Sea Surface Height


The sea surface height (SSH) or height of the ocean surface is affected by tidal forces, ocean circulation and variations in the gravitational field. The daily variation from the mean sea surface height is the sea surface height anomaly (SSHa), which is observed by satellite altimeters. The observations from multiple altimetry satellites are merged into daily gridded data maps (historical data maps). Robert Leben (leben@colorado.edu) from the Colorado Center for Astrodynamics Research (CCAR) produces these gridded data maps. For convenience purposes, the daily data fields were combined into yearly data files ranging from 2007 through 2012. Click on link for the corresponding year to download the data file or to view an animation of the data.

For more information and to see which other years are available, visit the Colorado Center for Astrodynamics Research (CCAR) Global Historical gridded SSH data viewer website: (http://eddy.colorado.edu/ccar/ssh/hist_global_grid_viewer) and/or contact Robert Leben (leben@colorado.edu).

2004

Download NetCDF File

2005

Download NetCDF File

2006

Download NetCDF File

2007

Download NetCDF File

2008

Download NetCDF File

2009

Download NetCDF File

2010

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2011

Download NetCDF File

2012

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2013

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2014

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2015

Download NetCDF File

2016

Download NetCDF File


Calculation of  sea surface height anomaly

The sea surface height anomaly (SSHa) for a specific day can be determined by using the formula provided by Robert Leben (leben@colorado.edu). The formula calculates the SSHa relative to the AVISO mean sea surface CLS 11.

SSHa = SSH + mean_alt_hist_cls11_1993_1999 - mean_model_93_99.

The 3 terms needed are:

  1. the gridded sea surface height (SSH) for the day in question,
  2. the mean of the yearly mean sea surface height anomaly (SSHa) for the time period 1/1/1993 -12/31/1999 (mean_alt_hist_cls11_1993_1999),
  3. the mean sea surface height for the time period 1/1/1993 -12/31/1999, which was calculated with the University of Colorado Gulf of Mexico model (CUPOM). 

Both files (2, 3) are provided below in netcdf format. The files contain Longitude (280° - 262°, with 0.25° spacing), Latitude (31° – 18° N with 0.25° spacing), and sea surface height anomaly data in cm.

mean_alt_hist_cls11_1993_1999.nc

mean_model_93_99.nc

 

For more information:

Leben R.R, G.H. Born, B.R. Engelbrecht. 2002. Operational Altimeter Data Processing for Mesoscale Monitoring, Marine Geodesy, 25:3-18

 

In order to better visualize the difference between SSH and SSHA, 5 graphs have been created.

Mean historical ssha data, Mean ssh model data, SSH, SSH + Mean historical ssh and SSHa.