scholarly journals A NOVEL INDEX FOR TEMPORAL STABILITY ANALYSIS IN SPACE AND TIME OF SAR-DERIVED SCENES

2020 ◽  
Vol XLIII-B3-2020 ◽  
pp. 1577-1583
Author(s):  
M. E. Molinari ◽  
A. Monti-Guarnieri ◽  
M. Manzoni
Keyword(s):  
United Arab Emirates ◽  
Risk Mitigation ◽  
European Space Agency ◽  
Temporal Stability ◽  
Stability Index ◽  
Mitigation Measures ◽  
Detection Analysis ◽  
Space Agency ◽  
Regular Time ◽  
Sar Imagery

Abstract. Detecting temporal changes is one of the most important applications of satellite sensors. In recent years, the increasing availability of regular time-series of SAR imagery, provided by the Sentinel-1 mission of the European Space Agency (ESA), has drawn increasing attention to these techniques, especially in earth environment monitoring and risk management. Within this paper, a coherent change detection analysis for evaluating the risk due to movements of dunes and sand sheets in desertic areas is proposed. To this purpose, we introduce a novel, coherence-based index, named Temporal Stability Index (TSI), that is suited for characterizing the percentage of stability of a target with time. TSI maps can be generated over areas as wide as hundreds of kilometers, in a short time, and mostly by exploiting available software tools (plus some simple coding). The information provided is complementary to the average of the short-term coherence, here shown. Results of analysis performed on two desertic regions (the United Arab Emirates and Egypt) document the usefulness of TSI for the identification of dune movements and areas subject to sand accumulation, supporting risk mitigation measures.

scholarly journals Multitemporal InSAR Coherence Analysis and Methods for Sand Mitigation

2021 ◽  
Vol 13 (7) ◽  
pp. 1362
Author(s):  
Marco Manzoni ◽  
Monia Elisa Molinari ◽  
Andrea Monti-Guarnieri
Keyword(s):  
United Arab Emirates ◽  
Natural Hazard ◽  
Temporal Stability ◽  
Stability Index ◽  
Synthetic Aperture ◽  
Mitigation Measures ◽  
Coherence Analysis ◽  
Long Time ◽  
Sand Sheets ◽  
Careful Assessment

Dunes and sand sheets motion natural hazard affect many desertic areas worldwide and require careful assessment to develop effective mitigation plans to protect populated sites, infrastructure, and human activities. The study explores the suitability of Synthetic Aperture Radar (SAR) coherent methods to detect desert area instabilities and estimate sand accumulations displacements. The SAR methods have been applied to long time series of images provided by Sentinel-1. Moreover, the research introduces a novel robust index, named Temporal Stability Index, able to characterize the percentage of stability of a target with time. The work reports the experiments performed on the United Arab Emirates (UAE) and Egypt desertic areas and proves the usefulness of SAR coherent methods to support sand mitigation measures.

scholarly journals Spacecraft collision avoidance challenge: Design and results of a machine learning competition

Astrodynamics ◽  
2021 ◽  
Author(s):  
Thomas Uriot ◽  
Dario Izzo ◽  
Luís F. Simões ◽  
Rasit Abay ◽  
Nils Einecke ◽  
...  
Keyword(s):  
Machine Learning ◽  
Collision Avoidance ◽  
Risk Mitigation ◽  
European Space Agency ◽  
Close Approach ◽  
Lessons Learned ◽  
Mitigation Measures ◽  
Collision Risk ◽  
Problem Domain ◽  
Space Agency

AbstractSpacecraft collision avoidance procedures have become an essential part of satellite operations. Complex and constantly updated estimates of the collision risk between orbiting objects inform various operators who can then plan risk mitigation measures. Such measures can be aided by the development of suitable machine learning (ML) models that predict, for example, the evolution of the collision risk over time. In October 2019, in an attempt to study this opportunity, the European Space Agency released a large curated dataset containing information about close approach events in the form of conjunction data messages (CDMs), which was collected from 2015 to 2019. This dataset was used in the Spacecraft Collision Avoidance Challenge, which was an ML competition where participants had to build models to predict the final collision risk between orbiting objects. This paper describes the design and results of the competition and discusses the challenges and lessons learned when applying ML methods to this problem domain.

