Understanding the Atlantic OceanCirculation in the Past 22,000 Years Using an Isotope-enabled Ocean Model
Date:2019/12/27

Reporter: Sifan Gu

Time:2019/12 /30,  8:30-9:30

Location:SOO Room 120

Abstract:

proxy records suggest that Atlantic ocean circulation experienced substantial changes during the past 22,000 years, which played an important role in regulating past climate changes. This period, with abundant paleo observations, provides an excellent opportunity to improve our understanding of the mechanisms underlying ocean circulation and climate change. However, proxy records are not direct measurements of physical variables, and the interpretation of proxy records can be influenced by many processes, complicating the model-data comparison. Therefore, different isotopes are implemented in climate models, which makes direct model-data comparison possible. In this study, an isotope-enabled ocean model (iCESM) is used to investigate Atlantic ocean circulation during the Last Glacial Maximum (LGM) and the last deglaciation as well as to assess the ability of different proxies to reconstruct past ocean condition. From direct model-data comparison, several specific problems are investigated: (1) Deglacial Antarctic Intermediate Water (AAIW) in the Atlantic; (2) Zonal contrast of d18O in the benthic foraminifera and Atlantic Meridional Overturning Circulation (AMOC) strength during the last deglaciation; (3) Atlantic water mass and AMOC during the LGM. These examples suggest that iCESM is a powerful tool for improving our understanding of past ocean changes and interpretations of proxy records.

 

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