Journal articles: 'Polarimetrie'

1

Dimitrov, Zlatomir. "Polarimetric Analysis of ALOS PALSAR data (POL-SAR) over Test Areas in North-West Bulgaria – Polarimetric Descriptors, Decompositions and Classifications." Aerospace Research in Bulgaria 34 (2022): 29–55. http://dx.doi.org/10.3897/arb.v34.e03.

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This study is focused on utilizing full-polarimetric L-band radar data from ALOS PALSAR (JAXA) by means of Polarimetry (POL-SAR), over mountainous test sites in Bulgaria. General aim is to show feasibility of the Polarimetry to describe natural targets, which exhibits various scattering mechanisms in respect to their bio-physical and geometrical properties. Firstly, the importance of Covariance and Coherent matrices is shown, which is followed by calculation of the polarimetric coherences with their particular significance. The mathematical and physical model based decompositions are applied to describe backscattering media from scattering mechanisms. Radar indices resulted from H/A/α-decomposition showed radnomization of scattering mechanisms over forest areas, whilst two major scattering mechanisms are observed mainly in crop lands. Α comparison is made between polarimetric descriptors from acquisitions in different seasonality over mountainous forest and agricultural lands. Polarimetric segmentations and classifications are applied, with 8 (H/A) and 16 (H/A/α) components. Finally, a forest mask is proposed based on relevant polarimetric descriptors. Study showed good utilization and importance of the full-polarimetric L-band SAR data, derived from ALOS PALSAR, in natural targets and forest areas. This report resulted from a course GEO414 -“Polarimetrie”, held at the University of Jena, Lehrstuhl für Fernerkundung, in the framework of ERASMUS+, with the kind support of – Dr. T. Jagdhuber (DLR) and Prof. C. Schmullius.

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Kalina, Jiří, and Michal Lach. "Experiment for "Polarimetry" Teaching." Chemické listy 117, no. 1 (January 15, 2023): 30–36. http://dx.doi.org/10.54779/chl20230030.

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Polarimetry enables one to quantitatively determine certain substance (optically active substances) in a solution on the basis of rotation of the plane of the polarized light of a single wavelength. The main goal of this work is to measure concentration of optically active substances using homemade device, so called "polarimeter". The device measures the degree of light attenuation instead of the polarization angle of the polarized light as in commercial instruments. The designed "polarimeter" allows one to determine the concentration of optically active substances. It is a home-made device using a smartphone with a selected software, which is many times cheaper than commercially available ones. The authors would like to see the device find use in polytechnic education of students. Polarimetrie umožňuje kvantitativně stanovit určitou látku (opticky aktivní látky) v roztoku na základě měření úhlu stočení roviny polarizovaného světla jedné vlnové délky. Hlavním cílem této práce je měření koncentrace opticky aktivních látek pomocí podomácku vyrobeného přístroje, tzv. „polarimetru“. Zařízení měří míru zeslabení světla namísto úhlu stočení polarizovaného světla jako u komerčních přístrojů. Navržený „polarimetr“ umožňuje stanovit koncentraci opticky aktivních látek. Jde o podomácku vyrobené zařízení využívající chytrý telefon s vybraným softwarem, který je mnohonásobně levnější než komerčně dostupné. Autoři by rádi viděli využití zařízení v polytechnické výchově studentů.

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Sterken, C., A. U. Landolt, M. Beaseli, M. Breger, I. Glass, J. Graham, H. Hensberge, et al. "Commission 25: Stellar Photometry and Polarimetry: (Photometrie et Polarimetrie Stellaire)." Transactions of the International Astronomical Union 24, no. 1 (2000): 328–35. http://dx.doi.org/10.1017/s0251107x00003278.

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The work of Commission 25 covers a wide range of topics concerning the measurement of magnitude, colour and polarisation of astronomical objects. As such, the area of interest covers virtually every field of astrophysical research in the visual and infrared spectral domain. Our reports cover some aspects of photometry and polarimetry as a technique rather than being an account of research highlights over the last three years.

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Rufener, F. G., I. S. McLean, R. Buser, J. Dachs, P. J. Edwards, I. S. Glass, D. Kilkenny, et al. "Commission 25. Stellar Photometry and Polarimetry Photometrie Et Polarimetrie Stellaires." Transactions of the International Astronomical Union 20, no. 1 (1988): 243–52. http://dx.doi.org/10.1017/s0251107x00007173.

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The outstanding feature of the last triennium was most certainly the abrupt generalisation of the use of array detectors, particularly CCDs (charge coupled devices). The latter pervade all subdivisions of instrumental astronomy. The gains achieved by their high quantum efficiency, their stability, their capability of delivering immediately recordable signals which can be processed by appropriate computational means, have been the cause of spectacular progress regarding the photometric precision of weak signal measurements.

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McLean, I. S. "Commission 25. Stellar Photometry and Polarimetry Photometrie Et Polarimetrie Stellaires." Transactions of the International Astronomical Union 21, no. 1 (1991): 235–42. http://dx.doi.org/10.1017/s0251107x00010063.

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Technology has continued to influence the methods of stellar photometry and polarimetry in the last triennium. For example, CCDs continue to displace photographic plates in stellar photometry and other detector systems for imaging and spectro-polarimetry, new array detectors for infrared wavelengths have revolutionised the way infrared photometry and polarimetry is done and small automatic telescopes and robotic observatories have experienced a remarkable growth period. The volume of data to be archived and transformed to “standard” systems has become immense and all the problems of inter-comparing different systems still remain.

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Sterken, C. "Commission 25: Stellar Photometry and Polarimetry (Photometrie Stellaire Et Polarimetrie)." Transactions of the International Astronomical Union 25, no. 2 (2007): 181–83. http://dx.doi.org/10.1017/s0251107x00026791.

