The rainrate data is available as compressed ascii files with the following format:
x,y,rr,method
where x,y are relative to S-pol origin in km, rr=rainrate (mm/hr) and method is the polimetric technique that was used to compute the rainrate. For more information of how the rainrates were computed look at this web page or PDF file.
They are available here and in a compressed tar archive
Note: Before 14 November 2003 the x (E/W) and the y (N/S) was switched, so before 14 November 2003 the data was formatted as y,x,rr,method. It has been corrected.