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2022 ◽  
Vol 14 (2) ◽  
pp. 407
Author(s):  
Jongjin Seo ◽  
Haklim Choi ◽  
Young-Suk Oh

Aerosols in the atmosphere play an essential role in the radiative transfer process due to their scattering, absorption, and emission. Moreover, they interrupt the retrieval of atmospheric properties from ground-based and satellite remote sensing. Thus, accurate aerosol information needs to be obtained. Herein, we developed an optimal-estimation-based aerosol optical depth (AOD) retrieval algorithm using the hyperspectral infrared downwelling emitted radiance of the Atmospheric Emitted Radiance Interferometer (AERI). The proposed algorithm is based on the phenomena that the thermal infrared radiance measured by a ground-based remote sensor is sensitive to the thermodynamic profile and degree of the turbid aerosol in the atmosphere. To assess the performance of algorithm, AERI observations, measured throughout the day on 21 October 2010 at Anmyeon, South Korea, were used. The derived thermodynamic profiles and AODs were compared with those of the European center for a reanalysis of medium-range weather forecasts version 5 and global atmosphere watch precision-filter radiometer (GAW-PFR), respectively. The radiances simulated with aerosol information were more suitable for the AERI-observed radiance than those without aerosol (i.e., clear sky). The temporal variation trend of the retrieved AOD matched that of GAW-PFR well, although small discrepancies were present at high aerosol concentrations. This provides a potential possibility for the retrieval of nighttime AOD.


2021 ◽  
Vol 13 (1) ◽  
pp. 149-174
Author(s):  
Juan Vitar ◽  
Karen X. Sandoval Parra ◽  
Martha L. Ortiz Moreno

Contextualization: Colombia has experienced multiple land-cover changes derived from socio-economic policies that have reduced the high biodiversity of the country.  Knowledge gap: In the Orinoquía region, the pressure to expand the agricultural frontier is increasing, without considering the importance of its natural resources.  Purpose: This paper aimed to analyze the land-cover variations associated with agricultural practices, in the department of Vichada, with a special interest in vulnerable ecosystems, such as the Bita’s river basin, using Geographic Information System [GIS] analysis of historical images taken by a remote sensor from the United States Geological Service [USGS] Earth Explorer portal.  Methodology:  Documental review and an analysis of satellite images from 1985 to 2017.  Results and conclusions: The results showed that in Vichada, during a 32-year period, there was a transition from forest to cropland and pastures, in which 60% of the forest cover got lost. Moreover, areas of natural savannas were also replaced with pastures for livestock production. These land-cover changes were associated with government policies that fomented illegal occupation of land, monocultures, and non-native plantation forests. Bita’s river basin also lost a significant part of forest cover because of agribusiness development in the municipality of Puerto Carreño (Vichada). These land-cover changes have an impact on the ecological integrity of significant ecosystems and in their functionality in the region, that is why, conservation measures must be implemented.  


2021 ◽  
Vol 13 (24) ◽  
pp. 4996
Author(s):  
Lingling Ma ◽  
Yongguang Zhao ◽  
Chuanrong Li ◽  
Philippe Goryl ◽  
Cheng Liu ◽  
...  

Robust calibration and validation (Cal and Val) should guarantee the accuracy of the retrieved information, make the remote sensing data consistent and traceable, and maintain the sensor performance during the operational phase. The DRAGON program has set up many remote sensing research topics on various application domains. In order to promote the effectiveness of data modeling and interpretation, it is necessary to solve various challenges in Cal and Val for quantitative RS applications. This project in the DRAGON 4 program aims to promote the cooperation of the Cal and Val experts from European and Chinese institutes in Cal and Val activities, and several achievements have been obtained in the advanced on-orbit optical sensor calibration, as well as microwave remote sensor calibration and product generation. The outcomes of the project have benefited the related remote sensing modeling and product retrieval, and promoted the radiometric calibration network (RadCalNet) as an international operational network for calibration, intercalibration, and validation. Moreover, this project provided local governments with a more accurate OMI NO2 data in China, which were used to study the air quality control during APEC period, Parade period and G20 period. This will be of ongoing be value for monitoring atmospheric environmental quality and formulating pollution control strategies.


