Annual hourly variability of rain attenuation and rainfall rate for improved earth-space links design

The Earth-Space links availability is compromised due to gases, clouds, atmospheric turbulence and rain. Among the several types of induced attenuation, the rain-induced attenuation is of utmost importance for the design and evaluation of links operating at frequency-bands higher than 10 GHz. This attenuation is traditionally compensated by considering a long-term average attenuation margin, defined accordingly to the required service availability. On the other hand, the rain rate and the rain-induced attenuation present an hourly variability that can compromise the link availability, reducing the quality-of-service as perceived by costumers in the case of satellite services, increasing the time for the delivery of imagery in Earth observation services and postponing the download of space exploration missions' data. In this contribution the hourly variability of rain rate and rain-induced attenuation are characterized, both on a long-term longitudinal basis and on a transversal one, from one year to another.