Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11028667 | International Journal of Applied Earth Observation and Geoinformation | 2019 | 9 Pages |
Abstract
The Above-Ground Biomass (AGB) is a key parameter used for the modeling of the carbon cycle. The aim of this study is to make an experimental assessment of the sensitivity of Global Navigation Satellite System (GNSS) reflected signals to forest AGB. This is based on the analysis of the data recorded during several GLORI airborne campaigns in June and July 2015, over the Landes Forest (France). Ground truth measurements of tree height, density and diameter at breast height (DBH), as well as AGB, were carried out for 100âmaritime pine forest plots of various ages. The GNSS-R data were used to obtain the right-left (ÎRL) and right-right (ÎRR) reflectivity observables, which are geo-referenced in accordance with the known positions of relevant GPS satellites and the airborne receiver. The correlations between forest AGB and the GNSS-R observables yield the highest sensitivity at high elevation angles (70°-90°). In this case, for (ÎRL) and the reflectivity polarization ratio (PRâ=âÎRL/ÎRR) estimated with a coherent integration time Tcâ=â20âms, the coefficients of determination R2 are equal to 0.67 and 0.51, with a sensitivity of â0.051âdB/[106g (Mg)âhaâ1], and â0.053âdB/[Mgâhaâ1], respectively. The relationships between AGB and the observables are confirmed through the use of a 5-fold cross validation approach, with several different coherent integration times.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Computers in Earth Sciences
Authors
Mehrez Zribi, Dominique Guyon, Erwan Motte, Sylvia Dayau, Jean Pierre Wigneron, Nicolas Baghdadi, Nazzareno Pierdicca,