Ocean temperatures and sea level

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Recent sea surface temperature 

Sea surface temperatures 9 December 2014 (degrees C). White areas represents land areas. Map source: NCEP. Technical notes on the production of the map are available here. Please use this link if you want to see the original figure or want to check for a more recent update than shown above.

Sea surface temperature anomalies 9 December 2014 (degrees C). This map shows the current anomaly (deviation from normal) of the surface temperature of Earth's oceans. White represents land areas. White shows the extent of sea ice. Map source: NCEP. Technical notes on the production of the map are available here. Please use this link if you want to see the original figure or want to check for a more recent update than shown above.

 

Arctic sea surface temperatures 9 December 2014 (degrees C). White areas represents land areas. Map source: NCEP. Technical notes on the production of the map are available here. Please use this link if you want to see the original figure or want to check for a more recent update than shown above.

Arctic sea surface temperature anomalies 9 December 2014 (degrees C). This map shows the current anomaly (deviation from normal) of the sea surface temperature within the region shown. White areas represents land areas. Map source: NCEP. Technical notes on the production of the map are available here. Please use this link if you want to see the original figure or want to check for a more recent update than shown above.

 

 

Sea surface temperature variations since January 1983 across the Indian and Pacific Ocean, between 3.5 degrees north and south of Equator. The west-east transect shown covers the area between the east coast of Africa and the west coast of South America. Diagram source: NOAA/ESRL. Please use this link if you want to see the original figure or want to check for a more recent update than shown above. Last day shown: 11 November 2014.

 

 

Arctic and North Atlantic sea surface temperature 10 December 2014 (degrees C), according to the Centre for Ocean and Ice at the Danish Meteorological Institute (DMI). This map shows the current sea surface temperature (SST) to the left, and the anomaly (deviation from the average of the reference period) to the right. White areas represents the current sea ice cover. Grey areas are land areas. Reference period: 1961-1990. Please use this link if you want to see the original figures or want to check for more recent updates than shown above.

 

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Sea surface temperatures

Global monthly average lower troposphere temperature above oceans since 1979, according to University of Alabama at Huntsville, USA. This graph uses data obtained by the National Oceanographic and Atmospheric Administration (NOAA) TIROS-N satellite, interpreted by Dr. Roy Spencer and Dr. John Christy, both at Global Hydrology and Climate Center, University of Alabama at Huntsville, USA. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. Reference period 1981-2010. Last month shown: November 2014. Last diagram update: 4 December 2014.

  • Click here to download the entire series of UAH MSU global monthly lower troposphere temperatures since December 1978.

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Global monthly average sea surface temperature (SST) since 1979 according to University of East Anglia's Climatic Research Unit (CRU), UK. The data series (HadSST2) are described by Ranier et al. (2006). Base period: 1961-1990. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. Last month shown: November 2014. Last diagram update: 19 December 2014.

  • Click here or here to download the entire HadSST3 temperature series since 1850.

  • Click here or here to download the entire HadSST2 temperature series since 1850.

  • Click here to read a description of the data file format.

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Global monthly average sea surface temperature (SST) since 1979 according to the National Climatic Data Center (NCDC), USA. Base period: 1901-2000. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. Last month shown: November 2014. Last diagram update: 19 December 2014.

  • Click here to download the entire NCDC SST temperature series since 1880.

  • Click here to read a description of the data types used for producing the NCDC SST data series.

  • Click here to read about data smoothing.

 

 

Coverage map for sea surface temperatures shown in the four diagrams below.

 

 

Global monthly sea surface temperature (SST) in the Tropics (10oN-10oS, 0-360o) since 1979 according to the National Oceanographic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC). The geographical sampling area is shown in map above as 'Tropics'. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. The warming period directly influenced by the 1998 El Niņo is clearly visible. The data series goes back to January 1950. Here it is shown since 1979, to enable easy comparison with air the global temperature estimates shown above. Reference period: 1981-2010. Last month shown: October 2014. Last diagram update: 7 November 2014.

