Enhanced Solar Radiation Forecasts with 15-Minute Intervals
Enhanced Solar Radiation Forecasts with 15-Minute Intervals
Cloud Detection Using Visible Light Satellite Observations
The German Weather Service, Deutscher Wetterdienst (DWD), has recently announced a significant enhancement to their weather forecasting models. This improvement involves the integration of satellite observations from the visible light spectrum into their data assimilation process, leading to a notable improvement in cloud and solar radiation predictions.
As part of this upgrade, the Open-Meteo DWD Forecast API now incorporates 15-minute weather forecasts from DWD, with a specific emphasis on providing accurate solar radiation forecasts.
The upgraded solar radiation forecast has the potential to be highly beneficial for individuals who own photovoltaic installations and want to predict their energy production levels.
15-Minutely Weather Forecast
DWD's ICON model provides 15-minute data for a select few weather variables in Central Europe, including direct and diffuse solar radiation, precipitation, snow, freezing height, and snowfall height.
The availability of 15-minute data is particularly significant for solar radiation forecasting, as this variable can change rapidly with cloud cover. The enhanced frequency of data can lead to more accurate solar radiation predictions, thereby improving the overall forecast quality.
The DWD ICON-D2 model covers a broad geographical region, encompassing Central Europe, including Germany, Denmark, Netherlands, Belgium, Switzerland, Czechia, Austria, as well as parts of neighbouring countries. The image below show the coverage of ICON-D2
The chart below illustrates the solar radiation forecast specifically for overcast days. Prior to the utilization of 15-minute data, this level of detail was unattainable with hourly data.
The 15-minutely forecast is now available in the Open-Meteo DWD API. As the availability of 15-Minutely data is limited to Central Europe and the DWD ICON model, this data is not yet available through the regular weather API.
Improved Solar Radiation Forecast
The latest upgrade to ICON, which occurred on March 15th, involves the integration of visible light spectrum data obtained from satellite observations into the DWD's assimilation process for weather models. Notably, DWD is the first national weather service to utilize visible light in this way.
Previously, only other parts of the light spectrum such as infrared radiation were used to estimate clouds and surface temperature. One advantage of the visible light spectrum is that it is also emitted during nighttime.
However, visible light can only be observed during daylight hours, and distinguishing between clouds, snow, and mineral dust or estimating the height and extent of clouds can be challenging. Despite this, research by Leonhard Scheck et al. and the Hans-Ertel Centre Munich has paved the way for the use of this data in weather models.
The introduction of the new satellite data assimilation not only enhances solar radiation forecasts, but also improves the overall forecast quality, since all weather variables in numerical weather models are physically interconnected. The verification results from DWD provide clear evidence of this improvement.
The DWD ICON weather models are included in the Open-Meteo weather API and are utilized by numerous weather websites. The DWD has earned a reputation for providing highly accurate weather forecasts, and they make all of their data available as open-data.
The upgrade to the DWD ICON model was formally announced via the DWD newsletter.