A varve record of increased 'Little Ice Age' rainfall associated with volcanic activity, Arctic Archipelago, Canada

Varved sediments from Nicolay Lake, Canadian High Arctic, record major summ er rainfall events over the last five centuries. Increased incidences of su mmer rainfall occurred during the coldest periods of the 'Little Ice Age' a nd were strongly clustered in the years immediately following major volcani c events. Comparison of the summer rainfall and proxy air temperature recor ds thus provides a fuller understanding of the nature and causes of natural climate variability in the Arctic. Study of the synoptic conditions associ ated with the two most recent large summer rainfall events suggests that th ey are associated with the incursion of cold low-pressure systems from the Arctic Ocean Basin. Volcanic activity may produce atmospheric conditions mo re conducive to the formation of such low-pressure systems, which generate rainfall at low elevations and summer snowfall at higher elevations, thus e xplaining the correlation between rainfall and summer snow accumulation rec orded in ice cores from high-elevation ice caps.