甘肃夏季特强沙尘暴分析     

王锡稳  黄玉霞  刘治国  魏锋  张铁军 《气象科技》2007,35(5):681-686

夏季沙尘暴的气候特征表明,夏季是甘肃省沙尘暴的次多发季节,主要集中在民勤、鼎新、金塔。通过对一次罕见的甘肃省夏季强沙尘暴天气分析发现:高空小槽、切变线、热低压是引发夏季沙尘暴的主要天气系统,而春季沙尘暴一般是大尺度天气系统造成的;夏季沙尘暴发生前期高空急流反映并不明显,急流风速的突然加大和沙尘暴几乎同时发生,这是夏季沙尘暴预报的难点之一;沙尘暴发生前8~12 h的螺旋度场对沙尘暴预报有较好的指示意义,正值越大,沙尘暴越强,但当沙尘暴与强降水同时发生时,沙尘暴区螺旋度值明显小于强降水中心螺旋度值。  相似文献   

鹤壁市农村集体土地所有权确权登记发证工作通过省级验收简     

张成岭  周春霞 《河南国土资源》2014,(1):26

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花粉预报服务社会经济效益估算分析   总被引：3，自引：1，他引：2  

吴振玲  刘爱霞  白玉荣  刘彬贤  王春兰 《气象》2011,37(5):626-632

研究花粉预报服务经济效益评估方法,对认识专业预报服务的公众价值及其潜在的社会效益有着积极的意义.主要使用的估算方法为,针对影响天津花粉预报服务经济效益的4个重要因素,花粉预报准确率、预报服务时效性、预报服务信息的覆盖率和花粉敏感人群的预防能力,设定预报准确率(Af)、预报时效率(Tf)、信息覆盖率(Ic)和患者的预防能...  相似文献   

Analysis of Mesoscale Convective Systems Associated With a Warm-Sector Rainstorm Event Over South China   总被引：1，自引：1，他引：0  

张晓美  蒙伟光  张艳霞  梁建茵 《热带气象学报(英文版)》2011,17(1):1-10

With multiple meteorological data, including precipitation from automatic weather stations, integrated satellite-based precipitation (CMORPH), brightness temperature (TBB), radar echoes and NCEP reanalysis, a rainstorm event, which occurred on May 26, 2007 over South China, is analyzed with the focus on the evolution characteristics of associated mesoscale-β convective systems (Mβcss). Results are shown as follows. (1) The rainstorm presents itself as a typical warm-sector event, for it occurs within a surface inverted trough and on the left side of a southwesterly low-level jet (LLJ), which shows no obvious features of baroclinicity. (2) The heavy rainfall event is directly related to at least three bodies of Mβcss with peak precipitation corresponding well to their mature stages. (3) The Mβcss manifest a backward propagation, which is marked with a new form of downstream convection different from the more usual type of forward propagation over South China, i.e., new convective systems mainly form at the rear part of older Mβcss. (4) Rainstorm-causing Mβcss form near the convergence region on the left side of an 850-hPa southwesterly LLJ, over which there are dominantly divergent air flows at 200 hPa. Different from the typical flow pattern of outward divergence off the east side of South Asia High, which is usually found to be over zones of heavy rains during the annually first rainy season of South China, this warm-sector heavy rain is below the divergence region formed between the easterly and southerly flows west of the South Asian High that is moving out to sea. (5) The LLJ transports abundant amount of warm and moist air to the heavy rainfall area, providing advantageous conditions for highly unstable energy to generate and store at middle and high levels, where corresponding low-level warm advection may be playing a more direct role in the development of Mβcss. As a triggering mechanism for organized convective systems, the effect of low-level warm advection deserves more of our attention. Based on the analysis of surface mesoscale airflow in the article, possible triggering mechanisms for Mβcss are also discussed.  相似文献   

The Impact of Air-Sea Interactions on Typhoon Structure   总被引：1，自引：1，他引：0  

蒋小平  刘春霞  莫海涛  汪宇翔 《热带气象学报(英文版)》2011,17(1):87-92

In this work,the results of a coupled experiment and an uncoupled experiment conducted in one of our former works are used to analyze the impact of air-sea interactions on the structure of typhoons.Results reveal that typhoon-induced SST decreases to reduce the latent heat fluxes transporting from the ocean to the atmosphere and cause the flux of sensible heat to transfer downward from the atmosphere to the ocean.Such SST reduction also has remarkable impacts on the typhoon structure by making the typhoon more axisymmetric,especially in the middle and high levels.This study also analyzes the basic characteristics of symmetric typhoon structure.  相似文献   