Author(s):  
Ms. Priyanka Mamde

Abstract: In this paper, we propose fostering a framework ideally watering horticultural harvests dependent on a remote sensor organization. This work planned to plan and foster a control framework utilizing hub sensors in the harvest field with information the executives by means of cell phone and a web application. The three parts are equipment, web application, and portable application. The principal segment was planned and executed in charge box equipment associated with gather information on the harvests. Soil dampness sensors are utilized to screen the field, associating with the control box. The subsequent segment is an electronic application that was planned and executed to control the subtleties of yield information and field data. This segment applied information mining to break down the information for anticipating appropriate temperature, stickiness, and soil dampness for ideal future administration of harvests development. The last part is essentially used to control crop watering through a versatile application in a cell phone. This permits either programmed or manual control by the client. The programmed control utilizes information from soil dampness sensors for watering. Be that as it may, the client can pick manual control of watering the harvests in the useful control mode. The framework can send notices through LINE API for the LINE application. The framework was executed and tried in Makhamtia District, Suratthani Province, Thailand. The outcomes demonstrated the execution to be valuable in agribusiness. The dampness content of the dirt was kept up with properly for vegetable development, lessening costs and expanding rural usefulness. Also, this work addresses driving farming through computerized development.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tian J. Ma

AbstractBig Data in the area of Remote Sensing has been growing rapidly. Remote sensors are used in surveillance, security, traffic, environmental monitoring, and autonomous sensing. Real-time detection of small moving targets using a remote sensor is an ongoing, challenging problem. Since the object is located far away from the sensor, the object often appears too small. The object’s signal-to-noise-ratio (SNR) is often very low. Occurrences such as camera motion, moving backgrounds (e.g., rustling leaves), low contrast and resolution of foreground objects makes it difficult to segment out the targeted moving objects of interest. Due to the limited appearance of the target, it is tough to obtain the target’s characteristics such as its shape and texture. Without these characteristics, filtering out false detections can be a difficult task. Detecting these targets, would often require the detector to operate under a low detection threshold. However, lowering the detection threshold could lead to an increase of false alarms. In this paper, the author will introduce a new method that improves the probability to detect low SNR objects, while decreasing the number of false alarms as compared to using the traditional baseline detection technique.


2021 ◽  
Vol 13 (19) ◽  
pp. 3808
Author(s):  
Xavier Pons ◽  
Joan-Cristian Padró

This study focuses on the recovery of information from shadowed pixels in RGB or multispectral imagery sensed from unmanned aerial vehicles (UAVs). The proposed technique is based on the concept that a property characterizing a given surface is its spectral reflectance, i.e., the ratio between the flux reflected by the surface and the radiant flux received by the surface, and this ratio is usually similar under direct-plus-diffuse irradiance and under diffuse irradiance when a Lambertian behavior can be assumed. Scene-dependent elements, such as trees, shrubs, man-made constructions, or terrain relief, can block part of the direct irradiance (usually sunbeams), in which part of the surface only receives diffuse irradiance. As a consequence, shadowed surfaces comprising pixels of the image created by the UAV remote sensor appear. Regardless of whether the imagery is analyzed by means of photointerpretation or digital classification methods, when the objective is to create land cover maps, it is hard to treat these areas in a coherent way in terms of the areas receiving direct and diffuse irradiance. The hypothesis of the present work is that the relationship between irradiance conditions in shadowed areas and non-shadowed areas can be determined by following classical empirical line techniques for fulfilling the objective of a coherent treatment in both kinds of areas. The novelty of the presented method relies on the simultaneous recovery of information in non-shadowed and shadowed areas by the in situ spectral reflectance measurements of characterized Lambertian targets followed by smoothing of the penumbra area. Once in the lab, firstly, we accurately detected the shadowed pixels by combining two well-known techniques for the detection of the shadowed areas: (1) using a physical approach based on the sun’s position and the digital surface model of the area covered by the imagery; and (2) the image-based approach using the histogram properties of the intensity image. In this paper, we present the benefits of the combined usage of both techniques. Secondly, we applied a fit between non-shadowed and shadowed areas by using a twin set of spectrally characterized target sets. One set was placed under direct and diffuse irradiance (non-shadowed targets), whereas the second set (with the same spectral characteristics) was placed under diffuse irradiance (shadowed targets). Assuming that the reflectance of the homologous targets of each set was the same, we approximated the diffuse incoming irradiance through an empirical line correction. The model was applied to all detected shadowed areas in the whole scene. Finally, a smoothing filter was applied to the penumbra transitions. The presented empirical method allowed the operational and coherent recovery of information from shadowed areas, which is very common in high-resolution UAV imagery.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mark Cooper ◽  
Carlos D. Messina

