scholarly journals Simulating optical top-of-atmosphere radiance satellite images over snow-covered rugged terrain

2020 ◽  
Vol 14 (11) ◽  
pp. 3995-4020
Author(s):  
Maxim Lamare ◽  
Marie Dumont ◽  
Ghislain Picard ◽  
Fanny Larue ◽  
François Tuzet ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Satellite Image ◽  
Diffuse Radiation ◽  
Optical Remote Sensing ◽  
Mountainous Regions ◽  
Rugged Terrain ◽  
Visible Wavelengths ◽  
The Individual ◽  
New Formulation ◽  
Terrain Features

Abstract. The monitoring of snow-covered surfaces on Earth is largely facilitated by the wealth of satellite data available, with increasing spatial resolution and temporal coverage over the last few years. Yet to date, retrievals of snow physical properties still remain complicated in mountainous areas, owing to the complex interactions of solar radiation with terrain features such as multiple scattering between slopes, exacerbated over bright surfaces. Existing physically based models of solar radiation across rough scenes are either too complex and resource-demanding for the implementation of systematic satellite image processing, not designed for highly reflective surfaces such as snow, or tied to a specific satellite sensor. This study proposes a new formulation, combining a forward model of solar radiation over rugged terrain with dedicated snow optics into a flexible multi-sensor tool that bridges a gap in the optical remote sensing of snow-covered surfaces in mountainous regions. The model presented here allows one to perform rapid calculations over large snow-covered areas. Good results are obtained even for extreme cases, such as steep shadowed slopes or, on the contrary, strongly illuminated sun-facing slopes. Simulations of Sentinel-3 OLCI (Ocean and Land Colour Instrument) scenes performed over a mountainous region in the French Alps allow us to reduce the bias by up to a factor of 6 in the visible wavelengths compared to methods that account for slope inclination only. Furthermore, the study underlines the contribution of the individual fluxes to the total top-of-atmosphere radiance, highlighting the importance of reflected radiation from surrounding slopes which, in midwinter after a recent snowfall (13 February 2018), accounts on average for 7 % of the signal at 400 nm and 16 % at 1020 nm (on 13 February 2018), as well as of coupled diffuse radiation scattered by the neighbourhood, which contributes to 18 % at 400 nm and 4 % at 1020 nm. Given the importance of these contributions, accounting for slopes and reflected radiation between terrain features is a requirement for improving the accuracy of satellite retrievals of snow properties over snow-covered rugged terrain. The forward formulation presented here is the first step towards this goal, paving the way for future retrievals.

scholarly journals Simulating Optical Top-Of-Atmosphere Radiance Satellite Images over Snow-Covered Rugged Terrain

2020 ◽  
Author(s):  
Maxim Lamare ◽  
Marie Dumont ◽  
Ghislain Picard ◽  
Fanny Larue ◽  
François Tuzet ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Satellite Image ◽  
Diffuse Radiation ◽  
Optical Remote Sensing ◽  
Mountainous Regions ◽  
Rugged Terrain ◽  
Visible Wavelengths ◽  
The Individual ◽  
New Formulation ◽  
Terrain Features

Abstract. The monitoring of snow-covered surfaces on Earth is largely facilitated by the wealth of satellite data available, with increasing spatial resolution and temporal coverage over the last years. Yet to date, retrievals of snow physical properties still remain complicated in mountainous areas, owing to the complex interactions of solar radiation with terrain features such as multiple scattering between slopes, exacerbated over bright surfaces. Existing physically-based models of solar radiation across rough scenes are either too complex and resource-demanding for the implementation of systematic satellite image processing, not designed for highly reflective surfaces such as snow, or tied to a specific satellite sensor. This study proposes a new formulation, combining a forward model of solar radiation over rugged terrain with dedicated snow optics into a flexible multi-sensor tool that bridges a gap in the optical remote sensing of snow-covered surfaces in mountainous regions. The model presented here allows to perform rapid calculations over large snow-covered areas. Good results are obtained even for extreme cases, such as steep shadowed slopes or on the contrary, strongly illuminated sun-facing slopes. Simulations of Sentinel-3 OLCI scenes performed over a mountainous region in the French Alps allow to reduce the bias by up to a factor 6 in the visible wavelengths compared to methods that account for slope inclination only. Furthermore, the study underlines the contribution of the individual fluxes to the total top-of-atmosphere radiance, highlighting the importance of reflected radiation from surrounding slopes which, in mid-winter after a recent snowfall (13 February 2018), account on average for 7 % of the signal at 400 nm and 16 % at 1020 nm, as well as coupled diffuse radiation scattered by the neighbourhood, that contributes to 18 % at 400 nm and 4 % at 1020 nm. Given the importance of these contributions, accounting for slopes and reflected radiation between terrain features is a requirement for improving the accuracy of satellite retrievals of snow properties over snow-covered rugged terrain. The forward formulation presented here is the first step toward this goal, paving the way for future retrievals.