  • Click here to download the entire series of NOAA CPC monthly sea surface temperatures since January 1950.

  • Click here to read about data smoothing.

 

Global monthly sea surface temperature (SST) in the North Atlantic (5o-20oN, 30-60oW) since 1979 according to the National Oceanographic and Atmospheric Administration (NOAA) Climate Prediction Center. The geographical sampling area is shown in map above as 'N.Atl'. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. The data series goes back to January 1950. Here it is shown since 1979, to enable easy comparison with air the global temperature estimates shown above. Reference period: 1981-2010. Last month shown: October 2014. Last diagram update: 7 November 2014.

  • Click here to download the entire series of NOAA CPC monthly sea surface temperatures since January 1950.

  • Click here to read about data smoothing.

 

 

Global monthly sea surface temperature (SST) in the South Atlantic (0-20oS, 30oW-10oE) since 1979 according to the National Oceanographic and Atmospheric Administration (NOAA) Climate Prediction Center. The geographical sampling area is shown in map above as 'S.Atl'. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. The data series goes back to January 1950. Here it is shown since 1979, to enable easy comparison with air the global temperature estimates shown above. Reference period: 1981-2010. Last month shown: October 2014. Last diagram update: 7 November 2014.

  • Click here to download the entire series of NOAA CPC monthly sea surface temperatures since January 1950.

  • Click here to read about data smoothing.

 

 

Global monthly sea surface temperature (SST) in the Niņo 3.4 region (5oN-5oS, 17oW-120oW) of the central Pacific Ocean since 1979 according to the National Oceanographic and Atmospheric Administration (NOAA) Climate Prediction Center. The geographical sampling area is shown in map above as 'Niņo 3.4'. The thick line is the simple running 37 month average, nearly corresponding to a running 3 yr average. The data series goes back to January 1950. Here it is shown since 1979, to enable easy comparison with air the global temperature estimates shown above. Last month shown: October 2014. Last diagram update: 7 November 2014.

  • Click here to download the entire series of NOAA CPC monthly sea surface temperatures since January 1950.

  • Click here to read about data smoothing.

 

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Tropical sea surface temperature and global surface air temperature

Global monthly sea surface temperature (red) in the Tropics (10oN-10oS, 0-360o) since January 1950 according to the National Oceanographic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC). The geographical sampling area is shown in map above as 'Tropics'. Global monthly average surface air temperature (blue) since January 1950 according to Hadley CRUT, a cooperative effort between the Hadley Centre for Climate Prediction and Research and the University of East Anglia's Climatic Research Unit (CRU), UK. Base period for the NOAA series is 1971-2000, while the HadCRUT3 series uses 1961-1990 as base period. Last month shown: September 2014. Last diagram update: 28 October 2014.

 

The relation the global surface air temperature (HadCRUT3) and the tropical sea surface temperature (NOAA) shown in the diagram above is interesting. The offset between the two data series is due to the different base periods adopted, but in general the two data series tend to follow each other, without the general offset growing or decreasing since 1950.

Typically, 1-5 yr variations in the sea surface temperature have a larger amplitude than the corresponding variations in global surface air temperature. In addition, quite often a change in sea surface temperature appears to be initiated 1-3 months before the corresponding change in surface air temperature. In such cases, the temperature in the lower atmosphere appears to be controlled by change in sea surface temperatures, and not the other way around. Oceanographic processes such as, e.g., upwelling of warm or cold water masses might one obvious explanation. Another explanation might be variations in the amount of direct short wave solar radiation reaching the ocean surface. Whatever the control, the above diagram suggests that the tropical oceans are important for understanding global surface air temperature changes.

