Structure of the File
File Name format to be
used: The format of the file name is a combination of WMO
Recommendation 2, FTP
procedures [1,025K pdf] (described in CBS XII, Geneva, 29 November - 8 December 2000) and
the U.S. Telecommunication Gateway TOC
Directory and File Name Standard. The WMO has developed a NEW FILENAME FORMAT as a recommended practice for file delivery (FTP PUSH) over the GTS. This new
recommendation will become published as part of WMO Manual 386 on 3 November 2003. The Gateway will begin using this new recommendation.
File Name Practice Currently Used
(see the new filename guidance for future use)
Old Format
cccc[_si.aaaa(aaaaaa)]_dt.hhnnss
where;
_si. & _dt. are keys (do not change) see the TOC Directory and File Name Standard
cccc = Four letter ID of transmitting NMC or center; documented in WMO
Manual 9, or Nationally defined
[si.aaaaaaaaaa] is an optional group to allow additional file name definition for multiple
data processes within a providing data supplier ( Length of definition
aaaaaaaaaa is a variable field upto 10 characters as needed. )
dt.hhnnss = hour-minute-second the file was generated for transfer (file
names can not be duplicated within a day). The {SI|si}.(aa)aaa and {DT|dt}.hhmmss fields are taken from the Gateway TOC Directory and File Name Standard
Example
filename
Using assumed account established
with RTH Melbourne (AMMC)
ammc_dt.211515 |
File Content Structure
The files sent may contain
one or more bulletins. Each bulletin in the file (including the first one) must
be prefixed with a flag field to separate
bulletins. The bulletin size should meet the WMO standard to achieve switching
of the bulletins onto the MTN of the GTS.
The receiving center will
detine which "flag field separator" the data providers will use. This flag
field is written in International Alphabet No. 5 and is always required in the
contents of the file, even for a one bulletin product.
An example
Bulletin Flag Field Separator
format
####lllbbbbbb####"0A" [Note]
where;
#### = 4 pound signs
lll = length of prefix
bbbbbb = length of bulletin
"0A" = ASCII line feed
Example
Content
####018000263####
SIAU40 AMMC 261500
RRA
AAXX 26154
94129 35/// /1305 10281 30066 40089
57008=
94289 35/// /1213 10286 30086 40095 57009=
94307 35/// /1503 10254 30111 40151 52004=
94371 35///
/1115 10279 30108 40114 57010=
94379 35/// /0000 10281 30108 40117
57013=
####018000093####
SIIN23 DEMS 261500 RRA
AAXX 26154
43063 32996 02706 10280 20134 39456 40067 333
59001= |
Note: For potentually large bulletins, such as large
GRIB or BUFR model derived products it was necessary to develop a new OPTION 2 to allow large capacity FLAG FIELD (option 2) form to be used. |
Portal Service Establishment
The file transfer
requires that an account be established with the U.S. Telecommunication Gateway
(RTH Washington). The RTH will provide the computer location for FTP "send"
transfers and will provide the requesting provider with the following
information:
- The server URL address
- A unique portal ID & password for the file
transmisson.
Establishing this account requires an initial exchange of
information between the sending center and the RTH. Contact RTH Washington by email to
request an account. |