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Moored Buoy DataContents |
Background
National weather agencies and diverse research programs maintain moored buoys for different periods of time to collect marine meteorological and sometimes oceanographic data. Examples include the equatorial moorings in Pacific, Atlantic, and Indian Oceans managed by the Tropical moored buoy Implementation Panel (TIP). Buoys, whether moored or drifting, are overviewed by the Data Buoy Co-operation Panel (DBCP) of JCOMM.
A number of nations also maintain networks of coastal buoys that gather data at high frequency. Often these are maintained and operated by national weather agencies. Generally, all of the data are made available in real-time. Ocean research programs also deploy moored platforms and in most cases these, too, record meteorological information as well as oceanographic measurements. It is not the case that all of these data get to national agencies and are distributed in real-time.
An overview of the tropical moored buoy programme is described in an OceanObs'09 Community White Paper.
An international programme for deep ocean moorings, OceanSITES, has begun recently. OceanSITES is a worldwide system of long-term, deepwater reference stations measuring dozens of variables and monitoring the full depth of the ocean from air-sea interactions down to 5,000 meters. Not all of the variables in the complete suite have a place in present real-time data exchange formats. An OceanObs'09 Community White paper describes this programme.
Using National Focal Points
Step 1: Identifying the buoys
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: Preparing data
The national focal point will request information about your data sources that will help ensure that it is used appropriately. Important metadata includes the instrumentation used, descriptions of how the instruments were deployed, the names of the measured variables, the units of measurement, the precision and accuracy of the measurements, their complete location (both horizontal and vertical dimensions), the relationship between the time value and the sample period of each parameter, details of any processing such as averaging, calibration, etc. that may have occurred, and so on. Any information that would be needed by someone else to correctly use the data should be provided.
Step 3: Formatting the data
The format and mechanism for data transport will be established with your national agency. Different national focal point agencies may have their own allowed formats for incoming data. For example, the NDBC, accepts data in BUFR and in two alternative formats. It also provides software to assist users in creating compliant files.
Step 4: Distributing the data
Once the data provider begins sending data to the national focal point, the data should be monitored to ensure that any errors are found and corrected if possible. Any change in location of a moored buoy should also be reported immediately. If the national focal point is providing quality control services, they may inform the data provider of any problems seen; the data provider should likewise notify the national focal point if problems are detected, if the buoy position changes, if instruments are replaced or if service interruptions are expected.
Not using National Focal Points
If you do not have a national focal point or wish to handle data operations yourself, you will need to follow the following steps.
Step 1: Identifying the buoys
The DBCP is an important resource for anyone contemplating deployment of a moored platform. Visit the DBCP web site or contact the DBCP Technical Co-ordinator for advice.
Before your moored buoy can report data in real-time it needs to be assigned a unique World Meteorological Organization (WMO) identifier. Each country has been assigned a block of numbers for its use and the country's national focal point can provide identifiers for you. If your country has never deployed moored buoys before or never reported such data in real-time, contact the DBCP Technical Co-ordinator.
Step 2 Getting data ashore via Service Argos
Use of the Service Argos system is one of the ways that data are transmitted from buoys to shore. If you are interested in learning more, contact Service Argos directly, or talk to the DBCP Technical Co-ordinator.
Step 3: Distributing data via Service Argos
When Service Argos manages the insertion of the data onto the GTS, a buoy operator needs to provide sufficient information to tell them how to extract the data from the message sent by the PTT. 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 on the GTS in both BUOY code (a character code form) and BUFR (the binary code form). Information on GTS formats is available in the document “Formats for real-time Data Exchange”.
Step 2: Getting data ashore using the Iridium system
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 center 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. The operator adds a step to the local processing system to create a file with new data to be sent via ftp to the national focal point.
Step 3: Distributing data when using the Iridium system
Iridium service providers, with the exception of CLS (english or 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 on the GTS.
For those using other Iridium service providers, it is possible to make arrangements with your country’s DBCP National Focal Point to submit the data for you. As example for the US, this is the National Data Buoy Center (NDBC).
Other Means
If neither Service Argos or the Iridium system meet your requirements, you will need to find another way to get data from the buoy to your shore-side processing facility, to prepare the data for real-time distribution and upload to the GTS. You are advised to consult the DBCP technical co-ordinator to discuss your issues. Also, you will need to contact your national meteorological service which is your gateway to the GTS. As well, they may be aware of other moored buoy operators in your country, outside of your knowledge, and can help you get in contact with them.
Step 4: Quality control
The responsibility for basic quality control can be handled by the data provider or by the national focal point. 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
GTS: http://www.wmo.int/pages/prog/www/TEM/GTS/index_en.html
JCOMMOPS (for general information on ocean observing programmes): www.jcommops.org/
Subsections of this Article
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Information about this article
Short title: Moored Buoy Data
Description: This provides information about exchange of data acquired by moored 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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