www'clivar'orgorganizationpagespages'php

1
Overall goal To improve the understanding of
decadal to centennial climate variability
Co-chairs Gavin Schmidt, Eystein Jansen Contact
CLIVAR Anna Pirani Contact PAGES Thorsten Kiefer
www.clivar.org/organization/pages/pages.php
2
PAGES / CLIVAR in the distant past

• History
• - Developed in the early 90s
• - to improve understanding of decadal to century
  scale climate variability
• - high-resolution paleoclimatic data to improve
  the predictability of change (corals, tree-rings,
  varved sediments and ice cores, ...)
• Topics
• dynamics of low-latitude climate change
• global ocean thermohaline variability
• regional-to-global scale hydrologic variability
• dynamics of abrupt climatic change
• model evaluation and improvement
• climate change detection
• ESF conference series, research initiatives
  (ARTS, PMIP)

3
PAGES / CLIVAR - in the distant past

• MEETINGS
• Venice meeting 1999 Linking modeling-data
  community
• Il Ciocco, Italy, 2001 Abrupt Climate Change
• Hadley Cell workshop 2002 Merging of P/C
  scientists
• Drought workshop, US 2003 International
  networking
• ESF, Spain, 2003 Linking modeling-data community
• PMIP Meetings

4
PAGES former structure
Activities centered around five programmatic
foci

• PANASH - The PEPs
• CLIVAR / PAGES Intersection
• IMAGES
• Polar Programs
• Past Ecosystem Processes and Human-Environment
  Interactions

5
PAGES new scientific Foci
4 Thematic Foci 4 Cross-cutting themes
P/C intersection does not have the role of a
scientific focus any more, but of a group to
conduct activities that work towards focus goals.
6
PAGES/CLIVAR present phase

• Reconstitution and revision
• C/P-intersection working group meeting
  Victoria, Canada, November 2004

Developed new vision to reflect on specific
issues, based on paleo-reconstruction,
instrumental data analysis, and modeling.
Co-chairs Andrew Weaver (now Gavin
Schmidt) Eystein Jansen
7
PAGES / CLIVAR present phase

• Key scientific issues
• Climate variability over the last few millennia
• Abrupt climate change - extreme events
• Hydrologic, biospheric, land-surface interactions
• Tropical-extratropical links including ocean and
  atmospheric teleconnections
• Overarching and Cross-cutting Implementation
  issues
• Outreach - workshops - link model/data
  communities

8
Overarching and Cross-cutting Implementation
Joint Publication Exchanges - PAGES News in
2005 Climate Forcings
9

Climate Variability - Past Millennia
Funded by EPRI (Electric Power Research
Institute), PAGES and CLIVAR
10
Climate Variability - Past Millennia
Assessment and improvement of models ...
Jones and Mann, 2004
11

Climate Variability - Past Millennia
Europe and Northern Hemisphere 500-year
temperature variability
... and reconstructions.
Luterbacher et al. 2004
12
Europe Winter (D,J,F) EOF1-3 1766-2000
13

Climate Variability - Past Millennia
Sub-themes -Forcing and modeling -Methods of
multiproxy reconstructions -Model/data
comparison -Spatial patterns of past climate
change

• Resulted in follow-up ideas for
• - Synthesis paper
• Proxy data uncertainty workshop
• - Paleoclimate Reconstruction Challenge

14
Climate Variability -- regional studies 2000 years
15
Workshop in Argentina in October 2006 radically
increased knowledge of high resolution
paleoclimate records in South America for
synthesis
Workshop papers to be published in Paleo3
16
MedCLIVAR
MedCLIVAR - Past Climate in the Eastern
Mediterranean and the Middle East November 2006,
Spain (PAGES co-sponsored)
Luterbacher et al. 2006
17
Abrupt Climate Change The 8.2 ky event
Grootes et al. 1993
PAGES/CLIVAR workshop Rapid Climate Changes and
the 8.2 ka Event October 2006, Birmingham, UK
Clarke et al. 2003
18
Abrupt Climate Change The 8.2 ky event
Temperature C
Precipitation mm/day
Modeled response to meltwater influx into the
N. Atlantic Simulation of 8.2 ky meltwater
event Incl. forward modeling of proxies.
?18O precip
?18O seawater
LeGrande et al., 2006, PNAS
19
Whats to come ...?
20
Paleoclimate Reconstruction (PR)
Challenge Workshop 9-11 June 2008 Trieste,
Italy (Kim Cobb, Sandy Tudhope, Jonathan
Overpeck, Janice Lough)
Defining, reducing and representing uncertainties
in high-resolution proxy climate data used for
reconstructions of climate over the past few
millennia 1. Identify main sources of
uncertainty in proxy data. 2. How to better
represent proxy uncertainties to non-specialists
and modelers. 3. Develop strategies for reducing
proxy data uncertainties. 4. Internationally
coordinated strategy for (re-)sampling key
sites. 5. Make recommendations for data sharing
via data centers.
Funding ICTP Trieste, EPRI, PAGES ... US NSF ?,
CLIVAR ??
21
Paleoclimate Reconstruction (PR) Challenge
1. MODEL GROUP Coord. Caspar Ammann AOGCM output
as a surrogate for real world-like climate
information. 2. PSEUDO-PROXY GROUP Coord. Nick
Graham From the climate model output, generate
synthetic, but realistic, climate proxy
(pseudo-proxy) information. 3. RECONSTRUCTION
GROUP Coord. DArrigo open to
community Pseudo-proyx information will then be
used to generate climate reconstructions Because
the true model climate is known, the
methodologies utilized by the different groups
can be tested in their skills to reconstruct the
underlying climate from the pseudo-proxy
information.
22
Focus 3 Working Group - Global Monsoon
Global Monsoon Precipitation Domain

• Definition based on summer-winter contrast and
  concentration of rain in summer
• Annual range greater than 150 mm (JJA minus DJF
  in NH)
• Local summer (JJA in NH) exceeds 35 of the
  annual rainfall

Wang and Ding 2006 GRL
23
7 major monsoons systems of the world
EAM
NAMS
IM
NAfM
AUM
SAMS
SAfM?
NDVI image for 21-31 August 2000, from Pathfinder
AVHRR
NDVI surface vegetation
24
A global perspective is imperative for
understanding fundamental monsoon dynamics.
Why Global Monsoon?

