A synthetic ice core approach to estimate ion relocation in an ice field site experiencing periodical melt: a case study on Lomonosovfonna, Svalbard

Carmen P. Vega, Veijo A. Pohjola, Emilie Beaudon, Björn Claremar, Ward J. J. van Pelt, Rickard Pettersson, Elisabeth Isaksson, Tõnu Martma, Margit Schwikowski, Carl E. Bøggild
2016 The Cryosphere  
<p><strong>Abstract.</strong> Physical and chemical properties of four different ice cores (LF-97, LF-08, LF-09 and LF-11) drilled at Lomonosovfonna, Svalbard, were compared to investigate the effects of meltwater percolation on the chemical and physical stratigraphy of these records. A synthetic ice core approach was employed as reference record to estimate the ionic relocation and meltwater percolation length at this site during the period 2007–2010. Using this method, a partial ion elution
more » ... rtial ion elution sequence obtained for Lomonosovfonna was NO<sub>3</sub><sup>−</sup><span class="thinspace"></span>&amp;gt;<span class="thinspace"></span>SO<sub>4</sub><sup>2−</sup>, Mg<sup>2+</sup>, Cl<sup>−</sup>, K<sup>+</sup>, Na<sup>+</sup> with nitrate being the most mobile within the snowpack. The relocation length of most of the ions was on the order of 1<span class="thinspace"></span>m during this period. In addition, by using both a positive degree day (PDD) and a snow–energy model approaches to estimate the percentage of melt at Lomonosovfonna, we have calculated a melt percentage (MP) of the total annual accumulation within the range between 48 and 70<span class="thinspace"></span>%, for the period between 2007 and 2010, which is above the MP range suggested by the ion relocation evidenced in the LF-syn core (i.e., MP<span class="thinspace"></span> = <span class="thinspace"></span>30<span class="thinspace"></span>%). Using a firn-densification model to constrain the melt range, a MP of 30<span class="thinspace"></span>% was found over the same period, which is consistent with the results of the synthetic ice core approach, and a 45<span class="thinspace"></span>% of melt for the last 60 years. Considering the ionic relocation lengths and annual melt percentages, we estimate that the atmospheric ionic signal remains preserved in recently drilled Lomonosovfonna ice cores at an annual or bi-annual resolution when weather conditions were similar to those during the 2007–2010 period.</p>
doi:10.5194/tc-10-961-2016 fatcat:vk46iaz32jd2xfd37mybeaptiu