EPIC-CPPA RHB Radar Rainfall Product Summary

This file describes a series of rainfall products that were generated for model validation as part of the NOAA CPPA initiative.  These products include:

1. Gridded rainfall accumulation for the time period 11 September, 2001 (1511 UTC) - 1 October, 2001 (2301 UTC). There are four separate ascii text files, each one representing the accumulation (mm) using a different Z-R relationship (described below).  The ascii files are named "rhb_cppa_rraccum_zr.txt", where "zr" is the acronym for the Z-R relation used (described below).  The gridded domain extends 100 km in all directions (i.e.,  north south, east and west) from the nominal position of the RHB radar (10N, 95W).  The spacing of the grid points is 2 km.  Each line of the data are written out using a print statement 101(f6.1,2x). Each line of these files represents a "y" position (N-S) in the gridded domain.  The 101 data points in each line are the "x" position (E-W) values.  So, the first value in the first line represents data at the lower left corner of the domain (i.e., SW corner) and the remaining values in that first line represent data running eastward along the southern end of the domain.  The next line is 2km north of the first line and so forth.  

2. Image (png) files of rainfall accumulation for the time period specified above. The files are named "rhb_cppa_rraccum_zr.png", where "zr" is the acronym for the Z-R relation used (described below).  

3. An ascii text file for each Z-R relation specifying some basic rain rate statistics for each radar volume of the data set.  The ascii files are named "rhb_cppa_rrstats_zr.txt", where "zr" is the acronym for the Z-R relation used (described below).  In each ascii file, there are 3 lines for each radar volume time:

   * date/time stamp in UTC
   * mean, median and maximum rain rate over the domain (mm/hr)
   * histogram of rain rate (start_bin=0.1(mm/hr), interval=2.0(mm/hr), and nbins=50).  These data are written out using  a print statement 50(i8).

4. 2 files (lat_cppa.txt and lon_cppa.txt) which specify the corresponding lon/lat positions of the x,y grid for the accumulations.  These positions were written out using a simple flat earth approximation.  Each line of the data are written out using a print statemnt: (101(f9.5,1x)).

The 4 Z-R relations used include:

1. GATE (gt): Z=230R^1.25 (Hudlow, 1978)
2. EPIC C130 (c1): Z=218R^1.60 (Baumgardner C-130 insitu data)
3. RHB-TAO (rt): Z=132R^1.24 (comparison RHB radar reflectivity over TAO buoy measured rain rate)
5. TRM-PR (pr): Z=222R^1.35 (analysis of TRMM PR over EPIC domain 1998-2004 J,A,S)