1. Upper-air observations for climate: Rationale, progress, and plans for the GCOS Reference Upper-Air Network (GRUAN) Dian Seidel, Howard Diamond, David Goodrich, NOAA Peter Thorne, Met Office AMS 25th Conference on International Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology --- J5.1 15 January 2009 – Phoenix, AZ

2. The who, what, where, when, why and how of GRUAN … in brief Related article to appear in March 2009 BAMS Contributions from many GRUAN colleagues Take home message: After more than a decade of discussion, a GCOS Reference Upper Air Network, to provide climate- quality measurements of tropospheric and lower stratospheric variables, is starting to become a reality.

3. What is GRUAN? An international reference observing network Designed to meet unmet climate requirements Measuring GCOS “Essential Climate Variables”

4. Why do we need GRUAN? Provide long-term, high quality upper-air climate records, with complete estimates of measurement error Fully characterize the properties of the atmospheric column and their changes Constrain and adjust data from more spatially comprehensive global observing systems (including satellites and current radiosonde networks) Ensure that potential gaps in satellite programs do not invalidate the long-term climate record

5. Why do we need GRUAN?

7. Who will steer, manage, and operate GRUAN?

8. Who … the org. chart Working Group on Atmospheric Reference Observation guides development of GRUAN recommends to AOPC site selection guidelines for observations, data diss. Chair: Peter Thorne GRUAN Lead Centre making GRUAN happen network management Head: Holger Vömel GCOS Secretariat support to ARO, AOPC, GCOS Steering Comm. connective tissue Director: Alexander Karpov GCOS Steering Committee Chair: John Zillman Atmospheric Observation Panel for Climate (AOPC) Chair: Adrian Simmons WMO GCOS co-sponsor Lead Centre designation

9. Who … key partners National contributors (incl. US) WCRP and the climate science community Other monitoring networks, e.g. – Network for the Detection of Atmospheric Composition Change – Baseline Surface Radiation Network Global Space-based Inter-Calibration System WMO - CIMO and CBS; Observations Department NMS international departments, development agencies

10. Where will GRUAN stations be?

11. What observations will be made at GRUAN sites?

12. How will GRUAN observations be archived, disseminated, and used? GRUAN Data Center – distributed functions – built on existing capabilities at DWD, NOAA, DOE Ensure the early, ongoing and widespread use of GRUAN observations. Focus efforts on – characterizing observational error – improving satellite data products – understanding climate variability and change.

13. When will GRUAN measurements end? Continue as long as there is a need for in situ reference atmospheric profile observations for climate Several decades, at least Until satellite (or other) observations can be independently and unambiguously calibrated to international standards

14. More questions? Check out www.gruan.org