Atmospheric forcing of the eastern tropical Pacific: A review   总被引：1，自引：8，他引：1  

Jorge A. Amador  Eric J. Alfaro  Omar G. Lizano  Victor O. Magaa 《Progress in Oceanography》2006,69(2-4):101

The increase in marine, land surface, atmospheric and satellite data during recent decades has led to an improved understanding of the air–sea interaction processes in the eastern tropical Pacific. This is also thanks to extensive diagnoses from conceptual and coupled ocean–atmosphere numerical models. In this paper, mean fields of atmospheric variables, such as incoming solar radiation, sea level pressure, winds, wind stress curl, precipitation, evaporation, and surface energy fluxes, are derived from global atmospheric data sets in order to examine the dominant features of the low level atmospheric circulations of the region. The seasonal march of the atmospheric circulations is presented to depict the role of radiative forcing on atmospheric perturbations, especially those dominating the atmosphere at low levels.In the tropics, the trade winds constitute an important north–south energy and moisture exchange mechanism (as part of the low level branch of the Hadley circulation), that determines to a large extent the precipitation distribution in the region, i.e., that associated with the Inter-Tropical Convergence Zone (ITCZ). Monsoonal circulations also play an important role in determining the warm season precipitation distribution over the eastern tropical Pacific through a large variety of air–sea–land interaction mechanisms. Westward traveling waves, tropical cyclones, low latitude cold air intrusions, and other synoptic and mesoscale perturbations associated with the ITCZ are also important elements that modulate the annual rainfall cycle. The low-level jets of the Gulf of California, the Intra-Americas Sea (Gulf of Mexico and Caribbean Sea) and Chocó, Colombia are prominent features of the eastern tropical Pacific low-level circulations related to sub-regional and regional scale precipitation patterns. Observations show that the Intra-Americas Low-Level Jet intensity varies with El Niño/Southern Oscillation (ENSO) phases, however its origin and role in the westward propagation and development of disturbances that may hit the eastern tropical Pacific, such as easterly waves and tropical cyclones, are still unclear. Changes in the intensity of the trade winds in the Caribbean Sea and the Gulf of Mexico (associated with eastern tropical Pacific wind jets) exert an important control on precipitation by means of wind–topography interactions. Gaps in the mountains of southern Mexico and Central America allow strong wind jets to pass over the continent imprinting a unique signal in sea surface temperatures and ocean dynamics of the eastern tropical Pacific.The warm pools of the Americas constitute an important source of moisture for the North American Monsoon System. The northeastern tropical Pacific is a region of intense cyclogenetic activity, just west of the coast of Mesoamerica. Over the oceanic regions, large-scale properties of key variables such as precipitation, moisture, surface energy fluxes and wind stress curl are still uncertain, which inhibits a more comprehensive view of the region and stresses the importance of regional field experiments. Progress has been substantial in the understanding of the ocean and atmospheric dynamics of the eastern tropical Pacific, however, recent observational evidence such as that of a shallow meridional circulation cell in that region, in contrast to the classic concept of the Hadley-type deep meridional circulation, suggests that more in situ observations to validate theories are still necessary.This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific Ocean.  相似文献   

利用卫星测高技术监测厄尔尼诺和拉尼娜现象   总被引：2，自引：0，他引：2  

赵小阳  李建成  王正涛  金涛勇 《海洋测绘》2007,27(1):41-44

利用美国宇航局和法国空间局联合公布的T／P数据（1993-2000年）和Jason-1数据（2002—2006年），由共线法计算了热带太平洋地区海平面高度的变化。根据T／P和Jason-1数据计算的海面月变化异常图，分别研究了和分析了1997-1998年的厄尔尼诺和拉尼娜现象、2002-2003年厄尔尼诺现象的变化发展过程。  相似文献   

