scholarly journals Radiometric Performance Evaluation of FY-4A/AGRI Based on Aqua/MODIS

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1859
Author(s):  
Bo Zhong ◽  
Yingbo Ma ◽  
Aixia Yang ◽  
Junjun Wu
Keyword(s):  
Near Infrared ◽  
Spectral Response ◽  
Convective Cloud ◽  
Radiation Level ◽  
High Attenuation ◽  
Total Attenuation ◽  
Attenuation Rate ◽  
Calibration Facility ◽  
Deep Convective Cloud ◽  
Directional Reflectance

Fengyun-4A (FY-4A) is the first satellite of the Chinese second-generation geostationary orbit meteorological satellites (FY-4). The Advanced Geostationary Radiation Imager (AGRI), onboard FY-4A does not load with high-precision calibration facility in visible and near infrared (VNIR) channel. As a consequence, it is necessary to comprehensively evaluate its radiometric performance and quantitatively describe the attenuation while using its VNIR data. In this paper, the radiometric performance at VNIR channels of FY-4A/AGRI is evaluated based on Aqua/MODIS data using the deep convective cloud (DCC) target. In order to reduce the influence of view angle and spectral response difference, the bi-directional reflectance distribution function (BRDF) correction and spectral matching have been performed. The evaluation result shows the radiometric performance of FY-4A/AGRI: (1) is less stable and with obvious fluctuations; (2) has a lower radiation level because of 24.99% lower compared with Aqua/MODIS; 3) has a high attenuation with 9.11% total attenuation over 2 years and 4.0% average annual attenuation rate. After the evaluation, relative radiometric normalization between AGRI and MODIS in VNIR channel is performed and the procedure is proved effective. This paper proposed a more reliable reference for the quantitative applications of FY-4A data.

Effects of Metal Stress on Visible/Near-Infrared Reflectance Spectra of Vegetation

2011 ◽  
Vol 347-353 ◽  
pp. 2735-2738 ◽  
Author(s):  
Guang Yu Chi ◽  
Yi Shi ◽  
Xin Chen ◽  
Jian Ma ◽  
Tai Hui Zheng
Keyword(s):  
Heavy Metal ◽  
Structural Changes ◽  
Near Infrared ◽  
Leaf Surface ◽  
Spectral Response ◽  
Spectral Characteristics ◽  
Surface Characteristics ◽  
Heavy Metal Stress ◽  
Metal Stress ◽  
Near Infrared Reflectance

Vegetation which suffers from heavy metal stresses can cause changes of leaf color, shape and structural changes. The spectral characteristics of vegetation leaves is related to leaf thickness, leaf surface characteristics, the content of water, chlorophyll and other pigments. So the eco-physiology changes of plants can be reflected by spectral reflectance. Studies on the spectral response of vegetation to heavy metal stress can provide a theoretical basis for remote sensing monitoring of metal pollution in soils. In recent decades, there are substantial amounts of literature exploring the effects of heavy metals on vegetation spectra.

scholarly journals Snow dunes and glazed surfaces in Antarctica: new field and remote-sensing data

2002 ◽  
Vol 34 ◽  
pp. 81-88 ◽  
Author(s):  
Massimo Frezzotti ◽  
Stefano Gandolfi ◽  
Floriana La Marca ◽  
Stefano Urbini
Keyword(s):  
Remote Sensing ◽  
Near Infrared ◽  
Accumulation Rate ◽  
Spectral Response ◽  
Remote Sensing Data ◽  
Snow Accumulation ◽  
Remotely Sensed Data ◽  
Surface Mass ◽  
Glazed Surface ◽  
Transverse Dunes

AbstractAs part of the International Trans-Antarctic Scientific Expedition project, the Italian Antarctic Programme undertook two traverses from the Terra Nova station to Talos Dome and to Dome C. Along the traverses, the party carried out several tasks (drilling, glaciological and geophysical exploration). The difference in spectral response between glazed surfaces and snow makes it simple to identify these areas on visible/near-infrared satellite images. Integration of field observation and remotely sensed data allows the description of different mega-morphologic features: wide glazed surfaces, sastrugi glazed surface fields, transverse dunes and megadunes. Topography global positioning system, ground penetrating radar and detailed snow-surface surveys have been carried out, providing new information about the formation and evolution of mega-morphologic features. The extensive presence, (up to 30%) of glazed surface caused by a long hiatus in accumulation, with an accumulation rate of nil or slightly negative, has a significant impact on the surface mass balance of a wide area of the interior part of East Antarctica. The aeolian processes creating these features have important implications for the selection of optimum sites for ice coring, because orographic variations of even a few metres per kilometre have a significant impact on the snow-accumulation process. Remote-sensing surveys of aeolian macro-morphology provide a proven, high-quality method for detailed mapping of the interior of the ice sheet’s prevalent wind direction and could provide a relative indication of wind intensity.

