The Feasibility of Forecasting Cirrus cloud Cover and Water Vapor Above Telescope Sites in northern Chile

摘要

This paper presents the results of a study conducted to examine the feasibility of forecasting cirrus cloud cover and atmospheric water vapor at European Southern Observatory (ESO) telescope sites in Chile at Paranal and La Silla. 6.7 mum imagery from the Meteosat-3 satellite was used to quantify water vapor and cirrus cloud cover conditions above the sites. Using these data in conjunction with upper-air meteorological data, a method was developed to forecast the amount and type of cirrus cloud cover and water vapor above the telescopes. Forecasts were made of moisture and cloud parameters for four periods in 1993 and 1994 and evaluated by an objective comparison of forecasted and measured values. The results clearly indicate that it is feasible to forecast water vapor and cirrus cloud conditions above Paranal and La Silla with an accuracy that would be useful for telescope scheduling.