Recent Sedimentation in a High Arctic Glacial Lacustrine System Dominated by Late Melt Season Rain Events, Linnévatnet, Svalbard
Abstract
The annually laminated lacustrine sediment record in proglacial Linnévatnet, Svalbard provides an important long term and high resolution record of hydro-climatic variability in the Norwegian high arctic. Sediment cores recovered from the lake in recent years span the past ca.1,000 years with varves that vary in thickness and structure in response to the amount and timing of sediment delivered by glacifluvial and nival sources. Monitoring watershed and climatological processes has provided the means to directly interpret the annual sedimentation and varves deposited in recent years and will provide the basis for more accurately interpreting the longer term lacustrine record. For the past 13 years, monitoring of the glacial-fluvial-lacustrine system has been facilitated using a network of instrumentation including time lapse cameras, automated weather stations, and moorings in the lake that are equipped with sediment traps, temperature loggers and ctd's. Shorter term hydrological measurements, glacier mass balance measurements and sediment transport studies in the rivers and lake have been undertaken in summer field campaigns. Two general modes of sedimentation have been observed: (1) peak discharge and sedimentation occurring during spring and early summer snow melt, and (2) peak discharge that occurs during late summer and early fall as a result of intense late season rain storms. In 2005, 2006, 2008, 2009, and 2012, the spring nival processes were dominant, however the late season mode was dominant in 4 of the past 5 years (e.g. 2011, 2013, 2014, and 2015). For example, in a 36 hour period in September 2015, approximately 70% of the annual sediment accumulation in sediment traps occurred during this late summer rain event. These storms generally occur when active layer is deepest and sediments are easily mobilized along with residual sediment in stream channels. Continued monitoring efforts will provide insights to the significance of these late season events and how they relate to regional climatological and oceanographic variability in this high arctic setting.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMPP11C2032R
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGEDE: 1833 Hydroclimatology;
- HYDROLOGYDE: 4928 Global climate models;
- PALEOCEANOGRAPHYDE: 4999 General or miscellaneous;
- PALEOCEANOGRAPHY