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| Titel |
Comparison of a coupled snow thermodynamic and radiative transfer model with in situ active microwave signatures of snow-covered smooth first-year sea ice |
| VerfasserIn |
M. C. Fuller, T. Geldsetzer, J. Yackel, J. P. S. Gill |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 6 ; Nr. 9, no. 6 (2015-11-18), S.2149-2161 |
| Datensatznummer |
250116872
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| Publikation (Nr.) |
 copernicus.org/tc-9-2149-2015.pdf |
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| Zusammenfassung |
| Within the context of developing data inversion and assimilation techniques
for C-band backscatter over sea ice, snow physical models may be used to
drive backscatter models for comparison and optimization with satellite
observations. Such modeling has the potential to enhance understanding of snow
on sea-ice properties required for unambiguous interpretation of active
microwave imagery. An end-to-end modeling suite is introduced, incorporating
regional reanalysis data (NARR), a snow model (SNTHERM89.rev4), and a
multilayer snow and ice active microwave backscatter model (MSIB). This
modeling suite is assessed against measured snow on sea-ice geophysical
properties and against measured active microwave backscatter. NARR data were
input to the SNTHERM snow thermodynamic model in order to drive the
MSIB
model for comparison to detailed geophysical measurements and surface-based
observations of C-band backscatter of snow on first-year sea ice. The NARR
variables were correlated to available in situ measurements with the
exception of long-wave incoming radiation and relative humidity, which
impacted SNTHERM simulations of snow temperature. SNTHERM snow grain size
and density were comparable to observations. The first assessment of the
forward assimilation technique developed in this work required the
application of in situ salinity profiles to one SNTHERM snow profile, which
resulted in simulated backscatter close to that driven by in situ snow
properties. In other test cases, the simulated backscatter remained 4–6 dB
below observed for higher incidence angles and when compared to an
average simulated backscatter of in situ end-member snow covers. Development
of C-band inversion and assimilation schemes employing SNTHERM89.rev4 should
consider sensitivity of the model to bias in incoming long-wave radiation,
the effects of brine, and the inability of SNTHERM89.Rev4 to simulate water
accumulation and refreezing at the bottom and mid-layers of the snowpack.
These impact thermodynamic response, brine wicking and volume processes,
snow dielectrics, and thus microwave backscatter from snow on first-year
sea ice. |
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