DAPS 1st workshop: Proxy system modeling and data assimilation in paleosciences workshop

29.05 - 01.06.2017  
Louvain-la-Neuve, Belgium
Contact person:
Hugues Goosse, This email address is being protected from spambots. You need JavaScript enabled to view it.
Workshop report: 
> Access

PAGES' Paleoclimate Reanalyses, Data Assimilation and Proxy System modeling (DAPS) working group will hold its first workshop in Louvain-la-Neuve, Belgium, from 29 May to 1 June 2017.

The workshop is titled "Proxy system modeling and data assimilation in paleosciences."


The workshop will be held at Université catholique de Louvain and will be semi-open. Half of the expected 30 participants will be essential invitees identified to fulfill the goals of the workshop. The remaining places are left open for participants asking for an invitation based on relevant expertise or interest in the subject.


The first part of the workshop will consist of review talks by experts on data assimilation, modern and paleo reanalyses, and on the comparison of model results and different types of data (over land and in the oceans) using models representing directly the observed variables. Some discussions will be planned to identify the main issues to be solved and the best opportunities for the coming years.

In the second part, training will be provided, including some practical activities on computers using proxy system models and simple data assimilation routines. Code repositories currently exist and workshop participants will be encouraged to deposit a versioned code on such repositories to facilitate joined activities, to encourage new users to develop applications and stimulate collaborations. This will be achieved in preparation for the workshop and as a legacy of the activity. This second part mainly targets young scientists and senior scientists who do not have experience yet in the domain, but would like to apply some of the techniques in their work.

Workshop aims

The workshop will have two main goals. The first is to propose an overview of current activities in Paleoclimate Reanalyses, Data Assimilation and Proxy System modeling. The second will be to stimulate new activities in those fields and identify the topics where rapid progresses can be obtained. Key examples of application (existing or that can be developed on short term) that demonstrate the interest of the approaches and can be used easily by a wider group of scientists will also be identified.


Monday 29 May
9.30 Welcome, introduction, objectives of the workshop: Hugues Goosse, Mike Evans, Samar Khatiwala
10.00-12.30 Overview talks:
10.00-10.30 Dick Dee. Modern reanalysis as a framework for paleoclimate data assimilation
10.30-11.00 Mike Evans. Pathologies of paleoenvironmental data
11.00-11.30 Sylvia Dee. Proxy system (data) models in paleoclimatology
11.30-12.00 Alexandra Jahn, Martin Werner. Isotope modeling
12.00-12.30 Discussion: Paleoenvironmental DA: how broken are the assumptions?
12.30-13.30 Lunch
13.30-16.00 DA-based paleoenvironmental reconstructions: modern frameworks and current challenges:
13.30-14.00 Greg Hakim, Michel Crucifix, Martin Widmann. Frameworks for paleoclimate reconstructions DA
14.00-14.30 Jörg Franke. Reconstruction of atmospheric and surface conditions
14.30-15.00 Andre Paul, Didier Swingedouw, Akira Oka. Reconstruction of ocean conditions
15.00-15.30 Fabio Gennaretti. Reconstruction based on information from ecosystems. Sandy Harrison Physiology-based modelling of productivity and tree growth
15.30-16.00 Discussion: what is to be gained from a generalized framework for atmosphere, ocean and ecosystem DA?
16:00-16.30 Coffee break
16:30-17.00 Organization of working groups:
1. What initiatives would most improve the utility of proxy system models in observation-simulation comparisons and for paleoenvironmental data assimilation?
2. What would an idealized (practical) code and data platform look like? What are the most important shared or common elements? What elements should be developed separately?
3. How can communities working on somewhat different targeted product variable subsets (e.g. physical atmosphere, physical ocean, atmosphere/ocean chemistry, terrestrial/marine ecosystems), realms (ocean, atmosphere, cryosphere, biosphere), time scales (annual to millennial resolution) learn from each other?
17.30 Ice breaker

Tuesday 30 May
9.00-10.00 Proxy system models: development, validation, applications:
9.00-9.15 Scott St. George. Why do trees remember? Discerning biological and climatic persistence within tree-ring width chronologies and the global tree-ring network
9.15-9.30 Anne Mouchet. How well do benthic-planktonic radiocarbon ages approximate ocean ventilation? Impact of air-sea exchange, transfer functions and atmospheric levels
9.30-9.45 Branwen Williams. Coralline algae: using a multi-pronged approach to extracting environmental signals from a sub-annually resolved, high-latitude climate archive
9.45-10.00 Discussion
10.00-10.30 Coffee break
10.30-11.30 Proxy system models: development, validation, applications:
10.30-10.45 Diane Thompson. Towards improved coral proxy system models (PSMs)
10.45-11.00 Matt Jones. Towards data model comparison using lake isotope PSMs
11.00-11.15 Corine Wong. Assessing proxy system models of cave dripwater δ18O variability
11.15-11.30 Discussion
11.30-13.00 Working group discussions
13.00-14.00 Lunch
14.00-14.30 Synthesis of the working group discussions
14.30-15.30 Paleoenvironmental data assimilation: development, validation, applications:
14.30-14.45 Samar Khatiwala. The transport matrix method
14.45-15.00 Atsushi Okazaki. Development and evaluation of isotopic proxy data assimilation system
15.00-15.15 Joel Guiot. Offline data assimilation using pollen data, LOVECLIM and BIOME4 models
15.15-15.30 Martin Widmann. Assimilation of PAGES2k continental temperature reconstructions with a GCM
15.30-15.45 Discussions
15.45-16.00 Coffee break
16.00-17.30 Poster session
17.30-18.00 Overview and objectives of the practicals
19.00 Group dinner

