Adrian Simmons, AOPC Chair WOAP-II, JRC Ispra, Italy

1. Summary of GCOS AOPC annual meeting (April 2006) and ongoing activities Adrian Simmons, AOPC Chair WOAP-II, JRC Ispra, Italy

2. The April session of AOPC was the: • last under leadership of Mike Manton • first attended by new chair of AOPC • first attended by new chair of GCOS Steering Committee • Examined operation of GCOS surface and upper-air networks • issuing appropriate acknowledgements • recommending or supporting many actions aimed at improvements • Reviewed work towards establishment of a network of reference upper-air observing sites, and established a working group to assist towards this end • Membership and TOR of WG have subsequently been finalized • AOPC Chair and GCOS Director have liaised with WG chair (Peter Thorne) over this and the Report following Seattle Workshop

3. Reviewed draft of the document “Systematic Observation Requirements for Space-based Products for Climate” providing supplemental details to the satellite-based component of the GCOS Implementation Plan • preparation of which has involved AOPC chairs past and present, among others • Commended and recommended a number of specific developments in satellite observation and data processing • welcoming, in particular, the plan for the WMO/CGMS Global Space-based Inter-Calibration System (GSICS) • Considered observations of atmospheric composition • expressing concern about the current lack of provision for follow-on satellite missions that would maintain the emerging capability for monitoring tropospheric air quality from space provided by satellites such as AURA and ENVISAT • reviewing matters relating to the GAW networks for measurement of carbon dioxide, methane and ozone

4. Discussed observational issues related to climate-forcing • drawing conclusions (with input from Bill Rossow) on strategies for monitoring radiation and related atmospheric variables, as reflected also in Satellite Requirements supplement to the GCOS Implementation Plan • requesting the GCOS Secretariat to assist the WCRP secretariat in resolving uncertainties in arrangements for the archive of BSRN data • Reviewed joint AOPC/TOPC issues • welcoming participation and presentation of Michel Verstraete from TOPC • proposing such participation from TOPC continue in future • establishing a joint Working Group on Land-Surface/Atmosphere Issues to promote the coherent retrieval of surface and atmospheric ECV products • Reviewed joint AOPC/OOPC issues • expressing appreciation of progress with oceanographic observation but concern at prevalence of research rather than operational funding • welcoming new Co-chairs of joint Working Group on SST and Sea Ice • requesting the Chair of the joint Working Group on Surface Pressure to review TOR and membership in consultation with the AOPC Chair

5. Discussed precipitation products • appreciating work of GPCC • noting and recommending further study of issues related to high latitudes • requesting TOPC to promote investigation of the apparently-changing relationship between precipitation and runoff, especially at high latitudes • Considered status of reanalysis • welcoming the progress that has been achieved and the activities that are planned in Europe, Japan and the USA • requesting incoming AOPC Chair to liaise with WOAP to prepare a paper on the value of continuing investment in reanalysis, including development of an internationally-shared database • Encouraged Mike Manton (in collaboration with Panel Chairs) to prepare a paper outlining the justification and benefits of a small set of global climate indicators • Recognised the importance of reviewing the status of actions from the GCOS Implementation Plan at its future sessions