1. Implementation of CAP in Hong Kong Observatory
TONG Yu-fai
Scientific Officer
Hong Kong Observatory (HKO) Hong Kong, China
Common Alerting Protocol (CAP) Implementation Workshop
WMO Headquarters, Geneva, Switzerland, 23 – 24 April 2013

2. Hong Kong Observatory (HKO)
A government department of Hong Kong
Responsible for forecasting weather and issuing warnings on weather-related hazards in HK
Monitor and assess radiation levels in HK, and provide geophysical services

3. Weather Warnings Landslip warning
Hong Kong Observatory (HKO) is the alerting authority in Hong Kong to issue the following weather warnings:
Special Announcement on Flooding
Landslip warning
Tropical Cyclone Warning Signals (number-coded)
Strong Monsoon Signal
Fire Danger Warning
Rainstorm Warning Signals
(colour-coded)
Very Hot Weather Warning
Cold Weather Warning
Thunderstorm Warning
Frost Warning

4. Dissemination of Weather Warnings
Internet Website
eXtensible Markup
Language (XML)
Mobile applications
Telephone enquiry system
Public
Mass media (newspaper, radio
and television)
Social Network
Twitter/Weibo
SMS
Delivery via diverse and multiple means to communicate weather information of different volumes and degrees of details

5. Delivery of Warning Messages in XML format
Currently, HKO disseminates weather warning messages in its own XML-based format to users with the needs of system automation, facilitating exchange of weather warnings between machines.
Common Alerting Protocol (CAP) is a XML-based data format for exchanging warning messages.
Why do HKO need to deliver weather warnings in CAP - another XML-based format?

6. HKO’s XML data service
Provision of weather bulletins (including warnings ) in XML since 2003
A website was set up to allow users to retrieve the XML bulletins over the Internet

7. HKO’s XML data service Wide spectrum of users
Weather Info
in XML
Media
Transport operators
Utilities
Telecom
Service Industry
Government users
Wide spectrum of users
Effective means to deliver up-to-the-minute weather reports/forecasts and warning electronically

8. Limitations of the HKO’s XML Service for Delivery of Weather Warnings
“Proprietary” XML Schema
The schema specifying the HKO’s XML bulletins is proprietary, not adopted from any open data standard
No open library support. Users have to develop their tools to retrieve the HKO’s XML bulletins and ingest them into their systems.
Could not contain reference to additional information in the form of a digital asset
No geographic information. Messages target to all people in HK even though the incident affects only a specific area.

9. Limitations of the HKO’s XML Service for Delivery of Weather Warnings
Multiple message on same incident
For certain weather warnings, multiple XML bulletins referring to the same incident are issued to users, but containing different aspects of the information about the incident.
Tropical Cyclone Warning Signal
TC bulletin (TC analysis info)
TC signal bulletin (which TC signal is issued)
TC warning announcement (event description & actions to be taken)
Multiple messages for same event may cause user confusion and incur extra effort on users to incorporate the XML bulletins into their information systems.

10. Why do HKO need to deliver weather warnings in CAP?
CAP is an XML-based data format for exchanging public warnings. It has advantages over the HKO’s XML data service:
CAP data format
HKO’s XML data format
Open data standard for exchanging public warnings  
Geographic information of target area
Reference to additional information (e.g. image/audio files)

11. Implementation of CAP for Local Weather Warnings
Combine messages of same event into a single CAP message
Example: TC warning signal
TC warning bulletin (which TC signal is issued)
CAP
TC analysis & forecast track information
Tropical Cyclone Warning Signal
TC warning announcement (event description & actions to be taken)
Combine them into a signal CAP message
These messages are originally coded in 3 different XML bulletins

12. Implementation of CAP for Local Weather Warnings
Combine messages of same event into a single CAP message
Example: TC warning signal
CAP message for TC warning
TC warning bulletin (which TC signal is issued)
<headline>TC No. 3 is issued at XX:XX HKT</headline>
TC warning announcement (event description & actions to be taken)
<description>…</description>
<instruction>…</instruction>
<parameter>
[analysis/forecast positions & intensities]
</parameter>
TC analysis & forecast track information

13. Challenge of Applying CAP for
Weather Warnings in HK
Certain CAP elements could not be directly determined by HKO’s warning messages
CAP element
Values allowed by CAP
Warnings issued by HKO
Urgency
Immediate, Expected, Future, Past, Unknown
Either Immediate or Expected
Severity
Extreme, Severe, Moderate, Minor, Unknown
Rainstorms: Amber/Red/Black
TC warning: Number-coded system
Fire danger warning: Yellow/Red
Certainty
Observed, Likely, Possible, Unlikely, Unknown
Either Observed or Likely

14. Option 1
Develop rules to assign values of CAP <severity> for each type of weather warnings.
Rainstorm Warning Signals
CAP <severity>:
Extreme,
Severe,
Moderate, Minor
30 mm/hr ?
50 mm/hr
70 mm/hr
As HK people already get used of the number- and colour-coded warning systems, the selection of CAP <severity> values must match their perception on the severity of local weather warnings.
The warning types (e.g. amber/red/black for rainstorms ) will be coded in the <eventCode> element.

15. Option 2
Extend the value domain of the CAP <severity> element to include the HKO’s number- & colour-coded warning systems
However, it would NOT conform to the XML Schema of CAP!

16. Tropical Cyclone Advisory of
Hong Kong Observatory
Tropical cyclone over the South China Sea could pose a threat to mariners and ships at sea over the region
HKO issues TC warning advisories to ships when a tropical cyclone is located with the area 10o to 30o N and 105o to 125o E HK
TC Warning Area of Hong Kong

17. Tropical Cyclone Advisory of
Hong Kong Observatory
Contain information about TC analysis and position/intensity forecast up to 72-hour ahead
Update every 3 hours
Broadcast to ships via NAVTEX (a radio frequency broadcast system, receiving by means of direct-printing telegraphy)

18. Benefits of Applying CAP for TC Advisories
CAP is a standard for delivering alerts and notifications
WMO endorsed standard
Messages could be delivered timely for disaster prevention and mitigation
CAP supports geographic information. Messages could be delivered to people who need them, and only those who need them
In adopting the CAP standard, multiple alert system could be activated with single input
With a standard, it benefits users because applications, e.g. WMO Severe Weather Information Centre (SWIC), could be developed to meet individual needs.

19. TC Advisories: Event focusing
TC advisories are originally targeted for NMHSs. Nowadays, they are put on the websites and many users are already making reference on it. A large amount of users of the TC advisories are the general public.
T+0
TC Advisories are focusing on the event, moving from one place to another
To whom should the alert be sent? Who are the users?
For TC advisories, defining an area for sending alert is not as straight-forward as other warnings

20. Provide alert / notification for the presence of TC of a particular strength
Break the TC advisory into different time intervals, e.g. 0-24, 24-48, 48-72, etc.
Alert area would be the polygon bounding the initial and final positions of the TC including the uncertainty circles
Provide alerts for the strongest intensity
Forecast discussions in TC advisory could be put in <Description> element
Forecast track could be encoded in other XML format, e.g. CXML, KML, etc. and attach to the CAP in the <resource> element

21. Provide alert / notification for the presence of TC of a particular strength
Area (24<T<=48)
Area (0<T<=24)

22. Next Steps …
Develop rules and automatic system to convert all local warnings & TC advisories into CAP format
Set up a dedicate website to publish the CAP warnings and feeds
Develop public outreach and promulgate users (media, public utilities, transport operators, etc) to make use of CAP in their information systems

23. Thank You