Sensitivity analysis of the WRF model: Assessment of performance in high resolution simulations in complex terrain in the Canary Islands
Introduction
Extreme weather events have negative impacts on transportations and communications, consequently resulting in catastrophic effects on distinct aspects of people's lives and economy. Despite the apparent climatic mildness, the frequency and intensity of the severe weather events have serious consequences on the Canary Islands (Dorta, 2007). To understand this impact, statistics show that severe weather events caused 74 fatalities between 1995 and Eiserloh, 2014 (Suárez-Molina et al., 2018). According to the CCS (“Consorcio de Compensación de Seguros”, a public organization funded by the Ministry of Economy, Industry and Competitiveness of the Spanish Government), between 1996 and 2018, floods and windstorms in the Canary Islands produced more than 211 million Euros in losses (Suárez-Molina et al., 2020).
The accuracy of Numerical Weather Prediction (NWP) models in complex terrain is lower than over flat and homogeneous terrain. This discrepancy is attributed to the fact that boundary-layer processes in complex terrain are not well represented by NWP models. Previous studies have evaluated the performance of different planetary boundary layer (PBL) parameterization schemes in locations known for complex atmospheric situations (Pérez et al., 2006; Bossioli et al., 2009). Microphysics schemes in numerical models play a key role in simulating the formation of cloud droplets, precipitation, and land surface temperature. It also takes into account the interactions and energy fluxes between the atmosphere and the surface, which is considered a key parameter in many hydrological, meteorological and environmental studies (Anderson et al., 2011).
In recent years, the use of the Weather Research and Forecasting (WRF) model in operational mode has increased. For instance, since 2017, the National Centers for Environmental Prediction (NCEP) use in operational mode the Hurricane Weather Research and Forecast (HWRF) system (Biswas et al., 2018). In addition, the WRF model has been used by other authors in operational mode with different purposes (Hsiao et al., 2012; Hamill, 2014; Sahoo et al., 2019). The WRF model is also being used in γSREPS, an Ensemble Prediction System developed by AEMET, the Spanish Meteorological Agency (Callado et al., 2019).
Although other studies have used WRF in the Canary Islands for particular phenomena (Marrero et al., 2008; Jorba et al., 2015; Quitián-Hernández et al., 2018), a comprehensive sensitivity analysis has not been carried out before. Such study is essential to determine the most convenient model setup for this geographical domain (Borge et al., 2008). In addition, it should be taken into consideration that the operational forecast of convective episodes is more problematic in subtropical regions such as the Canary Islands (Žagar et al., 2005).
The purpose of this work is to evaluate the quality of WRF forecasts in the Canary Islands. The fields analyzed–air temperature at 2 m (T2m), maximum 1-h wind gust at 10 m and 3-h rainfall accumulation–are of vital importance for issuing meteorological warnings (METEOALERTA, 2018). The period analyzed (15 days in February 2018) includes various weather patterns; therefore, the sensitivity analysis will evaluate the model performance under different atmospheric conditions.
This paper is structured as follows: Section 2 describes the study area, the configuration of the WRF experiments and the observational dataset used to evaluate the model performance. Section 3 presents the results of the performance evaluation. Finally, Section 4 summarizes the paper conclusions.
Section snippets
Study area and dataset
This research is focused on the Canary Islands (Fig. 1). This archipelago is in front of the west coast of North Africa in the subtropical zone (27°37′–29°25′N and 18°10′–13°20′W). The archipelago is formed by seven islands of volcanic origin that present a complex orography. The highest point is Mount Teide (3718 m) on Tenerife (TF). With Tenerife being by far the highest island, La Palma (LA), Gran Canaria (GC), La Gomera (GO) and El Hierro (HI) constitute a medium cluster with highest
Results and discussion
The results section is structured as follows; in Section 3.1 we will present the results of the sensitivity analysis where we discuss the different scores for the six configurations; then, we will study the dependency to the lead time (Section 3.2), to the location (Section 3.3), and altitude (Section 3.4).
Conclusions
Sensitivity analysis can be used to determine optimum WRF model configurations. However, the best configuration depends on location and meteorological conditions. In this research, a comprehensive sensitivity analysis has been carried out in the Canary Islands. Due to the impact on the socio-economic activities, the analysis has been focused on T2m, wind gust and 3-h rainfall accumulation. Subsequently, the most relevant conclusions are summarized:
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This research allowed discarding inappropriate
Author statement
The paper entitled “Sensitivity analysis of the WRF Model: Assessment of performance in high resolution simulations in complex terrain in the Canary Islands” was carried out by the authors David Suárez-Molina, Sergio Fernández-González, Gustavo Montero, Albert Oliver and Juan Carlos Suárez González. In the following lines, the contribution of each author will be detailed:
David Suárez-Molina: He is the main contributor to this paper, being the responsible of the conceptualization, design of the
Declaration of Competing Interest
The authors claim that there is no conflict of interest, nor any funding source that intercedes with the free publication of results obtained in this research.
Acknowledgements
Observational data are provided by the State Meteorological Agency of Spain (AEMET). The authors are grateful to the Weather Forecast Research Team for developing “Verif” software. Special thanks go to the SAFEFLIGHT (CGL2016-78702-C2-1-R and CGL2016-78702-C2-2-R) and UE ERA-NET Plus NEWA (PCIN2016-080) projects.
References (61)
- et al.
Sensitivity of boundary-layer variables to PBL schemes in the WRF model based on surface meteorological observations, lidar, and radiosondes during the HygrA-CD campaign
Atmos. Res.
(2016) - et al.
A comprehensive sensitivity analysis of the WRF model for air quality applications over the Iberian Peninsula
Atmos. Environ.
(2008) - et al.
Performance of multi-physics ensembles in convective precipitation events over northeastern Spain
Atmos. Res.
(2017) - et al.
Sensitivity of WRF model estimates to various PBL parameterizations in different climatic zones over India
Atmos. Res.
(2017) - et al.
Assessment of the WRF model in reproducing a flash-flood heavy rainfall event over Korea
Atmos. Res.
(2009) - et al.
Influence of the PBL scheme on high-resolution photochemical simulations in an urban coastal area over the Western Mediterranean
Atmos. Environ.
(2006) - et al.
Analysis of sensitivity to different parameterization schemes for a subtropical cyclone
Atmos. Res.
(2018) - et al.
Analysis of sounding derived parameters and application to severe weather events in the Canary Islands
Atmos. Res.
(2020) WRF-Model Data Assimilation Studies of Landfalling Atmospheric Rivers and Orographic Precipitation Over Northern California
(2014)- et al.
A two-source time integrated model for estimating surface fluxes using thermal infrared remote sensing
Remote Sens. Environ.
(2011)