The apparent significance of the tropical oceans between 10oN and 10oS for the global surface air temperature is not entirely surprising. About 80% of the planet surface is covered by oceans between 10oN and 10oS, so the surface area covered by oceans is huge in this sector of the planet. Presumably the explanation for the significance of these tropical oceans is therefore relatively straight forward: The huge ocean surface in the Tropics is nearly perpendicular to the incoming direct solar radiation at daytime. Little of the direct short wave radiation reaching the ocean is therefore reflected, and the amount of absorbed solar radiation is essentially controlled by the tropical cloud cover. Variations in the tropical cloud cover may therefore be expected to represent an important control on the global surface air temperature, along with oceanographic phenomena (upwelling, etc.) within the tropical regions. 

 

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Ocean 0-2000m depth temperature summary

Diagram showing average 0-2000m depth ocean temperatures in selected latitudinal bands, using Argo-data. The thin line shows monthly values and the thick line shows the running 13-month average. Source: Global Marine Argo Atlas. Latest month shown: September 2014. Last diagram update: 4 December 2014.

  • Acknowledment and additional information: Roemmich, D. and J. Gilson, 2009. The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo Program. Progress in Oceanography, 82, 81-100.

 

 

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Oceanic average temperature 0-100 m depth

World Oceans vertical average temperature 0-100 m depth since 1955. The thin line indicate 3-month values, and the thick line represents the simple running 39-month (c. 3 year) average. Data source: NOAA National Oceanographic Data Center (NODC). Base period 1955-2010. Last period shown: July-September 2014. Last diagram update 19 December 2014.

  • Click here to download the entire series of three-monthly oceanic temperature anomalies since January-March 1955.

  • Click here to read about data smoothing.

 

 

Pacific Ocean vertical average temperature 0-100 m depth since 1955. The thin line indicate 3-month values, and the thick line represents the simple running 39- month (c. 3 year) average. Data source: NOAA National Oceanographic Data Center (NODC). Base period 1955-2010.  Last period shown: July-September 2014. Last diagram update 19 December 2014.

  • Click here to download the entire series of three-monthly oceanic temperature anomalies since January-March 1955.

  • Click here to read about data smoothing.

 

 

Atlantic Ocean vertical average temperature 0-100 m depth since 1955. The thin line indicate 3-month values, and the thick line represents the simple running 39- month (c. 3 year) average. Data source: NOAA National Oceanographic Data Center (NODC). Base period 1955-2010.  Last period shown: July-September 2014. Last diagram update 19 December 2014.

  • Click here to download the entire series of three-monthly oceanic temperature anomalies since January-March 1955.

  • Click here to read about data smoothing.

 

 

 

Indian Ocean vertical average temperature 0-100 m depth since 1955. The thin line indicate 3-month values, and the thick line represents the simple running 39- month (c. 3 year) average. Data source: NOAA National Oceanographic Data Center (NODC). Base period 1955-2010.  Last period shown: July-September 2014. Last diagram update 19 December 2014.

  • Click here to download the entire series of three-monthly oceanic temperature anomalies since January-March 1955.

  • Click here to read about data smoothing.

 

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Global oceanic temperature anomaly 0-700 m depth

 

World Oceans vertical average temperature 0-700 m depth since 1979. The thin line indicate 3-month values, and the thick line represents the simple running 39-month (c. 3 year) average. Data source: NOAA National Oceanographic Data Center (NODC). Base period 1955-2010. Last period shown: July-September 2014. Last diagram update 19 December 2014.

  • Click here to download the entire series of three-monthly oceanic temperature anomalies since January-March 1955.

  • Click here to read about data smoothing.

 

World Oceans vertical average temperature 0-700 m depth since 1955. The thin line indicate 3-month values, and the thick line represents the simple running 39-month (c. 3 year) average. Data source: NOAA National Oceanographic Data Center (NODC). Base period 1955-2010. Last period shown: July-September 2014. Last diagram update 19 December 2014.

  • Click here to download the entire series of three- monthly oceanic temperature anomalies since January-March 1955.

  • Click here to read about data smoothing.

