Study of NWP parameterizations on extreme precipitation events over Basque Country

Iván R Gelpi,Joseba Egaña,Roberto Hernández,Sheila Carreño,Santiago Gaztelumendi

doi:10.5194/asr-13-137-2016

Iván R Gelpi, Joseba Egaña + Show 3 more

Open Access

https://doi.org/10.5194/asr-13-137-2016

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Abstract

Abstract. The Weather Research and Forecasting model (WRF), like other numerical models, can make use of several parameterization schemes. The purpose of this study is to determine how available cumulus parameterization (CP) and microphysics (MP) schemes in the WRF model simulate extreme precipitation events in the Basque Country. Possible combinations among two CP schemes (Kain–Fritsch and Betts–Miller–Janjic) and five MP (WSM3, Lin, WSM6, new Thompson and WDM6) schemes were tested. A set of simulations, corresponding to 21st century extreme precipitation events that have caused significant flood episodes have been compared with point observational data coming from the Basque Country Automatic Weather Station Mesonetwork. Configurations with Kain–Fritsch CP scheme produce better quantity of precipitation forecast (QPF) than BMJ scheme configurations. Depending on the severity level and the river basin analysed different MP schemes show the best behaviours, demonstrating that there is not a unique configuration that solve exactly all the studied events.

Highlights

In the last years, several events of heavy precipitation over the Basque Country have caused different flood episodes
We present a preliminary comparison of different microphysics and cumulus parameterization schemes in the Weather Research and Forecasting model (WRF) quantity precipitation forecast (QPF) for 21st century extreme precipitation events in the Basque Country
The analysis of the results show that the 9 km resolution domain, for most of the events and experiments, works better for QPF (Quantitative Precipitation Forecast) than other domains, including 3 km resolution

Summary

Introduction

Several events of heavy precipitation over the Basque Country have caused different flood episodes. In order to understand the occurrence and dangerousness of these flood episodes, a full study was made including synoptic, mesoscale information and local meteorological characteristics. In the Basque Country Agency (Euskalmet), different Numerical Weather Prediction (NWP) models run operationally (Egaña et al, 2008; Gaztelumendi et al, 2007, 2009; Gelpi et al, 2007, 2013). We present a preliminary comparison of different microphysics and cumulus parameterization schemes in the WRF quantity precipitation forecast (QPF) for 21st century extreme precipitation events in the Basque Country. We focus on particular river basins in the Basque Country for a selection of severe episodes. Analysis and validation are based mainly on rain data from the Basque Country Automatic Weather Station (AWS) Mesonetwork (Gaztelumendi et al, 2003)

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