Atmosphere analysis

A detailed knowledge of the atmosphere conditions is mandatory to increase the SRT performances at higher frequencies. For such a reason the highly variable weather-climate parameters that may affect the observation quality and the pointing capability are constantly monitored at the site. Ground-based measurements of brightness temperature, opacity, vapor and liquid content, wind speed are performed in real-time and may be easily accessed by graphic interfaces. Furthermore we are testing a state-of-the-art numerical weather prediction model. The model is able to predict (48 hours in advance or more) the radiometric conditions at the antenna site making feasible a dynamic scheduling approach for SRT. Briefly, in winter time there is a 40 - 45% probability of finding integrated water vapor lower than 10 mm. The absence of cloud cover can be found 50% of the time in winter and 80% during summer, typical liquid water values range between 0.2 and 0.7 mm. During winter time the opacity at 22 GHz is lower than 0.15 Np for 90% of the time and 40% during summer. At higher frequencies, in the 3-mm band, the winter opacity is lower than 0.15 Np for 35% of the time.