Suvarchal Kumar Cheedela Single Column Models

Low cloud feedbacks are explored using a hierarchy of general circulation model (GCM) configurations. First, the sensitivity of equilibrium solutions of the ECHAM6 Single Column Model (SCM) for two idealized low cloud regimes, stratocumulus and shallow cumulus in the Northeast Pacific is investigated. The results show that an idealized large scale forcing constant in time can produce multiple solu-tions that are not necessarily representaive of solutions with more realistic nature of large scale forcing. The ability of the SCM to predict changes in low clouds of a GCM is explored across a heirarchy of configurations of the MPI-ESM model family, including fully coupled experiments with abrupt changes in CO2, AMIP configurations forced by changes in the sea-surface temperature, and Aquaplanet configurations forced similarly to the AMIP simulations. For these purposes shallow cumulus and stra-tocumulus regimes are defined based on the large scale state. It is found that the clouds in comprehensive configurations respond differently than in the ideal