High-detectivity panchromatic photodetectors for the near infrared region based on a dimeric porphyrin small molecule

2018 ◽  
Vol 6 (13) ◽  
pp. 3341-3345 ◽  
Author(s):  
Liangang Xiao ◽  
Song Chen ◽  
Xuebin Chen ◽  
Xiaobin Peng ◽  
Yong Cao ◽  
...  
Keyword(s):  
Small Molecule ◽  
Near Infrared ◽  
Spectral Response ◽  
Infrared Region ◽  
Zero Bias ◽  
Near Infrared Region

A dimeric porphyrin-based photodetector shows a strong spectral response at 1000 nm with a detectivity of 1013Jones at zero bias.

scholarly journals How do changes in warm-phase microphysics affect deep convective clouds?

2017 ◽  
Vol 17 (15) ◽  
pp. 9585-9598 ◽  
Author(s):  
Qian Chen ◽  
Ilan Koren ◽  
Orit Altaratz ◽  
Reuven H. Heiblum ◽  
Guy Dagan ◽  
...  
Keyword(s):  
Rain Rate ◽  
Convective Cloud ◽  
Cloud Fraction ◽  
Marshall Islands ◽  
Cloud System ◽  
Main Question ◽  
Convective Clouds ◽  
Deep Convective Clouds ◽  
Aerosol Effects ◽  
Deep Convective Cloud

Abstract. Understanding aerosol effects on deep convective clouds and the derived effects on the radiation budget and rain patterns can largely contribute to estimations of climate uncertainties. The challenge is difficult in part because key microphysical processes in the mixed and cold phases are still not well understood. For deep convective clouds with a warm base, understanding aerosol effects on the warm processes is extremely important as they set the initial and boundary conditions for the cold processes. Therefore, the focus of this study is the warm phase, which can be better resolved. The main question is: How do aerosol-derived changes in the warm phase affect the properties of deep convective cloud systems? To explore this question, we used a weather research and forecasting (WRF) model with spectral bin microphysics to simulate a deep convective cloud system over the Marshall Islands during the Kwajalein Experiment (KWAJEX). The model results were validated against observations, showing similarities in the vertical profile of radar reflectivity and the surface rain rate. Simulations with larger aerosol loading resulted in a larger total cloud mass, a larger cloud fraction in the upper levels, and a larger frequency of strong updrafts and rain rates. Enlarged mass both below and above the zero temperature level (ZTL) contributed to the increase in cloud total mass (water and ice) in the polluted runs. Increased condensation efficiency of cloud droplets governed the gain in mass below the ZTL, while both enhanced condensational and depositional growth led to increased mass above it. The enhanced mass loading above the ZTL acted to reduce the cloud buoyancy, while the thermal buoyancy (driven by the enhanced latent heat release) increased in the polluted runs. The overall effect showed an increased upward transport (across the ZTL) of liquid water driven by both larger updrafts and larger droplet mobility. These aerosol effects were reflected in the larger ratio between the masses located above and below the ZTL in the polluted runs. When comparing the net mass flux crossing the ZTL in the clean and polluted runs, the difference was small. However, when comparing the upward and downward fluxes separately, the increase in aerosol concentration was seen to dramatically increase the fluxes in both directions, indicating the aerosol amplification effect of the convection and the affected cloud system properties, such as cloud fraction and rain rate.

scholarly journals The characterization of deep convective cloud albedo as a calibration target using MODIS reflectances

2010 ◽  
Author(s):  
David R. Doelling ◽  
Gang Hong ◽  
Dan Morstad ◽  
Rajendra Bhatt ◽  
Arun Gopalan ◽  
...  
Keyword(s):  
Convective Cloud ◽  
Calibration Target ◽  
Cloud Albedo ◽  
Deep Convective Cloud

scholarly journals Applying satellite images to spectral signature development of maize production (Zea mays L.) under colombia’s middle tropics conditions

ENTRAMADO ◽  
2019 ◽  
Vol 15 (2) ◽  
pp. 256-262
Author(s):  
Edier Fernando Ávila Vélez ◽  
Natalia Escobar Escobar ◽  
Carlos Francisco Morantes Choconta
Keyword(s):  
Satellite Images ◽  
Near Infrared ◽  
Spectral Response ◽  
Spectral Signature ◽  
Growth Stages ◽  
Total Production ◽  
Radiometric Calibration ◽  
Maize Crop ◽  
Maize Production ◽  
Production Stages

