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
Aided by the recent ability to analyze samples of air trapped in glaciers, scientists now have a clearer idea of the relationshi
Aided by the recent ability to analyze samples of air trapped in glaciers, scientists now have a clearer idea of the relationshi
admin
2020-12-14
17
问题
Aided by the recent ability to analyze samples of air trapped in glaciers, scientists now have a clearer idea of the relationship between atmospheric composition and global temperature changing over the past 160,000 years. In particular, determination of atmospheric composition during periods of glacial expansion and retreat(cooling and warming)is possible using data from the 2,000 meter Vostok ice core drilled in Antarctica. The technique involved is similar to that used in analyzing cores of marine sediments, where the ratio of the two common isotopes of oxygen, 180 and 160, accurately reflects past temperature changes. Isotopic analysis of oxygen in the Vostok core suggests mean global temperature fluctuations of up to 10 degrees centigrade over the past 160,000 years.
Data from the Vostok core also indicate that the amount of carbon dioxide has fluctuated with temperature over the same period: the higher the temperature, the higher the concentration of carbon dioxide and the lower the temperature, the lower the concentration. Although change in carbon dioxide content closely follows change in temperature during periods of deglaciation, it apparently lags behind temperature during periods of cooling. The correlation of carbon dioxide with temperature, of course, does not establish whether changes in atmospheric composition causing the warming and cooling trends or were caused by them.
The correlation between carbon dioxide and temperature throughout the Vostok record is consistent and predictable. The absolute temperature changes, however, are from 5 to 14 times greater than would be expected on the basis of carbon dioxide’s own ability to absorb infrared radiation, or radiant heat. This reaction suggests that, quite aside from changes in heat-trapping gases, commonly known as greenhouse gases,
certain positive feedbacks
are also amplifying the temperature change. Such feedbacks might involve ice on land and sea, clouds, or water vapor, which also absorb radiant heat.
Other data from the Vostok core show that methane gas also correlates closely with temperature and carbon dioxide. The methane concentration nearly doubled, for example, between the peak of the penultimate glacial period and the following interglacial period. Within the present interglacial period it has more than doubled in just the past 300 years and is rising rapidly. Although the concentration of atmospheric methane is more than two orders of magnitude lower than that of carbon dioxide, it cannot be ignored: the radiative properties of methane make it 20 times more effective, molecule for molecule, than carbon dioxide in absorbing radiant heat. On the basis of a simulation model that climatological researchers have developed, methane appears to have been about 25 percent as important as carbon dioxide in the warming that took place during the most recent glacial retreat 8,000 to 10,000 years ago.
The primary purpose of the passage is to______.
选项
A、interpret data
B、explain research methodology
C、evaluate a conclusion
D、suggest a new technique
答案
A
解析
主旨题。根据文章第一、二、四段的首句Aided by the recent ability toanalyze samples of air trapped in glaciers,scientists now have a clearer idea…,Datafrom the Vostolk core also indicate that….Other data from the Vostok core show that…可以把握文章的主要目的是科学家通过对困在冰川中的空气样品进行分析.对大气构成与全球气温变化之间的关系进行解释说明。简而言之,就是“解释数据”,和A选项表达一致。
转载请注明原文地址:https://kaotiyun.com/show/O8P7777K
0
大学英语六级
相关试题推荐
RichChildrenandPoorOnesAreRaisedVeryDifferently[A]ThelivesofchildrenfromrichandpoorAmericanfamilieslookmore
RichChildrenandPoorOnesAreRaisedVeryDifferently[A]ThelivesofchildrenfromrichandpoorAmericanfamilieslookmore
RichChildrenandPoorOnesAreRaisedVeryDifferently[A]ThelivesofchildrenfromrichandpoorAmericanfamilieslookmore
A、Hehadbribedtheparkkeeperstokeepquiet.B、Peoplehaddifferingopinionsabouthisbehaviour.C、Theseriousconsequences
A、Theirrelationshipswiththeprofessors.B、Theirfinancialaidpackages.C、Theirlightschoolload.D、Theirrichextracurricul
A、DifferentexperiencesinEurope.B、Differentsocialandsportorganizations.C、Differentmajorsinyourcollege.D、Differentp
A、TheimportantrolethatInternetplaysinhumanlife.B、TheadvantagesoftheInternetandthecomputer.C、Theinfluenceofth
VictoriaBarzilaiopenedhermouthwidesothedoctorcouldlookathersorethroat.Not【C1】______aremarkableevent,excepttha
随机试题
甲意图杀害乙,某日趁乙不备将乙从桥上推下企图将乙淹死,不料乙却因头部碰到石头而摔死。甲的行为构成()
有关应激的心理性反应不正确的是
患者,男,50岁。因十二指肠溃疡急性穿孔2小时行毕Ⅱ式胃大部切除。术后第3天诉腹痛腹胀,肛门未排气排便。伴恶心无呕吐。查体:R18次/分,心肺(-)。全腹胀气明显,无肠型及蠕动波,上腹轻压痛,无反跳痛,无移动性浊音,肠鸣音消失。腹部平片提示膈下游离气体、小
A、心与脾的关系B、脾与肾的关系C、肺与肾的关系D、肺与脾的关系E、肺与肝的关系主要表现在血液的生成和运行()
属于永久性建筑有柱的车棚、货棚等按柱的外围水平投影计算()。
期货投资者保障基金由中国证监会、财政部指定的保障基金管理机构集中管理、统筹使用。()
马斯洛的需要层次理论中,自主权、成就感等需要是指()。
商业银行负债业务经营的核心是()。
世界上每年的粮食产量稍许超过为世界人口提供最低限度的必需量。预测不足的粮食产量将引起将来的饥饿危机是没有意义的,任何饥饿危机将由分配问题引起,而不由产量问题引起。上面的论述假设了下面哪一项?
荔波是世界自然遗产,为保护世界自然遗产,荔波的旅游开发必须控制在一定的规模内,但这有限度的旅游开发的收入不够支付保护世界自然遗产的费用。由上述断定能推出以下哪项?
最新回复
(
0
)