Log in

Relevant bibliographies by topics / Optical radar Observations / Journal articles

To see the other types of publications on this topic, follow the link: Optical radar Observations.

Journal articles on the topic 'Optical radar Observations'

Author: Grafiati

Published: 4 June 2021

Last updated: 31 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Optical radar Observations.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Ogawa, T. "Radar observations of ionospheric irregularities at Syowa Station, Antarctica: a brief overview." Annales Geophysicae 14, no. 12 (December 31, 1996): 1454–61. http://dx.doi.org/10.1007/s00585-996-1454-z.

Full text

Abstract:

Abstract. We briefly overview the radar observations that have been made for 30 years at Syowa Station, Antarctica for studying small-scale electron-density irregularities in the southern high-latitude E- and F-region ionosphere. Some observational results (i.e., long-term variations of radio aurora, Doppler spectra with narrow spectral widths and low Doppler velocities, and simultaneous observations of radar and optical auroras) from VHF radars capable of detecting 1.3- to 3-m scale irregularities are presented. A new 50-MHz radar system equipped with phased-antenna arrays began operation in

APA, Harvard, Vancouver, ISO, and other styles

2

Huyan, Zongbo, Yu Jiang, Hengnian Li, Pengbin Ma, and Dapeng Zhang. "Bistatic Radar Observations Correlation of LEO Satellites Considering J2 Perturbation." Mathematics 10, no. 13 (June 23, 2022): 2197. http://dx.doi.org/10.3390/math10132197.

Full text

Abstract:

Space debris near Earth severely interferes with the development of space, and cataloging space objects is increasingly important. Since optical telescopes and radars used to detect space debris only provide short-arc observations, mathematical algorithms are needed to solve problems in the correlation of observations. In this work, an efficient mathematical algorithm based on J2 analytic solutions is put forward. Initial orbit determination (IOD) serves as the starter and orbit determination (OD) with the weighted least-squares method (WLSM) is used to improve the accuracy of the estimated or

APA, Harvard, Vancouver, ISO, and other styles

3

Brosch, N., D. Polishook, R. Helled, S. Schijvarg, and M. Rosenkrantz. "Radar and optical leonids." Atmospheric Chemistry and Physics Discussions 4, no. 2 (March 9, 2004): 1425–47. http://dx.doi.org/10.5194/acpd-4-1425-2004.

Full text

Abstract:

Abstract. We present joint optical-radar observations of meteors collected near the peak of the leonid activity in 2002. We show four examples of joint detections with a large, phased array L-band radar and with intensified video cameras. The general characteristic of the radar-detected optical meteors is that they show the radar detection below the termination of the optical meteor. Therefore, at least some radar events associated with meteor activity are neither head echoes nor trail echoes, but probably indicate the formation of "charged clouds" after the visual meteor is extinguished.

APA, Harvard, Vancouver, ISO, and other styles

4

Brosch, N., D. Polishook, R. Helled, S. Schijvarg, and M. Rosenkrantz. "Radar and optical leonids." Atmospheric Chemistry and Physics 4, no. 4 (July 6, 2004): 1063–69. http://dx.doi.org/10.5194/acp-4-1063-2004.

Full text

Abstract:

Abstract. We present joint optical-radar observations of meteors collected near the peak of the Leonid activity in 2002. We show four examples of joint detections with a large, phased array L-band radar and with intensified video cameras. The general characteristic of the radar-detected optical meteors is that they show the radar detection below the termination of the optical meteor. Therefore, at least some radar events associated with meteor activity are neither head echoes nor trail echoes, but probably indicate the formation of "charged clouds" after the visual meteor is extinguished.

APA, Harvard, Vancouver, ISO, and other styles

5

Mann, Ingrid, Asta Pellinen-Wannberg, and Anders Tjulin. "Meteor studies applying incoherent scatter radar instruments." Proceedings of the International Astronomical Union 10, H16 (August 2012): 181. http://dx.doi.org/10.1017/s1743921314005353.

