Dynamic mosaic of Sentinel-2 data NW

The dynamic mosaic consists of current cloud-free images of Sentinel-2 orthoimages. The two identical Sentinel-2 satellites of the European Earth observation programme Copernicus have been continuously providing images of the Earth’s surface since 2015 and 2017. The multispectral optical sensor has 13 spectral channels in the visible and infrared range. The spatial resolution varies from 10 m (channels B02, B03, B04, B08) over 20 m (channels B05, B06, B07, B08A, B11, B12) up to 60 m (channels B01, B09, B10). The Sentinel-2 data is originally offered in the processing levels Level 1C (Top-Of-Atmosphere) and Level-2A (Bottom-Of-Atmosphere) and is provided in tile sizes of 100 x 100 km² in UTM/WGS84 projection. For NRW, the high recurrence rate of the satellites provides up-to-date images every 2-3 days. However, since the multispectral instrument is a passive system, the usability of the recordings is weather dependent. The available ortho-images have different degrees of cloud coverage. To derive the dynamic mosaic, the current Sentinel-2 images are checked for cloud cover so that the cloud-free areas can be selected. Areas of older images are continuously replaced with current cloud-free images. The 4 spectral bands with a spatial resolution of 10 m (red, green, blue, near infrared) of the level 2A data are taken into account. If a cloud-free range exists, the data set is updated from a size of 100 consecutive 10 m x 10 m pixels, so that the current cloud-free images are always included in the mosaic. The Dynamic Mosaic is provided as a representation service in RGB (composite of the spectral bands B04-B03-B02) and CIR (composite of the spectral bands B08-B04-B03). In addition, the recording date of the respective Sentinel-2 scene is provided for each cloud-free area. The recording date is displayed via the material data query of the metadata layer.