Transcript 2. The Hydrosphere

2. The Hydrosphere
WATER
• liquid water, water
vapour & clouds
absorb energy from
warm air and the
Sun, and then
release it back.
• also reflects some of
the Sun’s energy.
The Water Cycle
 evaporates from lakes/oceans or transpiration
from plants sends water into atmosphere
 cools and condenses into clouds
 falls as precipitation
 runs off or gets into groundwater then goes
back to bodies of water
Large Bodies of Water
 water absorbs more energy than land
 lg bodies of water affect climate of a region
 take longer to warm up or cool down, so region
cooler in summer and warmer in fall
 air passing over cold water in winter picks up
vapour, condenses into snow over land, so
nearby regions have more snowfall (lake effect
snow)
Ocean Currents
• sea ice freezes at poles (fresh water)
• remaining water is salty
• dense salt water sinks to the ocean floor.
• Warmer surface water from the equator
then flows to the poles to take its place.
• This process is called the thermohaline
circulation of the oceans.
• Ocean currents around the globe slowly move
water (and the thermal energy it carries) from
the equator to the poles.
• warm currents warm air above them, over
land it warms the land and produces rain
(warm wet climate)
• why northwest Europe is warmer and wetter
than here even though it is further north (Gulf
Stream)
Thermohaline Circulation
Ice
 2% of all earth’s water is frozen, most at poles,
some in mtns
Arctic – sea ice, only a few metres thick
Antarctic & Greenland - permanent ice caps many
km thick
Glaciers – permanent ice in mountains
 together reflect back 75% of sun’s energy
 major role in climate
3. The Lithosphere
the earth’s crust
all rock, soil and minerals on earth
(including under oceans)
absorbs higher-energy UV radiation from
the Sun, converts it into thermal energy,
and emits it back as lower-energy
infrared radiation.
Land Formations, Altitude, and
Climate Zones
mtns and other landforms affect how
air moves over an area
clouds blown up mtns, lose moisture on
windward side
leeward side is dry (rain shadow effect)
as air rises it expands and cools, so air
cooler at higher altitudes
4. Living Things
• Plants and animals change the relative amounts
of gases in the atmosphere:
• photosynthesis - plants take in CO2 and
release O2
• cellular respiration - organisms take in O2 and
release CO2
• Cows and sheep produce CH4 as they digest
food.
• Termites and some bacteria produce CH4
• Some gases in the atmosphere (for
example, CO2 and CH4) absorb lowerenergy radiation emitted by Earth.
• If the amounts of CO2 and CH4 change,
it affects how much radiation the
atmosphere can absorb.