Paper in Press
GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2012GL052794
Projected decline in spring snow depth on Arctic sea ice caused by progressively later autumn open ocean freeze-up this century
- Autumn loss of sea ice causes decline in snow depths on Arctic ice in 21 century
- Snow depths fall below threshold needed for snow caves for ringed seal rearing
- Increase in rainfall rates is likely to further diminish snow depths
We present the first analysis of snow depths on Arctic sea ice in the Coupled Model Intercomparison Project 5 (CMIP5) because of its importance for sea ice thermodynamics and ringed seal ({\it Phoca hispida}) habitat. Snow depths in April on Arctic sea ice decrease over the 21st century in RCP2.6, RCP4.5, and RCP8.5 scenarios. The chief cause is loss of sea ice area in autumn and, to a lesser extent, winter. By the end of the 21st century in the RCP8.5 scenario, snowfall accumulation is delayed by about three months compared to the late 20th century in the multi-model mean. Mean April snow depth north of 70$^\circ$N declines from about 28 cm to 16 cm. Precipitation increases as expected in a warmer climate, but much of this increase in the Arctic occurs as rainfall. The seasonality of snowfall rate grows, with increasing rates in winter and decreasing rates in summer and autumn, but the cumulative snowfall from September to April does not change. Ringed seals depend on spring snow cover on Arctic sea ice to create subnivean birth lairs. The area with snow depths above 20 cm --- a threshold needed for ringed seals to build snow caves --- declines by 70\%.
Received 19 June 2012; accepted 5 August 2012.
Citation: (2012), Projected decline in spring snow depth on Arctic sea ice caused by progressively later autumn open ocean freeze-up this century, Geophys. Res. Lett., doi:10.1029/2012GL052794, in press.