Percorrer por autor "Harrison, Sandy P."
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- Evaluating model outputs using integrated global speleothem records of climate change since the last glacialPublication . Comas-Bru, Laia; Harrison, Sandy P.; Werner, Martin; Rehfeld, Kira; Scroxton, Nick; C. Veiga-Pires, C.; 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, István Gábor; 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; Finne, 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, HaiweiAlthough 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.
- The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial periodPublication . Goni, Maria F. Sanchez; Desprat, Stephanie; Daniau, Anne-Laure; Bassinot, Frank C.; Polanco-Martinez, Josue M.; Harrison, Sandy P.; Allen, Judy R. M.; Anderson, R. Scott; Behling, Hermann; Bonnefille, Raymonde; Burjachs, Francesc; Carrion, Jose S.; Cheddadi, Rachid; Clark, James S.; Combourieu-Nebout, Nathalie; Mustaphi, Colin. J. Courtney; Debusk, Georg H.; Dupont, Lydie M.; Finch, Jemma M.; Fletcher, William J.; Giardini, Marco; Gonzalez, Catalina; Gosling, William D.; Grigg, Laurie D.; Grimm, Eric C.; Hayashi, Ryoma; Helmens, Karin; Heusser, Linda E.; Hill, Trevor; Hope, Geoffrey; Huntley, Brian; Igarashi, Yaeko; Irino, Tomohisa; Jacobs, Bonnie; Jimenez-Moreno, Gonzalo; Kawai, Sayuri; Kershaw, A. Peter; Kumon, Fujio; Lawson, Ian T.; Ledru, Marie-Pierre; Lezine, Anne-Marie; Liew, Ping Mei; Magri, Donatella; Marchant, Robert; Margari, Vasiliki; Mayle, Francis E.; McKenzie, G. Merna; Moss, Patrick; Mueller, Stefanie; Mueller, Ulrich C.; Naughton, Filipa; Newnham, Rewi M.; Oba, Tadamichi; Perez-Obiol, Ramon; Pini, Roberta; Ravazzi, Cesare; Roucoux, Katy H.; Rucina, Stephen M.; Scott, Louis; Takahara, Hikaru; Tzedakis, Polichronis C.; Urrego, Dunia H.; van Geel, Bas; Valencia, B. Guido; Vandergoes, Marcus J.; Vincens, Annie; Whitlock, Cathy L.; Willard, Debra A.; Yamamoto, MasanobuQuaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st-century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard-Oeschger (D-O) cycles during the last glacial period, which were sufficiently large to have had a potential feedback through changes in albedo and greenhouse gas emissions on climate. Previous reconstructions of vegetation and fire changes during the D-O cycles used independently constructed age models, making it difficult to compare the changes between different sites and regions. Here, we present the ACER (Abrupt Climate Changes and Environmental Responses) global database, which includes 93 pollen records from the last glacial period (73-15 ka) with a temporal resolution better than 1000 years, 32 of which also provide charcoal records. A harmonized and consistent chronology based on radiometric dating (C-14, U-234/Th-230, optically stimulated luminescence (OSL), Ar-40/Ar-39-dated tephra layers) has been constructed for 86 of these records, although in some cases additional information was derived using common control points based on event stratigraphy. The ACER database compiles metadata including geospatial and dating information, pollen and charcoal counts, and pollen percentages of the characteristic biomes and is archived in Microsoft Access (TM) at https://doi. org/10.1594/PANGAEA. 870867.
- The SISAL database: a global resource to document oxygen and carbon isotope records from speleothemsPublication . 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; Lechleiter, Franziska A.; Lorrey, Andrew; Pérez-Mejías, Carlos; Pickering, Robyn; Scroxton, Nick; Veiga-Pires, C.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 youngest part 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 about the full range of measurements carried out on each speleothem and information about the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data.