The application of Satellite and Global Meteorological Model data to monitoring and forecasting of Moisture and Cloud at remote Sites in Northern Chile

The Southern Hemisphere is characterised by a paucity of meteorological data. Satellites provide the only means for continuous monitoring of atmospheric conditions at remote locations and over isolated areas. From 6.7µm satellite imagery it is possible to quantify moisture and cirrus cloud cover and, when synthesised with global meteorological forecast model data, forecasts of selected atmospheric moisture and cirrus cloud cover parameters can be made.

This paper presents the results of two feasibility studies conducted to determine if satellite and meteorological forecast model data could be combined to produce forecasts of water vapour and cirrus cloud cover at two remote sites in Northern Chile where some of the world's largest and most technologically advanced astronomical telescopes are operated. The studies, which employed Meteosat-3 weather satellite data at 6.7µm and numerical meteorological forecast model data from the European Centre for Medium-Range Weather Forecasting (ECMWF), show that forecasts of cirrus cloud cover and water vapour parameters above European Southern Observatories (ESO) telescope sites at Paranal and La Silla can indeed be made with an accuracy suitable for use in telescope scheduling.

Since the successful completion of the feasibility studies, steps have been taken to produce operational forecasts automatically using real-time GOES-8 satellite and ECMWF model data. This goal was achieved in August 1998 and the results of recent tests of the operational forecast system are also presented in this paper.