A set of monthly absolute geostrophic velocity data of the North Pacific Ocean calculated by Prof. Dr. Dongliang Yuan and colleagues, can be accessed from the following site.

http://pan.baidu.com/s/1qWwJdjI

Password: umgd

The velocity is calculated using the P-Vector method of Chu (1995, 2006) and cover the period of January 2004 through December 2011. The calculation is based on the gridded temperature and salinity data of Argo floats, with a 1º×1º horizontal resolution and on 58 vertical layers in the top 2000 m of the ocean, produced by Scripps Institution of Oceanography through optimal interpolation at the following site.

http://www.argo.ucsd.edu/Gridded_fields.html

Considering that the motion in the upper mixed layer of the ocean generally does not follow the potential density and potential vorticity surfaces, we first calculate the absolute geostrophic velocity using the P-Vector method in the intermediate layers between 800-2000 dbar. Above the 800 dbar, the geostrophic currents were determined by the simple dynamic height method, using the geostrophic currents at the 800 dbar as the reference velocity.

The geostrophic velocity of each month was written in one file in netCDF format. The latitudinal, longitudinal and vertical coverages are  1°N - 59°N, 120°E - 76°W, and 2.5 dbar - 1900 dbar, respectively, the detailed information of which is contained in the metadata of file.

Please cite the following references when using the data in your publications and feedback us any problems you should encounter in using the data. Thank you.

References:

Zhang Z. C., D. L. Yuan and P. C. Chu, 2013: Geostrophic meridional transport in tropical Northwest Pacific based on Argo profiles. Chin. J. Oceanol. Limnol., 31, 656-664.

Yuan et al., 2014: Geostrophic Circulation in the Tropical North Pacific Ocean Based on Argo Profiles. J. Phys. Oceanogr., 44, 558-575.