1. WE-06-01 Surface-based Global Observing System for Weather

2. OBJECTIVES Achieve a complete and stable surface- based (in-situ and airborne, land and possibly ocean) Global Observing System (GOS). High priority should be given to a stable, and as much as possible automated, fully functional World Weather Watch Upper Air Network and the further development of the Aircraft Meteorological Data Relay (AMDAR) programme.

3. STATUS The Expert Team,at its session in May 2008, updated Automatic Weather Systems (AWS)Functional Specifications, prepared draft requirements for a robust AWS suitable for all locations, prepared draft requirement for AWS to contribute fo the calibration of ground truth of space-based observations, draft requirements for new sensors or integration of sensors to overcome deficences of AWS following the migration from manual observations and developed a draft guidelines to assist in the transition from manual to automatic surface observing stations. The ET, in collaboration with Meteo France, is preparing a classification scheme applicable for the surface in-situ observing stations, and in collaboration with KNMI, the method suitable for optimization of RBSN/RBCN networks.

4. Aircraft Measurements AMDAR The AMDAR Panel is working in collaboration with manufactures of water vapour sensor to improve the performance of the water vapour sensor technology for AMDAR. The first Ad-Hoc Steering Group meeting of the WIGOS Pilot Project for AMDAR, Geneva, July 2008 developed a strategy for enhancing the delivery of aeronautical data from AMDAR platforms to users. The AMDAR Pilot Project will focus on the practices impacting AMDAR data collection, processing, archiving and dissemination. In addition new methods and procedures will be generated in preparation for the deployment of new operational instruments, such water vapour sensors.

5. Marine Observations Members are invited to enhance their participation in the ASAP programme for providing in situ aerological profiles from ocean data sparse areas as complementary data to AMDAR. JCOMM engaged in a WIGOS Pilot Project in close cooperation with the oceanographic community and IOC. The Pilot Project is promoting the development of interoperability arrangements between the ocean data systems and the WIS; the integration of Best Practices and standards in cooperation with IMOP, including the possible development of ocean instrument centres; as well as the development of standard quality management systems (e.g. ISO compliant).

6. Instruments Intercomparison The WMO Field Intercomparison of Rainfall Intensity Instruments in Vigna di Valle (Italy) continues. The meeting of participating manufacturers was held in May 2008 to fix problems occurred. The coordination activities are going on as regards the data analysis and quality control. The forthcoming meeting of ET/IOC in September will consider the status of the Intercomparison and decide on possible extension of the Intercomparison for one more year. The inspection of the WMO Field Intercomparison of Thermometer Screens/Shields and Humidity Measuring Instruments in Ghardaïa (Algeria) was conducted in June by the expert from Meteo-France. Field calibration of the instruments was performed during the visit. Meteo-France collaborates closely with NMS of Algeria regarding further management of the Intercomparison.

7. Intercomparisons con’t The CIMO ET/IOC UASI at its session in June 2008 considered the results of several recent international and national radiosondes tests due to changes in radiosondes design, progress in the further development of other upper-air measurement systems and related planned projects. In this context, the ET/IOC considered the requirements for future tests/intercomparisons of upper-air systems, GRUAN included, with the main focus on the 8th WMO Intercomparison of radiosonde Systems, China, 2010.