Comparison of radiation parametrizations within the HARMONIE–AROME NWP model

Laura Rontu,Anders V Lindfors

doi:10.5194/asr-15-81-2018

Laura Rontu, Anders V Lindfors

Open Access

https://doi.org/10.5194/asr-15-81-2018

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Abstract

Abstract. Downwelling shortwave radiation at the surface (SWDS, global solar radiation flux), given by three different parametrization schemes, was compared to observations in the HARMONIE–AROME numerical weather prediction (NWP) model experiments over Finland in spring 2017. Simulated fluxes agreed well with each other and with the observations in the clear-sky cases. In the cloudy-sky conditions, all schemes tended to underestimate SWDS at the daily level, as compared to the measurements. Large local and temporal differences between the model results and observations were seen, related to the variations and uncertainty of the predicted cloud properties. The results suggest a possibility to benefit from the use of different radiative transfer parametrizations in a NWP model to obtain perturbations for the fine-resolution ensemble prediction systems. In addition, we recommend usage of the global radiation observations for the standard validation of the NWP models.

Highlights

Future numerical weather prediction (NWP) models will increasingly be devoted to very high-resolution and rapid updates due to the needs of forecasting details in short timescales
The results suggest a possibility to benefit from the use of different radiative transfer parametrizations in a NWP model to obtain perturbations for the fine-resolution ensemble prediction systems
In response to the ongoing rapid development of the solar energy sector, the capability of NWP models to predict observed solar shortwave (SW) radiation conditions at the surface has been put under scrutiny in recent studies (LaraFanego et al, 2012; Kosmopoulos et al, 2015; Federico et al, 2017)

Summary

Introduction

Future numerical weather prediction (NWP) models will increasingly be devoted to very high-resolution and rapid updates due to the needs of forecasting details in short timescales. In view of predictability challenges at high resolution it is desirable to apply probabilistic methods even at the short forecast ranges. In response to the ongoing rapid development of the solar energy sector, the capability of NWP models to predict observed solar shortwave (SW) radiation conditions at the surface has been put under scrutiny in recent studies (LaraFanego et al, 2012; Kosmopoulos et al, 2015; Federico et al, 2017). For the development of the solar energetics, observational data of downwelling shortwave radiation at the surface (SWDS) distribution are increasingly needed and measurement stations are being set up globally

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