scholarly journals CALIBRATION OF THE SSOT MISSION USING A VICARIOUS APPROACH BASED ON OBSERVATIONS OVER THE ATACAMA DESERT AND THE GOBABEB RADCALNET STATION

2020 ◽  
Vol V-1-2020 ◽  
pp. 133-140
Author(s):  
C. Barrientos ◽  
J. Estay ◽  
E. Barra ◽  
D. Muñoz
Keyword(s):  
Remote Sensing ◽  
Data Collection ◽  
Disaster Management ◽  
Atacama Desert ◽  
Surface Reflectance ◽  
Radiometric Calibration ◽  
Design Life ◽  
The Absolute ◽  
Satellite Sensor

Abstract. This work presents the results of the absolute radiometric calibration of the sensor on-board the “Sistema Satelital de Observación de la Tierra” (SSOT) using the vicarious approach based on in-situ measurements of surface reflectance and atmospheric retrievals. The SSOT mission, also known as FASat-Charlie, has been successfully operating for almost nine years ‒at the time of writing‒, exceeding its five-year nominal design life and providing multispectral and panchromatic imagery for different applications. The data acquired by SSOT has been used for emergency and disaster management and monitoring, cadastral mapping, urban planning, defense purposes, among other uses. In this paper, some results of the efforts conducting to the exploitation of the SSOT imagery for remote sensing quantitative applications are detailed. The results of the assessment of the radiometric calibration of the satellite sensor, performed in the Atacama Desert, Chile, using the data acquired and made available by the Gobabeb Station of Radiometric Calibration Network (RadCalNet), Namibia, are presented. Additionally, we describe the process for obtaining the absolute gains for the multispectral and panchromatic bands of the SSOT sensor by adapting the reflectance−based approach (Thome et al., 2001). The outputs achieved from the Atacama data collection have generated consistent results and average differences in the order of 3% with respect to the RadCalNet TOA reflectances. The presented results are an example of the benefits of having access to the RadCalNet data and how it increases the opportunity of conducting Cal/Val activities using endorsed calibration sites.

scholarly journals Supplementing Oscat winds with Saral Altika observations for cyclone studies

2014 ◽  
Vol XL-8 ◽  
pp. 1059-1064 ◽  
Author(s):  
K. Niharika ◽  
H. S. V. Usha Sundari ◽  
A. V. V. Prasad ◽  
E. V. S. Sita Kumari ◽  
V. K. Dadhwal ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Life Cycle ◽  
Wind Speed ◽  
Storm Surge ◽  
Disaster Management ◽  
Management Practices ◽  
In Situ Observations ◽  
Remote Sensing Techniques ◽  
Microwave Sensors

Accurate prediction of life cycle of cyclone is very critical to the disaster management practices. Since the cyclones originate over the oceans where in situ observations are limited, we have to resort to the remote sensing techniques. Both optical and microwave sensors help studying the cyclones. While scatterometer provide wind vectors, altimeters can give only wind speed. In this paper we present how altimeter measurements can supplement the scatterometer observations in determining the radius of maximum winds (RMW). Sustained maximum winds, indicator for the intensity of the cyclone, are within the eye wall of a cyclone at a distance of RMW. This parameter is also useful in predicting right time of the storm surge. In this paper we used the wind speed estimations from AltiKa, an altimeter operating at Ka band.

scholarly journals ABSOLUTE RADIOMETRIC CALIBRATION OF THE GÖKTÜRK-2 SATELLITE SENSOR USING TUZ GÖLÜ (LANDNET SITE) FROM NDVI PERSPECTIVE

2016 ◽  
Vol XLI-B1 ◽  
pp. 373-377 ◽  
Author(s):  
Ufuk Sakarya ◽  
İsmail Hakkı Demirhan ◽  
Hüsne Seda Deveci ◽  
Mustafa Teke ◽  
Can Demirkesen ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Hyperspectral Data ◽  
Experimental Comparison ◽  
Landsat 8 ◽  
Radiometric Calibration ◽  
Widespread Application ◽  
Comparison Results ◽  
The Absolute ◽  
Cross Calibration ◽  
Satellite Sensor

