The Role of Underflows and Weather on Sediment Distribution in Glacial-Fed Lake Linné, Svalbard, Norway
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Climate change is without doubt one of the most problematic issues that society will need to find a solution in the future to prevent further damage. According to the IPCC’s fourth assessment report in 2007, recent climate change has been due to an increase in greenhouse gases caused by humans. Some parts of the world have and will further experience an increase in temperature; this might trigger catastrophic events such as the extinction of polar bears in the arctic regions or desertification in Southwestern US. One way to understand how the Earth will react to this abrupt change is to find out how she has reacted in the past. These past-climate reconstructions are an important key to understand and predict future climatic variations. The High Arctic is currently a vulnerable area being largely affected by climate change. It’s an excellent place to reconstruct past climates due to of its small human population and because it’s completely driven by natural forces. The High-Arctic, especially areas such as Svalbard, will have an increase in temperature of about 8°C by the end of the 21st century (Øseth, 2011). This warming will likely have a huge impact on both local and global plant, animal, and human populations due to the decrease of ice sheets, ice caps, glaciers and snowpack (Øseth, 2011). One of the various proxies presently used to reconstruct past climates are arctic varved lacustrine sediments (Bradley et al., 1996; Overpeck et al., 1997; Lamoureux et al., 2002). Sediments deposited by glacial-fed lakes in the Canadian High-Arctic have received a lot of attention since the late 70s and remain a currently used proxy (Carmack et al., 1979; Smith, 1981; Gilbert and Church, 1983; Smith and Ashley, 1985; Snyder et al., 2000; Lamoureux et al., 2002; Lewis et al., 2002; Cockburn and Lamoureux, 2008, among others). Linnévatnet is an arctic lake monitored by the Svalbard REU since 2003 and contains lacustrine sediments that have laminations which seem to be strongly influenced by season; coarse silt to fine sand in the summer and clay during the winter (Svendsen and Mangerud, 1997; Snyder et al., 2000, McKay, 2004; Motley, 2006; Roop, 2007; Cobin, 2008; Arnold, 2009). Young laminated sediments can be calibrated using current weather data to see how it’s affecting the sediment distribution and use this relationship in older sediments to reconstruct past climate. One factor that influences where and how much sediment will be deposited in an area of a lake is the frequency of different lake processes such as overflows, interflows, underflows and homopycnal flows (described in section (1.3). In Linnévatnet the spring melt occurs during late-June to mid-July. As in other lakes in the Canadian High-Arctic, it is the most important event of the year due to the high input of discharge of nival melt and sediment (Braun, et al. 2000; Gilbert and Butler, 2004; Cockburn and Lamoureux, 2008). The purpose of this project is to determine the frequency of underflows and how they may influence sediment distribution in Linnévatnet. Another goal is to see how underflows are related to weather patterns and inflow temperature during the spring melt. This will be done by using different sets of data gathered from the lake during and a weather station near Linnévatnet during July 2010.