Assimilating X- and S-band Radar Data for a Heavy Precipitation Event in Italy

• DOI: 10.20944/preprints202106.0141.v1
• Publication Date: 2021-06-07T07:12:18Z
• Authors: Valerio Capecchi; Andrea Antonini; Riccardo Benedetti; Luca Fibbi; Samantha Melani; Luca Rovai; Antonio Ricchi; Diego Cerrai
• Keywords: Flash flood; Quantitative precipitation forecast; Weather radar; Nowcasting

During the night between 9 and 10 September 2017, multiple flash floods associated to a heavy-precipitation event affected town of Livorno, located in Tuscany, Italy. Accumulated precipitation exceeding 200 mm two hours, with return period higher than years, caused all largest streams Livorno municipality flood several areas town. We used limited-area Weather Research Forecasting (WRF) model, convection-permitting setup, reconstruct extreme leading floods. evaluated possible forecasting improvements emerging from assimilation local ground stations X- S-band radar data into WRF, using configuration operational at meteorological center Tuscany region (LaMMA) time event. Simulations were verified against weather station observations, through an innovative method aimed disentangling positioning intensity errors forecasts. By providing more accurate descriptions low-level flow better assessment atmospheric water vapour, results demonstrate that assimilating improved quantitative