Operational LST algorithms

As already mentioned there are many different methods to retrieve LST by satellite and the choice of algorithm depends on several factors such as the available input data and purpose. For instance, an operational algorithm cannot be computationally heavy. Moreover, an operational LST product is required to meet a predefined target accuracy and has to prove it is stable (does not depart from target accuracy over time).

Validation activities are critical to prove the target accuracy of a given product is achieved. This is usually done by comparison against parameters retrieved from sensors onboard other platforms and in situ measurements. However, surface stations where radiometric measurements can be made are few and far between, except during special field campaigns.

Fig. 30: KIT- validation station, Gobabeb, Namibia. Source: 6th LSA SAF Workshop. Radiometric in situ measurements over European & African sites for validating LSA SAF's land surface temperature product. Frank Göttsche.

The Karlsruhe Institute of Technology, a participant in the LSA SAF, runs the only four currently permanent LST validation stations worldwide. Their locations were planned to cover all relevant climate zones (except inner tropics) in Meteosat's field of view. They are in Evora, Portugal (moderate climate with four seasons); Dahra, Senegal (dry and rainy seasons); Gobabeb, Namibia (desert climate); and RMZ farm in Kalahari, Namibia (semi-desert at 1600 m asl). For more information see Frank Göttsche's report from the 6th LSA SAF Workshop: 'Radiometric in-situ measurements over European & African sites for validating LSA SAF's land surface temperature product'.