Ocean Atmosphere System
significance between ocean and atmosphere. .. Gas exchange rates between the atmosphere and the oceans depend on the concentration difference between . Their findings, based on ocean sediment core samples between million being pulled into the ocean from the atmosphere will have on climate. .. And how much, how distributed, when, where, the relationships with local. So how does something in the ocean influence the atmosphere? We already saw how hurricanes depend on the sea for energy, but there's more. The sea and.
Every three to seven years during the months of December and January, the balance between, wind, ocean currents, oceanic and atmospheric temperature and bioshpere breaks down, resulting in a severe impact on global weather. In a normal year the trade winds blow westward and push warm surface water near Australia and New Guinea. When this warm water builds up in the western Pacific-Ocean, nutrient-rich cold waters are forced to rise up from the deeper ocean just off of the west coast of South America.
This colder nutrient-rich water fosters the growth of the fish population. Warm, nutrient-poor water is not pushed westward and comes to occupy the entire tropical Pacific Ocean.
The cold water is not forced to the surface and the coastal waters of Peru and Ecuador are unusually warm.
This warmer water has a devastating impact on their fishing crops which rely on cool waters to thrive. The region also experiences an extremely higher than average amounts of rainfall. The vast tropical Pacific Ocean receives more sunlight that any other region on Earth. Much of this sunlight is stored in the ocean in the form of heat. 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. First, we study the biological factors governing DMS production and, second, we study the atmospheric processes that connect DMS with clouds.
Both require a combination of observational measurements and modelling work Ocean measurements are being made from the RV Tangaroa in the highly productive marine areas around New Zealand and show that high levels of DMS are associated with large plankton blooms. We have also measured changes in DMS in the remote Southern Ocean which were stimulated by addition of iron as a micronutrient to the ocean during an international project run by NIWA. Atmospheric measurements are carried out at the Baring Head clean air station near Wellington to determine variations in sulfate aerosol and relate these to atmospheric chemistry.
We have developed a computer model of the large number of chemical reactions involved and used this to assess the role of different oxidants. To quantify the potential climatic impact of DMS, it is important to be able to distinguish between DMS conversion to sulfate adding to existing particles and conversion that forms new particles.
We are one of very few groups able to make this distinction by using sulfur isotopes heavy and light versions of the sulfur atom. This technique relies on the fact that formation of new particles or accumulation on existing particles affects the ratio of heavy to light sulfur atoms differently.
Ocean atmosphere carbon exchange Carbon dioxide CO2 is a soluble gas which dissolves in the oceans and is taken up by marine plants phytoplankton. A natural cycle results in which CO2 is absorbed from the atmosphere in some generally cooler and more biologically active parts of the ocean and released back to the atmosphere in other generally warmer and less biologically active parts.
This natural cycle has been modified through the addition of CO2 to the atmosphere by human activities. Increasing CO2 concentrations in the atmosphere tend to increase the amount dissolved in the surface ocean. These northeast winds are called the trade winds. 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.
Energy in the Ocean and Atmosphere
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. These westerly moving air masses again become heated and start to rise creating belts of subpolar lows. Meeting of the air mass circulating down from the poles and up from the subtropical highs creates a polar front which gives rise to storms where the two air masses meet.
In general, the surface along which a cold air mass meets a warm air mass is called a front. The position of the polar fronts continually shifts slightly north and south, bringing different weather patterns across the land. In the summer months, the polar fronts shift northward, and warmer subtropical air circulates farther north. Effect of Air Circulation on Climate Atmospheric circulation is further complicated by the distribution of land and water masses on the surface of the Earth and the topography of the land.
If the Earth had no oceans and a flat land surface, the major climatic zones would all run in belts parallel to the equator. But, since the oceans are the source of moisture and the elevation of the land surface helps control where moist air will rise, climatic zones depend not only on latitude, but also on the distribution and elevation of land masses. The atmosphere picks up most of its moisture and heat from the oceans and thus weather patterns and climate are controlled by the oceans.
The oceans vary considerably in their depth.
The deepest part of the ocean is called the abyssal plain. As the seafloor starts to rise toward continental margins it is called the continental rise. The continental slope is the steep slope rising toward continual margins. The gently sloping area along the margin of a continent is called the continental shelf.
In addition, deep trenches that occur along zones where oceanic lithosphere descends back into the mantle are called oceanic trenches. These features all effect the circulation of the oceans and the ecosystems that inhabit the oceans. Coastal Zones A coastal zone is the interface between the land and water. These zones are important because a majority of the world's population inhabit such zones.