Full text

Abstract:

AbstractOne of the interesting aspects of optical meteor studies is that the spectral composition of the brightness reveals information about the element composition of the solid particles that enter Earthfs atmosphere from interplanetary space. Deriving composition from optical spectra requires understanding the entry process during which the entering solid interacts with atmospheric species. This is especially so, because most meteors are observed at altitudes where the mean free path changes from tens of meters to millimeters, that is in the 120 km to 80 km altitude range within the atmosph

APA, Harvard, Vancouver, ISO, and other styles

6

Cline, Don, Simon Yueh, Bruce Chapman, Boba Stankov, Al Gasiewski, Dallas Masters, Kelly Elder, et al. "NASA Cold Land Processes Experiment (CLPX 2002/03): Airborne Remote Sensing." Journal of Hydrometeorology 10, no. 1 (February 1, 2009): 338–46. http://dx.doi.org/10.1175/2008jhm883.1.

Full text

Abstract:

Abstract This paper describes the airborne data collected during the 2002 and 2003 Cold Land Processes Experiment (CLPX). These data include gamma radiation observations, multi- and hyperspectral optical imaging, optical altimetry, and passive and active microwave observations of the test areas. The gamma observations were collected with the NOAA/National Weather Service Gamma Radiation Detection System (GAMMA). The CLPX multispectral optical data consist of very high-resolution color-infrared orthoimagery of the intensive study areas (ISAs) by TerrainVision. The airborne hyperspectral optical

APA, Harvard, Vancouver, ISO, and other styles

7

Maki, Masayuki, Masato Iguchi, Takeshi Maesaka, Takahiro Miwa, Toshikazu Tanada, Tomofumi Kozono, Tatsuya Momotani, Akihiko Yamaji, and Ikuya Kakimoto. "Preliminary Results of Weather Radar Observations of Sakurajima Volcanic Smoke." Journal of Disaster Research 11, no. 1 (February 1, 2016): 15–30. http://dx.doi.org/10.20965/jdr.2016.p0015.

Full text

Abstract:

Preliminary results of quantitative analysis of volcanic ash clouds observed over the Sakurajima volcano in Kagoshima, Japan, were obtained by using weather radar and surface instruments. The Ka-band Doppler radar observations showed the inner structure of a volcanic ash column every two minutes after an eruption. Operational X-band polarimetric radar provides information on three-dimensional ash fall amount distribution. The terminal fall velocity of ash particles was studied by using optical disdrometers, together with the main specifications of observation instruments.

APA, Harvard, Vancouver, ISO, and other styles

8

Safargaleev, V., A. Kozlovsky, T. Sergienko, T. K. Yeoman, M. Uspensky, D. M. Wright, H. Nilsson, T. Turunen, and A. Kotikov. "Optical, radar, and magnetic observations of magnetosheath plasma capture during a positive IMF <I>B<sub>z</sub></I> impulse." Annales Geophysicae 26, no. 3 (March 26, 2008): 517–31. http://dx.doi.org/10.5194/angeo-26-517-2008.

Full text

Abstract:

Abstract. We present a multi-instrument study of the ionospheric response to a northward turning of the IMF. The observations were made in the near-noon (11:00 MLT) sector on Svalbard (at 75° MLAT). The data set includes auroral observations, ionospheric flows obtained from the EISCAT and CUTLASS radars, the spectral width of the HF radar backscatter, particle precipitation and plasma flow data from the DMSP F13 satellite, and Pc1 frequency band pulsations observed by induction magnetometers. Careful collocation of all the observations has been made with the HF radar backscatter located by a r

APA, Harvard, Vancouver, ISO, and other styles

9

Sekar, R., D. Chakrabarty, R. Narayanan, S. Sripathi, A. K. Patra, and K. S. V. Subbarao. "Characterization of VHF radar observations associated with equatorial Spread F by narrow-band optical measurements." Annales Geophysicae 22, no. 9 (September 23, 2004): 3129–36. http://dx.doi.org/10.5194/angeo-22-3129-2004.

Full text

Abstract:

Abstract. The VHF radars have been extensively used to investigate the structures and dynamics of equatorial Spread F (ESF) irregularities. However, unambiguous identification of the nature of the structures in terms of plasma depletion or enhancement requires another technique, as the return echo measured by VHF radar is proportional to the square of the electron density fluctuations. In order to address this issue, co-ordinated radar backscatter and thermospheric airglow intensity measurements were carried out during March 2003 from the MST radar site at Gadanki. Temporal variations of 630.0

APA, Harvard, Vancouver, ISO, and other styles

10

Ostro, S. J. "Radar and Optical Observations of Asteroid 1998 KY26." Science 285, no. 5427 (July 23, 1999): 557–59. http://dx.doi.org/10.1126/science.285.5427.557.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Nam, Christine C. W., and Johannes Quaas. "Evaluation of Clouds and Precipitation in the ECHAM5 General Circulation Model Using CALIPSO and CloudSat Satellite Data." Journal of Climate 25, no. 14 (July 15, 2012): 4975–92. http://dx.doi.org/10.1175/jcli-d-11-00347.1.

