scholarly journals Review of synthetic aperture radar frequency, polarization, and incidence angle data for mapping the inundated regions

2018 ◽  
Vol 12 (02) ◽  
pp. 1 ◽  
Keyword(s):  
Synthetic Aperture Radar ◽  
Incidence Angle ◽  
Synthetic Aperture ◽  
Angle Data ◽  
Radar Frequency ◽  
Aperture Radar

Cross-Polarized Synthetic Aperture Radar: A New Potential Measurement Technique for Hurricanes

2012 ◽  
Vol 93 (4) ◽  
pp. 531-541 ◽  
Author(s):  
Biao Zhang ◽  
William Perrie
Keyword(s):  
Wind Speed ◽  
Synthetic Aperture Radar ◽  
Wind Direction ◽  
Incidence Angle ◽  
Microwave Radiometer ◽  
Synthetic Aperture ◽  
Cross Polarization ◽  
Potential Measurement ◽  
Wind Retrievals ◽  
Aperture Radar

We present an empirical C-band Cross-Polarization Ocean (C-2PO) model for wind retrievals from synthetic aperture radar (SAR) data collected by the RADARSAT-2 satellite. The C-2PO model relates normalized radar cross section (NRCS) in cross polarization to wind speed at 10-m height. This wind retrieval model has the characteristic that it is independent of wind direction and radar incidence angle but is quite linear with respect to wind speed. To evaluate the accuracy of the proposed model, winds with a resolution on the scale of 1 km were retrieved from a dual-polarization SAR image of Hurricane Earl on 2 September 2010, using the C-2PO model and compared with CMOD5.N, the newest available C-band geophysical model function (GMF), and validated with collocated airborne stepped-frequency microwave radiometer measurements and National Data Buoy Center data. Results suggest that for winds up to 38 m s−1, C-2PO has a bias of −0.89 m s−1 and a root-meansquare error of 3.23 m s−1 compared to CMOD5.N, which has a bias of −4.14 m s−1 and an rms difference of 6.24 m s−1. Similar results are obtained from Hurricane Ike, comparing wind retrievals from C-2PO and CMOD5.N with H*Wind data. The advantage of C-2PO over CMOD5.N and other GMFs is that it does not need any external wind direction and radar incidence angle inputs. Moreover, in the presently available quad-polarization dataset, C-2PO has the feature that the cross-polarized NRCS linearly increases even for wind speeds up to 26 m s−1 and reproduces the hurricane eye structure well, thereby providing a potential technique for hurricane observations from space.

scholarly journals Monitoring and Detecting Archaeological Features with Multi-Frequency Polarimetric Analysis

2019 ◽  
Vol 12 (1) ◽  
pp. 1 ◽  
Author(s):  
Jolanda Patruno ◽  
Magdalena Fitrzyk ◽  
Jose Manuel Delgado Blasco
Keyword(s):  
Remote Sensing ◽  
Cultural Heritage ◽  
Synthetic Aperture Radar ◽  
Incidence Angle ◽  
Small Dimension ◽  
Synthetic Aperture ◽  
Alos Palsar ◽  
Multi Temporal ◽  
L Band ◽  
Aperture Radar

In remote sensing for archaeology, an unequivocal method capable of automatic detection of archaeological features still does not exists. Applications of Synthetic Aperture Radar (SAR) remote sensing for archaeology mainly focus on high spatial resolution SAR sensors, which allow the recognition of structures of small dimension and give information of the surface topography of sites. In this study we investigated the potential of combined dual and fully polarized SAR data and performed polarimetric multi-frequency and multi-incidence angle analysis of C-band Sentinel-1, L-band Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) and of C-band Radar Satellite-2 (RADARSAT-2) datasets for the detection of surface and subsurface archaeological structures over the United Nations Educational, Scientific and Cultural Organization (UNESCO) site of Gebel Barkal (Sudan). While PALSAR offers a good historical reference, Sentinel-1 time series provide recent and systematic monitoring opportunities. RADARSAT-2 polarimetric data have been specifically acquired in 2012/2013, and have been scheduled to achieve a multi-temporal observation of the archaeological area under study. This work demonstrated how to exploit a complex but significant dataset composed of SAR full polarimetric and dual polarimetric acquisitions, with the purpose of identifying the most suitable earth observation technique for the preservation and identification of archaeological features. The scientific potential of the illustrated analysis fits perfectly with the current delicate needs of cultural heritage; such analysis demonstrates how multi-temporal and multi-data cultural heritage monitoring can be applied not only for documentation purposes, but can be addressed especially to those areas exposed to threats of different nature that require a constant and prompt intervention plans.

