A Tiling Approach to Represent Subgrid Snow Variability in Coupled Land Surface–Atmosphere ModelsSource: Journal of Hydrometeorology:;2016:;Volume( 018 ):;issue: 001::page 49DOI: 10.1175/JHM-D-16-0026.1Publisher: American Meteorological Society
Abstract: mosaic approach to represent subgrid snow variation in a coupled atmosphere?land surface model (WRF?Noah) is introduced and tested. Solid precipitation is scaled in 10 subgrid tiles based on precalculated snow distributions, giving a consistent, explicit representation of variable snow cover and snow depth on subgrid scales. The method is tested in the Weather Research and Forecasting (WRF) Model for southern Norway at 3-km grid spacing, using the subgrid tiling for areas above the tree line. At a validation site in Finse, the modeled transition time from full snow cover to snow-free ground is increased from a few days with the default snow cover fraction formulation to more than 2 months with the tiling approach, which agrees with in situ observations from both digital camera images and surface temperature loggers. This in turn reduces a cold bias at this site by more than 2°C during the first half of July, with the noontime bias reduced from ?5° to ?1°C. The improved representation of subgrid snow variation also reduces a cold bias found in the reference simulation on regional scales by up to 0.8°C and increases surface energy fluxes (in particular the latent heat flux), and it resulted in up to 50% increase in monthly (June) precipitation in some of the most affected areas. By simulating individual soil properties for each tile, this approach also accounts for a number of secondary effects of uneven snow distribution resulting in different energy and moisture fluxes in different tiles also after the snow has disappeared.
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contributor author | Aas, Kjetil Schanke | |
contributor author | Gisnås, Kjersti | |
contributor author | Westermann, Sebastian | |
contributor author | Berntsen, Terje Koren | |
date accessioned | 2017-06-09T17:17:02Z | |
date available | 2017-06-09T17:17:02Z | |
date copyright | 2017/01/01 | |
date issued | 2016 | |
identifier issn | 1525-755X | |
identifier other | ams-82380.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4225487 | |
description abstract | mosaic approach to represent subgrid snow variation in a coupled atmosphere?land surface model (WRF?Noah) is introduced and tested. Solid precipitation is scaled in 10 subgrid tiles based on precalculated snow distributions, giving a consistent, explicit representation of variable snow cover and snow depth on subgrid scales. The method is tested in the Weather Research and Forecasting (WRF) Model for southern Norway at 3-km grid spacing, using the subgrid tiling for areas above the tree line. At a validation site in Finse, the modeled transition time from full snow cover to snow-free ground is increased from a few days with the default snow cover fraction formulation to more than 2 months with the tiling approach, which agrees with in situ observations from both digital camera images and surface temperature loggers. This in turn reduces a cold bias at this site by more than 2°C during the first half of July, with the noontime bias reduced from ?5° to ?1°C. The improved representation of subgrid snow variation also reduces a cold bias found in the reference simulation on regional scales by up to 0.8°C and increases surface energy fluxes (in particular the latent heat flux), and it resulted in up to 50% increase in monthly (June) precipitation in some of the most affected areas. By simulating individual soil properties for each tile, this approach also accounts for a number of secondary effects of uneven snow distribution resulting in different energy and moisture fluxes in different tiles also after the snow has disappeared. | |
publisher | American Meteorological Society | |
title | A Tiling Approach to Represent Subgrid Snow Variability in Coupled Land Surface–Atmosphere Models | |
type | Journal Paper | |
journal volume | 18 | |
journal issue | 1 | |
journal title | Journal of Hydrometeorology | |
identifier doi | 10.1175/JHM-D-16-0026.1 | |
journal fristpage | 49 | |
journal lastpage | 63 | |
tree | Journal of Hydrometeorology:;2016:;Volume( 018 ):;issue: 001 | |
contenttype | Fulltext |