The diurnal cycles of water and energy over North America as simulated by three reanalyses

The diurnal cycle is one of the Earth's fundamental cycles, producing large variations in components of the water and energy budgets; especially at the surface. The diurnal cycles of surface and column-integrated components over North America show similarities and differences among the NCEP/DOE Global Reanalysis-2, the Experimental Climate Prediction Center's Seasonal Forecast Model Reanalysis, and the North American Regional Reanalysis. Despite a wide range of surface properties and climate that affects their diurnal amplitudes over North America, the surface budget components are dominated by geographically common phases owing to particular land-surface schemes and the strength of the diurnal solar signal. Atmospheric components have wider variation. In addition to expected precipitation discrepancies owing to differing convective parameterizations, integrated column budget components undergo strong fluctuations in reservoir tendency dominated by convergence terms. The reanalyses' atmospheric budget components therefore display diverse dynamical responses resulting from regional behaviors including land/sea and mountain/valley circulations as well as a strong influence from low-level jets, all of which are influenced by the spatial resolution of the underlying analysis model.