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Dear colleagues,
We cordially invite you to participate in the 3rd meeting on the GEWEX water vapor assessment (G-VAP).

The meeting will take place at the Cooperative Institute for Research in the Atmosphere (CIRA), Colorado State University, Fort Collins, USA, on 30 September until 02 October 2013. The meeting will start at 09:00 local time on 30 September and will end at 12:00 local time on 02 October. The drafting of the agenda is organized by DWD and NOAA/NCDC. The agenda will be distributed in an upcoming circular.

The GEWEX Data and Assessments Panel (GDAP) has initiated G-VAP intended to quantify the current state of the art in water vapour data records being constructed for climate applications and by this support the selection process of suitable water vapour products by GDAP for its production of globally consistent water and energy cycle products. G-VAP activities started in 2011. Since then two workshops have been conducted and the summaries have been published in the GEWEX News*. More information on G-VAP is available on
The main objectives of the 3rd meeting are to

  • Present and discuss results achieved thus far,
  • Refine on-going activities with the main objective to find explanations for observed discrepancies and limitations in long-term satellite data records,
  • Discuss new activities and new contributions related to existing activities,
  • Discuss the structure of G-VAP report.

Please register for the G-VAP meeting by sending an email to and and provide relevant information, that is, your name and affiliation. It is foreseen to have invited presentations only. Nevertheless, you may submit abstracts as well. We kindly ask you to register prior to the 31 July 2013.

With the registration, you may also inform us on where you stay and if you will have a car or if you need transportation. We might be able to support local transportation.

Participants are expected to cover their own expenses to attend the meeting.
We look forward to your active participation in this important international activity under the framework of WCRP-GEWEX.

Yours sincerely,
Marc Schröder and Lei Shi

Monday, 30th Sep 2013

09:00 – 09:15 Welcome

09:15 – 09:30 Aims of meeting and logistics
Schröder, Shi, Divico

09:30 – 10:30 (15 minutes each)
Continuous water vapour observations at ARM sites
IASI retrieval and evaluation activities at EUMETSAT
NASA Water Vapor Project-MEaSUREs (NVAP-M) global water vapor dataset: Early results for climate studies
Vonder Haar, Forsythe

10:30 – 11:00 Coffee break

11:00 – 11:15 Trend comparison between GNSS and satellite microwave observations

11:15 – 11:30 Regional trends in precipitable water vapour

11:30 – 11:45 ESA’s MWR project

11:45 – 12:15 An introduction to the GEWEX products

12:30 – 14:00 Lunch break

14:00 – 14:30 GEWEX water vapour and temperature profiles

14:30 – 15:00 G-VAP plan, web and data fact sheet

15:00 – 15:30 Water vapour and profile validation using NPROVS/GPROVS
Reale, Gambacorta

15:30 – 16:00 IASI/AIRS validation using radiosondes
15:30 – 16:00 Coffee break

16:00 – 17:30 (15 minutes each)
First results from inter-comparison
Assessing homogeneity
Trends in TCWV and theoretical expectation
First Level2 evaluation

17:30 Adjourn


Tuesday, 1st Oct 2013

09:00 – 10:30 (15 minutes each)
UTH inter-comparison
Shi, Yang
Correlation of UTH data records to climate indices
Shi, John
Trends in UTH
Latest results from GPS-RO

10:30 – 11:00 Coffee break

11:00 – 12:30 Introduction to discussion on how to assess homogeneity and stability
Group discussion
Moderator: Bennartz; Rapporteur: Lindstrot

12:30 – 14:00 Lunch break

14:00 – 14:30 Summary of group discussion

14:30 – 15:30 Introduction to discussion on how to find reasons for distinct differences in space and time
Group discussion
Moderator: Gambacorta; Rapporteur: Lockhoff

15:30 – 16:00 Coffee break

16:00 – 17:00 Group discussion continued

17:00 Adjourn


Wednesday, 2nd Oct 2013

08:30 – 09:00 Summary of group discussion

09:00 – 09:30 An introduction to SPARC water vapour II
Rosenlof (tbc)

09:30 – 10:30 Introduction to discussion on SPARC/G-VAP cooperation
Group discussion
Moderator: Rosenlof (tbc); Rapporteur: Schröder

10:30 – 11:00 Coffee break

11:00 – 11:30 Summary of group discussion

11:30 – 12:00 Wrap-up, next meeting

12:00 – 12.30 AoB

12:30 Expected end

Workshop Organizers

Marc Schröder

Lei Shi

Local Contacts

Chris Kummerow

Joanne DiVico

Holli Knutson