The role of the critical angle in brightness reversals on sunglint images of the sea surface

Jackson, Christopher; Alpers, Werner

doi:10.1029/2009jc006037

Cited by 113 publications

(91 citation statements)

References 25 publications

(50 reference statements)

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“…A wide variety of oceanic and atmospheric phenomena have been observed in and around the sun glint region on optical images of the sea surface (Jackson and Alpers 2010). A sun glint region is a region from which the satellite views the mirror-like reflection from the Sun.…”

Section: Satellite Sun Glint Imagesmentioning

confidence: 99%

“…The sun glint region can be modelled well for a known satellite orbit at a specific date/ time (Jackson and Alpers 2010;Zhang and Wang 2010). It is calculated using the latitude/ longitude points, Sun and satellite sensor azimuth and zenith angles, and ocean surface winds.…”

Section: Satellite Sun Glint Imagesmentioning

confidence: 99%

“…The bright patterns in the middle of the images are the sun glint areas, and the two red lines represent the sun glint boundaries for the MODIS images. In order to calculate the area of the sun glint, we first used the method of Jackson and Alpers (2010) to calculate the normalized sun glint radiance image and then applied empirical threshold value to obtain the sun glint edge pixels. After that, we applied the Canny (1986) edge detector to derive the boundaries of the sun glint.…”

Section: Satellite Sun Glint Imagesmentioning

confidence: 99%

“…Optical imaging is strongly dependent upon the viewing geometry. In a sun glint image, there normally exists a critical angle: a surface feature goes through a brightness reversal (Hu et al 2009;Jackson and Alpers 2010). Sea surface roughness variations associated with ISWs are visible on Synthetic Aperture Radar (SAR) as well as on visible images, but the dark and bright bands are ranked inversely which are also related to the polarity (Jackson and Alpers 2010).…”

Section: Extraction Of Internal Wave Crests From Sun Glint Imagesmentioning

confidence: 99%

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Tracking the internal waves in the South China Sea with environmental satellite sun glint images

Liu¹,

Hong²,

Ding³

et al. 2014

Remote Sensing Letters

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The propagation of internal solitary waves (ISWs) in the South China Sea (SCS) was tracked using National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS) sun glint image pairs. The acquisition times of the two images comprising the same pair is usually separated by about 2 hours. Four pairs of images in May and August 2013 were analysed. The ISW phase speeds were derived using the horizontal displacement of the ISW patterns and the time difference between the 2 satellite images. The phase speeds were in good agreement with the theoretical calculations using the Sturm-Louisville (S − L) equation with a non-linear term. Monthly ocean stratification data and bathymetry were used in the theoretical calculations. The ISW phase speeds are mainly affected by bottom depth, with seasonal variations. The ISWs propagated faster in August than in May. Our results also show that the ISW propagation in northern SCS can be mapped using environmental satellite sun glint images in short period of time with the advantage of large scale.

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Section: Satellite Sun Glint Imagesmentioning

confidence: 99%

Section: Satellite Sun Glint Imagesmentioning

confidence: 99%

Section: Satellite Sun Glint Imagesmentioning

confidence: 99%

Section: Extraction Of Internal Wave Crests From Sun Glint Imagesmentioning

confidence: 99%

See 2 more Smart Citations

Tracking the internal waves in the South China Sea with environmental satellite sun glint images

Liu¹,

Hong²,

Ding³

et al. 2014

Remote Sensing Letters

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“…According to the sun glitter geometry model, it has been found that the signature of sun glitter images depends strongly on the viewing angle. 19,23,24 He et al 25 discussed the brightness reversal of the Taiwan Banks submarine sand waves in sun glitter images from charge-coupled diodes onboard the HJ-1B satellite. Therefore, multiangle sun glitter images can present useful additional information compared with single angle images.…”

Section: Introductionmentioning

confidence: 99%

Bathymetric mapping of submarine sand waves using multiangle sun glitter imagery: a case of the Taiwan Banks with ASTER stereo imagery

Zhang

Yang

Lou

et al. 2015

J. Appl. Remote Sens

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Abstract. Submarine sand waves are visible in optical sun glitter remote sensing images and multiangle observations can provide valuable information. We present a method for bathymetric mapping of submarine sand waves using multiangle sun glitter information from Advanced Spaceborne Thermal Emission and Reflection Radiometer stereo imagery. Based on a multiangle image geometry model and a sun glitter radiance transfer model, sea surface roughness is derived using multiangle sun glitter images. These results are then used for water depth inversions based on the Alpers-Hennings model, supported by a few true depth data points (sounding data). Case study results show that the inversion and true depths match well, with high-correlation coefficients and root-mean-square errors from 1.45 to 2.46 m, and relative errors from 5.48% to 8.12%. The proposed method has some advantages over previous methods in that it requires fewer true depth data points, it does not require environmental parameters or knowledge of sand-wave morphology, and it is relatively simple to operate. On this basis, we conclude that this method is effective in mapping submarine sand waves and we anticipate that it will also be applicable to other similar topography types. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Sun glint requirement for the remote detection of surface oil films

Sun

2016

Geophysical Research Letters

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Natural oil slicks in the western Gulf of Mexico are used to determine the sun glint threshold required for optical remote sensing of oil films. The threshold is determined using the same‐day image pairs collected by Moderate Resolution Imaging Spectroradiometer (MODIS) Terra (MODIST), MODIS Aqua (MODISA), and Visible Infrared Imaging Radiometer Suite (VIIRS) (N = 2297 images) over the same oil slick locations where at least one of the sensors captures the oil slicks. For each sensor, statistics of sun glint strengths, represented by the normalized glint reflectance (LGN, sr−1), when oil slicks can and cannot be observed are generated. The LGN threshold for oil film detections is determined to be 10−5–10−6 sr−1 for MODIST and MODISA, and 10−6–10−7 sr−1 for VIIRS. Below these thresholds, no oil films can be detected, while above these thresholds, oil films can always be detected except near the critical‐angle zone where oil slicks reverse their contrast against the background water.

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The role of the critical angle in brightness reversals on sunglint images of the sea surface

Cited by 113 publications

References 25 publications

Tracking the internal waves in the South China Sea with environmental satellite sun glint images

Tracking the internal waves in the South China Sea with environmental satellite sun glint images

Bathymetric mapping of submarine sand waves using multiangle sun glitter imagery: a case of the Taiwan Banks with ASTER stereo imagery

Sun glint requirement for the remote detection of surface oil films

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