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Journal articles on the topic 'Spectral Doppler measurements'

Author: Grafiati

Published: 10 March 2023

Last updated: 31 July 2025

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1

Moisseev, Dmitri N., and V. Chandrasekar. "Nonparametric Estimation of Raindrop Size Distributions from Dual-Polarization Radar Spectral Observations." Journal of Atmospheric and Oceanic Technology 24, no. 6 (2007): 1008–18. http://dx.doi.org/10.1175/jtech2024.1.

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This paper presents a method to retrieve raindrop size distributions (DSD) from slant profile dual-polarization Doppler spectra observations. It is shown that using radar measurements taken at a high elevation angle raindrop size distributions can be retrieved without making an assumption on the form of a DSD. In this paper it is shown that drop size distributions can be retrieved from Doppler power spectra by compensating for the effect of spectrum broadening and mean velocity shift. To accomplish that, spectrum deconvolution is used where the spectral broadening kernel width and wind velocit

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2

Панчук, В. Е., В. Л. Афанасьев, А. Г. Пельменев, М. В. Юшкин, Г. С. Жуклевич, and С. В. Ларионов. "Doppler measurements of stars: evolution of accuracy and some perspectives." Научные труды Института астрономии РАН, no. 4 (December 31, 2021): 129–35. http://dx.doi.org/10.51194/inasan.2021.6.4.006.

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Перечислены основные этапы повышения точности доплеровских измерений спектров звезд и связанные с этимтехнологические прорывы. Упоминаются методы интерференционной спектроскопии, ориентированные как на сни-жение стоимости массовых доплеровских измерений, так и на увеличение спектрального разрешения до значений,превосходящих спектральное разрешение согласованного спектрографа высокого разрешения. The main stages of increasing the accuracy of Doppler measurements of stellar spectra and related technological break-throughs are listed. Methods of interference spectroscopy are mentioned, which are

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Carlos, A. Gómez-Vega, A. Gutiérrez Carlos, J. Jaime-Rodríguez José, et al. "Doppler spectrum measurements of vehicular radio channels using a narrowband sounder." Revista Facultad de Ingeniería, Universidad de Antioquia, no. 93 (April 26, 2019): 32–40. https://doi.org/10.17533/10.17533/udea.redin.20190405.

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This paper describes the implementation of a narrowband sounder for Doppler power spectrum (DPS) measurements of vehicular communication channels. The narrowband channel sounder is implemented using general purpose equipment, making such measurement platform easy to replicate for didactic and research purposes. To demonstrate the practical value of this framework, a measurement campaign was conducted to obtain empirical information about the spectral characteristics of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) multipath radio channels in the 700 MHz band. The collected data

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Gómez Vega, Carlos A., Carlos A. Gutiérrez, Jose J. Jaime Rodriguez, et al. "Doppler spectrum measurements of vehicular radio channels using a narrowband sounder." Revista Facultad de Ingeniería Universidad de Antioquia, no. 93 (August 23, 2019): 32–40. http://dx.doi.org/10.17533/10.17533/udea.redin.20190405.

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This paper describes the implementation of a narrowband sounder for Doppler power spectrum (DPS) measurements of vehicular communication channels. The narrowband channel sounder is implemented using general purpose equipment, making such measurement platform easy to replicate for didactic and research purposes. To demonstrate the practical value of this framework, a measurement campaign was conducted to obtain empirical information about the spectral characteristics of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) multipath radio channels in the 700 MHz band. The collected data

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Cifuentes-Lorenzen, Alejandro, James B. Edson, Christopher J. Zappa, and Ludovic Bariteau. "A Multisensor Comparison of Ocean Wave Frequency Spectra from a Research Vessel during the Southern Ocean Gas Exchange Experiment." Journal of Atmospheric and Oceanic Technology 30, no. 12 (2013): 2907–25. http://dx.doi.org/10.1175/jtech-d-12-00181.1.

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Abstract Obtaining accurate measurements of wave statistics from research vessels remains a challenge due to the platform motion. One principal correction is the removal of ship heave and Doppler effects from point measurements. Here, open-ocean wave measurements were collected using a laser altimeter, a Doppler radar microwave sensor, a radar-based system, and inertial measurement units. Multiple instruments were deployed to capture the low- and high-frequency sea surface displacements. Doppler and motion correction algorithms were applied to obtain a full 1D (0.035–1.3 ± 0.2 Hz) wave spectru

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Chaxel, Y., E. M. Griffin, and N. P. Meredith. "Spectral analysis techniques for doppler lidar measurements." Advances in Space Research 21, no. 10 (1998): 1441–44. http://dx.doi.org/10.1016/s0273-1177(97)00657-1.

