Abstract
Preprint of a paper that is submitted to the “Journal of Selected
Topics in Earth Observation and Remote sensing” with the following
abstract:
It is widely assumed that C-Band Synthetic Aperture Radar (SAR) signal
do not reach the forest floor in dense forests, and that hence C-Band
SAR cannot be used for sub-canopy flood mapping in tropical forests.
Indeed, flooded and non-flooded forests are not distinguishable in
single C-Band acquisitions. The question is whether long-term seasonal
dynamics in C- Band SAR time series data encode flooding dynamics under-
neath the canopy. In this paper we investigate the relationship of
Sentinel-1 backscatter with sub-canopy flooding in the Amazon rain
forest. We use the Empirical Mode Decomposition to extract annual modes
in the backscatter signal and use the correlation to the water level of
a nearby river to understand the dynamics of the Sentinel-1 signal.
Clusters of these correlations coincide well with known forest flooding
areas in the VH signal. The analysis shows that the Sentinel-1 C-Band
backscatter is influenced by floodings underneath the canopy in the
Amazon rain forest. The presented approach could allow to systematically
map flooded areas throughout tropical rain forests.