The Tarkka-service includes satellite observations as well as supplementary datasets, such as GIS-datasets, basemaps, and validation abd modelled datasets from in-situ station measurements.

Satellite instruments utilized by Tarkka

The high-resolution (10 m – 60 m) satellite observations presented in Tarkka currently consist of data from two satellite instruments. The service leverages two Sentinel-2 series satellites (S2A and S2B) and their Multispectral Imager (MSI) instruments, as well as two Landsat series satellites (LC8 and LC9) and their Operative Land Imager (OLI) instruments. The orbits of these satellites cover the Finnish territory several times a week, capturing imagery of specific sections of the Earth’s surface during a single day. Consequently, the high-resolution true-color images and interpretations available in the Tarkka service are “sliced,” and daily interpretations do not always cover the entire extent of Finland.

In addition to high-resolution datasets, Tarkka also includes mid-resolution (300 m – 1 km) satellite observations. The most up-to-date observations are produced by the Sentinel-3 satellite’s OLCI and SLSTR instruments. Historical data from previous years are based on observations from the NOAA AVHRR, Envisat MERIS, and MODIS instruments

The default view of the Tarkka

In the default view of Tarkka, a combination of the latest true-color images from all available satellite instruments is displayed for the given day. The coarsest resolution observation (300 m, Sentinel-3 OLCI) is shown at the bottom, and the higher resolution observations are layered on top for areas where such data is available. The highest resolution observations are produced by the Sentinel-2 MSI and Landsat-8/-9 OLI instruments. By default, the most detailed Sentinel-2 images with 10 meter spatial resolution are displayed on top if they are available.

The dataset theme can be changed from the drop-down menu on the left, and individual datasets can be toggled on and off using the accordion menu. You can also adjust the view settings and visibility of datasets from the accordion menu.

The Tarkka datasets

Satellite observations

Daily interpretation datasets (each described in more detail on their own subpage). Activate from the accordion menu. Data is available for days when interpretation was possible (observations exist for the target area, and the day was sufficiently cloudless).