At intradiurnal time scales, the model captures the amplitude and phase of the diurnal harmonic over both land and sea. The largest amplitudes occur over the summer continents, with contrasting phases of maximum OLR depending on the presence of convective activity. Over the oceans, the model show a coherent structure to the diurnal cycle associated with regions of convection.
Analysis of synoptic (2 to 10 days) and low frequency (greater than 10 days) variability shows that in many instances the model agrees well with observations. For both seasons, the model simulates westward moving phenomena over the oceans whose phase speed is reasonable. In July, these easterly waves display well-defined periodicities in agreement with observations, whilst in January they are more episodic. Low frequency variability is more prevalent in January, particularly over the convectively active regions of the eastern hemisphere. In general, this variability has a larger spatial scale than synoptic variability; its periodicities, some in excess of 30 days, are typical of intraseasonal time scales. (pdf file)
UCRL-MI-123395