Improvements to atmosphere-land exchange analysis

Objectives

The objectives of IMPALA are the following ones:

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EVALUATION-CORRECTION of existing pre-processing techniques for the full range of Earth Observation Satellites, with a view to expand and update ITC's capacity to integrate new satellite technology into the existing framework. Pre-processing includes geometric, radiometric and atmospheric correction techniques.

-	THEORY/MODELLING of Land-Surface interactions will be analyzed in co-operation with the ongoing research projects (Projects 1 and 2, SRON ECORTM, EAGLE). Modelling by means of the current principal techniques, SEBS, TSEB and SEBAL will yield valuable conceptual and algorithmic improvements.

-	FIELD VALIDATION/DEMONSTRATION will provide an opportunity to test potential improvements in algorithms and physical parameters obtained with the improved conceptual analysis.

-	RECOMMENDATIONS to indicate the new algorithms and sensor configurations that should be considered in the near future for improved parameter estimation in GMES products.

Maim activities

The three main project-related activities are:

-	Satellite platforms and image pre-processing

-	Theory of atmospheric turbulent transport and flux algorithms for remote sensing

-	Field calibration and validation

An essential condition for this research is that low-cost, high performance pre-processing methods are developed for the full range of satellites with thermal bands: NOAA, LANDSAT, MODIS, ASTER, GOES AND METEOSAT. Pre-processing includes geometric and radiative transfer corrections. Atmospheric correction should be introduced at operational level.

The theory of turbulent transport needs to be developed further to reliably accommodate satellite derived multi-angle, multi-spectral and hyperspectral information. Robust algorithms need to be designed to allow high-performance processing of image time series. The models currently used in ITC, need improvement and increased versatility for enhanced performance required by the strongly increasing volume of Earth Observation data.

The results of (B) need to be calibrated and validated against a number of ground control stations, before application to assess the water balances of diverse terrain and vegetation. The type of ground control (flux towers with footprints in representative cover types and moisture; scintillometers measuring fluxes over a few km, upscaled sapflow, catchment water balances) will allow testing the algorithms for spatial application and development of inverse solutions for aerodynamic and interfacial layer parameters.

The effect various cover types on the components of the Water Cycle will be analyzed by improved algorithms (A and B) and by field data (C) in three areas:

Barrax (Spain): Regular fieldwork has been carried out by partners in the European network for many years and a huge database of ground data is now available. This allows cross-calibration of the currently proposed Land-Atmosphere Interaction mechanisms.

Waterschap Regge and Dinkel (Netherlands): The flux determination pertains to sparser trees and grass cover in humid environment. The analysis is expected to yield important results with regard to quantification of water cycle components in mixed tree/grass and wetland environments.

Okavango (Maun, Botswana): In the environment of the large inland delta, a nature reserve of world fame, wet areas and forests are found next to drier terrain with associated vegetation. No good water balance exists to determine a sound water balance in this difficult terrain, the ETa losses must be studied. The problem in the dry areas is to assess the Eta flux from varied semi-arid vegetation types, ranging from fairly dense forest savanna, with deep rooted species to poor grass covers. The wet areas can be used for method calibration