date: Fri Apr 25 16:11:28 2008
from: Tim Osborn <t.osborn@uea.ac.uk>
subject: Re: rd0 programs
to: Ian Harris <i.harris@uea.ac.uk>

   ok -- I'll make some new 2.5 degree normals files for pre, in Mark's binary format so they
   should be able to be "slotted in".  will let you know when they're ready.
   Cheers
   Tim
   At 15:57 25/04/2008, you wrote:

     Hi Tim,
     There are two rd0 programs. Here's an extract from my big READ_ME diary/file, from a
     year or so ago:
     20. Secondary Variables - Eeeeeek!! Yes the time has come to attack what evenTim seems
     to have been unhappy about
     (reading between the lines). To assist me I have 12 lines in the gridding ReadMe file..
     so par for the course.
     Almost immediately I hit that familiar feeling of ambiguity: the textsuggests using the
     following three IDL programs:
          frs_gts_tdm.pro
          rd0_gts_tdm.pro
          vap_gts_anom.pro
     So.. when I look in the code/idl/pro/ folder, what do I find? Well:
      3447 Jan 22  2004 fromdpe1a/code/idl/pro/frs_gts_anom.pro
      2774 Jun 12  2002 fromdpe1a/code/idl/pro/frs_gts_tdm.pro
      2917 Jan  8  2004 fromdpe1a/code/idl/pro/rd0_gts_anom.pro
      2355 Jun 12  2002 fromdpe1a/code/idl/pro/rd0_gts_tdm.pro
      5880 Jan  8  2004 fromdpe1a/code/idl/pro/vap_gts_anom.pro
     In other words, the *anom.pro scripts are much more recent than the *tdmscripts. There
     is no way of knowing which Tim
     used to produce the current public files. The scripts differ internally but - you
     guessed it! - the descriptions at
     the start are identical. WHAT IS GOING ON? Given that the'README_GRIDDING.txt' file is
     dated 'Mar 30  2004' we will
     have to assumethat the originally-stated scripts must be used.
     I've just reviewed the rd0_gts_anom.pro file, and sure enough, it is designed to read
     precip anomalies. specifically, it contains this line in both the 61-90 and full
     sections:
      pregrd(nland)=((pregrd(nland)/100.0)+1.0)*prenorm(nland) ; make pre anom into abs
     There is nothing comparable in rd0_gts_tdm.pro.
     So.. I'll have a play with this! Bearing in mind that the precip normals are probably up
     the creek..
     Cheers
     Harry
     Ian "Harry" Harris
     Climatic Research Unit
     School of Environmental Sciences
     University of East Anglia
     Norwich NR4 7TJ
     United Kingdom
