ORCID Profile
0000-0002-2387-4283
Current Organisation
Middle East Technical University
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Publisher: Mineralogical Society
Date: 07-2013
Publisher: Springer Science and Business Media LLC
Date: 29-10-2015
DOI: 10.1038/SREP15595
Abstract: Speleothem-based stable isotope records are valuable in sub-humid and semi-arid settings where many other terrestrial climate proxies are fragmentary. The Eastern Mediterranean is one such region. Here we present an 80-kyr-long precisely-dated (by U-series) and high-resolution oxygen (δ 18 O) and carbon (δ 13 C) records from Dim Cave (~36°N) in SW Turkey. The glacial-interglacial δ 18 O variations in the Dim Cave speleothem are best explained in terms of changes in the trajectories of winter westerly air masses. These are along a northerly (European) track (isotopically less depleted) during the early last glaciation but are gradually depressed southward closer to the modern westerly track along the North African coast (more depleted) after c.50 kyr and remain in the southern track through the Last Glacial Maximum. The southward displacement of the westerly track reflects growth of the Fennoscandian ice sheet and its impact on westerly wind fields. Changes in δ 13 C are interpreted as reflecting soil organic matter composition and/or thickness. δ 13 C values are significantly more negative in interglacials reflecting active carbonic acid production in the soil and less negative in glacial times reflecting carbonate rock values. Several Heinrich events are recorded in the Dim record indicating intensification of westerly flow across this part of the EM.
Publisher: Springer Science and Business Media LLC
Date: 04-09-2015
DOI: 10.1038/SREP13560
Abstract: Speleothem-based stable isotope records are valuable in sub-humid and semi-arid settings where many other terrestrial climate proxies are fragmentary. The Eastern Mediterranean is one such region. Here we present an 80-kyr-long precisely-dated (by U-series) and high-resolution oxygen (δ 18 O) and carbon (δ 13 C) records from Dim Cave (~36°N) in SW Turkey. The glacial-interglacial δ 18 O variations in the Dim Cave speleothem are best explained in terms of changes in the trajectories of winter westerly air masses. These are along a northerly (European) track (isotopically less depleted) during the early last glaciation but are gradually depressed southward closer to the modern westerly track along the North African coast (more depleted) after c.50 kyr and remain in the southern track through the Last Glacial Maximum. The southward displacement of the westerly track reflects growth of the Fennoscandian ice sheet and its impact on westerly wind fields. Changes in δ 13 C are interpreted as reflecting soil organic matter composition and/or thickness. δ 13 C values are significantly more negative in interglacials reflecting active carbonic acid production in the soil and less negative in glacial times reflecting carbonate rock values. Several Heinrich events are recorded in the Dim record indicating intensification of westerly flow across this part of the EM.
Publisher: American Geophysical Union (AGU)
Date: 07-2019
DOI: 10.1029/2018TC005450
Publisher: University of Queensland Library
Publisher: Wiley
Date: 10-02-2019
DOI: 10.1002/WAT2.1330
Abstract: The Fertile Crescent, its hilly flanks and surrounding drylands has been a critical region for studying how climate has influenced societal change, and this review focuses on the region over the last 20,000 years. The complex social, economic, and environmental landscapes in the region today are not new phenomena and understanding their interactions requires a nuanced, multidisciplinary understanding of the past. This review builds on a history of collaboration between the social and natural palaeoscience disciplines. We provide a multidisciplinary, multiscalar perspective on the relevance of past climate, environmental, and archaeological research in assessing present day vulnerabilities and risks for the populations of southwest Asia. We discuss the complexity of palaeoclimatic data interpretation, particularly in relation to hydrology, and provide an overview of key time periods of palaeoclimatic interest. We discuss the critical role that vegetation plays in the human–climate–environment nexus and discuss the implications of the available palaeoclimate and archaeological data, and their interpretation, for palaeonarratives of the region, both climatically and socially. We also provide an overview of how modelling can improve our understanding of past climate impacts and associated change in risk to societies. We conclude by looking to future work, and identify themes of “scale” and “seasonality” as still requiring further focus. We suggest that by appreciating a given locale's place in the regional hydroscape, be it an archaeological site or palaeoenvironmental archive, more robust links to climate can be made where appropriate and interpretations drawn will demand the resolution of factors acting across multiple scales. This article is categorized under: Human Water Water as Imagined and Represented Science of Water Water and Environmental Change Water and Life Nature of Freshwater Ecosystems
Publisher: Elsevier BV
Date: 12-2017
Publisher: Copernicus GmbH
Date: 14-09-0030
DOI: 10.5194/ESSD-10-1687-2018
Abstract: Abstract. Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide “out-of-s le” evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for in idual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (δ18O, δ13C) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data. The compiled data are available at 0.17864/1947.147.
Publisher: Elsevier BV
Date: 08-2016
Publisher: Elsevier BV
Date: 06-2016
Publisher: American Geophysical Union (AGU)
Date: 11-2019
DOI: 10.1029/2019GC008453
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 09-2013
Publisher: The Scientific and Technological Research Council of Turkey (TUBITAK-ULAKBIM) - DIGITAL COMMONS JOURNALS
Date: 15-01-2020
DOI: 10.3906/YER-1905-20
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 06-2019
Publisher: Duke University Press
Date: 2017
Abstract: This essay discusses the emergence of ecodiagrams focused on both representing and operating upon the changing relationship between “man” and “environment,” with an emphasis on the design methods of Hungarian American architects Victor and Aladar Olgyay. The architectural diagram became an important site for reconsidering the parameters of social transformation amid increasing knowledge of the fragility of the global ecological system. Of interest in the Olgyays’ diagrams, even more than the methods they proposed, are the conditions for the human that they imagined.
Publisher: Copernicus GmbH
Date: 09-08-2019
Abstract: Abstract. Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data–model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data–model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices.
Start Date: 2019
End Date: 2021
Funder: European Commission
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