Harmonization of multi-mission high resolution time series: application to BELAIR.

Introduction

The BELHARMONY project responds to the need of the Belgian and international EO community to have improved consistency in time series generated on the basis of a constellation of medium to high resolution satellite sensors.

There is a clear tendency in the use of higher spatial resolution satellite sensor both for land  and water applications. Due to the low revisit time of these sensors and the frequent cloud coverage, many applications require data from different missions to be combined  in order to have more frequent observations. This joint use of data from different sensors raise some clear concerns about data consistency.

Objectives

The overall objective of the BELHARMONY project is to assess and improve the consistency of multi-sensor high resolution time series generated on the basis of the following sensors:  Deimos-1, Sentinel-2, Landsat-8  and PROBA-V.

Approach

The approach will consist of 1) the assessment and correction of radiometric biases at the TOA level through the application of a set of independent vicarious calibration methods and considering low, medium and high scene brightness values, 2) the derivation of spectral response adjustment factors to compensate for difference in the relative spectral response curves 3) the use of a common processing chain for the processing of the Level1 data up to Level2 reflectance and L3 higher level products.

To evaluate the impact of the various harmonisation measures on the multi-sensor L2 and L3 time series, BELHARMONY will make use of the extensive set of EO data and in-situ reference data which have been systematically collected over the BELAIR urban, agricultural and coastal waters sites. The BELAIR initiative, which has started in 2013, aims to develop Belgian test sites, for which targeted EO data and other measurement results are collected, on behalf of the Belgian and international research communities, and which may be used as calibration and validation sites for new EO missions, data and products.

PROBA-V image from the RadCalNet  Railroad Valley Playa (USA) site
PROBA-V image from the RadCalNet Railroad Valley Playa (USA) site

Duration

The Belhormony project started on the 1st  December 2017 and will have a duraction of 30 months.

Acknowledgement

BELHARMONY is funded by BELSPO in the frame of the StereoIII programme (Contract SR/00/356)