National Cyber Governance Awareness Policy and Framework

2019 ◽  
Vol 47 (02) ◽  
pp. 70-89
Author(s):  
Hala Bou Alwan
Keyword(s):  
United Arab Emirates ◽  
Cyber Security ◽  
Risk Mitigation ◽  
The United States ◽  
Cyber Attacks ◽  
Mitigation Measures ◽  
Governmental Agencies ◽  
Academic Level ◽  
The World ◽  
Cyber Education

AbstractDespite an ongoing drive by governments and law enforcers around the world to improve the sophistication of their risk mitigation measures, cyber-attacks are continually increasing. A study from Computer Crime and Intellectual Property Section (CCIPS) shows more than 4,000 ransomware attacks occurred daily in 2016. That's a 300 percent increase over 2015, where 1,000 ransomware attacks were seen per day. Cyber criminals are successfully penetrating even the most high-profile companies and governmental agencies. The breach at the NSA was truly alarming and just one recent example of the dire situation the country, and world, face as cybercrime intensifies and the cyber security talent shortage becomes more serious.Accordingly, the purpose of this research is to focus on cyber education at the national, government, and law enforcement level examining the methodology to set the tone from the top ensuring alignment between governments, law enforcers, private sector, and academic level. It also examines the gaps in cyber laws and educational governance initiatives and their impact on efficient execution of cyber policies for various regions of the world with a focus on the United Arab Emirates and the United States of America.Finally, this article recommends policy guidelines and a compliance manual framework for governments and law enforcers to consider ensuring that cyber risks are properly addressed and mitigated in a structured and coherent way.

scholarly journals The Use of SAR Satellite Imagery to Measure Active Layer Moisture Contents in Arctic Alaska

1996 ◽  
Vol 27 (1-2) ◽  
pp. 25-38 ◽  
Author(s):  
D. L. Kane ◽  
L. D. Hinzman ◽  
Haofang Yu ◽  
D. J. Goering
Keyword(s):  
Surface Soil ◽  
European Space Agency ◽  
Data Sets ◽  
Near Surface ◽  
Moisture Contents ◽  
Space Agency ◽  
Arctic Alaska ◽  
Pixel Value ◽  
Sar Imagery ◽  
Measured Moisture Content

Synthetic aperture radar (SAR) has the potential for measuring near surface soil moisture contents for very large areas. The polar orbiting European Remote Sensing satellite (ERS-1) of the European Space Agency (ESA) has onboard an active C-band SAR sensor. We have analyzed SAR imagery over a small research watershed, Imnavait Creek, located in the northern foothills of the Brooks Range in Alaska, U.S.A. This watershed is treeless and completely underlain with permafrost. After geometrically and radiometrically correcting each pixel (25 m by 25 m) in the image, corrected pixel values were correlated with corresponding field moisture contents measured along transects in the watershed for two passes of the satellite. Coefficients of determination, r2, between the corrected pixel value and measured moisture content were 0.49 on June 12, 1993 and 0.53 on August 2, 1993; with the data sets combined the value was 0.50.

Validation of Aeolus aerosol and wind products with sophisticated ground-based instruments in the Northern and Southern Hemisphere

2020 ◽  
Author(s):  
Holger Baars ◽  
Alina Herzog ◽  
Ronny Engelmann ◽  
Johannes Bühl ◽  
Martin Radenz ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Weather Forecasting ◽  
Eastern Mediterranean ◽  
European Space Agency ◽  
Chem Phys ◽  
High Spectral Resolution ◽  
Backscatter Coefficient ◽  
Range Resolution ◽  
Space Agency ◽  
First Results

