This great reservoir continuously exchanges heat, moisture, and carbon with the atmosphere, driving our weather patterns and influencing the slow, subtle changes in our climate. The oceans influence climate by absorbing solar radiation and releasing heat needed to drive the atmospheric circulation, by releasing aerosols that influence cloud cover, by emitting most of the water that falls on land as rain, by absorbing carbon dioxide from the atmosphere and storing it for years to millions of years.
The oceans absorb much of the solar energy that reaches earth, and thanks to the high heat capacity of water, the oceans can slowly release heat over many months or years. The oceans store more heat in the uppermost 3 meters 10 feet that the entire atmosphere, the key to understanding global climate change is inextricably linked to the ocean.
Let's look at some of these processes. At the end of the last ice age, about 15, years ago, and the ice sheets melted away and climate warmed at that time.
Ice sheets began to grow, and climate cool about , years ago at the beginning of the last ice age. About 15, years ago, this process was reversed as more sunlight reached areas near the Arctic Circle, and Earth emerged from the ice age. Still recovering from the ice age, global sea level continues to rise.
The past century alone has seen global temperature increase by 0. Is this just part of the natural cycle? How much of this warming is due to the burning of fossil fuels? Is human nature affecting Mother Nature? What should we do? Our response to the challenge of global warming begins by formulating the right set of questions. The first step in addressing the issue of global warming is to recognize that the warming pattern, if it continues, will probably not be uniform.
The term "global warming" only tells part of the story; our attention should be focused on "global climate change. Some spots will warm, while others will cool; these changes, and the accompanying shifts in rainfall patterns, could relocate agricultural regions across the planet.
By studying the oceans from space, we can unlock a vast store of information about our changing environment. Climate is affected by both the biological and physical processes of the oceans. In addition, physical and biological processes affect each other creating a complex system. Both the ocean and the atmosphere transport roughly equal amounts of heat from Earth's equatorial regions - which are intensely heated by the Sun - toward the icy poles, which receive relatively little solar radiation.
The atmosphere transports heat through a complex, worldwide pattern of winds; blowing across the sea surface, these winds drive corresponding patterns of ocean currents. But the ocean currents move more slowly than the winds, and have much higher heat storage capacity. The winds drive ocean circulation transporting warm water to the poles along the sea surface. As the water flows poleward, it releases heat into the atmosphere. In the far North Atlantic, some water sinks to the ocean floor.
This water is eventually brought to the surface in many regions by mixing in the ocean, completing the oceanic conveyor belt see below. Changes in the distribution of heat within the belt are measured on time scales from tens to hundreds of years.
While variations close to the ocean surface may induce relatively short-term climate changes, long-term changes in the deep ocean may not be detected for many generations. The ocean is the thermal memory of the climate system. NASA satellite observations of the oceans of the past three decades have improved our understanding of global climate change by making global measurements needed for modeling the ocean-atmosphere climate system.
Global data sets available on time scales of days to years and, looking ahead, to decades have been and will be a vital resource for scientists and policy makers in a wide range of fields. Ocean surface topography and currents, vector winds both speed and direction , sea-surface temperature, and salinity are the critical variables for understanding the ocean-climate connection.
Scatterometers are used to measure vector winds. The SeaWinds scatterometer has provided scientists with the most detailed, continuous global view of ocean-surface winds to date, including the detailed structure of hurricanes, wide-driven circulation, and changes in the polar sea-ice masses. Scatterometer signals can penetrate through clouds and haze to measure conditions at the ocean surface, making them the only proven satellite instruments capable of measuring vector winds at sea level day and night, in nearly all weather conditions.
Bouncing radio waves off the ocean surface and timing their return with incredible accuracy, these instruments tell us the distance from the satellite to the sea surface within a few centimeters - the equivalent of sensing the thickness of a dime from a jet flying at 35, feet! Navy for more than 30 years and continues to work with the Office of Naval Research. A pioneer in the development of deep-sea submersibles and remotely operated vehicle systems, he has taken part in more than deep-sea expeditions.
In , he discovered the RMS Titanic , and has succeeded in tracking down numerous other significant shipwrecks, including the German battleship Bismarck , the lost fleet of Guadalcanal, the U.
He is known for his research on the ecology and evolution of fauna in deep-ocean hydrothermal, seamount, canyon and deep trench systems. He has conducted more than 60 scientific expeditions in the Arctic, Atlantic, Pacific, and Indian Oceans. Sunita L. Her research explores how the larvae of seafloor invertebrates such as anemones and sea stars disperse to isolated, island-like habitats, how larvae settle and colonize new sites, and how their communities change over time.
Kirstin also has ongoing projects in the Arctic and on coral reefs in Palau. Her work frequently takes her underwater using remotely operated vehicles and SCUBA and carries her to the far corners of the world. Ocean and Climate.
Abrupt Climate Change. Blue Carbon. Climate Change. Ocean Warming. Sea Level Rise. Water Cycle. Abrupt Climate Change Human activity is putting slow, inexorable pressure on the planetary system that governs Earth's climate.
Learn more. Blue Carbon Blue carbon refers to the atmospheric carbon captured and stored by the ocean in various ecosystems and organisms. Climate Change Earth naturally warms and cools over hundreds to thousands of years or more. Ocean Warming Increasing ocean heat is closely linked to increases in atmospheric greenhouse gas concentrations, making the ocean an excellent indicator of how much Earth is warming.
Water Cycle When astronomers search the galaxy for life, they look for signs of water. Dive deep into our Ocean and Climate issue Want to dive deeper into ocean-climate connections? Digital Edition. More stories about Ocean and Climate. Secrets in the dust. July 15, Science RoCS Initiative responds to need for increased ocean monitoring. The ocean science-art connection. WHOI research in five inhospitable locations. Tracking change in the Arctic Ocean. Oceans of Change.
In addition to currents, up-wellings of cold water in places where the wind blows surface water away can also affect climate. Thus San Francisco, influenced by coastal up-welling, is hardly warmer than Dublin, which is influenced by the Gulf Stream, despite being over 1, km further south. Currents involved in "deep-water formation" are particularly important for climate.
In winter, surface cooling causes water to become more dense. While fresh-water that is cooled starts to expand at temperatures below 4 C, salt-water continues to compress all the way down to its freezing point of -2 C. In areas where evaporation exceeds precipitation, the resulting rise in salinity also increases density. When the surface water becomes denser than the underlying water, "convective overturning" occurs and the dense surface water mixes downwards.
In certain places this downward mixing can occasionally extend all the way to the bottom, even in deep oceans. The dense, deep water thus formed spreads out over the whole ocean. As a result, when downward mixing takes place at high latitudes it creates a circulation pattern in which warm water from tropical and subtropical regions moves poleward, surrenders heat to the atmosphere, cools and sinks, and flows back towards the equator.
The net result is a transport of heat poleward. An apparently small change in just one aspect of the ocean's behaviour can produce major climate variations over large areas of the earth. The areas of cold-water formation are one known example of this possibly wide-spread phenomenon. Recent observations, ocean core records, and some modelling results indicate that North Atlantic deep-water formation and its associated ocean heat flow fluctuate substantially over time-scales ranging from years to millennia.
The system is vulnerable because even a relatively small decrease in surface salinity prevents water - no matter how cold it is - from sinking.
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