Mark Smees, Catherine Gaffard, John Nash, (Met Office). GCOS/CIMO/WMO Training Workshop on GUAN Upper-Air-Observations for RA1 (Africa) Mark Smees, Catherine Gaffard, John Nash, (Met Office). Upper-Air team, Observations Research and Development, Met Office, UK The practical sessions consisted of: Demonstrations of HEMI radiosonde equipment Training using different HEMI radiosondes Demonstration of Hydrogen safety and balloon filling procedures Demonstration on selecting significant point for the TEMP message Procedures regarding balloons (storage, inflation and handling, attaching the radiosonde to the balloon, and releasing the balloon). Launching multi-rig radiosondes The practical was held at the Namibian Meteorological Service Headquarters in Windhoek. Participants preparing a multi-rig with 3 radiosondes, Modem, Vaisala, and InterMet. The launch area was quite small so great care was needed when launching rigs of this size. Participants practicing with the InterMet system, under the tuition of Andrew Spencer, InterMet Africa. During the practical there were 5 multi-rig ascents with various configurations of Modem, Vaisala and InterMet radiosondes. These multi-rigs were flown on both 350g and 1200g balloons. During the workshop is was shown that you could obtain a burst height at a pressure lower than 30hPa with good quality 350g balloons, and with the proper handling and storage. 30hPa is the minimum requirement for GCOS, and this is was not being achieved by many GUAN stations in Region 1. Met Office FitzRoy Road, Exeter, Devon, EX1 3PB United Kingdom Tel: 01392 885680 Fax: 01392 885681 Email: alec.bennett@metoffice.gov.uk © Crown copyright 2008 Met Office and the Met Office logo are registered trademarks