An efficient, physics-based remote bathymetry method for the littoral zone is described and illustrated with applications to QuickBird, Littoral Airborne Sensor: Hyperspectral (LASH), and Airborne ...Visible/Infrared Spectrometer (AVIRIS) spectral imagery. The method combines atmospheric correction, water reflectance spectral simulations, and a linear unmixing bathymetry algorithm that accounts for water surface reflections, thin clouds, and variable bottom brightness, and can incorporate blends of bottom materials. Results include depth maps, bottom color visualizations, and in favorable cases, approximate descriptions of the water composition. In addition, atmospheric correction was advanced through new capabilities added to the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) and Moderate Resolution Transmittance (MODTRAN) codes, including characterization of the aerosol wavelength dependence and a discrete-ordinate-method radiative transfer scaling technique for rapid calculation of multiply scattered radiance.
An improved kinetic model for the Meinel bands of OH has been constructed from rate constants and Einstein A coefficients derived in recent laboratory experiments. Using a semiempirical ...parameterization of the state‐to‐state rate constants for OH(v) quenching by O2, the absolute OH(v) nightglow radiances are modeled to within the accuracies of the atmospheric constituent concentrations and the radiometric calibrations. Collisional quenching is found to be predominantly multiquantum at high v but single‐quantum at low v.
We present the accuracy requirements for specific kinetic and spectroscopic parameters used in modeling populations of vibrationally excited hydroxyl. The requirements are based on simulations of the ...inference of chemical energy deposition rates and atomic hydrogen densities from satellite observations of the hydroxyl Meinel band emission rates. Improvement in the rate constants which describe the collisional removal of the high‐lying υ states of OH and the reaction of highlying υ states with atomic oxygen is required in addition to improved specification of the nascent distribution of energy within OH upon reaction of atomic hydrogen and ozone. These improvements are necessary for the interpretation of Meinel band measurements to be made from a new spaceflight experiment in less than 3 years.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Spectroscopic data and reaction rate coefficients pertinent to ozone in the mesosphere and thermosphere (altitude >50 km) are critically surveyed. These data should be of use in modeling atmospheric ...infrared luminescence, measuring atmospheric ozone concentrations by remote sensing, and designing and interpreting laboratory measurements. There is a clear need for additional data on metastable ozone electronic states, additional atmospheric ozone formation channels, collision processes involving electrons and ions, and vibrational state dependence of reaction rate coefficients.
First-principles atmospheric compensation of Earth-viewing spectral imagery requires atmospheric property information derived from the image itself or measured independently. A field experiment was ...conducted in May, 2003 at Davis, CA to investigate the consistency of atmospheric properties and surface reflectances derived from simultaneous ground-, aircraft- and satellite-based spectral measurements. The experiment involved the simultaneous collection of HyMap hyperspectral and Landsat-7 multispectral imagery, in situ reflectance spectra of calibration surfaces, and sun and sky radiances from ultraviolet and visible multifilter rotating shadowband radiometers (MFRSRs). The data were analyzed using several different radiation transport and atmospheric compensation algorithms. Reasonable self-consistency was found between aerosol property retrievals from the radiometers and from dark pixels of the imagery, and, when using the most accurate algorithm, there was excellent agreement between the retrieved surface spectra and the ground truth measurements.
In this tutorial overview, we examine atmospheric compensation of hyperspectral data in the visible and nearinfrared (VNIR)-short-wave infrared (SWIR) region. The background is discussed, including ...the motivation for and a brief history of image compensation. Atmospheric characteristics are presented to highlight important optical effects that must be mitigated (i.e., atmospheric absorption and scattering). A full radiative transfer (RT) expression with simplifications is presented, resulting in formulations that are solved in terms of reflectance.
Detailed spectroscopic analysis of hydroxyl fundamental vibration‐rotation and pure rotation emission lines has yielded OH(υ,N) absolute column densities for nighttime earthlimb spectra in the 20 to ...110‐km tangent height region. High‐resolution spectra were obtained in the Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS 1A) experiment. Rotationally thermalized populations in υ = 1–9 have been derived from the fundamental bands between 2000 and 4000 cm−1. Highly rotationally excited populations with N ≤ 33 ( ≤ 2.3 eV rotational energy) have been inferred from the pure rotation spectra between 400 and 1000 cm−1. These emissions originate in the airglow region near 85–90 km altitude. Spectral fits of the pure rotation lines imply equal populations in the spinrotation states F1 and F2 but a ratio Π(A′):Π(A″) = 1.8±0.3 for the Λ‐doublet populations. A forward predicting, first‐principles kinetic model has been developed for the resultant OH(υ,N) limb column densities. The kinetic model incorporates a necessary and sufficient number of processes known to generate and quench OH(υ,N) in the mesopause region and includes recently calculated vibration‐rotation Einstein coefficients for the high‐N levels. The model reproduces both the thermal and the highly rotationally excited OH(υ,N) column densities. The tangent height dependence of the rotationally excited OH(υ,N) column densities is consistent with two possible formation mechanisms: (1) transfer of vibrational to rotational energy induced by collisions with O atoms or (2) direct chemical production via H + O3 → OH(υ,N) + O2.
An alternative formulation of the Langley plot relating observed solar irradiance, extraterrestrial solar irradiance, and air mass has been suggested to potentially improve radiometer calibration ...accuracy. In this study, results from the traditional and alternative plotting methods are compared using both simulated and measured data. The simulations indicate that their relative accuracies depend on the time scale of the atmospheric extinction fluctuations. The two methods are found to be essentially equivalent with the measured data. PUBLICATION ABSTRACT
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The formalism of anomalous change detection, which was developed for finding unusual changes in pairs of images, is extended to sequences of more than two images. Extended algorithms based on RX, ...Chronochrome, and Hyper are presented for identifying the most anomalously changing pixels in a sequence of co-registered images. Experimental comparisons are performed both on real data with real anomalies and on real data with simulated anomalies.
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