首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Many of the most damaging and life-threatening types of weather--torrential rains, severe thunderstorms, and tornadoes--begin qu
Many of the most damaging and life-threatening types of weather--torrential rains, severe thunderstorms, and tornadoes--begin qu
admin
2010-01-07
60
问题
Many of the most damaging and life-threatening types of weather--torrential rains, severe thunderstorms, and tornadoes--begin quickly, strike suddenly, and dissipate rapidly, devastating small regions while leaving neighboring areas untouched. One such event, a tornado, struck the northeastern section of Edmonton, Alberta, in July 1987. Total damages from the tornado exceeded $ 250 million, the highest ever for any Canadian storm. Conventional computer models of the atmosphere have limited value in predicting short-lived local storms like the Edmonton tornado, because the available weather data are generally not detailed enough to allow computers to discern the subtle atmospheric changes that precede these storms. In most nations, for example, weather-balloon observations are taken just once every twelve hours at locations typically separated by hundreds of miles. With such limited data, conventional forecasting models do a much better job predicting general weather conditions over larger regions than they do forecasting specific local events.
Until recently, the observation--intensive approach needed for accurate, very short-range forecasts, or "Nowcasts", was not feasible. The cost of equipping and operating many thousands of conventional weather stations was prohibitively high, and the difficulties involved in rapidly collecting and processing the raw weather data from such a network were insurmountable. Fortunately, scientific and technological advances have overcome most of these problems. Radar systems, automated weather instruments, and satellites are all capable of making detailed, nearly continuous observation over large regions at a relatively low cost. Communications satellites can transmit data around the world cheaply and instantaneously, and modern computers can quickly compile and analyzing this large volume of weather information. Meteorologists and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.
Why does the author state in the first paragraph that observations are taken "just once every twelve hours"?
通过这个例子,并通过与这个例子相关的以及后续的句子可以得出答案。
选项
A、To indicate that the observations are timely.
B、To show why the observations are of limited value.
C、To compare data from balloons and computers.
D、To give an example of international cooperation.
答案
解析
B
转载请注明原文地址:https://kaotiyun.com/show/KcPd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
Forthefirsttime,scientistshaveprofiledspecificgeneticchangesduringtheagingofexperimentalanimals,adiscoverythat
Therearetwobasicwaystoseegrowth:oneasaproduct,theotherasaprocess.Peoplehavegenerallyviewedpersonalgrowtha
Amanmayusuallybeknownbythebookshereadsaswellasbythecompanyhekeeps,forthereisacompanionshipofbooksaswe
AlthoughsocialchangesintheUnitedStateswerebeingwroughtthroughoutmostofthenineteenthcentury,publicawarenessoft
Mostpeopleareright-handedandchildrenusuallyhavethesamehandednessastheirparents.Thissuggeststhatgenesareatwor
ToproducetheupheavalintheUnitedStatesthatchangedandmodernizedthedomainofhighereducationfromthemid-1860’sto
Itwasamomentmostbusinessexecutiveswouldpausetosavor:latelastyear,GermansportinggoodspioneerAdidaslearnedthat
Theaveragepersonseestensofthousandsofimagesaday—imagesontelevision,innewspapersandmagazines,andonthesidesof
HowdoesAusubelfeelaboutthescientificprogressmadeeveryday?
Itwasunfortunatethat,aftersotrouble-freeanarrival,heshouldstumbleinthedarkashewasrisingandseverelytwisth
随机试题
A公司、B公司均为石油公司,双方在D国成立了单独主体C,以共同在D国进行石油及天然气的勘探、开发和生产。A公司、B公司共同控制主体C。主体C的法律形式将主体C的资产、负债与A公司及B公司分隔开来。A公司、B公司及主体C签订协议,规定A公司与B公司按照各自在
目前临床使用最多,既方便又准确的反映肾小球滤过率的测定方法()
女,45岁。间断水肿3年,乏力3个月。查体:BP155/110mmHg,双下肢轻度凹陷性水肿。尿RBC20~30个/HP,尿蛋白2.1g/d,Hb78g/L,Cr3421μmmol/L,BUN16.1mmol/L。B超示:双肾稍萎缩。为改善乏力
在1:2000地形图上,量得某水库图上汇水面积p=1.6×104cm2,某次降水过程雨量(每小时平均降雨量)m=50mm,降水时间持续(n)为2小时30分钟,设蒸发系数k=0.5,按汇水量Q=p·m·n·k计算,本次降水汇水量为:
情报资料的内容主要包括()。
假设资本市场有效,在股利稳定增长的情况下,股票的资本利得收益率等于该股票的()。
读右图回答问题:圆圈地区洪灾严重,主要成因是()。
要把A、B、C、D四包不同的商品放到货架上,但是,A不能放在第一层,B不能放在第二层,C不能放在第三层,D不能放在第四层,那么,不同的放法共有()种。
下列关于this指针的叙述中,正确的是()。
Howdidthemanhelptheoldlady?
最新回复
(
0
)