Carbon sink - Wikipedia
The ocean is the largest solar energy collector on Earth. by melting ice shelves, evaporating water, or directly reheating the atmosphere. . of recently revealed instrumentation problems” Geophysical Research Letters, Reducing the heat lost to the atmosphere allows the oceans to steadily warm gas emissions, but the relationship was nevertheless established. Then you have the issue of how far it penetrates and causes any heating. 0 0. Kelvin wave: It is a wave in the ocean or atmosphere that balances the. C i li f . ❑This problem can be greatly simplified by looking for solutions which η . layers can be combined to solve for the dispersive relation for the baroclinic mode of.
Rise of sea level - Warming the oceans results in expansion of water and thus increases the volume of water in the oceans. Along with melting of mountain glaciers and reduction in sea ice, this will cause sea level to rise and flood coastal zones. Changes in the hydrologic cycle - With new patterns of precipitation changes in stream flow and groundwater level will be expected. Decomposition of organic matter in soil - With increasing temperatures of the atmosphere the rate of decay of organic material in soils will be greatly accelerated.
This will result in release of CO2 and methane into the atmosphere and enhance the greenhouse effect. Breakdown of gas hydrates - This is basically solid water with gas molecules like methane locked into the crystal structure.
They occur in oceanic sediments and beneath frozen ground at the high latitudes. Warming of the oceans or warming of the soil at high lattitudes could cause melting of the gas hydrates which would release methane into the atmosphere. Since methane is a greenhouse gas, this would cause further global warming. Climate Change Because human history is so short compared to the time scales on which global climate change occurs, we do not completely understand the causes.
How Increasing Carbon Dioxide Heats The Ocean
However, we can suggest a few reasons why climates fluctuate. Long term variations in climate tens of millions of years on a single continent are likely caused by drifting continents.
If a continent drifts toward the equator, the climate will become warmer. If the continent drifts toward the poles, glaciations can occur on that continent. Short-term variations in climate are likely controlled by the amount of solar radiation reaching the Earth.
Among these are astronomical factors and atmospheric factors. Astronomical Factors - Variation in the eccentricity of the Earth's orbit around the sun has periods of aboutyears andyears. Variation in the tilt of the Earth's axis has a period of about 41, years.
Variation in the way the Earth wobbles on its axis, called precession, has a period of about 23, years. The combined effects of these astronomical variations results in periodicities similar to those observed for glacial - interglacial cycles. Atmospheric Factors- the composition of the Earth's atmosphere can be gleaned from air bubbles trapped in ice in the polar ice sheets. Studying drill core samples of such glacial ice and their contained air bubbles reveals the following: During past glaciations, the amount of CO2 and methane, both greenhouse gasses that tend to cause global warming, were lower than during interglacial episodes.Carbon dioxide ocean–atmosphere exchange
During past glaciations, the amount of dust in the atmosphere was higher than during interglacial periods, thus more heat was likely reflected from the Earth's atmosphere back into space. The problem in unraveling what this means comes from not being able to understand if low greenhouse gas concentration and high dust content in the atmosphere caused the ice ages or if these conditions were caused by the ice ages. Changes in Oceanic Circulation - small changes in ocean circulation can amplify small changes in temperature variation produced by astronomical factors.
Other factors The energy output from the sun may fluctuate. Large explosive volcanic eruptions can add significant quantities of dust to the atmosphere reflecting solar radiation and resulting in global cooling.
Circulation in the Atmosphere The troposphere undergoes circulation because of convection. Recall that convection is a mode of heat transfer. Convection in the atmosphere is mainly the result of the fact that more of the Sun's heat energy is received by parts of the Earth near the Equator than at the poles.
Thus air at the equator is heated reducing its the density. Lower density causes the air to rise. At the top of the troposphere this air spreads toward the poles. If the Earth were not rotating, this would result in a convection cell, with warm moist air rising at the equator, spreading toward the poles along the top of the troposphere, cooling as it moves poleward, then descending at the poles, as shown in the diagram above.
Once back at the surface of the Earth, the dry cold air would circulate back toward the equator to become warmed once again. Areas where warm air rises and cools are centers of low atmospheric pressure. In areas where cold air descends back to the surface, pressure is higher and these are centers of high atmospheric pressure. The Coriolis Effect - Again, the diagram above would only apply to a non-rotating Earth. Since the Earth is in fact rotating, atmospheric circulation patterns are much more complex.
The reason for this is the Coriolis Effect. The Coriolis Effect causes any body that moves on a rotating planet to turn to the right clockwise in the northern hemisphere and to the left counterclockwise in the southern hemisphere. The effect is negligible at the equator and increases both north and south toward the poles.
The Coriolis Effect occurs because the Earth rotates out from under all moving bodies like water, air, and even airplanes. Note that the Coriolis effect depends on the initial direction of motion and not on the compass direction. If you look along the initial direction of motion the mass will be deflected toward the right in the northern hemisphere and toward the left in the southern hemisphere.
Wind Systems High Pressure Centers - In zones where air descends back to the surface, the air is more dense than its surroundings and this creates a center of high atmospheric pressure. Since winds blow from areas of high pressure to areas of low pressure, winds spiral outward away from the high pressure. But, because of the Coriolis Effect, such winds, again will be deflected toward the right in the northern hemisphere and create a general clockwise rotation around the high pressure center.
In the southern hemisphere the effect is just the opposite, and winds circulate in a counterclockwise rotation about the high pressure center. Such winds circulating around a high pressure center are called anticyclonic winds.
Ocean Atmosphere System
Low Pressure Centers - In zones where air ascends, the air is less dense than its surroundings and this creates a center of low atmospheric pressure, or low pressure center. Winds blow from areas of high pressure to areas of low pressure, and so the surface winds would tend to blow toward a low pressure center.