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Sterken, C., A. Landolt, S. Adelman, P. Bastien, M. Bessell, S. Fabrika, R. Gilliland, et al. "Commission 25: Stellar Photometry and Polarimetry: (Photometrie Et Polarimetrie Stellaires)." Transactions of the International Astronomical Union 25, no. 1 (2002): 338–39. http://dx.doi.org/10.1017/s0251107x00001693.

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McLean, I. S., A. T. Young, and F. Rufener. "Commission No. 25: Stellar Photography and Polarimetry (Photometrie et Polarimetrie Stellaire)." Transactions of the International Astronomical Union 20, no. 2 (1988): 223–31. http://dx.doi.org/10.1017/s0251107x00027449.

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9

Hoffmann, E. M., and A. Schulze. "Glaukomdiagnostik mittels Scanning-Laser-Polarimetrie." Der Ophthalmologe 106, no. 8 (August 2009): 696–701. http://dx.doi.org/10.1007/s00347-009-1956-7.

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10

Sens, Frank-Michael, Daniel Mojon, Johannes Fleischhauer, Oliver Bergamin, and Matthias Bohnke. "Nervenfaserschichtdickenmessung mittels Laser-Scanning-Polarimetrie im Altersvergleich." Klinische Monatsblätter für Augenheilkunde 212, no. 05 (May 1998): 261–63. http://dx.doi.org/10.1055/s-2008-1034875.

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11

Iodice, Antonio, Antonio Natale, and Daniele Riccio. "An SPM/PO-based Polarimetrie Two-Scale Model." European Journal of Remote Sensing 45, no. 1 (January 2012): 167–76. http://dx.doi.org/10.5721/eujrs20124516.

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12

Kremmer, S., G. Anastassiou, and J. Selbach. "Stellenwert der Scanning Laser Polarimetrie für die Glaukomdiagnostik." Klinische Monatsblätter für Augenheilkunde 229, no. 02 (February 2012): 126–34. http://dx.doi.org/10.1055/s-0031-1299246.

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De Biasio, Francesco, and Stefano Zecchetto. "Towards the wind direction determination in RADARSAT-2 polarimetrie images." European Journal of Remote Sensing 45, no. 1 (January 2012): 141–51. http://dx.doi.org/10.5721/eujrs20124514.

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Rohrschneider, Klaus, Reinhard Burk, Friedrich Kruse, and Hans Völcker. "Zur Bestimmung der retinalen Nervenfaserschichtdicke in vivo mittels Laser-Polarimetrie." Klinische Monatsblätter für Augenheilkunde 203, no. 09 (September 1993): 200–205. http://dx.doi.org/10.1055/s-2008-1045668.

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15

Yawei, Lu, Ma Jiazhi, Shi Longfei, and Quan Yuan. "Multiple interferences suppression with space-polarization null-decoupling for polarimetrie array." Journal of Systems Engineering and Electronics 32, no. 1 (February 2021): 44–52. http://dx.doi.org/10.23919/jsee.2021.000006.

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16

Denk, P. O., M. Markovic, and M. Knorr. "Korrelation zwischen glaukomatösen Halbfeldskotomen und Messungen der Nervenfaserschichtdicke mittels Scanning-Laser-Polarimetrie." Der Ophthalmologe 102, no. 10 (October 2005): 957–67. http://dx.doi.org/10.1007/s00347-005-1211-9.

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17

Figueras i Ventura, Jordi, and Pierre Tabary. "The New French Operational Polarimetric Radar Rainfall Rate Product." Journal of Applied Meteorology and Climatology 52, no. 8 (August 2013): 1817–35. http://dx.doi.org/10.1175/jamc-d-12-0179.1.

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AbstractIn 2012 the Météo France metropolitan operational radar network consists of 24 radars operating at C and S bands. In addition, a network of four X-band gap-filler radars is being deployed in the French Alps. The network combines polarimetric and nonpolarimetric radars. Consequently, the operational radar rainfall algorithm has been adapted to process both polarimetric and nonpolarimetric data. The polarimetric processing chain is available in two versions. In the first version, now operational, polarimetry is only used to correct for attenuation and filter out clear-air echoes. In the second version there is a more extensive use of polarimetry. In particular, the specific differential phase Kdp is used to estimate rainfall rate in intense rain. The performance of the three versions of radar rainfall algorithms (conventional, polarimetric V1, and polarimetric V2) at different frequency bands (S, C, and X) is evaluated by processing radar data of significant events offline and comparing hourly radar rainfall accumulations with hourly rain gauge data. The results clearly show a superior performance of the polarimetric products with respect to the nonpolarimetric ones at all frequency bands, but particularly at higher frequency. The second version of the polarimetric product, which makes a broader use of polarimetry, provides the best overall results.

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Raney, R. Keith. "Hybrid Dual-Polarization Synthetic Aperture Radar." Remote Sensing 11, no. 13 (June 27, 2019): 1521. http://dx.doi.org/10.3390/rs11131521.

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Compact polarimetry for a synthetic aperture radar (SAR) system is reviewed. Compact polarimetry (CP) is intended to provide useful polarimetric image classifications while avoiding the disadvantages of space-based quadrature-polarimetric (quad-pol) SARs. Two CP approaches are briefly described, π/4 and circular. A third form, hybrid compact polarimetry (HCP) has emerged as the preferred embodiment of compact polarimetry. HCP transmits circular polarization and receives on two orthogonal linear polarizations. When seen through its associated data processing and image classification algorithms, HPC’s heritage dates back to the Stokes parameters (1852), which are summarized and explained in plain language. Hybrid dual-polarimetric imaging radars were in the payloads of two lunar-orbiting satellites, India’s Earth-observing RISAT-1, and Japan’s ALOS-2. In lunar or planetary orbit, a satellite equipped with an HCP imaging radar delivers the same class of polarimetric information as Earth-based radar astronomy. In stark contrast to quad-pol, compact polarimetry is compatible with wide swath modes of a SAR, including ScanSAR. All operational modes of the SARs aboard Canada’s three-satellite Radarsat Constellation Mission (RCM) are hybrid dual-polarimetric. Image classification methodologies for HCP data are reviewed, two of which introduce errors for reasons explained. Their use is discouraged. An alternative and recommended group of methodologies yields reliable results, illustrated by polarimetrically classified images. A survey over numerous quantitative studies demonstrates HCP polarimetric classification effectiveness. The results verify that the performance accuracy of the HCP architecture is comparable to the accuracy delivered by a quadrature-polarized SAR. Four appendices are included covering related topics, including comments on inflight calibration of an HCP radar.