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7

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 (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

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8

Mattesini, Paolo, Alessandro Ramalli, Lorena Petrusca, Olivier Basset, Herve Liebgott, and Piero Tortoli. "Spectral Doppler Measurements With 2-D Sparse Arrays." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 67, no. 2 (2020): 278–85. http://dx.doi.org/10.1109/tuffc.2019.2944090.

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9

Anandan, V. K., C. J. Pan, T. Rajalakshmi, and G. Ramachandra Reddy. "Multitaper spectral analysis of atmospheric radar signals." Annales Geophysicae 22, no. 11 (2004): 3995–4003. http://dx.doi.org/10.5194/angeo-22-3995-2004.

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Abstract. Multitaper spectral analysis using sinusoidal taper has been carried out on the backscattered signals received from the troposphere and lower stratosphere by the Gadanki Mesosphere-Stratosphere-Troposphere (MST) radar under various conditions of the signal-to-noise ratio. Comparison of study is made with sinusoidal taper of the order of three and single tapers of Hanning and rectangular tapers, to understand the relative merits of processing under the scheme. Power spectra plots show that echoes are better identified in the case of multitaper estimation, especially in the region of a

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Liu, Liping, and Jiafeng Zheng. "Algorithms for Doppler Spectral Density Data Quality Control and Merging for the Ka-Band Solid-State Transmitter Cloud Radar." Remote Sensing 11, no. 2 (2019): 209. http://dx.doi.org/10.3390/rs11020209.

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The Chinese Ka-band solid-state transmitter cloud radar (CR) can operate in three different work modes with different pulse widths and coherent integration and non-coherent integration numbers to meet the requirement for long-term cloud measurements. The CR was used to observe cloud and precipitation data in southern China in 2016. In order to resolve the data quality problems caused by coherent integration and pulse compression, which are used to detect weak cloud in the cloud radar, this study focuses on analyzing the consistencies of reflectivity spectra using the three modes and the influe

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Lanchester, B. S., M. Galand, S. C. Robertson, et al. "High resolution measurements and modeling of auroral hydrogen emission line profiles." Annales Geophysicae 21, no. 7 (2003): 1629–43. http://dx.doi.org/10.5194/angeo-21-1629-2003.

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Abstract. Measurements in the visible wavelength range at high spectral resolution (1.3 Å) have been made at Longyearbyen, Svalbard (15.8 E,78.2 N) during an interval of intense proton precipitation. The shape and Doppler shift of hydrogen Balmer beta line profiles have been compared with model line profiles, using as input ion energy spectra from almost coincident passes of the FAST and DMSP spacecraft. The comparison shows that the simulation contains the important physical processes that produce the profiles, and confirms that measured changes in the shape and peak wave-length of the hydrog

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12

Dérian, Pierre, Christopher F. Mauzey, and Shane D. Mayor. "Wavelet-Based Optical Flow for Two-Component Wind Field Estimation from Single Aerosol Lidar Data." Journal of Atmospheric and Oceanic Technology 32, no. 10 (2015): 1759–78. http://dx.doi.org/10.1175/jtech-d-15-0010.1.

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AbstractA motion estimation algorithm was applied to image sequences produced by a horizontally scanning elastic backscatter lidar. The algorithm, a wavelet-based optical flow estimator named Typhoon, produces dense two-component vector flow fields that correspond to the apparent motion of microscale aerosol features. To validate the efficacy of this approach for the remote measurement of wind fields in the lower atmosphere, an experiment was conducted in Chico, California, in 2013 and 2014. The flow fields, estimated every 17 s, were compared with measurements from an independent Doppler lida

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13

Fang, Ming, Bruce Albrecht, Eunsil Jung, Pavlos Kollias, Haflidi Jonsson, and Ivan PopStefanija. "Retrieval of Vertical Air Motion in Precipitating Clouds Using Mie Scattering and Comparison with In Situ Measurements." Journal of Applied Meteorology and Climatology 56, no. 3 (2017): 537–53. http://dx.doi.org/10.1175/jamc-d-16-0158.1.

