Water cycle TEST Flashcards
what percent of water on earth is stored as freshwater
2.5%
what percent of water on earth is stored in the oceans
96.5%
what is a closed hydrological system
one where there is a fixed amount of water on the Earth and atmosphere system
how long can water stay in the atmosphere as clouds for
10 days
how much water does the Sun evaporate every day
1 trillion tonnes
what are fluxes
how water is transferred between stores
how much ocean evaporation is there
413km^3 x 10^3 /year
how much ocean precipitation is there a year
373km^3 x 10^3 /year
what are the two processes that drive the hydrological cycle
solar energy and gravitational potential energy
how does the water budget limit the water available for consumption
through fossil water and cryosphere losses being non-renewable
what are the three types of rainfall
frontal rainfall, convectional rainfall, orographic rainfall
what is frontal rainfall
as air rises it cools and its ability to hold water vapour decreases, condensation occurs and clouds and rain form, this happens when warm and lighter air is forced to rise over cold, denser air
what is convectional rainfall
if the air continues to rise the rain will fall. When the land becomes hot, the air above it becomes warmer, expands an rises, condensation occurs and clouds develop, as it rises, the air cools and its ability to hold water vapour decreases
what is orographic rainfall
as the cloud forms, precipitation occurs, the leeward (downwind) slope receives relatively little rain, which is known as the rain shadow effect, when air is forced to rise over a barrier (such as a mountain), it cools and condenses
what is the river basin/river catchment area
the area of land drained by a river and its tributaries
what is watershed
the boundary of a drainage basin, this is usually a ridge of high land which divides and separates the water flowing different rivers
what are the human factors that affect drainage basins
deforestation, changing land use and over abstraction
between what years did the Tocantins river show increase discharge that coincided with increases rates of deforestation in the area
1960 and 1997, it showed a 25% increase in discharge
which UK cities suffered floods in 2014
Winchester and Maidenhead
what percent of London’s water comes from chalk aquifers
40%, the rest comes from the river Thames which is home to 13 million people
how much of the Amazon forest has been deforested
20% over the past 50 years
how much of the world’s rainforests does the Amazon contain
60%
in a forest how much of intercepted water is returned by evapotranspiration to the atmosphere
75%
water budget definition
a calculation of how much water there is in an area, it is important as it makes sure that people don’t die of dehydration
how long is the Nile
6,000km
how many countries does the Nile cross
9
what are three examples of impermeable rock
slat, marble and granite
what are three examples of permeable rock
sandstone, chalk and gravel
what is the definition of a flood
when a river exceeds its banks full discharge
example of snowmelt in the UK
Norfolk 2013, very mild and wet weather caused rapid thawing, which combined at the same time as heavy rain, causing local floods
example of monsoon rainfall
occurs across South and Southeast Asia between May and September, for example, in July 2016 the Philippines experienced heavy monsoon rains leading to flooding, landslides and evacuations in villages northwest of the capital Manila
storms and flash flooding example
intense, torrential storms are often associated with the UK during summer months, storms cause the capacity of the river to be overwhelmed quickly, for example in September 2016 flash flooding caused travel chaos as almost half a month’s worth of rain fell within hours in some places
what are the human causes of flooding
over farming, mismanagement of rivers and changing land use
example of mismanagement of a river causing flooding
2015, the River Greta in Keswick rose by 5.9 metres, breaching the raised riverbanks, there had been no dredging
what are the four different types of drought
meteorological, agricultural, hydrological drought, socio economic drought
what is meteorological drought
defined by shortfalls in precipitation because of short term variability within the longer term average overall, as shown in many semi-arid and arid regions such as the Sahel