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19

Smith, B. A. "Optical Observations of the Beta Pictoris Disk." Highlights of Astronomy 9 (1992): 375. http://dx.doi.org/10.1017/s1539299600009217.

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Multispectral photometric and polarimetrie observations of the Beta Pictoris circumstellar disk, made with a coronagraphic CCD camera at the Las Campanas Observatory between 1984 and 1989 (Smith et al 1992a), indicate that the nearly edge-on, highly flattened disk extends to a distance of more than 60 arcsec (1000au) from the star, with a nearly constant projected thickness of 2.8 arcsec (45 au) on the plane of the sky. A peculiar morphological property of the disk is its apparent asymmetry, with the northeast extension appearing somewhat longer and brighter than its southwest counterpart. Because of its implications for disk dynamics and morphology, this anomalous structure is perhaps the most puzzling phenomenon yet associated with the Beta Pictoris disk and deserves further study.

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Kremmer, Stephan, Andrea Pflug, Arnd Heiligenhaus, Farsad Fanihagh, and Klaus-Peter Steuhl. "Scanning-Laser-Topometrie und Polarimetrie vor und nach Katarakt-Operationen mit Implantation von Intraokularlinsen." Klinische Monatsblätter für Augenheilkunde 214, no. 06 (June 1999): 378–85. http://dx.doi.org/10.1055/s-2008-1034816.

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Wang, Yadong, Tian-You Yu, Alexander V. Ryzhkov, and Matthew R. Kumjian. "Application of Spectral Polarimetry to a Hailstorm at Low Elevation Angle." Journal of Atmospheric and Oceanic Technology 36, no. 4 (April 2019): 567–83. http://dx.doi.org/10.1175/jtech-d-18-0115.1.

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AbstractSpectral polarimetry has the potential to be used to study microphysical properties in relation to the dynamics within a radar resolution volume by combining Doppler and polarimetric measurements. The past studies of spectral polarimetry have focused on using radar measurements from higher elevation angles, where both the size sorting from the hydrometeors’ terminal velocities and polarimetric characteristics are maintained. In this work, spectral polarimetry is applied to data from the 0° elevation angle, where polarimetric properties are maximized. Radar data collected by the C-band University of Oklahoma Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME) during a hailstorm event on 24 April 2011 are used in the analysis. The slope of the spectral differential reflectivity exhibits interesting variations across the hail core, which suggests the presence of size sorting of hydrometeors caused by vertical shear in a turbulent environment. A nearby S-band polarimetric Weather Surveillance Radar-1988 Doppler (KOUN) is also used to provide insights into this hailstorm. Moreover, a flexible numerical simulation is developed for this study, in which different types of hydrometeors such as rain and melting hail can be considered individually or as a combination under different sheared and turbulent conditions. The impacts of particle size distribution, shear, turbulence, attenuation, and mixture of rain and melting hail on polarimetric spectral signatures are investigated with the simulated Doppler spectra and spectral differential reflectivity.

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Yu, Tian-You, Xiao Xiao, and Yadong Wang. "Statistical Quality of Spectral Polarimetric Variables for Weather Radar." Journal of Atmospheric and Oceanic Technology 29, no. 9 (September 1, 2012): 1221–35. http://dx.doi.org/10.1175/jtech-d-11-00090.1.

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Abstract Spectral polarimetry for weather radar capitalizes on both Doppler and polarimetric measurements to reveal polarimetric variables as a function of radial velocity through spectral analysis. For example, spectral differential reflectivity at a velocity represents the differential reflectivity from all the scatterers that have the same radial velocity of interest within the radar resolution volume. Spectral polarimetry has been applied to suppress both ground and biological clutter, retrieve individual drop size distributions from a mixture of different types of hydrometeors, and estimate turbulence intensity, for example. Although spectral polarimetry has gained increasing attention, statistical quality of the estimation of spectral polarimetric variables has not been investigated. In this work, the bias and standard deviation (SD) of spectral differential reflectivity and spectral copolar correlation coefficient estimated from averaged spectra were derived using perturbation method. The results show that the bias and SD of the two estimators depend on the spectral signal-to-noise ratio, spectral copolar correlation coefficient, the number of spectrum average, and spectral differential reflectivity. A simulation to generate time series signals for spectral polarimetry was developed and used to verify the theoretical bias and SD of the two estimators.

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Goïta, Kalifa, Ramata Magagi, Vincent Beauregard, and Hongquan Wang. "Retrieval of Surface Soil Moisture over Wheat Fields during Growing Season Using C-Band Polarimetric SAR Data." Remote Sensing 15, no. 20 (October 12, 2023): 4925. http://dx.doi.org/10.3390/rs15204925.

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Accurate estimation and regular monitoring of soil moisture is very important for many agricultural, hydrological, or climatological applications. Our objective was to evaluate potential contributions of polarimetry to soil moisture estimation during crop growing cycles using RADARSAT-2 C-band images. The research focused on wheat field data collected during Soil Moisture Active Passive Validation Experiment (SMAPVEX12) conducted in 2012 in Manitoba (Canada). A sensitivity analysis was performed to select the most relevant non-polarimetric and polarimetric variables extracted from RADARSAT-2, and statistical models were developed to estimate soil moisture. In fine, three models were developed and validated: a non-polarimetric model based on cross-polarized backscattering coefficient σHV0; a polarimetric mixed model using six polarimetric and non-polarimetric retained variables after the sensitivity analysis; and a simplified polarimetric mixed model considering only the phase difference (ϕHH−VV) and the co-polarized backscattering coefficient σHH0. The validation reveals significant positive contributions of polarimetry. It shows that the non-polarimetric model has a much larger error (RMSE = 0.098 m3/m3) and explains only 19% of observed soil moisture variation compared to the polarimetric mixed model, which has an error of 0.087 m3/m3, with an explained variance of 44%. The simplified model has the lowest error (0.074 m3/m3) and explains 53.5% of soil moisture variation.

