Seasonal, synoptic, and intraseasonal variability of the West African monsoon in the superparameterized-CCSM

The simulation of the West African monsoon is examined in both the standard Community Climate System Model (CCSM), which uses traditional convective parameterizations and the superparameterized-CCSM (SP-CCSM), in which convective parameterizations have been replaced by embedding a two-dimensional cloud resolving model into each gridbox. Key features of West African climate are analyzed in both models including: the mean annual cycle of the monsoon, African easterly wave (AEW) activity, and intraseasonal variability of precipitation. Adding superparameterization improves the position and intensity of summer precipitation which is shifted from over the Gulf of Guinea in CCSM (not realistic), to over the continent in SP-CCSM. AEWs and their relationship with convection are also improved in the SP-CCSM: Limited wave activity is found in the standard model while the SP-CCSM produces strong AEWs that exhibit similar dynamical structures to observations. The coupling between AEWs and convection is stronger in SP-CCSM than observed. Consistent with observations, intraseasonal variations in West African precipitation in SP-CCSM may be linked to convection in the Indo-Pacific region corresponding with the MJO and Indian monsoon. SP-CCSM has potential to deepen our understanding of teleconnections between the MJO and West Africa.

About the presenter
Presenter(s): 
Rachel McCrary
Where
Room: 
Main Seminar Room
When
Date and time: 
Tuesday, December 11, 2012 - 3:30pm