Investigation of the summer Kara Sea circulation employing a variational data assimilation technique
Nechaev, D. A.
MetadataShow full item record
The summer circulations and hydrographic fields of the Kara Sea are reconstructed for mean, positive and negative Arctic Oscillation regimes employing a variational data assimilation technique which provides the best fit of reconstructed fields to climatological data and satisfies dynamical and kinematic constraints of a quasi-stationary primitive equation ocean circulation model. The reconstructed circulations agree well with the measurements and are characterized by inflow of 0.63, 0.8, 0.51 Sv through Kara Gate and 1.18, 1.1, 1.12 Sv between Novaya Zemlya and Franz Josef Land, for mean climatologic conditions, positive and negative AO indexes, respectively. The major regions of water outflow for these regimes are the St. Anna Trough (1.17, 1.21, 1.34 Sv) and Vilkitsky/Shokalsky Straits (0.52, 0.7, 0.51 Sv). The optimized velocity pattern for the mean climatological summer reveals a strong anticyclonic circulation in the central part of the Kara Sea (Region of Fresh Water Inflow, ROFI zone) and is confirmed by ADCP surveys and laboratory modeling. This circulation is well pronounced for both high and low AO phases, but in the positive AO phase it is shifted approximately 200 km west relatively to its climatological center. During the negative AO phase the ROFI locaion is close to its climatological position. The results of the variational data assimilation approach were compared with the simulated data from the Hamburg Shelf Ocean Model (HAMSOM) and Naval Postgraduate School 18 km resolution (NPS-18) model to validate these models.
Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): C04S15, doi:10.1029/2006JC003728.
Showing items related by title, author, creator and subject.
Towards an integrated observation and modeling system in the New York Bight using variational methods. Part I : 4DVAR data assimilation Zhang, Weifeng G.; Wilkin, John L.; Arango, Hernan G. (2009-09-23)Four-dimensional Variational data assimilation (4DVAR) in the Regional Ocean Modeling System (ROMS) is used to produce a best-estimate analysis of ocean circulation in the New York Bight during spring 2006 by assimilating ...
Towards an integrated observation and modeling system in the New York Bight using variational methods. Part II : repressenter-based observing strategy evaluation Zhang, Weifeng G.; Wilkin, John L.; Levin, Julia C. (2009-09-23)As part of an effort to build an integrated observation and modeling system for the New York Bight, this study explores observing system design using a representer-based method. The Representer of a single observation ...
The role of biological production in pleistocene atmospheric carbon dioxide variations and the nitrogen isotope dynamics of the southern ocean Sigman, Daniel M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-09)This dissertation contributes to the search for a cause of glacial/interglacial variations in atmospheric carbon dioxide. The hypotheses addressed involve changes in low and high-latitude biological export production. A ...