RADIATION WINDOWS AS INDICATORS OF AN ASTRONOMICAL INFLUENCE ON THE DEVILS HOLE CHRONOLOGY

Orbital explanations of paleoclimatic records traditionally focus on d aily insolation at similar to 60 degrees N. We exemplify how insolatio n at different latitudes and different times of day can explain the ti ming of the Devil's Hole delta(18)O record. We combine winter tropical noontime insolation (associated with the source-region for wintertime precipitation) and summer extra-tropical noontime insolation (produci ng noontime heat to warm terrestrial surfaces). Periods of low winter and high summer insolation are called ''radiation windows'' and yield drier-warmer conditions in the Northern Hemisphere mid-latitudes. When radiation windows are compared with the DH-11 record, the apparent co ntradiction with Milankovitch (Winograd et al., 1992) may be resolved. The middle-latitude continental climate signal, as recorded by DH-11, tends toward a cooling state until interrupted by a termination. In e very instance where the DH-11 record is warming before a radiation win dow, a termination occurs. If radiation windows occur with antecedent cooling, then there is a complex response of warming with a variable l ag effect. Yet, there are no cases where cooling follows a radiation w indow.