Spatial and temporal differences in the effect of forest canopy on snow distribution: a case study in the Spanish Pyrenees
Abstract
Forest canopy strongly influence snow accumulation and melting processes through snowfall interception, enhanced sublimation and alteration of radiative fluxes. However, the total impact of forest canopy on snowpack is highly dependent on dominant climatic conditions, topography and also the trees species and the local structure of the forest stands. All these factors cause spatial and temporal variability in the effect of forest canopy in snow distribution even at very short distances. Such variability has been studies in a forested valley of the Spanish Pyrenees dominated by Pinus uncinata. During three snow seasons (2014-2016) snow depth (SD) and snow water equivalent (SWE) have been manually sampled, and monitored with time-lapse photography, in four sites that exhibits clear differences in elevation, exposition to solar radiation and shape and structure of the forest stands. Results illustrate the complexity of snow accumulation and melting processes in forested areas, and they confirm very large spatial and temporal variability on the effect of forest canopy on snowpack. Thus, reductions of peak SWE in openings vary between 46 and 85%. Differences between areas located beneath canopy and opening are higher during the melting periods, and at the forest stands located at lower elevation. Melting starts earlier beneath canopies in highly irradiated slopes, but the highest melt rates are found in openings at high elevation, where snow lasts for longer. However, the effect of forest canopy on snow melting along the snow season largely depends on the meteorological conditions during the precedent dates. As overall, the effect of forest canopy on snow accumulation (interception) appears more important than the observed differences in melt-rates to explain the spatial and temporal variability of snowpack in the study area. It implies that the structure of the forest stands plays a very important role, which is often overlooked in snow studies, in the snowpack distribution in forested areas.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C51E..06L
- Keywords:
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- 0736 Snow;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 1863 Snow and ice;
- HYDROLOGY