Comparing data and model estimates
of hydroclimate variability and change over the Common Era
June 1-3, 2016


Hydroclimate is an increasing focus of the paleoclimate community and the last several years have seen important data products developed to study hydroclimate variability and change during the Common Era. A growing collection of proxy records have been selected and discussed by the PAGES 2K regional working groups and hydroclimate is targeted as the next key variable of study.

At the same time, an explosion in the number of last-millennium simulations using fully-coupled climate models has occurred over the last several years. In particular, the PMIP3 effort included a last-millennium protocol and multiple modeling centers performed the experiment, using the same configurations and resolutions adopted for the historical and future projection simulations in CMIP5. More recently, ensembles of last-millennium simulations have been performed that include single forcing experiments. All of these developments make the time ripe for exploring how climate models simulate hydroclimate change and variability and whether they do so in ways that are consistent with the paleoclimate record. Ultimately, comparisons between proxy records and model simulations will further enhance our abilities to evaluate climate models, understand the dynamics of hydroclimate variability and change, and constrain our characterizations of climate risks in the future.

Addressing these emerging themes was the focus of the workshop titled "Comparing data and model estimates of hydroclimate variability and change over the Common Era." The meeting was a joint effort of PAGES 2K the PAST2K working group of PMIP (Paleoclimate Modelling Intercomparison Project). It was held on June 1-3, 2016 at the Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA. Additional information can be found at the PAGES Calendar site and a workshop report was published in the PAGES Newsletter (copies of the full newsletter are available here and a pdf of only the workshop report is available here).

The aims of the workshop were to:

1) promote discussion and collaboration across the PAGES2k and PMIP3 communities,
2) review Common-Era proxy archives appropriate for hydroclimate assessment,
3) review the current ensemble of coupled model simulations of the Common Era,
4) review and refine best practices for model-data comparisons of hydroclimate over the Common Era,
5) advance understanding of model assessments and constraints on future projections using model-data comparisons of hydroclimate over the Common Era,
6) define future goals, products and timelines for collaborations between the PAGES2k and PMIP3 communities, specifically with regard to hydroclimate.


The agenda of the meeting was divided into four main themes:

1) Hydroclimate Proxies and Large-Scale Syntheses
2) Model Simulations of the Common Era
3) Data-Model Comparisons
4) Proxy System Modeling, Data Assimilation and Proxy Comparisons

A pdf copy of the complete agenda is available here. Copies of most presentations from the workshop and a description of the outreach event organized in conjunction with the workshop are also described in the sections that follow.


Workshop Introduction | Jason Smerdon, Juerg Luterbacher, and Steven Phipps | PDF

Hydroclimate over the Common Era from Sr/Ca and Oxygen Isotope Records of Corals | Thomas Felis | PDF

Hydroclimate Signals in Tree-Ring Chronologies Across Time and Space | Kevin Anchukaitis | PDF

Interpreting Past Hydroclimate Variability from Sedimentary Records: Challenges and Considerations | Jessica Tierney | PDF

Australasian Monsoon Variability During the Common Era Inferred from Indo-Pacific Speleothem Records | Michael Griffiths | PDF

Iso2k: A Community-Sourced Global Database of Paleo-Water Isotopes from the Past Two Millennia | Bronwen Konecky and Jud Partin | PDF

An Update on the Arctic 2k Hydroclimate Efforts | Hans Linderholm | PDF

The Role of Tree Ring Drought Atlases in Climate Change Research: State of the Art and Future Developments | Edward Cook | PDF

Warm-Season Precipitation Reconstruction over Asia in the Past Half Millennium: Tibetan Plateau | Huan Zhang | PDF

Last Millennium Simulations at GISS Including Water Isotopes | Gavin Schmidt and Allegra LeGrande | PDF

Simulations of the Common Era in PMIP4/CMIP6: Overview and Specific Issues for Studies of Hydroclimate | Johann Jungclaus | PDF

The Global Monsoon Response to Volcanic Eruptions in the CMIP5 past 1000 Simulations and Model Simulations of FGOALS | Wenmin Man | PDF

An Ensemble of Simulations for the Last Millennium with CESM | Bette Otto-Bliesner | PDF

Hydroclimate Responses to Volcanic Eruptions in CESM | Samantha Stevenson | PDF

What We Talk About When We Talk About Hydroclimate: Challenges in Model/Data Comparisons | Ben Cook | PDF

Droughts in the Last Two Millennia: Challenges in its Definition and Connection to Modes of Variability | Christoph Raible and Flavio Lehner | PDF

Challenges and Opportunities for Data-Model Comparisons in Australia | Ailie Gallant | PDF

Paleoclimate Model-Data Comparisons of Hydroclimate over North America | Sloan Coats | PDF

