Abstract Author: Min Wen, Song Yang, Augustin Vintzileos, and Wayne Higgins
Abstract Title: Impacts of Model Resolutions and Initial Conditions on Predictions of the Onset of Asian Summer Monsoon by the NCEP CFS
Abstract: A series of 60-day hindcasts by the NCEP Climate Forecast System was analyzed to understand the impacts of model resolutions and initial conditions on predicting the Asian summer monsoon. The experiments, from 2002 to 2006 and with 14 ensemble members, were conducted at resolutions of T62, T126, and T254. They were initialized every five days from May to August, using the operational global atmospheric data assimilation system and the operational global ocean data assimilation.
It is found that, in predicting the magnitude and timing of monsoon rainfall over lands, high resolutions perform better than lower resolutions. The increase in prediction skills with resolutions is more evident over South Asia than over Southeast Asia. The largest improvement is seen over the Tibetan Plateau. However, the increase in model resolutions does not enhance the skill of monsoon predictions over oceans. It is also found that model resolutions have larger impacts than initial conditions on predicting the onset of monsoons.