Publication Date:
2019-07-16
Description:
Information on soil surface state is valuable for many
applications such as climate studies and monitoring of permafrost
regions. C-band scatterometer data indicate good potential to
deliver information on surface freeze/thaw. Variation in state or
amount of water contained in the soil causes significant alteration
of dielectric properties of the soil which is markedly observ-
able in scatterometer backscattered signal. A threshold-analysis
method is developed to derive a set of parameters to be used
in evaluating the normalized backscatter measurements through
decision trees and anomaly detection modules for determination of
freeze/thaw conditions. The model parameters are extracted from
two years (2007 132008) backscatter data from ASCAT scatterome-
ter onboard Metop satellite collocated with ECMWF ReAnalysis
(ERA-Interim) soil temperature. Backscatter measurements are
flagged as indicator of frozen/unfrozen surface, and snowmelt or
existing water on the surface. The output product, so-called sur-
face state flag (SSF), compares well with two modeled soil temper-
ature data sets as well as the air temperature measurements from
synoptic meteorological stations across the northern hemisphere.
The SSF time series are also validated with soil temperature
data available at three in situ observation sites in Siberian region
showing the overall accuracy of about 80% to 90%.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
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isiRev
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