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Gledhill, Tim M. "Imaging polarimetry as a diagnostic tool." Proceedings of the International Astronomical Union 4, S259 (November 2008): 613–22. http://dx.doi.org/10.1017/s1743921309031445.

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AbstractSome of the earliest polarimetric measurements made in astronomy were concerned with the polarization of the interstellar medium resulting from dust grains aligned in the Galactic magnetic field. More than 50 years later, polarimetry continues to be an important diagnostic of field structure on size scales ranging from planetary to galactic. The use of both linear and circular polarimetry at optical and infrared wavelengths can provide additional insights into the nature of dust particles, their alignment in magnetic fields and the field topology. Given the science benefits that polarimetry offers it is perhaps surprising that the continued existence of polarimetric facilities on current and next generation large telescopes needs to be ensured.

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25

Li, Xiaobo, Fei Liu, and Jian Liang. "Advanced Polarimetry and Polarimetric Imaging." Photonics 11, no. 4 (March 29, 2024): 317. http://dx.doi.org/10.3390/photonics11040317.

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Boularbah, S., M. Ouarzeddine, and A. Belhadj-Aissa. "Investigation of the capability of the Compact Polarimetry mode to Reconstruct Full Polarimetry mode using RADARSAT2 data." Advanced Electromagnetics 1, no. 1 (June 11, 2012): 19. http://dx.doi.org/10.7716/aem.v1i1.12.

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Recently, there has been growing interest in dual-pol systems that transmit one polarization and receive two polarizations. Souyris et al. proposed a DP mode called compact polarimetry (CP) which is able to reduce the complexity, cost, mass, and data rate of a SAR system while attempting to maintain many capabilities of a fully polarimetric system. This paper provides a comparison of the information content of full quad-pol data and the pseudo quad-pol data derived from compact polarimetric SAR modes. A pseudo-covariance matrix can be reconstructed following Souyris’s approach and is shown to be similar to the full polarimetric (FP) covariance matrix. Both the polarimetric signatures based on the kennaugh matrix and the Freeman and Durden decomposition in the context of this compact polarimetry mode are explored. The Freeman and Durden decomposition is used in our study because of its direct relationship to the reflection symmetry. We illustrate our results by using the polarimetric SAR images of Algiers city in Algeria acquired by the RadarSAT2 in C-band.

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Takahashi, J., Y. Itoh, T. Matsuo, Y. Oasa, Y. P. Bach, and M. Ishiguro. "Polarimetric signature of the oceans as detected by near-infrared Earthshine observations." Astronomy & Astrophysics 653 (September 2021): A99. http://dx.doi.org/10.1051/0004-6361/202039331.

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Context. The discovery of an extrasolar planet with an ocean has crucial importance in the search for life beyond Earth. The polarimetric detection of specularly reflected light from a smooth liquid surface is anticipated theoretically, though the polarimetric signature of Earth’s oceans has not yet been conclusively detected in disk-integrated planetary light. Aims. We aim to detect and measure the polarimetric signature of the Earth’s oceans. Methods. We conducted near-infrared polarimetry for lunar Earthshine and collected data on 32 nights with a variety of ocean fractions in the Earthshine-contributing region. Results. A clear positive correlation was revealed between the polarization degree and ocean fraction. We found hourly variations in polarization in accordance with rotational transition of the ocean fraction. The ratios of the variation to the typical polarization degree were as large as ~0.2–1.4. Conclusions. Our observations provide plausible evidence of the polarimetric signature attributed to Earth’s oceans. Near-infrared polarimetry may be considered a prospective technique in the search for exoplanetary oceans.

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Yin, Junjun, Wooil Moon, and Jian Yang. "Model-Based Pseudo-Quad-Pol Reconstruction from Compact Polarimetry and Its Application to Oil-Spill Observation." Journal of Sensors 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/734848.

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Compact polarimetry is an effective imaging mode for wide area observation, especially for the open ocean. In this study, we propose a new method for pseudo-quad-polarization reconstruction from compact polarimetry based on the three-component decomposition. By using the decomposed powers, the reconstruction model is established as a power-weighted model. Further, the phase of the copolarized correlation is taken into consideration. The phase of double-bounce scattering is closer toπthan to 0, while the phase of surface scattering is closer to 0 than toπ. By considering the negative (double-bounce reflection) and positive (surface reflection) copolarized correlation, the reconstruction model for full polarimetry has a good consistency with the real polarimetric SAR data.L-band ALOS/PALSAR-1 fully polarimetric data acquired on August 27, 2006, over an oil-spill area are used for demonstration. Reconstruction performance is evaluated with a set of typical polarimetric oil-spill indicators. Quantitative comparison is given. Results show that the proposed model-based method is of great potential for oil-spill observation.

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Zhong, Lingzhi, Lipingt Liu, Sheng Feng, Runsheng Ge, and Zhe Zhang. "A 35-GHz polarimetrie Doppler radar and its application for observing clouds associated with Typhoon Nuri." Advances in Atmospheric Sciences 28, no. 4 (June 23, 2011): 945–56. http://dx.doi.org/10.1007/s00376-010-0073-5.

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Guinan, E. F., G. P. McCook, R. H. Koch, and R. J. Pfeiffer. "Evidence for the Roche Lobe Overflow in VV Cephei." Highlights of Astronomy 7 (1986): 211–13. http://dx.doi.org/10.1017/s1539299600006456.

