Dependence of Satellite Sampling Error on Monthly Averaged Rain Rates:Comparison of Simple Models and Recent Studies

Abstract

Abstract Considerable progress has been made in recent years with using satellite data to generate maps of rain rate with grid resolutions of 1°–5° square. In parallel with these efforts, much work has been devoted to the problem of attaching error estimates to these products. There are two main sources of error, the intrinsic errors in the remote sensing measurements themselves (retrieval errors) and the lack of continuity in the coverage by low earth-orbiting satellites (sampling error). Perhaps a dozen or so studies have attempted to estimate the sampling-error component. These studies have been based on rain gauge and radar-derived data, and the estimates vary so much that it is clear that the sampling error cannot be represented satisfactorily by a single value. These studies are reviewed. Some of the results reported in these studies are based on a method referred to in this paper as “resampling by shifts.” The authors find that the method unfortunately tends to produce estimates that are subject to...