On Solar Radiation Prediction for the East–Central European Region

Abstract

The aim of this paper is to present the results of the Weather Research and Forecasting (WRF) model of solar radiation for moderate climatic zones. This analysis covered the area of northeastern Germany. Due to very unfavorable solar energy conditions in this region for at least 1/3 of the year, we decided to select the dates with the most representative conditions: passing warm fronts, cold fronts, and occluded fronts (two cases each). As the reference, two cloudless conditions during high-pressure situations were chosen. Two different shortwave radiation schemes—Rapid Radiative Transfer Model for general circulation model (RRTMG) and Dudhia—were tested. The obtained results were compared with in situ data measured at Deutscher Wetterdienst (DWD) stations and then with European Medium-Range Weather Forecast reanalysis (ERA5) data. The results showed that for high-pressure situations, the mean correlations with measured data were above 90%. The Dudhia scheme, in addition to the expected good results for the high-pressure situation, showed better results than RRTMG for the warm and cold fronts as well. The forecast using the RRTMG scheme gave the best results for the occluded front, which were also better than those of the ERA5 model.

WRF Parameterizations of Short-Term Solar Radiation Forecasts for Cold Fronts in Central and Eastern Europe

“…For the selected 18 synoptic situations, the Pearson's correlation coefficients ranged from 0.49 to 0.92, depending on the WRF model configuration. These values are slightly higher than those obtained in earlier studies [17]. The dates from the autumn-winter period are characterized by lower values of the indicators RMSE, MAE and MBE.…”

“…These mainly come from the western sector, bringing a change in atmospheric conditions, most often transporting polar-maritime air masses that are rich in moisture, which bring cooling and precipitation in summer, while in autumn and winter they are associated with warming and precipitation. The forecasting effectiveness for synoptic situations associated with moving atmospheric fronts, especially cold fronts, is much worse than for high pressure situations, as previous analyses have shown [17].…”

“…Numerical Weather Prediction (NWP) models used for the prediction of atmospheric conditions perform admirably in high pressure situations (for forecasts of solar conditions-global horizontal irradiance-Pearson's correlation against data obtained from in situ measurements is characterized by values well above 0.9) [17,18]. One of these models, the Weather Research and Forecasting model (WRF), is used to forecast many meteorological elements at different spatial scales for predictions of different lengths [19,20].…”

“…The results showed that the WRF performed best compared to the other mesoscale models; however, the simulations covered 7 days, but did not specify the synoptic conditions for which the predictions were made. Another study [17] analyzed forecasts of solar conditions for north-eastern Germany for the most unfavorable synoptic situations (days with moving atmospheric fronts), which represent a significant proportion of the annual weather conditions. The study showed that the WRF model used had good results for days with warm fronts or occluded fronts.…”

Impact of Domain Nesting on High-Resolution Forecasts of Solar Conditions in Central and Eastern Europe

“…The above solutions have a particularly important impact on the prediction of meteorological elements or phenomena directly or indirectly related to cloud cover (cloud cover, rainfall, snowfall, solar radiation, etc.) [40][41][42]64,66,67]. Designing the optimal domain and selecting the appropriate model parameterization and forecast duration allowed us to obtain the desired forecast quality of a specific element or group of meteorological elements [23,66,68].…”