Full text

Abstract:

Abstract Observations from Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and CloudSat satellites are used to evaluate clouds and precipitation in the ECHAM5 general circulation model. Active lidar and radar instruments on board CALIPSO and CloudSat allow the vertical distribution of clouds and their optical properties to be studied on a global scale. To evaluate the clouds modeled by ECHAM5 with CALIPSO and CloudSat, the lidar and radar satellite simulators of the Cloud Feedback Model Intercomparison Project’s Observation Simulator Package are used. Comparison of

APA, Harvard, Vancouver, ISO, and other styles

12

Takewaka, Satoshi. "Visibility of River Plume Fronts with an X-Band Radar." Journal of Sensors 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/6594847.

Full text

Abstract:

A land-based X-band radar was employed to observe river plume fronts at the mouth of the Tenryu River, Japan. Time-averaged radar images captured fronts extending offshore from the river’s mouth as bright streaks. Comparisons between satellite optical images and radar images confirm that streaky features in the radar image represent color river plume fronts. Further corroboration comes from field observations of water temperature, salinity, and turbidity conducted simultaneously with the radar measurements. When a survey ship crossed the front, the measured properties varied discontinuously, s

APA, Harvard, Vancouver, ISO, and other styles

13

Kastinen, Daniel, Torbjørn Tveito, Juha Vierinen, and Mikael Granvik. "Radar observability of near-Earth objects using EISCAT 3D." Annales Geophysicae 38, no. 4 (July 15, 2020): 861–79. http://dx.doi.org/10.5194/angeo-38-861-2020.

Full text

Abstract:

Abstract. Radar observations can be used to obtain accurate orbital elements for near-Earth objects (NEOs) as a result of the very accurate range and range rate measureables. These observations allow the prediction of NEO orbits further into the future and also provide more information about the properties of the NEO population. This study evaluates the observability of NEOs with the EISCAT 3D 233 MHz 5 MW high-power, large-aperture radar, which is currently under construction. Three different populations are considered, namely NEOs passing by the Earth with a size distribution extrapolated fr

APA, Harvard, Vancouver, ISO, and other styles

14

Shchukin, G. G., and V. V. Bulkin. "Meteorological passive-active radar observations." Journal of Communications Technology and Electronics 56, no. 5 (May 2011): 509–30. http://dx.doi.org/10.1134/s1064226911030089.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Shuygina, N. V., and E. I. Yagudina. "The FK5 equinox and equator from combined radar and optical data of the near-earth asteroids." Symposium - International Astronomical Union 172 (1996): 469–74. http://dx.doi.org/10.1017/s0074180900127895.

Full text

Abstract:

Minor planets optical observations have long been used for the purpose of establishing a Celestial reference frame. Being in existence since the early 1960s modern high-accuracy radar measurements of the so-called near-Earth asteroids (NEAs) have been widely extended to the orbit determination process and predicting of the next apparition of the asteroid. Even few radar measurements, when added to optical ones, significantly improve asteroid's ephemeris and reduce standard deviations of the orbital elements (Yeomans et al., 1987). The idea to connect optical and radar data in the problem of th

APA, Harvard, Vancouver, ISO, and other styles

16

Milan, S. E., M. Lester, S. W. H. Cowley, J. Moen, P. E. Sandholt, and C. J. Owen. "Meridian-scanning photometer, coherent HF radar, and magnetometer observations of the cusp: a case study." Annales Geophysicae 17, no. 2 (February 28, 1999): 159–72. http://dx.doi.org/10.1007/s00585-999-0159-5.