Wednesday 31 May
9.00-10.30 Working group meetings – outcomes of the workshop
10.30-11.00 Coffee Break
11.00-12.30 Working group reports: recommendations for key foci for future activities
14.00-17.30 Class room practicals: Demonstration of Prysm (climate proxy system modeling tools in python) and practical applications

Thursday 1 June
9.00-12.30 Class room practicals: Parameter and state estimation using a classical energy balance model, or
Ecophysiological modeling of the climate imprint on photosynthesis and carbon allocation to the tree stem in the North American boreal forest
14.00-17.30 Class room practicals: Reconstructing surface temperature over the last centuries using off line data assimilation

Further information

Go to the DAPS homepage or contact Hugues Goosse: This email address is being protected from spambots. You need JavaScript enabled to view it.

Post-meeting material

> Introduction to workshop

Overview talks

> Modern reanalysis: A framework for paleoclimate data assimilation? D. Dee
> The peculiar properties of paleoclimate data M. Evans
> Data Assimilation in Paleosciences Reconstruction of Atmospheric and Surface Conditions J. Franke
> Ecophysiological modeling of tree primary production and carbon allocation in a Canadian boreal region F. Gennaretti
> Frameworks for Paleoclimate Reconstructions DA G. Hakim
> Physiology-based modelling of productivity and tree growth S. Harrison
> Explicit isotope modeling with CESM and ECHAM/MPI-OM A. Jahn
> The Transport Matrix Method (TMM) (for fast, offline simulation of passive tracers in the ocean) S. Khatiwala
> How well do proxy system (data) models simulate real paleoclimate observations? T. Laepple
> Proxy modelling for the glacial AMOC reconstruction: a brief review on Pa/Th and εNd simulation A. Oka
> Dynamical reconstruction of the global ocean state during the Last Glacial Maximum A. Paul
> Reconstructing the ocean through surface nudging D. Swingedouw
> Assimilation of PAGES 2k temperature reconstructions with a GCM M. Widmann
> Explicit modelling of water isotopes within ECHAM5/MPI-OM M. Werner

Short talks

> Quantifying Uncertainties in Paleoclimate Reconstruction A case study over the past 800 kyr J. Carson
> Model selection, parameter and state estimation with uncertain chronology M. Crucifix
> Ecophysiological modeling of tree primary production and carbon allocation with MAIDEN F. Gennaretti
> Offline data assimila-on using pollen data, LOVECLIM and BIOME4 models J. Guiot
> Towards data model comparison using lake isotope PSMs M. Jones
> Development and evaluation of isotopic proxy data assimilation system A. Okazaki
> Development and evaluation of a system of proxy data assimilation for paleoclimate reconstruction A. Okazaki
> Towards improved coral proxy system models (PSMs) D. Thompson
> Coralline algae: using a multipronged approach to extracting environmental signals from a high-latitude climate archives B. Williams
> Assessing proxy system models of dripwater δ18O variability C. Wong


> SISAL: A community-driven initiative to create a global database of speleothem isotopic data for paleoclimate model evaluation, L. Comas Bru
> Improving global ocean simulations by assimilation of SMART cable measurements, T. Weber
> How informative is paleoceanographic data? - Insights from putting classical inverse problems into a Bayesian perspective, N. Loose
> Compiling a global high-resolution paleoclimate database for MIS-3: challenges and opportunities, J. Pedro
> Proxy system models for sediment and ice archived proxies and strategy to use and perform field observations to constrain proxy system models, T. Laepple
> A dynamical reconstruction of the ocean state constrained by global d¹⁸O data, C. Breitkreuz
> Annual to multidecadal coherence of Atlantic meridional heat transport in last-millennium CMIP5 simulations and the Last Millennium Reanalysis, D. Amrhein
> New multi proxy technique for reconstructing evaporation and aridity using triple oxygen isotopes and clumped isotopes in carbonates, J. Moermann
> Directly assimilate proxy in paleoclimate data assimilation: a case study in High-Asia air temperature reconstruction M. Fang
> Data assimilation of water stable isotopes from Antarctic ice cores over the last three centuries, F. Klein
> Assessing ocean circulation changes at the LGM using radiocarbon simulations with the iCESM, A. Schroeder

Group discussions

> DAPS Integrated assessment
> Biases