河口海岸三维水流数值模型中几种垂向坐标模式研究述评     

陶建峰  张长宽 《海洋工程》2007,25(1):133-142

回顾了近年来国内外河口、近岸海域三维斜压水流数值模式研究的进展,着重讨论了不同垂向坐标下三维水流模式的发展状况以及存在的问题。地形拟合坐标(σ坐标)模式可以很好地拟合床面地形和自由面,已在物理海洋学中被广泛使用。但在地形变化剧烈,尤其在密度层结效应明显的海域,σ坐标模式中的水平压强梯度力误差会引起伪密度流。寻求高精度的数值模式以及更加有效的拟合坐标变换将是值得努力的方向。  相似文献   

El Niño对东亚气候年际异常影响的数值模拟   总被引：3，自引：0，他引：3  

孙旭光  杨修群 《海洋学报》2007,29(5):21-30

根据1949~1998年期间8次显著El Niño事件合成的24个月年际海温异常(SSTAs)和气候平均的海温(SST),利用CCM3分别进行了3个包含10次积分的集合试验,即控制试验(CTRL),热带太平洋海洋全球大气试验(TOGA)以及整个太平洋海洋全球大气试验(TOGA-NP),通过对比分析这3个试验之间的集合模拟结果,揭示了在El Niño不同演变阶段东亚气候年际异常响应结构以及北太平洋年际SSTAs在此过程中的调制作用.结果表明:El Niño发展阶段夏季,东亚地区大气环流异常呈显著的负PJ波列,副热带高压减弱、偏东,东亚夏季风增强,东北和江淮流域降水偏多,华北和长江流域及其以南地区降水偏少;El Niño成熟阶段冬季,东亚大槽加强,东亚北部冬季风加强,西太平洋副热带地区低层有显著的反气旋式异常风场,华南地区降水显著增多;El Niño衰亡阶段夏季东亚气候年际异常型与其发展阶段夏季几乎相反.同时,北太平洋年际SSTAs对El Niño影响东亚气候年际异常有一定的调制作用,使模拟的我国降水异常分布更符合观测.  相似文献   

济阳坳陷博兴洼陷西部沙三段层序地层   总被引：1，自引：0，他引：1  

吴时国  孙永壮  宋建勇 《海洋地质与第四纪地质》2006,26(3):101-107

选取以基准面为参照面的高分辨率层序地层学的理论与分析技术,对博兴洼陷西部沙三段开展层序地层分析工作。在博兴洼陷沙三段识别出5个层序界面和4个较大规模的洪泛面,由此将研究层段划分为4个长期基准面旋回(相当于3级层序),并通过长期旋回内部次级转换面的识别,细分出8个中期旋回(大致相当于4级层序)。通过对比建立了研究区的高分辨率层序地层格架,并分析了各层序的地层发育特征。以层序格架为基础,探讨了研究区各层序的沉积演化特征,建立了辫状三角洲—浊积扇层序发育模式,认为研究区辫状三角洲和浊积扇均具有加积作用特点;斜坡区为辫状三角洲发育区,而洼陷区为浊积扇发育区;中期基准面旋回下降期辫状三角洲发育,上升期浊积扇发育;浊积扇体的发育规模与湖泛规模相关。综合分析认为,浊积扇是形成岩性圈闭的主要储集砂体类型,其发育的有利层位是MSC8、MSC7、MSC6、MSC5旋回的上升半旋回,岩性圈闭发育的有利区是博兴南部斜坡坡折带之下的洼陷区。  相似文献   

Artificial Upwelling of Deep Seawater Using the Perpetual Salt Fountain for Cultivation of Ocean Desert     

Shigenao Maruyama  Koutaro Tsubaki  Keisuke Taira  Seigo Sakai 《Journal of Oceanography》2004,60(3):563-568

