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| Titel |
A correction factor for positive degree-day modeling of ice sheet surface melt under changing orbital configurations |
| VerfasserIn |
Alexander Robinson, Heiko Goelzer, Philippe Huybrechts |
| 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 |
250078920
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| Zusammenfassung |
| Positive degree-day (PDD) models have commonly been used to approximate continental ice sheet surface melt for the last two decades. The approach is advantageous in that it approximates present-day surface melt reasonably well and it is computationally very efficient. However, the empirical coefficients used to translate PDDs into melt are tuned to present-day conditions and thus may not be appropriate for use under other orbital configurations.
Here we explore to what extent the current formulation of a PDD melt equation affects melt estimates for different levels of orbital-scale insolation changes. We find that insolation anomalies can cause large discrepancies between melt calculated using PDDs and using a simple energy-balance equation. However, higher temperatures reduce the effect of the insolation anomaly since its relative importance decreases in the energy balance. We introduce a correction factor for the PDD model that accounts for changes in insolation and improves the agreement of melt estimated by the two different methods. A particular feature of this factor is that it is fully consistent with current PDD models for present-day insolation. The new insolation-corrected PDD formulation is further tested with transient simulations of the Greenland ice sheet for the Eemian. |
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