Prediction of sea fog of Guangdong coastland using the variable factors output by GRAPES model     

黄辉军  黄健  刘春霞  袁金南  毛伟康  廖菲 《热带气象学报(英文版)》2011,17(2):166-174

By analyzing the NCEP 1°×1° reanalysis (2004–2008), a number of predictors (factors of variables) are established with the output from the GRAPES model and with reference to the sea fog data from observational stations (2004–2008) and field observations (2006–2008). Based on the criteria and conditions for sea fog appearance at the stations of Zhanjiang, Zhuhai and Shantou, a Model Output Statistics (MOS) scheme for distinguishing and forecasting 24-h sea fog is established and put into use for three repres...  相似文献   

北京市朝阳区大气降尘磁学特征及对空气污染物浓度的指示   总被引：3，自引：0，他引：3       下载免费PDF全文

乔庆庆  张春霞  李静  李泓  黄宝春 《地球物理学报》2011,54(1):151-162

应用环境磁学方法研究了2008年奥运会前后北京市朝阳区大气降尘及对照点表土样品的磁学特征.结果表明,所有样品中载磁矿物主要为低矫顽力的亚铁磁性矿物(主要为磁铁矿).但大气降尘样品的磁性颗粒粒度较表土偏粗;磁性矿物含量高于表土样品,大气降尘除来自于自然源外,更多为来自于人为因素的结果.大气降尘磁化率与空气污染物浓度随时间...  相似文献   

加速溶剂萃取-气相色谱/气相色谱-质谱法测定土壤中7种多氯联苯   总被引：3，自引：2，他引：1  

陈卫明  李庆霞  张芳  何小辉  张勤 《岩矿测试》2011,30(1):33-39

建立了土壤样品中7种多氯联苯(PCB 28、PCB 52、PCB 101、PCB 118、PCB 138、PCB 153、PCB 180)的分析方法。土壤样品通过加速溶剂萃取、磺化法结合Florisil固相萃取小柱净化、电子捕获检测器气相色谱分析测定,并结合气相色谱-质谱进一步确证。结果表明,方法回收率为80.06%～100.28%,相对标准偏差(RSD,n=6)为1.01%～6.28%,检出限为0.15～0.50μg/kg。用优化的方法测定复杂基质的土壤样品中多氯联苯,具有提取效率高、净化效果好、结果准确可靠、对环境污染小等优点。  相似文献   

不同类型生物土壤结皮固氮活性及对环境因子的响应研究   总被引：2，自引：1，他引：1  

苏延桂  李新荣  赵昕  李爱霞  陈应武 《地球科学进展》2011,26(3):332-338

利用乙炔还原法对腾格里沙漠东南缘沙坡头地区3种生物土壤结皮(藻结皮、地衣结皮和苔藓结皮)的固氮活性及生物结皮固氮活性对模拟不同降雨量(1、3和5 mm)、温度(13、24和28℃)和光强(0、400和1000μmol/(m2·s))的响应进行研究.结果表明:不同类型生物结皮的固氮活性差异显著,依次为:藻结皮(16.6 ...  相似文献   

陕西省凤县温江寺金矿地质地球化学特征及找矿          下载免费PDF全文

代军治袁旭东  陈少迅李永勤  原连肖王 涛 郭 路 刘莉霞 蒋 蕊 《中国地质》2011,38(3):692-700

温江寺金矿是西秦岭东部地区三叠纪地层中新发现的一个金矿。容矿地层主要是钙质板岩和含炭钙质板岩。矿(化)体呈透镜状、扁豆状分布于钙质板岩和炭质板岩中。区内成矿元素为Au、As、Sb、Hg、Pb、Zn等低温蚀变组合,地质特征显示出微细浸染型金矿特征。各类岩(矿)石的地球化学分析表明,从矿石到泥质板岩再到花岗岩脉,Al2O3和K2O+Na2O含量逐渐升高,而CaO含量、K2O/Na2O具降低趋势;矿石中As、Bi、Co、Ni、Cu、W、V、Tu、U等微量元素含量和ΣREE、LREE/HREE、稀土配分模式与容矿地层相近,而与花岗岩脉不同。地球化学特征显示,温江寺金矿成矿物质主要来源于容矿地层,与岩浆活动关系不密切。该金矿的发现,使得西秦岭三叠系沉积建造中金矿找矿有进一步向东延伸的可能。  相似文献