cc: Tim Osborn <t.osborn@uea.ac.uk>, k.briffa@uea.ac.uk, masson@dsm-mail.saclay.cea.fr, hutterli@climate.unibe.ch, wanner@giub.unibe.ch, juerg@giub.unibe.ch, karin@natgeo.su.se, eystein.jansen@geo.uib.no, ddj@gfy.ku.dk, sigfus@gfy.ku.dk, guiot@cerege.fr, esper@wsl.ch, frank@wsl.ch, eavaganov@forest.akadem.ru, antti.ojala@gsf.fi, r.battarbee@geog.ucl.ac.uk, j.holmes@ucl.ac.uk, brazdil@sci.muni.cz, jerome@lgge.obs.ujf-grenoble.fr, barbante@unive.it, shishov@forest.akadem.ru
date: Mon, 14 Feb 2005 16:46:25 +0100
from: Hubertus Fischer <hufischer@awi-bremerhaven.de>
subject: Re: IMPRINT task 1.1 coming together
to: petit <petit@lgge.obs.ujf-grenoble.fr>

Hi everybody,

Not knowing whether this discussion is still acute I strongly support Jean-Robert's arguments. While the concentration of dust is coupled to source and transport variations, the dust size is essentially only to the latter and promises unrivaled information on long-range transport conditions.
This parameter should be extensively used in the coming years as outlined in Barbara Delmonte's and Urs Ruth's work.

Cheers Hubertus


----- Original Message -----
From: petit <petit@lgge.obs.ujf-grenoble.fr>
Date: Monday, February 14, 2005 2:47 pm
Subject: Re: IMPRINT task 1.1 coming together

> Dear Tim,
> 
> In response to your comment nb 2 and 8 from document Task  1 
> section B4 and 
> B8 to remove the dust studies from task 1.1 to reduce budget, I 
> would like 
> advocate for having dust project studies as part of IMPRINT.
> 
> Recent works on dust studies from Antarctic ice cores have changed 
> our view 
> on the climate variability over the east Antarctic plateau, but 
> unfortunately yet not widely known.
> Variability in dust size parameters during Holocene(signal/noise 
> ratio) is 
> indeed well higher and significant than other climate proxies 
> (e.g. stable 
> isotope, ...). Moreover the dust size differs from the total dust 
> concentration and is almost only dependant  on the atmospheric 
> circulation 
> modes (Delmonte et al., 2002, 2004, and in press ).
> During the last deglaciation and the Holocene period, it was shown 
> the size 
> distribution changes have been associated to the (pseudo 
> oscillating) 
> shifts of the polar vortex over East Antarctica between Dome 
> region and 
> Vostok region (Delmonte et al., 2004, and in press ).  Moreover, 
> during 
> Holocene (up to 3000 BP ) significant secular to sub millennial 
> and secular 
> periodicities are present in the dust records with a dominant 200 
> year 
> (solar?) period which is common to all records (Delmonte et al, in 
> press, 
> attached).
> 
> Note also that such spectrum of climate sub millennial and secular 
> variability  in Antarctica (prior 3000 BP) seems consistent with 
> NH  variability of the last 2000 years as recently presented by 
> Mobek et 
> al, Nature, feb 10, 2005, .
> GCM have been indeed used to assess the observed recent climatic 
> change 
> over Antarctica (warming Peninsula and cooling East Antarctica and 
> the 
> shift in the polar vortex) and associated due to the recent ozone 
> depletion 
> (e.g. papers from Solomon and Thompson ? in Science).
> 
> The proposed task aims to document the 0-2000 BP period in 
> Antarctica from 
> existing ice cores and pits, with the ambition to compare with the 
> natural 
> forcings from solar variability (10Be) and volcanic input.Our task 
> is also 
> to generate  dust data from pits and shallow  cores covering  the 
> instrumental period.
> 
> Dust size studies are currently developed at Laboratory of 
> Glaciology 
> (LGGE) with collaboration with University Bicocca, Milano for 
> coulter 
> counter measurements and also  University of Berne  and AWI  
> Bremerhaven 
> are using laser system for flow-line analysis
> 
> I strongly advocate for having this project part of IMPRINT which 
> appear 
> relevant to tasks1.1 task 1.2, and task 1.5.
> Without this support our European community will not be able to 
> continue 
> this original and promising research.
> 
> Sincerely yours
> 
> Jean Robert Petit
> 
> 
> 
> --------------------------------------------------
>         Jean Robert PETIT
> 
>        LGGE-CNRS BP 96
> F-38402 St Martin d'Heres Cedex
>       Tel:  +33 (0)4 76 82 42 44
>        Fax: +33 (0)4 76 82 42 01
> 
> petit@lgge.obs.ujf-grenoble.fr
> 
> http://www-lgge.obs.ujf-grenoble.fr
> --------------------------------------------------
>