East-West Asymmetry in Coastal Temperatures of Hudson Bay as a Proxy for Sea Ice
Hudson Bay experiences a complete cryogenic cycle, which has been well documented since 1971. We developed a temperature proxy method to extend the sea ice record back to 1944, using mean temperatures for Churchill and Inukjuak and the difference between these means at two different seasonal periods. This method proved to reproduce the 1971 to 2011 ice-free season length record with an error just over eight days (6%). This relationship was used to hindcast ice-free season length to 1944. This hindcast was subsequently appended to the existing 1971–2011 record to form a 68-year sea ice record. This extended record shows that the recent statistically significant increase in length of the ice-free season was not the result of a natural oscillation of less than 68 years and is consistent with a net warming due to increasing greenhouse gases.