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AbstractThe VV Cep close binary system (O8V + M2 lab; P = 20 3 yrs.) is described from published spectral, radial velocity, photometric, and astrometric results. A long-term photometric monitoring program shows intrinsic variability in a red bandpass. Variability exists on several time scales and the longest of these is attributed to tidal distortion of the cool supergiant by the equally massive hot companion. A theoretical “distortion” light curve, when faced against the observations, indicated the radius of the supergiant to be significantly smaller than the accepted value of ~1600R⊙. This conclusion is examined in the context of a pulse of polarized red light occurring near the time of periastron and interpreted as Roche Lobe overflow of the supergiant envelope. It is shown that the photometric and polarimetrie results may be made accordant, not by appeal to a very large level of scattered red light, but rather by invoking the loss of constraint originally imposed by the Roche Lobe geometry.

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Barnikol, W. K. R., and N. Weiler. "Experimente zur Entwicklung eines implantierbaren und dauernd funktionsfähigen Glukose-Sensors auf Basis der Polarimetrie - Experiments Aimed at Enabling the Development of an Implantable Glucose Sensor Based on Polarimetry." Biomedizinische Technik/Biomedical Engineering 40, no. 5 (1995): 114–20. http://dx.doi.org/10.1515/bmte.1995.40.5.114.

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Williams, Christopher R., and Peter T. May. "Uncertainties in Profiler and Polarimetric DSD Estimates and Their Relation to Rainfall Uncertainties." Journal of Atmospheric and Oceanic Technology 25, no. 10 (October 1, 2008): 1881–87. http://dx.doi.org/10.1175/2008jtecha1038.1.

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Abstract Polarimetric weather radars offer the promise of accurate rainfall measurements by including polarimetric measurements in rainfall estimation algorithms. Questions still remain on how accurately polarimetric measurements represent the parameters of the raindrop size distribution (DSD). In particular, this study propagates polarimetric radar measurement uncertainties through a power-law median raindrop diameter D0 algorithm to quantify the statistical uncertainties of the power-law regression. For this study, the power-law statistical uncertainty of D0 ranged from 0.11 to 0.17 mm. Also, the polarimetric scanning radar D0 estimates were compared with the median raindrop diameters retrieved from two vertically pointing profilers observing the same radar volume as the scanning radar. Based on over 900 observations, the standard deviation of the differences between the two radar estimates was approximately 0.16 mm. Thus, propagating polarimetric measurement uncertainties through D0 power-law regressions is comparable to uncertainties between polarimeteric and profiler D0 estimates.

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Brisco, Brian, Masoud Mahdianpari, and Fariba Mohammadimanesh. "Hybrid Compact Polarimetric SAR for Environmental Monitoring with the RADARSAT Constellation Mission." Remote Sensing 12, no. 20 (October 9, 2020): 3283. http://dx.doi.org/10.3390/rs12203283.

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Canada’s successful space-based earth-observation (EO) radar program has earned widespread and expanding user acceptance following the launch of RADARSAT-1 in 1995. RADARSAT-2, launched in 2007, while providing data continuity for its predecessor’s imaging capabilities, added new polarimetric modes. Canada’s follow-up program, the RADARSAT Constellation Mission (RCM), launched in 2019, while providing continuity for its two predecessors, includes an innovative suite of polarimetric modes. In an effort to make polarimetry accessible to a wide range of operational users, RCM uses a new method called hybrid compact polarization (HCP). There are two essential elements to this approach: (1) transmit only one polarization, circular; and (2) receive two orthogonal polarizations, for which RCM uses H and V. This configuration overcomes the conventional dual and full polarimetric system limitations, which are lacking enough polarimetric information and having a small swath width, respectively. Thus, HCP data can be considered as dual-pol data, while the resulting polarimetric classifications of features in an observed scene are of comparable accuracy as those derived from the traditional fully polarimetric (FP) approach. At the same time, RCM’s HCP methodology is applicable to all imaging modes, including wide swath and ScanSAR, thus overcoming critical limitations of traditional imaging radar polarimetry for operational use. The primary image data products from an HCP radar are different from those of a traditional polarimetric radar. Because the HCP modes transmit circularly polarized signals, the data processing to extract polarimetric information requires different approaches than those used for conventional linearly polarized polarimetric data. Operational users, as well as researchers and students, are most likely to achieve disappointing results if they work with traditional polarimetric processing tools. New tools are required. Existing tutorials, older seminar notes, and reference papers are not sufficient, and if left unrevised, could succeed in discouraging further use of RCM polarimetric data. This paper is designed to provide an initial response to that need. A systematic review of studies that used HCP SAR data for environmental monitoring is also provided. Based on this review, HCP SAR data have been employed in oil spill monitoring, target detection, sea ice monitoring, agriculture, wetland classification, and other land cover applications.

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Tuominen, I., J. Huovelin, Yu S. Efimov, N. M. Shakhovskoy, and A. G. Shcherbakov. "Polarimetry of Stellar Active Regions and Flares." International Astronomical Union Colloquium 104, no. 1 (1989): 419–29. http://dx.doi.org/10.1017/s0252921100032036.

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AbstractObservations of regular and irregular polarimetric variability in late-type stars are reviewed, and the related physical and geometrical effects are discussed. There are indications that the irregular part of the variability could be caused by transient events, possibly associated with flares. Polarimetric observations during flares are reviewed, and preliminary results of new observations of a well-known flare star, YY Geminorum, are presented. The results show that the small flare in YY Gem did not cause any significant variations in linear polarization, while the binary eclipse evidently causes an enhancement in the polarization. The reasons for the difficulties in stellar flare polarimetry are discussed. Finally, future prospects for the observations of flaring stars and for the utilization of linear polarimetry as a complementary method to other techniques of surface imaging of stellar activity and flares are presented.

