11-Jinyun Guo by nuhman10


									Surface geostrophic velocity from crossover of satellite altimetry
Jinyun Guo1,2, Cheinway Hwang1 and Hsuan-Chang Shih1
    Dept. of Civil Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu

30050, Taiwan, guojy@geodesy.cv.nctu.edu.tw, hwang@geodesy.cv.nctu.edu.tw
    Dept. of Land Information and Surveying Engineering, Xuzhou Normal University, 29

Shanghai Road, Tongshan New District, Xuzhou 221116, Jiangsu, China,


       When the Coriolis force is balanced by the pressure gradient in the hydrostatic

equilibrium, the ocean current is referred to as geostrophic current. Most ocean currents are

approximately geostrophic currents. The geostrophic velocity is calculated from crossover of

satellite altimetry in the paper. The uncertainties of geostrophic velocity are analyzed. If the

accuracy of the sea slope along the ascending or descending track is at the 10-7 level, the

geostrophic velocity can get the accuracy of better than 10cm/s. the Kuroshio area to the east

of Taiwan is selected as a test region. A highly accurate and up-to-date geoidal model is

determined from the ground-based gravimetry, ship-borne gravimetry, air-borne gravimetry

and satellite altimetry. So the more accurate geoidal height can be computed from the model.

The geophysical data records (GDRs) of TOPEX/Poseidon between 2002 and 2005 are used

to get the highly accurate dynamic heights of crossover points. Then the geostrophic

velocities are computed from the crossovers and are basically identical to the current

velocities of NCOR.

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