径向风和反射率直接同化对一次梅雨锋暴雨模拟的影响

利用中尺度数值模式WRF及其三维变分同化系统,采用NCEP再分析资料和合肥新一代天气雷达资料,针对2003年7月4—5日发生在江淮流域的一次梅雨锋暴雨过程,分析了直接同化雷达径向风和反射率对降雨模拟的影响。结果表明：1）直接同化雷达径向风能够改进低层辐合带的位置、增加低层气旋性扰动,增强低空急流核;改进垂直速度有利于对...     

SATELLITE-BASED ANALYSIS ON THE CONCENTRIC EYEWALL REPLACEMENT CYCLES OF SUPER TYPHOON MUIFA (1109)

Multisatellite data is used to analyze the characteristics of three eyewall replacement cycles (ERCs) during the lifetime of Typhoon Muifa (1109). Spiral rainbands evolutions, concentric eyewall (CE) structure modes, CE durations, and intensity changes are discussed in detail. In addition, an ERC evolution model of Typhoon Muifa is given. There are four main findings. (1) The outer spiral rainband joins end to end to form the outer eyewall after it disconnects from the original (inner) eyewall. The inner eyewall weakens as the outer eyewall becomes axisymmetric and is intensified. The contraction of the outer eyewall causes the inner eyewall to dissipate rapidly. Finally, the ERC ends with an annular eyewall or spiral rainbands. (2) Although the CE duration times of Typhoon Muifa’s three ERCs covered a large range, the CE structures were all maintained for approximately 5 h from the formation of the axisymmetric outer eyewall to the end of the cycle. (3) There is no obvious precipitation reflectivity in the eye or moat region for the subsidence flow. The convection within the two eyewalls is organized as a radially outward slope with increasing height. (4) Typhoon intensity estimation results based on ADT may not explain the intensity variations associated with ERC correctly, while the typhoon’s warm core data retrieved from AMSU-A works well.     

PRELIMINARY STUDY OF THE ASSESSMENT OF METHODS FOR DISASTER-INDUCING RISKS BY TCs USING SAMPLE EVENTS OF TCs THAT AFFECTED SHANGHAI

Hazard factors,hazard-bear1ing objects,disaster-developing environment,and disaster-preventing capability play key roles in the formation of Tropical Cyclone (TC) disasters.Of all of these,the most important is the intensity of hazard factors (risk sources).In this study,this intensity is uniformly defined by the probability of hazard factors;then a relationship is established between disaster risk intensity and hazard factors.The exceedance probability of various hazard factors,including frequency and timing,scope of wind and rain,and maximum wind and rain of impacting TC cases,are calculated using data from TCs that impacted Shanghai from 1959–2006.The relationship between disaster situation and risk probability of hazard factors is analyzed,and the indices and model of TC disaster assessment are established based on the results.The process maximum wind speed and maximum daily precipitation are very important in TC-related disaster formation in Shanghai.The results of disaster indices coordinate with the results of the assessment model,and both can show the extent of probability of a TC disaster.Tests using TC data in 2007 and 2008 show that disasters caused by TC Krosa (0716) would be more serious than those by TC Wipha (0713),and that TC Fung Wong (0808) would have a weak impact.Real-life situations validate these results.     

国外航空物探系统集成技术回顾(2015～2020)

梳理了 2015～2020年之间国外主要的航空物探系统集成技术的现状和进展情况.在这一时期,一些旧的系统进行了改进,也有一些不再适合市场需要而被淘汰.新的系统集成方法不断涌现:随着修正算法的改进,磁梯度吊舱开始被广泛应用;无人机系统的飞行控制能力和负载能力显著提升,已应用于磁、电、重、伽马能谱各领域;SQUID磁张量、...     

"8·22"非雷击事故的鉴定与思考

2006年8月22日下午,桐庐R公司职工厨房建造工地上钢筋工余某意外死亡。本文根据现场勘察、取证情况,结合雷电防护理论,对事故作了分析与鉴定,并提出相关问题的思考。     

高浓度的温室气体和极地平流层云：古新世末次高温期高纬度运物群迁移的可能答案

古新世末次高温期（ＬＰＴＭ）是始于５５．５Ｍａ、持续约１００～１４０ｋａ的短期变暖事件 ,属于晚古新世—早始新世时期的全球性温暖气候。古气候指标表明 ,高纬度气温在ＬＰＴＭ时可能达到新生代期间的最高值。陆地δ１８Ｏ记录显示出ＬＰＴＭ时期北美洲年平均气温（ＭＡＴ）增加了４℃ ,海洋δ１８Ｏ记录显示出深海温度和高纬度海洋表层温度（ＳＳＴｓ）增加了４～６℃ ,而热带ＳＳＴｓ没有什么变化。这种集中在高纬度地区的突然变暖现象 ,目前仍然没有令人信服的解释。与ＬＰＴＭ时期高纬度气候极度变暖同步进行的是有大量的哺乳类在…     

环境风垂直切变与登陆台风强度变化关系的统计分析

为了了解环境风垂直切变在登陆台风强度突变下所起的作用,利用1990-2004年登陆中国的111个台风的强度、登陆位置以及NCEP/NCAR每日4次等压面风场等资料,分析了风速垂直切变对台风登陆过程中强度变化的影响.结果表明,与海盆中相比,环境风垂直切变与登陆台风强度的线性相关性减小,滞后的时间长度减短;环境风垂直切变与滞后6～18 h的台风强度有不可忽视的相关性,与滞后6 h的台风强度相关最佳,相关系数为0.215;对于显著增强的登陆台风,其所处的环境风垂直切变不太大,平均在9 m·s-1以下,反之当环境风垂直切变在9 m·s-1以上时,登陆台风的强度也有可能显著减弱;与在华南登陆的台风相比,在华东登陆的台风其减弱型样本相对更多,其强度受风速垂直切变影响衰减得更快.     

沙湾县翠山公园不稳定斜坡地质灾害特征分析

在充分调查、收集前人工作成果及相关资料的基础上,对新疆沙湾县翠山公园不稳定斜坡灾害的实地勘查,基本查明研究区不稳定斜坡的地质环境条件、灾害特征及影响因素,且根据三种情况对滑坡灾害进行了稳定性计算,结果可知:在自重、地震工况下,该不稳定斜坡体均处于稳定状态;暴雨工况下,该不稳定斜坡不稳定,综合评价,该不稳定斜坡稳定性差。研究结果为下一步灾害治理提供了可靠的科学依据。     

东天山北麓平原区地下水化学特征研究

通过分析东天山北麓平原区160组地下水化学样品检测结果,采用舒卡列夫分类法和Piper三线图解法,研究了地下水化学分带特征。南部山前冲洪积砾质平原地下水化学类型为HCO_3·SO_4型,中部细土平原逐渐向SO_4·HCO_3型过渡,北部沙漠区以SO_4·Cl型为主,地下水溢出带为Cl·SO_4型。根据水化学剖面分析地下水各组分含量在径流途经中的变化趋势,分析结果表明,沿地下水径流方向由南向北,地下水中的硫酸盐、氯化物和钠都呈现出逐渐增大的变化规律,导致了水中溶解性总固体逐渐增大,水质逐渐变差。