Full text

Abstract:

Abstract. The dynamics of the cusp region and post-noon sector for an interval of predominantly IMF By, Bz < 0 nT are studied with the CUTLASS Finland coherent HF radar, a meridian-scanning photometer located at Ny Ålesund, Svalbard, and a meridional network of magnetometers. The scanning mode of the radar is such that one beam is sampled every 14 s, and a 30° azimuthal sweep is completed every 2 minutes, all at 15 km range resolution. Both the radar backscatter and red line (630 nm) optical observations are closely co-located, especially at their equatorward boundary. The optical and radar

APA, Harvard, Vancouver, ISO, and other styles

17

Ohsawa, Ryou, Akira Hirota, Kohei Morita, Shinsuke Abe, Daniel Kastinen, Johan Kero, Csilla Szasz, et al. "Relationship between radar cross section and optical magnitude based on radar and optical simultaneous observations of faint meteors." Planetary and Space Science 194 (December 2020): 105011. http://dx.doi.org/10.1016/j.pss.2020.105011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Rodger, A. S., S. B. Mende, T. J. Rosenberg, and K. B. Baker. "Simultaneous optical and HF radar observations of the ionospheric cusp." Geophysical Research Letters 22, no. 15 (August 1, 1995): 2045–48. http://dx.doi.org/10.1029/95gl01797.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Frey, H. U., G. Haerendel, D. Knudsen, S. Buchert, and O. H. Bauer. "Optical and radar observations of the motion of auroral arcs." Journal of Atmospheric and Terrestrial Physics 58, no. 1-4 (January 1996): 57–69. http://dx.doi.org/10.1016/0021-9169(95)00019-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Zambrano-Marin, Luisa Fernanda, Ellen S. Howell, Patrick A. Taylor, Sean E. Marshall, Maxime Devogèle, Anne K. Virkki, Dylan C. Hickson, Edgard G. Rivera-Valentín, Flaviane C. F. Venditti, and Jon D. Giorgini. "Radar and Optical Characterization of Near-Earth Asteroid 2019 OK." Planetary Science Journal 3, no. 6 (June 1, 2022): 138. http://dx.doi.org/10.3847/psj/ac63cd.

Full text

Abstract:

Abstract We conducted radar observations of near-Earth asteroid 2019 OK on 2019 July 25 using the Arecibo Observatory S-band (2380 MHz, 12.6 cm) planetary radar system. Based on Arecibo and optical observations the apparent diameter is between 70 and 130 m. Combined with an absolute magnitude of H = 23.3 ± 0.3, the optical albedo of 2019 OK is likely between 0.05 and 0.17. Our measured radar circular polarization ratio of μ C = 0.33 ± 0.03 indicates 2019 OK is likely not a V- or E-type asteroid and is most likely a C- or S-type. The measured radar echo bandwidth of 39 ± 2 Hz restricts the appa

APA, Harvard, Vancouver, ISO, and other styles

21

Belavin, N. A., A. B. Silantyev, Yu V. Babkin, V. I. Kim, and A. V. Timoshenko. "RESOURCE EFFICIENT CONTROL OF LONG-RANGE DETECTION RADAR FOR MONITORING OF HIGH EARTH ORBIT OBJECTS WITH SIMULTANEOUS CONTROL OF BARRIER ZONE." T-Comm 16, no. 9 (2022): 4–12. http://dx.doi.org/10.36724/2072-8735-2022-16-9-4-12.

Full text

Abstract:

Radar surveillance (RS) of space objects has a number of advantages over the optical one. An urgent task is the RS of remote spacecraft, including high Earth orbit (HEO) spacecraft with the apogee height of more than 2500 km above the Earth's surface. In modern radars, well-known models, methods and technical solutions for observing remote spacecraft are implemented by increasing the duration (energy) of transmitted signals and observation time. This restriction does not allow to simultaneously detect and track objects of the "barrier zone" (BZ) while solving routine tasks using a long-range d

APA, Harvard, Vancouver, ISO, and other styles

22

Milan, S. E., M. Lester, N. Sato, H. Takizawa, and J. P. Villain. "Investigation of the relationship between optical auroral forms and HF radar E region backscatter." Annales Geophysicae 18, no. 6 (June 30, 2000): 608–17. http://dx.doi.org/10.1007/s00585-000-0608-7.

Full text

Abstract:

Abstract. The SuperDARN HF radars have been employed in the past to investigate the spectral characteristics of coherent backscatter from L-shell aligned features in the auroral E region. The present study employs all-sky camera observations of the aurora from Husafell, Iceland, and the two SuperDARN radars located on Iceland, Þykkvibær and Stokkseyri, to determine the optical signature of such backscatter features. It is shown that, especially during quiet geomagnetic conditions, the backscatter region is closely associated with east-west aligned diffuse auroral features, and that the two mov

APA, Harvard, Vancouver, ISO, and other styles

23

Koustov, A., K. Hosokawa, N. Nishitani, T. Ogawa, and K. Shiokawa. "Rankin Inlet PolarDARN radar observations of duskward moving Sun-aligned optical forms." Annales Geophysicae 26, no. 9 (September 12, 2008): 2711–23. http://dx.doi.org/10.5194/angeo-26-2711-2008.

