Characteristics of Ocean Surface Winds in the Lee of an Isolated Island Observed by Synthetic Aperture Radar

Osamu Isoguchi Earth Observation Research Center, Japan Aerospace Exploration Agency (JAXA), Tsukuba, Ibaraki, Japan

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Masanobu Shimada Earth Observation Research Center, Japan Aerospace Exploration Agency (JAXA), Tsukuba, Ibaraki, Japan

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Hiroshi Kawamura Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai, Miyagi, Japan

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Abstract

Characteristics of ocean surface winds around an isolated island are examined in relation to atmospheric stability using a synthetic aperture radar (SAR) and rawinsonde sounding observations. The SAR-derived winds on 22 May 2009 indicate a low-level jet extending over 30 km behind the island. Around the time of SAR acquisition, winds intensified on the leeward side in association with the stabilization of stratified flows, which suggests the connection of the SAR-derived jet with downslope winds. A number of SAR-derived winds elucidate typical wind patterns and their transitions depending on the nondimensional mountain height . For cases of large (>2), a wake is formed in the lee of the island and low-level jets produce strong wind shear on both sides of the wake. For cases of relatively small (<1.75), although a weak wind region is formed behind the mountain, no wind jets develop. As a transition of the above two cases , a low-level jet develops in the lee of the island, as in the case on 22 May 2009. These wake configurations and their -dependent transitions seem to correspond to major regimes for hydrostatic flow over topography with constant upstream speed and buoyancy frequency: small-amplitude waves , wave breaking , and flow splitting . It is noted that the ocean surface winds behind the island are very sensitive to around the transition point, changing up and down. The occurrence of each wind pattern shows clear seasonal features dependent on atmospheric stability.

Corresponding author address: Osamu Isoguchi, Earth Observation Research Center, Japan Aerospace Exploration Agency (JAXA), 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan. E-mail: isoguchi_osamu@restec.or.jp

Abstract

Characteristics of ocean surface winds around an isolated island are examined in relation to atmospheric stability using a synthetic aperture radar (SAR) and rawinsonde sounding observations. The SAR-derived winds on 22 May 2009 indicate a low-level jet extending over 30 km behind the island. Around the time of SAR acquisition, winds intensified on the leeward side in association with the stabilization of stratified flows, which suggests the connection of the SAR-derived jet with downslope winds. A number of SAR-derived winds elucidate typical wind patterns and their transitions depending on the nondimensional mountain height . For cases of large (>2), a wake is formed in the lee of the island and low-level jets produce strong wind shear on both sides of the wake. For cases of relatively small (<1.75), although a weak wind region is formed behind the mountain, no wind jets develop. As a transition of the above two cases , a low-level jet develops in the lee of the island, as in the case on 22 May 2009. These wake configurations and their -dependent transitions seem to correspond to major regimes for hydrostatic flow over topography with constant upstream speed and buoyancy frequency: small-amplitude waves , wave breaking , and flow splitting . It is noted that the ocean surface winds behind the island are very sensitive to around the transition point, changing up and down. The occurrence of each wind pattern shows clear seasonal features dependent on atmospheric stability.

Corresponding author address: Osamu Isoguchi, Earth Observation Research Center, Japan Aerospace Exploration Agency (JAXA), 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan. E-mail: isoguchi_osamu@restec.or.jp
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  • Alpers, W., U. Pahl, and G. Gross, 1998: Wind fields in coastal areas studied by ERS-1 synthetic aperture radar imagery and numerical modeling. J. Geophys. Res., 103, 78757886.

    • Search Google Scholar
    • Export Citation
  • Alpers, W., A. Ivanov, and J. Horstmann, 2009: Observations of bora events over the Adriatic Sea and Black Sea by spaceborne Synthetic Aperture Radar. Mon. Wea. Rev., 137, 11501161.

    • Search Google Scholar
    • Export Citation
  • Arakawa, S., 2004: Local Winds (in Japanese). Senzando Press, 157 pp.

  • Bauer, M. H., G. J. Mayr, I. Vergeiner, and H. Pichler, 2000: Strongly nonlinear flow over and around a three-dimensional mountain as a function of the horizontal aspect ratio. J. Atmos. Sci., 57, 39713991.

    • Search Google Scholar
    • Export Citation
  • Brighton, P. W. M., 1978: Strongly stratified flow past three-dimensional obstacles. Quart. J. Roy. Meteor. Soc., 104, 289307.

  • Colle, B. A., K. A. Loescher, G. S. Young, and N. S. Winstead, 2006: Climatology of barrier jets along the Alaskan coast. Part II: Large-scale and sounding composites. Mon. Wea. Rev., 134, 454477.

    • Search Google Scholar
    • Export Citation
  • Drazin, P. G., 1961: On the steady flow of a fluid of variable density past an obstacle. Tellus, 8, 239251.

  • Durran, D. R., 2003: Downslope winds. Encyclopedia of the Atmospheric Sciences, J. Holton, J. Pyle, and J. Curry, Eds., Cambridge University Press, 644–650.

