the hydrological cycle Flashcards
why is the hydrological cycle important
the movement of water as a liquid, gas and solid throughout the land, oceans and atmosphere is an important part of the earth’s climate system.
this continuous movement of water is known as the hydrological cycle.
explain what happens in the water cycle
as water moves through the cycle, it changes state from gas (water vapour) to liquid (rainwater, freshwater, seawater), to solids (ice, hail) and back to gas.
why is the water cycle important
this natural cycle removes some of the water impurities and constantly recycles the earths fresh water supplies
what is the driving force behind the hydrological cycle
solar energy
some of the parts of the water cycle
evaporation
condensation
precipitation
photosynthesis
runoff
what is evaporation
evaporation is the process of water changing its physical state from liquid t gas and requires an input of energy to occur.
where does most evaporation occur
most evaporation comes from the oceans as they cover 70% of the earth’s surface, with smaller amounts coming from other water bodies such as rivers and lakes
what happens when ocean water is evaporated
as ocean water evaporates it leaves behind salt, minerals and metals so only freshwater makes its way to the atmosphere.
how long does a water molecule spend in the air
about 10 days n average
what is condensation
condensation is the process of water changing its physical state from gas to liquid.
what happens in this process (condensation)
as water vapour rises, it becomes cooler and its physical state changes back into tiny liquid water droplets
depending on weather conditions, water molecules will combine with tiny particles of dust, salt and smoke in the air to form water droplets, which coalesce, grow, and develop into clouds
as water droplets coalesce, or combine with each other, clouds develop, and precipitation may also occur
what is the size of water droplets
water droplets vary in size with some being ten micros (millionths of a metre) to 1 millimetre to as large as 5 millimetres
what is coalesce
come together to form one mass or whole
what is precipitation
precipitation occurs when rain, snow or hail falls from the sky.
when enough liquid water has condensed and the atmosphere cannot support its weight, gravity ensures that the water falls from the clouds back to earth.
what form is precipitation in
water can take a liquid form (rain) or a solid form (snow/sleet/hail) depending on the air temperature.
what is virga
precipitation may also evaporate before it reaches the earth’s surface, this is known as virga
what is infiltration
as precipitation in the form of rain occurs, waterfalls to the earth where some of it soaks or infiltrates into the ground.
what is the process of infiltraction
it is then collected underground in aquifers- layers of permeable rock, sand or gravel- and this is known as ground water
where does groundwater go
groundwater will eventually seep into the rivers, creeks, lakes or other water storage bodies, thereby providing a steady flow of water even after the rain has stopped
when does runoff occur
runoff occurs when water does not soak into the ground, but rather flows across the land island.
what is that water in runoff called
is referred to as surface water and collects in creeks, streams, rivers and lakes that may flow into seas and oceans, allowing the cycle to continue
describe how runoff can occur with snow
if the temperature is cold enough the precipitation will take the form of snow on top of mountains or on the ground. this snow will eventually melt and either runoff into rivers and other water bodies, which is known as snowmelt runoff
where else can runoff go to
it can also infiltrate into the ground and collect in aquifers, as with rainwater
what is sublimination
snow and ice also evaporate directly from their frozen form to vapour this process is known as sublimation
what is photosynthesis
plant roots also absorb water in the ground. this water is then available for the plant to use in the process of photosynthesis
what are plant circulation systems powered by
by the evaporation of water from pores in the plant’s leaves- a process known as transpiration.
describe the plant circulation systems
this process equals 10% of water vapour in the atmosphere and plays a vital role in maintaining atmospheric moisture levels as clouds move away from oceans
what is evapotranspiration
the combined evaporation from water sources, the soil, and the transpiration from plants is known as evapotranspiration
what process does the hydrological cycle regulate
rainfall
humidity
cloud cover temperature
what does an undisturbed hydrological cycle create
long-term climatic patterns, to which
soil
vegetation
plants
human settlements have adapted
what would an alteration in the hydrological cycle create
any alteration in the hydrological cycle such as an increase in temperature which would amplify processes such as evapotranspiration can have significant impacts on Earth’s climate
