MEDS SVP Archives

Since 1992, MEDS has received SVP Drifter data from AOML every 6 months. The number of individual reports from the buoys in each of the submissions is shown in Table 1.

Table 1. Number of reports from buoys in the Krig files received at MEDS from AOML for the period of January 1979 to December, 2000.

The types of data received by MEDS from AOML are:

(a) Raw data files as the GDC received from Service Argos. These files are kept as received for future reference. These contain original values of temperature, salinity, air pressure, etc.

(b) "P" file (Position file) edited data which provides for each experiment Buoy ID (Argos number) the date, time and position (latitude and longitude).

(c) "S" file (Sensor file) edited data which provides for each experiment Buoy ID the date, time and temperature values.

(d) "Krigged" file data have interpolated values every 6 hours for every buoy. See document 'Interpolation Scheme' to learn more about how this file is created.

(e) Directory file which provides the connection between Buoy IDs (Argos and WMO numbers); this directory file also provides pertinent information on drogues and deployment.

MEDS merges the "P" and "S" files together allowing for a ±15 minute window to match the date/time entries from both data sets; the merged output files are archived by experiment number and are available to the users; the data from these files can be retrieved by area and time frame from one or many experiments. Into this merged file are inserted whatever other sensor data are available in the raw files.

Readers wishing access to these data should visit MEDS web site. You may use the MEDS link shown on the welcome page.

The KRIG Archive

The KRIG data file constitutes the output product of the WOCE Surface Velocity Programme. The entire data set submitted by AOML is archived by MEDS and is available to users; the data from this file can be retrieved by area and time frame. The experiment number can also be used as a retrieval criteria. Comma separated value formatted files are available from MEDS web site. Data in other formats can also be obtained by contacting MEDS directly. The data from this file can be plotted as points on a map thus representing the path followed by each buoy while drifting. A map can be drawn for a specific region of the world, for the entire world, or for the region occupied by a selected set of buoys. Selections and maps can be drawn based on time periods as well.

A meta file assembled by the Global Drifter Center is also available from MEDS. This file contains detailed engineering descriptions and calibration information for each SVP drifter contained in the raw data and krigged data archives. The meta file has been created with FileMaker Pro and can be sent by FTP upon request in full or for selected experiments or Argos numbers.

The KRIG archive contains information about the following measurements or calculated values.

1. The Argos ID. MEDS combines this with the year to create a unique number for each buoy.
2. The date and time is stored as a four character year, 2 character month, 2 character day of month, and 4 character hours and minutes.
3. The position is stored as decimal latitudes and longitudes.
4. Each time a record is created or modified by MEDS the date of this action is stored.
5. Sea surface temperature.
6. Eastward component of current.
7. Northward component of current.
8. Surface current speed.
9. The error in the latitude (from the interpolation method).
10. The error in the longitude (from the interpolation method).
11. The error in SST (from the interpolation method).
12. The latitude of buoy deployment.
13. The longitude of buoy deployment.
14. A code for the drogue type.
15. The date that the drogue was lost.
16. The originator's experiment number
17. The date of deployment.
18. The date of the last message received from the buoy.
19. A code indicating why messages ceased from the buoy.
20. The WMO number of the buoy.