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

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

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

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

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