SISAL - Speleothem Isotopes Synthesis and AnaLysis



The Speleothem Isotope Synthesis and AnaLysis Working Group brings together speleothem scientists, speleothem-process and climate modelers to develop global synthesis of speleothem isotope and other proxies to explore past climate changes and for model evaluation.
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Twitter: @SISAL_wg


- Assess how cave monitoring data can improve the climatic interpretation of speleothem isotopic records.
- Explore the use of proxy-system and process-based modeling of oxygen and carbon isotopes to explain changes in speleothem isotopic records through time.
- Assess how trace elements can strengthen climatic interpretations of speleothem isotopic data in addition to providing independent palaeoclimatic and palaeoenvironmental information.
- Incorporate age-modeling uncertainties into the interpretation of proxy records.
- Draw on the various approaches listed in the objectives above to reconstruct past climate based on robust interpretations of the speleothem records for use in PMIP non-isotope enabled climate model evaluations.

Phase 1 products

- Publication of SISAL_v1 of the SISAL database (Atsawawaranunt et al. 2018) with 381 speleothem records from 174 cave sites and the associated database paper (Atsawawaranunt et al., 2018) in Earth System Science Data.
- Publication of a set of regional reviews of speleothem-based climate reconstructions in a Special Issue of Quaternary.
- Publication of a protocol to use SISAL for isotope-enabled model evaluation (Comas-Bru et al. 2019) accompanied by an updated version of the database (SISAL_v1b - Atsawawaranunt et al. 2019) in Climate of the Past.
- Publication of the second version of the SISAL database (SISAL_v2 - Comas-Bru et al. in prep) with 691 speleothem records from 293 cave sites. An important addition to SISAL_v2 is the construction of the "SISAL chronology": a suite of age models for ~500 speleothem records using 7 different approaches.
- See full list of products here.


Laia Comas-Bru (ECR; University of Reading, UK; lead coordinator)
Franziska Lechleitner (ECR; University of Bern, Switzerland; mailing list administrator)
Nikita Kaushal (ECR; Nanyang Technological University, Singapore)
Yassine Ait Brahim (ECR; Xi’an Jiaotong University, China)
Yuval Burstyn (ECR; Hebrew University of Jerusalem, Israel)
Brittany Marie Ward (ECR; University of Waikato, New Zealand)
Kerstin Braun (ECR; Arizona State University, USA)
Kira Rehfeld (Heidelberg University, Germany)
Sandy Harrison (University of Reading, UK)


Phase 2
Feb 2020
Feb 2024


sisal 2 group small
SISAL workshop at Xi’an Jiaotong University, China, in October 2019 - Synthesis of SISAL Phase 1 and planning for Phase 2. Photo Credit: Zhao Jingyao. Click to enlarge.

Speleothems are important sources of paleoclimate information because of their global distribution and exceptional age control.

In SISAL Phase 1 (2017-2020), the group built a global network of speleothem researchers and created a global database of speleothem oxygen and carbon isotopes. SISAL database version 2 has nearly 700 records, ~500 of which will additionally have standardized age models.

We used the SISAL database to review speleothem-based climate reconstructions regionally and provided a protocol for isotope-enabled model evaluation of speleothem data. However, many factors influence the isotopic composition of speleothems and robust interpretations remain a key gap. We plan to address this in SISAL Phase 2.

In SISAL Phase 2 (2020-2024), climatic interpretations will be improved using cave monitoring data and process-based modeling for the modern period and contiguous speleothem measurements, such as trace elements, and paleoclimate model simulations for periods beyond instrumental measurements.

Additionally, data assimilation techniques will be used to combine simulated and observed isotopic signals which can provide semi-quantitative climate reconstructions, allowing the SISAL database to be used for evaluation of climate models that do not explicitly simulate isotopes.

sisal 2 graphic new small web

Cave monitoring sites available in the database and speleothem records available in SISAL_v2 database (Comas-Bru et al. 2020a; 2020b) are plotted on a karst aquifer map of the world (Chen et al. 2017). European and Asian sites have been expanded in the panels below. Click to enlarge.

The SISAL Database

The SISAL database is the key product created by SISAL Phase 1 in 2018 and includes 381 speleothem records from 174 cave sites. This has been increased to nearly 700 speleothem records from 293 cave sites in SISAL_v2, which will be released in early 2020.

SISAL_v2 additionally contains 500 records with 'SISAL chronologies' - a suite of seven different methods used to construct age models enabling more accurate data synthesis and comparisons.

WG background

SISAL Phase 1 was active from 2017 to 2020. SISAL was initiated by Laia Comas-Bru and Sandy Harrison to provide quality controlled dataset versions of the vast number of published speleothem records for climate reconstruction and model evaluation.

SISAL is now an active speleothem community with over 100 members from 20+ countries who engage through annual workshops and monthly telecons to develop database versions and use them to answer big-picture science questions.

SISAL is led by a Steering Group and regional coordinators, and project specific leaders are largely composed of early-career researchers.

sisal 2 cave 2

Waipuna Cave, New Zealand. Image credit: Sebastian Breitenbach. Click to enlarge.

Learn more and participate

Subscribe to the SISAL mailing list here.

This group is open to anyone who is interested. To participate contact a member of the Steering Group.

Follow the working group on Twitter.