 

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North Atlantic (60-0W, 30-65N) heat content 0-700 m depth

Map showing the North Atlantic area within 60-0W and 30-65N, for which the heat content within the uppermost 700 m is shown in the two diagrams below.

 

 

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the North Atlantic (60-0W, 30-65N) ocean since January 1979. The thin line indicate monthly values, and the thick line represents the simple running 37 month (c. 3 year) average. The starting month (January 1979) is chosen to enable easy comparison with global air temperature estimates within the satellite period. Data source: National Oceanographic Data Center (NODC). Last period shown: April-June 2014. Last diagram update 23 September 2014.

 

 

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the North Atlantic (60-0W, 30-65N) ocean since January 1955. The thin line indicate monthly values, and the thick line represents the simple running 37 month (c. 3 year) average. Data source: National Oceanographic Data Center (NODC). Last period shown: April-June 2014. Last diagram update 23 September 2014.

 

 

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North Atlantic 59 N transect to 1900 m depth

Depth-temperature diagram along 59 N across the North Atlantic, extending from northern Labrador in the west to northern Scotland in the east, using Argo-data. The uppermost panel shows the temperature, and the lower diagram shows the temperature anomaly, using the monthly average temperature 2004-2013 as reference. Source: Global Marine Argo Atlas. Latest month shown: September 2014. Last diagram update: 4 December 2014.

  • Acknowledment and additional information: Roemmich, D. and J. Gilson, 2009. The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo Program. Progress in Oceanography, 82, 81-100.

  • Upper panel in the above diagrams shows the main North Atlantic Current in this transect to be located between 30W and 0W, at 0-800 m depth. See diagram below to se a time series since January 2004 for this part of the transect.

 

 

Average temperature along 59 N, 30-0W, 0-800m depth, corresponding to the main part of the North Atlantic Current, using Argo-data. Source: Global Marine Argo Atlas. Latest month shown: September 2014. Last diagram update: 4 December 2014.

  • Acknowledment and additional information: Roemmich, D. and J. Gilson, 2009. The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo Program. Progress in Oceanography, 82, 81-100

 

 

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Arctic gateway seas (20W-40E. 70-80N) heat content 0-700 m depth

Map showing the Arctic Gateway Seas within 20W-40E and 70-80N, for which the heat content within the uppermost 700 m is shown in the three diagrams below.

 

 

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the East Greenland Sea (20-0W, 70-80N) since January 1955. The thin line indicate monthly values, and the thick line represents the simple running 37 month (c. 3 year) average. These data may be compared with Arctic sea ice variations. Data source: National Oceanographic Data Center (NODC). Last period shown: April-June 2014. Last diagram update 23 September 2014.

  • Click here to download the entire series of monthly oceanic heat content anomalies since January 1955 (select heat content 1955-now).

  • Click here to read about data smoothing.

 

 

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the West Svalbard Sea (0-20E, 70-80N) since January 1955. The thin line indicate monthly values, and the thick line represents the simple running 37 month (c. 3 year) average. These data may be compared with Arctic sea ice variations and Svalbard surface air temperatures. Data source: National Oceanographic Data Center (NODC). Last period shown: January-March 2014. Last diagram update 26 May 2014.

  • Click here to download the entire series of monthly oceanic heat content anomalies since January 1955 (select heat content 1955-now).

  • Click here to read about data smoothing.

 

 

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the western Barents Sea (20-40E, 70-80N) since January 1955. The thin line indicate monthly values, and the thick line represents the simple running 37 month (c. 3 year) average. These data may be compared with Arctic sea ice variations and Svalbard surface air temperatures. Data source: National Oceanographic Data Center (NODC). Last period shown: April-June 2014. Last diagram update 23 September 2014.

  • Click here to download the entire series of monthly oceanic heat content anomalies since January 1955 (select heat content 1955-now).

  • Click here to read about data smoothing.

 

 

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Average sea temperatures in the upper 300 m at Equator in the Pacific

Location map showing the central Pacific Ocean with location of measurement areas shown in the three diagrams below.

