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Full-Text Articles in Engineering
Large-Scale Inverse Ku-Band Backscatter Modeling Of Sea Ice, David G. Long, Quinn P. Remund
Large-Scale Inverse Ku-Band Backscatter Modeling Of Sea Ice, David G. Long, Quinn P. Remund
Faculty Publications
Polar sea ice characteristics provide important inputs to models of several geophysical processes. Microwave scatterometers are ideal for monitoring these regions due to their sensitivity to ice properties and insensitivity to atmospheric distortions. Many forward electromagnetic scattering models have been proposed to predict the normalized radar cross section (σ˚) from sea ice characteristics. These models are based on very small scale ice features and generally assume that the region of interest is spatially homogeneous. Unfortunately, spaceborne scatterometer footprints are very large (5-50 km) and usually contain very heterogeneous mixtures of sea ice surface parameters. In this paper, we use scatterometer …
An Advanced Ambiguity Selection Algorithm For Seawinds, David G. Long, David W. Draper
An Advanced Ambiguity Selection Algorithm For Seawinds, David G. Long, David W. Draper
Faculty Publications
SeaWinds on QuikSCAT, a spaceborne Ku-band scatterometer, estimates ocean winds via the relationship between the normalized radar backscatter and the vector wind. Scatterometer wind retrieval generates several possible wind vector solutions or ambiguities at each resolution cell, requiring a separate ambiguity selection step to give a unique solution. In processing SeaWinds on QuikSCAT data, the ambiguity selection is "nudged" or initialized using numerical weather prediction winds. We describe a sophisticated new ambiguity selection approach developed at Brigham Young University (BYU) that does not require nudging. The BYU method utilizes a low-order data-driven Karhunen-Loeve wind field model to promote self-consistency. Ambiguity …
High-Resolution Measurements With A Spaceborne Pencil-Beam Scatterometer Using Combined Range/Doppler Discrimination Techniques, David G. Long, Michael W. Spencer, Wu-Yang Tsai
High-Resolution Measurements With A Spaceborne Pencil-Beam Scatterometer Using Combined Range/Doppler Discrimination Techniques, David G. Long, Michael W. Spencer, Wu-Yang Tsai
Faculty Publications
Conically scanning pencil-beam scatterometer systems, such as the SeaWinds radar, constitute an important class of instruments for spaceborne climate observation. In addition to ocean winds, scatterometer data are being applied to a wide range of land and cryospheric applications. A key issue for future scatterometer missions is improved spatial resolution. Pencil-beam scatterometers to date have been real-aperture systems where only range discrimination is used, resulting in a relatively coarse resolution of approximately 25 km. In this paper, the addition of Doppler discrimination techniques is proposed to meet the need for higher resolution. The unique issues associated with the simultaneous application …