POLAR TEMPERATURE SENSITIVITY TO LUNAR FORCING

Climate models and paleoclimatic evidence suggest that the earth's pol ar regions are particularly responsive to global scale climatic forcin g. Empirical climatological evidence of the last century has thus far failed to confirm conclusively this regional sensitivity. We conduct a n empirical study of polar sensitivity to climate forcing by comparing a high-quality, 17-year satellite-derived dataset of daily temperatur es for 2.5 degrees latitudinal bands to a known external forcing mecha nism, the lunar phase cycle. The earth's polar regions display a tempe rature range of greater than 0.55 degrees C over the course of a synod ic (29.53 day) month. This lunar-influenced range in temperature is 25 times larger than a similarly computed range in aggregated global tem peratures over a synodic month. Temperature variations between the pol ar and non-polar regions also produce a pronounced temporal shift in s ensible heat transfer. Strong poleward transfer of heat dominates near the full moon but the transfer substantially weakens near the new moo n. It is unlikely that this sensitivity can be explained by the type o f polar forcing previously identified in GCM simulations and paleoclim atic reconstructions, because of the short duration of the lunar cycle . However, it does demonstrate it new and potentially important extern al influence on the polar regions' climates.