A time varying rain field generator

This paper proposes a technique to generate time varying rain rate fields over large areas which needs as input the forecast of the total cumulated rain over the area of interest. The technique is based on the quasi-ergodicity property of the rain field that has been tested by working out very many radar maps of precipitation collected in the Padana Valley by the S band Doppler meteorological radar sited at Spino d’Adda. The generator takes into account the period of the year the estimate has to refer to, by modelling first the yearly P(R) with an appropriate analytical function and then by identifying the yearly modulation of the function parameters.