 

Monthly average temperatures in the uppermost 300 m of the Pacific Ocean between 130oE and 80oW according to the NOAA Climate Prediction Center.  For geographical location of transect please see map above. The thin line indicate monthly values, and the thick line is the simple running 7 year average. Reference period: 1981-2010. Last month shown: November 2014. Last diagram update: 2 December 2014.

  • Click here to download the entire series of monthly average temperatures since February 1979.

  • Click here for additional information.

  • Click here to read about data smoothing.

 

Monthly average temperatures in the uppermost 300 m of the Pacific Ocean between 160oE and 80oW according to the NOAA Climate Prediction Center.  For geographical location of transect please see map above. The thin line indicate monthly values, and the thick line is the simple running 7 year average. Reference period: 1981-2010. Last month shown: November 2014. Last diagram update: 2 December 2014.

  • Click here to download the entire series of monthly average temperatures since February 1979.

  • Click here for additional information.

  • Click here to read about data smoothing.

 

Monthly average temperatures in the uppermost 300 m of the Pacific Ocean between 160oW and 80oW according to the NOAA Climate Prediction Center.  For geographical location of transect please see map above. The thin line indicate monthly values, and the thick line is the simple running 7 year average. Reference period: 1981-2010. Last month shown: November 2014. Last diagram update: 2 December 2014.

  • Click here to download the entire series of monthly average temperatures since February 1979.

  • Click here for additional information.

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PDO - Pacific Decadal Oscillation

Typical wintertime Sea Surface Temperature (colors),Sea Level Pressure (black lines) and surface windstress (arrows) anomaly patterns during warm and cool phases of PDO. Figure source: Joint Institute for the Study of the Atmosphere and Ocean (JISAO), a Cooperative Institute between the National Oceanic and Atmospheric Administration and the University of Washington.

 

Annual values of the Pacific Decadal Oscillation (PDO) according to the Joint Institute for the Study of the Atmosphere and Ocean (JISAO), a Cooperative Institute between the National Oceanic and Atmospheric Administration and the University of Washington. The PDO is a long-lived El Niņo-like pattern of Pacific climate variability, and the data series goes back to January 1900. Causes for PDO are not currently known, but even in the absence of a theoretical understanding, PDO climate information improves season-to-season and year-to-year climate forecasts for North America because of its strong tendency for multi-season and multi-year persistence. The PDO also appears to be roughly in phase with global temperature changes. Thus, from a societal impacts perspective, recognition of PDO is important because it shows that "normal" climate conditions can vary over time periods comparable to the length of a human's lifetime. Base period: 1982-2002. The thin line indicate annual PDO values, and the thick line is the simple running 7 year average. Last year shown: 2013. Last diagram update 28 January 2014.

  • Click here to download the entire series of monthly PDO index values since January 1900.

  • Click here to read about data smoothing.

 

 

Monthly values of the Pacific Decadal Oscillation (PDO) according to the Joint Institute for the Study of the Atmosphere and Ocean (JISAO), a Cooperative Institute between the National Oceanic and Atmospheric Administration and the University of Washington. The PDO is a long-lived El Niņo-like pattern of Pacific climate variability, and the data series goes back to January 1900. Base period: 1982-2002. The thin line indicate monthly PDO values, and the thick line is the simple running 37 month average. Here the PDO data are shown since 1979, to enable easy comparison with air the global temperature estimates shown elsewhere. Last month shown: October 2014. Last diagram update: 2 December 2014.

  • Click here to download the entire series of monthly PDO index values since January 1900.

  • Click here to read about data smoothing.