The diverse consequences of genotype-by-environment (GxE) interactions determine trait phenotypes across levels of biological organization for crops, challenging our ambition to predict trait phenotypes from genomic information alone. GxE interactions have many implications for optimizing both genetic gain through plant breeding and crop productivity through on-farm agronomic management. Advances in genomics technologies have provided many suitable predictors for the genotype dimension of GxE interactions. Emerging advances in high-throughput proximal and remote sensor technologies have stimulated the development of “enviromics” as a community of practice, which has the potential to provide suitable predictors for the environment dimension of GxE interactions. Recently, several bespoke examples have emerged demonstrating the nascent potential for enhancing the prediction of yield and other complex trait phenotypes of crop plants through including effects of GxE interactions within prediction models. These encouraging results motivate the development of new prediction methods to accelerate crop improvement. If we can automate methods to identify and harness suitable sets of coordinated genotypic and environmental predictors, this will open new opportunities to upscale and operationalize prediction of the consequences of GxE interactions. This would provide a foundation for accelerating crop improvement through integrating the contributions of both breeding and agronomy. Here we draw on our experience from improvement of maize productivity for the range of water-driven environments across the US corn-belt. We provide perspectives from the maize case study to prioritize promising opportunities to further develop and automate “enviromics” methodologies to accelerate crop improvement through integrated breeding and agronomic approaches for a wider range of crops and environmental targets.


Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5919
Author(s):  
Mingqiang Zhang ◽  
Yaobin Li ◽  
Yalin Ding ◽  
Jianjun Sun ◽  
Jing Li

In order to reduce the influence of the optical window on the image quality of a hypersonic visible light optical remote sensor, we propose a method of adding a double-layer semicircular honeycomb core microstructure with flexible support of a high temperature elastic alloy between a window glass and a frame to reduce the influence of complex thermal stress on the surface accuracy of the optical window. An equivalent model of a semicircular honeycomb structure was established, the elastic parameters of the semicircular honeycomb sandwich microstructure were derived by an analytical method, and a numerical verification and finite element simulation were carried out. The results show that the equivalent model is in good agreement with the detailed model. The optical-mechanical-thermal integrated simulation analysis of the optical window assembly with flexible supporting microstructure proves that the semicircular honeycomb sandwich flexible supporting structure has a positive effect on stress attenuation of the window glass and ensures the wave aberration accuracy of the transmitted optical path difference of the optical window (PV < 0.665 λ, RMS < 0.156 λ, λ = 632.8 nm). Combined with the actual optical system, the optical performance of the window assembly under the flexible support structure is verified. The simulation results show that the spatial frequency of the modulation transfer function (MTF) of the optical system after focusing is not less than 0.58 in the range of 0–63 cycle/mm and the relative decline of MTF is not more than 0.01, which meet the imaging requirements of a remote sensor. The study results show that the proposed metal-based double-layer semicircular honeycomb sandwich flexible support microstructure ensures the imaging quality of the optical window under ultra-high temperature conditions.


Author(s):  
Hang Li ◽  
WenKang Liu ◽  
GuangCai Sun ◽  
MengDao Xing ◽  
ZhenHua Zhang ◽  
...  

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