date: Fri, 03 Oct 2008 17:15:50 +0200 from: Håkan Grudd subject: Arctik2k to: Keith Briffa Arctic2k ___________________________________________________________________________________________ Scientific goals General goals of the Working Group are to generate and synthesize high-resolution paleoclimate data to assess and elucidate both the timing and variability of the Arctic climate change during this period. Furthermore, the group will contribute to the series of regional reconstructions of the last 2000 years in the new PAGES Focus 2 "Regional Climate Dynamics". Specific scientific questions targeted by the WG include: - Is the 20th century warming of the Arctic unprecedented in the last 2000 yr? Were temperatures in Medieval time warmer than those of the last several decades, and if so, what was the spatial pattern of temperature anomalies? - What is the multi-decadal to century scale variability in Arctic climate? - What are the spatial-temporal modes of climatic variability, including the Arctic Oscillation, on time scales ranging from inter-annual to centennial? How persistent are they beyond the instrumental record? What is the rate of change? - How do the extreme mean climate states of the historical record (i.e. LIA & MWP) relate to these long-term modes of Arctic climate variability? - What are the frequencies of extreme events in the Arctic? - What are the critical thresholds in the arctic system? - Was natural climate variability in the Arctic in the past also generally amplified in comparison with mid-latitudes? - What portion of the Arctic-wide and regional temperature changes during the last 2 kyr can be explained by changes in solar irradiance and volcanic activity, and what portion is related to internal adjustments of the climate system? -- ________________________ Håkan Grudd, PhD Department of Physical Geography & Quaternary Geology Stockholm University SE-106 91 Stockholm URL: [1]http://ink.su.se Phone: +46 (0)8 674 7591 Fax: +46 (0)8 16 4818 E-mail: [2]hakan.grudd@natgeo.su.se Personal webpage: [3]http://people.su.se/~hgrud