edu.ucar.opensky::articles:24117 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:06:35.050376 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7nc64jx Impact of coherent ocean stratification on AMOC reconstruction by coupled data assimilation with a biased model 2020-07-01T00:00:00Z publication https://n2t.org/ark:/85065/d7nc64jx https://doi.org/10.1175/JCLI-D-19-0735.1 Lu, L. author Zhang, S. author Yeager, Stephen author Danabasoglu, Gokhan author Chang, P. author Wu, L. author Lin, X. author Rosati, A. author Lu, F. author UCAR/NCAR - Library publisher The Atlantic meridional overturning circulation (AMOC) is of great importance in Earth's climate system, and reconstructing its structure and variability by combining observations with a coupled model is a key step in understanding historical and future states of AMOC. However, models always have systematic errors called bias owing to imperfect numerical representation of the real world. Model bias and the sparse nature of ocean observations, particularly in deep oceans, make it difficult to generate a complete historical picture of AMOC structure and variability. Here, two coupled models that are biased with respect to each other are used to design "twin'' experiments to systematically study the influence of model bias on AMOC reconstruction. One model is used to produce the "observations'' that sample the "true'' solution of the AMOC to be reconstructed, while the other model is used to incorporate the "observations'' to reconstruct the "truth'' through coupled data assimilation (CDA). The degree to which the "truth'' is recovered by a CDA scheme assesses the critical role of coherent (both upper- and deep-ocean incorporate enough observations to mitigate stratification instability) ocean stratification on AMOC reconstruction. Results show that balancing restoration of climatology and assimilation of observations is vital to better reconstruct AMOC structure and variability, given that most ocean observations are only available in the upper 2000 m. The gained results serve as a guideline in ocean-state estimation with a balance of deep restoring and upper data constraint for climate prediction initialization, especially for decadal predictions. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2020 American Meteorological Society (AMS). None eng geoscientificInformation