Computation of wind vectors over the ocean using spaceborne synthetic aperture radar

The high resolution and large coveeage of satellite synthetic aperture radar (SAR) offer a unique opportunity to derive mesoscale wind fields over the ocean surface and to investigate their spatial variation. For this purpose, different algorithms were developed and tested using SAR images from two European Remote Sensing satellites. In this article, the methods for deriving wind fields from SAR data are introduced. The wind directions are extracted from wind-induced streaks visible on most SAR images. Wind speeds are derived from the normalized radar cross section by applying an empirical C-band model. The different sources of error in wind retrieval that must be considered are discussed with respect to Radarsat/ScanSAR data. Furthermore, SAR-retrieved ocean surface winds are used to investigate the spatial variation of winds at different scales.

[1]  H. Charnock.  Wind stress on a water surface , 1955 .

[2]  I. V. D. Hoven.  POWER SPECTRUM OF HORIZONTAL WIND SPEED IN THE FREQUENCY RANGE FROM 0.0007 TO 900 CYCLES PER HOUR , 1957 .

[3]  J. Wright,et al.  Backscattering from capillary waves with application to sea clutter , 1966 .

[4]  J. Wright.  A new model for sea clutter , 1968 .

[5]  R. Kraichnan.  Inertial-range transfer in two- and three-dimensional turbulence , 1971, Journal of Fluid Mechanics.

[6]  J. Kaimal,et al.  Spectral Characteristics of Surface-Layer Turbulence , 1972 .

[7]  C. E. Elderkin,et al.  An Investigation of the Application of Taylor's Hypothesis to Atmospheric Boundary Layer Turbulence. , 1974 .

[8]  G. Valenzuela.  Theories for the interaction of electromagnetic and oceanic waves — A review , 1978 .

[9]  O. Phillips.  Spectral and statistical properties of the equilibrium range in wind-generated gravity waves , 1985, Journal of Fluid Mechanics.

[10]  Michael H. Freilich,et al.  Wavenumber Spectra of Pacific Winds Measured by the Seasat Scatterometer , 1986 .

[11]  P. Snoeij,et al.  The Polarization Dependent Relation Between Radar Backscatter From The Ocean Surface And Surface Wind Vector At Frequencies Between 1 And 18 GHz , 1990, 10th Annual International Symposium on Geoscience and Remote Sensing.

[12]  Paul Snoeij,et al.  The polarization-dependent relation between radar backscatter from the ocean surface and surface wind vector at frequencies between 1 and 18 GHz , 1991, IEEE Trans. Geosci. Remote. Sens..

[13]  H. Kapitza,et al.  The non-hydrostatic mesoscale model GESIMA. I : Dynamical equations and tests , 1992 .

[14]  Y. Quilfen,et al.  Calibration/validation of ERS-1 scatterometer precision products , 1994, Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing Symposium.

[15]  W. Alpers,et al.  Atmospheric boundary layer rolls observed by the synthetic aperture radar aboard the ERS-1 satellite , 1994 .

[16]  Jochen Horstmann,et al.  Wind measurements using ERS-1 SAR , 1995 .

[17]  P. W. Vachon,et al.  Validation of wind vector retrieval from ERS-1 SAR images over the ocean , 1996 .

[18]  I. Robinson,et al.  Demonstration of an improved calibration scheme for ERS-l SAR imagery using a scatterometer wind model , 1996 .

[19]  S. Lehner,et al.  Mesoscale wind measurements using recalibrated ERS SAR images , 1998 .

[20]  Robert A. Shuchman,et al.  Wind vector retrieval using ERS-1 synthetic aperture radar imagery , 1996, IEEE Trans. Geosci. Remote. Sens..

[21]  Henri Laur,et al.  Derivation of the backscattering coefficient s0 in ESA ERS SAR PRI products , 1996 .

[22]  E. Bauer.  Statistical comparison of winds from ERS-1 scatterometer and ECMWF model in time and wavenumber domain , 1997 .

[23]  P. Vachon,et al.  Ship Detection by the RADARSAT SAR: Validation of Detection Model Predictions , 1997 .

[24]  David L. T. Anderson,et al.  Scatterometer data interpretation: Estimation and validation of the transfer function CMOD4 , 1997 .

[25]  D. R. Thompson,et al.  Polarization ratio for microwave backscattering from the ocean surface at low to moderate incidence angles , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[26]  Birgit Schättler,et al.  The ERS SAR Performances , 1998 .

[27]  S.K. Srivastava,et al.  RADARSAT image quality and calibration performance-update , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).