气象专业英语3课件

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,2020/9/14,#,Unit Three: Meteorological Forecasts,第三课：气象预报,New words:,Warning 警报,GMT （Greenwich Mean Time),格林威治时间,Upper-air 高空的,Sounding 探测,WWW(world weather watch) 世界天气监视网,Code 电码,GTS（global telecommunication system),全球电传通信系统,Strip 长带 belt band,NOAA(National Oceanic and Atmospheric Administration) 诺阿卫星（美国国家海洋大气管理局,）,GOES (geostationary operational environment satellite) 地球静止业务环境卫星,Multi-channel 多通道的,Assemble 组装，汇编 集合,Short-range 短期的 Long-range 长期的,nowcasting 现时预报，临近预报,Extrapolation 外推 interpolation 内插,Divergence 辐散 barotropic正压的,Prognosis 预测 smooth 平滑 filter 滤波,Geopotential 位势的,Prediction 预报 spectral 谱的 integrate 积分,Nest 嵌套 predictor 预报因子,MSL (mean sea level)平均海平面,MOS (model output statistic) 模式输出统计预报,Thunderstorm 雷暴 hurricane 飓风,Typhoon 台风,Subgrid 次网格,Substructure,n.,次级结构,sub+ 亚；次级；下级 （构词法）,Subtropic 副热带，亚热带,Unpredictable 不可预报的 predictable 可预报的,Predictability 可预报性,Frame-work 框架,Topographic 地形的 orographic,Gust 阵风 tornado （陆）龙卷,Freezing 冻结的 Doppler(radar)多谱勒雷达,Index(indices)指数 shear 切变,Downburst 下击暴流,Serve as 充当，作为,P1National Meteorological Services perform,a variety of,activities in order to provide weather forecasts. The principal ones are data collection, the preparation of basic analyses and prognostic charts of short-and long-term forecasts for the public as well as special services for aviation, shipping , agricultural and other commercial and industrial users, and the,issuance,of severe weather warnings.,1. Data sources,P2:,The data,required for forecasting and other services,are provided by worldwide standard synoptic reports at 00, 06, 12, and 18 GMT, similar observations made,hourly, particularly,in support of,national aviation requirements, upper-air soundings (at 00 and 12 GMT), satellite data and other specialized networks such as radar stations for severe weather .,Under the World Weather Watch (WWW) program, synoptic reports are made at some 4,000 land stations and by 7,000 ships.,There are about 700 stations making upper-air soundings (temperature, pressure, humidity, and, wind).,These data are transmitted in code via teletype and radio links in regional or national centers and into the high-speed Global Telecommunications System (GTS),connecting World Weather Centres in Melbourne, Moscow and Washington and eleven Regional Meteorological Centres for redistribution,.,Some 157 states and territories cooperate in this activity,under the aegis of,the World Meteorological Organization (WMO).,P3:,Meteorological information has been collected operationally by satellites of the United States and USSR since 1965 and, more recently, by the European Space Agency, India and Japan.,There are two general categories of weather satellite: polar orbiters,providing global coverage twice per 24 hours in orbital strips over the poles (such as the Unites States NOAA and TIROS series, and the USSRs Meteor),and geosynchronous satellites,(such as the Geostationary Operational Environmental Satellites (GOES) and Metosat ),giving repetitive(30-minute) coverage of almost one third of the earths surface in low middle latitudes,.,Information on the atmosphere is collected as digital data or direct readout visible and infrared images of cloud cover and sea-surface temperature, but also includes global temperature and moisture profiles,which receive radiation emitted from particular levels in the atmosphere,.,Additionally, satellites have a data collection system (DCS) that,relays,data on numerous environmental variations from ground platforms or ocean buoys,to,processing centres;,GOES can also transmit processed satellite images in facsimile and the NOAA polar orbiters have an automatic picture transmission (APT) system that is utilized at 900 stations worldwide.,2. Forecasting,P4:,Modern forecasting did not become possible until weather information could be rapidly collected, assembled and processed.,The first development came in the middle of the last century with the invention of telegraphy,which permitted immediate analysis of weather data by the drawing of synoptic charts,.,These were first displayed in Britain at the Great Exhibition of 1851.,Sequences of weather change,were correlated with,barometric pressure patterns both in space and time by such workers as Fitzroy and Abereroleby, but it was not until later that theoretival models of weather system were devisednotably the Bjerknes depression model.,P5:Forecasts are usually,referred to as,short-range, medium (or extended) range and long-range. The first two can,for present purposes,be considered together.,Short-range forecasting,P6: Forecasting procedures,developed,up to,the 1950s,were,based on,synoptic principles but, since the 1960s, practices have been revolutionized by numerical forecasting models and the adoption of “nowcasting ” techniques.,P7: During the first half of the century, short-range forecasts were based on synoptic principles, empirical rules and extrapolation of pressure changes.,P8:Since 1955 routine forecasts have been,based on,numerical models. These predict the evolution of physical processes in the atmosphere by determinations of the conservation of mass, energy and momentum. The basic principle is,that the rise or fall of surface pressure,is related to,mass convergence or divergence, respectively, in the overlying air column.,P9:,Forecast practices in the major national centres are basically similar.,The forecasts are essentially,derived from,twice-daily (00 and 12 GMT) prognoses of atmospheric circulation.,Since most techniques are now largely automated, the analyses of synoptic fields are based on the previous 12-hour forecast maps as a first guess.,Three different interpolation methods are used to obtain smoothed, grided data on temperature, moisture, wind and geopotential height for the surface at standard pressure levels (850,700,500,400,300,250,200 and 100 mb) over the globe.,The NMC currently has two basic prediction models: a special model with (6 or) 12 layers (from the boundary