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Leadership team notes

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Paleodata metadatabase development and analysis

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O2kP2update, PAGES-MARPA, AURA2k, Iso2k-salinity



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"Updating the Ocean2k metadatabase for Phase 2 projects" - Ocean2k is built on synthesising reconstructions that span some or all of the past 2000 years (2k). An essential step in this process is knowing what paleoclimate reconstructions are available and where the data can be accessed. "Native bi-centennial resolution data"  - Investigation of native bicentennial-resolution datasets; calibrations change and are uncertain; explore the effect of calibrations on results; for O2k sites with delta18O, important to have native data, since it’s temperature-sensitive, and use it jointly with Mg/Ca to solve for temperature and delta18Osw.


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"Addressing data and physical sample management needs of researchers using marine annually-resolved proxy archives" - What are the best methods to share data electronically and to manage physical specimens for data producers (paleoclimatogists, geologists, etc.), and data users (statistical climatologists, climate modelers, etc.) in the worldwide community of today’s and future researchers?


"Assessing uncertainties in radiocarbon derived age models" - Implications of utilising different 14C calibration packages (OxCal, BChron and Bacon) and calibration techniques (marine and atmospheric calibration curves, e.g. IntCal 13 and Marine 13; incorporation of regional marine radiocarbon reservoir offsets, ΔR) in the generation of robust sediment core records and whether improved radiocarbon calibration and tuning techniques could constrain uncertainties in sediment core age models and lead to a better understanding of the timing and spatial coherence of past oceanographic variability.


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"Improved understanding of ocean salinity change and the global water cycle for the past 2k (synthesise published salinity reconstructions)" - How do isotope proxy records capture long-term trends associated with changes in the water cycle at low latitudes? Create a global database of stable oxygen and hydrogen isotope records that researchers can use to assess regional- and global-scale changes in rainfall and atmospheric/oceanic circulation patterns during the past 2k.


Tropical Observations and dynamiCs = TropicalOC2k

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Tropical_Pacific, ENSO_flavours, Teleconnection_stability, IPO_reconstruction



"The role of the tropical oceans in past changes in Hadley circulation strength" - How have the latitudinal climate belts shifted (expanded, contracted) over time, and what does this tell us about recent temperature and rainfall trends in both hemispheres?


"Spatial dynamics of ENSO during the pre-industrial period" - Accounting for the spatial distribution of a high-resolution palaeoclimate network will not only help understand the temporal evolution of SST anomalies, but also provides a new opportunity to characterise features such as the onset, duration and spatial extent ENSO events over past centuries from the recently consolidated dataset.


"Teleconnection stability over the last centuries" - Addressing whether some of the most important teleconnection patterns were stable over the last centuries. And, if not, how often and in what way the teleconnections changed over time. This is crucial for the understanding of past, present and future climate as many quantifications of regional to global climate variability are based on the assumption of stable teleconnection patterns.


"Reconstructing the Interdecadal Pacific Oscillation (IPO)" - The primary science question is understanding how the IPO/PDO has varied in the pre-instrumental period, focussing on the most recent several centuries, when high-resolution palaeoclimate data is most available and reliable. With the limited representation of low-frequency variations in SST available in the instrumental period, a reliable palaeoclimate representation of the IPO in recent centuries is important to our understanding of hiatus and accelerated warming periods.


North Atlantic Observations and dynamiCs = NAtlOC2k

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"The reconstruction of climate variability in the North Atlantic using natural archives of marine and terrestrial ecosystems" - Identify and evaluate high resolution timeseries of ecosystems variables, including fisheries records and chronologies constructed from precisely dated fish otoliths, that can be combined with tree-ring and shell increment chronologies to provide insights into climate variability in the North Atlantic region during the past 1000 years.


"Deciphering NE Atlantic multidecadal variability by analyzing annual-to-decadal resolution marine proxy records and numerical models" - Identify and investigate key mechanisms of North Atlantic multidecadal variability by analyzing state-of-the-art climate model simulations, high-resolution (sclerochronological and sedimentary) paleoclimate reconstructions covering the last few centuries.


