Tuesday, May 15, 2012


cc: k.briffa@uea.ac.uk, domraynaudatXYZxyzciog.ujf-grenoble.fr
date: Fri, 14 Apr 2000 13:53:24 -0400
from: "Raymond S. Bradley" <rbradleyatXYZxyz.umass.edu>
subject: Re: HIHOL letter
to: Jonathan Overpeck <jtoatXYZxyzrizona.edu>

I forgot to send this revised draft letter...

Dear ,

I am pleased to invite you to a special PAGES/NSF sponsored meeting being
held in October this year. Its purpose is to redefine what we know about
"High-Resolution Climate Variability of the Holocene" and we refer to the
project as HIHOL.
The meeting will be very much an informal gathering of different
palaeoclimate specialists: including those working on ice, marine,
lacustrine, and other terrestrial records, plus specialists in records of
potential climate forcing and ecosystem and climate modellers. Attendance
is limited to 50 participants and will be by invitation only. The final
product will be a state-of-the-art review of Holocene Climate Variability,
to be published as a Special Issue of the journal The Holocene, already
scheduled for publication in 2001. The authors of papers to the Holocene
will be determined later, but if you are asked to write or contribute to a
team-authored paper, please be aware that the deadline for submitting text
will be December 31, 2000. Attendance at the meeting is an implicit
agreement to meet this deadline!!

At this point, we have not finalised the exact timetable of the meeting
though the date is now fixed (see below). We envisage a series of initial
review type syntheses of information in different disciplines, with
accompanying cross disciplinary discussions and wider syntheses leading to
a series of final papers.

We will adopt the 'basic overarching questions', model and structure the
meeting around attempting to answer these in the framework of several
sessions - starting with

Stream 1 : Introduction to general concept, aims, overarching questions
Established view of the Holocene variability - provocation
Forcing / and 'Global Signals'
Insolation, Geographical/seasonal, spatial - quantitative
Greenhouse gases
Volcanic aerosols
Berylium (and ice volume)
Aerosols and vegetation
Thermohaline circulation

Stream 2 : Low Latitudes: Tropical Warm Pool, Hadley cell, ENSO, Monsoons

Stream 3 : Sub tropical regions, zones of the westerlies - NORTH and SOUTH

Stream 4 : Polar regions, high latitudes - NORTH and SOUTH

Stream 5 : Model-based Research, range of complexity, mix of
time-slice and longer runs

The overarching questions we envisage are:

What is the 'best resolved' picture of Holocene climate variability that
can be synthesised in the different regions: we wish to produce the optimum
indications that explicitly reveal millennium; century and annual to
decadal variability.

� Are changes at these various timescales statistically-significant
annual-to-decadal variability linked and are they in-phase or out-of-phase?
� Are there major synchronous abrupt events and what are their
relevant magnitudes - e.g. at 8.2K calendar years ago; at 4K years ago; at
2K years ago; at 540A.D. etc.
� How has the carbon cycle changed and what were the relative roles
of the ocean and terrestrial biosphere?
� What is the evidence for changing thermohaline circulation and do
the data support the theory of antiphase temperature anomalies in the north
Atlantic and southern oceans?
� What is the role of changing ice volume/sea level?
� What is the role of changing seasonal insolation on climate
changes, e.g. low latitude effects on monsoon variability?

Not all disciplines will contribute to all streams - talks will be
allocated to 'most appropriate' slots. The precise balance of presentations
and discussion has not yet been finalised but we might ask you to do one
of a range of things that include presenting an up to date review (
including the work of other colleagues ) to contributing to the
discussion/synthesis and authoring/coauthoring one of the final
papers. At this pojnt, we just need to know from you if you can attend and
contributing at some level to this project.

The meeting will take place over three days - the Tuesday, Wednesday,
Thursday, 24, 25, 26th October 2000 - in the Hotel ARAXE in
Isle-sur-la-Sorgue, close to Avignon, France. We would expect people to
arrive on the Monday and leave on the Friday. The hotel is an excellent
base for a longer stay and several of the participants may wish to stay
over for a weekend either end of the meeting.

Raymond S. Bradley
Professor and Head of Department
Department of Geosciences
University of Massachusetts
Amherst, MA 01003-5820
Tel: 413-545-2120
Fax: 413-545-1200
Climate System Research Center: 413-545-0659
Climate System Research Center Web Site:
Paleoclimatology Book Web Site (1999):

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