TÜBİTAK UZAY has conducted a research study on the use of space-based satellite resources for several aspects of agriculture. Especially, there are two precision agriculture related projects: HASSAS (Widespread application of sustainable precision agriculture practices in Southeastern Anatolia Project Region (GAP) Project) and AKTAR (Smart Agriculture Feasibility Project). The HASSAS project aims to study development of precision agriculture practice in GAP region. Multi-spectral satellite imagery and aerial hyperspectral data along with ground measurements was collected to analyze data in an information system. AKTAR aims to develop models for irrigation, fertilization and spectral signatures of crops in Inner Anatolia. By the end of the project precision agriculture practices to control irrigation, fertilization, pesticide and estimation of crop yield will be developed. Analyzing the phenology of crops using NDVI is critical for the projects. For this reason, absolute radiometric calibration of the Red and NIR bands in space-based satellite sensors is an important issue. The Göktürk-2 satellite is an earth observation satellite which was designed and built in Turkey and was launched in 2012. The Göktürk-2 satellite sensor has a resolution 2.5 meters in panchromatic and 5 meters in R/G/B/NIR bands. The absolute radiometric calibration of the Göktürk-2 satellite sensor was performed via the ground-based measurements - spectra-radiometer, sun photometer, and meteorological station- in Tuz Gölü cal/val site in 2015. In this paper, the first ground-based absolute radiometric calibration results of the Göktürk-2 satellite sensor using Tuz Gölü is demonstrated. The absolute radiometric calibration results of this paper are compared with the published cross-calibration results of the Göktürk-2 satellite sensor utilizing Landsat 8 imagery. According to the experimental comparison results, the Göktürk-2 satellite sensor coefficients for red and NIR bands estimated in this work sustained to agree within 2% of calibration coefficients estimated in the cross-calibration results.

scholarly journals Spectral Field Campaigns: Planning and Data Collection

2020 ◽  
pp. 385-423
Author(s):  
Anna K. Schweiger
Keyword(s):  
Remote Sensing ◽  
Data Collection ◽  
Plant Biodiversity ◽  
Ecological Data ◽  
Project Documentation ◽  
Field Campaigns

AbstractThis chapter focuses on planning field campaigns and data collection relevant to plant biodiversity. Particular emphasis is placed on sampling spectra of plants across scales, from the leaf to the canopy and airborne level, considering the issue of matching ecological data with spectra. The importance of planning is highlighted from the perspective of the long-term sustainability of a project, which includes using and contributing to the development of standards for project documentation and archiving. These issues are critical to biodiversity researchers involved in data collection in situ and via remote sensing (RS).

scholarly journals ABSOLUTE RADIOMETRIC CALIBRATION OF THE GÖKTÜRK-2 SATELLITE SENSOR USING TUZ GÖLÜ (LANDNET SITE) FROM NDVI PERSPECTIVE

2016 ◽  
Vol XLI-B1 ◽  
pp. 373-377 ◽  
Author(s):  
Ufuk Sakarya ◽  
İsmail Hakkı Demirhan ◽  
Hüsne Seda Deveci ◽  
Mustafa Teke ◽  
Can Demirkesen ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Hyperspectral Data ◽  
Experimental Comparison ◽  
Landsat 8 ◽  
Radiometric Calibration ◽  
Widespread Application ◽  
Comparison Results ◽  
The Absolute ◽  
Cross Calibration ◽  
Satellite Sensor

