Oceans & Atmosphere Flashcards
How do oceanic/atmospheric systems interact with other Earth systems and why is it different?
Involves rapidly moving fluids
- cryosphere; provides inputs to glaciers from precipitation, originally from evaporation of water bodies
- geosphere; wind/rain/wave erosion alter landscapes, water/air transport, temp alters by freeze-thaw
- biosphere; no water no life! Precipitation helps determine a biome, dispersion through air/water
What are the 2 main functions of the atmosphere and ocean
Atmosphere regulates temperature
Ocean circulation maintains half of the planets biology
Precipitation, ocean and atmospheric heat, wind and ocean flow all connected to the climate
How can the existence of a natural greenhouse effect be explained?
The Earth’s temp should be as cold as -18C in order to lose the same amount of energy inputed by the sun (240W/m2) BUT we obviously know this is not the case as the flowing oceans exists, it is 14C so, there must be a process that heats up and maintains the temp of Earth
What are the approximate figures for sun’s radiation per m2 of the planet, and then the total hitting our planet? What is this accounting for the Earth’s tilt and then the third of it which is reflected?
1366 W/m2 at top of atmosphere, 1.7e17W of which hits the planet
Earth is tilted so dividing it by the surface area we get 342W/m2
A third reflected, so total absorbed by Earth is 240W/m2
Describe and explain the Greenhouse Effect
Short-wave radiation from sun, passes through gases. Some absorbed by ground, some reflected/emitted back and some scattered.
Reflected long-wave radiation more likely to get absorbed by atmospheric gases - some of this is re-emitted in various directions and some comes back, warming the Earth’s surface
Main gases are CO2, H2O, CH4, O3 - H2O is most important, followed by CO2
Explain greenhouse gases as climate forcing
100% absorption of long-wave with CO2 so no more can be absorbed BUT increased concentrations can still lead to increased CO2 in the edges of ‘peaks’
There is a lot more potential for CH4 to increase as it is not saturated like CO2, it can absorb more in every wavelength band it covers
What are the percentages of the different sources of carbon emissions?
Energy supply 26% Industry 19% Forestry 17% Transport 17% Agriculture 14% Buildings 8% Waste/wastewater 3%
Explain the role of aerosols and future predictions
Particulates in the atmosphere (farming, drying then spraying soils…) e.g. burning of fossil fuels releases larger soot particles, fall out and oxidize to form solids (SO4) - solids then transported by meteoroligcal processes. Contact with water = nucleate on them, form/modify clouds…
RCP pathways predict decreased aerosol levels (seen & felt impacts!)
What is the potential impact that increased aerosols have on clouds?
- Brighter clouds = increased reflection (slowly fill up with smaller particles as opposed to larger water droplets)
- Lingering, thicker clouds = rainfall suppression as the smaller particles means it takes longer for clouds to form and rainfall to occur, thus having a localised impact on climate and also on atmospheric/oceanic circulation
In what ways is land-use changing impacting the atmospheric/oceanic systems? Remember RCPs
- Changes in land-use alter the planet’s albedo e.g. 10-25% grassland/forests, 5-10% asphalt, 10-60% oceans
- Winds and soil moisture also alter reflectivity
- NASA satellite tech; highest albedo in barren areas SO increased reflectivity as a result of increased deforestation = more radiation in atmosphere
- RCP2.6; veg/grass constant, need more intensive methods? Or more people vegan…
- RCP4.5; increase in veg/crops suddenly needed
What are some natural forcings on global climate?
- Volcanic eruptions = SO2 particulates
- Solar cycles/sun-spot activity = correlation with recent warming, but variability is tiny and not enough to account for the amount of warming that has occurred
What are the 3 main cells in atmospheric circulation? Why does air rise/sink to make these cells?
Hadley - heat&radiation at equator, hot air rises, moves N/S and cools and sinks
Ferrel - air rises again, moves further N/S, cools, sinks
Polar - again, but at the poles
Differential heating causes it, but system is more complex than just this e.g. patchy distribution, stronger over seas
What is the coriolis effect?
The force, because of the Earth’s tilt and spherical shape, that causes winds to be diverted in a specific direction depending on where they are on the planet
- Northern Hemisphere - diverted to the right
- Southern Hemisphere - diverted to the left
Partly due to conservation of angular momentum, so is strongest at the poles and weakest at the equator
Explanation in NH:
a) moving faster than Earth’s spin, E-W = wants to pull away but pulled in to centre by gravity to balance forces, diverted towards equator (as fast as)
b) slower than, W-E = wants to fall towards axis of rotation but curved surface stops this (centrifugal forces), diverted towards poles
Define specific heat capacity and heat energy capacity
Specific heat capacity - the amount of energy needed to change temp of object by 1C
Heat energy capacity - amount of energy object of interest holds (mass x shc)
Outline key details about the physical properties of the ocean - basins, mass, specific heat capacity, salt content, speed of transfer, role as a store of heat
- 4 main basins; Atlantic, Indian, Pacific, Southern
- Mass of 1.4x10topowerof21kg (greater than atmosphere’s mass of 5x10topowerof18kg)
- Very high salt content, about 35kg
- Specific heat capacity 4.2KJkg-1K-1; larger than air, rock = harder to heat oceans, more energy required and so oceans are a huge reservoir for heat
- Oceans travel slower than atmosphere
- Huge specific heat capacity = large heat content, about 90% of energy stored in system stored in oceans since 1971-2010 (IPCC, 2013)
