FMI ARK SAT QA Portal

FMI ARK SAT QA Portal

Satellite derived products vs in-situ snow depth data

In this comparison, FSC values from satellite products are compared with SD values from in-situ measurements, which are available through FMI open data.

After collecting all data pairs, binary snow cover information (snow covered or snow free) is determined by using FSC and SD thresholds. These thresholds can be changed from the "Comparison options" menu. Invalid values (nan, cloud, dark etc.) are discarded. 'N days' in maps corresponds to the number of days which has valid data for each location.

Accuracy Maps show accuracy values calculated using data pairs for each location in contingency tables. Accuracy from 0% to 100% is colored from red to green. False Alarm Rate Maps show false alarm rate values calculated using data pairs for each location in contingency tables. False alarm rates from 0% to 100% is colored green to red. If FAR cannot be calculated, the data location is shown in white color.

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 options

Satellite product:
Satellite prod. threshold (%):
Insitu data threshold (cm):
Start date:
End date:
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