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An Argo tour of the ocean

             

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SST map
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Bathymetry (sea floor topography) from satellite altimetry and ship measurements.
Source: NOC from ETOPO2v2 data.

SST and ice map
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March sea surface temperature (SST) and sea ice cover from satellite measurements in 2006-2008. Source: NOC from Met Office OSTIA data.

SST and ice map
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June sea surface temperature (SST) and sea ice cover from satellite measurements in 2006-2008. Source: NOC from Met Office OSTIA data.

SST and ice map
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September sea surface temperature (SST) and sea ice cover derived from satellite measurements in 2006-2008. Source: NOC from Met Office OSTIA data.

SST map
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December sea surface temperature (SST) and sea ice cover from available infrared and microwave satellite measurements in 2006-2008. Source: NOC from Met Office OSTIA data.

Dynamic topography map
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Mean dynamic topography from satellites (gravimetric and altimetry) and in situ (Argo) data. Ocean currents flow along lines of equal dynamic topography, so this maps shows the features of the mean ocean circulation. Sea surface height and current speeds may vary considerably around this mean (see 'current variability'). Image source and more information: AVISO.

Current map

Wind driven surface currents. Driven by the trade winds and the mid latitude westerlies, the surface currents form large gyres in all the main ocean basins. There are five subtropical gyres; two in the Atlantic and Pacific (north and south of the equator) and one in the South Indian Ocean. Note: the arrows indicate the direction of the main currents; they do not represent current speed.

Current map
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RMS variability of sea surface height (SSH) is highest in areas where current flow is fast and variable, with numerous eddies and meanders. The five western boundary currents and the Agulhas Retroflection (south east of Africa) are such dynamic regions (orange/red on the map).

Source: P.Cipollini, NOC, from AVISO altimetry data.

July salinity map
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July sea surface salinity from climatology data based on ship, buoy and float measurements. Source: Mercator Ocean from Levitus data.

July salinity map
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January sea surface salinity from climatology data based on ship, buoy and float measurements. Source: Mercator Ocean from Levitus data.

Use the buttons below to change the map on the right to see different views of the global ocean. Click on each map to see a larger version with additional information. The float links to a new page in the 'Argo Tour'.

Sea Surface Temperature and sea ice:

Ocean circulation:

Other maps

 
 

Ocean temperatures

Ocean waters are slow to heat up and slow to cool down, as you can see by comparing sea surface temperatures (SST) and sea ice cover for March, June, September and December (above). The zone of highest SST reaches furthest into the southern hemisphere in March, and furthest into the northern hemisphere in September - almost three months after midsummer, when solar heating is highest. March and September are also the months when sea ice cover is highest/lowest.

Monthly mean temperatures for three locations at 55N with corresponding winter photos.

Temperatures at 55° North. The plot shows mean monthly temperatures for the inland and coastal locations in the photos. Can you match the sites A, B and C to locations 1, 2 and 3 on the SST map below?

Temperatures in the ocean vary a lot less than on land, ranging from about -2 °C; near the polar ice edge to nearly +40 °C in the warmest tropical seas. In contrast land temperatures span almost 150 °C, from a record low of -89.2 °C at Vostok in Antarctica to a heat record of 57.8 °C at Azizia in the Libyan desert.

The difference is due to the high heat capacity of water, which makes the ocean able to absorb or release large amounts of heat without large temperature changes.

The heat capacity of the top 3m of the ocean is equal to that of the entire atmosphere. The ocean acts as buffer to sharp changes in air temperature, so maritime climates have lower maximum and higher minimum temperatures than inland climates.

SST map with three locations, 1,2 and 3 at 55° North

Ocean temperatures

Ocean waters are slow to heat up and slow to cool down, as you can see by comparing sea surface temperatures (SST) and sea ice cover for March, June, September and December (above). The zone of highest SST reaches furthest into the southern hemisphere in March, and furthest into the northern hemisphere in September - almost three months after midsummer, when solar heating is highest. March and September are also the months when sea ice cover is highest/lowest.

Monthly mean temperatures for three locations at 55N with corresponding winter photos.

Temperatures at 55° North. The plot shows mean monthly temperatures for the inland and coastal locations in the photos. Can you match the sites A, B and C to locations 1, 2 and 3 on the SST map below?

Temperatures in the ocean vary a lot less than on land, ranging from about -2 °C; near the polar ice edge to nearly +40 °C in the warmest tropical seas. In contrast land temperatures span almost 150 °C, from a record low of -89.2 °C at Vostok in Antarctica to a heat record of 57.8 °C at Azizia in the Libyan desert.

The difference is due to the high heat capacity of water, which makes the ocean able to absorb or release large amounts of heat without large temperature changes.

The heat capacity of the top 3m of the ocean is equal to that of the entire atmosphere. The ocean acts as buffer to sharp changes in air temperature, so maritime climates have lower maximum and higher minimum temperatures than inland climates.

