Application of LPW and SAI SAFNWC/MSG satellite products in pre-convective environments     

Miguel A. Martinez  Mercedes Velazquez  Marcelino Manso  Irene Mas 《Atmospheric Research》2007,83(2-4):366-379

The Spinning Enhanced Visible and Infrared Imagery (SEVIRI) instrument, on board the Meteosat Second Generation (MSG), is a radiometer with eight infrared (IR) spectral bands. Seven of these channels are used to retrieve Layer Precipitable Water (LPW) and Stability Analysis Imagery (SAI). Both products are the PGE07 and the PGE08 of SAFNWC (Satellite Application Facility on support to Nowcasting and Very Short-Range Forecasting). The authors at Instituto Nacional de Meteorología (INM) have developed the LPW and SAI algorithms, in the SAFNWC framework. Both products are retrieved using statistical retrieval based on neural networks. The main advantage of these algorithms versus physical retrieval algorithms is the independence from the Numerical Weather Prediction (NWP) models. The LPW provides information on the water vapor contained in a vertical column of unit cross-section area in three layers in the troposphere (low, middle and high) and in the total layer in cloud free areas. The SAI provides estimations of the atmospheric instability in cloud free areas, in particular the Lifted Index (LI).The stability and precipitable water obtained with both products are routinely generated every 15 min at a satellite horizontal resolution of 3 km in NADIR. A significant advantage of these MSG products, compared to traditional measurements such as radiosondes, is their ability to measure high resolution temporal and spatial variations of atmospheric stability and moisture in pre-convective environments. The main disadvantage is that they do not have the vertical resolution of radiosonde. The MSG moisture and stability time trend fields are especially useful during the period preceding the outbreak of convection due to the high resolution. Once the outbreak of convection occurs, the products calculated in the clear air pixels surrounding the convective system will allow to foresee the evolution of the convection.  相似文献   

论工程岩体完整性的评价方法     

胡文寿  张显志 《地球科学与环境学报》2001,23(3):50-54

目前国内外对工程岩体完整性的评价方法很多,均从某一侧面间接反映了岩体的完整程度,缺乏科学性.结合工程勘察实践及相关学科的研究,对岩体完整性评价,建立了KY、RID新公式,提高了工程岩体完整程度评价方法的科学性.  相似文献   

试论测绘人才资源发展策略     

张宝利  刘德馨  孙颖 《地理信息世界》2001,(1)

本文通过对测绘人才资源现状的分析 ,从影响测绘生产单位人才资源开发与管理的发展策略的因素出发 ,研究探讨如何选择测绘人才资源开发与管理的发展策略。  相似文献   

Experimental study of ore gabbro liquid immiscibility     

SANG Zunan    XIA Bin  ZHOU Yongsheng & JIN Zhenmin . Guangzhou Institute of Geochemistry  Chinese Academy of Sciences  Guangzhou  China  . Wuhan University  Wuhan  China  . Institute of Geology  China Seismological Bureau  Beijing  China  . Faculty of Earth Sciences  China University of Geosciences  Wuhan  China 《中国科学D辑(英文版)》2005,48(4):496-505

The magma immiscibility is that an originallyuniform magma split into two liquids with differentcompositions and properties because of the changes oftemperature, pressure and composition in the mag-matic processes. The phenomenon is ubiquitous in thenature and industrial production. For example, magmaimmiscibility has been widely regarded as the mainmechanism of formation of the Cu-Ni sulphide depositAs early as the 1920s, some geologists[1] noted that anon-silicate magma, which is mainly com…  相似文献   

关于产业结构,布局,政策一体化研究：以上海工业发展为例     

杨万钟 《云南地理环境研究》1991,3(1):15-21

本文论述了产业结构、产业布局和产业政策一体化研究的辩证关系,指出经济地理必须拓展研究领域,不能局限于产业布局的狭窄范围内,而应把结构、布局和政策综合进行研究,才能提高研究成果的科学水平。产业结构和产业布局是一个事物的两个侧面,全国产业合理布局是优化产业结构的前提,地区产业结构合理化又是优化产业布局的前提。而加强产业政策研究又是实现产业结构和合理布局调整的必要保证。文内以上海市的实例进行系统分析与论述。  相似文献   

TPC 及 DLC理论在旅游产品再开发中的应用——昆明市案例研究   总被引：23，自引：1，他引：22  

戴光全  吴必虎 《地理科学》2002,22(1):123-128

从旅游产品再开发的角度出发,应用市场营销学的TPC理论和旅游地理学的DLC理论,对昆明市的病例进行分析,提出了昆明市旅游产品再开发战略的方向、原则和发展重点。  相似文献   

The Impact of Precipitation Scavenging on the Transport of Trace Gases: A 3-Dimensional Model Sensitivity Study   总被引：1，自引：0，他引：1  