<p>The European Space Agency (ESA) has launched the Earth Explorer Mission Aeolus on 22 August 2018. Within the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations), Cal/Val activities for Aeolus started immediately after the instrument was turned on in space. The aim is to validate the wind and aerosol products of Aeolus and to quantify the benefits of these new measurements for weather forecasting and aerosol and cloud research. <br>For this purpose, ground-based aerosol and wind lidar observations have been performed at the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany, and at Punta Arenas (53.13 S, 70.88 W), Chile, in the frame of the DACAPO-PESO campaign (dacapo.tropos.de). Radiosondes have been launched during the Aeolus overpasses each Friday at Leipzig in addition since mid of May 2019. In Punta Arenas, we also used Doppler cloud radar observations with respect to the validation of Mie and Rayleigh winds of Aeolus.  </p><p>Aerosol-only observations with multiwavelength-Raman polarization lidar were made at the PollyNET (Baars 2016) stations in Haifa (Israel), Dushanbe (Tajikistan), Tel Aviv (Israel), and in the United Arab Emirates (UAE) - the latter two are hosted by PollyNET partner institutions (Baars, 2016). These locations are close to the desert with frequent dense, lofted aerosol layers and are thus of particular interest for Aeolus Cal/Val. Considering the long averaging length of Aeolus (87 km) and the distance to the lidars (max. 100 km), a good agreement with respect to the co-polar backscatter coefficient is found between Aeolus and the ground-based lidars at these locations.</p><p>We will present results from the above-mentioned Cal/Val activities with respect to, both, wind and aerosol products of Aeolus. It will be shown, that one of the mission goals, namely the demonstration that wind observations from space by active remote sensing are possible, have been already achieved. Furthermore, it will be demonstrated that the spaceborne HSRL (high spectral resolution lidar) technique applied for Aeolus can provide independent backscatter and extinction measurements of aerosols – a spaceborne novelty as well. Since September 2019, also an aerosol-optimized range resolution, the so-called Mediterranean range-bin setting (MARS), is operational for Aeolus in the Eastern Mediterranean. First results show a significantly improved aerosol retrieval for this adapted instrumental setting and will be presented as well.</p><p> </p><p>Reference:</p><p>Baars, H., et al. (2016), An overview of the first decade of PollyNET: An emerging network of automated Raman-polarization lidars for continuous aerosol profiling, Atmos. Chem. Phys., 16(8), 5111-5137, doi:10.5194/acp-16-5111-2016.</p>

scholarly journals Mapping Spatio-Temporal Soil Erosion Patterns in the Candelaro River Basin, Italy, Using the G2 Model with Sentinel2 Imagery

Geosciences ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 89 ◽  
Author(s):  
Christos Karydas ◽  
Ouiza Bouarour ◽  
Pandi Zdruli
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Arable Land ◽  
European Space Agency ◽  
Retention Factor ◽  
Mitigation Measures ◽  
Erosion Rates ◽  
Apulia Region ◽  
Space Agency ◽  
Spatio Temporal

This study aims at mapping soil erosion caused by water in the Candelaro river basin, Apulia region, Italy, using the G2 erosion model. The G2 model can provide erosion maps and statistical figures at month-time intervals, by applying non data-demanding alternatives for the estimation of all the erosion factors. In the current research, G2 is taking a step further with the introduction of Sentinel2 satellite images for mapping vegetation retention factor on a fine scale; Sentinel2 is a ready-to-use, image product of high quality, freely available by the European Space Agency. Although only three recent cloud-free Sentinel2 images covering Candelaro were found in the archive, new solutions were elaborated to overcome time-gaps. The study in Candelaro resulted in a mean annual erosion rate of 0.87 t ha−1 y−1, while the autumn months were indicated to be the most erosive ones, with average erosion rates reaching a maximum of 0.12 t ha−1 in September. The mixed agricultural-natural patterns revealed to be the riskiest surfaces for most months of the year, while arable land was the most extensive erosive land cover category. The erosion maps will allow competent authorities to support relevant mitigation measures. Furthermore, the study in Candelaro can play the role of a pilot study for the whole Apulia region, where erosion studies are rather limited.

scholarly journals Utilization of BEAM and NEST open source toolboxes in education and research

