3:30 PM - 3:45 PM
[ACC29-13] Seasonal climate variations and climate-vegetation feedbacks in the northern high latitude driven by obliquity and precession
Keywords:orbital parameter, glacial cycles, climate feedback
An Atmosphere-Ocean-Vegetation GCM (O’ishi and Abe-Ouchi, 2011) with various combinations of realistic orbital parameters (maximum, minimum and present values for each parameter) is used to investigate the summer temperature changes. A seasonal feedback analyses method (Lu and Cai, 2009) is then applied to the results.
Results show that the summer temperature change across the land induced by obliquity changes is much larger than that induced by precession-eccentricity changes, in spite of the similar magnitude of summer insolation changes. It is suggested that a larger obliquity promotes vegetation-snow-albedo feedbacks in spring, especially with a northward shift of the tundra-forest boundary, amplifying the warming at high northern latitudes throughout the year, and a precise consideration of the combinations of the orbital parameters is needed to improve our understanding of glacial cycles.