QUEST research secondment from New Zealand to Cambridge

Between June and August 2018 I visited the Godwin Lab at the University of Cambridge as part of the QUEST project. This was an amazing, stimulating time for me where I learnt a lot and started some exciting work with Thomas Bauska and David Hodell. A new recruit to QUEST, PhD student Brittany Ward, also visited the lab overlapping with my visit and worked closely with Thomas in developing a new, fluid-inclusion isotope method for speleothems. The early results of Brittany’s work already look very promising and I received some very promising data from carbon and oxygen isotope analysis of a stalagmite record. The next step is to incorporate Ca isotopes and trace elements as proxies of local moisture availability.

Adam

Discussion article about a new vegetation proxy in speleothems and cave drip water published

Quest members from Mainz have published an article about the analysis of lignin oxidation products as vegetation proxies in speleothem and cave drip water samples in the discussion part of Biogeosciences. They developed a sensitive method to analyse the lignin composition of organic traces contained in speleothems. Lignin is a main constituent of woody plants and its composition contains information about the type of vegetation. This method offers new possibilities to reconstruct the vegetation of past millenia since it combines the advantages of lignin analysis as a highly specific vegetation biomarker with the benefits of speleothems as unique terrestrial climate archives.

Further reading:
https://www.biogeosciences-discuss.net/bg-2018-253/

Long Night of Science 2018

QUEST participated last year at the Long Night of Science – and it was a big success! This year we repeated and intensified our activities for the Long Night of Science in Potsdam and Berlin, and it was GREAT! As part of the “Climate Time Machine” exhibition Sebastian, Ola, and Norbert presented how we use stalagmites as palaeoclimate archives. To be better visible, we built a life-sized speleologist (cave researcher) and let him climb the stairways in the Michelson building (the main PIK building). We presented all the typical cave research stuff, caving gear, data loggers, surveying instruments, photographs of caves and active cave research, and selected stalagmite samples from our QUEST project. We received large interest, from interested researchers, parents and kids alike. The whole event was great fun and it was amazing to see that we can enthuse young pupils for our science. Science is much more than just numbers and computer models – and in our case really muddy, adventurous, and sportive.
Long Night of Science 2018

Long Night of Science 2018

 

Meet QUEST at EGU 2018

With the EGU General Assembly coming up next month, we have rounded up the first-author presentations from the people involved in QUEST. Most of the action takes place during Thursday and Friday (barring David Hodell’s presentation on Tuesday) and in Hall X5 and Room F2. Be sure to note this down in your calendar for the EGU week!

The topics are many, interesting, and diverse — they are sure to spark off interesting discussions and debate. Share this post with your colleagues and spread the word!


CL 1.11

Novel and quantitative methods for continental palaeoenvironmental reconstruction.

Orals: Thu, 12 Apr, 10:30–12:00 / Room 0.14
Posters: Attendance Thu, 12 Apr, 17:30–19:00 / Hall X5

IDTITLE & QUEST AUTHORSTYPE &
LOCATION
13780Towards a quantitative proxy of cave dripwater hydrology
Adam Hartland, Beth Fox, Sebastian Breitenbach
Poster, X5.251
12744Local and distant Pacific climate signals in cave hydrochemistry: Waipuna cave, New Zealand
Cinthya Nava, Adam Hartland, Bethany Fox, Sebastian Breitenbach
Poster, X5.250
979335,000 years of hydrological variability in northern New Zealand from speleothem magnetism
Bethany Fox, Ioan Lascu, Sebastian Breitenbach, Adam Hartland
Poster, X5.246
9046Tracing past shifts of the boundary between maritime and continental climate over Central Europe
Sebastian Breitenbach, Norbert Marwan
Poster, X5.245
15956Is this an event? - Detecting abrupt changes in palaeoclimate records
Bedartha Goswami, Sebastian Breitenbach, Norbert Marwan
Poster, X5.244

NP 2.4

New model and data-based approaches to study climate behavior

Orals: Fri, 13 Apr, 08:30–12:00 / Room M1
Posters: Attendance Fri, 13 Apr, 13:30–15:00 / Hall X4

