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Estimation of winter leaf area index and sky view fraction for snow modelling in boreal coniferous forests: consequences on snow mass and energy balance

Rasmus, Sirpa ; Gustafsson, David ; Koivusalo, Harri ; Laurén, Ari ; Grelle, Achim ; Kauppinen, Olli-Kalle ; Lagnvall, Ola ; Lindroth, Anders LU ; Rasmus, Kai and Svensson, Magnus , et al. (2013) In Hydrological Processes 27(20). p.2876-2891
Abstract
Abstract in Undetermined
Leaf area index (LAI) and canopy coverage are important parameters when modelling snow process in coniferous forests, controlling interception and transmitting radiation. Estimates of LAI and sky view factor show large variability depending on the estimation method used, and it is not clear how this is reflected in the calculated snow processes beneath the canopy. In this study, the winter LAI and sky view fraction were estimated using different optical and biomass-based approximations in several boreal coniferous forest stands in Fennoscandia with different stand density, age and site latitude. The biomass-based estimate of LAI derived from forest inventory data was close to the values derived from the optical... (More)
Abstract in Undetermined
Leaf area index (LAI) and canopy coverage are important parameters when modelling snow process in coniferous forests, controlling interception and transmitting radiation. Estimates of LAI and sky view factor show large variability depending on the estimation method used, and it is not clear how this is reflected in the calculated snow processes beneath the canopy. In this study, the winter LAI and sky view fraction were estimated using different optical and biomass-based approximations in several boreal coniferous forest stands in Fennoscandia with different stand density, age and site latitude. The biomass-based estimate of LAI derived from forest inventory data was close to the values derived from the optical measurements at most sites, suggesting that forest inventory data can be used as input to snow hydrological modelling. Heterogeneity of tree species and site fertility, as well as edge effects between different forest compartments, caused differences in the LAI estimates at some sites. A snow energy and mass balance model (SNOWPACK) was applied to detect how the differences in the estimated values of the winter LAI and sky view fraction were reflected in simulated snow processes. In the simulations, an increase in LAI and a decrease in sky view fraction changed the snow surface energy balance by decreasing shortwave radiation input and increasing longwave radiation input. Changes in LAI and sky view fraction affected directly snow accumulation through altered throughfall fraction and indirectly snowmelt through the changed surface energy balance. Changes in LAI and sky view fraction had a greater impact on mean incoming radiation beneath the canopy than on other energy fluxes. Snowmelt was affected more than snow accumulation. The effect of canopy parameters on evaporation loss from intercepted snow was comparable with the effect of variation in governing meteorological variables such as precipitation intensity and air temperature. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Hydrological Processes
volume
27
issue
20
pages
2876 - 2891
publisher
John Wiley & Sons Inc.
external identifiers
  • wos:000325218800003
  • scopus:84883265306
ISSN
1099-1085
DOI
10.1002/hyp.9432
language
English
LU publication?
yes
id
e76998b6-12af-43aa-83e1-79ac79af0690 (old id 4155346)
date added to LUP
2016-04-01 10:46:16
date last changed
2022-04-04 21:12:26
@article{e76998b6-12af-43aa-83e1-79ac79af0690,
  abstract     = {{Abstract in Undetermined<br/>Leaf area index (LAI) and canopy coverage are important parameters when modelling snow process in coniferous forests, controlling interception and transmitting radiation. Estimates of LAI and sky view factor show large variability depending on the estimation method used, and it is not clear how this is reflected in the calculated snow processes beneath the canopy. In this study, the winter LAI and sky view fraction were estimated using different optical and biomass-based approximations in several boreal coniferous forest stands in Fennoscandia with different stand density, age and site latitude. The biomass-based estimate of LAI derived from forest inventory data was close to the values derived from the optical measurements at most sites, suggesting that forest inventory data can be used as input to snow hydrological modelling. Heterogeneity of tree species and site fertility, as well as edge effects between different forest compartments, caused differences in the LAI estimates at some sites. A snow energy and mass balance model (SNOWPACK) was applied to detect how the differences in the estimated values of the winter LAI and sky view fraction were reflected in simulated snow processes. In the simulations, an increase in LAI and a decrease in sky view fraction changed the snow surface energy balance by decreasing shortwave radiation input and increasing longwave radiation input. Changes in LAI and sky view fraction affected directly snow accumulation through altered throughfall fraction and indirectly snowmelt through the changed surface energy balance. Changes in LAI and sky view fraction had a greater impact on mean incoming radiation beneath the canopy than on other energy fluxes. Snowmelt was affected more than snow accumulation. The effect of canopy parameters on evaporation loss from intercepted snow was comparable with the effect of variation in governing meteorological variables such as precipitation intensity and air temperature.}},
  author       = {{Rasmus, Sirpa and Gustafsson, David and Koivusalo, Harri and Laurén, Ari and Grelle, Achim and Kauppinen, Olli-Kalle and Lagnvall, Ola and Lindroth, Anders and Rasmus, Kai and Svensson, Magnus and Weslien, Per}},
  issn         = {{1099-1085}},
  language     = {{eng}},
  number       = {{20}},
  pages        = {{2876--2891}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Hydrological Processes}},
  title        = {{Estimation of winter leaf area index and sky view fraction for snow modelling in boreal coniferous forests: consequences on snow mass and energy balance}},
  url          = {{http://dx.doi.org/10.1002/hyp.9432}},
  doi          = {{10.1002/hyp.9432}},
  volume       = {{27}},
  year         = {{2013}},
}