176e560fc40f9776f8eeadd156496214.ppt
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The GEONETCast Alert Channel and CAP over GTS Simon Elliott EUMETSAT simon. elliott@eumetsat. int Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011
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 - net. CDF - HDF Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011
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
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
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
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
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 Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011 GEONETCast Americas Users
GEONETCast Coverage Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011
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
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
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
GEONETCast Alert Channel - regular transmission of empty alerts in order to check the status of the channel Normal data ALERT Provider CAP Alerts GEONETCast Network Centre Multicast NRT Dissemination Portal (Product Navigator) e. g. GISC, DCPC, NC, Others Data exchange Partner Network Centre -High priority processing and NRT dissemination on dedicated channel -CAP Alert stored in WEB portal for Internet retrievals -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 High priority NRTDissemination of CAP Alert Messages GEONETCast Users Reception Station -Recognises incoming CAP alert file -Raises alert GNC Reference Reception Station - feedback of CAP alert reception for SLA monitoring Internet Users - can discover and subscribe to CAP alerts
The Global Telecommunication System Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011
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 CAP message EUMETSAT Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011 NWP Centre
Wrapping of CAP for GTS xml version = "1. 0" encoding = "UTF-8"? > xml-stylesheet type="text/xsl“ href="cap_alert_eum. xsl"? >
Abbreviated Bulletin Headers for CAP ABHs have the form For volcanic ash data in CAP, this could be: T 1 = X [Common Alerting Protocol (CAP)] T 2 = V [Volcanic ash clouds (SIGMET)] or O [Other] A 1 A 2 = NT [North Atlantic area, case dependent] ii = 01 [Essential data as per WMO Resn. 40] CCCC = EUMG [EUMETSAT/MSG] YYGGgg = 091345 [date & time, case dependent] Several choices of T 1 T 2 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 T 1 T 2 = XO. Common Alerting Protocol (CAP) Implementation Workshop Geneva, Switzerland, 6 -7 April 2011
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