Alison R. Gray and Stephen C. Riser


About AGVA

AGVA (Absolute Geostrophic Velocities from Argo) is a set of monthly estimates of absolute geostrophic velocities in the global ocean at 1° lateral resolution and on 29 pressure surfaces from 5 db to 2000 db, computed from observations from the Argo array of profiling floats. The estimates currently span December 2004 to November 2010.

Download the data files below, or have a look at the gallery. The supported data format is netCDF. Please contact us if you have problems reading these data files and would like to request a different format.

This website is preliminary and will be improved over time. The current version of AGVA is 1.1. We anticipate updating AGVA in the future to include estimates for later months as well as methodology improvements that may be implemented. Please email us if you want to be notified when AGVA is updated.


Description

AGVA is described in the following paper:
Gray, A. and S. Riser, 2014. A Global Analysis of Sverdrup Balance using Absolute Geostrophic Velocities from Argo. J. Phys. Oceanogr. doi:10.1175/JPO-D-12-0206.1, in press.

Disclaimer

We have computed AGVA carefully and examined the estimates for errors, but please let us know if you find any issues. You are welcome to use AGVA for any non-commercial purposes but do so at your own risk, as we cannot accept any liabilities.

Citations

Please cite Gray and Riser (2014) when using AGVA. We would like to maintain a bibliography of publications using these velocity estimates, so please email us details of your publications using AGVA. In addition, please let us know about any other uses of AGVA and your experiences using these estimates, as well as any feedback and suggestions for improvement.


Downloading AGVA

Global monthly 1° x 1° netCDF files are available below, organized by year. Each zipped file is on the order of 550 MB.

Variables in files:
Pressure
Latitude
Longitude
Month
Geostrophic streamfunction
Zonal geostrophic velocity
Meridional geostrophic velocity
Standard deviation on zonal velocity estimate
Standard deviation on meridional velocity estimate
(The standard deviation estimates are preliminary and will be improved in the next update of AGVA.)

Note that the standard deviation estimates are separated into a component associated with the seasonal cycle and a monthly component. The seasonal cycle component of the standard deviation is the same for each January, February, etc., regardless of year, and this must be taken into account when averaging over different years. The monthly component of the error is uncorrelated.

AGVA files

  Geostrophic velocities Potential temperature and salinity
2004 AGVA v1.2 vel 2004 coming soon
2005 AGVA v1.2 vel 2005 coming soon
2006 AGVA v1.2 vel 2006 coming soon
2007 AGVA v1.2 vel 2007 coming soon
2008 AGVA v1.2 vel 2008 coming soon
2009 AGVA v1.2 vel 2009 coming soon
2010 AGVA v1.2 vel 2010 coming soon