Comment on "Weekly precipitation cycles? Lack of evidence from United States surface stations'' by D. M. Schultz et al.

Schultz et al. (2007) (hereinafter referred to as S07) recently published the results of their search for a weekly cycle in U. S. rain-gauge measurements, claiming that their null results contradict those of a study (unpublished at the time) by Bell et al. (2008) (hereinafter referred to as B08) of satellite and rain-gauge data. S07 failed to note 1) that the satellite results described by B08 were for the years 1998 and after, whereas their data ended in 1992, and 2) that the analysis by B08 of rain- gauge data for the years studied by S07 were consistent with their conclusions. B08 in fact show that the weekly cycle in rainfall over the SE U. S. becomes detectable after about 1990. We discuss the methods used by S07. We suggest that a more focused approach-if guided by physical theory-can extract far more useful information from a dataset than generic statistical searches such as described by S07.