Meeting‐07‐07‐2025 - wmo-im/et-w2it GitHub Wiki

2025-07-07-ET-W2IT meeting

ET-W2IT members

No Name Role Country Presence
1 Jeremy TANDY Co-Chair UK Yes
2 Youssef Darar Co-Chair Morocco No
3 Zeinab Zakeri member Iran No
4 David Podeur member France yes
5 Kentaro Tsuboi member, Japan no
6 Steve OLSON member USA Yes
7 Kai Thorsten Wirt member Germany Yes
8 Weiqing Qu member Australia No
9 Angelica Guterres member USA No
10 Tom Kralidis member Canada Yes
11 Jan OSUSKY member HMEI No
12 Wenjing Gu member China yes
13 Pavel Tsukanov member Russia No
14 Eiji  TOYODA Observer Japan Yes

Invited experts

No Name Role Organization Presence
1 Rémy GIRAUD SC-IMT Chair Météo-France Yes
2 Lei XUE SC-IMT Co-vice-chair CMA
3 Hyumin EOM GISC Seoul representative KMA Yes
4 Eiji Toyoda ET-W2IT observer JMA Yes
5 Kari Sheets GISC Washington representative NOAA Yes
6 José Mauro GISC Brasilia representative INMET Yes
7 Ping GUO GISC Beijing CMA Yes
8 Elena Arenskötter GISC Offenbach DWD Yes
9 Chems Eddine GISC Casablanca DGM Yes
10 Omar Mohammed Khalid GISC Jeddah NCM Yes

WMO Secretariat

  • Enrico Fucile
  • Hassan Haddouch
  • Xiaoxia Chen
  • David Inglis Berry
  • Peiwen

Agenda

  • Item B: Implementation of Global Replay Services (Tom Kralidis)

If time permits, we will also address the following items:

  • Item F: Metadata Management and Catalogue Synchronization
  • Item Q: Readiness for Metadata Validation

1- Implementation of Global Replay Services (Tom Kralidis)

Jeremy presented the steps agreed upon at the last meeting:

  • Step 1: Endorse the specification (PR: link)
    • Step 1A: Canada and South Korea are offering services on a pre-operational basis
    • Step 1B: encourage Members to use the pre-operational Global Replay Service particularly ECMWF and other NWP centres and provide feedback
    • Step 1C: Amend documentation / Specification if necessary
    • Step 1D: INFCOM-4 endorsement

Specifications and documentation:

Adding GRep to the WIS2 Guide PR144. pending W2IT review and approval.
Related items:

Presentation Summary (Tom Kralidis):

Tom presented the WIS2 Global Replay Service (WIS GRep). In his presentation, he covered the following key points:

  • Requirement for a Global Replay Service (GRep)
  • Component definition
  • Technical considerations
  • Reference Implementation

the presentation is available here GRep

Discussion:

A discussion was raised regarding the format and requirements of the subscriber-id.

  • Kai raised a question about the possibility of using the centre ID as the subscriber identifier.
  • In response, Jeremy recommended using a UUID (Universally Unique Identifier) to ensure global uniqueness and to avoid potential conflicts. He explained that while any identifier could technically work, it is critical that the subscriber-id be guaranteed to be unique, especially in distributed systems like WIS2 where multiple clients may be interacting with brokers simultaneously. If two entities were to inadvertently use the same subscriber-id, it could result in unexpected behavior or data delivery issues. Therefore, adopting a UUID format is strongly encouraged as a reliable method to safeguard uniqueness and system stability.

It was agreed that subscriber-id defined by user/client (callback):

  • SHALL be a UUID
  • MAY be reused

In response to a question from David Podeur, Tom clarified that the Global Replay Service (GRep) is currently subscribed only to the Global Broker in France. However, he confirmed that it will be configured to subscribe to all Global Brokers, and a deduplication mechanism using WNM, will be implemented to manage duplicate messages.

GB Subscription topics are as follows:

  • origin/a/wis2/#
  • cache/a/wis2/#
  • monitor/a/wis2/#

Regarding the update of the manual, it was agreed to check the approval process to decide
Action: Hassan to check the approval process and inform Remy, Jeremy and TOM after the meeting
Decision: The meeting agreed that Tom, Remy, and Jeremy will review and approve the pull request (PR).

2- F: Metadata Management and Catalogue Synchronization

Jeremy raised concerns regarding metadata management and highlighted the following key points:

  • Different contents in GDCs: https://jira.wmo.int/browse/WI-55 (not updated since 13 June);
  • outdated topics in use, outdated metadata, identifiers, and a lack of consistency.
  • Canada is working with Germany to synchronize WCMP2 records in the three GDCs completed, and is currently collaborating with China on the same task (in progress)

Requirements:

  • All the Global Discovery Catalogues must provide a consistent set of WCMP2 records. in response to a question related to what does "a consistent set of WCMP2 records" mean, and how is this objectively assessed, it was proposed the following:
  • ET-W2IT define the KPI for consistent WCMP2 records at GDCs
  • GDC operators individually determine how to meet the KPIs
  • ET-WISOP will use the normal workflow to resolve JIRA tickets,
    regarding the issue about old WCMP2 records removed from cma-GDC it was reported that:
  • Tom cleaned up the WCMP2 collection and published an archive object
  • Kai/Elena restored DWD GDC from the clean archive
  • Xinqing restored CMA GDC from the clean archive

regarding the request that all the Global Discovery Catalogues must provide a consistent set of WCMP2 records, it was reported the following:

  • Canada and DWD use the same software
  • China uses pywcmp2 but developed complementary components.
    regarding the question what does "a consistent set of WCMP2 records" mean? it was agreed the following:
  • routine GitHub action to merge list of knowen records(metadata-id) from each GDC into a single list
  • This list will be used by the GB to determine if metadata exists
  • The merged list will be first from Canada and DWD. China will be added after a clean-up create a sensor centre that compares the 3 GDCs doing their daily archive:
    • check the archive is published each day
    • check consistency
    • publish WMEM to report issues, including "everything fine" message.
    • define metrics for the sensor centre

Actions :

  • Tom to update the JIRA ticket. and close issue 4
  • Remy and Tom to develop specs and define metrics for the sensor centre by the end of August
  • Tom, implementation of Sensor Centre deployed by the end of September
  • Jeremy to pull together list of Sensor centre concepts; and will cordinate with Kai to capitalize on what have been discussed previously in the Gateway's test preparation meeting (e.g WIS2-GTS comparison done by Chems and the GC comparison by Remy)

Decision:

The meeting concluded with agreement that Tom, Remy, and Jeremy will review and approve the pull request (PR).