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AbstractFor the first time, the Mie notch retrieval technique is applied to airborne cloud Doppler radar observations in warm precipitating clouds to retrieve the vertical air velocity profile above the aircraft. The retrieval algorithm prescribed here accounts for two major sources of bias: aircraft motion and horizontal wind. The retrieval methodology is evaluated using the aircraft in situ vertical air velocity measurements. The standard deviations of the residuals for the retrieved and in situ measured data for an 18-s time segment are 0.21 and 0.24 m s−1, respectively; the mean difference

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14

Yeo, Sunmi, Changhan Yoon, Ching-Ling Lien, Tai-Kyong Song, and K. Kirk Shung. "Monitoring of Adult Zebrafish Heart Regeneration Using High-Frequency Ultrasound Spectral Doppler and Nakagami Imaging." Sensors 19, no. 19 (2019): 4094. http://dx.doi.org/10.3390/s19194094.

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This paper reports the feasibility of Nakagami imaging in monitoring the regeneration process of zebrafish hearts in a noninvasive manner. In addition, spectral Doppler waveforms that are typically used to access the diastolic function were measured to validate the performance of Nakagami imaging. A 30-MHz high-frequency ultrasound array transducer was used to acquire backscattered echo signal for spectral Doppler and Nakagami imaging. The performances of both methods were validated with flow and tissue-mimicking phantom experiments. For in vivo experiments, both spectral Doppler and Nakagami

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Bascom, Peter A. J., K. Wayne Johnston, Richard S. C. Cobbold, and Matadial Ojha. "Defining the limitations of measurements from Doppler spectral recordings." Journal of Vascular Surgery 24, no. 1 (1996): 34–45. http://dx.doi.org/10.1016/s0741-5214(96)70142-8.

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Lee, Bor-Ray, Huihua Kenny Chiang, Yi-Hong Chou, Cheng-Deng Kuo, Jia-Horng Wang, and San-Kan Lee. "Implementation of spectral width Doppler in pulsatile flow measurements." Ultrasound in Medicine & Biology 25, no. 8 (1999): 1221–27. http://dx.doi.org/10.1016/s0301-5629(99)00083-6.

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Prunier, Fabrice, Roger Gaertner, Liliane Louedec, Jean-Baptiste Michel, Jean-Jacques Mercadier, and Brigitte Escoubet. "Doppler echocardiographic estimation of left ventricular end-diastolic pressure after MI in rats." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 1 (2002): H346—H352. http://dx.doi.org/10.1152/ajpheart.01050.2001.

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The spectral Doppler mitral flow pattern, alone or combined with tissue Doppler mitral annulus velocity, can be used to predict left ventricular (LV) filling pressure in humans, whereas invasive hemodynamic measurements are still required in the rat. This study was undertaken to assess whether LV end-diastolic pressure (LVEDP) can be estimated using Doppler echocardiography in the rat after myocardial infarction (MI). Thirty-seven rats (23 rats with MI after left coronary artery ligation and 14 sham-operated rats) were evaluated 3 mo after surgery with echo-Doppler and invasive hemodynamic mea

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Ueda, Hiromasa, Tetsuo Fukui, Mizuo Kajino, Mitsuaki Horiguchi, Hiroyuki Hashiguchi, and Shoichiro Fukao. "Eddy Diffusivities for Momentum and Heat in the Upper Troposphere and Lower Stratosphere Measured by MU Radar and RASS, and a Comparison of Turbulence Model Predictions." Journal of the Atmospheric Sciences 69, no. 1 (2012): 323–37. http://dx.doi.org/10.1175/jas-d-11-023.1.

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Abstract Recently, middle- and upper-atmosphere Doppler radar (MU radar) has enabled the measurement of middle-atmosphere turbulence from radar backscatter Doppler spectra. In this work, eddy diffusivities for momentum Km in the upper troposphere and lower stratosphere during clear-air conditions were derived from direct measurements of the Reynolds stress and vertical gradient of mean wind velocity measured by MU radar. Eddy diffusivity for heat Kh below 8 km was determined from measurements of temperature fluctuations by the Radio Acoustic Sounding System (RASS) attached to the MU radar. The

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19

Kobayashi, Takahisa, and Ahoro Adachi. "Retrieval of Arbitrarily Shaped Raindrop Size Distributions from Wind Profiler Measurements." Journal of Atmospheric and Oceanic Technology 22, no. 4 (2005): 433–42. http://dx.doi.org/10.1175/jtech1705.1.

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Abstract An efficient iterative retrieval method for arbitrarily shaped raindrop size distributions (ITRAN) is developed for Doppler spectra measured with a wind profiler. A measured Doppler spectrum is a convolution of the precipitation spectrum and the turbulent spectrum. Deconvolution of the Doppler spectra is achieved through repeated convolutions. The developed method assumes no prior shape of drop size distributions and automatically obtains raindrop size distributions; additionally, it can be applied to large data volumes. Furthermore, it is insensitive to initial values. The method was

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Engler, N., R. Latteck, B. Strelnikov, W. Singer, and M. Rapp. "Turbulent energy dissipation rates observed by Doppler MST Radar and by rocket-borne instruments during the MIDAS/MaCWAVE campaign 2002." Annales Geophysicae 23, no. 4 (2005): 1147–56. http://dx.doi.org/10.5194/angeo-23-1147-2005.