Full text

Abstract:

Abstract. On 15 February 2007, several duskward moving sun-aligned (SA) auroral forms have been observed by the all-sky camera at Resolute Bay, Nunavut (Canada). Concurrent observations with the Rankin Inlet (RANK) PolarDARN HF radar within the field-of-view of the camera showed signatures of moving auroral forms in all signal parameters with the most remarkable effects being the echo power drop and velocity reversal as the arc reached a specific radar beam/gate. Spatial and temporal variations of the velocity in the vicinity of the SA form are investigated. It is shown that the form-associate

APA, Harvard, Vancouver, ISO, and other styles

24

Tsuda, T., T. Nakamura, A. Nomura, T. D. Kawahara, C. Nagasawa, M. Abo, S. Okano, M. Taguchi, and M. Ejiri. "Coordinated observations of the mesopause region with radar and optical techniques." Advances in Space Research 26, no. 6 (January 2000): 907–16. http://dx.doi.org/10.1016/s0273-1177(00)00029-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Michell, R. G., D. Janches, M. Samara, J. L. Hormaechea, C. Brunini, and I. Bibbo. "Simultaneous optical and radar observations of meteor head-echoes utilizing SAAMER." Planetary and Space Science 118 (December 2015): 95–101. http://dx.doi.org/10.1016/j.pss.2015.04.018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Narziev, Mirhusen. "Physical properties of the meteoroids using simultaneous radar and optical observations." Planetary and Space Science 173 (September 2019): 42–48. http://dx.doi.org/10.1016/j.pss.2018.11.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Samara, M., and R. G. Michell. "Optical and radar observations of small-scale polar cap auroral structures." Journal of Atmospheric and Solar-Terrestrial Physics 105-106 (December 2013): 308–12. http://dx.doi.org/10.1016/j.jastp.2012.11.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Larsen, M. F., D. L. Hysell, Q. H. Zhou, S. M. Smith, J. Friedman, and R. L. Bishop. "Imaging coherent scatter radar, incoherent scatter radar, and optical observations of quasiperiodic structures associated with sporadicElayers." Journal of Geophysical Research: Space Physics 112, A6 (June 2007): n/a. http://dx.doi.org/10.1029/2006ja012051.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Клунко, Евгений, Evgeny Klunko, Максим Еселевич, Maxim Eselevich, Владимир Тергоев, and Vladimir Tergoev. "Progress cargo spacecraft observed with the AZT-33IK optical telescope." Solar-Terrestrial Physics 2, no. 3 (October 27, 2016): 22–31. http://dx.doi.org/10.12737/22282.

Full text

Abstract:

In this paper, we describe a telescope and measuring equipment used for optical observations of Progress cargo spacecraft (PCS), which were made during Radar–Progress space experiment sessions. We also demonstrate object tracking and measurement techniques. The observations were made with the optical telescope AZT-33IK at the Sayan Solar Observatory of ISTP SB RAS. During many of the sessions, we registered optical phenomena that occurred in regions of space surrounding the PCS and appeared due to the work of PCS onboard engines. The data we obtained can be used to independently control the ge

APA, Harvard, Vancouver, ISO, and other styles

30

Michell, R. G., K. A. Lynch, C. J. Heinselman, and H. C. Stenbaek-Nielsen. "High time resolution PFISR and optical observations of naturally enhanced ion acoustic lines." Annales Geophysicae 27, no. 4 (April 1, 2009): 1457–67. http://dx.doi.org/10.5194/angeo-27-1457-2009.

Full text

Abstract:

Abstract. Observations of naturally enhanced ion acoustic lines (NEIALs) taken with the Poker Flat Incoherent Scatter Radar (PFISR) using a mode with very high time resolution are presented. The auroral event took place over Poker Flat, Alaska on 8 February 2007 at 09:35 UT (~22:00 MLT), and the radar data are complemented by common-volume high-resolution auroral imaging. The NEIALs occurred during only one of the standard 15-s integration periods. The raw data of this time show very intermittent NEIALs which occur only during a few very short time intervals (≤1 s) within the 15-s period. The