Paul J. Crutzen  Mark G. Lawrence 《Journal of Atmospheric Chemistry》2000,37(1):81-112

With the global Chemistry-Transport model MATCHsensitivity simulations were performed to determinethe degree to which especially upward transport ofgases from the earth's surface is limited byconvective and large-scale precipitation scavenging.When only dissolution of species in the liquid phaseis taken into account, mixing ratio reductions in themiddle and upper troposphere by 10% arecalculated for gases with a Henry's Law constant H of10³ mol/l/atm. The removal increases to 50% forH = 10⁴ mol/l/atm, and to 90% for H =10⁵ mol/l/atm. We also consider scavenging by theice phase, which is generally much less efficient thanby the aqueous phase. In fact, rejection of gases fromfreezing water droplets may be a source of trace gasat higher altitudes.H₂O₂ and the strong acids (H₂SO₄,HNO₃, HCl, HBr, HI) have such large solubilitiesthat they become largely removed by precipitation.When significant concentrations of these gases andsulfate aerosol exist above the liquid water domain ofthe atmosphere, they have likely been produced thereor at higher altitudes, although some could have comefrom trace gas rejection from ice particles or fromevaporating hydrometeors. Several other gases areaffected by precipitation, but not strongly enough toprevent fractional transfer to the middle and uppertroposphere: e.g., HNO₄, HNO₂ at pH 5,CH₂O, the organic acids at pH 6,CH₃SOCH₃, HOCl, HOBr, and HOI. NH₃ islargely removed by liquid phase scavenging at pH 7 and SO₂ atpH 7. At pH less thanabout 6, upward transport of SO₂ should largelydepend on the efficiency of oxidation processes in thewater droplets by O₃ and H₂O₂.Most gases have solubilities which are too low forsignificant precipitation scavenging and aqueous phaseoxidation to occur. This holds, e.g., for O₃, CO,the hydrocarbons, NO, NO₂, HCN, CH₃CN,CH₃SCH₃, CH₃O₂H, CH₃CHOandhigher aldehydes, CH₃OH and higher alcohols,peroxyacetylnitrate (PAN), CH₃COCH₃ andother ketones (note that some of these are not listedin Table I because their solubilities are below 10mol/l/atm). Especially for the short-lived gases,transfer from the boundary layer to the middle andupper troposphere is actually promoted by the enhancedupward transport that occurs in clouds.  相似文献   

Ground motion prediction with the empirical Green's function technique: an assessment of uncertainties and confidence level     

Ronan Pavic  Martin G. Koller  Pierre-Yves Bard  Corinne Lacave-Lachet 《Journal of Seismology》2000,4(1):59-77

An assessment of uncertainties for ground motion predictions with the aid of the empirical Green's function (EGF) technique is presented. The main input parameters were identified, and their respective uncertainties were assessed by means of an international expert inquiry. The repercussion of these input uncertainties on the final ground motion estimates were investigated by means of the Latin Hypercube Sampling technique. The mean ground motion estimates (response spectra) and their standard deviations were compared with results obtained from empirical attenuation laws. The most sensitive input parameter turned out to be the seismic moment corresponding to the EGF. In general, if the source parameters are well determined, equivalent uncertainties, statistically speaking, can be expected from the EGF technique and from the application of attenuation laws. Therefore, if EGFs with well known source parameters are available, the EGF technique seems to be preferable: site effects are automatically taken into account, and physically realistic acceleration time histories can be obtained. However, further investigations on the reliability of the EGF technique should be performed, and finally, it is recalled that the EGF technique is based on the assumption of linearity. If conditions are such that this assumption cannot be maintained, the EGF technique should be combined with non-linear geotechnical methods.  相似文献   

西部开发的资源战略问题          下载免费PDF全文

宋彭生 《盐湖研究》2000,8(4):70-74

西部的资源赋存并不丰富。对全国经济发展有巨大意义的关键性资源并不多 ,由资源特性和经济发展的趋势决定了东部地区对西部地区资源的依赖降低 ,对于西部长期以资源开发为重点的发展模式所造成的多种疾患 ,以及目前国内外资源环境形势 ,提出西部注重开发技术、知识资源 ,培育特色产业 ,大力发展旅游业和建立国家资源安全战略的西部开发资源战略  相似文献   

深圳建设现代化国际性城市的条件与策略   总被引：1，自引：1，他引：0  

张志斌  仵宗卿  李静 《地域研究与开发》2000,19(1):46-49

全球化时代,城市竞争是地区竞争的突出表现,国际性城市是大城市发展的目标取向。文章依据国际性城市的内涵与条件,对深圳的地理区位、市场体制、综合实力、人口及科教水平等因素进行了系统分析与客观评价,提出了未来城市建设的国际化策略,以期对深圳“二次创业”提供参考。  相似文献