SST map with three locations, 1,2 and 3 at 55° North

Ocean temperatures

Ocean waters are slow to heat up and slow to cool down, as you can see by comparing sea surface temperatures (SST) and sea ice cover for March, June, September and December (above). The zone of highest SST reaches furthest into the southern hemisphere in March, and furthest into the northern hemisphere in September - almost three months after midsummer, when solar heating is highest. March and September are also the months when sea ice cover is highest/lowest.

Monthly mean temperatures for three locations at 55N with corresponding winter photos.

Temperatures at 55° North. The plot shows mean monthly temperatures for the inland and coastal locations in the photos. Can you match the sites A, B and C to locations 1, 2 and 3 on the SST map below?

Temperatures in the ocean vary a lot less than on land, ranging from about -2 °C; near the polar ice edge to nearly +40 °C in the warmest tropical seas. In contrast land temperatures span almost 150 °C, from a record low of -89.2 °C at Vostok in Antarctica to a heat record of 57.8 °C at Azizia in the Libyan desert.

The difference is due to the high heat capacity of water, which makes the ocean able to absorb or release large amounts of heat without large temperature changes.

The heat capacity of the top 3m of the ocean is equal to that of the entire atmosphere. The ocean acts as buffer to sharp changes in air temperature, so maritime climates have lower maximum and higher minimum temperatures than inland climates.

SST map with three locations, 1,2 and 3 at 55° North

Ocean temperatures

Ocean waters are slow to heat up and slow to cool down, as you can see by comparing sea surface temperatures (SST) and sea ice cover for March, June, September and December (above). The zone of highest SST reaches furthest into the southern hemisphere in March, and furthest into the northern hemisphere in September - almost three months after midsummer, when solar heating is highest. March and September are also the months when sea ice cover is highest/lowest.

Monthly mean temperatures for three locations at 55N with corresponding winter photos.

Temperatures at 55° North. The plot shows mean monthly temperatures for the inland and coastal locations in the photos. Can you match the sites A, B and C to locations 1, 2 and 3 on the SST map below?

Temperatures in the ocean vary a lot less than on land, ranging from about -2 °C; near the polar ice edge to nearly +40 °C in the warmest tropical seas. In contrast land temperatures span almost 150 °C, from a record low of -89.2 °C at Vostok in Antarctica to a heat record of 57.8 °C at Azizia in the Libyan desert.

The difference is due to the high heat capacity of water, which makes the ocean able to absorb or release large amounts of heat without large temperature changes.

The heat capacity of the top 3m of the ocean is equal to that of the entire atmosphere. The ocean acts as buffer to sharp changes in air temperature, so maritime climates have lower maximum and higher minimum temperatures than inland climates.

SST map with three locations, 1,2 and 3 at 55° North

Information about dynamic topography and ocean currents coming soon.

Ocean currents

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Summer in Repparfjord, Arctic Norway
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Summer in Rothera, Antarctic Peninsula.

Ocean waters are always on the move. The flow of the currents influences climate and living conditions for plants and animals - even on land.

Ocean currents

  • cool the tropics and warm high latitudes;
  • influence rainfall patterns around the world, sometimes creating droughts or floods;
  • create fertile fishing grounds in one area, ocean 'deserts' in another;
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Ship routing
  • transport pollutants released by one country to the beaches of a neighbour;
  • affect the operations of shipping and other offshore industries.

Measuring, understanding and predicting the flow of ocean currents is important, even for those of us who live far away from the sea. Argo floats are part of a global ocean observing system that makes this possible.

Information about current variability coming soon.

Information about ocean salinity coming soon.

Information about ocean salinity coming soon.

Ocean bathymetry

The Ocean contains 97% of the world's water and covers about 71% of the Earth's surface. More than half this area is deeper than 3km. The abyssal plains of the main oceans reach 4-5 km or more, and the deepest of the ocean trenches is over 11 km deep. The ocean is a three-dimensional world, with ridges and rifts, plains and plateaus. Bathymetry charts this under-sea landscape.

Drawing of Challenger
HMS Challenger 1872-1876
GEOSAT artist impression
Bathymetry from GEOSAT

Bathymetry is the measurement of the depth of bodies of water. Early bathymetry used a heavy rope or cable lowered over a ship's side. This was time consuming, so most of the deep ocean remained uncharted until the use of echo sounders became common on survey ships during the 1930s. Today bathymetric data typically comes from sonars, which send a sound signal to the bottom and measures the distance from the time it takes for the sound to return. Satellites are also used to map bathymetry by detecting the subtle variations in sea level caused by the gravitational pull of undersea mountains, ridges, and plateaus.

Accurate bathymetric maps are essential for safe navigation and operation of offshore industries. Bathymetry is also important for understanding and predicting the flow of ocean currents. The continents and partial barriers created by ridges, sea mounts, plateaus and islands shape and control the flow of water through the deep ocean.

Link to the main Euro-Argo project website.