APA, Harvard, Vancouver, ISO, and other styles

31

Dorozhkin, N. S., V. Yu Zhukov, and V. M. Mel'nikov. "Doppler observations with stock meteorological radar." Radiophysics and Quantum Electronics 37, no. 11 (November 1994): 910–13. http://dx.doi.org/10.1007/bf01057280.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Jin, Huiran, and Giorgos Mountrakis. "Fusion of optical, radar and waveform LiDAR observations for land cover classification." ISPRS Journal of Photogrammetry and Remote Sensing 187 (May 2022): 171–90. http://dx.doi.org/10.1016/j.isprsjprs.2022.03.010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

LIU, Jianjun, Hongqiao HU, Desheng HAN, Yonghua LIU, Qinghe ZHANG, and S. Yukimatu Akira. "Optical and SuperDARN radar observations of duskside shock aurora over Zhongshan Station." ADVANCES IN POLAR SCIENCE 24, no. 1 (January 7, 2014): 60–68. http://dx.doi.org/10.3724/sp.j.1085.2013.00060.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Gustavsson, B., M. J. Kosch, A. Senior, A. J. Kavanagh, B. U. E. Brändström, and E. M. Blixt. "Combined EISCAT radar and optical multispectral and tomographic observations of black aurora." Journal of Geophysical Research: Space Physics 113, A6 (June 2008): n/a. http://dx.doi.org/10.1029/2007ja012999.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Yeoman, T. K., M. Lester, S. W. H. Cowley, S. E. Milan, J. Moen, and P. E. Sandholt. "Simultaneous observations of the cusp in optical, DMSP and HF radar data." Geophysical Research Letters 24, no. 17 (September 1, 1997): 2251–54. http://dx.doi.org/10.1029/97gl02072.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Frey, H. U., S. Frey, B. S. Lanchester, and M. Kosch. "Optical tomography of the aurora and EISCAT." Annales Geophysicae 16, no. 10 (October 31, 1998): 1332–42. http://dx.doi.org/10.1007/s00585-998-1332-y.

Full text

Abstract:

Abstract. Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used durin

APA, Harvard, Vancouver, ISO, and other styles

37

Peña-Luque, Santiago, Sylvain Ferrant, Mauricio C. R. Cordeiro, Thomas Ledauphin, Jerome Maxant, and Jean-Michel Martinez. "Sentinel-1&2 Multitemporal Water Surface Detection Accuracies, Evaluated at Regional and Reservoirs Level." Remote Sensing 13, no. 16 (August 19, 2021): 3279. http://dx.doi.org/10.3390/rs13163279.

Full text

Abstract:

Water stock monitoring is a major issue for society on a local and global scale. Sentinel-1&2 satellites provide frequent acquisitions to track water surface dynamics, proxy variables to enable water surface volume monitoring. How do we combine such observations along time for each sensor? What advantages and disadvantages of single-date, monthly or time-windowed estimations? In this context, we analysed the impact of merging information through different types and lengths of time-windows. Satellite observations were processed separately on optical (Sentinel-2) and radar (Sentinel-1) water

APA, Harvard, Vancouver, ISO, and other styles

38

Milan, S. E., M. Lester, N. Sato, and H. Takizawa. "On the altitude dependence of the spectral characteristics of decametre-wavelength E region backscatter and the relationship with optical auroral forms." Annales Geophysicae 19, no. 2 (February 28, 2001): 205–17. http://dx.doi.org/10.5194/angeo-19-205-2001.

Full text

Abstract:

Abstract. Observations of E region backscatter by the Ice-land East SuperDARN HF radar from the 30 minute period 2330 to 2400 UT on 13 September 1999 are presented, along with simultaneous observations of auroral luminosity from two all-sky cameras. Interferometric techniques are employed to estimate the altitude of origin of each echo observed by the radar. Under investigation is a region of backscatter which is L-shell aligned and exists in a region of low auroral luminosity bounded to the north and the south by two auroral arcs. The spectral characteristics of the backscatter fall into thre

APA, Harvard, Vancouver, ISO, and other styles

39

Kavanagh, A. J., J. A. Wild, and F. Honary. "Observations of omega bands using an imaging riometer." Annales Geophysicae 27, no. 11 (November 6, 2009): 4183–95. http://dx.doi.org/10.5194/angeo-27-4183-2009.

