Estimating degree-day factors of snow based on energy flux components
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Published:2023-01-17
Issue:1
Volume:17
Page:211-231
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ISSN:1994-0424
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Container-title:The Cryosphere
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language:en
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Short-container-title:The Cryosphere
Author:
Ismail Muhammad FrazORCID, Bogacki WolfgangORCID, Disse MarkusORCID, Schäfer Michael, Kirschbauer Lothar
Abstract
Abstract. Meltwater from mountainous catchments dominated by snow and ice is a valuable source of fresh water in many regions. At mid-latitudes, seasonal snow cover and glaciers act like a natural reservoir by storing precipitation during winter and releasing it in spring and summer. Snowmelt
is usually modelled either by energy balance or by temperature-index
approaches. The energy balance approach is process-based and more
sophisticated but requires extensive input data, while the temperature-index approach uses the degree-day factor (DDF) as a key parameter to estimate melt of
snow and ice merely from air temperature. Despite its simplicity, the
temperature-index approach has proved to be a powerful tool for simulating
the melt process especially in large and data-scarce catchments. The present study attempts to quantify the effects of spatial, temporal, and climatic conditions on the DDF of snow in order to gain a better understanding of which influencing factors are decisive under which conditions. The analysis is based on the individual energy flux components; however, formulas for estimating the DDF are presented to account for situations where observed data are limited. A detailed comparison between field-derived and estimated DDF values yields a fair agreement with bias = 0.14 mm ∘C−1 d−1 and root mean square error (RMSE) = 1.12 mm ∘C−1 d−1. The analysis of the energy balance processes controlling snowmelt indicates
that cloud cover and snow albedo under clear sky are the most decisive
factors for estimating the DDF of snow. The results of this study further
underline that the DDF changes as the melt season progresses and thus also with altitude, since melting conditions arrive later at higher elevations. A brief analysis of the DDF under the influence of climate change shows that the DDFs are expected to decrease when comparing periods of similar degree days, as melt will occur earlier in the year when solar radiation is lower, and albedo is then likely to be higher. Therefore, the DDF cannot be treated as a constant
parameter especially when using temperature-index models for forecasting
present or predicting future water availability.
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
Reference107 articles.
1. Ahmad, M. J. and Tiwari, G. N.: Solar radiation models-A review, Int. J.
Energy Res., 35, 271–290, https://doi.org/10.1002/er.1690, 2011. 2. Allen, R. G., Pereira, L. S., Raes, D., and Smith, M.: Crop
evapotranspiration – guidelines for computing crop water requirements, FAO Irrigation and Drainage Paper 56, FAO, Rome,
Italy, 300 pp., 1998. 3. Amaral, T., Wake, C. P., Dibb, J. E., Burakowski, E. A., and Stampone, M.: A
simple model of snow albedo decay using observations from the Community
Collaborative Rain, Hail, and Snow-Albedo (CoCoRaHS-Albedo) Network, J.
Glaciol., 63, 877–887, https://doi.org/10.1017/jog.2017.54, 2017. 4. Ambach, W.: Characteristics of the Heat Balance of the Greenland Ice sheet
for Modelling, J. Glaciol., 31, 3–12,
https://doi.org/10.3189/S0022143000004925, 1985. 5. Anderson, E. A.: National Weather Service river forecast system-snow accumulation
and ablation model. National Oceanographic and Atmospheric Administration (NOAA), Tech.
Mem., NWS
HYDRO-17, US Dept. of Commerce, Silver Spring, MD, 217 pp.,
https://repository.library.noaa.gov/view/noaa/13507 (last access: 3 January 2023), 1973.
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