This letter is in response to the recent NRC letter report GEWEX-CLIVAR: Coordination of U.S. Activities. I write as chair of the CLIVAR Interagency Group, a panel of agency program managers who are supporting the U.S. contribution to CLIVAR and who are sponsoring the CLIVAR Science Steering Committee. The NRC interest in this issue and the summary of NRC recommendations in one brief volume is much appreciated.

The matter of interactions between these two WCRP programs has been the subject of much discussion within the Interagency Group and by the CLIVAR SSC. Participation in the upcoming GEWEX Panel meeting and devotion of roughly half of the May CLIVAR SSC to coordination with GEWEX is some evidence of the importance of this issue to the CLIVAR community. Russ Davis, co-chair of the CLIVAR SSC, will be attending the GEWEX Panel meeting and will describe more fully the scientific issues and organization of U.S. CLIVAR.

Your report was written prior to the December International CLIVAR Conference in Paris, and many of the issues are described in the attached U.S. CLIVAR Position Paper prepared for the conference. Several areas of potential collaboration deserve highlighting:

• The letter report recommends the coordination of GOALS [CLIVAR] process studies with those of GEWEX. The position paper cites a strong U.S. CLIVAR interest in expansion of studies concerning the American monsoon. The development of a new GEWEX American Prediction Project, focused on the Southwest, and CLIVAR interest in extension of American monsoon studies to the Pacific cold tongue and stratus region, appear to be fruitful areas for collaborative efforts. The position paper states: "Consideration of the role of land-surface processes and orography on the climate variability associated with the American monsoon will be included and would most appropriately be incorporated by partnership with GEWEX."
• From the U.S. CLIVAR perspective, extending ENSO studies to the Asian-Australian monsoon has a high level of interest; however, its current status in the U.S. from the programmatic point of view is less well-developed than the American monsoon. Interactions and collaboration with the GEWEX Asian Monsoon Experiment (GAME) community is expected to enhance understanding of the relative importance of ocean versus land heating in the interannual variability of the Asian-Australian monsoon.
• Potential CLIVAR participation in the Coordinated Enhanced Observing Period (CEOP) has been discussed at the last CLIVAR SSC meeting. CLIVAR expects to have considerable in situ observational deployments during the 2001–2002 period, and the use of the resulting data sets with those from new satellite measurements and from GEWEX hydrometeorology projects could result in unprecedented global climate data sets. However, definition of scientific goals and resolution of formidable data assimilation questions remain as issues.

A particular topic of discussion regarding CLIVAR-GEWEX coordination is the development and location of a U.S. GEWEX Project Office, and whether it should be co-located with a U.S. CLIVAR Project Office. At the moment, it appears likely that the latter will be located here in Washington, in the same building as our USGCRP Office.

Advantages of co-locating a U.S. GEWEX Office here are cited in your NRC report: ensuring that advances in one program feed into the other; minimizing duplication of effort; and promoting the most efficient mechanisms for progress.

However, interagency discussions cited significant disadvantages as well. A Washington location would not have the close ties to the academic community that a university-based project office might have. And, while co-location with CLIVAR might enhance coordination, the perception of CLIVAR activities coming to dominate GEWEX planning was cited as a potential drawback. It would be useful for agencies to get a sense of the views of the GEWEX Panel on this issue. In the meantime, development of a CLIVAR Office will allow room for potential expansion of a GEWEX Office, so as not to foreclose any options.

We look forward to working with you and with the GEWEX community, and anticipate productive discussions at the GEWEX Panel Meeting in Irvine.