Theoretical Underpinnings of Snow Interception and Canopy Snow Ablation Parameterisations

Abstract

ABSTRACT In needleleaf forests, up to half of annual snowfall may be returned to the atmosphere through sublimation of snow intercepted in the canopy. However, limited and sparse observations of snow interception and ablation processes have hindered the development of fundamental theories underpinning current estimates of snow accumulation in forests. Existing parameterisations for snow interception and ablation have been developed in locations with distinctive climate, tree species and forest structures, resulting in inconsistent and non‐comprehensive process representations. This variability limits the transferability of these parameterisations across diverse landscapes and climates. Moreover, difficulties in isolating individual processes in field‐based measurements has led to parameterisations that inadvertently coupled multiple processes, adding to uncertainty. Many studies have also simplified original parameterisations and do not include recent advances from observational studies. This review article aims to elucidate the theoretical foundations and assumptions underlying the current snow interception and ablation parameterisations to provide a better understanding of uncertainties in existing methods and identify priorities for future field‐based observational studies. The methods behind snow interception and ablation studies are also reviewed to provide necessary context for examining current parameterisations. Specific gaps in the literature include determining the canopy snow storage capacity, challenges in distinguishing snow throughfall measurements from canopy snow ablation, partitioning unloading rates and canopy snowmelt drainage, the assumption of vertical falling hydrometeor trajectories, the absence of wind resuspension parameterisations, and the limited testing of parameterisations in varied forests and climates.

Topics & Concepts