An L-Band Ocean Geophysical Model Function Derived From PALSAR

Isoguchi, Osamu; Shimada, Masanobu

doi:10.1109/tgrs.2008.2010864

Cited by 107 publications

(54 citation statements)

References 23 publications

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“…The Negative Upwind-Crosswind (NUC) Asymmetry at low winds for VV and HH was reported in Isoguchi and Shimada [2009] and Yueh et al [2013], and now can also be found in the VH channel. The NUC feature is not expected to be a feature of Bragg scattering [Wu and Fung, 1972;Kudryavtsev et al, 2003] unless the directional spectrum of the ocean surface has the same NUC asymmetry.…”

Section: Aquarius Geophysical Model Functionmentioning

confidence: 70%

Aquarius geophysical model function and combined active passive algorithm for ocean surface salinity and wind retrieval

et al. 2014

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This paper describes the updated Combined Active-Passive (CAP) retrieval algorithm for simultaneous retrieval of surface salinity and wind from Aquarius' brightness temperature and radar backscatter. Unlike the algorithm developed by Remote Sensing Systems (RSS), implemented in the Aquarius Data Processing System (ADPS) to produce Aquarius standard products, the Jet Propulsion Laboratory's CAP algorithm does not require monthly climatology SSS maps for the salinity retrieval. Furthermore, the ADPS-RSS algorithm fully uses the National Center for Environmental Predictions (NCEP) wind for data correction, while the CAP algorithm uses the NCEP wind only as a constraint. The major updates to the CAP algorithm include the galactic reflection correction, Faraday rotation, Antenna Pattern Correction, and geophysical model functions of wind or wave impacts. Recognizing the limitation of geometric optics scattering, we improve the modeling of the reflection of galactic radiation; the results are better salinity accuracy and significantly reduced ascending-descending bias. We assess the accuracy of CAP's salinity by comparison with ARGO monthly gridded salinity products provided by the Asia-Pacific Data-Research Center (APDRC) and Japan Agency for Marine-Earth Science and Technology (JAMSTEC). The RMS differences between Aquarius CAP and APDRC's or JAMSTEC's ARGO salinities are less than 0.2 psu for most parts of the ocean, except for the regions in the Intertropical Convergence Zone, near the outflow of major rivers and at high latitudes.

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Section: Aquarius Geophysical Model Functionmentioning

confidence: 70%

Aquarius geophysical model function and combined active passive algorithm for ocean surface salinity and wind retrieval

et al. 2014

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“…This means that the normalized radar cross sections (NRCSs) at the crosswinds are larger than those upwind or downwind, while the upwind-crosswind asymmetry at high-frequency bands or at above 10 m/s wind speed is positive [3]. This phenomenon has been verified by several operated space-borne L-band scatterometers equipped on ALOS, Aquarius and SMAP [2,6]. However, there are thus far no theories or analytic models that can simulate this phenomenon [2,3].…”

Section: An Improved Directional Spectrummentioning

confidence: 95%

“…The first space-borne synthetic aperture radar (SAR) equipped on Seasat worked using L-band. Since then, several L-band active microwave sensors and missions have begun operation, which include the Japanese phased array type L-band synthetic Aperture Radar (PALSAR) [6], the Aquarius/SAC-D mission [7] and the Soil Moisture Active-Passive (SMAP) mission [8]. The Aquarius/SAC-D and SMAP missions, which were both undertaken by the U.S. National Aeronautics and Space Administration (NASA), have also used L-band microwave radiometers and combined active/passive L-band instruments for ocean research.…”

Section: Introductionmentioning

confidence: 99%

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An Improved Spectrum Model for Sea Surface Radar Backscattering at L-Band

Yang

Chen

et al. 2017

Remote Sensing

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L-band active microwave remote sensing is one of the most important technical methods of ocean environmental monitoring and dynamic parameter retrieval. Recently, a unique negative upwind-crosswind (NUC) asymmetry of L-band ocean backscatter over a low wind speed range was observed. To study the directional features of L-band ocean surface backscattering, a new directional spectrum model is proposed and built into the advanced integral equation method (AIEM). This spectrum combines Apel's omnidirectional spectrum and an improved empirical angular spreading function (ASF). The coefficients in the ASF were determined by the fitting of radar observations so that it provides a better description of wave directionality, especially over wavenumber ranges from short-gravity waves to capillary waves. Based on the improved spectrum and the AIEM scattering model, L-band NUC asymmetry at low wind speeds and positive upwind-crosswind (PUC) asymmetry at higher wind speeds are simulated successfully. The model outputs are validated against Aquarius/SAC-D observations under different incidence angles, azimuth angles and wind speed conditions.

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“…SEASAFE is currently ready to ingest X-band COSMO/SkyMed SAR images for wind extraction purposes; it is also ready to ingest L-band data (PALSAR-1) with the algorithm proposed by Isoguchi et al [11]; tests are ongoing with PALSAR-2 data.…”

Section: Wind and Wave Extraction From Sar Imagesmentioning

confidence: 99%

SEASAFE: an operational tool for sea surface monitoring with SAR

Biamino

Ananasso

Cavagnero

et al. 2015

Ravage of the Planet IV

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Synthetic Aperture Radar (SAR) is considered as a useful tool for sea surface monitoring, thanks to its capability to acquire images day and night and in all weather conditions. In particular, SAR is extensively used to detect oil slicks on the sea surface. Since the early 90s SAR acquisitions were routinely available with C-band sensors (such as ERS-1 and 2, Envisat, Radarsat 1 and 2). More recently, also L-band (ALOS PALSAR 1 and 2) and X-band (Terrasar X, COSMO/SkyMed constellation) sensors became operational. In this framework we developed a new software called SEASAFE (Slick Emissions And Ship Automatic Features Extraction), able to process SAR data in C-L-and X-bands. Moving from previous experience, new features have been added such as an enhanced land masking algorithm and oil spill characterization. Modules for ship detection and wind and wave evaluation are also available. The new improved system is here described; detection capabilities are evaluated, overall performances are described.

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An L-Band Ocean Geophysical Model Function Derived From PALSAR

Cited by 107 publications

References 23 publications

Aquarius geophysical model function and combined active passive algorithm for ocean surface salinity and wind retrieval

Aquarius geophysical model function and combined active passive algorithm for ocean surface salinity and wind retrieval

An Improved Spectrum Model for Sea Surface Radar Backscattering at L-Band

SEASAFE: an operational tool for sea surface monitoring with SAR

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