cc: k.briffa@uea.ac.uk, domraynaud@glaciog.ujf-grenoble.fr date: Fri, 14 Apr 2000 13:53:24 -0400 from: "Raymond S. Bradley" subject: Re: HIHOL letter to: Jonathan Overpeck 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: <http://www.geo.umass.edu/cli mate/climate.html Paleoclimatology Book Web Site (1999): http://www.geo.umass.edu/climat e/paleo/html