Geo 3B: Natural systems that drive Earth's climates Flashcards
Identify the spatial distribution of the world’s rainfall patterns
Average annual precipitation of the planet is estimated to be about 1050mm/year. Varies spatially from less than 10mm/month and to a max of more than 300mm/month depending on location.
Areas of lower rainfall
Deserts in the subtropical regions, located inland and along the Tropic of Cancer and Capricorn e.g. Sahara, Great Sandy desert(what an original name wow!!)
Polar areas are dry e.g. Antarctica is the driest continent in the world
Inland areas(increase distance from the sea). e.g. Perth = 850mm/year vs. Kalgoorlie(600km inland) 260mm/year.
Coastal areas/regions near cold ocean currents. Decreased evaporation e.g. Chile, Humbolt Current
Areas of higher rainfall
Areas near the equator(0-15degrees) achieve higher rainfall amounts.
Mid-latitudes(40-60degrees) experience cyclonic activity and frontal rain.
Coastal areas and regions on windward slopes of mountain ranges(Darling Escarpment).
Coastal areas and regions near warm ocean currents. Increased evaporation e.g. Queensland(Eastern Australian current).
Identify the spatial distribution of the world’s lower temperature patterns.
Nearer to the poles, beyond 37 degrees latitude is the heat deficit zone. Less insolation is received, sun at a lower angle of incidence whereby the heat is dispersed over a greater area.
Areas of higher altitude are cooler - Decrease of 6.5degrees for every 100m.
Areas of high albedo absorb less insolation, reflect more heat and are therefore cooler.
e.g. Alpine areas(snow, ice covered) have a higher albedo(40-95% reflection of insolation) - Greenland, northern Canada, Antarctica.
Identify the spatial distribution of the world’s higher temperature patterns.
Temperatures are higher nearer to the equator. 37degrees north and south latitude - heat surplus zone. Receives a greater amount of insolation, sun at a higher angle of incidence. This region receives a greater amount of insolation, sun at a higher angle of incidence.
Areas of lower albedo absorb more insolation, reflect less heart = hotter.
e.g. Forests, grasslands and sandy surfaces have a lower albedo(70-95% absorption of insolation) - Deserts(Sahara), rain forests(Amazon).
Proximity to coast - moderates temperature.
Heat island affect - air temperatures higher than surrounding rural areas.
Higher diurnal temperature ranges inland - hotter during day, cooler at night.
Definition of the Heat Budget
The balance between the input and output of energy in relation to the Earth. Energy enters the planet as short wave insolation(incoming solar radiation) and is emitted from Earth’s surface as long wave terrestrial radiation. On a global scale the amount of insolation received is equal to the amount of energy lost into space. This helps to maintain the planet’s temperature at a relatively constant level.
Outline the heat budget
The heat budget accounts for the balance between the input and output of solar energy. This equilibrium is achieved over differing time periods and through spatial variations on a global scale. The greenhouse effect is an essential component on the budget, this enables life to existing by providing a 15C global temperature average.
Short wave energy, light, is reflected and absorbed by the lithosphere and atmosphere. The Earth absorbs approximately 51% by land and water. The atmosphere and clouds absorb 19% and 30% is scattered and reflected by the atmosphere through albedo.
When light is absorbed or reflected it is converted into long wave radiation. This energy is responsible for heating the atmosphere by transferring heat absorbed by the land and water, primarily through direct heat loss(6%), conduction and convection(7%) and evaporation(23%). Some of this outgoing radiation is absorbed by greenhouse gases, such as carbon dioxide and methane(15%) and is released over long time periods. The atmosphere transfers heat back into space through clouds(26%) and air particles(38%).
Define the hydrological cycle
The continuous movement of water through Earth’s environment in the form of liquid water, water vapor, snow and ice.
Outline the hydrological cycle
Up
The amount of water in the biosphere is fixed. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air, a relatively smaller amount of moisture is added as ice and snow sublimate directly from the solid form into vapor. Rising air currents take the vapor up into the atmosphere, along with water from evapotranspiration, which is water transpired from plants and evaporated from the soil. The vapor rises into the air where cooler temperatures cause it to condense into clouds.