 

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La Niņa and El Niņo episodes

 

Warm (>+0.5oC; red stippled line) and cold (<0.5oC; blue stippled line) episodes for the Oceanic Niņo Index (ONI), defined as 3 month running mean of ERSST.v3b SST anomalies in the Niņo 3.4 region (5oN-5oS, 120o-170oW)]. Base period: 1971-2000. For historical purposes cold and warm episodes are defined when the threshold is met for a minimum of 5 consecutive over-lapping seasons. The thin line indicates 3 month average values, and the thick line is the simple running 7 year average of these. Last 3 month running mean shown: August-October 2014. Last diagram update 7 November 2014.

  • Click here to download the entire series of the Oceanic Niņo Index (ONI) since December 1949 - February 1950.

  • Click here to read about data smoothing.

 

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AMO (Atlantic Multidecadal Oscillation) Index

 

The Atlantic Multidecadal Oscillation (AMO) is a mode of variability occurring in the North Atlantic Ocean sea surface temperature field, identified by Schlesinger and Ramankutty in 1994. The AMO is basically an index of North Atlantic sea surface temperatures (SST).

The AMO index appears to be correlated to air temperatures and rainfall over much of the Northern Hemisphere. The association appears to be high for  North Eastern Brazil, African Sahel rainfall and North American and European summer climate. The AMO index also appears to be associated with changes in the frequency of North American droughts and is reflected in the frequency of severe Atlantic hurricanes.

As one example, the AMO index may be related to the past occurrence of major droughts in the US Midwest and the Southwest. When the AMO is high, these droughts tend to be more frequent or prolonged, and vice-versa for low values of AMO. Two of the most severe droughts of the 20th century in US occurred during the peak AMO values between 1925 and 1965: The Dust Bowl of the 1930s and the 1950s drought. On the other hand Florida and the Pacific Northwest tend to be the opposite; high AMO is associated with relatively high precipitation.

In the diagrams below only originally (raw) AMO values is shown. As is seen from the annual diagram, the AMO index has been increasing since the beginning of the record in 1856, although with a clear about 60 yr long variation superimposed. Often AMO values are shown linearly detrended to remove the overall increase since 1856, to emphasise the apparent rhythmic 60 yr variation.  This detrending is usually intended to remove the alleged influence of greenhouse gas-induced global warming from the analysis, believed to cause the overall increase. However, as is seen in the diagram below, the overall increase has taken place since at least 1856, long before the alleged strong influence of increasing atmospheric CO2 began around 1975 (IPCC 2007). Therefore the overall increase is likely to have another explanation; it may simply represent a natural recovery since the end of the previous cold period (the Little Ice Age). If so, the general AMO increase since 1856 may well represent part of a longer natural variation, to long to be fully represented by the AMO data series since 1856. 

For the above reasons, only the original (not detrended) AMO values are shown in the two diagrams below:

 

Annual Atlantic Multidecadal Oscillation (AMO) index values since 1856. The thin line indicates 3 month average values, and the thick line is the simple running 11 year average. Further explanation in text above. Data source: Earth System Research Laboratory at NOAA. Last year shown: 2013. Last diagram update 6 March 2014.

  • Click here to download the entire series of the Atlantic Multidecadal Oscillation (AMO) index values since 1856 (choose unaltered data).

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Monthly Atlantic Multidecadal Oscillation (AMO) index values since January 1979. The thin line indicates 3 month average values, and the thick line is the simple running 11 year average. By choosing January 1979 as starting point, the diagram is easy to compare with other types of temperature diagrams covering the satellite period since 1979. Further explanation in text above. Data source: Earth System Research Laboratory at NOAA. Last month shown: October 2014. Last diagram update: 2 December 2014.

  • Click here to download the entire series of the Atlantic Multidecadal Oscillation (AMO) index values since 1856 (choose unaltered data).