IDTITLE & QUEST AUTHORSTYPE &
LOCATION
6190Detecting abrupt transitions during the Late Quaternary in southern Ethiopia using Recurrence Quantification Analyses
Hauke Krämer, Norbert Marwan
Oral, Room M1
15457Identifying sudden dynamical shifts in time series with uncertainties
Bedartha Goswami, Sebastian Breitenbach, Norbert Marwan
Poster, X4.277

 CL 1.17

The speleothem archive: understanding processes and interpreting Quaternary climate change

Orals: Thu, 12 Apr, 13:30–17:00 / Room 0.14
Posters:  Attendance Thu, 12 Apr, 17:30–19:00 / Hall X5

IDTITLE & QUEST AUTHORSTYPE &
LOCATION
16111Application of lignin analysis to flowstone, stalagmite and drip water samples – potentials of a new proxy
Inken Heidke, Denis Scholz, Thorsten Hoffmann
Poster, X5.286

CL1.06/GM8.12/HS1.19

Tackling past hydrological cycles – from local and regional to global scales (co-organized)

Orals: Fri, 13 Apr, 08:30–10:00 / Room F2
Posters:  Attendance Fri, 13 Apr, 17:30–19:00 / Hall X5

IDTITLE & QUEST AUTHORSTYPE &
LOCATION
19020Last Glacial Period hydrology of Lake Peten Itza (Guatemala) constrained with triple oxygen and hydrogen isotopes
Thomas Bauska, David Hodell
Oral,Room F2

CL 1.31

Climate response to orbital forcing (including Milutin Milankovic Medal Lecture)

Orals: Tue, 10 Apr, 13:30–17:00 / Room F2
Posters:  Attendance Tue, 10 Apr, 17:30–19:00 / Hall X5

IDTITLE & QUEST AUTHORSTYPE &
LOCATION
3858Integrating suborbital climate variability with classical Milanković theory
David Hodell
Oral, Room F2

Novel numerical method to analyse multivariate proxy records

Members of the QUEST team have published a new approach for analysing multivariate proxy records with recurrence networks. The idea is to first consider each proxy separately as a recurrence network, then combine them as layers of a multiplex network, and derive a similarity measure from this resulting multiplex recurrence network. This approach can be used to reveal periods of converging dynamics or very disperse variability, as demonstrated on an example of palaeo vegetation development during the last 16 ka in East Asia.

Multiplex recurrence network

Multiplex recurrence network

Further reading:
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.97.012312

New study on short time series published

The “inner composition alignment approach” (IOTA) has been suggested in the past for detecting interdependencies between short time series. QUEST members have now published a new study with a modification of this approach (called mIOTA). The new extension overcomes the drawbacks that IOTA is unable to distinguish between positive and negative correlations, and that the null distribution for IOTA is biased towards higher values. Although the new method cannot detect the direction of the interdependencies (unlike IOTA), it outperforms standard tools for detecting interdependencies (Pearson correlation, Spearman correlation, Kendall’s τ). The method is used to derive econo-climatic networks of interdependencies between economic indicators and climatic variability for Sub-Saharan Africa and South Asia including India.

Further reading:
http://www.ias.ac.in/describe/article/conf/001/01/0051-0060

Important step forward to recurrence analysis of data with uncertainties

In a new publication we propose a novel approach for analysing data with uncertainties, which is typical, e.g., in palaeoclimate observations. A time series of single values is replaced by a time series of probabilities; the binary matrix representation of recurrences is then replaced by  a matrix of probability values, which represent that a recurrence at a certain time appears. This approach is the base for a novel transition test, applying concepts from recurrence and complex network analysis. We demonstrate the potentials on examples from present-day climate (ENSO), palaeoclimate (Indian summer monsoon), and stock markets.

probability series

Time series of probability distributions of proxy values, allowing for uncertainty analysis.

Open access: https://www.nature.com/articles/s41467-017-02456-6