Full text

Abstract:

Abstract. We present a case study of an omega band current system from 11 May 1998 using data from the Imaging Riometer for Ionospheric Studies (IRIS) in Finland. For the first time, images of a substorm-related omega band in cosmic noise absorption are shown. The substorm in question was one of a string that occurred on that day; inspection of geostationary satellite data indicates that this was a sawtooth event. Using a previously established statistical relationship, the IRIS data is used to provide maps of Hall conductance and compared with previous estimates utilising both HF and VHF cohe

APA, Harvard, Vancouver, ISO, and other styles

40

Rożek, A., S. C. Lowry, M. C. Nolan, P. A. Taylor, L. A. M. Benner, A. Fitzsimmons, T. J. Zegmott, et al. "Shape model and spin-state analysis of PHA contact binary (85990) 1999 JV6 from combined radar and optical observations." Astronomy & Astrophysics 631 (November 2019): A149. http://dx.doi.org/10.1051/0004-6361/201936302.

Full text

Abstract:

Context. The potentially hazardous asteroid (85990) 1999 JV6 has been a target of previously published thermal-infrared observations and optical photometry. It has been identified as a promising candidate for possible Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect detection. Aims. The YORP effect is a small thermal-radiation torque considered to be a key factor in spin-state evolution of small Solar System bodies. In order to detect YORP on 1999 JV6 we developed a detailed shape model and analysed the spin-state using both optical and radar observations. Methods. For 1999 JV6, we collecte

APA, Harvard, Vancouver, ISO, and other styles

41

Chapuis, Anne, Cecilie Rolstad, and Richard Norland. "Interpretation of amplitude data from a ground-based radar in combination with terrestrial photogrammetry and visual observations for calving monitoring of Kronebreen, Svalbard." Annals of Glaciology 51, no. 55 (2010): 34–40. http://dx.doi.org/10.3189/172756410791392781.

Full text

Abstract:

AbstractA ground-based radar has been used successfully for monitoring calving events and velocities at Kronebreen, Svalbard, for two test seasons in 2007 and 2008. We use daily terrestrial optical photogrammetry and continuous visual observation to validate the interpretation of a 116 hour ground-based radar amplitude of return signal data recorded from 26 to 30 August 2008. The radar was placed –4 km from the glacier. It measured at high temporal rate (2 Hz) and the antenna lobe covered a width of –700 m of the front. The calving-front geometry was extracted from the optical images, and its

APA, Harvard, Vancouver, ISO, and other styles

42

Vandemark, D., B. Chapron, J. Sun, G. H. Crescenti, and H. C. Graber. "Ocean Wave Slope Observations Using Radar Backscatter and Laser Altimeters." Journal of Physical Oceanography 34, no. 12 (December 1, 2004): 2825–42. http://dx.doi.org/10.1175/jpo2663.1.

Full text

Abstract:

Abstract Combination of laser and radar aboard an aircraft is used to directly measure long gravity wave surface tilting simultaneously with nadir-viewing microwave backscatter from the sea surface. The presented dataset is extensive, encompassing varied wind conditions over coastal and open-ocean wave regimes. Laser-derived slope statistics and Ka-band (36 GHz) radar backscatter are detailed separately to document their respective variations versus near-surface wind speed. The slope statistics, measured for λ &gt; 1–2 m, show good agreement with Cox and Munk's oil-slickened sea measuremen

APA, Harvard, Vancouver, ISO, and other styles

43

Ostro, Steven J. "Radar Contributions to Asteroid Astrometry and Dynamics." International Astronomical Union Colloquium 165 (1997): 87–96. http://dx.doi.org/10.1017/s0252921100046406.

Full text

Abstract:

Almost every radar observation of asteroids has measured some characteristics of the distribution of echo power in time delay (range) and Doppler frequency (radial velocity). Such measurements, which are orthogonal to optical plane-of-sky angular astrometry, are also done in the well-known, “absolute” reference frame of the planetary ephemerides, often with fractional precision that is much finer than can be achieved with other kinds of groundbased observations; they therefore can dramatically refine orbits and ephemerides. This statement is most true for near-Earth asteroids (NEAs), which con

APA, Harvard, Vancouver, ISO, and other styles

44

Khan, H., M. Lester, J. A. Davies, S. E. Milan, and P. E. Sandholt. "Multi-instrument study of the dynamic cusp during dominant IMF <i>B<sub>y</sub></i> conditions." Annales Geophysicae 21, no. 3 (March 31, 2003): 693–708. http://dx.doi.org/10.5194/angeo-21-693-2003.