TÜBİTAK UZAY has conducted a research study on the use of space-based satellite resources for several aspects of agriculture. Especially, there are two precision agriculture related projects: HASSAS (Widespread application of sustainable precision agriculture practices in Southeastern Anatolia Project Region (GAP) Project) and AKTAR (Smart Agriculture Feasibility Project). The HASSAS project aims to study development of precision agriculture practice in GAP region. Multi-spectral satellite imagery and aerial hyperspectral data along with ground measurements was collected to analyze data in an information system. AKTAR aims to develop models for irrigation, fertilization and spectral signatures of crops in Inner Anatolia. By the end of the project precision agriculture practices to control irrigation, fertilization, pesticide and estimation of crop yield will be developed. Analyzing the phenology of crops using NDVI is critical for the projects. For this reason, absolute radiometric calibration of the Red and NIR bands in space-based satellite sensors is an important issue. The Göktürk-2 satellite is an earth observation satellite which was designed and built in Turkey and was launched in 2012. The Göktürk-2 satellite sensor has a resolution 2.5 meters in panchromatic and 5 meters in R/G/B/NIR bands. The absolute radiometric calibration of the Göktürk-2 satellite sensor was performed via the ground-based measurements - spectra-radiometer, sun photometer, and meteorological station- in Tuz Gölü cal/val site in 2015. In this paper, the first ground-based absolute radiometric calibration results of the Göktürk-2 satellite sensor using Tuz Gölü is demonstrated. The absolute radiometric calibration results of this paper are compared with the published cross-calibration results of the Göktürk-2 satellite sensor utilizing Landsat 8 imagery. According to the experimental comparison results, the Göktürk-2 satellite sensor coefficients for red and NIR bands estimated in this work sustained to agree within 2% of calibration coefficients estimated in the cross-calibration results.

scholarly journals In situ determination of the remote sensing reflectance: an inter-comparison

Ocean Science ◽  
2012 ◽  
Vol 8 (4) ◽  
pp. 567-586 ◽  
Author(s):  
G. Zibordi ◽  
K. Ruddick ◽  
I. Ansko ◽  
G. Moore ◽  
S. Kratzer ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Sensors ◽  
Optical Systems ◽  
Radiometric Calibration ◽  
Northern Adriatic ◽  
Sensing Applications ◽  
Remote Sensing Reflectance ◽  
Data Products ◽  
Relative Differences

Abstract. Inter-comparison of data products from simultaneous measurements performed with independent systems and methods is a viable approach to assess the consistency of data and additionally to investigate uncertainties. Within such a context the inter-comparison called Assessment of In Situ Radiometric Capabilities for Coastal Water Remote Sensing Applications (ARC) was carried out at the Acqua Alta Oceanographic Tower in the northern Adriatic Sea to explore the accuracy of in situ data products from various in- and above-water optical systems and methods. Measurements were performed under almost ideal conditions, including a stable deployment platform, clear sky, relatively low sun zenith angles and moderately low sea state. Additionally, all optical sensors involved in the experiment were inter-calibrated through absolute radiometric calibration performed with the same standards and methods. Inter-compared data products include spectral water-leaving radiance Lw (λ), above-water downward irradiance Ed(0+,λ) and remote sensing reflectance Rrs(λ). Data products from the various measurement systems/methods were directly compared to those from a single reference system/method. Results for Rrs(λ) indicate spectrally averaged values of relative differences comprised between −1 and +6%, while spectrally averaged values of absolute differences vary from approximately 6% for the above-water systems/methods to 9% for buoy-based systems/methods. The agreement between Rrs(λ) spectral relative differences and estimates of combined uncertainties of the inter-compared systems/methods is noteworthy.

scholarly journals Evaluation of Surface Reflectance Products Based on Optimized 6S Model Using Synchronous In Situ Measurements

2021 ◽  
Vol 14 (1) ◽  
pp. 83
Author(s):  
Xiaocheng Zhou ◽  
Xueping Liu ◽  
Xiaoqin Wang ◽  
Guojin He ◽  
Youshui Zhang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Atmospheric Correction ◽  
Solar Spectrum ◽  
In Situ Measurements ◽  
Landsat 8 ◽  
Surface Reflectance ◽  
Landsat 8 Oli ◽  
Auxiliary Data ◽  
Sentinel 2

