Changes In Reflection Characteristics Research Articles

A Bird's-Eye View: Novel Use of Drone Images to Quantify Differences in Altitudinal Reflections in Bird-window Collision Studies

Bird-window collisions (BWCs) constitute a significant source of mortality for both resident and migratory birds. Because windows reflect surrounding landscape components, such as vegetation or sky, birds do not always perceive glass as a barrier. Here we demonstrate a novel technique to classify and quantify reflections in windows on the Radford University campus in southwest Virginia, U.S.A. We deployed a consumer-grade Unmanned Aerial Vehicle, i.e., drone, to photograph 14 contiguous or near-contiguous window columns across five campus buildings in August 2020. For each study aspect, the drone (equipped with an RGB camera) captured images at ca. 5 m altitudinal increments from the ground floor to the roof of each building (three to six images/vertical column). We then manually classified each image in ImageJ to calculate approximate proportions of reflected: (1) vegetation, (2) sky, (3) and artificial structures or impervious surfaces, plus (4) nonreflective glass. We used a generalized linear model to determine how proportional reflections of vegetation, sky, buildings, and nonreflective glass varied across vertical increments. We found the proportion of sky significantly decreased with increasing photo heights, whereas proportion of nonreflective glass significantly increased with increasing heights. This supports previous findings that because birds are drawn to sky reflections, they may collide at relatively lower positions on buildings. Inconsistency in landscape design and building positioning on the campus precluded trends in vegetative or building reflections by height. Our pilot study demonstrates the applicability of a consumer-grade drone for investigating visual characteristics of reflections that influence BWCs from variable observation angles. We suggest the expanded use of drone images as a straightforward technique to measure changes in reflection characteristics from varying degrees of observation. They are a novel method in developing a BWC risk assessment as well as potential mitigation strategies in a suburban or campus environment with buildings of intermediate heights.

Remote sensing-based mapping of the destruction to Aleppo during the Syrian Civil War between 2011 and 2017

Accurate assessment of damage caused by conflict can be difficult to determine from ground-based surveys, particularly in the context of violence and unsafe conditions. Earth Observation data provides a non-invasive method for rapid damage assessment over wide geographic areas. In this study we use Landsat Imagery captured between 2011 and 2017 to assess the damage in Aleppo, Syria caused by conflict during the Syrian Civil War. Extracting temporal changes in urban environments is complex and the capabilities of traditional spectral-based methodologies are limited. We examined the effectiveness of the Gray-Level Co-Occurrence Matrix (GLCM) and two texture-based metrics (correlation and homogeneity) at classifying changes in reflectance characteristics within urban environments caused by building damage and consequent changes in surface orientation. Homogeneity was a more effective texture measure than correlation (overall accuracy of 79% vs 50%). Results indicated that between 45% and 57% of Aleppo was damaged during the study period, including up to 57% of former rebel held areas and between 34% and 46% of government areas and their surrounds. We used SPOT-6 imagery for accuracy assessment. Damage to Aleppo has yet to be fully quantified and several parts of the city remain unsafe and inaccessible. The results of this study highlight the potential offered by texture analysis for mapping damage to urban areas with freely available imagery and can be readily applied to natural disasters such as earthquakes and the aftermath of extreme weather events.

Evaluating Leaf and Canopy Reflectance of Stressed Rice Plants to Monitor Arsenic Contamination.

Arsenic contamination is a serious problem in rice cultivated soils of many developing countries. Hence, it is critical to monitor and control arsenic uptake in rice plants to avoid adverse effects on human health. This study evaluated the feasibility of using reflectance spectroscopy to monitor arsenic in rice plants. Four arsenic levels were induced in hydroponically grown rice plants with application of 0, 5, 10 and 20 µmol·L−1 sodium arsenate. Reflectance spectra of upper fully expanded leaves were acquired over visible and infrared (NIR) wavelengths. Additionally, canopy reflectance for the four arsenic levels was simulated using SAIL (Scattering by Arbitrarily Inclined Leaves) model for various soil moisture conditions and leaf area indices (LAI). Further, sensitivity of various vegetative indices (VIs) to arsenic levels was assessed. Results suggest that plants accumulate high arsenic amounts causing plant stress and changes in reflectance characteristics. All leaf spectra based VIs related strongly with arsenic with coefficient of determination (r2) greater than 0.6 while at canopy scale, background reflectance and LAI confounded with spectral signals of arsenic affecting the VIs’ performance. Among studied VIs, combined index, transformed chlorophyll absorption reflectance index (TCARI)/optimized soil adjusted vegetation index (OSAVI) exhibited higher sensitivity to arsenic levels and better resistance to soil backgrounds and LAI followed by red edge based VIs (modified chlorophyll absorption reflectance index (MCARI) and TCARI) suggesting that these VIs could prove to be valuable aids for monitoring arsenic in rice fields.

