CERGOP II semi-annual progress report, april 2004 of the Italian space agency

The work packages in charge to ASI are: WP.l. Internet based seamless database for environmental studies; WP.3. Periodic determination of the reference frame CEGRN; WP.5. GPS data analysis and the definition of reference frames ; WP.6. Analysis of the long-term coordinate time series; WP.8. Impact of atmospheric effects on GPS height determination; WP.9. GPS based rapid service for meteorology and hazard assessment; We have the prime responsibility of the WP. 9. Our technical report concern just the activities on such WP and deals with the additional activities performed in the last 6 months.