Random Forest (RF) and Artificial Neural Network (ANN) Algorithms for LULC Mapping

2020 ◽  
Vol 38 (4A) ◽  
pp. 510-514
Author(s):  
Tay H. Shihab ◽  
Amjed N. Al-Hameedawi ◽  
Ammar M. Hamza
Keyword(s):  
Neural Network ◽  
Remote Sensing ◽  
Artificial Neural Network ◽  
Random Forest ◽  
Satellite Image ◽  
Landsat 8 ◽  
Optical Remote Sensing ◽  
Data Set ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

In this paper to make use of complementary potential in the mapping of LULC spatial data is acquired from LandSat 8 OLI sensor images are taken in 2019.  They have been rectified, enhanced and then classified according to Random forest (RF) and artificial neural network (ANN) methods. Optical remote sensing images have been used to get information on the status of LULC classification, and extraction details. The classification of both satellite image types is used to extract features and to analyse LULC of the study area. The results of the classification showed that the artificial neural network method outperforms the random forest method. The required image processing has been made for Optical Remote Sensing Data to be used in LULC mapping, include the geometric correction, Image Enhancements, The overall accuracy when using the ANN methods 0.91 and the kappa accuracy was found 0.89 for the training data set. While the overall accuracy and the kappa accuracy of the test dataset were found 0.89 and 0.87 respectively.

Improved Accuracy Models For Hourly Diffuse Solar Radiation

2005 ◽  
Vol 128 (1) ◽  
pp. 104-117 ◽  
Author(s):  
T. Muneer ◽  
S. Munawwar
Keyword(s):  
Solar Radiation ◽  
Regression Models ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Evaluation Procedure ◽  
Accuracy Score ◽  
Error Statistics ◽  
Diffuse Solar Radiation ◽  
Energy Applications ◽  
Extensive Evaluation

Solar energy applications require readily available, site-oriented, and long-term solar data. However, the frequent unavailability of diffuse irradiation, in contrast to its need, has led to the evolution of various regression models to predict it from the more commonly available data. Estimating the diffuse component from global radiation is one such technique. The present work focuses on improvement in the accuracy of the models for predicting horizontal diffuse irradiation using hourly solar radiation database from nine sites across the globe. The influence of sunshine fraction, cloud cover, and air mass on estimation of diffuse radiation is investigated. Inclusion of these along with hourly clearness index, leads to the development of a series of models for each site. Estimated values of hourly diffuse radiation are compared with measured values in terms of error statistics and indicators like, R2, mean bias deviation, root mean square deviation, skewness, and kurtosis. A new method called “the accuracy score system” is devised to assess the effect on accuracy with subsequent addition of each parameter and increase in complexity of equation. After an extensive evaluation procedure, extricate but adequate models are recommended as optimum for each of the nine sites. These models were found to be site dependent but the model types were fairly consistent for neighboring stations or locations with similar climates. Also, this study reveals a significant improvement from the conventional k-kt regression models to the presently proposed models.

scholarly journals Estimation of above-ground phytomass and carbon in tree resources outside the forest (TROF): A geo-spatial approach