PALAEOCEANOGRAPHIC INTERPRETATION OF A SEISMIC PROFILE FROM THE SOUTHERN MOZAMBIQUE RIDGE, SOUTHWESTERN INDIAN OCEAN

Seismic reflection data from the southern Mozambique Ridge, Southwestern Indian Ocean, show indications for a modification in the oceanic circulation system during the Neogene. Major reorganisations in the Indian Ocean circulation system accompanying the closure of the Indonesian Gateway led to the onset of current controlled sedimentation in the vicinity of the Mozambique Ridge at ~14 Ma. The modifications in water mass properties and path are documented in changes in reflection characteristics in the Mozambique Ridge area. Correlating these with identified changes of the Nd isotope evolution in deep water masses the general present day large scale circulation in the southern Indian Ocean is suggested to have prevailed for the last 9 Ma. References should not be included in abstracts.

Using temporal averaging to decouple annual and nonannual information in avhrr ndvi time series

As regularly spaced time series imagery becomes more prevalent in the remote sensing community, monitoring these data for temporal consistency will become an increasingly important problem. Long-term trends must be identified, and it must be determined if such trends correspond to true changes in reflectance characteristics of the study area (natural), or if their source is a signal collection and/or processing artifact that can be identified and corrected in the data (artificial). Spectrally invariant targets (SITs) are typically used for sensor calibration and data consistency checks. Unfortunately, such targets are not always available in study regions. The temporal averaging technique described in this research can be used to determine the presence of artificial interannual value drift in any region possessing multiyear regularly sampled time series remotely sensed imagery. Further, this approach is objective and does not require the prior identification of a SIT within the region of study. Using biweekly Advanced Very High Resolution Radiometer (AVHRR) normalized difference vegetation index (NDVI) data from 1990 to 2001 covering the conterminous United States, an interannual trend present in the entire scene was identified using the proposed technique and found to correspond extremely well with interannual trends identified using two SITs within the region.

Firing through Porous Silicon Antireflection Coating for Silicon Solar Cells

The new idea to realize contacts through a porous silicon (PS) antireflection coating (ARC) is tested for the first time from the viewpoint of PS eligibility towards a rapid high-temperature process. The morphological analysis (TEM and SE) reveals that the thickness of PS after the thermal treatment is slightly increased accompanied by an increase of its porosity. As a result no significant changes in reflectance characteristics are observed. Therefore it can be successfully used as an alternative way for preparation of PS ARC for silicon solar cells.

Seismic Stratigraphy of Baltimore Canyon Trough

Examination of approximately 3,000 km of multichannel seismic-reflection profiles collected over the U.S. Middle Atlantic Shelf (Cape Hatteras to Long Island) shows that the margin was rifted prior to the separation of Africa and North America and that it broadly subsided after the separation. Major accumulation of sediment is centered in the Baltimore Canyon Trough, where more than 15 km of Triassic(?) and younger sedimentary rocks has been deposited. The trough is asymmetric in that the thickest sedimentary section is beneath the outer part of the shelf seaward of a hinge zone; further, the trough is wider on the north off New Jersey than it is seaward of Virginia. Flanking the trough are two block-fault platforms (Long Island and Carolina) where thickness of the sedime tary cover is 1 to 4 km. Eight depositional sequences have been delineated in analysis of the profiles by use of the techniques Vail and others have presented in AAPG Memoir 26. Marked changes in reflection characteristics and unconformities are used to bound the sequences. The oldest sequence (Late Triassic-Early Jurassic) is thought to be nonmarine and restricted-marine sediments associated with a complexly faulted crust. The changing seismic facies of younger sequences chronicle the transition to more open marine shelf and slope paleoenvironments during the Cretaceous and Tertiary. The thickest units accumulated during a phase of rapid basin subsidence in the Jurassic; sediment accumulation decreased substantially during the Late Cretaceous and Cenozoic so that the sequences are thinner and unconformities re more evident. The most conspicuous unconformities seismically are correlated with the Albian, Turonian-Coniacian, Late Cretaceous-Paleocene, Oligocene, and late Miocene-early Pliocene, by correlation with COST (Continental Offshore Stratigraphic Test) and coastline wells. Several of these breaks coincide with pronounced fluctuations in the Vail curve of relative sea level, particularly during the Tertiary, when indications of falling sea level were widespread. Lastly, the records confirm the presence of a carbonate platform along the seaward edge of the trough during the Jurassic and Early Cretaceous. The stages of formation of the continental margin here are similar to those of the margin off the Canadian Maritime Provinces.

Color Assessment of Experimentally Pigmented Rainbow Trout

The development of color in the muscle of pen‐reared rainbow trout, Salmo gairdneri, resulted from the absorption and deposition of astaxanthin introduced into the diet. The degree of coloration compared to that of control fish, fed diets naturally low in pigment, was easily evaluated visually. The major change in reflectance characteristics on increased pigmentation involved increase in light absorption at shorter wavelengths (astaxanthin absorption maximum ca. 490–500 nm) manifested by decreased CIE Z and increase in excitation purity Pe. Indeed, either Z or Pe alone ranked samples in close agreement with visual scores. No other single colorimetric quantity in any of the Jour systems studied shared this property. To relate colorimetric measurements in Hunter L a b, CIELUV, and CIELAB to visual scores, one had to resort to multiple‐regression analysis. This increased the complexity of the analysis without offering any advantage. Pigment concentration alone cannot be used as a criterion of perceived coloration. Both reflectance measurements and visual appearance were profoundly affected by differences in properties of the light‐scattering cellular matrix at constant pigment concentration.