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
"The Hydrologic Cycle" →The hydrologic cycle is the transfer of water from the oceans to the atmosphere to the land and back
"The Hydrologic Cycle" →The hydrologic cycle is the transfer of water from the oceans to the atmosphere to the land and back
admin
2012-01-14
39
问题
"The Hydrologic Cycle"
→The hydrologic cycle is the transfer of water from the oceans to the atmosphere to the land and back to the oceans. The processes involved include evaporation of water from the oceans; precipitation on land; evaporation from land; and runoff from streams, rivers, and subsurface groundwater.
The hydrologic cycle is driven by solar energy, which evaporates water from oceans, freshwater bodies, soils, and vegetation.
Of the total 1.3 billion km water on Earth, about 97% is in oceans, and about 2% is in glaciers and ice caps. The rest is in freshwater on land and in the atmosphere. Although it represents only a small fraction of the water on Earth, the water on land is important in moving chemicals, sculpturing landscape, weathering rocks, transporting sediments, and providing our water resources. The water in the atmosphere-only 0.001% of the total on Earth-cycles quickly to produce rain and runoff for our water resources.
Especially important from an environmental perspective is that rates of transfer on land are small relative to what’s happening in the ocean. For example, most of the water that evaporates from the ocean falls again as precipitation into the ocean. On land, most of the water that falls as precipitation comes from evaporation of water from land. This means that regional land-use changes, such as the building of large dams and reservoirs, can change the amount of water evaporated into the atmosphere and change the location and amount of precipitation on land-water we depend on to raise our crops and supply water for our urban environments. Furthermore, as we pave over large areas of land in cities, storm water runs off quicker and in greater volume, thereby increasing flood hazards. Bringing water into semi-arid cities by pumping groundwater or transporting water from distant mountains through aqueducts may increase evaporation, thereby increasing humidity and precipitation in a region.
Approximately 60% of water that falls by precipitation on land each year evaporates to the atmosphere. A smaller
component
(about 40%) returns to the ocean surface and subsurface runoff. A This small annual transfer of water supplies resources for rivers and urban and agricultural lands. B Unfortunately, distribution of water on land is far from uniform. C As human population increases, water shortages will become more frequent in arid and semi-arid regions, where water is naturally nonabundant. D
→At the regional and local level, the
fundamental
hydrological unit of the landscape is the drainage basin (also called a watershed or catchment). A drainage basin is the area that contributes surface runoff to a particular stream or river. The term drainage basin is usually used in evaluating the hydrology of an area, such as the stream flow or runoff from hill slopes. Drainage basins vary greatly in size, from less than a hectare (2.5 acres) to millions of square kilometers. A drainage basin is usually named for its main stream or river, such as the Mississippi River drainage basin.
→The main process in the cycle is the global transfer of water from the atmosphere to the land and oceans and back to the atmosphere. Together, the oceans, ice caps and glaciers account for more than 99% of the total water, and both are generally unsuitable for human use because of salinity (seawater) and location (ice caps and glaciers). Only about 0.001% of the total water on Earth is in the atmosphere at any one time. However, this relatively small amount of water in the global water cycle, with an average atmospheric residence time of only about 9 days, produces all our freshwater resources through the process of precipitation.
→ On a global scale, then, total water abundance is not the problem; the problem is water’s availability in the right place at the right time in the right form. Water can be found in either liquid, solid, or gaseous form at a number of locations at or near Earth’s surface. Depending on the specific location, the residence time may vary from a few days to many thousands of years. However, as mentioned, more than 99% of Earth’s water in its natural state is unavailable or unsuitable for beneficial human use. Thus, the amount of water for which all the people, plants, and animals on Earth compete is much less than 1% of the total.
As the world’s population and industrial production of goods increase, the use of water will also accelerate. The world per capita use of water in 1975 was about 185,000 gal/yr. And the total human use of water was about 1015 gal/yr. Today, world use of water is about 6,000, which is a
significant
fraction of the naturally available freshwater.
How do man-made water resources such as reservoirs and lakes affect the water cycle?
选项
A、They increase the danger of flooding in the areas surrounding them.
B、They cause changes in the patterns of rainfall in the immediate area.
C、They provide water sources for agricultural purposes in dry areas.
D、They improve the natural flow of water into the oceans.
答案
B
解析
"... the building of large dams and reservoirs, can change the amount of water evaporated into the atmosphere and change the location and amount of precipitation on land." Choice A is not correct because pavement increases flooding. Choice C is not correct because it refers to the purpose of the man-made water sources, not to their effect on the water cycle. Choice D is not correct because aqueducts transport water from the mountains, but they do not improve the flow into the oceans.
转载请注明原文地址:https://kaotiyun.com/show/yUyO777K
0
托福(TOEFL)
相关试题推荐
Harborsare(protected)areas(ofwater)thatcanbe(usedthe)transferofpassengersandcargo(between)shipsshore.
Whatisthemainideaofthepassage?Thepassagesuggeststhatoxygenremainedintheatmospherebecause______.
Tunas(migratelong)distancesoveralltheworld’s(oceans)andoccupy(tropical),temperate,andeven(some)thecoolerwaters
NarratorListentoapartofalectureinanecologyclass.Whatcanbeinferredaboutplantsinthehydrologiccycle?
NarratorListentoapartofalectureinanecologyclass.ThefollowingarepartsoftheHydrologiccycleEXCEPT______.
"TheHydrologicCycle"→Thehydrologiccycleisthetransferofwaterfromtheoceanstotheatmospheretothelandandback
随机试题
下列不属于Access2010算术运算符的是()
肠套叠或肠扭转致肠出血梗死的原因是
关于妊娠合并病毒性肝炎,下述错误的是
胯腹痈初起可选用的外用药物是
某省甲市A区法院受理一起保管合同纠纷案件。根据被告管辖权异议,A区法院将案件移送该省乙市B区法院审理。乙市B区法院经审查认为,A区法院移送错误,本案应归甲市A区法院管辖,发生争议。关于乙市B区法院的做法,下列哪一选项是正确的?(2010年试卷三第39题)
房地产经纪人员职业道德的内涵主要涉及职业良心和()方面。
下列关于内部收益率的表述中,不正确的是()。
()是洞室断面开挖的主要炮眼。
甲公司是一家煤矿开采企业,依据开采的原煤产量按月提取安全生产费,提取标准为每吨15元,假定每月原煤产量为10万吨。2010年5月26日,经有关部门批准,该企业购入一批需要安装的用于改造和完善矿井运输的安全防护设备,价款为100万元,增值税的进项税额为17万
FromthetearsinNedra’seyeswecandeducethatsomethingsad______.
最新回复
(
0
)