scholarly journals PRELIMINARY RESULTS OF ESTIMATING SOIL MOISTURE OVER BARE SOIL USING FULL-POLARIMETRIC ALOS-2 DATA

2016 ◽  
Vol XLII-2/W1 ◽  
pp. 173-176 ◽  
Author(s):  
A. Sekertekin ◽  
A. M. Marangoz ◽  
S. Abdikan ◽  
M. T. Esetlili
Keyword(s):  
Soil Moisture ◽  
Synthetic Aperture Radar ◽  
Imaging System ◽  
Incidence Angle ◽  
Linear Regression Analysis ◽  
Gravimetric Method ◽  
Synthetic Aperture ◽  
Preliminary Results ◽  
Aperture Radar

Synthetic Aperture Radar (SAR) imaging system is one of the most effective way for Earth observation. The aim of this study is to present the preliminary results about estimating soil moisture using L-band Synthetic Aperture Radar (SAR) data. Full-polarimetric (HH, HV, VV, VH) ALOS-2 data, acquired on 22.04.2016 with the incidence angle of 30.4o, were used in the study. Simultaneously with the SAR acquisition, in-situ soil moisture samples over bare agricultural lands were collected and evaluated using gravimetric method. Backscattering coefficients for all polarizations were obtained and linear regression analysis was carried out with in situ moisture measurements. The best correlation coefficient was observed with VV polarization. Cross-polarized backscattering coefficients were not so sensitive to soil moisture content. In the study, it was observed that soil moisture maps can be retrieved with the accuracy about 14% (RMSE).

scholarly journals Extension of Ship Wake Detectability Model for Non-Linear Influences of Parameters Using Satellite Based X-Band Synthetic Aperture Radar

2019 ◽  
Vol 11 (5) ◽  
pp. 563 ◽  
Author(s):  
Björn Tings ◽  
Andrey Pleskachevsky ◽  
Domenico Velotto ◽  
Sven Jacobsen
Keyword(s):  
Synthetic Aperture Radar ◽  
Incidence Angle ◽  
Real Data ◽  
Synthetic Aperture ◽  
Ship Wake ◽  
The Past ◽  
Non Linear ◽  
Ship Wakes ◽  
Influencing Parameters ◽  
Aperture Radar

The physics of the imaging mechanism underlying the emergence of ship wakes in Synthetic Aperture Radar (SAR) images has been studied in the past by many researchers providing a well-understood theory. Therefore, many publications describe how well ship wakes are detectable on SAR under the influence of different environmental conditions like sea state or local wind, ship properties like ship speed or ship heading, and image acquisition parameters like incidence angle or satellite heading. The increased imaging capabilities of current satellite SAR missions facilitate the collection of large datasets of moving vessels. Such a large dataset of high resolution TerraSAR-X acquisitions now enables the quantitative analysis of the previously formulated theory about the detectability of ship wakes using real data. In this paper we propose an extension of our wake detectability model by using a non-linear basis which allows consideration of all the influencing parameters simultaneously. Such an approach provides new insights and a better understanding of the non-linear influence of parameters on the wake detectability and their interdependencies can now be represented. The results show that the non-linear, interdependent influence of the different influencing parameters on the detectability of wakes matches well to the oceanographic expectations published in the past. Also possible applications of the model for the extraction of missing parameters and automatic for wake detection systems are demonstrated.

scholarly journals DETECTION OF SEEPAGE SLICKS IN CANTARELL COMPLEX (GULF OF MEXICO) USING POLARIMETRIC SAR DATA OF RADARSAT-2