Down
Air currents move clouds around the globe, and cloud particles collide, grow and fall out of the sky as precipitation. Some precipitation falls as snow and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Snowpacks in warmer climates often thaw and melt in spring, and the melted water flows over land as snowmelt. Most precipitation falls back into the oceans or onto land where due to gravity, the precipitation flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, with streamflow moving water towards the oceans. Runoff, and groundwater, accumulate and are stored as freshwater in lakes.
Around and back again
Not all runoff flows into rivers, much of it soaks into the ground as infiltration. Some of the water infiltrates into the ground and replenishes aquifers(saturated subsurface rock), which store huge amounts of freshwater for long periods of time. Some infiltration stays close to land surface and emerges as freshwater springs and wetlands. Yet more groundwater is absorbed by plant roots and ends up as evapotranspiration from the leaves.
Define the carbon cycle
A biogeochemical cycle whereby carbon continues to be recycled by exchanges between sinks or reservoirs in the atmosphere, lithosphere, hydrosphere and biosphere.
Outline the carbon cycle
Lithosphere - Atmosphere
Plants and algae(autotrophs) extract carbon from the atmosphere through photosynthesis and store it as biomass. Consumers(animals) return carbon dioxide to the atmosphere and hydrosphere through respiration. Dead organisms decompose and allow carbon to enter the geosphere(surface and soil) as humus. Kucubg plants act as a carbon sink and have the ability to remove carbon from the atmosphere, sequestering it in their living tissue and soil. Forests and woodlands are examples. Fires consume biomass and organic matter produce carbon dioxide and release it into the atmosphere. The burning of fossil duels e.g. coal by humans has the same effect. Volcanic eruptions can release large volumes from the lithosphere into the atmosphere and hydrosphere(underground volcanoes).
Hydrosphere - Atmosphere
Cold ocean currents remove carbon dioxide from the atmosphere. Due to its density, this water sinks to the bottom of the oceans. Through upwelling, this carbon may return to the ocean surface within a warmer ocean current where it will be released into the atmosphere. Warm oceans release carbon dioxide back into the atmosphere.
Hydrosphere - Lithosphere
Carbon dioxide dissolves into oceans where it is used by aquatic autotrophs such as phytoplankton and corals. Aquatic animals may consume this carbon through predation whilst some carbon may fall to the bottom of the ocean. Dead marine organisms that decompose on the ocean floor become incorporated as sedimentary rocks e.g. limestone, forming a carbon sink.
Define atmospheric circulation
A system that is driven by insolation. It involves the large scale movement of air by which heat is distributed on the surface of the Earth. It generates global wind systems and high and low pressure cells. It is a major factor in regulating global temperatures.
Outline atmospheric circulation
Equatorial lows
Due to the high angle of incidence and insolation, a band of low pressure develops around the Equator. Known as the Equatorial Low, this pressure system delivers high rainfall and humidity to locations between 0 and 20 degrees latitude. The high insolation levels over this area cause air to expand and rise, this air eventually cools with altitude and descends at roughly 30 degrees north and south of the equator.
Sub Tropical Highs
The cooler air descends from the upper atmosphere, compresses against the Earth’s surface and moves outwards = creating the Sub Tropical Highs. Two major wind systems result: the South East and North East trades. These wind systems move air back to the equator, whilst Westerlies move air towards the Poles. Directional wind changes are caused by the coriolis effect. High pressure develops reducing evaporation, bringing fine and dry conditions - associated with deserts on the Tropics of Cancer and Capricorn(23.5degrees).
Sub polar Lows
At 60 degrees north and south latitude, the sub polar lows develop as a result of the collision between the Westerlies(warm winds and air masses), moving towards the Poles, and the Polar Easterlies(cool winds and air masses) moving outwards from the poles. The cool air sinks under the warm air creating fronts of heavy rain, wind and general instability.
Polar Highs
The Polar Highs result from the intense cooling of this region resulting from a low angle of incidence high albedo and dense atmosphere. Cool air descends, creates weight and moves outwards creating the Polar Easterlies. These winds take cool air back towards the Equator.
Make sure to look at interactions between cycles!
In booklet :)
