1. The GEONETCast Alert Channel and CAP over GTS
Simon Elliott
EUMETSAT
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

2. Distribution of satellite products
EUMETSAT operates meteorological satellites
Satellite data are processed to derive a range of products (images, radiance data, wind information, soil moisture, fire detection, etc.)
Products are produced operationally in near real time in a variety of formats
BUFR - GRIB - JPEG - ASCII - netCDF - HDF
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

3. Distribution mechanisms
Several mechanisms are used to distribute satellite products
EUMETCast/GEONETCast
Satellite DVB-S multi-cast service
Easy access, many users, almost global coverage
Global Telecommunication System, GTS
Global network connecting NMHSs
Limited access, highly controlled, well established
Website access
Archive access
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

4. Volcanic Ash Detection
Infrared image data from METEOSAT are processed to detect the presence of volcanic ash
Products could be:
GRIB or BUFR encoded for NWP community
Graphically represented (e.g. JPEG) for Volcanic Ash Advisory Centre (VAAC) or internet presentation
Described with a plain text bulletin or in XML
CAP can be used to encapsulate these formats
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

5. Volcanic Ash on EUMETCast
Style sheet reference
Graphics
CAP message
Text
CAP message contains standard information supplemented by hyperlinks to associated information
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

6. Sample web page containing a volcanic ash CAP message
Display is style sheet dependent
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

7. GEONETCast Overview EUMETCast Users FENGYUNCast Users EUMETCast
Network
Centre
FENGYUNCast
Network
Centre
Data exchange
EUMETCast
Data
Providers
FENGYUNCast
Data
Providers
GEONETCast
Americas
Network
Centre
GEONETCast
Americas
Data
Providers
GEONETCast
Americas
Users
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

8. GEONETCast Coverage
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

9. GEONETCast Alert Channel
GEONETCast Americas has an alert channel
EUMETCast is EUMETSAT’s component of GEONETCast
EUMETCast currently has a virtual alert channel (part of product channel)
In next couple of months dedicated EUMETCast alert channel will be enabled
EUMETSAT uses CAP for some of its own products. The MSG Fire Detection and Volcanic Ash products are created using CAP
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

10. Channel Based Dissemination
Each product/product category is assigned to a dedicated multicast channel on GEONETCast such as RA-VI BMD,
Training Channel, Info Channel, Data Channel 1-4 etc. … and “Alert Channel”
Each channel uses either a dedicated or shared bandwidth for dissemination
Priorities are assigned depending on delivery needs
User groups can be assigned to each channel (access control supported)
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

11. Dedicated Alert Channel
Dedicated bandwidth
Channel is kept free of any other data then alerts
Channel is setup for high priority and immediate dissemination
Data exchange to the partner GNCs
NRT availability of CAP alerts simultaneously on the entire footprint
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

12. GEONETCast Alert Channel
regular transmission of empty alerts in order to check the status of the channel
GEONETCast
Users
Reception
Station
Recognises incoming CAP alert file
Raises alert
Normal data
GEONETCast
Network Centre
ALERT
Provider
e.g. GISC,
DCPC, NC, Others
High priority NRT-
Dissemination of
CAP Alert Messages
CAP Alerts
Multicast NRT
Dissemination
GNC
Reference
Reception
Station
feedback of CAP alert reception for SLA monitoring
Portal
(Product Navigator)
High priority processing and NRT dissemination on dedicated channel
Data exchange
CAP Alert stored in WEB portal for Internet retrievals
Internet
Users
can discover and subscribe to CAP alerts
Partner
Network
Centre
On reception of a CAP alert the GNC decodes the alert to distinguish if the alert is for global exchange or regional
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

13. The Global Telecommunication System
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

14. Volcanic Ash on GTS
CAP message in XML is wrapped with routing information for the GTS. The wrapper is removed after transfer to the destination to restore the original message.
GTS wrapper
Style sheet reference
Style sheet reference
Style sheet reference
CAP message
CAP message
CAP message
EUMETSAT
NWP Centre
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

15. Wrapping of CAP for GTS
<?xml version = "1.0" encoding = "UTF-8"?>
<?xml-stylesheet type="text/xsl“ href="cap_alert_eum.xsl"?>
<alert xmlns = "urn:oasis:names:tc:emergency:cap:1.1">
<identifier>EUM.MET09.VASH.1</identifier>
...
</info>
</alert>
<SOH>\r\n\rnnn\r\r\n[ABH]\r\r\n
<?xml version = "1.0" encoding = "UTF-8"?>
<?xml-stylesheet type="text/xsl“ href="cap_alert_eum.xsl"?>
<alert xmlns = "urn:oasis:names:tc:emergency:cap:1.1">
<identifier>EUM.MET09.VASH.1</identifier>
...
</info>
</alert>
\r\r\n<ETX>
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

16. Abbreviated Bulletin Headers for CAP
ABHs have the form
For volcanic ash data in CAP, this could be:
T1 = X [Common Alerting Protocol (CAP)]
T2 = V [Volcanic ash clouds (SIGMET)] or O [Other]
A1A2 = NT [North Atlantic area, case dependent]
ii = 01 [Essential data as per WMO Resn. 40]
CCCC = EUMG [EUMETSAT/MSG]
YYGGgg = [date & time, case dependent]
Several choices of T1T2 have been considered, including WV, FX, WX, XW, XO and WO. It is important that the data are not confused for an existing product. The most recent suggestion, after consultation with, among others, ICAO is T1T2 = XO.
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011

17. Conclusion
The intrinsic standardisation of CAP ensures syntactic and semantic interoperability of the data
Dissemination of volcanic ash products using CAP on the GTS and via EUMETCast/GEONETCast allows one product to meet the requirements of different groups of users
CAP messages can supply the GTS community with information which can be understood and used in a variety of applications and disciplines
Common Alerting Protocol (CAP) Implementation Workshop
Geneva, Switzerland, 6-7 April 2011