How well can we parameterize past accumulation rates in polar ice sheets?

An important component of models of the cryosphere is the calculation of accumulation rates over polar ice sheets. As a first-order approximation, many models rely on the assumption that temperature is the main controlling factor for precipitation. However, compilation of available ice-core data, including a new core from Taylor Dome East Antarctica. suggests that precipitation is significantly decoupled from temperature for a large proportion of both the Greenland and Antarctic ice sheets. While the estimated glacial-to-interglacial change in temperature does not differ greatly among ice cores from each ice sheet, the estimated change in accumulation rate var ies by more than a factor of 2. A simple vapor-pressure parameterization gives reasonable estimates of accumulation in the ice-sheet interior; but this is not necessarily the case close to the ice-sheet margin, where synoptic weather systems are important.