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5 results on '"Veiga Pires, Cristina"'

1. Global reorganization of atmospheric circulation during Dansgaard–Oeschger cycles.

Author

Fohlmeister, Jens, Sekhon, Natasha, Columbu, Andrea, Vettoretti, Guido, Weitzel, Nils, Rehfeld, Kira, Veiga-Pires, Cristina, Ben-Yami, Maya, Marwan, Norbert, and Boers, Niklas

Subjects
ATMOSPHERIC circulation, CLIMATE change, ATMOSPHERIC models, ICE cores, GLACIAL climates
Abstract

Ice core records from Greenland provide evidence for multiple abrupt cold–warm– cold events recurring at millennial time scales during the last glacial interval. Although climate variations resembling Dansgaard–Oeschger (DO) oscillations have been identified in climate archives across the globe, our understanding of the climate and ecosystem impacts of the Greenland warming events in lower latitudes remains incomplete. Here, we investigate the influence of DO-cold-to-warm transitions on the global atmospheric circulation pattern. We comprehensively analyze δ18O changes during DO transitions in a globally distributed dataset of speleothems and set those in context with simulations of a comprehensive high-resolution climate model featuring internal millennial-scale variations of similar magnitude. Across the globe, speleothem δ18O signals and model results indicate consistent large-scale changes in precipitation amount, moisture source, or seasonality of precipitation associated with the DO transitions, in agreement with northward shifts of the Hadley circulation. Furthermore, we identify a decreasing trend in the amplitude of DO transitions with increasing distances from the North Atlantic region. This provides quantitative observational evidence for previous suggestions of the North Atlantic region being the focal point for these archetypes of past abrupt climate changes. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Evaluating model outputs using integrated global speleothem records of climate change since the last glacial

Author

Comas-Bru, Laia, Harrison, Sandy P., Werner, Martin, Rehfeld, Kira, Scroxton, Nick, Veiga-Pires, Cristina, Ahmad, Syed Masood, Brahim, Yassine Ait, Mozhdehi, Sahar Amirnezhad, Arienzo, Monica, Atsawawaranunt, Kamolphat, Baker, Andy, Braun, Kerstin, Breitenbach, Sebastian, Burstyn, Yuval, Chawchai, Sakonvan, Columbu, Andrea, Deininger, Michael, Demeny, Attila, Dixon, Bronwyn, Hatvani, Istvan Gabor, Hu, Jun, Kaushal, Nikita, Kern, Zoltan, Labuhn, Inga, Lachniet, Matthew S., Lechleitner, Franziska A., Lorrey, Andrew, Markowska, Monika, Nehme, Carole, Novello, Valdir F., Oster, Jessica, Perez-Mejias, Carlos, Pickering, Robyn, Sekhon, Natasha, Wang, Xianfeng, Warken, Sophie, Atkinson, Tim, Ayalon, Avner, Baldini, James, Bar-Matthews, Miryam, Bernal, Juan Pablo, Boch, Ronny, Borsato, Andrea, Boyd, Meighan, Brierley, Chris, Cai, Yanjun, Carolin, Stacy, Cheng, Hai, Constantin, Silviu, Couchoud, Isabelle, Cruz, Francisco, Denniston, Rhawn, Dragusin, Virgil, Duan, Wuhui, Ersek, Vasile, Finné, Martin, Fleitmann, Dominik, Fohlmeister, Jens, Frappier, Amy, Genty, Dominique, Holzkamper, Steffen, Hopley, Philip, Johnston, Vanessa, Kathayat, Gayatri, Keenan-Jones, Duncan, Koltai, Gabriella, Li, Ting-Yong, Lone, Mahjoor Ahmad, Luetscher, Marc, Mattey, Dave, Moreno, Ana, Moseley, Gina, Psomiadis, David, Ruan, Jiaoyang, Scholz, Denis, Sha, Lijuan, Smith, Andrew Christopher, Strikis, Nicolas, Treble, Pauline, Unal-Imer, Ezgi, Vaks, Anton, Vansteenberge, Stef, Voarintsoa, Ny Riavo G., Wong, Corinne, Wortham, Barbara, Wurtzel, Jennifer, Zhang, Haiwei, Voarintsoa, Ny Riavo, Earth Observatory of Singapore, Comas-Bru L., Harrison S.P., Werner M., Rehfeld K., Scroxton N., Veiga-Pires C., Ahmad S.M., Brahim Y.A., Mozhdehi S.A., Arienzo M., Atsawawaranunt K., Baker A., Braun K., Breitenbach S., Burstyn Y., Chawchai S., Columbu A., Deininger M., Demeny A., Dixon B., Hatvani I.G., Hu J., Kaushal N., Kern Z., Labuhn I., Lachniet M.S., Lechleitner F.A., Lorrey A., Markowska M., Nehme C., Novello V.F., Oster J., Perez-Mejias C., Pickering R., Sekhon N., Wang X., Warken S., Atkinson T., Ayalon A., Baldini J., Bar-Matthews M., Bernal J.P., Boch R., Borsato A., Boyd M., Brierley C., Cai Y., Carolin S., Cheng H., Constantin S., Couchoud I., Cruz F., Denniston R., Dragusin V., Duan W., Ersek V., Finne M., Fleitmann D., Fohlmeister J., Frappier A., Genty D., Holzkamper S., Hopley P., Johnston V., Kathayat G., Keenan-Jones D., Koltai G., Li T.-Y., Lone M.A., Luetscher M., Mattey D., Moreno A., Moseley G., Psomiadis D., Ruan J., Scholz D., Sha L., Smith A.C., Strikis N., Treble P., Unal-Imer E., Vaks A., Vansteenberge S., Voarintsoa N.R.G., Wong C., Wortham B., Wurtzel J., and Zhang H.

