FMI ARK SAT QA Portal |
FMI ARK SAT QA Portal |
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Satellite derived products vs Webcam derived dataIn those comparisons, FSC (SCE) values from satellite derived snow products are compared with FSC values derived from webcam images, which are available in the operational monitoring processing chains. Webcam derived data is fetched from the FMIPROT Download data API. "Snow cover fraction" parameter is calculated are included in the comparison. Temporal extent and the data producing algorithm can be selected using the dialog below.If the webcam derived data contains ROI Geolocation information, ROI is used for the selection of satellite product pixels. If ROI is not provided, camera location is used. For the "Point" type ROIs and camera locations, single pixel which corresponds to that point is used for each webcam derived data point. For the "Polygon" type ROIs, all the pixels whom their cell area intersects with the ROI are used, for each webcam derived data point. After collecting all data pairs, their median value for each day and camera location (all the points in ROI together) are calculated. Invalid values (nan, cloud, dark etc.) are discarded. "N points" in the plots corresponds to the number of data pairs for those each location for each day. "N days" in maps correspond to the number of days which has valid data for each location. RMSE Maps show RMSE values calculated from all the (daily median) data pairs for each location. RMSE from 0 to 100 is colored from green to red. Scatter Plots show daily value (median) pairs for each location. Different locations are colored differently. Maps and plots will only be visible if there is any valid data in comparison. For example, there may be no valid data in winter days due to the camera data corresponds to the low sun zenith angle (polar night) pixels. Comparison optionsLoading...
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