layer into the upper stratosphere), which is integrated for up to 10 days, and a regionally applicable nested grid model with finer horizontal resolution.,It should be noted that,typically the computer time required increases several-fold when the grid spacing is halved.,The essential forecast products are MSL pressure, temperature and wind velocity for standard pressure levels, 1000-500mb thickness, vertical motion and moisture content in the lower troposphere, and precipitation amounts.,P10:,Actual weather conditions are now commonly predicted using the Model Output Statistics(MOS) technique developed by the US National Weather Service.,Rather than,relating,weather variable,to,the predicted pressure/height patterns and,taking account of,frontal models, for example, a series of regression equations are developed for specific locations,between,the variable of interest,and,up to 10 predictors calculated by the numerical models.,Weather elements,so,predicted for numerous locations,include,daily maximum/minimum temperature, 12-hour probability of precipitation occurrence and precipitation amount, probability of frozen precipitation , thunderstorm occurrence, cloud cover and surface winds. These forecasts are distributed as facsimile maps and tables to weather offices for local use.,P11:,Errors in numerical forecast,arise from,several sources.,One of the most serious is the limited accuracy of the initial analyses,due to,data deficiencies.,The average over the oceans is sparse and only a quarter of the possible ship reports may be received within 12 hours; even over the land more than one-third of the synoptic reports may be delayed beyond 6 hours.,However, satellites-derived information and aircraft reports can help fill some gaps for the upper air.,Another limitation is imposed by the horizontal and vertical resolution of the models and the need to parameterize subgrid processes such as cumulus convection.,The small-scale nature of the turbulent motion of the atmosphere means that some weather phenomena are basically unpredictable, for example, the specific locations of shower cells in an unstable air mass. Greater precision that the “showers and bright periods” or “scattered showers” of the forecast language is impossible with present techniques. The procedure for preparing a forecasting is becoming much less subjective, although in complex weather situations the skill of the experienced forecaster still makes the technique almost,as much as,art as a science. Detailed regional or local predictions can only be made within the framework of the general forecast situation for the country and demand thorough knowledge of possible topographic or other local effects by the forecaster.,Nowcasting,P12: Severe weather is typically short-lived(2 hr ) and, due to its mesoscale character(100km), it affects local/regional areas,necessitating,site-specific forecasts. Include in this category are thunderstorms, gust fronts, tornadoes, high winds especially along coasts, over lakes and mountains, heavy snow and freezing precipitation. ,The development,of radar networks, now instruments and high-speed communication links,has,provided a means of,issuing warnings,of such phenomena., Several countries have recently developed integrated satellite and radar systems to provide information on the horizontal and vertical extend of thunderstorms, for example. Such data are supplemented by networks of automatic weather stations (including buoys) that measure wind, temperature and humidity.,In addition, for detailed boundary layer and lower troposphere data, there is now an array of vertical sounders,acoustic sounders (measuring wind speed and direction from echoes created by thermal eddies), specialized (Doppler) radar measuring winds in clear air by returns either from insects(3.5 cm wavelength radar) or from variations in the airs refractive index(10 cm wavelength radar).,Nowcasting techniques use highly automated computers and image analysis systems to integrate data from a variety of sources rapidly.,Interpretation of the data displays requires skilled personnel and/or,extensive,software to provide appropriate information. The prompt forecasting of wind shear and down-burst hazards at airports is one example of the importance of nowcasting procedures.,P13:,Overall, the greatest benefits from improved forecasting can be expected in aviation, construction and the electric power industry for forecast less than 6 hours ahead, in,transpiration, construction and manufacturing for 12-24 hour forecasts and in agriculture for 2-5 day forecasts.,In terms of,economic losses, the last category could benefit the most from more reliable and precise forecasts.,Long-range forecasting,P14: The methods discussed above are unsuitable for predicting the probable trend of the weather for periods of a month or more, because they are concerned with individual synoptic disturbances with a life cycle of about 3 to 7 days. Theoretical considerations indicate that the limit of synoptic predictability using numerical techniques is less than 15 days. Two rather different approaches will be,dealt with,later.,缩略语含义以及读法,连起来读：NOAA NASA NCAR 等,NOAA:,National Oceanic and Atmospheric Administration诺阿卫星（美国国家海洋大气管理局,）,NASA：National Aeronautic,rntk,and Space Administration(美）国家航空航天局,NCAR：National Center for Atmospheric Research(美）国家大气研究中心,NCEP :National Center for Environmental Prediction 美国国家环境预报中心,读字母发音的：WMO NMC NCC等,NMC :National Meteorological Center 国家气象中心,NCC：National Climatic Center 国家气候中心,CMA: China Meteorological Administration,CMS : China Meteorological Society,GMT: Greenwich Mean Time 格林威治标准时,LASG：State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics 大气科学和地球流体力学数值模拟国家重点实验室,经常,不断地学习,你就什么都知道。你知道得越多,你就越有,力量,Study Constantly, And You Will Know Everything. The More You Know, The More Powerful You Will,Be,学习总结,结束语,当,你尽了自己的最大努力,时,，,失败,也是伟大,的，所以不要放弃，坚持就是正确的。,When You Do Your Best, Failure Is Great, So DonT Give Up, Stick To The,End,演讲,人：,XXXXXX,时,间：,XX,年,XX,月,XX,日,