# Multiproxy El Nino-Southern Oscillation 1,000 Year Reconstructions #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/25891 # Description: NOAA Landing Page # Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/datwyler2019/readme-datwyler2019.txt # Description: NOAA location of the template # # Original_Source_URL: # Description: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Climate Reconstructions # # Dataset DOI: # # Parameter_Keywords: atmospheric circulation #-------------------- # Contribution_Date # Date: 2019-03-11 #-------------------- # File_Last_Modified_Date # Date: 2019-03-11 #-------------------- # Title # Study_Name: Multiproxy El Nino-Southern Oscillation 1,000 Year Reconstructions #-------------------- # Investigators # Investigators: Dätwyler, C.; Abram, N.J.; Grosjean, M.; Wahl, E.R.; Neukom, R. #-------------------- # Description_Notes_and_Keywords # Description: Multiproxy El Nino-Southern Oscillation (ENSO) reconstructions for the past 1,000 years, expressed as first principal component, plus underlying proxy data and references. # Files are as follows: # Reconstructions: # # The data files of our final reconstructions are organised as follows: # 1st column: Final reconstruction # 2nd column: Target ENSO index # 3rd column: Final reconstruction # 4th column: Upper confidence interval of the final reconstruction # 5th column: Lower confidence interval of the final reconstruction # 6th column: 31-year filtered final reconstruction # 7th column: Upper confidence interval of the 31-year filtered final reconstruction # 8th column: Lower confidence interval of the 31-year filtered final reconstruction # # RunningPC1.txt # Final Running PC1 ENSO reconstruction, obtained by patching together all five reconstructions (Running PC1 1000, 1400, 1600, 1800 and 1854) in respective temporal order (for each year we use the data of the most replicated available subset). Before patching together, the five reconstructions were scaled to the variance and mean of the target ENSO index over the reference period 1930-1990. # # FullPeriodPC1.txt # Final Full Period PC1 ENSO reconstruction, obtained by patching together all five reconstructions (Full Period PC1 1000, 1400, 1600, 1800 and 1854) in respective temporal order (for each year we use the data of the most replicated available subset). Before patching together, the five reconstructions were scaled to the variance and mean of the target ENSO index over the reference period 1930-1990. # # OverlapPeriodPC1.txt # Final Overlap Period PC1 ENSO reconstruction, obtained by patching together all five reconstructions (Overlap Period PC1 1000, 1400, 1600, 1800 and 1854) in respective temporal order (for each year we use the data of the most replicated available subset). Before patching together, the five reconstructions were scaled to the variance and mean of the target ENSO index over the reference period 1930-1990. # # Proxy data: # # ProxyRecords.txt # Data of the proxy records, infilled to have no missing values as explained in Sections 2.1 and 2.2. This corresponds to the collection of the most replicated subset (1854 subset), i.e. records # - with a data gap no longer than 30 years in the reference period 1930-1990 # - correlating significantly (p < 0.05) with ENSO over the 1930-1990 reference period # - with no more than 20% missing values over 1854-1990 # (see Sections 2.1 and 2.2 in the article) # # MetadataProxyRecords.txt # Meta data of the proxy records in "ProxyRecords.txt" # #-------------------- # Publication # Authors: Christoph Dätwyler, Nerilie J. Abram, Martin Grosjean, Eugene R. Wahl, Raphael Neukom # Published_Date_or_Year: 2019-01-09 # Published_Title: El Nino-Southern Oscillation variability, teleconnection changes and responses to large volcanic eruptions since AD 1000 # Journal_Name: International Journal of Climatology # Volume: # Edition: # Issue: # Pages: # Report_Number: # DOI: 10.1002/joc.5983 # Online_Resource: https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/joc.5983 # Full_Citation: # Abstract: The El Nino-Southern Oscillation (ENSO) is the earth's dominant mode of inter-annual climate variability. It alternates between warm (El Nino) and cold (La Nina) states, with global impacts on climate and society. This study provides new ENSO reconstructions based on a large, updated collection of proxy records. We use a novel reconstruction approach that employs running principal components, which allows us to take covariance changes between proxy records into account and thereby identify periods of likely teleconnection changes. Using different implementations of the principal component analysis enables us to identify periods within the last millennium when quantifications of ENSO are most robust. These periods range from 1580 to the end of the 17th century and from 1825 to present. We incorporate an assessment of consistency among our new and existing ENSO reconstructions leading to five short phases of low agreement among the reconstructions between 1700 and 1786. We find a consistent spatial pattern of proxy covariance during these four phases, differing from the structure seen over the instrumental period. This pattern points towards changes in teleconnections in the west Pacific/Australasian region, compared to the present state. Using our new reconstructions, we find a significant response of ENSO towards more La Nina-like conditions 3-5 years after major volcanic events. We further show that our new reconstructions and existing reconstructions largely agree on the state of ENSO during volcanic eruptions in the years 1695 and 1784, which helps put into perspective the climatic response to these events. During all other large volcanic eruptions of the last 1000 years, there is no reconstruction coherency with regard to the state of ENSO. #------------------ # Funding_Agency # Funding_Agency_Name: Swiss National Science Foundation # Grant: Ambizione PZ00P2_154802 #------------------ # Site_Information # Site_Name: Global # Location: Geographic Region>Global # Country: # Northernmost_Latitude: 90 # Southernmost_Latitude: -90 # Easternmost_Longitude: 180 # Westernmost_Longitude: -180 # Elevation: #------------------ # Data_Collection # Collection_Name: Datwyler2019ENSO # Earliest_Year: 1000 # Most_Recent_Year: 2014 # Time_Unit: CE # Core_Length: # Notes: #------------------ # Chronology_Information # Chronology: # #---------------- # Variables # # Data variables follow are preceded by "##" in columns one and two. # Data line variables format: one per line, shortname-tab-variable components (what, material, error, units, seasonality, data type,detail, method, C or N for Character or Numeric data, free text) # ## age_CE age, , , Common Era, , , , ,N, ## PC1 ENSO First Principal Component, , , , ,climate reconstructions,,,N, # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # age_CE PC1