Using digital photos and models to analyze episodic winter snowmelt events in low-Arctic ecosystems
Abstract
Terrestrial snow cover is a key parameter controlling both abiotic and biotic ecosystem processes in the Arctic. Yet knowledge and observations of snow cover in Greenland are limited. However, one exception is Kobbefjord (64°07'N, 51°21'W) in West Greenland. Since 2007, Nuuk Ecological Research Operations (NERO), led by Greenland Ecosystem Monitoring, have run an ecosystem baseline monitoring program responsible for collecting extensive snow observation datasets using manual, automated, and remotely-sensed methods. The available snow datasets provide a unique opportunity to describe and analyze the spatial and temporal distribution of snow-cover features and interactions in a low-Arctic setting where snow-dependent ecosystem components and processes are also observed. The aim of this study is to understand the temporal and spatial snow evolution in a low-Arctic ecosystem where a range of validation data is available, with a particular emphasis on infrequent winter snowmelt events. Extreme winter melt events associated with air temperatures rising abruptly to above 0.0 °C and with wind speeds greater than 20 m/s have been observed. We identified these melt events and quantified their effect on the snowpack and water balance to address possible consequences for a range of biological parameters. Finally, we compared the inter-annual air temperature variation during the last five years (2007-2013) with a 119-year climate record to place these recent variations within a long-term climate perspective. We implemented a spatially distributed snow-evolution modeling system (SnowModel) to provide temporal and spatial descriptions of snow within the study area from 2007 through 2013. SnowModel was driven by climate data collected by NERO. The available snow observations enabled validation of the modeled snow depth through 1) independent manual and automated snow depth measurements, and 2) a spatial validation of the modeled snow cover depletion through snow classification of daily digital photos acquired by automated cameras overviewing the study area. From the model outputs, nine winter melt events were identified during 2007-2013. These were confirmed by daily digital photos in which changes in snow coverage were visible. A melt event in October 2008 generated 144 mm of winter runoff, which equals 14 % of the total annual precipitation; this represents moisture that was unavailable to soil and ecosystem processes during the following year's growing season. This highlights the importance of these episodic winter melt events in the low-Arctic ecosystem. The 119-year climate record showed an increasing trend (higher values) in minimum, mean, and maximum air temperatures. If this trend continues, the frequency of melt events will increase, with dramatic consequences for Arctic ecosystems.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.C41B0613P
- Keywords:
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- 0736 CRYOSPHERE Snow;
- 0740 CRYOSPHERE Snowmelt;
- 0758 CRYOSPHERE Remote sensing;
- 9315 GEOGRAPHIC LOCATION Arctic region