Other instrument characterisation and product validation studies
Read other instrument characterisation and product validation studies for operational, future and multi-missions.
30 January 2023
04 March 2019
Precise geolocation of satellite imagery is fundamental for systematic climate observations. It allows multi-sensor composites and long-term time series of Essential Climate Variables (ECVs). The World Meteorological Organization (WMO) summarizes baseline requirements for satellite-based climate products in (GCOS 2006). It requires for moderate-resolution optical instruments a geolocation accuracy better than 1/3 of the instantaneous field of view (IFOV) in the terrestrial domain.
The tool supports Level-1 products from the current medium resolution (MROI) EUMETSAT sensors AVHRR/3, SLSTR and OLCI and is extendable to near-future sensors. For the shift estimation, an iterative area-based cross-correlation method was selected to match Landsat-8 NIR and TIR bands against MROI-DataWindows (MROI-DW). The Geolocation Assessment Tool has a modular design. It consists of a Core Module and a Reporting Module.
The main project objectives are
The Geolocation Assessment Tool has a modular design. It consists of a Core Module and a Reporting Module.
The core module performs the calculation of the geolocation shifts between MROI and high-resolution reference data using features which are clearly identifiable in MROI data sets (such as lakes, islands).
The reporting module takes care of visualisation (Figure1), evaluation and analyses of geolocation shifts and generation of reports.
Figure 2 shows the concept of the processing line. Input to the procedure are Level1B (swath geometry) or Level-2 (geocoded) MROI data from Metop AVHRR/3, and Sentinel-3A/B SLSTR and OLCI. The module design allows to add other and upcoming MROI sensors like MetImage.