scholarly journals Internal solitary waves propagation speed estimation in the northern-part of Lombok Strait observed by Sentinel-1 SAR and Himawari-8 images

2021 ◽  
Vol 944 (1) ◽  
pp. 012042
Author(s):  
Chonnaniyah ◽  
I W G A Karang ◽  
T Osawa
Keyword(s):  
Optical Sensors ◽  
Propagation Speed ◽  
High Temporal Resolution ◽  
Speed Estimation ◽  
Remotely Sensed Data ◽  
Tidal Period ◽  
Simple Estimation ◽  
Waves Propagation ◽  
Image Pairs ◽  
Wide Swath

Abstract Remotely sensed data, both Synthetic Aperture Radar (SAR) and optical sensors, significantly contribute to the study and understanding internal solitary wave (ISW) dynamics in the ocean. Pairs of SAR and optical sensors were analyzed to estimate the ISW propagation speed in the northern-part of Lombok Strait. ISW propagation speed estimation used an image from Sentinel-1 SAR and three image pairs of Himawari-8 on 29 October 2018 with a time difference of 409 minutes. Sentinel-1 wide-swath imagery (250 km x 400 km) from two adjacent scenes can provide information on multiple ISW packets evolution in the northern-part of Lombok Strait. ISW propagation speed estimation on Sentinel-1 SAR image using the simple estimation by measuring the interpacket distance and dividing by the semidiurnal tidal period. The high temporal resolution of the optical sensor from Himawari-8 can estimate the ISW propagation speed using two different approaches. ISW propagation speed estimation using the semidiurnal tidal period from Sentinel-1 and Himawari-8 showed almost similar values. Sentinel-1 estimation results are 2.69 m.s−1 (Lombok Strait) and 1.30 m.s−1 (northern-part area), Himawari-8 results are 2.52 m.s−1 (Lombok Strait) and 1.27 m.s−1 (northern-part area). ISW propagation speed variability in the northern-part of the Lombok Strait shown in this study.

Prediction Changes for Nonstationary Multi-Temporal Satellite Images using HMM

2017 ◽  
pp. 387-406
Author(s):  
Ali Ben Abbes ◽  
Imed Riadh Farah
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Satellite Image ◽  
Remotely Sensed ◽  
High Temporal Resolution ◽  
Remotely Sensed Data ◽  
Vegetation Monitoring ◽  
Area Of Interest ◽  
Multi Temporal ◽  
The Difference

Due to the growing advances in their temporal, spatial, and spectral resolutions, remotely sensed data continues to provide tools for a wide variety of environmental applications. This chapter presents the benefits and difficulties of Multi-Temporal Satellite Image (MTSI) for land use. Predicting land use changes using remote sensing is an area of interest that has been attracting increasing attention. Land use analysis from high temporal resolution remotely sensed images is important to promote better decisions for sustainable management land cover. The purpose of this book chapter is to review the background of using Hidden Markov Model (HMM) in land use change prediction, to discuss the difference on modeling using stationary as well as non-stationary data and to provide examples of both case studies (e.g. vegetation monitoring, urban growth).

scholarly journals Peripheral Nerve Ligation Elicits Widespread Alterations in Cortical Sensory Evoked and Spontaneous Activity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Donovan M. Ashby ◽  
Jeffrey LeDue ◽  
Timothy H. Murphy ◽  
Alexander McGirr
Keyword(s):  
Functional Connectivity ◽  
Spontaneous Activity ◽  
Optical Sensors ◽  
Large Scale ◽  
Cortical Activity ◽  
Saphenous Nerve ◽  
High Temporal Resolution ◽  
Peripheral Neuropathies ◽  
Cortical Imaging ◽  
Sensory Evoked

Abstract Peripheral neuropathies result in adaptation in primary sensory and other regions of cortex, and provide a framework for understanding the localized and widespread adaptations that arise from altered sensation. Mesoscale cortical imaging achieves high temporal resolution of activity using optical sensors of neuronal activity to simultaneously image across a wide expanse of cortex and capture this adaptation using sensory-evoked and spontaneous cortical activity. Saphenous nerve ligation in mouse is an animal model of peripheral neuropathy that produces hyperalgesia circumscribed to the hindlimb. We performed saphenous nerve ligation or sham, followed by mesoscale cortical imaging using voltage sensitive dye (VSD) after ten days. We utilized subcutaneous electrical stimulation at multiple stimulus intensities to characterize sensory responses after ligation or sham, and acquired spontaneous activity to characterize functional connectivity and large scale cortical network reorganization. Relative to sham animals, the primary sensory-evoked response to hindlimb stimulation in ligated animals was unaffected in magnitude at all stimulus intensities. However, we observed a diminished propagating wave of cortical activity at lower stimulus intensities in ligated animals after hindlimb, but not forelimb, sensory stimulation. We simultaneously observed a widespread decrease in cortical functional connectivity, where midline association regions appeared most affected. These results are consistent with localized and broad alterations in intracortical connections in response to a peripheral insult, with implications for novel circuit level understanding and intervention for peripheral neuropathies and other conditions affecting sensation.

scholarly journals Accurate three-step algorithm for joint source position and propagation speed estimation

2007 ◽  
Vol 87 (12) ◽  
pp. 3096-3100 ◽  
Author(s):  
Jun Zheng ◽  
Kenneth W.K. Lui ◽  
H.C. So
Keyword(s):  
Propagation Speed ◽  
Speed Estimation ◽  
Source Position ◽  
Step Algorithm

