From Ocean Teacher Library
Drifting Buoy DataContents |
Background
An international drifting buoy programme had its origins in the First GARP (Global Atmospheric Research Programme) Global Experiment in 1987. Since then, considerable resources have been expended on the programme so that today there is a well co-ordinated program for exchanging data and information on manufacture, deployment, telecommunications and data management for drifting buoys. This is focused in the Data Buoy Co-operation Panel (DBCP) of JCOMM. Anyone contemplating deploying drifting buoys should contact the chairof the Panel or the DBCP Technical Co-ordinator.
A number of nations also deploy drifting buoys for short term experiments or to assist in search and rescue operations. It is unusual for these data to reach the international system, but they can be a valuable adjunct if they were reported.
An description of the data management system for the drifting buoy programme is provided in an OceanObs'09 Community White Paper.
Step 1: Identifying the buoys
Before you can distribute data in real-time on the GTS, you must have a World Meteorological Organization (WMO)identifiergiven to your buoy. The DBCP Technical Co-ordinator will be happy to assist in all aspects of deploying drifters.
The DBCP has designated national focal points to assist buoy operators. If you are planning to work with your national focal point, contact them well ahead of your deployment and request information on their submission guidelines. They may assist you in acquiring a WMO identifier for your buoy, provide guidance on which of your measurements are suitable for insertion onto the GTS, and help ensure that you follow conventions for these parameters. They will also be able to describe the data formats that they can accept, and provide you with a mechanism for submitting your data, usually in the form of an FTP server address and user account.
Step 2: Getting data ashore
Using Service Argos is a common way for data ashore from drifters. Abuoy operator needs to provide sufficient information to explain how to extract the data from the message sent by the PTT. Service Argos then configures their decoder to read the data transmission from the buoy and to extract the observations made. The DBCP Technical Co-ordinator can help with this process, especially because they are located very near the Service Argos offices in France.
The Iridium cell phone system is another way to get data ashore. The advantages of this is that there is greater bandwidth for at sea communications (though power requirements are higher). This allows sufficient bandwidth such that most if not all of the data can be transmitted in a single message to a receiver. Data are typically sent from the buoy to the operator’s shore-side processing centre using one of several Iridium modes, often Short Burst Messaging (SBD), which delivers data as an email attachment, to be processed locally, based on the contents of the payload.
There also may be facilities in your country for managing the telecommunications from drifters to shore. It is a good idea to talk to your national focal point to explore this possibility.
Step 3: Distributing the data
When Service Argos manages the insertion of the data onto the GTS, their processing software extracts observations from the message transmitted from the drifter, reformats the data to appear on the GTS into both BUOY code (a character code form) and BUFR (the binary code form), and inserts the data onto the GTS.
Iridium service providers, with the exception of CLS (englishor french), do not offer the option to forward data to the GTS automatically. For those who purchase Iridium service through CLS, obtain a form (GTS Technical File) which will provide sufficient information for CLS to extract the data from the Iridium message. Service Argos then configures their decoder to be able to read the data transmission from the buoy to extract the observations made, reformat the data to appear, and forwards the data to the GTS.
If another Iridium Service Provider (not Service Argos) or some other telecommunications system is used to get data ashore, the onus is on the buoy operator to prepare the data in the correct format and for insertion onto the GTS. As noted above, BUOY or BUFR encoding is required for the data. Details of this format are described in the digital library document “Formats for Real-time Data Exchange”.
Since National Meteorological Services are the only agencies with direct access to the GTS, you will need to contact your country's national meteorological serviceto make arrangements to move the data from your agency to theirs. It is worthwhile to contact them as soon as possible since they may already have facilities in place that can assist you in getting the data formatted correctly for GTS distribution.
Step 4: Quality control
The responsibility for basic quality control can be handled by the data provider or perhaps by an agency managing insertion of the data onto the GTS. Data providers should inquire if such services are available for them. Data providers are encouraged to remove the most egregious errors before the data are distributed. Data providers are strongly urged to examine information about DBCP recommended quality control procedures.
Additional Resources
FGGE: http://unesdoc.unesco.org/images/0003/000348/034822eb.pdf
GTS: http://www.wmo.int/pages/prog/www/TEM/GTS/index_en.html
JCOMMOPS (for general information on ocean observing programmes): www.jcommops.org/
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Information about this article
Short title: Drifting Buoy Data
Description: This provides information about exchange of data acquired by drifting buoys.
Expertise level: beginner
Author: bob.keeley
Approval status: approved
Approved by: bob.keeley
Last change: 2012-2-10
Subsection of: Exchanging Ocean Data in Real-time
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