General

As mentioned during IROWG-11, in addition to the general IROWG mailing list, several subgroup mailing lists have been created to facilitate communication within specific IROWG subgroups.

Currently, subgroup mailing lists are available for Climate, Innovation, NWP, and Space Weather. Each subgroup mailing list is managed independently from the general IROWG mailing list, and membership in one list does not automatically subscribe you to another.

The subgroup leads serve as the moderators of their respective mailing lists and will manage how each list is used to support communication within the subgroup.

If you participate in an IROWG subgroup, you are encouraged to subscribe to the relevant subgroup mailing list. Please visit https://lists.irowg.org to subscribe, manage your subscriptions, and access the mailing list archives.

Instructions for subscribing to and managing the mailing lists are available on the IROWG Mailing List webpage.

Thanks,

Hui

IROWG co-chair

Dear IROWG colleagues,

At the latest Coordination Group for Meteorological Satellites (CGMS) plenary meeting (June 2026), IROWG was notified that CGMS Working Group III (WGIII) tasked IROWG with coordinating a scientific assessment of the impact of the decline in COSMIC-2 radio occultation (RO) observations expected as the constellation ages. The IROWG assessment is to inform the next WGIII Risk Assessment Workshop (24–26 February 2027). FYI, IROWG is under CGMS-WGII (Satellite data and products), while WGIII is the Working Group on Operational Continuity and Contingency Planning.

The action reads:

WGIII has indicated that “we do not need IROWG to weigh in on the potential acquisitions strategies for data, but rather to provide information about what data is needed to maintain capabilities and/or mitigate loss of COSMIC-2.The purpose of the action is for IROWG to provide information to WGIII in advance of the next Risk Assessment to inform WGIII discussion/evaluation of risk posed by degradation/loss of COSMIC-2 and, if needed, discussion of potential contingencies to mitigate loss of COSMIC-2. The questions WGIII would like the IROWG to answer are:

1. >From a scientific perspective, what is the minimum number of equatorial (low inclination) RO needed to maintain current performance of operational NWP
2. Define what they mean by low inclination (clarify the orbital characteristics for low inclination so we can be sure we are all talking about the same thing)
3. Identify if there are options to use increases in the number of non-low inclination RO to mitigate the loss of COSMIC 2 and if so, to be specific about how many additional occultations (be specific about number and distribution needed). “

The IROWG Co-Chairs will meet with WGIII shortly after IROWG-11 (September 2026) to provide an update on the community’s progress. Therefore, we would like to begin gathering relevant information before the workshop and continue the discussion during IROWG-11.

We would greatly appreciate hearing from anyone who has:

• existing publications, reports, or presentations relevant to the impact of declining COSMIC-2 observations;
• ongoing studies or planned work related to this topic;
• operational or research experience that could help inform the scientific assessment.

We recognize that IROWG is an international scientific working group, and contributions are entirely voluntary. Existing analyses, ongoing work, and expert perspectives are all valuable.

If there is sufficient interest, the IROWG Co-Chairs would also be happy to organize an informal community discussion before IROWG-11 to exchange ideas and help facilitate discussion during the workshop.

If you have relevant material or would like to contribute to this assessment, please contact the IROWG Co-Chairs at your convenience.

Thank you in advance for your help and for supporting this community effort.

Best regards,

Hui Shao and Uli Foelsche, IROWG Co-Chairs

Tony Mannucci, IROWG Rapporteur

Please register for OPAC-IROWG 2026!

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Conference registration is open until July 31:
https://opacirowg2026.uni-graz.at/en/registration
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Remember: the registration includes lunch and dinner (except Sunday), Get-together party, drinks during the poster session, conference dinner, wine tasting (we don’t force you to drink wine – but it is included), …

Thanks to our sponsors:
https://opacirowg2026.uni-graz.at/en/sponsors/
we have been able to keep the registration fee in a reasonable range, and to reduce the fee for students to 250.- EUR

We are currently planning the detailed program, some key points are:

Wednesday, Sept. 9: arrival in Seggauberg, Dinner included
Thursday, Sept. 10: Workshop starts at 9:00.Get-together dinner in the evening.
Friday: Poster session (including drinks) in the evening.
Saturday: IROWG Subgroup-meetings, excursion and conference dinner.
Sunday is free – you can relax, or prepare your talk …
Monday: Guided wine cellar tour (incl. wine tasting)
Wednesday, Sept. 16: Workshop ends around noon, Lunch included

If there is urgent need for a side meeting (e.g. on the BUFR format …), this could happen on Tuesday evening.

Please check the workshop page for updates, e.g. regarding travel info:
https://opacirowg2026.uni-graz.at/en/info/

We are looking forward to seeing you in Austria in September!

Uli Foelsche, on behalf of the organizing committee.

U. Foelsche, J. Danzer, M. Schwärz, (WEGC & IPhys UniGraz, AT), OPAC Chairs
H. Shao (Naval Research Lab., USA), IROWG Co-Chair
A.J. Mannucci (JPL, Pasadena, USA), IROWG-CGMS Rapporteur