Prediction Changes for Nonstationary Multi-Temporal Satellite Images Using HMM

2019 ◽  
pp. 1178-1197
Author(s):  
Ali Ben Abbes ◽  
Imed Riadh Farah
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Satellite Image ◽  
Remotely Sensed ◽  
High Temporal Resolution ◽  
Remotely Sensed Data ◽  
Vegetation Monitoring ◽  
Area Of Interest ◽  
Multi Temporal ◽  
The Difference

Due to the growing advances in their temporal, spatial, and spectral resolutions, remotely sensed data continues to provide tools for a wide variety of environmental applications. This chapter presents the benefits and difficulties of Multi-Temporal Satellite Image (MTSI) for land use. Predicting land use changes using remote sensing is an area of interest that has been attracting increasing attention. Land use analysis from high temporal resolution remotely sensed images is important to promote better decisions for sustainable management land cover. The purpose of this book chapter is to review the background of using Hidden Markov Model (HMM) in land use change prediction, to discuss the difference on modeling using stationary as well as non-stationary data and to provide examples of both case studies (e.g. vegetation monitoring, urban growth).

scholarly journals Sentinel-2 Data for Land Cover/Use Mapping: A Review

2020 ◽  
Vol 12 (14) ◽  
pp. 2291 ◽  
Author(s):  
Darius Phiri ◽  
Matamyo Simwanda ◽  
Serajis Salekin ◽  
Vincent R. Nyirenda ◽  
Yuji Murayama ◽  
...  
Keyword(s):  
Land Cover ◽  
Spatial Resolution ◽  
Positive Impact ◽  
European Space Agency ◽  
Remotely Sensed ◽  
Support Vector ◽  
High Temporal Resolution ◽  
Free Access ◽  
Remotely Sensed Data ◽  
Sentinel 2

The advancement in satellite remote sensing technology has revolutionised the approaches to monitoring the Earth’s surface. The development of the Copernicus Programme by the European Space Agency (ESA) and the European Union (EU) has contributed to the effective monitoring of the Earth’s surface by producing the Sentinel-2 multispectral products. Sentinel-2 satellites are the second constellation of the ESA Sentinel missions and carry onboard multispectral scanners. The primary objective of the Sentinel-2 mission is to provide high resolution satellite data for land cover/use monitoring, climate change and disaster monitoring, as well as complementing the other satellite missions such as Landsat. Since the launch of Sentinel-2 multispectral instruments in 2015, there have been many studies on land cover/use classification which use Sentinel-2 images. However, no review studies have been dedicated to the application of ESA Sentinel-2 land cover/use monitoring. Therefore, this review focuses on two aspects: (1) assessing the contribution of ESA Sentinel-2 to land cover/use classification, and (2) exploring the performance of Sentinel-2 data in different applications (e.g., forest, urban area and natural hazard monitoring). The present review shows that Sentinel-2 has a positive impact on land cover/use monitoring, specifically in monitoring of crop, forests, urban areas, and water resources. The contemporary high adoption and application of Sentinel-2 can be attributed to the higher spatial resolution (10 m) than other medium spatial resolution images, the high temporal resolution of 5 days and the availability of the red-edge bands with multiple applications. The ability to integrate Sentinel-2 data with other remotely sensed data, as part of data analysis, improves the overall accuracy (OA) when working with Sentinel-2 images. The free access policy drives the increasing use of Sentinel-2 data, especially in developing countries where financial resources for the acquisition of remotely sensed data are limited. The literature also shows that the use of Sentinel-2 data produces high accuracies (>80%) with machine-learning classifiers such as support vector machine (SVM) and Random forest (RF). However, other classifiers such as maximum likelihood analysis are also common. Although Sentinel-2 offers many opportunities for land cover/use classification, there are challenges which include mismatching with Landsat OLI-8 data, a lack of thermal bands, and the differences in spatial resolution among the bands of Sentinel-2. Sentinel-2 data show promise and have the potential to contribute significantly towards land cover/use monitoring.

scholarly journals ASSESSMENT OF CLOUD COVER CHARACTERISTICS OVER CALIBRATION TEST SITES USING MODIS CLOUD MASK PRODUCTS

2019 ◽  
Vol XLII-3/W7 ◽  
pp. 83-86
Author(s):  
H. Yamamoto ◽  
S. Tsuchida
Keyword(s):  
Optical Sensors ◽  
Cloud Cover ◽  
Accurate Method ◽  
Adjacent Area ◽  
Calibration Data ◽  
Radiometric Calibration ◽  
Remotely Sensed Data ◽  
Vicarious Calibration ◽  
Calibration Test ◽  
Cloud Mask

<p><strong>Abstract.</strong> Spaceborne remotely sensed data can provide the spatial, spectral, and temporal coverage for earth monitoring. Radiometric calibration is indispensable for the accurate higher level products derived from satellite optical sensors, and the long-term radiometric calibration has a crucial role. Especially, vicarious calibration is currently the most accurate method to conduct the radiometric calibration of satellite optical sensors. Various organization and projects have been conducting the vicarious calibration experiments for satellite optical sensors. Railroad valley playa is the most popular calibration site, and we have been also acquiring the vicarious calibration data for Terra ASTER there from the past. Recently, RadCalNet (Radiometric Calibration Network) is open to the public, which is an initiative of the CEOS WGCV. Railroad valley is also one of the RadCalNet sites, and our calibration site is located at the adjacent area. Understanding the cloud cover characteristics over calibration test sites is very important for vicarious calibration and automated facilities measurement. This research evaluates the clear sky ratio for Railroad valley playa using Terra an Aqua MODIS cloud mask product (MOD35_L2 and MYD35_L2) since 2000.</p>

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