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Abstract. During the MIDAS/MaCWAVE campaign in summer 2002 we have observed turbulence using Doppler beam steering measurements obtained from the ALWIN VHF radar at Andøya/Northern Norway. This radar was operated in the Doppler beam steering mode for turbulence investigations during the campaign, as well as in spaced antenna mode, for continuously measuring the background wind field. The real-time data analysis of the Doppler radar backscattering provided the launch conditions for the sounding rockets. The spectral width data observed during the occurrence of PMSE were corrected for beam and s

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Jacovich, Taylor, Daniel Patnaude, Patrick Slane, et al. "Doppler Broadening and Line-of-sight Effects in Core-collapse Supernovae and Young Remnants." Astrophysical Journal 951, no. 1 (2023): 57. http://dx.doi.org/10.3847/1538-4357/acd0ad.

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Abstract The dynamics and spectral characteristics of supernova ejecta reveal details of the supernova energetics, explosive nucleosynthesis, and evolution of the progenitor. However, in practice, this important diagnostic information is only derived from CCD-resolution X-ray spectra of shock-heated material. If the spectra were to be observed at higher resolution, then important clues to the explosion energetics would be obvious through measurements of bulk Doppler motions and turbulence in the ejecta. Likewise, the unshocked ejecta in supernovae and young remnants are responsible for obscuri

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Mashnich, G. "Spectral Observations of Filament Activation." Proceedings of the International Astronomical Union 8, S300 (2013): 447–48. http://dx.doi.org/10.1017/s1743921313011496.

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AbstractStudies of solar filament (prominence) activation and eruption are often based on measurements of intensity fluctuations in various solar emission bands and rarely on Doppler velocity measurements. The goal of this paper is to analyze the process of quiescent filament activation, using spectral data, and its associated events in solar UV band. Motions have been examined in a small southern fragment of a quiescent, extended filament in the northern hemisphere prior to and during its activation on June 14 2012. A part of the fragment disappeared after the filament activation.

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Prikner, K. "Simultaneous conjugate ground-satellite ULF pulsation measurements at the middle latitudes." Annales Geophysicae 15, no. 6 (1997): 645–55. http://dx.doi.org/10.1007/s00585-997-0645-6.

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Abstract. The spectra of three series of simultaneous ground (Budkov Observatory) and satellite (Freja) ULF measurements have been processed. The following features were studied in the FFT spectra, power-spectra and cross-spectra of the six-minute samples, recorded during quasi-conjugate approaches of Freja to the local Budkov magnetic field line: (a) the Doppler frequency shift (about 1mHz and less) in the predominant and some particular spectral components on Freja; (b) the amplitude relations between the ground and satellite (ratios 0.3 to 0.8); (c) phase shifts between particular signal co

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Thurnherr, A. M. "The Finescale Response of Lowered ADCP Velocity Measurements Processed with Different Methods." Journal of Atmospheric and Oceanic Technology 29, no. 4 (2012): 597–600. http://dx.doi.org/10.1175/jtech-d-11-00158.1.

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Abstract In a paper published in 2002 in this journal, K. Polzin et al. derive corrections for spectra of vertical shear calculated from lowered acoustic Doppler current profiler (LADCP) velocity data. To illustrate and validate the corrections, they use velocities derived with a specific implementation of the shear method for LADCP processing that is no longer supported or widely used. In several recent publications, spectral corrections specific to this old processing method have been applied without modification to LADCP data processed with the more modern and much more widely used velocity

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Monselesan, D. P., R. J. Morris, P. L. Dyson, and M. R. Hyde. "Southern high-latitude Digisonde observations of ionosphere E-region Bragg scatter during intense lacuna conditions." Annales Geophysicae 22, no. 8 (2004): 2819–35. http://dx.doi.org/10.5194/angeo-22-2819-2004.

