Snow and ice facies variability and ice layer formation on Canadian Arctic ice caps, 1999-2005

Time series of enhanced resolution data from the SeaWinds scatterometer aboard QuikScat were used to map the distribution of snow and ice surface facies and ice layer formation in the percolation zone on ice caps in the Queen Elizabeth Islands during the period 1999-2005. Iterative Self-Organizing Data Analysis classification of the mean postfreeze-up biweekly average sigma(0) signal for the 7-year period resulted in the delineation of four snow and ice surface facies (interpreted as the percolation, saturation, superimposed ice, and glacier ice zones). Analysis with National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis reveals that changes in geopotential height in the troposphere (700, 500, and 300 hPa) and air temperature (700 hPa level) are positively (negatively) correlated with area changes in the glacier ice (percolation and saturation) zones and changes in facies boundary elevation. The change in biweekly-averaged backscatter following the freeze-up periods between successive autumns was used to map changes in the distribution of ice layers formed by meltwater percolation and refreezing in the snowpack within the percolation zone. Strongly positive air temperature anomalies at the 700 hPa level in 2001 and 2005 are consistent with extensive ice layer formation in the percolation zones of all ice caps. Such large interannual changes in ice layer formation are likely associated with large changes to the density profile of the snowpack and may be associated with surface elevation changes that are unrelated to changes in surface mass balance.