Comparison study of SEASAT scatterometer and conventional wind fields

• Main Author: Holderied, Kristine
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 1988
• Subjects: Winds; Ocean waves; Curl; North Atlantic
• Online Access: https://hdl.handle.net/1912/4954

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1988 This thesis is not subject to U.S. copyright. A demonstrated need exists for better wind field information over the open ocean, especially as a forcing function for ocean circulation models. Microwave scatterometry, as a means of remotely sensing surface wind information, developed in response to this requirement for a surface wind field with global coverage and improved spatial and temporal resolution. This development led to the 1978 deployment of the SEASAT Satellite Scatterometer (SASS). Evaluations of the three months of SEASAT data have established the consistency of SASS winds with high quality surface wind data from field experiments over limited areas and time periods. The directional ambiguity of the original SASS vectors has been removed by Atlas et al. (1987) for the entire data set, and the resulting SASS winds provide a unique set of scatterometer wind information for a global comparison with winds from conventional sources. A one-month (12 August to 9 September 1978) subset of these dealiased winds, in the western North Atlantic, is compared here with a conventional, pressure-derived wind field from the 6-hourly surface wind analyses of the Fleet Numerical Oceanographic Center (FNOC), Monterey, CA. Through an objective mapping procedure, the irregularly spaced SASS winds are regridded to a latitude-longitude grid, facilitating statistical comparisons with the regularly spaced FNOC wind vectors and wind stress curl calculations. The study includes qualitative comparisons to synoptic weather maps; calculations of field statistics and boxed mean differences; scatter plots of wind speed, direction, and standard deviation; statistical descriptions of the SASS-FNOC difference field, and wind stress curl calculations. The SASS and FNOC fields are consistent with each other in a broad statistical sense, with ...