Incorporation of satellite-derived snow-cover area in spatial snowmelt modeling for a large area: determination of a gridded degree-day factor
| Autor: | Yuji Kominami, Yoshihiro Asaoka |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
010504 meteorology & atmospheric sciences
0207 environmental engineering 02 engineering and technology Vegetation Sensible heat Atmospheric sciences Water equivalent Snow 01 natural sciences Degree day Snowmelt Satellite 020701 environmental engineering Geology Snow cover 0105 earth and related environmental sciences Earth-Surface Processes Remote sensing |
| Zdroj: | Annals of Glaciology. 54:205-213 |
| ISSN: | 1727-5644 0260-3055 |
| DOI: | 10.3189/2013aog62a218 |
| Popis: | Spatial degree-day factors (DDFs) are required for spatial snowmelt modeling over large areas by the degree-day method. We propose a method to obtain DDFs by incorporating snow disappearance dates (SDDs), derived from 10 day composites of Satellite Pour l’Observation de la Terre (SPOT)/VEGETATION data, into the degree-day method. This approach allowed determination of DDFs for each gridpoint so as to better reflect regional characteristics than use of spatially constant DDFs obtained from point measurements. Simulations at six observation sites successfully accounted for variations in snow water equivalent (SWE), even at elevations different from the closest measurement site. These results suggest that incorporating satellite-derived SDDs into the degree-day method decreases spatial uncertainty compared with the use of spatially constant DDFs. Application of our method to Japanese cold regions revealed that gridded DDFs were negatively correlated with accumulated positive degree-days (APDDs) and were high only when APDDs were low. These results imply that high DDFs resulted from the dominant contribution of solar radiation to snowmelt at low temperatures and that low DDFs resulted from a relatively high contribution of sensible heat flux at high temperatures. The proposed method seems to adequately account for the main energetic components of snowmelt during the snow-cover season over large areas. |
| Databáze: | OpenAIRE |
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