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Lawrence W Shacklette - One of the best experts on this subject based on the ideXlab platform.

Xiaoxiong Xiong - One of the best experts on this subject based on the ideXlab platform.

  • IGARSS - Preliminary JPSS-3 VIIRS Polarization Sensitivity and Comparison with S-NPP, JPSS-1 and ‐2
    IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium, 2020
    Co-Authors: David Moyer, Xiaoxiong Xiong, Jeff Mcintire, Kurtis Thome
    Abstract:

    The Visible-Infrared Imaging Radiometer Suite (VIIRS) was first launched on-board the Suomi National Polar-orbiting Partnership (S-NPP) spacecraft in October of 2011. There have been three subsequent builds of the VIIRS sensor for the Joint Polar Satellite System (JPSS) program with JPSS-1, ‐2 and ‐3 having launch dates of November 2017, March 2022 and 2026 respectively. There is also a JPSS-4 VIIRS, that is in hardware integration during 2020, with a launch date of 2031. VIIRS has 22 bands: 7 thermal emissive bands (TEBs), 14 reflective solar bands (RSBs) and a Day Night Band (DNB). Ocean Color/Chlorophyll (OCC) products use calibrated Science Data Records (SDRs) for bands M1-M7 ( 0.412-0.865\ \mu\mathrm{m}$ ) to compute their ocean chemistry products. These bands require accurate Polarization Sensitivity characterization to compensate for polarized upwelling Rayleigh scatter and produce accurate OCC Environment Data Products (EDRs). VIIRS Polarization Sensitivity requirement failures have driven hardware modifications to the bandpass filters and dichroic beam splitter over the program. This paper will discuss the preliminary JPSS-3 Polarization results and how these hardware modifications, as the JPSS program progresses, have affected the sensor performance. Comparisons of the Polarization sensitivities between sensor builds will be discussed along with the hardware modifications that contributed to their differences.

  • Assessment of VIIRS on-orbit Polarization Sensitivity and its impact on CLARREO pathfinder inter-calibration
    Sensors Systems and Next-Generation Satellites XXIII, 2019
    Co-Authors: Xiaoxiong Xiong, Constantine Lukashin
    Abstract:

    The primary objective of the CLARREO Pathfinder (CPF) mission is to demonstrate essential measurement technologies to enable highly accurate decadal change observations traceable on-orbit to SI standards. Another important objective of the CPF is to demonstrate inter-calibration with the VIIRS sensor and to show that such high-accuracy reference inter-calibration is achievable. To satisfy this requirement, it is important to understand and quantify uncertainties in VIIRS sensor measurements. Based on prelaunch test results, the reflective solar bands of both SNPP and NOAA-20 VIIRS have exhibited Polarization sensitivities in the shortest wavelength bands, with an unexpectedly larger Sensitivity observed for NOAA-20 VIIRS, particularly in bands M1 to M4. In this study, we use VIIRS Level-1B reflectance data collected over the Pseudo-Invariant Calibration Sites over North African desert region to examine the Polarization associated uncertainty for these four bands. Impact due to BRDF on the reflectance data is considered by comparing baseline results obtained from the same viewing and solar zenith angles under relatively low Polarization Sensitivity. Impact due to detector relative difference in Polarization Sensitivity is examined by normalizing reflectances by the value of the middle detector. Results of this study provide useful information on VIIRS uncertainty contribution due to Polarization when conducting CPF and VIIRS inter-calibration.

  • Assessment of Terra MODIS On-Orbit Polarization Sensitivity Using Pseudoinvariant Desert Sites
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Xu Geng, Andrew Wald, Amit Angal, Xiaoxiong Xiong
    Abstract:

    The Moderate Resolution Imaging Spectroradiometer (MODIS) is currently flying on NASA’s Earth Observing System Terra and Aqua satellites, launched in 1999 and 2002, respectively. MODIS reflective solar bands in the visible wavelength range are known to be sensitive to polarized light based on prelaunch Polarization Sensitivity tests. After about five years of on-orbit operations, it was discovered that the Polarization Sensitivity at short wavelengths had shown a noticeable increase. In this paper, we examine the impact of Polarization on measured top-of-atmosphere (TOA) reflectances based on MODIS Collection-6 L1B over pseudoinvariant desert sites. The standard Polarization correction equation is used in combination with simulated at-sensor radiances using the second simulation of a satellite signal in the Solar Spectrum, Vector Radiative Transfer Code (6SV). We ignore the Polarization contribution from the surface and a ratio approach is used for both 6SV-derived input parameters and observed TOA reflectances. Results indicate that significant gain corrections up to 25% are required near the end of scan for the 412 and 443 nm bands. The Polarization correction reduces the seasonal fluctuations in reflectance trends and mirror side ratios from 30% and 12% to 10% and 5%, respectively, for the two bands. Comparison of the effectiveness of the Polarization correction with the results from the NASA Ocean Biology Processing Group shows a good agreement in the corrected reflectance trending results and their seasonal fluctuations.

  • Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite Polarization Sensitivity analysis.
    Applied optics, 2016
    Co-Authors: Jun-qiang Sun, Eugene Waluschka, Xiaoxiong Xiong, Menghua Wang
    Abstract:

    The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of five instruments onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite that launched from Vandenberg Air Force Base, California, on October 28, 2011. It is a whiskbroom radiometer that provides ±56.28° scans of the Earth view. It has 22 bands, among which 14 are reflective solar bands (RSBs). The RSBs cover a wavelength range from 410 to 2250 nm. The RSBs of a remote sensor are usually sensitive to the Polarization of incident light. For VIIRS, it is specified that the Polarization factor should be smaller than 3% for 410 and 862 nm bands and 2.5% for other RSBs for the scan angle within ±45°. Several Polarization Sensitivity tests were performed prelaunch for SNPP VIIRS. The first few tests either had large uncertainty or were less reliable, while the last one was believed to provide the more accurate information about the Polarization property of the instrument. In this paper, the measured data in the last Polarization Sensitivity test are analyzed, and the Polarization factors and phase angles are derived from the measurements for all the RSBs. The derived Polarization factors and phase angles are band, detector, and scan angle dependent. For near-infrared bands, they also depend on the half-angle mirror side. Nevertheless, the derived Polarization factors are all within the specification, although the strong detector dependence of the Polarization parameters was not expected. Compared to the Moderate Resolution Imaging Spectroradiometer on both Aqua and Terra satellites, the Polarization effect on VIIRS RSB is much smaller.

  • Monochromatic measurements of the JPSS-1 VIIRS Polarization Sensitivity.
    Applied optics, 2016
    Co-Authors: Jeff Mcintire, Eugene Waluschka, David Moyer, Hassan Oudrari, Steven W. Brown, Keith R. Lykke, Xiaoxiong Xiong
    Abstract:

    Polarization Sensitivity is a critical property that must be characterized for spaceborne remote sensing instruments designed to measure reflected solar radiation. Broadband testing of the first Joint Polar-orbiting Satellite System (JPSS-1) Visible Infrared Imaging Radiometer Suite (VIIRS) showed unexpectedly large Polarization sensitivities for the bluest bands on VIIRS (centered between 400 and 600 nm). Subsequent ray trace modeling indicated that large diattenuation on the edges of the bandpass for these spectral bands was the driver behind these large sensitivities. Additional testing using the National Institute of Standards and Technology’s Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources was added to the test program to verify and enhance the model. The testing was limited in scope to two spectral bands at two scan angles; nonetheless, this additional testing provided valuable insight into the Polarization Sensitivity. Analysis has shown that the derived diattenuation agreed with the broadband measurements to within an absolute difference of about 0.4% and that the ray trace model reproduced the general features of the measured data. Additionally, by deriving the spectral responsivity, the linear diattenuation is shown to be explicitly dependent on the changes in bandwidth with Polarization state.

Gábor Horváth - One of the best experts on this subject based on the ideXlab platform.

  • Polarization Sensitivity in Collembola: an experimental study of polarotaxis in the water-surface-inhabiting springtail Podura aquatica.
    The Journal of Experimental Biology, 2016
    Co-Authors: Ádám Egri, Alexandra Farkas, György Kriska, Gábor Horváth
    Abstract:

    ABSTRACT The ventral eye of the water-surface-inhabiting springtail Podura aquatica has six ommatidia with horizontal and vertical microvilli and perceives light from the ventral, frontal and frontodorsal regions, whereas the dorsal eye possesses two upward-looking ommatidia with vertical microvilli. The ventral eye may detect water by its Polarization Sensitivity, even if the insect is resting with its head slightly tipped down on a raised surface. The Polarization Sensitivity and polarotaxis in springtails (Collembola) have not been investigated. Therefore, we performed behavioural choice experiments to study them in P. aquatica . We found that the strength of phototaxis in P. aquatica depends on the Polarization characteristics of stimulating light. Horizontally and vertically polarized light were the most and least attractive, respectively, while unpolarized stimulus elicited moderate attraction. We show that horizontally polarized light attracts more springtails than unpolarized, even if the polarized stimulus was 10 times dimmer. Thus, besides phototaxis, P. aquatica also performs polarotaxis with the ability to measure or at least estimate the degree of Polarization. Our results indicate that the threshold d * of Polarization Sensitivity in P. aquatica is between 10.1 and 25.5%.

  • Polarization Sensitivity in Collembola: an experimental study of polarotaxis in the water-surface-inhabiting springtail
    2016
    Co-Authors: Ádám Egri, Alexandra Farkas, György Kriska, Gábor Horváth
    Abstract:

    The 6-ommatidium ventral eye of the water-surface-inhabiting springtail Poduara aquatica has horizontal and vertical microvilli and perceives light from the ventral, frontal and frontodorsal regions, while the 2-ommatidium dorsal eye possesses two upward-looking ommatidia with vertical microvilli. The ventral eye may serve water detection by its Polarization Sensitivity, even if the insect is resting with its head slightly tipped down on a raised surface. The Polarization Sensitivity and polarotaxis in springtails (Collembola) have not been investigated. Therefore, we performed behavioural choice experiments to study them in P. aquatica. We found that the strength of phototaxis in P. aquatica depends on the Polarization characteristics of stimulating light. Horizontally and vertically polarized light were the most and least attractive, respectively, while unpolarized stimulus elicited moderate attraction. We showed that horizontally polarized light attracted more springtails than unpolarized, even if the polarized stimulus was 10 times dimmer. Thus, besides phototaxis, P. aquatica also has polarotaxis with the ability to measure or at least estimate the degree of Polarization. Our results indicate that the threshold d* of Polarization Sensitivity in P. aquatica is between 10.1 and 25.5 %.

