Simulation of snow accumulation and melt in needleleaf forest environments

Abstract

Abstract. Drawing upon numerous field studies and modelling exercises of snow processes, the Cold Regions Hydrological Model (CRHM) was developed to simulate the four season hydrological cycle in cold regions. CRHM includes modules describing radiative, turbulent and conductive energy exchanges to snow in open and forest environments, as well as account for losses from canopy snow sublimation and rain evaporation. Due to the physical-basis and rigorous testing of each module, there is a minimal need for model calibration. To evaluate CRHM, simulations of snow accumulation and melt were compared to observations collected at paired forest and clearing sites of varying latitude, elevation, forest cover density, and climate. Overall, results show that CRHM is capable of characterising the variation in snow accumulation between forest and clearing sites, achieving a model efficiency of 0.51 for simulations at individual sites. Simulations of canopy sublimation losses slightly overestimated observed losses from a weighed cut tree, having a model efficiency of 0.41 for daily losses. Good model performance was demonstrated in simulating energy fluxes to snow at the clearings, but results were degraded from this under forest cover due to errors in simulating sub-canopy net longwave radiation. However, expressed as cumulative energy to snow over the winter, simulated values were 96% and 98% of that observed at the forest and clearing sites, respectively. Overall, the good representation of the substantial variations in mass and energy between forest and clearing sites suggests that CRHM may be useful as an analytical or predictive tool for snow processes in needleleaf forest environments.

Simulating cold-region hydrology in an intensively drained agricultural watershed in Manitoba, Canada, using the Cold Regions Hydrological Model

“…The CRHM platform has been successfully used to simulate hydrological processes in a number of contrasting catchments in Canada (Dornes et al, 2008;Fang and Pomeroy, 2008;Ellis et al, 2010) and globally, in western China (Zhou et al, 2014), Patagonia (Krogh et al, 2015), the German Alps (Weber et al, 2016), and the Spanish Pyrenees (Rasouli et al, 2014), and in the intensively studied South Tobacco Creek watershed that drains from the more steeply sloped Pembina/Manitoba Escarpment feature into the Red River in Manitoba (Mahmood et al, 2017). However, the CRHM has not yet been used to simulate hydrological processes in the intensively managed lowland agricultural tributaries of the Red River such as the La Salle River.…”

LiDAR measurement of seasonal snow accumulation along an elevation gradient in the southern Sierra Nevada, California

“…In dry intercontinental locations, sublimation rates can be in excess of 50 %, but are much lower in the maritime climate of the Sierra Nevada and lowest during the accumulation period (Ellis et al, 2010;Essery and Pomeroy, 2001). Studies conducted at 2800 and 3100 m in the Emerald Lake basin, located in the center of our measurement domain, found net losses due to evaporation and sublimation of < 10 % for the period between 1 December and 1 April .…”

Multi-variable evaluation of hydrological model predictions for a headwater basin in the Canadian Rocky Mountains

“…A lower value of 3.3 kg m −2 was assigned to the young trees in the forest clearing HRU based on field observation that they cannot intercept snow as effectively as mature trees. A higher value of 8.8 kg m −2 was calculated for spruce forest and mixed spruce and lodgepole pine forest HRUs using the method outlined by Ellis et al (2010). The unloading temperature threshold defines the ice bulb temperature above which intercepted snow starts to unload as either snow or liquid water (i.e.…”

“…are described in several recent publications Ellis et al, 2010;MacDonald et al, 2010). Precipitation was measured with an Alter-shielded Geonor weighing precipitation gauge at Hay Meadow, Upper Clearing, and Fisera Ridge and was corrected for wind-induced undercatch (MacDonald and Pomeroy, 2007).…”