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Abstract. During summer months at solar cycle minimum, F-region lacuna and slant-Es conditions (SEC) are common features of daytime ionograms recorded around local magnetic noon at Casey, Antarctica. Digisonde measurements of drift velocity height profiles show that the occurrence of lacuna prevents the determination of F-region drift velocities and also affects E-region drift velocity measurements. Unique E-region spectral features revealed as intervals of Bragg scatter superimposed on typical background E-region reflection were observed in Digisonde Doppler spectra during intense lacuna cond

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Cloutier, Guy, Louis Allard, and Louis-Gilles Durand. "Characterization of Blood Flow Turbulence With Pulsed-Wave and Power Doppler Ultrasound Imaging." Journal of Biomechanical Engineering 118, no. 3 (1996): 318–25. http://dx.doi.org/10.1115/1.2796013.

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Blood flow turbulence downstream of a concentric 86 percent area reduction stenosis was characterized using absolute and relative Doppler spectral broadening measurements, relative Doppler velocity fluctuation, and Doppler backscattered power. Bidi-mensional mappings of each Doppler index were obtained using a 10 MHz pulsed-wave Doppler system. Calf red cells suspended in a saline solution were used to scatter ultrasound and were circulated in an in vitro steady flow loop model. Results showed that the absolute spectral broadening was not a good index of turbulence because it was strongly affe

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Zhou, Xiao-Hui, Dong-Ping Wang, and Dake Chen. "Global Wavenumber Spectrum with Corrections for Altimeter High-Frequency Noise." Journal of Physical Oceanography 45, no. 2 (2015): 495–503. http://dx.doi.org/10.1175/jpo-d-14-0144.1.

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AbstractThe altimetry wavenumber spectra of sea surface height (SSH) provide a unique dataset for testing of geostrophic turbulence. While SSH spectral slopes of k−11/3 and k−5 are expected from theories and numerical simulations, the altimetry spectra from the original unfiltered and instrument noise–corrected data often are too shallow, falling between k−2 and k−3. In this study, the possibility that the flattened spectral slopes are partly due to contamination by unresolved high-frequency (<10 days) motions is tested. A spatiotemporal filter based on empirical orthogonal function expansi

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Unal, Christine. "High-Resolution Raindrop Size Distribution Retrieval Based on the Doppler Spectrum in the Case of Slant Profiling Radar." Journal of Atmospheric and Oceanic Technology 32, no. 6 (2015): 1191–208. http://dx.doi.org/10.1175/jtech-d-13-00225.1.

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AbstractDoppler spectra from vertically profiling radars are usually considered to retrieve the raindrop size distribution (DSD). However, to exploit both fall velocity spectrum and polarimetric measurements, Doppler spectra acquired in slant profiling mode should be explored. Rain DSD samples are obtained from simultaneously measured vertical and slant profile Doppler spectra and evaluated. In particular, the effect of the horizontal wind and the averaging time are investigated.The Doppler spectrum provides a way to retrieve the DSD, the radial wind, and a spectral broadening factor by means

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Hofmann, J., F. L. Deubner, B. Fleck, and W. Schmidt. "Polarimetric Measurements of the Fine Structure of a Sunspot Penumbra." International Astronomical Union Colloquium 141 (1993): 44–47. http://dx.doi.org/10.1017/s0252921100028748.

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AbstractObservations of a fairly regular sunspot penumbra near disk center have been carried out using a Stokes V polarimeter at the German Vacuum-Tower-Telescope in Izaña, Tenerife. We obtained two-dimensional spectral data by scanning the limb oriented sector of the penumbra in steps of 1” with the slit parallel to the solar limb. From Stokes V and Stokes I spectra of four magnetic sensitive lines (Fe I 5247.1, Cr I 5247.6, Fe I 5250.2, and Fe I 5250.7) obtained with 1024 × 1024 pixel CCDs we have determined Doppler shifts and several magnetic parameters. The results of a correlation analysi

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Ferrone, Alfonso, Anne-Claire Billault-Roux, and Alexis Berne. "ERUO: a spectral processing routine for the Micro Rain Radar PRO (MRR-PRO)." Atmospheric Measurement Techniques 15, no. 11 (2022): 3569–92. http://dx.doi.org/10.5194/amt-15-3569-2022.

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Abstract. The Micro Rain Radar PRO (MRR-PRO) is a K-band Doppler weather radar, using frequency-modulated continuous-wave (FMCW) signals, developed by Metek Meteorologische Messtechnik GmbH (Metek) as a successor to the MRR-2. Benefiting from four datasets collected during two field campaigns in Antarctica and Switzerland, we developed a processing library for snowfall measurements named ERUO (Enhancement and Reconstruction of the spectrUm for the MRR-PRO), with a twofold objective. Firstly, the proposed method addresses a series of issues plaguing the radar variables, including interference l

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Hoitink, A. J. F., H. C. Peters, and M. Schroevers. "Field Verification of ADCP Surface Gravity Wave Elevation Spectra." Journal of Atmospheric and Oceanic Technology 24, no. 5 (2007): 912–22. http://dx.doi.org/10.1175/jtech2000.1.