Surface reflectance (SR) estimation is the most essential preprocessing step for multi-sensor remote sensing inversion of geophysical parameters. Therefore, accurate and stable atmospheric correction is particularly important, which is the premise and basis of the quantitative application of remote sensing. It can also be used to directly compare different images and sensors. The Landsat-8 Operational Land Imager (OLI) and Sentinel-2 Multi-Spectral Instrument (MSI) surface reflectance products are publicly available and demonstrate high accuracy. However, there is not enough validation using synchronous spectral measurements over China’s land surface. In this study, we utilized Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric products reconstructed by Categorical Boosting (CatBoost) and 30 m ASTER Global Digital Elevation Model (ASTER GDEM) data to adjust the relevant parameters to optimize the Second Simulation of Satellite Signal in the Solar Spectrum (6S) model. The accuracy of surface reflectance products obtained from the optimized 6S model was compared with that of the original 6S model and the most commonly used Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) model. Surface reflectance products were validated and evaluated with synchronous in situ measurements from 16 sites located in five provinces of China: Fujian, Gansu, Jiangxi, Hunan, and Guangdong. Through the indirect and direct validation across two sensors and three methods, it provides evidence that the synchronous measurements have the higher and more reliable validation accuracy. The results of the validation indicated that, for Landsat-8 OLI and Sentinel-2 MSI SR products, the overall root mean square error (RMSE) calculated results of optimized 6S, original 6S and FLAASH across all spectral bands were 0.0295, 0.0378, 0.0345, and 0.0313, 0.0450, 0.0380, respectively. R2 values reached 0.9513, 0.9254, 0.9316 and 0.9377, 0.8822, 0.9122 respectively. Compared with the original 6S model and FLAASH model, the mean percent absolute error (MPAE) of the optimized 6S model was reduced by 32.20% and 15.86% for Landsat-8 OLI, respectively. On the other, for the Sentinel-2 MSI SR product, the MPAE value was reduced by 33.56% and 33.32%. For the two kinds of data, the accuracy of each band was improved to varying extents by the optimized 6S model with the auxiliary data. These findings support the hypothesis that reliable auxiliary data are helpful in reducing the influence of the atmosphere on images and restoring reality as much as is feasible.

scholarly journals In situ determination of the remote sensing reflectance: an inter-comparison

2012 ◽  
Vol 9 (2) ◽  
pp. 787-833 ◽  
Author(s):  
G. Zibordi ◽  
K. Ruddick ◽  
I. Ansko ◽  
G. Moore ◽  
S. Kratzer ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Sensors ◽  
Optical Systems ◽  
Radiometric Calibration ◽  
Northern Adriatic ◽  
Sensing Applications ◽  
Remote Sensing Reflectance ◽  
Data Products ◽  
Relative Differences

Abstract. Inter-comparison of data products from simultaneous measurements performed with independent systems and methods is a viable approach to assess the consistency of products and additionally to investigate uncertainties. Within such a context the inter-comparison called Assessment of In Situ Radiometric Capabilities for Coastal Water Remote Sensing Applications (ARC), was carried out at the Acqua Alta Oceanographic Tower in the Northern Adriatic Sea to explore the accuracy of in situ data products from various in- and above-water optical systems and methods. Measurements were performed under almost ideal conditions including: a stable deployment platform, clear sky, relatively low sun zenith angles and moderately low sea state. Additionally, except for one, all optical sensors involved in the experiment were inter-calibrated through a post-field absolute radiometric calibration performed with the same standards and methods. Inter-compared data products include: spectral water-leaving radiance Lw(λ), above-water downward irradiance Ed (0+,λ) and remote sensing reflectance Rrs(λ). Data products from the various measurement systems/methods were directly compared to those from a single reference system/method. Results for Rrs(λ) indicate spectrally averaged values of relative differences comprised between –1 and +6 %, while spectrally averaged absolute values of relative differences vary from approximately 6 % for the above-water systems/methods to 9 % for buoy-based systems/methods. The agreement between Rrs(λ) spectral relative differences and estimates of combined uncertainties of the inter-compared systems/methods is noteworthy.

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