Variational iteration solving method for El Nio phenomenon atmospheric physics of nonlinear model

1 IntroductionThe El Ni’o atmospheric physics oscillation is anabnormal phenomenon involved in the tropical Pacificocean- atmosphere interactions. Studies on the El Ni(ophenomenon are very attractive (Lin et al., 2000; Linet al., 2001, 2002; Wang, 2001; Feng et al., 2001;Feng et al., 2002; Liu et al., 2002; Wei and Chen,2003; Xie et al., 2002; Zhu et al., 2002; Pu et al.,2003; Gu et al., 2004; Yu and Liu, 2004). Lin and Mo(2004), Mo and Lin (2004) and Mo et al. (2004) alsostudied a s…     

论桩基施工中流砂现象处理

地下水流动对土体产生渗透力；当渗透力大于土体的抗剪强度，土体破坏，也就是当施工造成地下水水力坡度超过砂层的临界水力坡度即产生流砂现象．运用水文地质工程地质学方面的原理其处理方法有两类：—是莫尔一库仑法：即c法和φ法；二是临界水力坡度法(Ic法)．     

前兆观测中的远场效应及其成因机制的初步探讨

在近２年的前兆观测实践中，我们发现了一种十分有趣的，奇特的现象，在１９９６年３月１９日新疆阿图什６．９级强震发生前和１９９７年３￣４月新疆伽师６级强震群发生前，在远隔２５００公里外的四川地区观测到了多种前兆手段的群体突变事件。我们称它为强震的“远场效应”。本文还对它的成因机制作了初步的探讨。     

Multivariate nonparametric resampling scheme for generation of daily weather variables

A nonparametric resampling technique for generating daily weather variables at a site is presented. The method samples the original data with replacement while smoothing the empirical conditional distribution function. The technique can be thought of as a smoothed conditional Bootstrap and is equivalent to simulation from a kernel density estimate of the multivariate conditional probability density function. This improves on the classical Bootstrap technique by generating values that have not occurred exactly in the original sample and by alleviating the reproduction of fine spurious details in the data. Precipitation is generated from the nonparametric wet/dry spell model as described in Lall et al. [1995]. A vector of other variables (solar radiation, maximum temperature, minimum temperature, average dew point temperature, and average wind speed) is then simulated by conditioning on the vector of these variables on the preceding day and the precipitation amount on the day of interest. An application of the resampling scheme with 30 years of daily weather data at Salt Lake City, Utah, USA, is provided.     

沈阳地区沙尘天气分析

本文总结了沈阳地区沙尘天气的时空分布特点，从天气条件、地表自然条件(沙源)两方面分析了沈阳地区沙尘天气的成因，总结了沈阳地区预报沙尘天气时应参考的5个因素。     

广西中短期极端温度客观预报方法研究

利用欧洲中心(ECMWF)数值预报产品和常规资料,应用MOS预报方法和多元线性回归技术,研究建立了广西90个站1~7d的最高、最低温度预报方程,试报检验效果较好,预报结果在大多数情况下是可用的或是可参考的,为业务提供了有效的省级客观预报指导产品,对误差特点进行了分析并提出了改进方法。     

2008年广西严重低温雨雪冰冻天气过程分析

利用T213、ECMW F数值预报资料和MICAPS提供的常规观测资料,对这次极端天气事件成因进行分析,表明造成这次长时间低温雨雪冰冻天气的主要原因有:(1)北半球东亚倒Ω流型使大气环流长时间稳定,使北支、南支锋区偏南,极地冷空气不断补充南下影响到江南、华南,华南静止锋在沿海长时间维持,锋区强度大;(2)南支槽活跃,西南暖湿气流持续向我国南方输送,冷暖空气在华南上空交汇,导致广西出现长时间的降水;(3)逆温层维持时间长,长时间的降水普遍以小雨为主,容易形成过冷水滴,雨淞范围从贵州、湖南南扩至广西北部,造成道路结冰、电线积冰等次生灾害,灾情严重。     

Summer weather characteristics on the Grove Mountain of East Antarctica

The summer weather characteristics of the Grove Mountain, East Antarctica, are presented based on the data obtained by Chinese National Antarctic Expedition (CHINARE) in January 1999. The result shows that the pattern of daily variation of temperature and the prevailing wind direction in Grove is similar to that of Zhongshan Station. However, the daily range of temperature and strong wind frequency are much higher than those of Zhongshan Station. The change of wind direction is close to the weather system that impacted the Grove Mountain. The warm and wet air from northern parts often causes the precipitation. The clear weather appears when controlled by eastern winds in January.     

川西盆地雾和能见度的气候特征及其对飞行的影响

利用川西盆地广汉机场气象台1986年1月~1995年12月共10 a地面观测资料,对广汉机场低能见度的生消时间、持续时间和能见度的年季节变化及其日变化做了统计分析,研究广汉机场全年能见度的飞行气候特征,特别是低能见度气候特征对飞行的影响。结果表明,能见度日变化特征表现为:白天早、晚时段能见度较低,午后能见度达到最高。能见度的季节变化特征表现为:冬(12,1,2月)、春季(3,4,5月)能见度较低,而夏(6,7,8月)、秋季(9,10,11月)能见度较高。冬季能见度的变化主要受辐射雾影响,夏季能见度的变化主要受降水的影响,随着降水强度的变化而变化,低能见度时间短暂。各标准低能见度逐时频率的日变化特征在各季基本相似,低能见度高频率区均出现在早晨到上午,低频率区均出现在下午。     

地基微波辐射计探测在黄河上游人工增雨中的应用

利用2003、2004年夏秋季在青海省河南县的地基双频段微波辐射计连续观测资料,在实施系统探测实验以进行辐射亮温值(TB(23.87),TB(31.65))与大气汽态总水汽含量(Q)和云中积分液态水含量(L)值反演处理的基础上,分析了黄河上游河曲地区的云水特征,并进行了降水预测及人工增雨作业指标的探讨。结果表明:在黄河上游河曲地区,7—9月纯晴天无云天气条件下,L值基本为0,表明了统计回归反演的显著性。多云条件下Q值和L值分别在3.76~4.75g·cm-2、227.34~859.42g·m-2的范围内。可降水云天气,Q值在5.23~8.65g·cm-2间,L值在421.18~1016.37g·m-2的范围内;积雨云个例分析表明,在降雨开始前近5小时的降雨酝酿期内,Q及L的增加有明显的波动,但在对流云出现并发展时,Q和L总是急剧上升,在降雨前达到一峰值;由河南站和西安站的Q、L值比较差异可以看出,Q、L值受水汽输送、地形等因素的影响,黄河上游河曲地区的人工增雨潜力有显著的优势;所计算出的降水预测阈值,可作为该地区人工增雨作业指标的参考。