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Abstract Acoustic Doppler current profilers (ADCPs) can measure orbital velocities induced by surface gravity waves, yet the ADCP estimates of these velocities are subject to a relatively high noise level. The present paper introduces a linear filtration technique to significantly reduce the influence of noise and turbulence from energy spectra of combined orbital velocity measurements. Data were collected in 13-m-deep water with a 1.2-MHz ADCP sampling in mode 12, where a collocated wave buoy was used for verification. The surface elevation spectra derived from the filtrated and nonfiltrated

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Löhner-Böttcher, J., W. Schmidt, R. Schlichenmaier, H. P. Doerr, T. Steinmetz, and R. Holzwarth. "Absolute velocity measurements in sunspot umbrae." Astronomy & Astrophysics 617 (September 2018): A19. http://dx.doi.org/10.1051/0004-6361/201832886.

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Context. In sunspot umbrae, convection is largely suppressed by the strong magnetic field. Previous measurements reported on negligible convective flows in umbral cores. Based on this, numerous studies have taken the umbra as zero reference to calculate Doppler velocities of the ambient active region.Aims. We aim to clarify the amount of convective motion in the darkest part of umbrae, by directly measuring Doppler velocities with an unprecedented accuracy and precision.Methods. We performed spectroscopic observations of sunspot umbrae with the Laser Absolute Reference Spectrograph (LARS) at t

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Palmer, A. J. "A spectral model for turbulence and microphysics dynamics in an ice cloud." Nonlinear Processes in Geophysics 3, no. 1 (1996): 23–28. http://dx.doi.org/10.5194/npg-3-23-1996.

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Abstract. A one-dimensional, nine-mode spectral model for temperature, velocity, and the mixing ratios of suspended and precipitating ice-particle components is shown to be consistent with ice-cloud observations. The observations include Doppler radar time-series measurements of a single winter ice cloud and direct measurements of mean particle size vs. icewater content for a set of ice clouds. Fitting of the model to the Doppler vertical-velocity measurements allows a prediction to be made of the vertical scale and turbulent Prandtl number active in the ice-cloud vertical motions. The model i

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Dufournet, Y., and H. W. J. Russchenberg. "Towards the improvement of cloud microphysical retrievals using simultaneous Doppler and polarimetric radar measurements." Atmospheric Measurement Techniques 4, no. 10 (2011): 2163–78. http://dx.doi.org/10.5194/amt-4-2163-2011.

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Abstract. Radar-based retrievals are often employed to characterize the microphysical properties of cloud hydrometeors, i.e. their phases, habits, densities as well as their respective size and orientation distributions. These techniques are based on a synergetic use of different cloud observation sensor(s) and microphysical model(s) where the information extracted from both sensors and models is combined and converted into microphysical cloud properties. However, the amount of available information is often limited, which forces current microphysical retrieval techniques to base their algorit

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Reiners, Ansgar. "Magnetic field observations of low-mass stars." Proceedings of the International Astronomical Union 4, S259 (2008): 339–44. http://dx.doi.org/10.1017/s1743921309030701.

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AbstractDirect measurements of magnetic fields in low-mass stars of spectral class M have become available during the last years. This contribution summarizes the data available on direct magnetic measurements in M dwarfs from Zeeman analysis in integrated and polarized light. Strong magnetic fields at kilo-Gauss strength are found throughout the whole M spectral range, and so far all field M dwarfs of spectral type M6 and later show strong magnetic fields. Zeeman Doppler images from polarized light find weaker fields, which may carry important information on magnetic field generation in parti

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Halpern, Mark. "Measurement of the Dipole Moment of the Cosmic Background Radiation at mm and Sub-mm Wavelengths." Symposium - International Astronomical Union 124 (1987): 63–68. http://dx.doi.org/10.1017/s0074180900159030.

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Sensitive measurements of a dipole anisotropy of the Cosmic Background Radiation at wavelengths of 1.7 and 0.8 mm are presented. Under the assumption that the dipole moment is caused by a doppler shift, these measurements are of sufficient precision to constrain spectral distortions of the CBR at short wavelengths. Measurements of the brightness and shape of diffuse galactic emission are also presented.

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Stȩślicki, Marek, Janusz Sylwester, Stefan Płocieniak, et al. "Soft X-ray polarimeter-spectrometer SOLPEX." Proceedings of the International Astronomical Union 11, S320 (2015): 450–55. http://dx.doi.org/10.1017/s1743921316002106.