• The physical principle of conservation of mass,
  moisture, and energy applies to the global
  atmosphere and its exchange of energy with the
  underlying surfaces (Trenberth et al., 2000).
• All seven regional monsoons are driven by the
  annual cycle of the solar radiative heating and
  coordinated and connected by the global divergent
  circulation necessitated by mass conservation.
• Regional monsoon systems interact with each other
  and with global oceans

25
Regional monsoon systems interact with each other
and with global oceans

• A strong South Asian summer monsoon tends to be
  followed by a strong Australian and weak eastern
  African monsoon (Meehl 1997).
• Indian monsoon-East Asian monsoon (Kripalani
  1997)
• South American monsoon and the African monsoon
  are possibly related (Biasutti et al. 2003).
• Teleconnection exists between East Asian-western
  North Pacific summer monsoon and North American
  summer rainfall (Wang et al. 2001 Lau and Weng
  2002).
• Continental monsoons are interactive with
  surrounding oceans. Sahel drying is a response to
  warming of the South Atlantic relative to North
  Atlantic SST Southern African drying is a
  response to Indian Ocean warming (Hoerling et al.
  2006).

26
Remarks

• The 30-year averaged global monsoon Precipitation
  index in the forced run reveals significant
  centennial-millennium variability. (200 years)
• The change in the global monsoon precipitation
  tends to be in tendon with the global mean
  temperature change.
• Weak global monsoons are observed during the
  Little Ice Age (1450-1850), during which three
  weakest global monsoon period occur around 1680,
  1460, and 1800, which fall in, respectively, the
  maunder Minimum (1645-1715), Sporer minimum
  (1450-1550), and Dalton minimum (1790-1820)
  periods.
• Strong global monsoon precipitation is seen in
  the Medieval Warming Period (1050-1250) with
  three distinguished peak around 1210, 1150 and
  1060, respectively.

27
Monsoon variations recorded in Stalagmites,
Done-Ge Cave

Y.Wang et al., 2005, Science
28
Global Monsoon Issues and science questions

• What causes regional differences in the present
  day climate, in the past, and in a global warming
  environment?
• How do we best measure the strength of the global
  monsoon preci? How well do the coupled climate
  models simulate the observed climatology and long
  term trends of the global monsoon precipitation?
• What are the major characteristics describing the
  spatial distribution of observed trends in global
  monsoon precipitation?
• How do the changes in global monsoon relate to
  external forcing, anthropogenic forcing and
  global temperature change?
• Have significant changes of global land monsoon
  rainfall been detected that are likely to be
  deducible from the atmospheres response to the
  observed SST variations?
• How do the structures of GM precipitation
  anomalies differ between the MWP and LIA epochs,
  as well as between MWP and the present climate?
  How to explain the differences?

29
Global monsoon Implementation

• Townhall Meeting and planning discussions at
  theThird Alexander von Humboldt Symposium on
  Asian Summer Monsoon in Beijing, August 28, 2007
• Cooperation with modern climatological programs,
  such as the joint CLIVAR-GEWEX Asian Monsoon
  Experiment (GAME), CLIVAR VAMOS Variability of
  the American Monsoon Systems, African Monsoon
  Multidisciplinary Analysis (AMMA), Monsoon Asia
  Integrated Regional Study (MAIRS)
• Setting up a long-term PAGES programme to include
  present and past data-producers and analysts and
  modelers and to cover all the monsoon systems
• Organizing a first Global Monsoon Symposium in
  2008 followed by special issue in a peer-reviewed
  journal

30

• David M. Anderson
• Jose Marengo
• R. Ramesh
• Caroline Davies
• Paul A. Baker
• Abdoulaye SARR
• Philip A. Meyers
• Rajeev Saraswat
• Ashish Sinha
• Ryuji Tada
• Rong Fu
• Shijie Li

• Dirk C. Leuschner
• K. SELVARAJ
• A.K.Bhattacharyya
• Bing Wang
• Sheri Fritz
• Kerry Cook
• Dominik Fleitmann
• Pinxian Wang
• Zhongli Ding
• Peter Kershaw
• Pascale Braconnot

31
Questions?

• Proxies How well are paleomonsoon data
  comparable, given the differences in used proxies
  and the changes in space and time?
• Can we distinguish the global and regional
  signals of the paleo-monsoon?
• How should the paleo-monsoon be studied in
  connection with other climate systems?
• How should be the Working Group organized ?

32
PAGES/CLIVAR Intersection Upcoming activities and
opportunities

• 9-11 June 2008, Trieste Italy Proxy Data
  Uncertainties
• Paleoclimate Reconstruction (PR) Challenge
• Global Monsoon Working Group, 1st workshop 2008
  in Shanghai
• Regional climate variability during the last
  2000 years
• June 2009, PAGES Open Science Meeting, USA P/C
  component?
• Another joint newsletter in 2009?