NASA - National Aeronautics and Space Administration

High-resolution (0.1x0.1
) geostationary satellite infrared radiances at 11 mm in combination with gridded (2.5x2.0
) hourly surface precipitation observations are employed to document the spatial structure of the diurnal cycle of summertime deep convection and associated precipitation over North America. Comparison of the diurnal cycle pattern between the satellite retrieval and surface observations demonstrates the reliability of satellite radiances for inferring the diurnal cycle of precipitation, especially the diurnal phase. On the basis of the satellite radiances, we find that over most land regions, deep convection peaks in the late afternoon and early evening, a few hours later than the peak of land surface temperature. However, strong regional variations exist in both the diurnal phase and amplitude, implying that topography, land-sea contrast, and coastline curvature play an important role in modulating the diurnal cycle. Examples of such effects are highlighted over Florida, the Great Plains, and the North American monsoon region.