Impact of initial conditions on modelling extreme precipitation: case of November 29–30, 2010 floods over Morocco

Autor: Sahlaoui, Zahra, Hdidou, Fatima Zahra, Rhaz, Khalid El, Mordane, Soumia
Zdroj: Modeling Earth Systems and Environment; November 2022, Vol. 8 Issue: 4 p5683-5693, 11p
Abstrakt: Extreme Precipitation is a weather hazard that affects the society directly and harmfully. Because of the process involved in the formation of precipitation at several spatial and temporal scales, the forecast of precipitation is still challenging the weather models. The aim of this work is to evaluate the impact of initial condition on the modelling of extreme precipitation by the Numerical Weather Prediction (NWP) limited area model ALADIN (Aire Limitée Adaptation dynamique Developpement INternational) at 10 km horizontal resolution. The case study corresponds to the extreme flooding event of November 29–30, 2010 across Morocco with daily precipitation reaching 178 mm over Casablanca city. A detailed description of the atmosphere dynamic during this event is given to help the understanding of the precipitation generation. Several experiments were performed to assess the impact of conventional and satellite data. Furthermore, sensitivity studies were carried out for the surface initialisation and the start mode. The assimilation experiment with an optimal setting had produced dynamical fields that were more favourable for the heavy precipitation occurrence. The evaluation of precipitation forecast has been performed by comparison to the surface precipitation observations. The results showed that the combined surface/upper-air assimilation of both conventional and satellite observations produced a clear improvement in term of precipitation location and intensity forecast.
Databáze: Supplemental Index