    • Search Google Scholar
    • Export Citation
  • Durran, D. R., and J. P. Klemp, 1987: Another look at downslope winds. Part II: Nonlinear amplitude beneath wave-overturning layers. J. Atmos. Sci., 44, 34023412.

    • Search Google Scholar
    • Export Citation
  • Epifanio, C. C., 2003: Lee vortices. Encyclopedia of the Atmospheric Sciences, J. Holton, J. Pyle, and J. Curry, Eds., Cambridge University Press, 1150–1160.

    • Search Google Scholar
    • Export Citation
  • Epifanio, C. C., and R. Rotunno, 2005: The dynamics of orographic wake formation in flows with upstream blocking. J. Atmos. Sci., 62, 31273150.

    • Search Google Scholar
    • Export Citation
  • Etling, D., 1990: Mesoscale vortex shedding from large islands: A comparison with laboratory experiments of rotating stratified flows. Meteor. Atmos. Phys., 43, 145151.

    • Search Google Scholar
    • Export Citation
  • Ferber, G. K., and C. F. Mass, 1990: Surface pressure perturbations produced by an isolated mesoscale topographic barrier. Part II: Influence on regional circulation. Mon. Wea. Rev., 118, 25972606.

    • Search Google Scholar
    • Export Citation
  • Fujita, Y., and H. Onoda, 1984: South-westerly strong winds on the lee side of Rishiri Island (in Japanese with an English abstract). J. Atmos. Res., 36, 121129.

    • Search Google Scholar
    • Export Citation
  • Horstmann, J., W. Koch, S. Lehner, and R. Tonboe, 2000: Wind retrieval over the ocean using synthetic aperture radar with C-band HH polarization. IEEE Trans. Geosci. Remote Sens., 38, 21222131.

    • Search Google Scholar
    • Export Citation
  • Hunt, J. C. R., and W. H. Snyder, 1980: Experiments on stably and neutrally stratified flow over a model three-dimensional hill. J. Fluid Mech., 96, 671704.

    • Search Google Scholar
    • Export Citation
  • Isoguchi, O., and H. Kawamura, 2007: Coastal wind jets flowing into Tsushima Strait and their effect on wind-wave development. J. Atmos. Sci., 64, 564578.

    • Search Google Scholar
    • Export Citation
  • Isoguchi, O., and M. Shimada, 2009: An L-band ocean geophysical model function derived from PALSAR. IEEE Trans. Geosci. Remote Sens., 47, 19251936.

    • Search Google Scholar
    • Export Citation
  • Kawai, Y., H. Kawamura, S. Takahashi, K. Hosoda, H. Murakami, M. Kachi, and L. Guan, 2006: Satellite-based high-resolution global optimum interpolation sea surface temperature data. J. Geophys. Res., 111, C06016, doi:10.1029/2005JC003313.

    • Search Google Scholar
    • Export Citation
  • Laprise, R., and W. R. Peltier, 1989: On the structural characteristics of steady finite-amplitude mountain waves over the bell-shaped topography. J. Atmos. Sci., 46, 586595.

    • Search Google Scholar
    • Export Citation
  • Lilly, D. K., and J. B. Klemp, 1979: The effects of terrain shape on nonlinear hydrostatic mountain waves. J. Fluid Mech., 96, 671704.

    • Search Google Scholar
    • Export Citation
  • Loescher, K. A., G. S. Young, B. A. Colle, and N. S. Winstead, 2006: Climatology of barrier jets along the Alaskan coast. Part I: Spatial and temporal distributions. Mon. Wea. Rev., 134, 437453.

    • Search Google Scholar
    • Export Citation
  • Long, R. R., 1953: Some aspects of the flow of stratified fluids, 1. A theoretical investigation. Tellus, 5, 4258.

  • Mass, C. F., and G. K. Ferber, 1990: Surface pressure perturbations produced by an isolated mesoscale topographic barrier. Part I: General characteristics and dynamics. Mon. Wea. Rev., 118, 25792596.

    • Search Google Scholar
    • Export Citation
  • Miranda, P. M. A., and M. A. Valente, 1997: Critical level resonance in three-dimensional flow past isolated mountains. J. Atmos. Sci., 54, 15741588.

    • Search Google Scholar
    • Export Citation
  • Mitnik, L. M., 1992: Mesoscale coherent structures in the surface wind field during cold air out breaks over the Far Eastern seas from satellite side looking radar. Mer (Paris), 30, 287296.

    • Search Google Scholar
    • Export Citation
  • Monaldo, F. M., D. R. Thompson, R. C. Beal, W. G. Pichel, and P. Clemente-Colón, 2001: Comparison of SAR-derived wind speed with model predictions and ocean buoy measurements. IEEE Trans. Geosci. Remote Sens., 39, 25872600.

    • Search Google Scholar
    • Export Citation
  • Monaldo, F. M., D. R. Thompson, W. G. Pichel, and P. Clemente-Colón, 2004: A systematic comparison of QuikSCAT and SAR ocean surface wind speeds. IEEE Trans. Geosci. Remote Sens., 42, 283291.