2018 ◽  
Vol 36 (2) ◽  
pp. 137
Author(s):  
Sarah Barrón Torres ◽  
Luiz Bevilacqua ◽  
Fernando Pellon de Miranda ◽  
Carlos Henrique Beisl
Keyword(s):  
Gulf Of Mexico ◽  
Synthetic Aperture Radar ◽  
Incidence Angle ◽  
Alpha Angle ◽  
Time Lapse ◽  
Radar Imaging ◽  
Synthetic Aperture ◽  
Mechanism Analysis ◽  
Imaging Geometry ◽  
Aperture Radar

ABSTRACT. The occurrence of oil seeps on the sea surface from active petroleum systems has been extensively documented by radar imaging using SAR (Synthetic Aperture Radar). Polarimetry is consolidating in the oil industry as a sophisticated technique for the study of marine seeps. The Cantarell Complex, located in the Gulf of Mexico, is currently the most prolific natural seep site in the world. This paper aims to add to the discussion on the physical properties of seepage slicks from full polarimetric data (quad-pol) from RADARSAT-2 satellite. The fact that the research was based on two images (ID#02 and ID#04) acquired at the same place and with the same mode of operation but with a time lapse between acquisitions and different incidence angles allowed to evaluate the influence of the imaging geometry on target signatures. To this end, samples of four classes (sea, offshore platform, oil and false targets) were collected. The data of the samples were afterwards shown in graphs and plotted in the classification plan of Cloude & Pottier – entropy (H) vs. alpha angle (¯α) – for backscattering mechanism analysis. Such elements made it possible to certify that (i) the sea is a Bragg-type surface regardless the incidence angle, (ii) platforms have double-bounce scattering, but small incidence angles are inadequate for their characterization, (iii) false targets (associated in ID#02 to regions of little wind) are moderately random/quasi deterministic surfaces, and (iv) oil behaves either as a Bragg (19.0◦–22.7◦ incidence angle range) or as a random/anisotropic surface (33.7◦–36.7◦ incidence angle range). Keywords: H-¯α diagram, incidence angle, radar imaging, marine seeps.RESUMO. A ocorrência de exsudações de óleo na superfície do mar a partir de sistemas petrolíferos ativos vem sendo extensivamente documentada por imageamento utilizando sistemas SAR (Synthetic Aperture Radar). A polarimetria está se consolidando na indústria do petróleo como uma técnica sofisticada para o estudo de seeps marinhos. O Complexo de Cantarell, situado no Golfo do México, é atualmente o local de exsudação natural de óleo mais prolífico do globo terrestre. Este trabalho visou contribuir com a discussão acerca das propriedades físicas de escapes de óleo a partir dos dados polarimétricos completos (quad-pol) do satélite RADARSAT-2. O fato da pesquisa valer-se de duas imagens (ID#02 e ID#04) adquiridas no mesmo local e modo de operação, mas com intervalo entre as aquisições e diferentes ângulos de incidência, possibilitou avaliar a influência da geometria de imageamento na assinatura dos alvos. Com esse propósito, foram geradas amostras de quatro classes (mar, plataforma, óleo e falso alvo), que tiveram os dados posteriormente relacionados em gráficos e no plano de classificação de Cloude & Pottier – entropia (H) vs. ângulo alfa (¯α) – para análise do mecanismo de espalhamento. Tais elementos permitiram atestar que (i) o mar é uma superfície do tipo Bragg independente do ângulo de incidência, (ii) as plataformas têm espalhamento double-bounce, mas baixos ângulos são inadequados para sua caracterização, (iii) falsos alvos (associados em ID#02 a regiões de baixo vento) são superfícies moderadamente aleatórias/quase determinísticas, e (iv) o óleo comporta-se ou como Bragg (19,0◦–22,7◦), ou como uma superfície aleatória/anisotrópica (33,7◦–36,7◦).Palavras-chave: Diagrama H-¯α, ângulo de incidência, imagem de radar, seeps marinhos.

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