2010 ◽  
Vol 5 ◽  
pp. 37-48
Author(s):  
Markéta Potůčková ◽  
Eva Štefanová
Keyword(s):  
Remote Sensing ◽  
Open Source ◽  
Satellite Images ◽  
European Space Agency ◽  
Radar Data ◽  
Optical Data ◽  
Basic Principles ◽  
Data Formats ◽  
Space Agency ◽  
Sar Imagery

European Space Agency (ESA) provides several open source toolboxes for visualization, processing and analyzing satellite images acquired both in optical and microwave domains. Basic ERS & Envisat (A)ATSR and MERIS Toolbox (BEAM) was originally developed for easier handling ENVISAT optical data. Today this toolbox supports several raster data formats and datasets collected with other EO instruments such as MODIS, AVHRR, CHRIS/Proba. The NEXT ESA SAR Toolbox (NEST) has been created for processing radar data acquired from different satellites such as ERS 1&2, ENVISAT, RADARSAT or TerraSAR X. Both toolboxes are suitable for the education of the basic principles of data processing (geometric and radiometric corrections, classification, filtering of radar data) but also for research. Possibilities for utilization of these toolboxes in remote sensing courses based on two examples of practical exercises are described. Use of the NEST toolbox is demonstrated on a research project dealing with snow cover detection from SAR imagery.

scholarly journals A Monte Carlo Analysis for Collision Risk Assessment on Vega Launcher Payloads and LARES Satellite

2016 ◽  
Vol 51 (1) ◽  
pp. 45-54 ◽  
Author(s):  
G. Sindoni ◽  
I. Ciufolini ◽  
F. Battie
Keyword(s):  
European Space Agency ◽  
Monte Carlo Analysis ◽  
Mitigation Measures ◽  
Additional Contribution ◽  
Collision Risk ◽  
Frame Dragging ◽  
Space Agency ◽  
Last Stage ◽  
Italian Space Agency ◽  
Debris Mitigation

Abstract This work has been developed in the framework of the LARES mission of the Italian Space Agency (ASI). The LARES satellite has been built to test, with high accuracy, the frame–dragging effect predicted by the theory of General Relativity, specifically the Lense–Thirring drag of its node. LARES was the main payload in the qualification flight of the European Space Agency launcher VEGA. A concern arose about the possibility of an impact between the eight secondary payloads among themselves, with LARES and with the last stage of the launcher (AVUM). An impact would have caused failure on the payloads and the production of debris in violation of the space debris mitigation measures established internationally. As an additional contribution, this study allowed the effect of the payload release on the final manoeuvers of the AVUM to be understood.

scholarly journals POTENTIALITIES OF SENTINEL-1 FOR MAPPING AND MONITORING GEOLOGICAL AND CRYOSPHERIC PROCESSES IN THE PATAGONIA REGION (CHILE)

2020 ◽  
Vol IV-3/W2-2020 ◽  
pp. 137-142
Author(s):  
O. Monserrat ◽  
C. Cardenas ◽  
P. Olea ◽  
V. Krishnakumar ◽  
B. Crippa
Keyword(s):  
Urban Areas ◽  
European Space Agency ◽  
Data Distribution ◽  
Free Access ◽  
Natural Processes ◽  
The Past ◽  
Space Agency ◽  
Glacier Dynamics ◽  
Sar Imagery

Abstract. This work shows two examples on the use of Sentinel-1 data for monitoring different natural processes, like active geohazards or glacier dynamics in the Patagonia region. Sentinel-1 is a two-satellite constellation, launched by the European Space Agency (ESA), that provides SAR imagery with interferometric capabilities. It is in operation since 2014 and has supposed a significant improvement in the exploitation of these type of data for applications like natural hazards mapping and monitoring. The acquisition policy, that guarantees an acquisition each few days (12 days in Patagonia region) for both ascending and descending trajectories, and the data distribution policy, that allows free access to the images without legal constrains, are the main reasons for this improvement. These two aspects allowed not only to assure the data in the past but also to perform monitoring plans at medium-long term. In this work we show the potentialities of the use of these data in the Patagonia region through the application of two different techniques in two different application test sites: urban areas and glaciers.

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