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| Titel |
Evaluation of a 1-D snowpack model SMAP applied in the Greenland ice sheet |
| VerfasserIn |
Masashi Niwano, Teruo Aoki, Sumito Matoba, Satoru Yamaguchi, Tomonori Tanikawa, Hideaki Motoyama, Katsuyuki Kuchiki |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077860
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| Zusammenfassung |
| Snow and ice on the Greenland ice sheet (GrIS) are melting rapidly in recent years. In order
to understand the mechanism and to perform reliable future projection on the mass balance of
GrIS, we employ the 1-D physical snowpack model named Snow Metamorphism and Albedo
Process (SMAP), which was originally developed and validated against seasonal snowpack,
and adapt it for the simulation of polar snowpack. In the present study we tested SMAP using
the data obtained during the 2012 intensive field observations (30 June to 13 July,
2012) conducted in the site SIGMA-A, which locates on northwest part of GrIS (78Ë
03’N, 67Ë 38’W, 1,490 m a.s.l.). During the latter half of the expedition period we
encountered the record melt event where surface snow and ice over 97% of GrIS
melted abruptly. In the model test the initial physical states of snowpack were given
from those obtained by snow-pit observations carried out on 30 June. From the
initial state we calculated temporal evolution of physical parameters of snowpack by
forcing measured meteorological data, mass concentrations of snow impurities,
and snow temperature at the depth of bottom ice formation in the latest annual
layer (initial depth was 88 cm). The model performance was evaluated in terms
of snow surface temperature, shortwave albedo, relative snow depth (to the ice
formation in the latest annual layer), profiles of snow temperature, and snow density.
Regarding snow surface temperature and shortwave albedo SMAP overestimated both,
nevertheless biases were small (+0.143 Ë C and +0.014, respectively), suggesting that the
snow-atmosphere energy exchange (snow surface energy balance) is modeled adequately.
To calculate accurate relative snow depth it is necessary to simulate mass balance
precisely. The acquired small bias (-0.026 m) shows that SMAP estimates mass balance
successfully. Finally, as for profiles of snow temperature and snow density we found that
SMAP tended to underestimate the former, while overestimate the latter. However,
obtained small biases (less than 1 Ë C and ranged between 30 and 90 kg m-3,
respectively) indicate that SMAP calculates internal physical properties of snowpack in an
appropriate manner if relevant upper and lower boundary conditions are imposed. |
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