TDR soil moisture measurements at the Lago Maggiore MAP target area: preliminary results

Abstract

Surface moisture was measured at selected sites in the Lago Maggiore (Italy) target area before and during Mesoscale Alpine Programme (MAP) Special Observing Period (SOP). Additional soil moisture measurements were performed contemporaneously with remotely sensed microwave measurements carried out by another MAP team. The soil moisture conditions influence the runoff produced during heavy precipitation events but long records of soil moisture measurements, like that presented here, are difficult to obtain. This data set, available at MAP Data Center, may be useful to improve real time flood forecasting and Numerical Weather Prediction models. The Osservatorio Geofisico (University of Modena and Reggio Emilia) team collected volumetric water content measurements by the Time Domain Reflectometry (TDR) technique. The TDR system was equipped with a multiplexer so that 14 buriable probes, installed at different depths, were automatically scanned at four hour time intervals and the daily soil moisture profiles were recorded. The data have been collected from the end of March 1999 up to the end of MAP-SOP (November 15, 1999). During this period, the first 70 cm of soil were monitored; the minimum of the soil moisture was 17.7 %; the maximum of the soil moisture was 56.0 %. The data allow also investigation of the soil behaviour after heavy precipitation events (e.g. the one happened during the MAP Intensive Observation Period (IOP) 02) depending on its moisture condition before the precipitation. Finally, from the soil water content profile, the cumulative evaporation is computed on the basis of a mass balance, when drainage is supposed to be ceased and no horizontal flux is present.