Sunshine analysis

### Description The “sun” layers represent simulations of theoretical sunshine based on the numerical model of the surface. These simulations take into account topographical situations (arounds, slopes, exposures) and temporary variation during the year of theoretical sunshine for a specific geographical position. This analysis creates two types of results in the form of a grid with a resolution of 1 m: — A visualisation of the duration of sunshine in hours per day — An accumulation of potential solar energy in Watt/m² per day Currently, this analysis has been calculated for three days, including 15/02 (winter), 15/05 (spring) and 15/08 (summer) on the 2017 digital surface model made available by the National Air Administration (ANA). ([Link to MNS dataset](https://data.public.lu/fr/datasets/digital-surface-model-high-dem-resolution/)) The sunshine analysis was carried out with the “Zonal Solar Radiation” tool of the ESRI ArcMap software. Detailed documentation is available [here](http://desktop.arcgis.com/fr/arcmap/latest/tools/spatial-analyst-toolbox/area-solar-radiation.htm). Detailed documentation of the insolation calculation used is available [here](http://desktop.arcgis.com/fr/arcmap/10.3/tools/spatial-analyst-toolbox/how-solar-radiation-is-calculated.htm). ### The parameters used for analysis **Raster at the entrance**: Digital surface model made available by the Aviation navigantion Administration (ANA) based on 2017 LiDAR data. **Latitude**: 49.46 ° **Configuration of time**: Time Within a day (for 3 dates: 15/02 winter, 15/05 spring and 15/08 summer) **Time interval**: 0.5 30 minute intervals are used and data is accumulated per day. **Slope and exhibition**: Slope and exposure rasters are calculated from the input surface numerical model. **Number of azimutal directions**: 32 directions. This number is suitable for complex topography. **Proportion of global normal radiation flux**: The value used is 0.3 for clear sky conditions. **Fraction of radiation passing through the atmosphere**: 0.5 for clear sky conditions. **Grid of the duration of direct sunshine**: Output raster corresponding to the duration of direct solar radiation in hours per day. ## Data structure and format The data are available in the geotif format with 1 m resolution (LUREF coordinate system — EPSG: 2169). For each date, there is a duration file with the duration of sunshine in hours per day and a radiation file with potential solar energy in Watt/m² per day.