Salinity and temperature determine the density of ocean water, and density influences the circulation. E-P determines surface salinity of the ocean, which helps determine the stability of the water column. Evaporation minus precipitation is usually referred to as the net flux of fresh water or the total fresh water in or out of the oceans. Inputs from rivers and melting ice can also contribute to fresh water gains. Scientists monitor the relationship between these two primary processes in the oceans. Finally, feedback between Physical and Biological Oceanography include the sea-ice and haline enivironments.Įvaporation ("E") controls the loss of fresh water and precipitation ("P") governs most of the gain of fresh water. Biological in the ocean is affected by the water cycle via the Mixed Layer Depth and Run off from land. Feedbacks between Physical Oceanography and Water Cycle are Evaporation minus Precipitation and Fresh water transports (i.e. This diagram show the relationship between Physical Oceanography, Biological Oceanography, and Water Cycle. ![]() Credit: NASA GSFC Water and Energy Cycle web site. This gigantic system, powered by energy from the sun, is a continuous exchange of moisture between the oceans, the atmosphere, and the land. The hydrologic cycle describes the pilgrimage of water as water molecules make their way from the Earth's surface to the atmosphere, and back again. Processes labeled include: precipitation, condensation, evaporation, evaportranspiration (from tree into atmosphere), radiative exchange, surface runoff, ground water and stream flow, infiltration, percolation and soil moisture. Illustration of the water cycle showing the ocean, land, mountains, and rivers returning to the ocean. On land the situation is considerably more complex, and includes the deposition of rain and snow on land water flow in runoff infiltration of water into the soil and groundwater storage of water in soil, lakes and streams, and groundwater polar and glacial ice and use of water in vegetation and human activities. The additional components of oceanic water transport are few, including the mixing of fresh water through the oceanic boundary layer, transport by ocean currents, and sea ice processes. The major physical components of the global water cycle include the evaporation from the ocean and land surfaces, the transport of water vapor by the atmosphere, precipitation onto the ocean and land surfaces, the net atmospheric transport of water from land areas to ocean, and the return flow of fresh water from the land back into the ocean. This latent heat release is an important part of the Earth’s heat balance, and it couples the planet’s energy and water cycles. Water vapor carried by the atmosphere condenses as clouds and falls as rain, mostly in the ITCZ, far from where it evaporated, Condensing water vapor releases latent heat and this drives much of the the atmospheric circulation in the tropics. This cools the surface of the ocean, and the large amount of heat absorbed the ocean partially buffers the greenhouse effect from increasing carbon dioxide and other gases. Water evaporates from the surface of the ocean, mostly in warm, cloud-free subtropical seas. Besides affecting the amount of atmospheric water vapor and hence rainfall, evaporation from the sea surface is important in the movement of heat in the climate system. The ocean holds 97% of the total water on the planet 78% of global precipitation occurs over the ocean, and it is the source of 86% of global evaporation. ![]() The ocean plays a key role in this vital cycle of water. As stated in the National Research Council's report on Research Pathways for the Next Decade (NRC, 1999): "Water is at the heart of both the causes and effects of climate change." Importance of the ocean in the water cycle The impacts of climate change and variability on the quality of human life occur primarily through changes in the water cycle. ![]() This cycling of water is intimately linked with energy exchanges among the atmosphere, ocean, and land that determine the Earth's climate and cause much of natural climate variability. Precipitation, evaporation, freezing and melting and condensation are all part of the hydrological cycle - a never-ending global process of water circulation from clouds to land, to the ocean, and back to the clouds. Water is necessary to sustaining life on Earth, and helps tie together the Earth's lands, oceans, and atmosphere into an integrated system. ![]() Earth is truly unique in its abundance of water.
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