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Di Marco, Alessandro, Paolo Soffitta, Enrico Costa, Riccardo Ferrazzoli, Fabio La Monaca, John Rankin, Ajay Ratheesh, et al. "Handling the Background in IXPE Polarimetric Data." Astronomical Journal 165, no. 4 (March 3, 2023): 143. http://dx.doi.org/10.3847/1538-3881/acba0f.

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Abstract Imaging X-ray Polarimetry Explorer (IXPE) is a Small Explorer mission by NASA and Agenzia Spaziale Italiana, launched on 2021 December 9, dedicated to investigating X-ray polarimetry allowing angular-, time-, and energy-resolved observations in the 2–8 keV energy band. IXPE is in the science observation phase since 2022 January; it is comprised of three identical telescopes with grazing-incidence mirrors, each one having in the focal plane a gas pixel detector. In this paper, we present a possible guideline to obtain an optimal background selection in polarimetric analysis, and a rejection strategy to remove instrumental background. This work is based on the analysis of IXPE observations, aiming to improve as much as possible the polarimetric sensitivity. In particular, the developed strategies have been applied as a case study to the IXPE observation of the 4U 0142+61 magnetar.

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Rousselet-Perraut, K., C. Stehlé, J. B. Le Bouquin, S. Jankov, and F. Vakili. "Stellar polarimetry with SPIN (Spectro-Polarimetric INterferometry)." EAS Publications Series 9 (2003): 123. http://dx.doi.org/10.1051/eas:2003094.

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González-Gaitán, S., A. M. Mourão, F. Patat, J. P. Anderson, A. Cikota, K. Wiersema, A. B. Higgins, and K. Silva. "Tips and tricks in linear imaging polarimetry of extended sources with FORS2 at the VLT." Astronomy & Astrophysics 634 (February 2020): A70. http://dx.doi.org/10.1051/0004-6361/201936379.

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Context. Polarimetry is a very powerful tool for uncovering various properties of astronomical objects that otherwise remain hidden in standard imaging or spectroscopic observations. While common observations only measure the intensity of light, polarimetric measurements allow us to distinguish and measure the two perpendicular components of the electric field associated with the incoming light. By using polarimetry it is possible to unveil asymmetries in supernova explosions, properties of intervening dust, characteristics of atmosphere of planets, among others. However, the reliable measurement of the low polarization signal from astronomical sources requires a good control of spurious instrumental polarization induced by the various components of the optical system and the detector. Aims. We perform a detailed multi-wavelength calibration study of the FORS2 instrument at the VLT operating in imaging polarimetric mode to characterize the spatial instrumental polarization that may affect the study of extended sources. Methods. We used imaging polarimetry of high signal-to-noise ratio blank field BVRI observations during the full moon, when the polarization is expected to be constant across the field of view and deviations originate from the instrument, and a crowded star cluster in broad-band RI and narrow-band Hα filters, where the individual polarization values of each star across the field can be measured. Results. We find an instrumental polarization pattern that increases radially outwards from the optical axis of the instrument reaching up to 1.4% at the edges, depending on the filter. Our results are closely approximated by an elliptical paraboloid down to less than ∼0.05% accuracy, and ∼0.02% when using non-analytic fits. We present 2D maps to correct for this spurious instrumental polarization. We also give several tips and tricks for analyzing polarimetric measurements of extended sources. Conclusions. FORS2 is a powerful instrument that allows the linear polarimetry of extended sources to be mapped. We present and discuss a methodology that can be used to measure the polarization of such sources, and to correct for the spatial polarization induced in the optical system. This methodology could be applied to polarimetric measurements using other dual-beam polarimeters.

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Gil, José J., and Ignacio San José. "Synthetic Mueller Imaging Polarimetry." Photonics 10, no. 9 (August 24, 2023): 969. http://dx.doi.org/10.3390/photonics10090969.

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The transformation of the state of polarization of a light beam via its linear interaction with a material medium can be modeled through the Stokes–Mueller formalism. The Mueller matrix associated with a given interaction depends on many aspects of the measurement configuration. In particular, different Mueller matrices can be measured for a fixed material sample depending on the spectral profile of the light probe. For a given light probe and a given sample with inhomogeneous spatial behavior, the polarimetric descriptors of the point-to-point Mueller matrices can be mapped, leading to respective polarimetric images. The procedure can be repeated sequentially using light probes with different central frequencies. In addition, the point-to-point Mueller matrices, consecutively measured, can be combined synthetically through convex sums leading to respective new Mueller matrices, in general with increased polarimetric randomness, thus exhibiting specific values for the associated polarimetric descriptors, including the indices of polarimetric purity, and generating new polarimetric images which are different from those obtained from the original Mueller matrices. In this work, the fundamentals for such synthetic generation of additional polarimetric images are described, providing a new tool that enhances the exploitation of Mueller polarimetry.

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AGUDO, IVÁN, SOL N. MOLINA, JOSÉ L. GÓMEZ, ALAN P. MARSCHER, SVETLANA G. JORSTAD, and JOCHEN HEIDT. "MAPCAT: MONITORING AGN WITH POLARIMETRY AT THE CALAR ALTO TELESCOPES." International Journal of Modern Physics: Conference Series 08 (January 2012): 299–302. http://dx.doi.org/10.1142/s2010194512004746.

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We introduce MAPCAT, a long-term observing program for "Monitoring of AGN with Polarimetry at the Calar Alto Telescopes". Multi-spectral-range studies are critical to understand some of the most relevant current problems of high energy astrophysics of blazars such as their high energy emission mechanisms and the location of their γ-ray emission region through event associations across the spectrum. Adding multi-spectral-range polarimetry allows for even more reliable identification of polarized flares across the spectrum in these kind of objects, as well as for more accurate modeling of their magnetic field. As part of a major international effort to study the long term multi-spectral range polarimetric behavior of blazars, MAPCAT uses -since mid 2007- CAFOS on the 2.2m Telescope at the Calar Alto Observatory (Almería, Spain) to obtain monthly optical (R-band) photo-polarimetric measurements of a sample of 34 of the brightest γ-ray, optical, and radio-millimeter blazars accessible from the northern hemisphere.

