Scenarios of future climatic change: effects on frost occurrence and severity in the maritime uplands of northern England

Changes in annual frost frequency and annual frost accumulation associated with a variety of temperature change scenarios are mapped for northern England. Estimates of future changes are obtained through application of analytical theory to convert predictions of mean daily minimum temperatures and their inter-diurnal variability to accumulated frost degrees and frost frequency. The baseline climate is provided by regression analysis of surface data involving up to ten terrain variables. Future scenarios include warm and cold analogues, maritime and continental airflow scenarios, arbitrary warming and two general circulation model (GCM) simulations: UKHI (United Kingdom Meteorological Office High Resolution GCM Equilibrium Experiment) and GISS (Goddard Institute for Space Studies). Considerable contrasts emerge between scenarios, with substantial reductions in frost frequency and accumulation in the two GCM 2 *CO2 simulations. This is to be expected in a maritime area where small changes in temperature have a large influence on parameters involving threshold temperatures. Increases in frost occur under the continental airflow scenario. Changes in frost do not necessarily complement those in accumulated warmth, and therefore indices combining possible changes in warmth and frost are helpful.