    • Search Google Scholar
    • Export Citation
  • Pan, F., and R. B. Smith, 1999: Gap winds and wakes: SAR observations and numerical simulations. J. Atmos. Sci., 56, 905923.

  • Reinecke, P. A., and D. R. Durran, 2008: Estimating topographic blocking using a Froude number when the static stability is nonuniform. J. Atmos. Sci., 65, 10351048.

    • Search Google Scholar
    • Export Citation
  • Sandvik, A. D., and B. R. Furevik, 2002: Case study of a coastal jet at Spitsbergen—Comparison of SAR- and model-estimated wind. Mon. Wea. Rev., 130, 10401051.

    • Search Google Scholar
    • Export Citation
  • Schär, C., and R. B. Smith, 1993a: Shallow-water flow past isolated topography. Part I: Vorticity production and wake formation. J. Atmos. Sci., 50, 13731400.

    • Search Google Scholar
    • Export Citation
  • Schär, C., and R. B. Smith, 1993b: Shallow-water flow past isolated topography. Part II: Transition to vortex shedding. J. Atmos. Sci., 50, 14011412.

    • Search Google Scholar
    • Export Citation
  • Schär, C., and D. R. Durran, 1997: Vortex formation and vortex shedding in continuously stratified flows past isolated topography. J. Atmos. Sci., 54, 534554.

    • Search Google Scholar
    • Export Citation
  • Shimada, M., 1999: Verification processor for SAR calibration and interferometry. Adv. Space Res., 23, 14771486.

  • Shimada, M., 2002: User’s guide to NASDA’s SAR products version 3. NDX-000291, 27 pp.

  • Shimada, M., O. Isoguchi, T. Tadono, and K. Isono, 2009: PALSAR radiometric and geometric calibration. IEEE Trans. Geosci. Remote Sens., 47, 39153932.

    • Search Google Scholar
    • Export Citation
  • Shimada, T., and H. Kawamura, 2004: Wind jets and wind waves off the Pacific coast of northern Japan under winter monsoon captured by combined use of scatterometer, synthetic aperture radar, and altimeter. J. Geophys. Res., 109, C12027, doi:10.1029/2004JC002450.

    • Search Google Scholar
    • Export Citation
  • Shimada, T., and H. Kawamura, 2006: Wind-wave development under alternating wind jets and wakes induced by orographic effects. Geophys. Res. Lett., 33, L02602, doi:10.1029/2005GL025241.

    • Search Google Scholar
    • Export Citation
  • Shimada, T., H. Kawamura, and M. Shimada, 2003: An L-band geophysical model function for SAR wind retrieval using JERS-1 SAR. IEEE Trans. Geosci. Remote Sens., 41, 518531.

    • Search Google Scholar
    • Export Citation
  • Shimada, T., O. Isoguchi, and H. Kawamura, 2008: Numerical simulations of wind wave growth under a coastal wind jet through the Kanmon Strait. Wea. Forecasting, 23, 11621175.

    • Search Google Scholar
    • Export Citation
  • Smith, R. B., 1980: Linear theory of stratified hydrostatic flow past an isolated mountain. Tellus, 32, 348364.

  • Smith, R. B., 1985: On severe downslope winds. J. Atmos. Sci., 42, 25972603.

  • Smith, R. B., and V. Grubišić, 1993: Aerial observations of Hawaii’s wake. J. Atmos. Sci., 50, 37283750.

  • Smith, R. B., A. C. Gleason, P. A. Gluhosky, and V. Grubišić, 1997: The wake of St. Vincent. J. Atmos. Sci., 54, 606623.

  • Smolarkiewicz, P. K., and R. Rotunno, 1989: Low Froude number flow past three-dimensional obstacles. Part I: Baroclinically generated lee vortices. J. Atmos. Sci., 46, 11541164.

    • Search Google Scholar
    • Export Citation
  • Stoffelen, A., and D. Anderson, 1997: Scatterometer data interpretation: Estimation and validation of the transfer function CMOD4. J. Geophys. Res., 102, 57675780.

    • Search Google Scholar
    • Export Citation
  • Takai, H., H. Kawamura, and O. Isoguchi, 2006: Characteristics of the yamase winds over the oceans around Japan observed by the scatterometer-derived ocean surface winds. J. Meteor. Soc. Japan, 84, 365373.

    • Search Google Scholar
    • Export Citation
  • Thorsteinsson, S., 1988: Finite amplitude stratified air flow past isolated mountains on an f-plane. Tellus, 40A, 220236.

  • Walter, B. A., and J. E. Overland, 1982: Response of stratified flow in the lee of the Olympic Mountains. Mon. Wea. Rev., 110, 14581473.

    • Search Google Scholar
    • Export Citation
  • Winstead, N. S., and Coauthors, 2006: Using SAR remote sensing, field observations, and models to better understand coastal flows in the Gulf of Alaska. Bull. Amer. Meteor. Soc., 87, 787800.

    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., W. T. Liu, Q. Liu, and M. Nonaka, 2001: Far-reaching effects of the Hawaiian Islands on the Pacific ocean–atmosphere system. Science, 292, 20572060.

    • Search Google Scholar
    • Export Citation
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