Atmospheric forcing of the eastern tropical Pacific: A review

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.     

0515台风"卡努"影响浙江的强风分析

本文对0515台风“卡努”登陆浙江后,强度减弱为强热带风暴,对影响浙江沿海海面及沿海地区的外围风速远强于近风暴中心风速进行了分析,分析结果表明:副热带高压的加强、对流层中下层急流的动量下传、高空较强的下沉气流和台风外围气压梯度力迅猛增大的共同作用,是造成本次风暴外围风速远强于近风暴中心风速的重要原因。     

高陡土坡喷锚（土钉墙）支护施工技术

通过长沙电力学院西区永久性锚拉挡墙施工实例，介绍喷锚(土钉墙)的施工方法，质量控制关键点等施工技术．     

索马里急流的年际变化及其对半球间水汽输送和东亚夏季降水的影响

利用美国国家环境预报中心和美国国家大气科学研究中 心（NCEP/NCAR）再分析月平均气候资料以及Xie和Arkin分析的月平均降水资料（1968～199 8年），针对索马里低空急流（SMJ）的年际变化及其对东亚夏季降水的影响问题展开了分析 研究. 结果揭示，SMJ作为最主要的越赤道气流，对两个半球间水汽输送起最关键的作用， 它把水汽从冬半球输送到夏半球. 夏季SMJ的年际变化有全球范围内的环流异常与之相联系 ，特别是东亚沿岸的波列状异常分布、南亚高压以及澳大利亚以南的偶极型异常分布；它 也同春季的北印度洋等海区的海温异常有密切关系. 研究还表明，春季SMJ的年际变化对东 亚夏季降水和大气环流有显著影响，由于SMJ影响的超前性，因此它在东亚夏季气候预测上 有重要意义.     

旋喷固结体的物理力学性状研究

通过单轴抗压试验、剪切试验、变形试验及渗透性试验等方法，对旋喷固结体的物理力学性状和渗透性进行了研究。结果表明：旋喷固结体具有良好的物理力学性质和较低的渗透性，可完全改变天然土的性质。     

高压旋喷桩复合地基在高层住宅楼中的应用

以郑州市某高层住宅楼工程为例,介绍了高压旋喷桩复合地基的设计计算和施工方法,经静荷载试验和建筑物沉降观测,复合地基的承载力可以满足设计要求,说明高压旋喷桩复合地基可以成功地用于高层住宅楼的建筑中.     

夏季亚洲高空急流纬向非对称变异与北大西洋海温和欧亚陆面热力异常的可能联系

基于1979~2015年ERA-Interim再分析资料,分析了夏季亚洲高空急流纬向非对称变异特征及其可能的外强迫因子。研究发现夏季亚洲200 hPa纬向风异常EOF第二模态（方差贡献为16.4%）主要表现出了急流纬向非对称的空间异常形态,反映了西亚和东亚区域急流南北偏移的反位相变化。通过进一步的诊断分析,我们发现急流纬向非对称变异与北大西洋海表温度（简称海温）和欧亚陆面热力异常可能存在一定的联系。北大西洋三极型海温异常会激发出向下游传播的异常波列,夏季该波列在欧亚大陆上空的异常环流中心与急流纬向非对称相关的异常环流中心对应一致,其中东欧平原的异常反气旋和巴尔喀什湖附近的异常气旋对西亚急流变化存在影响,东亚地区急流的变化与贝加尔湖北部异常气旋和贝加尔湖南部的异常反气旋有关。对比欧亚土壤湿度关键区内垂直环流,陆面热力异常可能会改变局地环流进而影响急流变异,且这种影响存在区域差异。     

流动环境中倾斜浮力射流的积分方法

给出了基于积分方法的一种倾斜浮力射流的数学模型,且流速、密度和浓度差剖面假定为高斯分布,并导出了用来封闭该数学模型的较为完全的掺入率公式.用计算精度较高的有限分析法计算这类定解问题,计算结果与试验资料基本吻合.     

华南春季强风暴背景流场的若干特征

本文利用常规探测资料,分析了1983年3月25日发生在珠江三角洲地区的一次强对流天气过程背景流场的几个重要特征,如高空急流的结构与变化、辐散风场及与之相联系的背景次级环流、风场垂直切变和水平切变等.     

冬季青藏高原对东移大槽动力影响的研究：Ⅲ.模拟试验结果的分析

具体分析了本文Ⅱ的模拟试验结果。结果表明，该试验较清楚地再现了青藏高原地形对西风气流的影响，也显示了不同地形、急流的有无、强度和位置以及初始槽强度和基本气流斜压性的强度对东移槽的影响。这些结果有的清楚地再现了过去熟知的或还不很清楚的地形影响事实，有的可为东移槽的预报提供着眼点。