Deep seawater in the ocean contains a great deal of nutrients. Stommel et al. have proposed the notion of a “perpetual salt fountain” (Stommel et al., 1956). They noted the possibility of a permanent upwelling of deep seawater with no additional external energy source. If we can cause deep seawater to upwell extensively, we can achieve an ocean farm. We have succeeded in measuring the upwelling velocity by an experiment in the Mariana Trench area using a special measurement system. A 0.3 m diameter, 280 m long soft pipe made of PVC sheet was used in the experiment. The measured data, a verification experiment, and numerical simulation results, gave an estimate of upwelling velocity of 212 m/day. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Sediment–water interactions of natural oestrogens under estuarine conditions     

J. C. Bowman  J. L. Zhou  J. W. Readman 《Marine Chemistry》2002,77(4)

The natural human female hormones oestrone and 17β-oestradiol have been implicated in the disruption of endocrine systems in some wildlife adjacent to sewage effluents. The sorption behaviour of these two compounds under estuarine conditions was studied by spiking either 2.55 μg of oestrone or 2.65 μg of 17β-oestradiol in kinetic experiments. In equilibrium experiments, 3 ng of oestrone or 3.2 ng of 17β-oestradiol was added in each of the centrifuge tubes. Sorption onto sediment particles was relatively slow, with sorption equilibrium being reached in about 70 and 170 h for oestrone and 17β-oestradiol, respectively. The effects of a variety of environmental parameters on sorption were studied including salinity, sediment concentration (SC), the presence of a third phase, particle size and, also, surfactant concentrations. Results show that although salinity did not induce any statistically significant effect on the sorption of 17β-oestradiol, it did statistically enhance the sorption of oestrone, and a salting constant of 0.3 l mol⁻¹ was derived. The partition coefficient for both compounds decreased with increasing sediment concentration, a phenomenon that has been widely reported and attributed to the presence of colloids (which could enhance dissolved concentrations). In this paper, the true partition coefficients for sediment particles (K_p^true) and colloidal particles (K_c^true) have been calculated, and a K_p^true value of 141 and 102 ml g⁻¹ was obtained for oestrone and 17β-oestradiol, respectively. In addition, K_c^true values for oestrone (222×10² ml g⁻¹) and 17β-oestradiol (135×10² ml g⁻¹) were two orders of magnitude higher than their respective K_p^true values, suggesting that the colloidal particles are significantly stronger sorbents for natural oestrogens than sediment particles. Particles of different sizes were found to have different partition coefficients due to the strong relationships between partition coefficients for the two compounds and particulate organic carbon (POC) contents and specific surface areas (SSAs). The presence of a surfactant was shown to reduce the partition coefficients for the two compounds, although its concentrations being used were higher than those normally found in the natural environment.  相似文献   

基于规则波波形的超声波非接触测量有关问题探讨     

叶家玮  孙晓梅 《海洋工程》1996,(3)

波浪波形的非接触测量近年来获得广泛的应用。本文以规则波为讨论对象，针对介质为空气的超声波测量方式进行波形测量误差分析，并结合实验室和实船试验进行对比分析。理论分析表明：在规则波取为坦谷波和ＳＴＯＫＥＳ波的前提下，超声波技术几乎产生相同的最大误差。定量分析表明，在对测量精度限制的条件下，对文中提及的各项参数应作有效的控制  相似文献   

崂山花岗岩地区含锶、偏硅酸矿泉水的形成机理   总被引：1，自引：0，他引：1  

赵广涛  曹钦臣  孙悦鹏 《中国海洋大学学报(自然科学版)》1996,(2)

报道了崂山花岗岩地区矿泉水的特征。指出其矿泉类型为含锶、偏硅酸型，并讨论了其形成机理。  相似文献   

城市与工程测量EDM导线技术标准的分析   总被引：1，自引：0，他引：1  

严伯铎  任晔平 《海洋测绘》2006,26(4):15-20

基于导线测量误差理论与电磁测距(EDM)导线的特性,分析讨论了城市与工程测量EDM导线的各项技术参数,提出了各级EDM导线技术标准的建议,通过计算验证所给出的这些技术指标是合理可靠的。  相似文献