cc: dave lister <d.lister@uea.ac.uk>
date: Wed Apr 30 17:31:26 2008
from: Phil Jones <p.jones@uea.ac.uk>
subject: Re: Rain Days - Russia
to: Ian Harris <i.harris@uea.ac.uk>, Tim Osborn <t.osborn@uea.ac.uk>

    Harry, Tim,
      What this looks like is a different threshold for the rainday data for the period
    before 1984 from that after 1989. As all these stations start in 1936, the data come
    from daily precip data, so someone (could have been Mark) has calculated the
    rainday counts directly. I suspect this was for 0.1mm.
       From CLIMAT/MCDW the threshold is likely 1.0mm so this is why the day counts
    have reduced.  As this has likely happened at all the 250+ stations across the fUSSR
    that are in the daily dataset we used to have, I'd suggest doing (1), but need to extend
   it
    a little.
       Don't do just Russia, but all fUSSR. You can get this by doing all WMO IDs beginning in
   2
    or 3.  The fUSSR has all countries have all WMO Ids from 20-39.
      The issue will occur in other fUSSR countries, but is less important further south, as
    there it rains less, but when it does it generally more than 1.0mm, so
    the value of the threshold doesn't matter that much.
    Cheers
    Phil
   At 15:52 30/04/2008, Ian Harris wrote:

     On 30 Apr 2008, at 15:41, Tim Osborn wrote:

     At 14:27 30/04/2008, Ian Harris wrote:

     2388400  6160   9000   63 BOR                  RUSSIA (ASIA) 1936
     2007    -999    -999
     2926300  5845   9215   78 JENISEJSK            RUSSIA (ASIA) 1936
     2007    -999    -999
     2928200  5842   9740  134 BOGUCANY             RUSSIA (ASIA) 1936
     2007    -999    -999
     Their datasets are attached.

     Not attached?

     Durrrrrrr. Attached.

      Looks like the data added 1990 and after
     is significantly lower than the previous data (on which the normals
     would be based).
     This is the geneaology of the current rd0 database:
     wet.0311061611.dtb
             +
     rdy.0709111032.dtb  (MCDW composite)
             +
     rdy.0710151817.dtb  (CLIMAT composite with metadata added)
             V
             V
     wet.0710161148.dtb
     However, as I've now understood that this problem existed in 2.1,
     it's back to square one. we have two courses of action, I think.
     Incidentally, Tim - I've checked and I must have imagined a big MCDW
     archive - both CLIMAT and MCDW bulletins were only acquired from Jan
     2003.

     presumably on the basis that Tim M. had already incorporated them
     for the period prior to 2003?  Mitchell & Jones (2005), Table 1,
     indicates that he did indeed do that for 1990-2002 for MCDW and for
     1994-2002 for CLIMAT.  Their Figure 1, though rather blurred,
     suggests that it is MCWD not CLIMAT that dominates for wetdays.

     well the series look to diverge from 1990 rather than 1994, so that
     figures.

     1. We could delete all rd0 data after 1990 and rely on synthetics.
     This may introduce noticeable incongruities in certain areas,
     especially as we're changing methodology just after the normals
     period.
     2. We could just derive rd0 from the precip data. After all, it's a
     pretty good relationship.
     How about I do both, and we compare? It won't take too long..

     I would suggest doing (1) first; then do (2) if incongruities are
     evident in (1).
     However, the drop in Russia occurs in 1990.  By eye, I thought it
     was 1991, but by inspecting the data, it is clear that they have
     dropped by summer 1990 and perhaps part-way through spring 1990.
     Therefore can you drop all rd0 from the start of 1990 onwards,
     rather than after 1990 (which could mean 1991 onwards).

     I started like that, then realised we'd lose stations that needed
     that extra year to qualify!
     However, see the attachment - the new data kicks in in May 1990 so
     you are right. I'll back track again and re-do with a Dec 1989 cutoff.
     Cheers
     Harry

     Phil, what do you think?
     Cheers
     Tim
     Dr Timothy J Osborn, Academic Fellow
     Climatic Research Unit
     School of Environmental Sciences
     University of East Anglia
     Norwich  NR4 7TJ, UK
     e-mail:   t.osborn@uea.ac.uk
     phone:    +44 1603 592089
     fax:      +44 1603 507784
     web:      [1]http://www.cru.uea.ac.uk/~timo/
     sunclock: [2]http://www.cru.uea.ac.uk/~timo/sunclock.htm

   Prof. Phil Jones
   Climatic Research Unit        Telephone +44 (0) 1603 592090
   School of Environmental Sciences    Fax +44 (0) 1603 507784
   University of East Anglia
   Norwich                          Email    p.jones@uea.ac.uk
   NR4 7TJ
   UK
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