2015 ◽  
Vol 24 (1) ◽  
pp. 34-40 ◽  
Author(s):  
B. P. Heyojoo ◽  
S. Nandy
Keyword(s):  
Satellite Image ◽  
Uttar Pradesh ◽  
Individual Species ◽  
Individual Tree ◽  
Spatial Approach ◽  
Specific Standard ◽  
Vegetation Carbon ◽  
Carbon Project ◽  
The Individual ◽  
Species Specific

This study aims to estimate above-ground phytomass and carbon of TROF ecosystem in part of Bijnor district in Uttar Pradesh state of India using IRS P6 LISS-IV satellite image by geo-spatial approach coupled with field sampling. Chacko’s formula was referred to compute number of samples in each TROF types and the sample plot size in each stratum was adopted from Vegetation Carbon Project (VCP) under National Carbon Project (NCP). With the help of field data consisting mainly the height and girth information, volume of each individual tree per plot was obtained using site and tree species-specific standard volumetric equations. The phytomass was calculated by multiplying volume with Biomass Expansion Factor (BEF) then with regional specific gravity of the individual species and summed up in each plot to get total phytomass per plot. The total phytomass per plot was reported to be maximum 544.00 t/ha for linear TROF followed by 121.89 t/ha for block TROF. The carbon from phytomass was obtained by multiplying the total phytomass by a conversion factor that represents the average carbon content in phytomass. Spectral modeling for phytomass with different bands and indices were established and the best fit curve (R2 = 0.552) with red band was applied to generate phytomass and carbon distribution map of the study area.Banko Janakari, Vol. 24, No. 1, pp. 34-40

scholarly journals Influence of planning decisions on the local climate of residential building of the Krasnodar region and the Primorsk region

Vestnik MGSU ◽  
2019 ◽  
pp. 954-966 ◽  
Author(s):  
Bleil de Souza Clarice ◽  
Faridun F. Fayzullaev ◽  
Ilya V. Dunichkin
Keyword(s):  
Solar Radiation ◽  
Climatic Factors ◽  
Scientific Research ◽  
Residential Building ◽  
Theory Of Constraints ◽  
Published Data ◽  
Strong Wind ◽  
Wind Rose ◽  
Regulatory Documents ◽  
Terrain Features

Introduction: the article presents the examples of architectural and planning solutions on optimization of courtyard spaces in the southern regions of the Russian Federation, their protection from strong wind, insufficient airing, overheating and solar radiation, as well as anthropogenic and natural ones. In modern Russian construction, insufficient attention is paid to natural and climatic effects. Typical residential housing is used in all regions of the country. The main reason is the lack of regulatory documents for each region, which has its characteristics (presence of water bodies, terrain features, a wind rose, etc.). This problem dictates the need to structure the vital natural and climatic factors which affect the yard territory microclimate. Based on this, compensatory effective improvement methods and solutions that can balance the adverse effect of natural and climatic conditions and create the parameters and norms of architectural and urban planning design are presented. Materials and methods: the article analyzed the following information: standards, guidelines, design and regulatory documents in the field of construction and design, published data, and materials of domestic and foreign scientific research on this subject. Methods of scientific research are based on the use of factor and comparative analyses and the theory of constraints. Results: the article as formed the architectural and planning proposals on the residential area climate-based development. Conclusions: a planning structure based on local natural and climatic consideration (terrain features, the wind rose, etc.) and application of effective methods of territory protection from excessive solar radiation and adverse winds can form a favorable microclimate of a residential building for human comfort habitation. Correct assessment of the climatic features allows making bioclimatic protection economically sound and efficient in terms of energy consumption as well as defining favorable architectural and planning solutions.

scholarly journals Optical Remote Sensing

2021 ◽  
pp. 315-344
Author(s):  
Man Sing Wong ◽  
Xiaolin Zhu ◽  
Sawaid Abbas ◽  
Coco Yin Tung Kwok ◽  
Meilian Wang
Keyword(s):  
Remote Sensing ◽  
Image Processing ◽  
Information Extraction ◽  
Urban Areas ◽  
Satellite Image ◽  
Background Information ◽  
Optical Remote Sensing ◽  
Basic Operation ◽  
City Development ◽  
Satellite Image Processing

