Decorrelation scales for Arctic Ocean hydrogpraphy - Part I: Amerasian Basin


Contact
Hiroshi.Sumata [ at ] awi.de

Abstract

Any use of observational data for data assimilation requires adequate information of their representativeness in space and time. This is particularly important for sparse, non-synoptic data, which comprise the bulk of oceanic in situ observations in the Arctic. To quantify spatial and temporal scales of temperature and salinity variations, we estimate the autocorrelation function and associated decorrelation scales for the Amerasian Basin of the Arctic Ocean. For this purpose, we compile historical measurements from 1980 to 2015. Assuming spatial and temporal homogeneity of the decorrelation scale in the basin interior (abyssal plain area), we calculate autocorrelations as a function of spatial distance and temporal lag. The examination of the functional form of autocorrelation in each depth range reveals that the autocorrelation is well described by a Gaussian function in space and time. We derive decorrelation scales of 150–200 km in space and 100–300 days in time. These scales are directly applicable to quantify the representation error, which is essential for use of ocean in situ measurements in data assimilation. We also describe how the estimated autocorrelation function and decorrelation scale should be applied for cost function calculation in a data assimilation system.



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Article
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Primary Division
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Research Networks
Peer revision
ISI/Scopus peer-reviewed
Publication Status
Published
Eprint ID
46680
DOI 10.5194/os-14-161-2018

Cite as
Sumata, H. , Kauker, F. , Karcher, M. , Rabe, B. , Timmermans, M. L. , Behrendt, A. , Gerdes, R. , Schauer, U. , Shimada, K. , Cho, K. H. and Kikuchi, T. (2018): Decorrelation scales for Arctic Ocean hydrogpraphy - Part I: Amerasian Basin , Ocean Science, 14 , pp. 161-185 . doi: 10.5194/os-14-161-2018


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