Hydrological response to radar rainfall maps through a distributed model

ABSTRACT

Weather radars in investigating physical characteristics of precipitation are becoming essential instruments in the field short term metereological investigation and forecasting. To analyze the radar signal impact in hydrological forecasting , precipitation input fields, generated through a statistical mathematical model, are supplied to a distributed hydrological model. Such a model would allow the control of the basin response to precipitation measurements obtained by a metereological radar and, in the meanwhile, to evaluate the influence of distributed input. The distributed model describes the basin hydrological behavior, subdividing it into distinct geometrical cells and increaisng the physical significance by reproducing the distributed hydrographic basins characteristics, such as infiltration capacity, runoff concentration time, network propagation speed, soil moisture influence. Each basincell is characterized by its geological, pedological and morphological status, and may be considered a unitary hydrological system, linked to the others by geomorphological and hydraulic relationships. To evaluate the dynamics of the flood event a synthetic representation of the channel network is introduced, where each stream branch is modeledas a linear reservoir. Finally, the discharge in the outlet section is derived, taking into account the hydraulic characteristics of the upstream branches.(AU)