10-day mean Surface Currents around Japan

Term: from January 2020 to latest
Area: 16.75N - 56.25N, 113.5E - 163.5E, 1/10 degree x 1/11 degree
Method & Explanation:
NPR-4DVAR is the data assimilation component of MOVE/MRI.COM-JPN, the JMA's operational system for monitoring and forecasting coastal and open-ocean states around Japan. 
It consists of an eddy-resolving model for the North Pacific and a four-dimensional variational (4DVAR) assimilation scheme. 
Observations of satellite along-track sea level anomalies, gridded sea surface temperature derived from MGDSST(*), 
in-situ temperature and salinity profiles are assimilated by 4DVAR with 10-day assimilation window. 
For more information, see the article of Hirose et al. (2019).

* MGDSST: https://www.data.jma.go.jp/goos/data/rrtdb/jma-pro/mgd_sst_glb_D.html

Data Format:
One data file consists of 795 records, one header record and 794 data records. 
The header record contains the year, month, and [early/middle/late] of month in four digits each from the left. 
The surface currents are divided into the zonal and meridional component and the grid point values (GPVs) 
of the zonal one are stored on a 397-record block from 2nd record, those of the meridional one on the next block from 399th record.
The direction information is stored on the first record of each 397-record block. 
Where 'Eastward_Component' and 'Northward_Component' are designate eastward and northward component with a positive value, respectively. 
The GPVs along 56.25N are stored on the 2nd record of the block, those along 56.15N are on the 3rd record of the block, 
and those along 16.75N are on the 397th record of the block. 
Each record contains the 551 GPVs from 113.5E to 163.5E at the interval of 1/11 degree in longitude. 
Each GPV domains four digits in the unit of 1 cm/sec. 
The GPV is 9999, if the current is not determined or the grid point is below the bottom of the ocean. 
Here, the '10-day' is determined as follows.  Three '10-day' analyses are made in each month, 
and the first 10-day is from the first to the 10th day of the month, 
the second is from 11th to 20th and the third is from 21st to the last day of the month. 
About two months after the near-realtime analysis data is first created, it is replaced by the realnalysis data of which file name starts with 're_'.

References:
Hirose, N, N. Usui, K. Sakamoto, H. Tsujino, G. Yamanaka, H. Nakano, S. Urakawa, T. Toyoda, Y. Fujii, N. Kohno (2019):
Development of a new operational system for monitoring and forecasting coastal and open-ocean states around Japan 
Ocean Dynamics 69(11-12), 1333-1357

For further information, please contact to administrator of the Regional Real Time Data Base at neargoos@climar.kishou.go.jp.