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Global sea level

Global sea level since late 1992 according to the Colorado Center for Astrodynamics Research at University of Colorado at Boulder. The data have been prepared by Dr. R. Steven Nerem (nerem@colorado.edu) and Dr. Eric W. Leuliette (leuliett@colorado.edu), and are described by Leuliette et al. (2004). The thick line is the simple running 37 observation average, nearly corresponding to a running 1 yr average. The data shown above include the seasonal signal, and have been prepared using the inverted barometer technique (Inverted Barometer = -9.948 * (1013.3 - global average pressure). The inverted barometer does not have much apparent effect on the global mean sea level because the ocean as a whole is not compressible. Data from the TOPEX/Poseidon mission have been used before 2002, and data from the Jason-1 mission (satellite launched December 2001) after 2002. Time is shown along the x-axis as fractions of calendar years. Last diagram update: 17 November 2014.

 

 

Global sea level (thin line) since late 1992 according to the Colorado Center for Astrodynamics Research at University of Colorado at Boulder. Further details are given in the caption to the diagram above. The thick stippled line represents a two-degree polynomium. The polynomium suggests the rate of the ongoing global sea level rise to be slowly decreasing. Time is shown along the x-axis as fractions of calendar years. Last diagram update: 17 November 2014.

  • Click here to download the entire data series since 1992.

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Annual change of global sea level since late 1992 according to the Colorado Center for Astrodynamics Research at University of Colorado at Boulder. The data have been prepared by Dr. R. Steven Nerem (nerem@colorado.edu) and Dr. Eric W. Leuliette (leuliett@colorado.edu), and are described by Leuliette et al. (2004). The annual global sea level change is calculated as the difference between the average global sea level the last 12 months and the previous 12 months. The thick line represents the simple running 3 year average. The data shown above include the seasonal signal, and have been prepared using the inverted barometer technique (Inverted Barometer = -9.948 * (1013.3 - global average pressure). The inverted barometer does not have much apparent effect on the global mean sea level because the ocean as a whole is not compressible. Data from the TOPEX/Poseidon mission have been used before 2002, and data from the Jason-1 mission (satellite launched December 2001) after 2002. Time is shown along the x-axis as fractions of calendar years. Last diagram update: 17 November 2014.

 

The 12-month global sea level change display significant variations, apparently with an approximate 4 year period. These variations are seen to be superimposed on a general falling trend. Overall, since initiation of these satellite measurements, the 12-month sea level rise has decreased from about 4 mm/yr to about 2 mm/yr (using the 3 yr average).

The annual global sea level change shown in the diagram above can be used for estimating the resulting global sea level change at year 2100, compared to now, if the most recent sea level change rate is taken as being representative for the remaining time until year 2100. Clearly this is not realistic, but the result of such an exercise might still have some interest for comparison with computer-generated sea level forecasts, and is shown in the diagram below.

 

 

Estimated average global sea level change until year 2100, according to sea level change values provided by the Colorado Center for Astrodynamics Research at University of Colorado at Boulder (see figure above). The estimated average global sea level change is calculated using a simple extrapolation of the most recent observed annual sea level change (diagram above, please see also note below). The thick red line represents the simple running 3 year average of this estimate. Time is shown along the x-axis as calendar years. Last diagram update: 17 November 2014, with a prognosis (red line) of about 38 cm average global sea level rise until 2100.

 

Note: Using the 3 year average shown in the diagram above, based on observed sea level changes, around 1999 the total sea level change from then until year 2100 would have been estimated to about 40 cm, in 2005 to about 30 cm (year 2005-2100), and in 2010 to about 22 cm (year 2010-2100). On July 14, 2012, the prognosis would be about 16 cm sea level increase until 2100. It is interesting that this simple empirical forecast has shown a steady trend towards lower values since about 2002.

 

 

TEMPORAL STABILITY OF SEA LEVEL DATA

Global sea level since late 1992 according to the Colorado Center for Astrodynamics Research at University of Colorado at Boulder. The two data series show data available on July 20, 2009 (red), and the newest data available (blue). The thick lines indicate the running one year averages. The difference between the two dataseries is mainly due to a change of the zero reference level. In addition, the overall sea level increase rate until April 2009 is somewhat larger in the newest data, but not much. Last diagram update: 6 June 2014.

 

 

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