Variability of Arctic climate and sea ice over the past millennium: implications for ice cap mass balance

Core chronology will be established by a number of techniques. The primary basis for annual layer recognition will be measurements of δ¹⁸O. Independent assessment of the validity of the δ¹⁸O annual layer chronology can be provided by the identification of known age marker horizons e.g. the 1963 "bomb layer" (located by in-situ ¹³⁷Cs-gamma spectrometry in the borehole); volcanic eruptions such as Laki 1783; the large bi-hemispheric eruption in 1259 AD; Katmai (1912 AD) and probably Tambora (1816 AD) (identifiable as peaks in the EC and sulfate concentration records). In addition, a series of snow chemistry samples across PoW are used to constrain the seasonal variation in snow ion chemistry (see Sharp, Skidmore and Nienow, 2002) so that the chemical stratigraphy of the core can be used to identify annual and sub-annual layers on the basis of known seasonal peaks in individual species.

The high rate of accumulation at the proposed core site should allow us to use annual layers to derive an exact chronology for the cores for the past 1000 years. As this has not been achieved for any previous Canadian ice core, a precisely dated core such as this will greatly facilitate correlation of data from this project with those from elsewhere in the Arctic.

A major component of this project is to produce a regional synthesis of pan-Arctic ice core proxies, to provide a regional view of climate patterns and their relationship with sea ice and glacier mass balance.