Diagnosing diurnal convection signals in the NCEP GFS
In this study, we will examine the diurnal convection signals over the Amazons and the maritime continents using the short-range forecast archives from the NCEP GFS and the climate simulations from the NCEP CFS. The problem with the routine forecast archives is that the output intervals are coarser than we would like to study the diurnal variations. For the GFS, the precipitation bucket is emptied every three hours while the bucket for the CFS simulations is six hours. In order to further diagnose the diurnal signal, we are using a single column version of the GFS to perform short-range predictions and we will composite the forecast products over the warm seasons to compare with the operational archives.
For the oceanic region of the Maritime continents, studies have shown that diurnal convection signal also exists. We will compare the diurnal convective signal over this region from the GFS (which uses observed sea surface temperature) and the CFS (which is a coupled model of the atmosphere and the ocean) to examine the importance of the coupling.