 |
| Titel |
Vital role of daily temperature variability in surface mass balance parameterizations of the Greenland Ice Sheet |
| VerfasserIn |
I. Rogozhina, D. Rau |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1994-0416
|
| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 2 ; Nr. 8, no. 2 (2014-04-07), S.575-585 |
| Datensatznummer |
250116087
|
| Publikation (Nr.) |
 copernicus.org/tc-8-575-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| This study aims to demonstrate that the spatial and seasonal effects of
daily temperature variability in positive degree-day (PDD) models play a
decisive role in shaping the modeled surface mass balance (SMB) of
continental-scale ice masses. Here we derive monthly fields of daily
temperature standard deviation (SD) across Greenland from the ERA-40 (European Centre for Medium-Range Weather Forecasts
40 yr Reanalysis) reanalysis spanning from 1958 to 2001 and apply these fields to model recent
surface responses of the Greenland Ice Sheet (GIS). Neither the climate
data set analyzed nor in situ measurements taken in Greenland support the
range of commonly used spatially and temporally uniform SD values
(~ 5 °C). In this region, the SD distribution is
highly inhomogeneous and characterized by low values during summer months
(~ 1 to 2.5 °C) in areas where most surface melting
occurs. As a result, existing SMB parameterizations using uniform, high SD
values fail to capture both the spatial pattern and amplitude of the
observed surface responses of the GIS. Using realistic SD values enables
significant improvements in the modeled regional and total SMB with respect
to existing estimates from recent satellite observations and the results of
a high-resolution regional model. In addition, this resolves large
uncertainties associated with other major parameters of a PDD model, namely
degree-day factors. The model appears to be nearly insensitive to the choice
of degree-day factors after adopting the realistic SD distribution. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|