But, because of the Coriolis Effect, these winds are deflected. In the northern hemisphere they are deflected to toward the right, and fail to arrive at the low pressure center, but instead circulate around it in a counter clockwise fashion as shown here. In the southern hemisphere the circulation around a low pressure center would be clockwise. Such winds are called cyclonic winds. Because of the Coriolis Effect, the pattern of atmospheric circulation is broken into belts as shown here.
The rising moist air at the equator creates a series of low pressure zones along the equator. Water vapor in the moist air rising at the equator condenses as it rises and cools causing clouds to form and rain to fall.
After this air has lost its moisture, it spreads to the north and south, continuing to cool, where it then descends at the mid-latitudes about 30o North and South. Descending air creates zones of high pressure, known as subtropical high pressure areas. Because of the rotating Earth, these descending zones of high pressure veer in a clockwise direction in the northern hemisphere, creating winds that circulate clockwise about the high pressure areas, and giving rise to winds, called the trade winds, that blow from the northeast back towards the equator.
In the southern hemisphere the air circulating around a high pressure center is veered toward the left, causing circulation in a counterclockwise direction, and giving rise to the southeast trade winds blowing toward the equator.
Air circulating north and south of the subtropical high pressure zones generally blows in a westerly direction in both hemispheres, giving rise to the prevailing westerly winds.
The oceans are mixed much more slowly than the atmosphere, so there are large horizontal and vertical changes in CO 2 concentration. In general, tropical waters release CO 2 to the atmosphere, whereas high-latitude oceans take up CO 2 from the atmosphere.
CO 2 is also about 10 percent higher in the deep ocean than at the surface. The two basic mechanisms that control the distribution of carbon in the oceans are referred to as the solubility pump and the biological pump. The solubility pump is driven by two principal factors. First, more than twice as much CO 2 can dissolve into cold polar waters than in the warm equatorial waters. As major ocean currents e.
Second, the high latitude zones are also places where deep waters are formed. As the waters are cooled, they become denser and sink into the ocean's interior, taking with them the CO 2 accumulated at the surface. Another process that moves CO 2 away from the surface ocean is called the biological pump. Growth of marine plants e.
Microscopic marine animals, called zooplankton, eat the phytoplankton and provide the basis for the food web for all animal life in the sea.
Because photosynthesis requires light, phytoplankton only grow in the nearsurface ocean, where sufficient light can penetrate. Although most of the CO 2 taken up by phytoplankton is recycled near the surface, a substantial fraction, perhaps 30 percent, sinks into the deeper waters before being converted back into CO 2 by marine bacteria. Scientists research the exchange of carbon dioxide between the atmosphere and ocean.
This photograph shows the Ronald H. The floating instrument in the foreground measures a number of parameters associated with the transfer of CO 2 across the air—sea interface.
The CO 2 that is recycled at depth is slowly carried large distances by currents to areas where the waters return to the surface upwelling regions. When the waters regain contact with the atmosphere, the CO 2 originally taken up by the phytoplankton is returned to the atmosphere. This exchange process helps to control atmospheric CO 2 concentrations over decadal and longer time scales.
Anthropogenic CO 2 Uptake The constant atmospheric CO 2 concentrations in the centuries prior to the Industrial Revolution suggest that the oceans released a small amount of CO 2 to the atmosphere to balance the carbon input from rivers. Today, this trend is reversed and the oceans must remove CO 2 added to the atmosphere from human activities, known as anthropogenic humanderived CO 2. In the s, the oceans removed an estimated 2. Because humans are producing CO 2 at an everincreasing rate, the average ocean removal rate increased to 2.
The uptake of anthropogenic CO 2 by the oceans is driven by the difference in gas pressure in the atmosphere and in the oceans and by the air—sea transfer velocity. Because the pCO 2 is increasing in the atmosphere, CO 2 moves into the ocean in an attempt to balance the oceanic and atmospheric gas pressures.
The mechanisms that control the speed with which the CO 2 gas can move from the atmosphere to the oceans air—sea transfer velocity are not well understood today. These results will then be used to improve gas flux estimates and modelling capabilities. Wave breaking is one of the key factors producing near-surface turbulence but also the most difficult to measure.
It also disrupts the sea surface and injects air bubbles into the water column. NIWA has developed remote sensing techniques using radar and video to measure the coverage and scale of wave breaking at sea, as well as sea state. The turbulence is measured in two ways: The relationship of the surface parameters and the resulting turbulent mixing is being established through process study experiments.
In parallel with this work, techniques are being developed to directly measure the transfer rates or fluxes of gas, heat and momentum on the atmospheric side of the sea surface.
This is more difficult over the ocean than over land since at sea the observing platform is in motion and the fluxes are very small. However, the vast expanse of the oceans and their large storage capacity makes their contribution to the global climate system important.
The challenge is to develop a system which can be applied to a range of gases and which incorporates high accuracy gas analysers. Ocean atmosphere sulfur exchange InCharlson, Lovelock, Andreae and Watson published a paper proposing what became known as the CLAW from the initial letter of each author's name hypothesis.
The hypothesis was that phytoplankton in the oceans produce a gas dimethylsulfide DMS which escapes from the ocean and undergoes a series of transformations in the atmosphere to form small sulfate particles.
These sulfate particles then act as cloud condensation nuclei CCN allowing water to condense on their surfaces creating clouds which reflect the suns radiation and cool the surface. So tiny marine organisms may be able to regulate climate through their emission of DMS. New Zealand is an excellent place to study biogenic sulfate from the ocean because there is a much smaller industrial pollution background than there is in the northern hemisphere.