The links within this page point to histogram plots illustrating the number of observations at a station with respect to the elevation angle of the satellite. The division between each histogram is two degrees in elevation. These figures were created using the observations from January 25, 2001.
While these plots show all the observations that are tracked, only the observations that are above 10 degrees elevation angle are currently processed. We are considering a modification in the analysis parameters that would lower this elevation mask.