Thursday, May 3, 2012

3781.txt

cc: dave lister <d.listeratXYZxyz.ac.uk>
date: Wed, 30 Apr 2008 15:41:51 +0100
from: Tim Osborn <t.osbornatXYZxyz.ac.uk>
subject: Re: Rain Days - Russia
to: Ian Harris <i.harris@uea.ac.uk>,Phil Jones <p.jonesatXYZxyz.ac.uk>

<x-flowed>
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?

> 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.

>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).

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.osbornatXYZxyz.ac.uk
phone: +44 1603 592089
fax: +44 1603 507784
web: http://www.cru.uea.ac.uk/~timo/
sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm


</x-flowed>

No comments:

Post a Comment