Simulated single-layer forest canopies delay Northern Hemisphere snowmelt

Todt, Markus, Rutter, Nick, Fletcher, Christopher and Wake, Leanne (2019) Simulated single-layer forest canopies delay Northern Hemisphere snowmelt. The Cryosphere. ISSN 1994-0416 (In Press)

Todt et al - Simulated single-layer forest canopies delay Northern Hemisphere snowmelt AAM.pdf - Accepted Version
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Single-layer vegetation schemes in modern land surface models have been found to overestimate diurnal cycles in longwave radiation beneath forest canopies. This study introduces an empirical correction, based on forest stand-scale simulations, which reduces diurnal cycles of sub-canopy longwave radiation. The correction is subsequently implemented in land-only simulations of the Community Land Model version 4.5 (CLM4.5) in order to assess the impact on snow cover. Nighttime underestimations of sub-canopy longwave radiation outweigh daytime overestimations, which leads to underestimated averages over the snow cover season. As a result, snow temperatures are underestimated and
snowmelt is delayed in CLM4.5 across evergreen boreal forests. Comparison with global observations confirms this delay and its reduction by correction of sub-canopy longwave radiation. Increasing insolation and day length change the impact of overestimated diurnal cycles on daily average subcanopy longwave radiation throughout the snowmelt season. Consequently, delay of snowmelt in land-only simulations is more substantial where snowmelt occurs early.

Item Type: Article
Uncontrolled Keywords: snow, longwave radiation, forest structure, Land surface modelling, climate modeling
Subjects: F800 Physical and Terrestrial Geographical and Environmental Sciences
Department: Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User: Paul Burns
Date Deposited: 09 Oct 2019 11:06
Last Modified: 11 Oct 2019 13:56

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