Chapter-7

CHAPTER 7

DATA DISSEMINATION

7.1 Introduction. Radiosonde and pibal observations are disseminated for operational use by means of various communication services described below. In addition, these observations are archived for research and other use and disseminated by the archive centers. Under agency control, all observations shall be disseminated by means of one of the communication services and archived by one of the archival centers. This Handbook recognizes that some observations may be taken for local use only.

7.2 Global, Regional, and National Telecommunications. The GTS comprises the data collection systems of the World Weather Watch (WWW). The GTS ties together the three World Meteorological Centers (WMCs): Melbourne, Australia; Moscow, Russia; and Washington, DC; and their various supporting regional and national systems. The WMCs receive data from the various Regional Telecommunication Hubs (RTH) within their zone of responsibility. The systems for collection of data at the RTHs from the various National Meteorological Centers (NMCs) in each country comprise the Regional Telecommunications Network. Lastly, the individual national configurations for the collection of data within countries make up the National Telecommunications Systems for meteorological data.

7.2.1 The Regional Telecommunications System. WMO Regions IV and V, North America and Southwest Pacific Ocean, contain rawinsonde sites operated by the United States as part of the Global Observing (GOS) Network. Exceptions are the sites operated by the U.S. DoD at Diego Garcia located in the Indian Ocean, and Ascension Island in the Atlantic Ocean (both in Region I.) (See Appendix C - List of U.S. Rawinsonde Stations.)

7.2.2 National Telecommunications Systems. The principal systems for collecting and exchanging data among rawinsonde units and other facilities within the coterminous U.S. are NOAA's AFOS; Alaskanet, Pacific Communication Systems; and DoD's AWN.

The major hub for the AFOS is the NWSTG located in Silver Spring, Maryland, and for the AWN, Tinker AFB, Oklahoma. Each of these facilities is responsible for transferring data between one another and to and from all other national circuits. The NWSTG is the U.S. interface to the GTS and provides distribution to international users. Each system is designed to prevent system failure and data losses by having multiple data flow paths. If a failure occurs at a point that inhibits flow of data in one direction, data will continue to flow in the other direction. Reports from the DoD stations which form part of the GOS are entered onto the GTS through the NWSTG. Other DoD sites communicate their data only on the AWN or its branch circuits.

7.3 WMO Index Numbers. A station index number in the symbolic form IIiii is included in the reports of meteorological observations made at fixed land meteorological stations or aboard ships using land code forms. The station index number is composed of the WMO block number (II -representing Identification) and a three-digit national station number (iii). The two-digit block number defines the area in which the reporting station is located.

7.3.1 Assignment of International Station Index Numbers. Each station within the WWW Global Observing Network which communicates synoptic observations (surface and/or rawinsonde) or other specified types of data (e.g., CLIMAT, CLIMAT TEMP, etc.) has a five digit international station index number assigned to it. These numerical designations facilitate identifying, switching, and processing the bulletins and data that the individual stations provide. Quality control is imperative to ensure the accurate transmission of station numbers. An erroneous index number can cause either a loss of the report or assignment of the data to the wrong location if the erroneous number happens to be that of another station. Block number designation assignments are made by the WMO; station numbers assignments are delegated to member countries. If a station moves, even a short distance, a new index number may need to be assigned. Stations shall be responsible for obtaining a proper index number.

7.3.2 Obtaining Assignments of WMO Block/Station Numbers. Responsibility for the assignment of WMO Block/Station Numbers for U.S. rawinsonde stations rests exclusively with the Permanent Representative of the U.S. to the WMO. Agencies requiring assignments of WMO index numbers for any of their stations shall direct their requests to:

Headquarters, National Weather Service - NOAA

Attn: W/OSO242

Silver Spring Metro Center 2

Silver Spring, MD 20910

Requests for block/station number assignments must be made in writing and the following information about the station shall be provided:

• Name of the Station	     	• Date operations are to begin
• Latitude			• Synoptic programs to be carried out
				(i.e., synoptic, rawinsonde, CLIMAT,
				etc.)
• Longitude 			• Schedule of
				  planned synoptic times for data
				  transmissions
• Station elevation
information, in meters, including
- H_P- the datum level to which barometric reports at the station refer (station pressure).

- H - the elevation of the ground in the immediate vicinity of the station for stations not located on aerodromes

or

H_A - official height of the aerodrome for stations located on aerodromes.

- Elevation of the release point (if different than station elevation).

7.4 Transmitting Rawinsonde Reports. The complete observation shallbe transmitted not later than 30 minutes after termination of the ascent. The coded report containing data for pressures greater than 100hPa (Parts A & B, Appendix E) shall be transmitted no later than 45 minutes after the standard observation time ( 0000 or 1200 UTC). If, owing to unforeseen circumstances, less than a full data report can be provided, stations shall do the following:

• When no data are available, a report giving the coded reason shall be filed within the scheduled deadline.

• When some data are available but a full report cannot be filed, a partial report shall be transmitted within the time scheduled for a full report. In addition, the coded reason for providing only a partial report shall be included with the partial report.

The times shown in Table 7-1 are the maximum times allowable for transmissions. In the event a complete report is not ready at these times for any reason, rawinsonde sites shall communicate as much data as are available by the deadline and include in the message(s) the appropriate 101-- group explaining the reason for missing data (see Appendix E-II.2.9). As soon as the remaining data for the Part are available, a retransmission of the entire Part shall be made.

Table 7-1. Deadlines (in minutes after release time R) for Transmission

of Scheduled Synoptic Rawinsonde Observations

CODE FORM: TEMP Part A Part B Part C Part D	CODE FORM: PILOT Part B Part D
R*+ 90 R + 90 R + 180 R + 180 Minutes Minutes Minutes Minutes	R + 120 R + 180 Minutes Minutes

* R is the balloon release time, not the observation time. [Ref 12, Part III]

7.4.1 RADAT. This coded report is composed of information concerning the freezing level and should be transmitted 15 minutes following the standard time of observation. Procedures for encoding RADAT reports are given in Appendix E, Table 0421.

7.5 Data Archiving. There are many critical non-real-time users of rawinsonde observations in climatology and research. In order to make rawinsonde observations available to retrospective users, all observations shall be sent to major data centers in compliance with the standards defined in Appendix F. Three major data centers maintain historical rawinsonde data: NOAA's NCDC; Operating Location-A (OL-A) of the U.S. Air Force's Combat Climatology Center (AFCCC); and Fleet Numerical Meteorology and Oceanography Detachment. These Centers are located in Asheville, NC. See Appendix F for details.

Chapter 6
Chapter 8
Table of Contents
Publications List
Home