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Ilyov, S., Ts Genova, P. Troyanova, A. Gisbrecht, and L. Avramov. "Linear polarimetry for analysis of skin degenerative alterations." Journal of Physics: Conference Series 2487, no. 1 (May 1, 2023): 012025. http://dx.doi.org/10.1088/1742-6596/2487/1/012025.

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Abstract Investigation and characterization of the basic polarimetric characteristics on different cutaneous degenerative conditions (Syndrome of Raynaud, lupus, and psoriasis) histological samples was carried out to evaluate the potential for analysis of skin degenerative alterations. Stained and unstained histological samples from the different groups of degenerative conditions of the skin were histologically addressed and were used for polarimetric measurements. Diode laser linearly polarized beam at 635 nm was used for irradiation of the samples and polarimeter, working in the visible spectral range 400-700 nm was applied for polarimetric measurements. We will present the results of histology tissue slides evaluation through Stokes polarimetry in transmission geometry. These studies allow analysis of skin degenerative alterations in collagen anisotropic structuration in extracellular matrix and could be used as indicators of the tissue condition. Therefore, the present work would make possible the establishment of database with polarimetric features of degenerative skin conditions.

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MATT, GIORGIO. "HIGH-ENERGY PHENOMENA STUDIED WITH X–RAY POLARIMETRY." International Journal of Modern Physics D 19, no. 06 (June 2010): 723–28. http://dx.doi.org/10.1142/s0218271810016889.

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After more than 30 years since the last X–ray polarimetric measurements, performed in the 70's by the OSO-8 satellite, thanks to recent technological advances, polarimetry is considered again as a viable technique for studing X–ray sources. In this contribution the author briefly discusses a couple of astrophysical situations, related to the topics of this conference, where X–ray polarimetry can be extremely useful. The author also discusses the observational perspectives, listing the main future space missions (proposed or even already approved) carrying on-board an X–ray polarimeter.

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Islam, Tanvir, and Miguel A. Rico-Ramirez. "An overview of the remote sensing of precipitation with polarimetric radar." Progress in Physical Geography: Earth and Environment 38, no. 1 (December 24, 2013): 55–78. http://dx.doi.org/10.1177/0309133313514993.

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Recent advances in radar remote sensing of precipitation include the development of polarimetric radar, which has the capability of transmitting in both the horizontal ( H) and vertical ( V) polarization states, thus providing additional information on the target precipitation particles. Radar polarimetry has not only been proven to improve data quality and precipitation estimation, but also improves characterization of precipitation particles; thus it has great potential in weather monitoring and forecasting. Realizing the potential of this state-of-the-art technology, meteorological departments across the world are upgrading their radar networks to polarimetric capabilities. Commensurate with this new era in precipitation remote sensing, this article provides an overview of polarimetric radar measurements, emphasizing the intrinsic signatures and their association to precipitation particle shapes, sizes and distributions. The potential research and applications of polarimetric radar signatures in meteorology are discussed. A considerable number of recent peer reviewed journal articles dealing with the topic are included in the bibliography.

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Unal, Christine. "Spectral Polarimetric Radar Clutter Suppression to Enhance Atmospheric Echoes." Journal of Atmospheric and Oceanic Technology 26, no. 9 (September 1, 2009): 1781–97. http://dx.doi.org/10.1175/2009jtecha1170.1.

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Abstract The clutter present in the Doppler spectra of atmospheric targets can be removed by using polarimetry. The purpose is to suppress the Doppler velocity bins where spectral polarimetric parameters have atypical values. This procedure largely improves profiles of moments and polarimetric parameters of atmospheric targets. Several spectral polarimetric clutter-reduction techniques, which are based on thresholding and intended for real-time processing, are discussed in this paper. A new method, the double spectral linear depolarization ratio clutter-suppression technique, is proposed. Very satisfactory performances are obtained with this method, which can be used in the full range of elevations (0°–90°). Spectral polarimetric clutter-suppression techniques for real-time processing were studied for the S-band high-resolution Transportable Atmospheric Radar (TARA) profiler. For this study, precipitation, cloud, and clear-air scattering are considered examples of atmospheric echoes. After successful testing in 2008, the double spectral linear depolarization ratio filter was implemented in the real-time processing of the X-band scanning drizzle radar (IDRA).

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Rubinho, M. S., A. Damineli, A. Carciofi, and D. Moser. "HD151018: strong magnetic field in a giant O-type star?" Proceedings of the International Astronomical Union 12, S329 (November 2016): 442. http://dx.doi.org/10.1017/s1743921317003477.

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AbstractHD151018 is a normal O-type giant with periodic variability of the wind seen in both spectroscopy and linear polarimetry. The characteristics of the wind emission strongly indicate a magnetically confined wind. This work presents the observational results and an initial modelling of the polarimetric modulation of this star.

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Bjorkman, Karen S. "Polarimetry of Binary Stars and Exoplanets." Proceedings of the International Astronomical Union 7, S282 (July 2011): 173–80. http://dx.doi.org/10.1017/s1743921311027281.

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AbstractPolarimetry is a useful diagnostic of asymmetries in both circumstellar environments and binary star systems. Its sensitivity to asymmetries in systems means that it can help to uncover details about system orbital parameters, including providing information about the orbital inclination. Polarimetry can probe the circumstellar and/or circumbinary material as well. A number of significant results on binary systems have been produced by polarimetric studies. One might therefore expect that polarimetry could similarly play a useful role in studies of exoplanets, and a number of possible diagnostics for exoplanets have been proposed. However, the application of polarimetry to exoplanet research is only in preliminary stages, and the difficulties with applying the technique to exoplanets are non-trivial. This review will discuss the successes of polarimetry in analyzing binary systems, and consider the possibilities and challenges for extending similar analysis to exoplanet systems.