Subjects
010506 paleontology, Climate Research, 010504 meteorology & atmospheric sciences, δ18O, lcsh:Environmental protection, Climate Change, Stratigraphy, Speleothem, Climate change, F800, PMIP4 CONTRIBUTION, Geology [Science], 01 natural sciences, Klimatforskning, STABLE-ISOTOPE VARIATIONS, lcsh:Environmental pollution, Time windows, ddc:550, Meteorology & Atmospheric Sciences, lcsh:TD169-171.8, Speleothem Records, GENERAL-CIRCULATION MODEL, ASIAN MONSOON, Glacial period, Geosciences, Multidisciplinary, DELTA-O-18 WATER ISOTOPE, Baseline (configuration management), lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, Global and Planetary Change, geography, Coupled model intercomparison project, Science & Technology, geography.geographical_feature_category, Paleontology, Geology, GROWTH FREQUENCY VARIATIONS, NORTH-ATLANTIC, OXYGEN-ISOTOPE, 13. Climate action, Climatology, lcsh:TD172-193.5, Physical Sciences, Spatial ecology, Environmental science, Institut für Geowissenschaften, ATMOSPHERIC CIRCULATION, HIGH-RESOLUTION
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 delta O-18 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 delta O-18 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. European Geosciences Union - W2017/413; Irish Centre for Research in Applied Geosciences (iCRAG); European Association of Geochemistry (Early Career Ambassadors program 2017); Quaternary Research Association UK; Navarino Environmental Observatory, Stockholm University; University College Dublin, Savillex (UK) - SF1428; Ibn Zohr University, Morocco; University of Reading; European Research Council - 694481; Natural Environment Research Council (JPI-Belmont project "PAleao-Constraints on Monsoon Evolution and Dynamics (PACMEDY)"); Geological Survey Ireland - 2017-SC-056; Royal Irish Academy; Deutsche Forschungsgemeinschaft - RE3994/2-1; Past Global Changes (PAGES) programme; info:eu-repo/semantics/publishedVersion

