# Atlantic Meridional Overturning Circulation (AMOC) Reconstruction from 10,000 to 2,000 BP #----------------------------------------------------------------------- # 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 downloaded data. # If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed. # # Description/Documentation lines begin with '#' followed by a space # Data lines have no '#' # # NOAA_Landing_Page: https://www.ncdc.noaa.gov/access/paleo-search/study/35153 # 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-35153.json # Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata. # # Data_Type: Climate Reconstructions # # Dataset_DOI: # # Science_Keywords: #--------------------------------------- # Resource_Links # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/reconstructions/vincent2022/amoc_recon_vincent2022.txt # Data_Download_Description: NOAA Template File; AMOC Reconstruction Data # #--------------------------------------- # Contribution_Date # Date: 2022-03-03 #--------------------------------------- # File_Last_Modified_Date # Date: 2022-03-03 #--------------------------------------- # Title # Study_Name: Atlantic Meridional Overturning Circulation (AMOC) Reconstruction from 10,000 to 2,000 BP #--------------------------------------- # Investigators # Investigators: Swingedouw, Didier; Jomelli, Vincent #--------------------------------------- # Description_Notes_and_Keywords # Description: This AMOC reconstruction is based on the Ayache et al. (2018) reconstruction of the AMOC. This reconstruction was based on 22 proxy records of SST in the North Atlantic. The reconstruction was obtained from a Principal Component Analysis of those 22 proxy records. The reconstruction of the AMOC has been tested and validated using pseudo-proxy approach, consisting in testing the performance of the statistical method to reconstruct the AMOC from model simulations using the location of available proxy data. The AMOC reconstruction was also compared with other independent proxy records of the deep ocean circulation and show consistency. The reconstruction has a time resolution of 50 years and cover the period -10-2kY. For further details on the reconstruction method, see: Ayache M. Swingedouw D., Mary Y., Eynaud F., Colin C. (2018) AMOC variability over the Holocene: A new reconstruction based on multiple proxy-based SST records. Global and Planetary Changes 170, pp. 172-189. This first reconstruction from the latter paper was not calibrated in terms of Sverdrups of variation of the AMOC but standardised on the available period. To circumvent this issue, the reconstruction proposed here has been calibrated using Northern Hemisphere reconstruction of Kaufman et al. (2020) and transient model simulations as well as hosing simulations, in order to quantify the climatic impacts of AMOC variations. For further details on the method, please refer to the publication described below: #--------------------------------------- # Publication # Authors: Jomelli V., and Swingedouw D. # Published_Date_or_Year: # Published_Title: AMOC control on millennial-scale glacier changes during the Holocene # Journal_Name: Nature Communications # Volume: # Edition: # Issue: # Pages: # Report_Number: # DOI: # Online_Resource: # Full_Citation: # Abstract: #--------------------------------------- # Publication # Authors: Ayache M., Swingedouw D., Mary Y., Eynaud F., Colin, C. # Published_Date_or_Year: 2018 # Published_Title: AMOC variability over the Holocene: A new reconstruction based on multiple proxy-based SST records # Journal_Name: Global and Planetary Change # Volume: 170 # Edition: # Issue: # Pages: 48-61 # Report_Number: # DOI: 10.1016/j.gloplacha.2018.08.016 # Online_Resource: # Full_Citation: # Abstract: The Meridional Overturning Circulation (AMOC) is believed to have played a key role in climate variability over the Holocene, but the reconstruction of its variations remains limited by inconsistencies among different proxy records used. To circumvent this issue, we propose a new statistical method to reconstruct the AMOC variations based on multiple sources of information, i.e. 22 proxy records of annual Sea Surface Temperature (SST) compiled in the North Atlantic and covering the Holocene (HAMOC database). Our approach consists of isolating the main variability modes hidden in the Atlantic Ocean through principal component analysis (PCA) and then evaluating their link with the AMOC. To estimate the skill of our method, we use a pseudo-proxy approach applied to observational SST data covering the period 1870–2010, as well as simulations from a comprehensive climate model (IPSL-CM5A-LR) where the AMOC variations are known. In instrumental observations and most of the model simulations, the first mode of SST variations from the PCA analysis over the North Atlantic can be related with the external radiative forcing, while