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Leiber, Th, and K. Reif. "First Observations by the Bonn Wide-Field Photometer and Polarimeter (WWFPP): Surface Polarimetry of the Crab Nebula." Symposium - International Astronomical Union 161 (1994): 481–83. http://dx.doi.org/10.1017/s0074180900047926.

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To test the performance of the WWFPP in polarimetric mode, we performed surface polarimetry of the Crab nebula in February 1993 using the Asiago 1.82 m telescope of the ‘Osservatorio Astronomico di Padova’. The polarimeter is a new design and enables us to do simultaneous wide-field polarimetry (15 × 15 arcmin field with 0.43 arcsec/pixel) of four polarization angles using a twin Wollaston prism or simultaneous polarimetry of two angles using a double wedge plate with orthogonal sheet polarizers in combination with an achromatic half wave plate. For the observations described here we used the twin Wollaston. The advantages of this design are independency of fluctuations of atmospheric transmission and identical seeing for one set of Stokes parameters. The results of the observations are in agreement with results of other investigators who performed surface polarimetry of the Crab Nebula.

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Chesneau, O., K. Rousselet-Perraut, and F. Vakili. "Interferometry and Stellar Magnetism." International Astronomical Union Colloquium 175 (2000): 174–77. http://dx.doi.org/10.1017/s0252921100055792.

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AbstractThe classical detection of magnetic fields in Be stars remains a challenge due to the sensitivity threshold and geometrical cancelation of the field effects. We propose to study the Zeeman effect using Spectro-Polarimetric INterferometry (SPIN) which consists of the simultaneous use of polarimetry and very high angular resolution provided by long baseline interferometers. As monitoring of the instrumental polarisation is mandatory in order to calibrate interferometric observations in any case, the polarised signal is a natural by-product of interferometers. This method will be tested on the GI2T interferometer thanks to its high spectral resolution and its polarimetric capabilities.

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Tiwari, Vipin, and Nandan S. Bisht. "Combined Jones–Stokes Polarimetry and Its Decomposition into Associated Anisotropic Characteristics of Spatial Light Modulator." Photonics 9, no. 3 (March 17, 2022): 195. http://dx.doi.org/10.3390/photonics9030195.

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Jones–Stokes polarimetry is a robust in vitro polarimetric technique that can be used to investigate the anisotropic properties of a birefringent medium. The study of spatially resolved Jones matrix components of an object is a heuristic approach to extract its phase and polarization information. However, direct interpretation of Jones matrix elements and their decomposition into associated anisotropic properties of a sample is still a challenging research problem that needs to be investigated. In this paper, we experimentally demonstrate combined Jones–Stokes polarimetry to investigate the amplitude, phase, and polarization modulation characteristics of a twisted nematic liquid crystal spatial light modulator (TNLC-SLM). The anisotropic response of the SLM is calibrated for its entire grayscale range. We determine the inevitable anisotropic properties viz., diattenuation, retardance, isotropic absorption, birefringence, and dichroism, which are retrieved from the measured Jones matrices of the SLM using Jones polar decomposition and a novel algebraic approach for Jones matrix decomposition. The results of this study provide a complete polarimetric calibration of the SLM within the framework of its anisotropic characteristics.

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Schinagl, Katharina, Petra Friederichs, Silke Trömel, and Clemens Simmer. "Gamma Drop Size Distribution Assumptions in Bulk Model Parameterizations and Radar Polarimetry and Their Impact on Polarimetric Radar Moments." Journal of Applied Meteorology and Climatology 58, no. 3 (March 2019): 467–78. http://dx.doi.org/10.1175/jamc-d-18-0178.1.

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AbstractA suitable formulation of the rain drop size distribution (DSD) is a prerequisite for a successful assimilation of radar polarimetric information on rain into a numerical weather prediction model. Popular DSD parameterizations in two-moment bulk microphysics schemes use relations between the so-called mean-mass diameter and the DSD shape parameter μ, in order to prevent overly strong size sorting in the models. In radar polarimetry constrained-gamma DSDs with empirical relations between the shape and scale parameter are commonly used. This study compares the different DSD formulations and highlights the differences. Synthetic polarimetric radar observations for X band (9.39 GHz) and S band (3 GHz) were calculated from the different DSDs using the T-matrix method. Depending on the constraint that is assumed for the DSDs, the polarimetric moments exhibit quite different dependencies on the mean diameter, which are particularly striking for differential reflectivity ZDR. To successfully assimilate observed polarimetric moments into atmospheric models, formulations—possibly more flexible than those investigated in this study—have to be found that sufficiently represent microphysical processes and at the same time are consistent with empirical relations derived from disdrometer and radar polarimetric measurements.

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Gil, José J., and Ignacio San José. "Universal Synthesizer of Mueller Matrices Based on the Symmetry Properties of the Enpolarizing Ellipsoid." Symmetry 13, no. 6 (June 1, 2021): 983. http://dx.doi.org/10.3390/sym13060983.

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Polarimetry is today a widely used and powerful tool for nondestructive analysis of the structural and morphological properties of a great variety of material samples, including aerosols and hydrosols, among many others. For each given scattering measurement configuration, absolute Mueller polarimeters provide the most complete polarimetric information, intricately encoded in the 16 parameters of the corresponding Mueller matrix. Thus, the determination of the mathematical structure of the polarimetric information contained in a Mueller matrix constitutes a topic of great interest. In this work, besides a structural decomposition that makes explicit the role played by the diattenuation-polarizance of a general depolarizing medium, a universal synthesizer of Muller matrices is developed. This is based on the concept of an enpolarizing ellipsoid, whose symmetry features are directly linked to the way in which the polarimetric information is organized.

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Journal articles on the topic 'Polarimetrie'

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