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AbstractWe present an innovative soft X-ray polarimeter and spectrometer SOLPEX. The instrument is to be mounted aboard the ISS within the Russian science complex KORTES. The measurements to be made by SOLPEX are expected to be of unprecedented quality in terms of sensitivity to detect the soft-X-ray polarization of solar emission emanating from active regions and flares in particular. Simultaneous measurements of the polarization degree and the other characteristics (eg. evolution of the spectra) constitute the last, rather unexplored area of solar X-ray spectroscopy providing substantial dia

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Wijn, P. F. F., P. van der Sar, T. H. J. M. Gootzen, M. H. J. Tilmans, and S. H. Skotnicki. "Value of the spectral broadening index in continuous wave Doppler measurements." Medical and Biological Engineering and Computing 25, no. 4 (1987): 377–85. http://dx.doi.org/10.1007/bf02443357.

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David, J. Y., S. A. Jones, and D. P. Giddens. "Modern spectral analysis techniques for blood flow velocity and spectral measurements with pulsed Doppler ultrasound." IEEE Transactions on Biomedical Engineering 38, no. 6 (1991): 589–96. http://dx.doi.org/10.1109/10.81584.

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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 (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 estima

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Sadrieh, Seyed Nima, Ali Broumandan, and Gérard Lachapelle. "Doppler Characterization of a Mobile GNSS Receiver in Multipath Fading Channels." Journal of Navigation 65, no. 3 (2012): 477–94. http://dx.doi.org/10.1017/s037346331200015x.

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Global Navigation Satellite Systems (GNSS) Doppler measurements are commonly used for velocity-based relative positioning and aiding Inertial Navigation Systems (INS) in signal degraded environments. The aim of this paper is to characterise the Doppler measurements in GNSS harsh multipath environments. In multipath fading situations such as indoor and urban canyon environments, multipath components arrive to the receiver antenna from different paths and directions. These give rise to various Doppler shifts that cause errors in the velocity solution. In this work the Doppler measurements discre

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Wilhelm, K., W. Curdt, A. H. Gabriel, et al. "‘Sumer’ – Solar Ultraviolet Measurements of Emitted Radiation." International Astronomical Union Colloquium 144 (1994): 619–24. http://dx.doi.org/10.1017/s0252921100026178.

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AbstractThe experiment Solar Ultraviolet Measurements of Emitted Radiation (SUMER) is designed for the investigations of plasma flow characteristics, turbulence and wave motions, plasma densities and temperatures, structures and events associated with solar magnetic activity in the chromosphere, the transition zone and the corona. Specifically, SUMER will measure profiles and intensities of extreme ultraviolet (EUV) lines emitted in the solar atmosphere ranging from the upper chromosphere to the lower corona; determine line broadenings, spectral positions and Doppler shifts with high accuracy;

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Razenkov, Ilya I., and Edwin W. Eloranta. "Advances in atmospheric temperature profile measurements using high spectral resolution lidar." EPJ Web of Conferences 176 (2018): 01023. http://dx.doi.org/10.1051/epjconf/201817601023.

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This paper reports the atmospheric temperature profile measurements using a University of Wisconsin-Madison High Spectral Resolution Lidar (HSRL) and describes improvements in the instrument performance. HSRL discriminates between Mie and Rayleigh backscattering [1]. Thermal motion of molecules broadens the spectrum of the transmitted laser light due to Doppler effect. The HSRL exploits this property to allow the absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different line widths are used to resolve temperat

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Yang, Mingchao, Yiwei Wang, Zhibo Fang, et al. "A Novel Doppler Estimation Approach Using ORBCOMM Signals for High-Precision Positioning." Electronics 13, no. 24 (2024): 4882. https://doi.org/10.3390/electronics13244882.

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Positioning based on Low Earth Orbit (LEO) satellite Signals of Opportunity (SOP) often relies on Doppler observations. Therefore, the accuracy of Doppler frequency measurements significantly impacts the positioning performance. Traditional frequency estimation methods for ORBCOMM satellite signals are typically implemented in the frequency domain and neglect the impact of the “frequency chirp” effect on measurement accuracy, which leads to low computational efficiency, poor noise resistance, and limited estimation accuracy. To address this issue, a high-precision frequency estimation method c

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Kalesse, H., W. Szyrmer, S. Kneifel, P. Kollias, and E. Luke. "Fingerprints of a riming event on cloud radar Doppler spectra: observations and modeling." Atmospheric Chemistry and Physics Discussions 15, no. 20 (2015): 28619–58. http://dx.doi.org/10.5194/acpd-15-28619-2015.

