Catchment Hydrology - The Drainage Basin As A System Flashcards
Name the four major spheres of the ‘Earth system’
Lithosphere - Solid part of Earth, interior of Earth and thin layer of soil
Biosphere - Collection of all living things on Earth (plants, animals, bacteria etc.)
Hydrosphere - Earth’s bodies of water (frozen water is called the cryosphere)
Atmosphere - Blanket of gas that surrounds the Earth
What are the estimated contributors to sea level rise?
Ocean thermal expansion - 1.6mm per year
Glaciers and icecaps - 0.8mm per year
Antarctic ice sheet - 0.2mm per year
Greenland ice sheet - 0.2mm per year
Why is Lake available so important as a water source?
Holds 20% of all the world’s freshwater
If all rivers in the world could be diverted to drain Baikal at once, it would take over a year to empty
Could provide Earth’s population with drinking water for 50 years
What has happened to historic sea levels?
60,000 km of cracks in Greenland
350 million years ago CO² were 400ppm (394ppm today)
10-15% of current population would be under water
During Pliocene, sea levels rose 60m over 400 years (1m every 20 years)
What are the implications for the future?
Greenland ice sheet holds enough water to raise sea levels by 7m, Antarctic by 60m
90% chance seas levels will be 20m higher in 2100
2012, seas levels highest for 120,000 years
US Coast: 29% of population, 5 of 10 largest cities, generates 45% of GDP ($6.6 trillion)
Why is the cryosphere important?
Meltwater supplies 75% if water used by West America
Greenland contains 10% of world’s glacial ice
Permafrost covers 20% of northern hemisphere
Oceans currents start when salt water sinks, drives oceans currents and climate
What is happening in the polar regions today?
New era of river capture - one area flooded the other drought
South East Peninsula of Antarctica releasing 600km³ of water per year
More regular and more intense storms
What is the transfer of matter?
When matter moves from one sphere to another, a process driven by energy caused it to happen e.g. Water moving from river to air by evaporation
Processes are driven by energy so need to be in balance e.g. Decay slows down as temperatures drop and decomposers slow
What are the three cycles that Milankovitch discovered that affect the Earth’s climate?
Eccentricity
Axial tilt
Precession
What is eccentricity?
Earth’s orbit is not fixed
Changing from circular to elliptical, 91,000 year cycle
Causes cooling during circular orbit and warming during elliptical orbit
What is axial tilt?
- Inclination of the Earth’s axis in relation to its plane of orbit around the Sun
- Changes occur every 41,000 years from 21.5 to 24.5 degrees
- Causes severity of season changes
What is precession?
- Earth’s slow wobble as it spins on axis
- Changes every 23,000 years
- Currently, causes Northern Hemisphere to experience winter when the Earth is furthest from the Sun and summer when the Earth is closest to the Sun
What changes occur in lake stores?
Western US, drought and growing population led to decrease is regions biggest reservoir
Lakes in other parts of world are growing. E.g. In East Asia warmer temps are melting glaciers and lakes have formed from runoff
Summarise the key recent changes in the cryosphere
Experts unable to get to precious ice sheets in Antarctica. Grounding lines moving away from sea, reached levels of 22m
Ice sheets shrinking, less water in cryosphere
Why is the reduction in the cryosphere happening?
Warmer oceans due to global warming
Increase in water under ice sheet, resulting in increase in erosion
