Multisensor Observations during the Flood Event of 4-6 November, 1994 over Northern Italy

In the perspective of flood hazard multisensor monitoring, the event of 4-6 November, 1994 over Northern Italy is described and analyzed in this paper using traditional ground-based rainfall observations and remote sensing techniques. Satellite imagery is used with different objectives: the interpretation of SAR measurements allows the identification of flooded areas, Meteosat infrared images show high intensity rain areas and SSM/I passive microwave data provide estimates of the rain-rates. The IFA-SAP algorithm, a profile based retrieval technique for estimating rainfall rates and precipitating cloud parameters from spaceborne multifrequency microwave radiometers, has been used in the latter case. The use of multisensor observations considerably supplements conventional monitoring systems which prove inadequate for many hydrological purposes. The present paper is written in the spirit of encouraging a posteriori analyses of observed heavy rainfall events so as to explore the potential of a real-time operational integrated system.