  • Polarization Sensitivity in Crustaceans
    Polarized Light in Animal Vision, 2004
    Co-Authors: Gábor Horváth, Dezső Varjú
    Abstract:

    To our knowledge, the first animals in which Polarization Sensitivity has been demonstrated were certain entomostracan crustaceans (Verkhovskaya 1940) and the horseshoe crab Limulus ( Waterman 1950). However, so far the behavioural or ecological significance of this ability in these arthropods is unknown.

  • Polarization Sensitivity in Fish
    Polarized Light in Animal Vision, 2004
    Co-Authors: Gábor Horváth, Dezső Varjú
    Abstract:

    Polarization Sensitivity (PS) has been studied in several groups of teleost fish with different methods, ranging from orientation experiments to single-unit recordings from the optic tectum. Kawamura et al. (1981), for instance, found that by changing the direction of Polarization, the heart-beat rate decreases in several fish species. This effect is called “bradycardia”. The significance of this physiological change is not clear, but the response has been proven useful to investigate PS in fish.

  • From Polarization Sensitivity to Polarization Vision
    Polarized Light in Animal Vision, 2004
    Co-Authors: Gábor Horváth, Dezső Varjú
    Abstract:

    The forerunners of the study of Polarization Sensitivity in animals are Santschi (1923), Crozier and Mangelsdorf (1924), Verkhovskaya (1940) and Frisch (1949). In one of his behavioural experiments, Santschi depolarized the skylight with a ground glass disk held above an ant running on the ground to its nest. He observed that the ant suddenly stopped and searched around randomly. However, from this disorientation he did not draw the conclusion that the ant could perceive the Polarization of skylight ( Wehner and Rossel 1985, p. 13). This hindered him to discover that certain ants can perceive the skylight Polarization and use it for navigation.

Han Zou - One of the best experts on this subject based on the ideXlab platform.

Justin Marshall - One of the best experts on this subject based on the ideXlab platform.

  • Polarization Sensitivity in two species of cuttlefish - Sepia plangon (Gray 1849) and Sepia mestus (Gray 1849) - demonstrated with polarized optomotor stimuli.
    The Journal of Experimental Biology, 2010
    Co-Authors: Christopher M. Talbot, Justin Marshall
    Abstract:

    SUMMARY The existence of Polarization Sensitivity (PS), most likely resulting from the orthogonal arrangement of microvilli in photoreceptors, has been proposed in cephalopods for some time, although it has rarely been examined behaviourally. Here, we tested the mourning cuttlefish, Sepia plangon, and the reaper cuttlefish, Sepia mestus, for Polarization Sensitivity using a large-field optomotor stimulus containing Polarization contrast. Polaroid filter drums with stripes producing alternating e-vectors were rotated around free-moving animals. Polarized optomotor responses were displayed, and these responses were similar to those performed in response to a black-and-white, vertically-striped drum, whereas no responses were displayed to a plain polarizing control drum producing just a vertical e-vector. This indicates that the animals are able to see the contrast between adjacent stripes in the polarizing drum. To our knowledge, this is the first demonstration of functional Polarization Sensitivity in cuttlefish.

  • Polarization Sensitivity and retinal topography of the striped pyjama squid (Sepioloidea lineolata - Quoy/Gaimard 1832).
    Journal of Experimental Biology, 2010
    Co-Authors: Christopher M. Talbot, Justin Marshall
    Abstract:

    Coleoid cephalopods (octopus, cuttlefish and squid) potentially possess Polarization Sensitivity (PS) based on photoreceptor structure, but this idea has rarely been tested behaviourally. Here, we use a polarized, striped optokinetic stimulus to demonstrate PS in the striped pyjama squid, Sepioloidea lineolata . This species displayed strong, consistent optokinetic nystagmic eye movements in response to a drum with stripes producing e-vectors set to 0 deg, 45 deg, 90 deg and 135 deg that would only be visible to an animal with PS. This is the first behavioural demonstration of a polarized optokinetic response in any species of cephalopod. This species, which typically sits beneath the substrate surface looking upwards for potential predators and prey, possesses a dorsally shifted horizontal pupil slit. Accordingly, it was found to possess a horizontal strip of high-density photoreceptors shifted ventrally in the retina, suggesting modifications such as a change in Sensitivity or resolution to the dorsal visual field. * OKR : optokinetic response OMR : optomotor response PS : Polarization Sensitivity