the second mode is reminiscent of the AMOC variability and of its signature on SST. When computed over the Holocene period using the HAMOC database, the first mode is indeed well correlated with the insolation changes, marked by a general cooling of the Northern Atlantic from 9 thousand years ago (ka). The second mode, that we consider here as a reconstruction of standardized AMOC variations following the pseudo-proxy analysis in the model simulations and in the observations, is in general agreement with a few independent reconstructions of the deep branch of the AMOC recorded in the North Atlantic. Based on this new AMOC index reconstruction, we highlight that the Early Holocene may have been associated with an AMOC enhancement, followed by a general weakening trend from around 6–7 ka up to 2 ka, in line with the major hydro-dynamical re-organization which occurred in the North Atlantic from the mid-Holocene period. We find that the late Holocene period is marked by two fluctuations, with maxima at about 4.2 and 5 ka, in line with short-term variations identified in proxy records of the velocity of the Greenland-Iceland-Scotland overflow waters. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: ANR France # Grant: ANR-13- BS06-0003 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Belmont Forum # Grant: PACMEDY #--------------------------------------- # Site_Information # Site_Name: 22 Cores in North Atlantic Ocean # Location: North Atlantic Ocean # Northernmost_Latitude: 80 # Southernmost_Latitude: 10 # Easternmost_Longitude: 20 # Westernmost_Longitude: -80 # Elevation_m: #--------------------------------------- # Data_Collection # Collection_Name: amoc_recon_vincent2022 # First_Year: 10000 # Last_Year: 2000 # Time_Unit: calendar year before present # Core_Length_m: # Parameter_Keywords: reconstruction # Notes: #--------------------------------------- # Chronology_Information # Chronology: #--------------------------------------- # Variables # PaST_Thesaurus_Download_Resource: https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf # PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format. # # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data) # ## Year_BP age,,,calendar year before present,annual,paleoceanography ,interpolated,,N,statisitical reconstruction; Interpolation using 22 proxy records of HAMOC database to perform principal component analysis; Principal Component Analysis using various proxy data interpolated using a 50 years time bin ## AMOC Atlantic Meridional Overturning Circulation Index,multiple proxies,,Sverdrup,annual,climate reconstructions; paleoceanography ,,Principal component analysis,N, statisitical reconstruction calibrated using climate simulations; Reconstruction performed in Ayache et al. (2018) Calibration done in Jomelli et al. (2022); Reconstruction based Principal component analysis of 22 proxy records of SST in the North Atlantic and calilbration using climate models; #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: NA Year_BP AMOC 2000 -2.236 2050 -2.335 2100 -2.450 2150 -2.504 2200 -2.484 2250 -2.325 2300 -2.069 2350 -1.649 2400 -1.223 2450 -1.203 2500 -1.437 2550 -1.444 2600 -1.206 2650 -1.020 2700 -0.955 2750 -0.965 2800 -1.120 2850 -1.195 2900 -0.896 2950 -0.586 3000 -0.608 3050 -0.754 3100 -0.876 3150 -0.952 3200 -0.905 3250 -0.771 3300 -0.578 3350 -0.317 3400 -0.137 3450 -0.235 3500 -0.532 3550 -0.683 3600 -0.595 3650 -0.478 3700 -0.376 3750 -0.207 3800 0.050 3850 0.376 3900 0.511 3950 0.223 4000 -0.120 4050 -0.032 4100 0.383 4150 0.935 4200 1.554 4250 1.810 4300 1.411 4350 0.842 4400 0.621 4450 0.570 4500 0.415 4550 0.197 4600 0.063 4650 0.118 4700 0.424 4750 0.852 4800 1.112 4850 1.182 4900 1.189 4950 1.273 5000 1.401 5050 1.273 5100 0.840 5150 0.521 5200 0.642 5250 0.852 5300 0.759 5350 0.592 5400 0.470 5450 0.407 5500 0.570 5550 0.593 5600 0.365 5650 0.205 5700 0.108 5750 0.059 5800 0.021 5850 -0.035 5900 0.036 5950 0.274 6000 0.639 6050 1.080 6100 1.306 6150 1.222 6200 1.012 6250 0.859 6300 0.958 6350 1.317 6400 1.711 6450 1.869 6500 1.773 6550 1.674 6600 1.767 6650 1.953 6700 2.004 6750 1.934 6800 1.764 6850 1.513 6900 1.555 6950 1.881 7000 1.975 7050 1.784 7100 1.511 7150 1.181 7200 1.013 7250 1.166 7300 1.286 7350 1.209 7400 1.094 7450 1.076 7500 1.207 7550 1.253 7600 1.165 7650 0.980 7700 0.799 7750 0.806 7800 0.637 7850 0.269 7900 0.246 7950 0.387 8000 0.159 8050 -0.120 8100 -0.020 8150 0.364 8200 0.576 8250 0.475 8300 0.529 8350 0.603 8400 0.388 8450 0.090 8500 -0.069 8550 -0.184 8600 -0.238 8650 -0.116 8700 -0.203 8750 -0.514 8800 -0.702 8850 -0.800 8900 -0.907 8950 -1.234 9000 -1.625 9050 -1.529 9100 -1.290 9150 -1.433 9200 -1.646 9250 -1.648 9300 -1.570 9350 -1.672 9400 -1.817 9450 -1.787 9500 -1.806 9550 -1.755 9600 -1.673 9650 -1.813 9700 -1.833 9750 -1.525 9800 -1.323 9850 -1.595 9900 -1.897 9950 -1.769 10000 -1.515