浅层地下水水质的时空变异性。结果表明,该区域地下水质不仅在空间上存在着显著的差异,而且年内及年际差异也很明显：1)冲洪积扇区域地下水质显著优于冲积平原区水质;2)春季地下水质总体好于秋季,且冲积平原区水质恶化程度要快于冲洪积扇区域;3)绿洲地下水质总体呈现下降的趋势,尤其是农业活动强烈且地下水埋深浅的冲积平原区域;4)水文地质条件是造成地下水质时空变异的主要原因,土地利用加剧了其变异性。  相似文献