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
41
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
Theeveningnewscomesonatseveno’clockand______onlythirtyminutes.
Whenshedoessomething,Mrs.Brownfeelsthatherlittlechildisalways_________.
Nowadays,especiallyinChina,everythingseemstofavorsocialintercourse,suchasgatheringsoffriends,KTV,grouptravel,d
Howmanyreallysufferasaresultoflabormarketproblems?Thisisoneofthemostcriticalyetcontentioussocialpolicyques
Distinguishedarchitecturerequirestheexpenditureoflargesumsofmoney,evenifitisbynomeanscertainthattheexpenditu
True,hehaddiplomaticimmunityastheassistantagriculturalofficerattheconsulate,butthepublicityand______ofanarrest
ASCEND:ROCKET::
TANTAMOUNT:
Thiscomposerhasnevercourtedpopularity:herruggedmodernismseemstodefyratherthanto______theaudience.
Jean-MichelBasquiat’sascendancywastruly______:hisprovocativeartsuddenlypropelledhimfromNewYorkstreetartisttoint
随机试题
抗日战争是一场全民族反抗外敌入侵的正义战争。全民族抗战以来,中国军队取得的第一次重大胜利,粉碎了日军不可战胜的神话的战役是()
A、crucialB、JuneC、excludeD、pullD选项D画线部分读[u],其他选项面线部分读[u:]。
单纯使用根治性切除手术治疗骨肉瘤,5年存活率不高,其主要原因是
对土地使用权抵押权变更的说法中正确的是()。
统计信息社会共享是指统计调查者在对所搜集到的统计资料予以保密,适当的予以公开。()
()在我国众多上市公司中或多或少地存在,交易量在各类关联交易中占首位。
某违法机构私自出售伪造、变造的人民币,下列关于其需要承担的法律责任的说法中,不正确的是()。
当遇到公民人身、财产安全受到不法侵害或者处于其他危难情形时,人民警察应当立即救助。()
一、注意事项 1.申论考试,与传统作文考试不同,是对分析驾驭材料的能力与对表达能力并重的考试。 2.作答参考时限:阅读资料40分钟,作答110分钟。 3.仔细阅读给定的资料,按照后面提出的“申论要求”依次作答。二、资料1.某记者因为
Large,multinationalcorporationsmaybethecompanieswhoseupsanddownsseizeheadlines.Buttoafargreaterextentthanmos
最新回复
(
0
)