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Abstract. Radar Doppler spectra measurements are exploited to study a riming event when precipitating ice from a seeder cloud sediments through a supercooled liquid water (SLW) layer. The observations were collected during the deployment of the Atmospheric Radiation Measurement Program's (ARM) mobile facility AMF2 at Hyytiälä, Finland during the BAECC (Biogenic Aerosols – Effects on Clouds and Climate Snowfall Experiment) field campaign. The presented analysis of the height evolution of the radar Doppler spectra is a state-of-the-art retrieval with profiling cloud radars in SLW layers beyond t

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Mauder, Matthias, Michael Eggert, Christian Gutsmuths, et al. "Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar." Atmospheric Measurement Techniques 13, no. 2 (2020): 969–83. http://dx.doi.org/10.5194/amt-13-969-2020.

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Abstract. Accurate measurements of turbulence statistics in the atmosphere are important for eddy-covariance measurements, wind energy research, and the validation of atmospheric numerical models. Sonic anemometers are widely used for these applications. However, these instruments are prone to probe-induced flow distortion effects, and the magnitude of the resulting errors has been debated due to the lack of an absolute reference instrument under field conditions. Here, we present the results of an intercomparison experiment between a CSAT3B sonic anemometer and a high-resolution bistatic Dopp

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Dufournet, Y., and H. W. J. Russchenberg. "Towards the improvement of cloud microphysical retrievals using simultaneous Doppler and polarimetric radar measurements." Atmospheric Measurement Techniques Discussions 4, no. 1 (2011): 527–62. http://dx.doi.org/10.5194/amtd-4-527-2011.

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Abstract. Radar-based retrievals are often employed to characterize the microphysical properties of cloud hydrometeors, i.e., their phases, habits, densities as well as their respective size and orientation distributions. These techniques are based on a synergetic use of different cloud observation sensor(s) and microphysical algorithm(s) where the information extracted from both sensors and models are combined and converted into microphysical cloud properties. However, the amount of available information is often limited, which forces current microphysical retrieval techniques to base their a

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Çeliktas, M., H. Birbiçer, K. Aikimbaev, H. Özbek, E. Akgül, and F. Binokay. "Utility of color duplex sonography in the assessment of efficacy of the stellate ganglion blockade." Acta Radiologica 44, no. 5 (2003): 494–97. http://dx.doi.org/10.1080/j.1600-0455.2003.00106.x.

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Purpose: To assess the hemodynamic changes in the upper extremity arteries after sympathetic ganglion blockade (SGB) by using spectral Doppler parameters and to determine the applicability of these parameters for the evaluation of SGB efficacy. Material and Methods: Spectral Doppler parameters (peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (mean V), flow volume, resistive and pulsatility indices (RI, PI), inner arterial diameters (intima to intima) (D) with simultaneous recordings of heart rate (HR), systolic and diastolic blood pressures and upper extremity surface

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Huang, Jiayun, Liwei Yang, Jiqin Zhang, and Hao Hu. "Granular Fertilizer Mass Flow Measurement and Vehicle Experiments Based on Microwave Doppler Method." Applied Engineering in Agriculture 37, no. 1 (2021): 135–47. http://dx.doi.org/10.13031/aea.14013.

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HighlightsA microwave Doppler-based fertilizer mass flow measurement system was developed.The measurement system was applied in vehicle experiments.Power spectra of mass flow signal and vibration signal were obtained and analyzed.Interference suppression algorithm based on CA-CFAR reduced vibration interference.Fertilizer mass flow measurement accuracy was improved by interference suppression.Abstract. The fertilizer mass flow measurement system is typically installed on the fertilizer applicator. However, vehicle vibrations are inevitable during field operation of fertilizing equipment, and c

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McKenna, Mervyn Alexander, Michelle Clare Bonfield, and Teresa Robinson. "Levels of agreement in the measurements of carotid artery ultrasound across a regional vascular network." Ultrasound 26, no. 2 (2018): 101–9. http://dx.doi.org/10.1177/1742271x17751255.

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Introduction Duplex ultrasound is often the sole imaging modality used in diagnosing carotid artery disease. However, the reproducibility and repeatability of scientists in determining the peak systolic velocity and end diastolic velocity of the internal carotid artery and common carotid artery (CCA) is widely debated. Study aim To investigate intra- and inter-operator variability in diagnostic ultrasound of the carotid arteries across a centralised vascular network using a healthy test subject. To identify potential causes of variability and highlight areas for improvement. Methods Fifteen va

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