Late Holocene Climate Variability
Spring 2009, 3 ECTS
Updated: 16 Mar 2009
1. Title
Late Holocene climate variability (3 ECTS)
2. Short description
The course will be based on chapter 6 in the latest IPCC report (2007), focusing on the last two thousand years. Each day of the course will have a special theme, e.g. paleoclimate modeling. A lecture is given during the morning (which will be open to other than the PhD students). In the afternoon there will be discussion seminars based on Ch.6 in IPCC and papers that the lecturer have selected for the students to read beforehand.
The following topics will be covered:
- Paleoclimate - an Introduction
- Historical records
- Tree-rings
- Paleoclimate modeling
- Ice core records
The course is free of charge.
3. Location and dates
The course will be located at department of Earth Sciences, University of Gothenburg. The course starts at March 16th and ends on March 20th.
4. Aim of the course
The course will focus on interpretations of climate variability in the last few millennia from climate proxy data. Some of the leading scientists in paleoclimatology from Europe will provide insight to a range of climate indicators, climate proxies, which have provided much of the information we have about past climates. The benefits and limitations of climate indicators (such as tree rings and ice cores), as well as climate models, will be explored. In light of this, the reliability of recent reconstructions of global temperatures will be assessed.
5. Target group and entry requirements
The target group for the course is PhD students with interest in paleoclimatology. Entry requirements are basic knowledge of climatology. Students are recommended to read
chapter 6 in the latest IPCC report before the course starts. For each 'theme' the students will have a selection of articles to read before the seminars, these will be available on the course homepage.
6. Course organizers
The Regional Climate Group (RCG), Department of Earth Sciences, Gothenburg University; Associate Professor Hans Linderholm (hansl@gvc.gu.se)
7. Teaching staff
Professor Gerrit Lohman, Alfred Wegener Institute for Polar and Marine Research; Professor Juerg Luterbacher, University of Bern; Dr David Frank, Swiss Federal Institute for Forest, Snow and Landscape; Dr Eduardo Zorita, GKSS Research Center; Dr Bo Vinther, Centre for Ice and Climate.
8. Course programme & Literature
16/3:
Gerrit Lohmann ( Alfred Wegener Institute for Polar and Marine Research ) : General Introduction into Paleoclimate dynamics.
Abstract: In attempting to account for long-term paleoclimatic variations, we are led to broaden our view of the climate system and to restructure our approach to a fuller theory of climate. We begin by describing the external forcing of the climate system and the observed response, as represented by proxy evidence for paleoclimatic variations. One focus of the course is to identify driving mechanisms for climate change. This is done through numerical models of the Earth system and statistical analysis of instrumental and proxy data. Special areas: feedback mechanisms in the climate system; the role of the global oceanic thermohaline circulation for paleo and recent climate variations; deglaciation; Holocene climate; Glacial climate; Climate modes like ENSO and NAO; Milankovitch theory of the ice ages.
CV: Gerrit Lohmann studied physics and mathematics at the Universities Göttingen and Marburg, and received the diploma in physics in 1992. From 1992 to 1995 he worked as a graduate research assistant at the Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven, Germany. In 1994, he was a visiting scientist at the Earth Science Centre, University of Gothenburg and got a scholarship of the German Academic Exchange Service DAAD. He obtained his Ph.D. Degree in physics in Bremen in 1995. After about 5 years at the Max-Planck-Institute in Hamburg working on climate modelling, he worked at the Geosciences Department of Bremen and the Meteorological Institute at the University of Hamburg. From 2002 to 2004, he had a tenure position at Bremen University, Center for Marine Environmental Sciences and was lecturer at the University of Hamburg and the European Graduate College in Marine Sciences. He authors more than 50 peer-reviewed publications in international journals in the fields of climate modelling, and statistical analysis of observational and proxy data. Since July 2004, he is a professor for "Paleoclimate Dynamics" at the Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven in cooperation with the Physics Department at the University of Bremen. Gerrit Lohmann is the President of the climate division of the European Geoscieneces Union (2006-2009). Since 2008, Gerrit Lohmann is the initiator and speaker of the Earth System Science Research School (ESSReS) at the University of Bremen, Jacobs University Bremen, and AWI Bremerhaven. He is head of the COSMOS Paleo activities and is the speaker of the DFG Research Unit "Understanding Cenozoic climate cooling".
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18/3:
David Frank (Palaeoclimatology Group, Swiss Federal Research Institute WSL) : Climate reconstructions from Tree-rings.
