5.1 The Global Hydrological Cycle Flashcards
what system is this?
a closed system
how is this cycle a closed system?
water moves from one store to another
-includes inputs, outputs, stores and flows
how is water a renewable resource?
the processes of the cycle are constantly renewing the surface water and groundwater
cycle input
precipitation only
cycle stores
reservoirs, lakes, aquifers, glaciers and vegetation
cycle flows
rivers, evaporatation, transpiration, infiltration, percolation, throughflow and groundwater
what drives this cycle?
solar energy and gravity (GPE)
which store undergoes the most evaportation
oceans- largest surface area
what is vapour transport?
the movement of water vapour around the globe
-visible as clouds which consist of ice crystals and tiny water droplets
what % of water on the planet is freshwater?
2.5%
what percentage of freshwater is easily accessible to us?
1%
what % of water is locked up in glaciers or ice sheets?
70%
global stores
water is stored as vapour, ice, saline or freshwater
local stores
vegetation, surface, soil moisture and groundwater
non-renewable water sources
fossil water and cryosphere
-once they are used up or lost they cannot be recharged or replaced
describe the GAC model
hadley cell (0-30 degrees)
-the tropics are in a low pressure zone, high precipitation
-little variation in climatic conditions
-high temperatures, high humidity
ferrel cell (30-60 degrees)
-little rain, high pressure zone
-water deficit
-air is cold, dense and falls, dry conditions
polar cell (60-90 degrees)
-air rises and descends forming a high pressure belt at 90 degrees
-there is low rainfall - desert climate
-orographic and frontal precipitation is experienced at 60 degrees as air rises (low pressure)
residence time
the average time a molecule of water will spend in one of the stores
The ITCZ
a narrow zone of low pressure near the equator where northern and southern air masses converge
why do trade winds exist?
the earth spins meaning air moves in a certain direction around a low pressure area
-these are the westerly deflection of the descending hadley cells
describe why the UK experiences the weather it does
(position)
the UK is positioned where warm, moist air form the tropics is fed north by the ferrel cell and it meets with cool, dry air moving south in the polar cell
-polar front forms as contrasting air masses meet
-the unstable atmosphere causes unsettled weather
what is happening to the ice sheets?
the cryosphere is melting, adding more water into the sea, influencing the global circulation of water and heat transfer, driving the thermohaline circulation
