# Trouet et al. 2009 NAO Reconstruction #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 4.0 # Encoding: UTF-8 # NOTE: Please cite original publication, NOAA Landing Page URL, dataset and publication DOIs (where available), # and date accessed when using these downloaded data. If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed. # # NOAA_Landing_Page: https://www.ncei.noaa.gov/access/paleo-search/study/8713 # Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata. # # Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-recon-8713.json # Study_Level_JSON_Description: JSON metadata of this file's parent study, which includes all study metadata. # # Data_Type: Climate Reconstructions # # Dataset_DOI: # # Science_Keywords: Atmospheric and Oceanic Circulation Patterns Reconstruction #------------------- # Resource_Links # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/treering/reconstructions/nao-trouet2009-noaa.txt # Data_Download_Description: NOAA Template File; North Atlantic Oscillation Data # # Original_Source_URL: # Original_Source_Description: # #------------------- # Contribution_Date # Date: 2009-04-01 #------------------- # File_Last_Modified_Date # Date: 2022-03-30 #------------------- # Title # Study_Name: Trouet et al. 2009 NAO Reconstruction #------------------- # Investigators # Investigators: Trouet, V.; Esper, J.; Graham, N.E.; Baker, A.; Scourse, J.D.; Frank, D.C. #------------------- # Description_Notes_and_Keywords # Description: Winter NAO Reconstruction 1049-1995 AD. Decadal scale variations in a speleothem-based precipitation proxy from Scotland and a tree-ring based drought proxy from Morocco reflect quasi-regular occurrences of contrasting precipitation regimes over the Millennium. These proxy records are located centrally in the opposing poles of North Atlantic Oscillation (NAO) driven precipitation regimes. Analogous to the instrumental based NAO index, we combined both records to develop a near millennium-long (1049-1995) record of winter NAO (wNAO). A 30-year smoothing spline was applied to both proxy series and they were normalized over the common period before their residual was calculated. Extreme phases in the difference record (Scotland minus Morocco) corresponded to typical wNAO related geopotential height and precipitation patterns over Europe over the last three centuries. Low frequency NAO phases over the 20th century are well captured in the proxy record, which correlates reasonably well with instrumental wNAO index time series. On longer time-scales, the multidecadal variations in our wNAO reconstruction are similar to the ones found in previous NAO reconstructions. Our wNAO record, however, is 350 years longer than the currently longest reconstructions and extends into the Medieval Climate Anomaly (MCA), for which a persistent positive mode is reconstructed. #------------------- # Publication # Authors: Trouet, V., J. Esper, N.E. Graham, A. Baker, J.D. Scourse, and D.C. Frank # Journal_Name: Science # Published_Title: Persistent Positive North Atlantic Oscillation Mode Dominated the Medieval Climate Anomaly. # Published_Date_or_Year: 2009-04-03 # Volume: 324 # Issue: # Pages: 78-80 # Report_Number: # DOI: 10.1126/science.1166349 # Full_Citation: # Abstract: The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker NAO conditions into the Little Ice Age (LIA). Globally distributed proxy data suggest that this NAO shift is one aspect of a global MCA-LIA climate transition that probably was coupled to prevailing La Nina-like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA. #------------------- # Funding_Agency # Funding_Agency_Name: European Commission MILLENNIUM Integrated Project # Grant_Number: 017008 #------------------- # Funding_Agency # Funding_Agency_Name: Swiss National Science Foundation through the National Centre for Competence in Climate Research (NCCR-Climate) # Grant_Number: #------------------- # Funding_Agency # Funding_Agency_Name: National Oceanic and Atmospheric Administration (NOAA) # Grant_Number: NA06OA-R4310120 #------------------- # Funding_Agency # Funding_Agency_Name: Royal Society-Leverhulme Trust # Grant_Number: Senior Research Fellowship #------------------- # Site_Information # Site_Name: North Atlantic Oscillation # Location: North Atlantic Ocean # Northernmost_Latitude: 65 # Southernmost_Latitude: 38 # Easternmost_Longitude: -10 # Westernmost_Longitude: -50 # Elevation_m: #------------------- # Data_Collection # Collection_Name: nao_Trouet2009b # First_Year: 1049 # Last_Year: 1995 # Time_Unit: CE # Core_Length_m: # Parameter_Keywords: reconstructions # Notes: #------------------- # Chronology_Information # Chronology: #------------------- # Variables # # PaST_Thesaurus_Download_Resource: https://www.ncdc.noaa.gov/paleo/skos/past-thesaurus.rdf # PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format. # # Variables format: shortname <tab> what,material,error,units,seasonality,data_type,detail,method, C(har) or N(umeric) data,additional information # ## age age,,,year Common Era,,climate reconstructions;speleothems;tree ring,,,N, ## nao North Atlantic Oscillation Index,,,dimensionless,winter,climate reconstructions;speleothems;tree ring,,,N, # 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