"To what extent can observed and predicted AMOC variability be distiguished from the natural variability during the 2k interval?" - Using the proxy surrogate reconstruction (PSR) method, we will combine the marine paleoclimate data described in the O2k paleodata metadatabase (primarily d18O and temperature proxies) with the equivalent variables derived or calculated from CMIP5 simulations to reconstruct centennial-scale AMOC variability. We will also develop pseudopproxy experiments (PPEs), for which the only unconstrained variables are parameter estimates required for closing the PSR (observational location, simulation ensemble member, observational uncertainty, similarity index), to estimate by analogy the precision and accuracy of the actual PSR. PPEs may also be employed to identify priority sites for future work. The role of external radiative forcing in explaining the results will be assessed by comparing PSRs using last millennium simulations to those using unforced control runs.


"Changes in the Atlantic Meridional Overturning Circulation over the past 2k" - Use the available ocean surface temperature proxy records from the North Atlantic region as a potential indicator for AMOC strength changes over the past 2k and infer past AMOC variability by analyzing proxy records of changes in the properties of the deep and intermediate waters that form in the Nordic Seas and Labrador Sea, such as the Nordic Overflows, the Deep Western Boundary Current and the Labrador Sea Water and that constitute the deep limb of the AMOC.


"The extension and strengthening of the Arctica islandica chronology for the North Icelandic Shelf" - An essential step to the achievement of a fully coupled marine-terrestrial reconstruction for the past 2k is the rapid development of long annually resolved marine proxy archives.


"Evaluating the potential for developing 1000-year long sclerochronologies in the NE Atlantic" - Within several on-going activities, e.g. ITN ARAMACC (Annual Resolved Records of Marine Climate Change) and Norwegian Research Council project ECHO (Extending the instrumental record of North Atlantic Ocean climate variability), sclerochronologies from sites in the northeastern North Atlantic and in the Norwegian Sea are being developed. These chronologies will initially be quite short, the goals being that the chronologies span the last 300 years. Construction of longer chronologies is both time consuming and challenging. As these shorter chronologies advance, the sites need to be evaluated according to their potential to provide enough material for 1000-year long chronologies and climatologically important data, and to allow robust calibration/verification procedures between proxy data and seawater instrumental series.


Mediterranean Observations and dynamiCs = MedOC2k

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PaleoMex2k, EuroMed2k-O2k



"Paleo-Mediterranean Experiment 2k" - Explore the multi-decadal variability embedded in high-resolution paleoclimatic reconstructions to investigate the Europe/Mediterranean climate variability and the role of North Atlantic ocean SSTs . We will use selected/reference continental and marine archives and apply statistical tools to analyze the spatial pattern of SSTs and assess link with AMO, mode of atmospheric variability and/or weather regimes. We will compare the reconstructions to simulations of the last millennium of the IPSL-CM5LR to investigate the role of forcings and feedbacks.


"What are the important regional heterogeneities (east-to-west and north-to-south temperature seesaws) in the Europe/Mediterranean sea surface temperature evolution over the past 2k?" - Provide a comprehensive and synthetic view of regional climatic and environmental responses to global or hemispherical changes by using the following tools: O2k phase 1 and 2 records; atmospheric modes to describe the east-to-west and north-to-south temperature seesaws observed in the Mediterranean paleoarchive (e.g. the North Atlantic Oscillation (NAO), East Atlantic pattern (EA), East Atlantic/West Russian pattern (EA/WR)); changes in deep water formation areas (Gulf of Lions, Adriatic and Aegean Sea) characterized with a regional ocean hindcast obtained from a simulation of the NEMO model and PMIP3/CMIP5 simulations driven with realistic natural and anthropogenic forcings, taking advantage of the modelling community contribution to O2k.


Climate Modelling Community input PAST2k-PMIP, VolMIP

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Additional ongoing and planned trans-regional studies relevant to Ocean2k available: Click here



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