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Ocean Tide Modeling in the Polar Oceans

C.K. Shum(1) , Yu Wang(1) , Yuchan Yi(1) , Shin-chan Han(1) , Koji Matsumoto(2) , Yoshihiro Niwa(3) , and Alexander Braun(4)

(1) Ohio State University, 125 S Oval Mall, Columbus, Ohio 43210, United States
(2) National Astronomical Observatory of Japan, 2-12, Hoshigaoka,, Mizusawa, Iwate 023-0861, Japan
(3) University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, , Tokyo, 113-0033, Japan
(4) University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada

Abstract

Ocean tides play a significant role in climate due to its complex interactions between ocean, atmosphere, solid Earth and sea ice. Tides have strong effects on circulations near coastal regions or on continental shelves [Mofjeld et al. 1995; Han, 2000]. Tidal currents create turbulent mixing [Munk and Wunsch, 1998], tidal dissipation affects oceanic transport and thus climate [Wunsch, 2000; Egbert and Ray, 2000; Ray and Cartwright, 2001] and internal tidal mixing affects general circulation [Jayne and St. Laurent, 2001; St. Laurent and Garett, 2002; Simmons et al., 2003]. Due primarily to the availability of TOPEX/POSEIDON (T/P) satellite altimetry [Chelton et al., 2001] and advances in numerical modeling methodologies [LeProvost et al., 1994; 1995; 1999], semidiurnal and diurnal barotropic ocean tides are known in the deep ocean (depth>1000 m) to within 2 cm rms and with a spatial resolution of 50 km [Shum et al., 1997]. Tides are less well known in the coastal regions, over continental shelves, and in polar oceans [Yi et al., 2003] due primarily to limited observations with adequate spatial resolutions, data outage from T/P (and JASON-1) in seasonally or permanently sea ice covered polar oceans in which the complicated processes due to non-linear hydrodynamics including internal or baroclinic tides [Ray and Mitchum, 1996; Merrifield et al., 2001; Niwa and Hibiya, 2001] are poorly known. Most of the current global ocean tide models are primarily constrained by the FES94 hydrodynamics model [LeProvost et al., 1994] in the polar oceans. This paper provides a study of polar ocean (±50 deg latitude, north and south poleward) barotropic tide modeling using high-latitude observing satellite radar altimetry including T/P, JASON-1, ERS-1/-2, GFO and ENVISAT. Dual-satellite crossovers are used for barotropic empirical tidal solutions with an objective to mitigate tidal aliasing [Yi et al., 2005], and techniques of data assimilations with hydrodynamic modeling [Matsumoto et al., 2000] are used to enable extrapolations into data outage regions. New high-latitude space geodetic sensors, GRACE [Han et al., 2005] and ICESat [Matsumoto et al., 2005], are explored for their contributions to polar tide modeling and accuracy evaluations, in particular, over sea ice and ice shelves.

 

Workshop presentation

 

                 Last modified: 07.10.03