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
"Weather and Chaotic Systems" Scientists today have a very good understanding of the physical laws and mathematical equatio
"Weather and Chaotic Systems" Scientists today have a very good understanding of the physical laws and mathematical equatio
admin
2012-01-14
42
问题
"Weather and Chaotic Systems"
Scientists today have a very good understanding of the physical laws and mathematical equations that govern the behavior and motion of atoms in the air, oceans, and land. Why, then, do we have so much trouble predicting the weather? For a long time, most scientists
assumed
that the difficulty of weather prediction would go away once we had enough weather stations to collect data from around the world and sufficiently powerful computers to deal with all the data. However, we now know that weather is
fundamentally
unpredictable on time scales longer than a few weeks. To understand why, we must look at the nature of scientific prediction.
→ Suppose you want to predict the location of a car on a road 1 minute from now. You need two basic pieces of information: where the car is now, and how fast it is moving. If the car is now passing Smith Road and heading north at 1 mile per minute, it will be 1 mile north of Smith Road in 1 minute.
Now, suppose you want to predict the weather. Again, you need two basic types of information: (1) the current weather and (2) how weather changes from one moment to the next. You could attempt to predict the weather by creating a "model world." For example, you could overlay a globe of the Earth with graph paper and then specify the current temperature, pressure, cloud cover, and wind within each square. These are your starting points, or initial conditions. Next, you could input all the initial conditions into a computer, along with a set of equations (physical laws) that describe the processes that can change weather from one moment to the next.
→ Suppose the initial conditions represent the weather around the Earth at this very moment and you run your computer model to predict the weather for the next month in New York City. The model might tell you that tomorrow will be warm and sunny, with cooling during the next week and a major storm passing through a month from now. Now suppose you run the model again but make one minor change in the initial conditions—say, a small change in the wind speed somewhere over Brazil.A For tomorrow’s weather, this slightly different initial condition will not change the weather prediction for New York City.B But for next month’s weather, the two predictions may not agree at all! C
The disagreement between the two predictions arises because the laws governing weather can cause very tiny changes in initial conditions to be greatly magnified over time.D This extreme sensitivity to initial conditions is sometimes called the butterfly effect: If initial conditions change by as much as the flap of a butterfly’s wings, the resulting prediction may be very different.
→ The butterfly effect is a hallmark of chaotic systems. Simple systems are described by linear equations
in which
, for example, increasing a cause produces a proportional increase in an effect. In contrast, chaotic systems are described by nonlinear equations, which allow for subtler and more intricate interactions. For example, the economy is nonlinear because a rise in interest rates does not automatically produce a corresponding change in consumer spending. Weather is nonlinear because a change in the wind speed in one location does not automatically produce a corresponding change in another location. Many (but not all) nonlinear systems exhibit chaotic behavior.
→ Despite their name, chaotic systems are not completely random. In fact, many chaotic systems have a kind of underlying order that explains the general
features
of their behavior even while details at any particular moment remain unpredictable. In a sense, many chaotic systems are "predictably unpredictable." Our understanding of chaotic systems is increasing at a tremendous rate, but much remains to be learned about them.
According to the passage, it will be difficult to predict weather
选项
A、unless we learn more about chaotic systems
B、because we don’t have enough weather stations
C、without more powerful computers
D、until we understand the physical laws of atoms
答案
A
解析
"Our understanding of chaotic systems is increasing at a tremendous rate, but much remains to be learned about them." Choice B is not correct because it was an incorrect assumption. Choice C is not correct because it was also an incorrect assumption. Choice D is not correct because today we have a very good understanding of the physical laws of atoms.
转载请注明原文地址:https://jikaoti.com/ti/6nlYFFFM
0
托福(TOEFL)
相关试题推荐
DothefollowingstatementsagreewiththeinformationgiveninReadingPassage1?Inboxes5-13onyouranswersheet,writeT
Youshouldspendabout20minutesonQuestions1-13,whicharebasedonReadingPassage1below.Communicati
Lookatthefollowingopinionsordeeds(Questions9-13)andthelistofpeoplebelow.Matcheachopinionordeedwiththecorre
REVIEWOFRESEARCHONTHEEFFECTSOFFOODPROMOTIONTOCHILDRENThisreviewwascommissionedbytheFoodStandardsAgencytoex
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?MrSinghsayshisgenerationcouldonlydre
Thingsthatseemexcitingandfascinatingcanlaterseem______accordingtoAliandJatinder.The______mayalsohaveinforma
Theprofessorsaysthatsuperhighways______.【28】
TheTawnyOwlMost【L31】________owlspeciesinUKStronglynocturnalHabitatMainlylivesin【L32】________,butcanalsobeseeni
ThepassagefocusesoncometsprimarilyintermsoftheirItcanbeinferredfromthepassagethatthenucleusofacometism
随机试题
设计概算可分为以下三级()。
项目策划书应该在市场研究报告的_______部分中。()
28岁,孕3产1,确诊为双侧卵巢巧克力囊肿,左侧肿物8cm×8cm×9cm,右侧肿物5cm×5cm×4cm。最适宜的处理原则是下列哪项
患者,女性,30岁。半个月前因急性阑尾炎行阑尾切除术,7日前出现寒战高热伴右上钝痛,伴有恶心呕吐、乏力和食欲减退。查体:体温39.2℃,弛张热型,右上腹饱满,肝区叩痛,肋下2cm可触及肝。导致该病最可能的病原微生物是
关于宪法表现形式的说法,下列哪些选项是正确的?(卷一/2010年第62题)
某县生态环境局与水利局在联合执法过程中,发现某化工厂排污口建在防洪通道上,并对下游河水造成污染,遂联合作出责令该厂限期拆除其排污口的决定。县水利局工作人员田某向该厂送达决定书时,因遭到该厂职工围攻而受伤。该厂不服,以县水利局为被告向人民法院提起行政诉讼。下
一般均衡分析(2013年南京财经大学812西方经济学)
CiscoCatalyst6500交换机采用telnet远程管理方式进行配置,其设备管理地址是194.56.9.178/27,缺省路由是194.56.9.161,下列对交换机预先进行的配置,正确的是()。
Firstofall,successfullanguagelearnersare______.
Bread-makingPeoplemakebreadindifferentways,/butthebreadthat’smadeinBritaincontainsfiveingredients./There’
最新回复
(
0
)