RELATIVE CONTRIBUTIONS OF LAND AND OCEAN PROCESSES TO PRECIPITATION VARIABILITY

A series of general circulation model simulations are used to quantify the relative contributions of land surface and ocean variability to v ariability in precipitation. The simulations show that land surface pr ocesses contribute significant to the variance of annual precipitation over continents. In contrast, ocean processes acting alone have a muc h smaller effect, particularly in midlatitudes. The precipitation vari ability reflects local evaporation variability and associated hydrolog ical persistence, and it responds most strongly to the land surface du ring summer, when moist convection dominates.