AbstractApplications of Earth-observational remote sensing are rapidly increasing over urban areas. The latest regime shift from conventional urban development to smart-city development has triggered a rise in smart innovative technologies to complement spatial and temporal information in new urban design models. Remote sensing-based Earth-observations provide critical information to close the gaps between real and virtual models of urban developments. Remote sensing, itself, has rapidly evolved since the launch of the first Earth-observation satellite, Landsat, in 1972. Technological advancements over the years have gradually improved the ground resolution of satellite images, from 80 m in the 1970s to 0.3 m in the 2020s. Apart from the ground resolution, improvements have been made in many other aspects of satellite remote sensing. Also, the method and techniques of information extraction have advanced. However, to understand the latest developments and scope of information extraction, it is important to understand background information and major techniques of image processing. This chapter briefly describes the history of optical remote sensing, the basic operation of satellite image processing, advanced methods of object extraction for modern urban designs, various applications of remote sensing in urban or peri-urban settings, and future satellite missions and directions of urban remote sensing.

scholarly journals Effects of Sunlight Exposure on Grapevine Powdery Mildew Development

2012 ◽  
Vol 102 (9) ◽  
pp. 857-866 ◽  
Author(s):  
Craig N. Austin ◽  
Wayne F. Wilcox
Keyword(s):  
Powdery Mildew ◽  
Solar Radiation ◽  
Controlled Environment ◽  
Disease Development ◽  
Inhibitory Effects ◽  
Grapevine Powdery Mildew ◽  
Individual Experiment ◽  
Hyphal Formation ◽  
The Individual ◽  
Artificial Shading

Natural and artificially induced shade increased grapevine powdery mildew (Erysiphe necator) severity in the vineyard, with foliar disease severity 49 to 75% higher relative to leaves in full sun, depending on the level of natural shading experienced and the individual experiment. Cluster disease severities increased by 20 to 40% relative to those on check vines when ultraviolet (UV) radiation was filtered from sunlight reaching vines in artificial shading experiments. Surface temperatures of leaves in full sunlight averaged 5 to 8°C higher than those in natural shade, and in one experiment, filtering 80% of all wavelengths of solar radiation, including longer wavelengths responsible for heating irradiated tissues, increased disease more than filtering UV alone. In controlled environment experiments, UV-B radiation reduced germination of E. necator conidia and inhibited both colony establishment (hyphal formation and elongation) and maturity (latent period). Inhibitory effects of UV-B radiation were significantly greater at 30°C than at 20 or 25°C. Thus, sunlight appears to inhibit powdery mildew development through at least two mechanisms, i.e., (i) UV radiation's damaging effects on exposed conidia and thalli of the pathogen; and (ii) elevating temperatures of irradiated tissues to a level supraoptimal or inhibitory for pathogen development. Furthermore, these effects are synergistic at temperatures near the upper threshold for disease development.

scholarly journals Detection and Tracking Method of Maritime Moving Targets Based on Geosynchronous Orbit Satellite Optical Images

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1092
Author(s):  
Fengqi Xiao ◽  
Fei Yuan ◽  
En Cheng
Keyword(s):  
Satellite Image ◽  
Image Sequence ◽  
Geosynchronous Orbit ◽  
Optical Remote Sensing ◽  
Large Area ◽  
Tracking Method ◽  
Detection And Tracking ◽  
Orbit Satellite ◽  
Optical Images ◽  
Long Time

The GF-4 geosynchronous orbit satellite can observe a large area for a long time, but the unique characteristics of its optical remote sensing image restrict the detection of maritime targets. This paper proposes a maritime target detection and tracking method for the GF-4 satellite image sequence based on the differences in information between frames in the image sequence. First, a preprocessing method is proposed for the unique characteristics of the image. Then, the ViBe (Visual Background Extractor) algorithm is used to extract the targets in the image sequence. After detection, the DCF-CSR (discriminative correlation filters with channel and spatial reliability) is used as a tracker to track and correlate the detected target to complete the task of predicting and monitoring the targets’ movements. Finally, through the comparative analysis of experiments with several classic methods, the feasibility and effectiveness of this method are verified.

Sign in / Sign up

Export Citation Format

Share Document