Engineering topics

Mcgoldrick, L. F.

Publications and source records attributed to Mcgoldrick, L. F..

3 records

NASA NTRS1986

The necessity for a new parameterization of an empirical model for wind/ocean scatterometry

Difficulties related to the paucity of weather observation data regarding oceans were potentially alleviated for three summer months in 1978 when NASA's Seasat telemetered data from three wind-measuring instruments. The present study is concerned with one of these instruments, the Seasat A Scatterometer System (SASS). Attention is given to an internal consistency check of the SASS 1 model, comparisons of SASS 1 and other model-predicted winds with in situ winds, and a brief summary of the principal findings. It is found that a new wind retrieval system is required if SASS wind data are to be globally applicable and, at the same time, are to meet the required performance specifications. The sum-of-squares (SOS) technique for inverting SASS NRCS (normalized radar cross section) measurements results in the discarding of valuable data in low-speed areas and for higher incidence angles.

Woiceshyn, P. M.↗

NASA NTRS1984

Remote sensing for oceanography: Past, present, future

Oceanic dynamics was traditionally investigated by sampling from instruments in situ, yielding quantitative measurements that are intermittent in both space and time; the ocean is undersampled. The need to obtain proper sampling of the averaged quantities treated in analytical and numerical models is at present the most significant limitation on advances in physical oceanography. Within the past decade, many electromagnetic techniques for the study of the Earth and planets were applied to the study of the ocean. Now satellites promise nearly total coverage of the world's oceans using only a few days to a few weeks of observations. Both a review of the early and present techniques applied to satellite oceanography and a description of some future systems to be launched into orbit during the remainder of this century are presented. Both scientific and technologic capabilities are discussed.

Mcgoldrick, L. F.↗

NASA NTRS1984

A new parameterization of an empirical model for wind/ocean scatterometry

The power law form of the SEASAT A Scatterometer System (SASS) empirical backscatter-to-wind model function does not uniformly meet the instrument performance over the range 4 to 24 /ms. Analysis indicates that the horizontal polarization (H-Pol) and vertical polarization (V-Pol) components of the benchmark SASS1 model function yield self-consistent results only for a small mid-range of speeds at larger incidence angles, and for a somewhat larger range of speeds at smaller incidence angles. Comparison of SASS1 to in situ data over the Gulf of Alaska region further underscores the shortcomings of the power law form. Finally, a physically based empirical SASS model is proposed which corrects some of the deficiencies of power law models like SASS1. The new model allows the mutual determination of sea surface wind stress and wind speed in a consistent manner from SASS backscatter measurements.

Woiceshyn, P. M.↗