Abstract: Tree-ring data are one of the most important archives used to reconstruct annual variations in climate over the past millennium (IPCC 2007). For the land areas of the mid to high latitudes, tree-ring data are widespread and may provide information on temperature, precipitation, or drought variation depending upon both site ecology and the measured tree-ring parameter. Despite their importance, most hemispheric scale temperature reconstructions do not include tree-ring material from more than 6 locations at AD 1000, making any such archives exceptionally valuable towards understanding past regional to hemispheric-scale climate variation. In this talk, recent progress towards developing millennial-length records of climatic variation from tree-ring archives, with a focus on the European region, will be discussed. A basic introduction to dendrochronology will first be provided with topics including crossdating and age-trend removal/ preserving long-term climatic trends. I will show examples of regional drought and temperature reconstructions, and then how compilations of these regional records allow large-scale climatic change to be understood and the strength of external forcing and feedbacks to be quantified. The talk will conclude with selected examples of on-going research activities and further challenges and opportunities in using tree-ring data to understand climate variation.
CV: David Frank is a currently the Palaeoclimatology Group Leader within the Dendro Science Unit at the Swiss Federal Research Institute WSL. His research interests include using tree-ring data as a tool to reconstruct past climate, understanding how climate affects intra-seasonal to centennial-scale tree growth, and methods of climate reconstruction.
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19/3:
Eduardo Zorita (GKSS Research Centre, Geesthacht ) : Applications of climate models for paleoclimate research.
Abstract: Climate models represent an important tool for the understanding of past, present and future climates. The 'category' of climate models comprises different types.(energy balance models, models of intermediate complexity and full-blown general circulation models) and each type of model is more adequate than others to investigate particular questions in paleoclimate. Furthermore, a knowledge of their strengths and limitations is certainly required to interpret their output, in particular when this output with jointly analysed with proxy records.
Past and future climate change is mainly caused by changes in the 'external' forcing, so that paleoclimate simulations also require and understanding of past external forcings. This concept, however, also depends on the climate model - for instance for some models CO2 concentrations are an external forcing, whereas for others they are an internal model variable. Also, the implementation of the external forcings into the model set-up may be dependent on the nature of the model.
Paleoclimate research based on the analysis of proxy date often hinges on underlying assumptions that cannot be easily validated, for instance. An example may be stationarity of relationships between climate variables in the past through time. Another example is that proxy records are interpreted as records of physical variables often neglecting other sources of proxy variability. Some of these assumptions can be tested in the virtually reality (Second Lifes) provided by the output of climate simulations. These tests sometimes lead to surprising results that may put into question some of the most basic assumptions used to interpret proxy records.
CV: Eduardo Zorita holds his PhD in solid state physics from the University of Zaragoza (Spain). After his graduation he moved to the Max-Planck-Institute of Meteorology in Hamburg, where he worked for some years in designing statistical methods for the estimation of regional climate change. After a few years as a post-doc at the Institute of Dynamical Oceanography and Climatology in Paris, he moved to the GKSS Research Centre in Geesthacht. His interest mainly lie in the application of statistical and modelling methods for the reconstruction and analysis of the climate of the past millennia.
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20/3:
Bo Vinther (Centre for Ice and Climate, University of Copenhagen) : Detailed Holocene ice core records from Greenland - resolving variations on time scales from seasons to millennia.
Abstract: Twenty ice cores drilled in medium to high accumulation areas of the Greenland ice sheet have been used to extract seasonally resolved stable isotope record. An investigation of the records shows that they can be related to Greenland and Icelandic temperatures as well as atmospheric flow for the past 150-200 years. Ice cores from six locations in Greenland/Canada cover the entire Holocene warm period (the past 11700 years). During the past 5 years all these ice cores have been cross-dated using volcanic reference horizons detectable in ice core conductivity measurements. Now these cross-dated records can be used to give information both on past Greenland climatic conditions and the evolution of the Greenland ice sheet in response to the abrupt warming that happened at the end of the last glacial period 11700 years ago.
CV: Bo Vinther is a PostDoc at the Centre for Ice and Climate, University of Copenhagen. Bo is working with the interpretation of seasonally resolved ice core data from Greenland ice cores, especially on how to retrieve the best possible records of past Greenland temperatures. This work is being carried out in collaboration with professors Phil Jones and Keith Briffa at the Climatic Research Unit (CRU), where Bo did a one year PostDoc. Bo is also heavily involved in the creation of a common time scale for all Greenland ice cores. A goal that has almost been accomplished and has taken years of work doing careful annual layer counting and cross-dating. At present Bo is involved in estimating past changes in Greenland ice sheet elevation, and during summers he is participating in the ongoing NEEM deep ice core project being carried out in NW Greenland.
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9. Registration
To apply, send an email to Hans Linderholm at hansl@gvc.gu.se with name and affiliation and short description of PhD project. Dead-line for registration March 13th 2009.