Published
2019

3. The SISAL database: a global resource to document oxygen and carbon isotope records from speleothems

Author

Atsawawaranunt, Kamolphat, Comas-Bru, Laia, Mozhdehi, Sahar Amirnezhad, Deininger, Michael, Harrison, Sandy P., Baker, Andy, Boyd, Meighan, Kaushal, Nikita, Ahmad, Syed Masood, Brahim, Yassine Ait, Arienzo, Monica, Bajo, Petra, Braun, Kerstin, Burstyn, Yuval, Chawchai, Sakonvan, Duan, Wuhui, Hatvani, Istvan Gabor, Hu, Jun, Kern, Zoltan, Labuhn, Inga, Lachniet, Matthew, Lechleitner, Franziska A., Lorrey, Andrew, Perez-Mejias, Carlos, Pickering, Robyn, Scroxton, Nick, Atkinson, Tim, Ayalon, Avner, Baldini, James, Bar-Matthews, Miriam, Pablo Bernal, Juan, Breitenbach, Sebastian, Boch, Ronny, Borsato, Andrea, Cai, Yanjun, Carolin, Stacy, Cheng, Hai, Columbu, Andrea, Couchoud, Isabelle, Cruz, Francisco, Demeny, Attila, Dominguez-Villar, David, Dragusin, Virgil, Drysdale, Russell, Ersek, Vasile, Finné, Martin, Fleitmann, Dominik, Fohlmeister, Jens, Frappier, Amy, Genty, Dominique, Holzkamper, Steffen, Hopley, Philip, Kathayat, Gayatri, Keenan-Jones, Duncan, Koltai, Gabriella, Luetscher, Marc, Li, Ting-Yong, Lone, Mahjoor Ahmad, Markowska, Monika, Mattey, Dave, McDermott, Frank, Moreno, Ana, Moseley, Gina, Nehme, Carole, Novello, Valdir F., Psomiadis, David, Rehfeld, Kira, Ruan, Jiaoyang, Sekhon, Natasha, Sha, Lijuan, Sholz, Denis, Shopov, Yavor, Smith, Andrew, Strikis, Nicolas, Treble, Pauline, Unal-Imer, Ezgi, Vaks, Anton, Vansteenberge, Stef, Veiga-Pires, Cristina, Voarintsoa, Ny Riavo, Wang, Xianfeng, Wong, Corinne, Wortham, Barbara, Wurtzel, Jennifer, Zong, Baoyun, Veiga-Pires, C., Atsawawaranunt, Kamolphat, Comas-Bru, Laia, Amirnezhad Mozhdehi, Sahar, Deininger, Michael, Harrison, Sandy P., Baker, Andy, Boyd, Meighan, Kaushal, Nikita, Ahmad, Syed Masood, Ait Brahim, Yassine, Arienzo, Monica, Bajo, Petra, Braun, Kerstin, Burstyn, Yuval, Chawchai, Sakonvan, Duan, Wuhui, Hatvani, István Gábor, Hu, Jun, Kern, Zoltán, Labuhn, Inga, Lachniet, Matthew, Lechleitner, Franziska A., Lorrey, Andrew, Pérez-Mejías, Carlo, Pickering, Robyn, Scroxton, Nick, and Tim Atkinso, Avner Ayalon, James Baldini, Miriam Bar-Matthews, Juan Pablo Bernal, Sebastian Breitenbach, Ronny Boch, Andrea Borsato, Yanjun Cai, Stacy Carolin, Hai Cheng, Andrea Columbu, Isabelle Couchoud, Francisco Cruz, Attila Demény, David Dominguez-Villar, Virgil Dragusin, Russell Drysdale, Vasile Ersek, Martin Finné, Dominik Fleitmann, Jens Fohlmeister, Amy Frappier, Dominique Genty, Steffen Holzkämper, Philip Hopley, Gayatri Kathayat, Duncan Keenan-Jones, Gabriella Koltai, Marc Luetscher, Ting-Yong Li

