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
Detailed knowledge of each of the jet streams of the earth’s hemispheres- its location, altitude and strength-is critical
Detailed knowledge of each of the jet streams of the earth’s hemispheres- its location, altitude and strength-is critical
admin
2011-01-17
40
问题
Detailed knowledge of each of the jet streams of the earth’s hemispheres-
its location, altitude and strength-is critical to modern-day weather
forecasting, as well as to more specific applications such as the routing of
Line aircraft. By way of definition, a jet in fluid dynamics is simply a core of fluid
(5) moving at a higher velocity than the surrounding fluid, and although
complicated to describe mathematically, the jet streams in the atmosphere are a
straightforward, natural result of the meridional (equator-to-pole) temperature
gradient in the earth’ s atmosphere. Analogous flows exist on other planets with
substantial atmospheres having similar temperature gradients.
(10) The temperature gradient derives from the differential solar heating of the
spherical surface of a planet: the surface is generally warmest at the equator
and grows progressively cooler as one moves poleward. The centrifugal effects
of the earth’s rotation, often called the Coriolis force, deflect the north-south
transport of heat from the equator to the poles into the predominantly east-west
(15) motion of the jet stream. The relative strength, or velocity, of the jet stream is
proportional to the intensity of this thermal gradient. During the winter
months, when the equator-to-pole temperature disparity is at its greatest, the
jet stream reaches its maximum velocity, while during the summer months,
when the temperature gradient between the equator and the pole is considerably
(20) less, the jet stream reaches its minimum velocity.
The jet stream does not maintain a straight, zonal flow from west to east
but rather takes on a more serpentine look, often with dramatic dips to the
south or rises to the north. There are two major reasons for these nonzonal
motions: the temperature gradient between the equator and the poles and the
(25) presence of land masses on the earth’s surface. The meridional temperature
gradient between the equator and poles that gives rise to the jet stream also
produces secondary atmospheric circulations, or eddies which, referred to by
meteorologists as baroclinic waves, have a complex interaction with the jet
stream, one that is intriguingly two-sided. The eddies modify the distribution of
(30) temperature and kinetic energy within the atmosphere, a process that has a
pronounced effect on the location and movement of the jet stream, which itself
interacts with these waves, acting not only as a transport or steering
mechanism but transferring momentum and energy back to the waves.
The presence of land masses on the earth’s otherwise watery surface also
(35) modifies the distribution of temperature, because continents heat and cool at a
dramatically slower rate than do the oceans. The topography of the land also
influences the jet stream’s location-mountain ranges and plains on large
continents, for example, significantly imbalance the distribution of atmospheric
temperature, narrowing the jet stream. And since the jet stream is a thermally
(40) driven phenomenon, the more complicated the three-dimensional temperature
structure of the earth’s atmosphere, the more "wandering" will take place in
the course of the jet stream.
According to the passage, which of the following statements about temperature gradients is true?
选项
A、These temperature gradients tend in most cases to be impossible to describe mathematically.
B、The lower the contrast between the extremes of the gradient, the lower the resulting velocity of the jet stream.
C、Jet streams are responsible for most of the north-south transfer of heat between the equator and the poles.
D、The temperature gradient tends, on a non-negligible level, to augment the effects of the earth’s rotation.
E、The gradient typically refers to differences in jet stream velocity at various longitudinal positions around the globe.
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/mCjO777K
本试题收录于:
GRE VERBAL题库GRE分类
0
GRE VERBAL
GRE
相关试题推荐
Thelittlevillagehasn’tchangedmuch______anewroadandtwomorestores.
______iswellknowntoall,Chinawillbeanadvancedandpowerfulcountryinthenearfuture.
Ecologyisthescienceofhowlivingcreaturesandplantsexisttogetheranddependoneachotherandonthelocalenvironment.
Howmanyreallysufferasaresultoflabormarketproblems?Thisisoneofthemostcriticalyetcontentioussocialpolicyques
Unlikeatypicalautomobileloan,whichrequiresafifteentotwentypercentdownpayment,thelease-loanbuyerisnotrequired
Noverysatisfactoryaccountofthemechanismthatcausedtheformationoftheoceanbasinshasyetbeengiven.Thetraditional
DIPLOMAT:TACT::
WasFelixMendelssohn(1809-1847)agreatcomposer?Onitsface,thequestionseemsabsurd.Oneofthemostgiftedprodigiesinth
随机试题
Successfulcompaniesconcentrate(much)_______onsellingtheirproductstotheirexistingcustomersthantotheirnewones.
善祛风痰的药物是
A.碘酊B.过氧乙酸C.戊二醛D.漂白粉E.乙醇干粉用于消毒排泄物的是
通常将房地产市场划分为()。
在一个容器中,反应2NO2(g)2NO(g)+O2(g),恒温条件下达到平衡后,若加入一定的Ar气体保持总压力不变,平衡将会()。
“守株待兔”错在()。
以下程序段执行后整型变量度n的值为______。n=0forI=lto20step5n=n+1nextI
有以下程序 main( ) { int i; for(i=0;i<3;i++) switch(i) { case 1: printf("%d",i); case 2: printf("%d",i); default: p
SpeakerA:CouldIgetaridewithyoutotheconcerttonight?SpeakerB:Ican’tgo,______.Ithinkshe’sleavingaround7:30
PrepareaJobInterviewThefirststeptowardsasuccessfuljobinterviewisself-assessment./Youneedtodecidewhatkind
最新回复
(
0
)