Coastal zones are continually changing because of the dynamic interaction between the oceans and the land. Waves and winds along the coast are both eroding rock and depositing sediment on a continuous basis, and rates of erosion and deposition vary considerably from day to day along such zones. The energy reaching the coast can become high during storms, and such high energies make coastal zones areas of high vulnerability to natural hazards.
Thus, an understanding of the interactions of the oceans and the land is essential in understanding the hazards associated with coastal zones. Tides, currents, and waves bring the energy to the coast, and thus we start with these three factors.
Tides Tides are due to the gravitational attraction of Moon and to a lesser extent, the Sun on the Earth. Because the Moon is closer to the Earth than the Sun, it has a larger effect and causes the Earth to bulge toward the moon.
At the same time, a bulge occurs on the opposite side of the Earth due to inertial forces this is not explained well in the book, but the explanation is beyond the scope of this course. These bulges remain stationary while Earth rotates. The tidal bulges result in a rhythmic rise and fall of ocean surface, which is not noticeable to someone on a boat at sea, but is magnified along the coasts.
Usually there are two high tides and two low tides each day, and thus a variation in sea level as the tidal bulge passes through each point on the Earth's surface. Along most coasts the range is about 2 m, but in narrow inlets tidal currents can be strong and fast and cause variations in sea level up to 16 m Because the Sun also exerts a gravitational attraction on the Earth, there are also monthly tidal cycles that are controlled by the relative position of the Sun and Moon.
The highest high tides occur when the Sun and the Moon are on the same side of the Earth new Moon or on opposite sides of the Earth full Moon. The lowest high tides occur when the Sun and the Moon are not opposed relative to the Earth quarter Moons. These highest high tides become important to coastal areas during hurricane season and you always hear dire predications of what might happen if the storm surge created by the hurricane arrives at the same time as the highest high tides.
Fluctuations in Water Level While sea level fluctuates on a daily basis because of the tides, long term changes in sea level also occur. Such sea level changes can be the result of local effects such as uplift or subsidence along a coast line.
Climate change caused by ocean, not just atmosphere, study finds
But, global changes in sea level can also occur. Such global sea level changes are called eustatic changes. Eustatic sea level changes are the result of either changing the volume of water in the oceans or changing the shape of the oceans. For example, during glacial periods much of the water evaporated from the oceans is stored on the continents as glacial ice.
This causes sea level to become lower. As the ice melts at the end of a glacial period, the water flows back into the oceans and sea level rises. Thus, the volume of ice on the continents is a major factor in controlling eustatic sea level. Global warming, for example could reduce the amount of ice stored on the continents, thus cause sea level to rise.
Since water also expands increases its volume when it is heated, global warming could also cause thermal expansion of sea water resulting in a rise in eustatic sea level. Oceanic Currents The surface of the oceans move in response to winds blowing over the surface. The winds, in effect, drag the surface of oceans creating a current of water that is usually no more than about 50 meters deep.
Thus, surface ocean currents tend to flow in patterns similar to the winds as discussed above, and are reinforced by the Coreolis Effect. But, unlike winds, the ocean currents are diverted when they encounter a continental land mass. In the middle latitudes ocean currents run generally eastward, flowing clockwise in the northern hemisphere and counterclockwise in the southern hemisphere. Such easterly flowing currents are deflected by the continents and thus flow circulates back toward the west at higher latitudes.
Because of this deflection, most of the flow of water occurs generally parallel to the coasts along the margins of continents. Only in the southern oceans, between South America, Africa, Australia, and Antarctica are these surface currents unimpeded by continents, so the flow is generally in an easterly direction around the continent of Antarctica.
Ocean Waves Waves are generated by winds that blow over the surface of oceans.
Atmosphere-Ocean Interaction | victoryawards.us
In a wave, water travels in loops. But since the surface is the area affected, the diameter of the loops decreases with depth. The diameters of loops at the surface is equal to wave height h. This depth is called wave base. In the Pacific Ocean, wavelengths up to m have been observed, thus water deeper than m will not feel passage of wave. But outer parts of continental shelves average m depth, so considerable erosion can take place out to the edge of the continental shelf with such long wavelength waves.
When waves approach shore, the water depth decreases and the wave will start feeling bottom. Furthermore, as the wave "feels the bottom", the circular loops of water motion change to elliptical shapes, as loops are deformed by the bottom.
As the wavelength L shortens, the wave height h increases. Eventually the steep front portion of wave cannot support the water as the rear part moves over, and the wave breaks. This results in turbulent water of the surf, where incoming waves meet back flowing water. Rip currents form where water is channeled back into ocean. Wave Erosion - Rigorous erosion of sea floor takes place in the surf zone, i. Waves break at depths between 1 and 1.
Thus for 6 m tall waves, rigorous erosion of sea floor can take place in up to 9 m of water.