Subjects
010506 paleontology, Climate Research, 010504 meteorology & atmospheric sciences, Climate change, Speleothem, F800, 010502 geochemistry & geophysics, computer.software_genre, 01 natural sciences, Klimatforskning, Cave, Paleoclimatology, lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, geography, geography.geographical_feature_category, Database, Stable isotope ratio, speleothems, PALEOCLIMATOLOGIA, lcsh:QE1-996.5, lcsh:Geology, Metadata, 13. Climate action, General Earth and Planetary Sciences, Environmental science, Climate model, computer, Chronology
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-sample” 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 individual 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 https://doi.org/10.17864/1947.147.

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4. High-resolution digital 3D models of Algar do Penico Chamber: limitations, challenges, and potential.

Author

Silvestre, Ivo, Rodrigues, José I., Figueiredo, Mauro, and Veiga-Pires, Cristina

Subjects
*GEOMORPHOLOGY, *HIGH resolution imaging, *HYDROLOGY, *CLIMATE change, *GEOLOGICAL time scales, *OPTICAL scanners, *KARST
Abstract

The study of karst and its geomorphological structures is important for understanding the relationships between hydrology and climate over geological time. In that context, we conducted a terrestrial laser-scan survey to map geomorphological structures in the karst cave of Algar do Penico in southern Portugal. The point cloud data set obtained was used to generate 3D meshes with different levels of detail, allowing the limitations of mapping capabilities to be explored. In addition to cave mapping, the study focuses on 3D-mesh analysis, including the development of two algorithms for determination of stalactite extremities and contour lines, and on the interactive visualization of 3D meshes on the Web. Data processing and analysis were performed using freely available open-source software. For interactive visualization, we adopted a framework based on Web standards X3D, WebGL, and X3DOM. This solution gives both the general public and researchers access to 3D models and to additional data produced from map tools analyses through a web browser, without the need for plug-ins. [ABSTRACT FROM AUTHOR]

Published
2015
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5. Global patterns of climate change since the Last Glacial from speleothem records.

Author

Comas-Bru, Laia, Harrison, Sandy P., Werner, Martin, Brierley, Chris, Rehfeld, Kira, Scroxton, Nick, Veiga-Pires, Cristina, and Amirnezhad-Mozhdehi, Sahar

Subjects
*SPELEOTHEMS, *CLIMATE change, *LAST Glacial Maximum, *TRACERS (Chemistry), *OXYGEN isotopes, *STABLE isotope analysis
Abstract

Speleothems (cave carbonates) provide highly resolved records with the potential toreconstruct past changes in mean regional climate and climate variability on annual tomillennial timescales. The most common type of measurements made on speleothems – thestable isotopes of oxygen (δ18O) – can be used to evaluate climate models that explicitlyinclude isotopic tracers, although this has rarely been done because of the lack of a globalsynthesis of the records.Here we compare speleothem isotope data from the SISAL (Speleothem Isotopes Synthesisand Analysis) database and the outputs of the isotope-enabled ECHAM5-wiso model for theLast Glacial Maximum (21 ka), the Mid-Holocene (6ka) and the modern (1850 – 2013)periods. We show how the SISAL database compares to GNIP (Global Network of Isotopesin Precipitation) measurements and model outputs in terms of temporal variability, the abilityof ECHAM5-wiso to reproduce the SISAL observations both globally and for several keytransects during the Mid-Holocene and the Last Glacial Maximum, and the extent to whichthe speleothem age-depth model uncertainties impact the mean isotope values obtained forthe LGM.We also highlight the use of metadata included in the SISAL database to screen thepaleorecords used for such data-model comparisons. Finally, we will discuss the benefits andweaknesses of using speleothem records for data-model comparisons and how ourapproach can be applied to assess other isotope-enabled climate model simulations. [ABSTRACT FROM AUTHOR]

Published
2019

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