Toward understanding the large-scale land-atmosphere coupling in the models: Roles of different processes

Abstract

Two different Atmospheric General Circulation Models (AGCMs), each coupled to three different land surface schemes (LSSs) (six different model configurations in total), are used to study the roles of different model components and different action processes in land-atmosphere coupling. Experiments show that, for the six model configurations, the choice of AGCMs is the main reason for the substantially different precipitation variability, predictability, and land-atmosphere coupling strength among the configurations. The impact of different LSSs is secondary. Intraseasonal precipitation variability, which is mainly a property of the AGCM, can impact land-atmosphere coupling both directly in the atmosphere and indirectly through soil moisture response to precipitation. These results lead to a common conceptual decomposition of the land-atmosphere coupling strength and increases the understanding on large-scale land-atmosphere coupling. © 2010 by the American Geophysical Union.