Maize is currently the world’s second largest crop in terms of production, after wheat and rice. It is the first cereal as for grain yield per hectare and the second, after wheat, regarding total production. Maize has great economic importance worldwide, both as human and/or animal food, and as a source of a large number of industrial products. New digital technologies are allowing greater monitoring of farming production stages. This research developed the spectral signature of maize fields ground covers across different growth stages (2 months, 2.3 months and 4.3 months). Similarly, this research paper proposes the application of a methodology based on four phases: 1. Maize crop georeferencing, 2. Satellite images selection, 3. Radiometric calibration of images 4. Spectral signature development of maize crops. Spectral response or signature of maize crops at visible and near-infrared wavelengths was obtained, indicating significant changes in crops growth. The use of satellite imagery becomes an interesting tool that introduces an approach towards more accurate and controlled monitoring systems in agricultural production.

scholarly journals Mesospheric front observations by the OH airglow imager carried out at Ferraz Station on King George Island, Antarctic Peninsula, in 2011

2018 ◽  
Vol 36 (1) ◽  
pp. 253-264 ◽  
Author(s):  
Gabriel Augusto Giongo ◽  
José Valentin Bageston ◽  
Paulo Prado Batista ◽  
Cristiano Max Wrasse ◽  
Gabriela Dornelles Bittencourt ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Near Infrared ◽  
Middle Atmosphere ◽  
Convective Cloud ◽  
Atmospheric Composition ◽  
Secondary Wave ◽  
King George Island ◽  
Composition And Structure ◽  
Waves And Tides ◽  
Energy And Momentum

Abstract. The main goals of this work are to characterize and investigate the potential wave sources of four mesospheric fronts identified in the hydroxyl near-infrared (OH-NIR) airglow images, obtained with an all-sky airglow imager installed at Comandante Ferraz Antarctic Station (EACF, as per its Portuguese acronym) located on King George Island in the Antarctic Peninsula. We identified and analyzed four mesospheric fronts in 2011 over King George Island. In addition, we investigate the atmospheric background environment between 80 and 100 km altitude and discuss the ducts and propagation conditions for these waves. For that, we used wind data obtained from a meteor radar operated at EACF and temperature data obtained from the TIMED/SABER satellite. The vertical wavenumber squared, m2, was calculated for each of the four waves. Even though no clearly defined duct (indicated by positive values of m2 sandwiched between layers above and below with m2  < 0) was found in any of the events, favorable propagation conditions for horizontal propagation of the fronts were found in three cases. In the fourth case, the wave front did not find any duct support and it appeared to dissipate near the zenith, transferring energy and momentum to the medium and, consequently, accelerating the wind in the wave propagation direction (near to south) above the OH peak (88–92 km). The likely wave sources for these four cases were investigated by using meteorological satellite images and in two cases we could find that strong instabilities were potential sources, i.e., a cyclonic activity and a large convective cloud cell. In the other two cases it was not possible to associate troposphere sources as potential candidates for the generation of such wave fronts observed in the mesosphere and secondary wave sources were attributed to these cases. Keywords. Atmospheric composition and structure (airglow and aurora) – meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

Inline biofilm monitoring based on near-infrared spectroscopy with ultracompact spectrometer technology

NIR news ◽  
2020 ◽  
Vol 31 (7-8) ◽  
pp. 9-13
Author(s):  
Robert Zimmerleiter ◽  
Elisabeth Leiss-Holzinger ◽  
Eva Maria Wagner ◽  
Kathrin Kober-Rychli ◽  
Martin Wagner ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spectral Response ◽  
Principal Component ◽  
Cost Effective ◽  
Sensor Surface ◽  
Chain Reaction ◽  
Microelectromechanical System ◽  
Infrared Spectral ◽  
Infrared Measurement ◽  
Polymerase Chain

In this article, we demonstrate a promising inline near-infrared measurement scheme for 24/7 biofilm monitoring based on cost-effective microelectromechanical system-based spectrometer technology. The shown near-infrared spectral data, acquired at a beer-canning line during a representative time span of 10 days, are analyzed by means of principal component analysis and the performance of the monitoring system and its capability to identify biofilms on its sensor surface are investigated by comparing spectral response with results of offline polymerase chain reaction measurements of smear samples. Correlations between presence of a biofilm and its thickness with scores on PC1 and PC2, respectively, were observed.

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