Atmospheric predictability of seasonal climate means: Sensitivity to annual cycle and ENSO variations

The role of annual cycle phase and ENSO variations over atmospheric predictability of seasonal climate over the Pacific-North American (PNA) and Asian Monsoon regions is discussed. It was found that the atmospheric predictability on seasonal time scale depends on slowly varying anomalous lower boundary forcing, which effects the atmospheric development. The potential predictability was measured using ensembled of climate simulations. It is believed that lower boundary conditions dominate interannual variability in the tropics and monsoon systems. Signal to noise ratio measurement over the Asian/Pacific monsoon region shows a prominant sea level pressure anomaly during the warm climate.