Data Flow

The data flow within the UOT DAC system is sufficiently complicated and woven into operations of the GTSPP (Global Temperature Salinity Profile Project) that it is useful to draw a diagram that illustrates it.  The convention used here is to refer to low and high resolution data.  Low resolution data normally are those which are in sent in real-time (IGOSS, Integrated Global Ocean Services System, defines real-time to be any data exchanged within 30 days of collection) formats of BATHY or TESAC code.  Typically these report observations at inflection points in a profile.  BATHY permits reporting temperatures to 0.1 degrees C as is most often used for XBT data, TESACs permit reporting both temperature and salinity profiles, both to two decimal places.  High resolution data are those that reflect the sampling capabilities of instrumentation.  For example, CTD data typically are handled at 1 m resolution and are considered to be high resolution data.

The diagram below makes no distinction between data of primary interest to GTSPP and those of interest to WOCE.  Generally, the low resolution data are of less interest to the UOT.  However, there is always a considerable delay in some high resolution data reaching the archives, and it is considered advantageous to have at least the low resolution data if the high resolution data have not yet arrived.  Also, by monitoring the data received in real-time, it is possible to know where ships are operating and collecting the high resolution data (usually using XBTs).  One can look at the sampling along WOCE lines, and the distribution over the world's oceans and so influence the sampling strategy before the end of the programme.  For these reasons, the UOT DAC system is a assembly of partners each undertaking specific aspects of the work.

The top part of the diagram deals largely with low resolution data flow.  The bottom shows the data flows into and out of the Continuously Managed Database, CMD, established at the U.S. NODC.  Arrows indicate the direction of data flow, and dashed lines indicate connections currently under development.

Low Resolution Data Flows

The U.S. National Oceanographic Data Center, NODC, continues to act as the conduit through the Internet for low resolution data from the National Meteorological Center, NMC, each day.  As well, the Marine Environmental Data Service, MEDS, receives data from its own link to the GTS (Global Telecommunications System).

MEDS processes BATHY and TESAC data taken from the GTS by the Bundesamt fur Seeschiffahrt und Hydrographie, BSH, and the Japanese Meteorological Agency, JMA, and forwarded after the end of each month by diskette, tape or Internet.  These data and the daily files are used in the production of the GTSPP monthly reports to the IGOSS Co-ordinator.  Data in these files, which are missing from the daily files are added to the GTSPP data flow.

Data exchange is shown from the Japanese Oceanographic Data Center, JODC. These data are transferred electronically to MEDS at the end of each month. These are data collected from Japanese fisheries and defence ships. Temperatures are sampled at 0, 100, 200 and 400 m only and time of day is not available for the stations.

There is also an exchange of low resolution data from FNOC and labeled as U.S. Navy data.  These files arrived sporadically. These contain declassified BATHY messages from U.S. naval ships which are available for exchange.  The data may have been collected anytime within the last 6 years.

The box labeled Russia represents the flow of low resolution data from the Russian Navy.  This exchange is still under development.

The box labeled NAVOCEANO represents the US Navy oceanographic centre in Bay St. Louis.  Data files are transferred to them on the same schedule as to NODC.

There is a box labeled National Users. Data are forwarded each month to oceanographic institutes on each coast of Canada.  As well, MEDS sends files three times a week to international users in the U.S. and New Caledonia.

High Resolution Data Flow

On the lefthand side of the figure is represented the three centres, Miami, Scripps and CSIRO that carry out scientific quality control of data.  The data are relayed electronically from NODC each year.  Each centre has the responsibility to return the data with the updated quality control indicators to the NODC.

The low resolution data are forwarded to the Australian SOC (an IGOSS Specialized Oceanographic Centre) and contribute to the holdings of this agency.  In a letter to the IOC, the Australians stated that the volume and quality of the GTSPP data exceeded what they were able to acquire through their own resources and hence they would use GTSPP data as the basis of their data holdings.  Work also is underway to provide data and information to the SOC for the Southern Ocean in Argentina.

The low resolution data relayed to NODC are passed along to Aants Leetmaa at NMC for use in his coupled ocean-atmosphere model.  He receives the files three times each week and the data are included in his weekly model runs.  Likewise, the Bureau of Meteorology Research Centre, BMRC, in Melbourne, Australia, copy the files for use in their modelling.

NODC also relays temperature profile data to the World Ocean Circulation Experiment Subsurface Data Center for the Upper Ocean Thermal programme situated in Brest, France. The data are sent each month via Internet.

On the right of the NODC box is the Global Ocean Data Archaeology project, GODAR.  This has been spearheaded through the efforts of the World Data Centre A, WDCA

Another box represents the other World Data Centres. As data reach the NODC, they become available to other data centres around the world.

There are at least two routine users of the low resolution data and forwarded by NODC.  One is a researcher at the University of Delaware, and a second at the Jet Propulsion Laboratory.