Hydroclimate Changes in the Tropical Pacific over the Last Millennium: Data-Model Comparisons and Possible Mechanisms | Alyssa Atwood | PDF

A Robust Null Hypothesis for the Role of the Tropical Pacific in Driving Megadrought in Western North America | Toby Ault | PDF

Introduction to Proxy System Modeling | Mike Evans PDF

Model-Data Comparisons: Understanding Water Isotopes in Speleothems | Sophie Lewis | PDF

An Update on Proxy System Modeling and Model-Data Comparison: Progress, Challenges, and Applications | Sylvia Dee | PDF

Assimilation of PAGES2k Continental Temperature Reconstructions using GCM Ensemble Member Selection | Martin Widmann | PDF

Hydroclimate Reconstructions Using Data Assimilation | Nathan Steiger | PDF

Educational Outreach Event

After the completion of the scientific workshop, two dozen middle and high school educators attended an outreach event designed to present the major themes of workshop focus and to give the teachers an opportunity to interact with scientists in an informal and interactive setting. The event started with presentations by workshop attendees Gavin Schmidt and Kim Cobb discussing their two different approaches to studying Earth’s climate history, one through the use of computer modeling of the climate system and the other through the use of paleoclimatic records. A question and answer session followed the two presentations, afterwhich the teachers were given a chance to divide into small groups and pursue discussions with additional scientists from the workshop to discuss their research and ideas for inquiry-based learning activities for high-school students. An Earth Institute news piece on the event is available here.


The workshop was organized by Jason Smerdon and international co-chairs Juerg Luterbacher and Steven Phipps. A local organizing committee also helped with the planning and execution of the meeting: Laia Andreu Hayles, Brendan Buckley, Rosanne D'Arrigo, Yochanan Kushnir, Justin Mankin, Richard Seager and Deepti Singh. Additional administrative coordination is being provided by Mercedes Paulino.


Kevin Anchukaitis (U of Arizona), Alyssa Atwood (UC Berkeley), Toby Ault (Cornell U), Seung Hun Baek (LDEO), Brendan Buckley (LDEO), Sloan Coats (CIRES), Kim Cobb (Georgia Tech), Ben Cook (NASA/GISS), Ed Cook (LDEO), Rosanne D'Arrigo (LDEO), Sylvia Dee (Brown U), Mike Evans (U of Maryland), Robert Field (NASA/GISS), Thomas Felis (U of Bremen), Ailie Gallant (Monash U), Michael Griffiths (William Paterson University), Laia Andreu Hayles (LDEO), Johann Jungclaus (MPI Hamburg), Bronwen Konecky (CIRES), Charuta Kulkarni (CUNY), Yochanan Kushnir (LDEO), Flavio Lehner (NCAR), Sophie Lewis (Austrailian National U), Allegra LeGrande (NASA/GISS), Caroline Leland (LDEO), Hans Linderholm (U of Gothenburg), Alex Lopatka (U of Maryland), Juerg Luterbacher (U of Giessen), Wenmin Man (Chinese Academy of Sciences), Justin Mankin (LDEO), Justin Maxwell (Indiana U), Atsushi Okazaki (U of Tokyo), Bette Otto-Bliesner (NCAR), Jonathan Palmer (U of New South Wales), Jud Partin (U of Texas), Eduardo Piovano (U of Córdoba), Steven Phipps (U of Tasmania), Christoph Raible (U of Bern), Mukund Rao (LDEO), Jack Scheff (LDEO), Gavin Schmidt (NASA/GISS), Richard Seager (LDEO), Deepti Singh (LDEO), Jason Smerdon (LDEO), Olga Solomina (Russian Academy of Sciences), Nathan Steiger (LDEO), Samantha Stevenson (NCAR), Jessica Tierney (U of Arizona), Martin Widmann (U of Birmingham), Davide Zanchettin (U of Venice), Huan Zhang (U of Giessen)

Image Credit: Francesco Fiondella

Travel and Accommodations

The workshop will be hosted at the Lamont-Doherty Earth Observatory, which is located just south of Palisades, NY. A block of rooms will available at the Holiday Inn in Orangeburg and hotel-to-workshop transport will be provided by the hotel. Flights should be arranged into Newark or Laguardia airports. Public transit is not available to the hotel and car service will be the best means of transport from the airports to Orangeburg. For those travelers who decide to stay in New York City, a shuttle bus is available to the Lamont campus on an hourly schedule. A majority of the meals will be catered and provided as part of the workshop funding. Additional informtation on travel and local logistics will be provided as they become available.


Ocean and Climate Physics
Lamont-Doherty Earth Observatory
Columbia University
61 Route 9W, P.O. Box 1000
Palisades, NY 10964
Phone: (845) 365-8373
pages2k.pmip3 [at] gmail [dot] com