Full text

Abstract:

Abstract. We present multi-instrument observations using the meridian scanning photometer (MSP) at NyAlesund, the EISCAT Svalbard radar (ESR) and the CUTLASS Finland HF radar, to investigate the dynamics of the cusp region during pulsed reconnection events. The optical data obtained from the MSP indicate the presence of several poleward-moving auroral forms (PMAFs) which have been previously identified as the auroral signature of pulsed reconnection. Furthermore, the optical green line (557.7 nm) luminosity indicates a loss of emission equatorward of the location of the onset of the PMAFs, cha

APA, Harvard, Vancouver, ISO, and other styles

45

Gorbatsky, V., N. Shpilev, and Ye Lebedeva. "Sea currents monitoring in the coastal areas by the remote observation methods." Transactions of the Krylov State Research Centre 1, no. 399 (March 15, 2022): 159–67. http://dx.doi.org/10.24937/2542-2324-2022-1-399-159-167.

Full text

Abstract:

Object and purpose of research. The compare analysis carried out on the vorticies structure optical satellite pictures observation of the sea surface and the velocities field obtained by the ground HF Doppler radar. The purpose of this research is estimation of the possibility on fast monitoring feasibility assessment for the changes in littoral waters dynamics through joint application of satellite surveillance, radar probing of sea currents, wind data and numerical simulation of water circulation in the area under investigation. Materials and methods. The Sea surface observation data obtaine

APA, Harvard, Vancouver, ISO, and other styles

46

Schroeder, Dustin M., Julian A. Dowdeswell, Martin J. Siegert, Robert G. Bingham, Winnie Chu, Emma J. MacKie, Matthew R. Siegfried, Katherine I. Vega, John R. Emmons, and Keith Winstein. "Multidecadal observations of the Antarctic ice sheet from restored analog radar records." Proceedings of the National Academy of Sciences 116, no. 38 (September 3, 2019): 18867–73. http://dx.doi.org/10.1073/pnas.1821646116.

Full text

Abstract:

Airborne radar sounding can measure conditions within and beneath polar ice sheets. In Antarctica, most digital radar-sounding data have been collected in the last 2 decades, limiting our ability to understand processes that govern longer-term ice-sheet behavior. Here, we demonstrate how analog radar data collected over 40 y ago in Antarctica can be combined with modern records to quantify multidecadal changes. Specifically, we digitize over 400,000 line kilometers of exploratory Antarctic radar data originally recorded on 35-mm optical film between 1971 and 1979. We leverage the increased geo

APA, Harvard, Vancouver, ISO, and other styles

47

Zegmott, Tarik J., S. C. Lowry, A. Rożek, B. Rozitis, M. C. Nolan, E. S. Howell, S. F. Green, C. Snodgrass, A. Fitzsimmons, and P. R. Weissman. "Detection of the YORP effect on the contact binary (68346) 2001 KZ66 from combined radar and optical observations." Monthly Notices of the Royal Astronomical Society 507, no. 4 (September 3, 2021): 4914–32. http://dx.doi.org/10.1093/mnras/stab2476.

Full text

Abstract:

Abstract The Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect is a small thermal-radiation torque experienced by small asteroids, and is considered to be crucial in their physical and dynamical evolution. It is important to understand this effect by providing measurements of YORP for a range of asteroid types to facilitate the development of a theoretical framework. We are conducting a long-term observational study on a selection of near-Earth asteroids to support this. We focus here on (68346) 2001 KZ66, for which we obtained both optical and radar observations spanning a decade. This allo

APA, Harvard, Vancouver, ISO, and other styles

48

Pellinen-Wannberg, A., A. Westman, G. Wannberg, and K. Kaila. "Meteor fluxes and visual magnitudes from EISCAT radar event rates: a comparison with cross-section based magnitude estimates and optical data." Annales Geophysicae 16, no. 11 (November 30, 1998): 1475–85. http://dx.doi.org/10.1007/s00585-998-1475-x.

Full text

Abstract:

Abstract. Incoherent scatter radars (ISR) are versatile instruments for continuous monitoring of ionisation processes in the Earth's atmosphere. EISCAT, The European Incoherent Scatter facility has proven effective also in meteor studies. The time resolution of the radar can be reduced to a few milliseconds, sufficient to resolve the passage of individual meteors through the narrow ISR beam. Methods for group and phase velocity determination of the meteoroids and the discrepancy between the results related to the target behaviour are presented. The radar cross sections of echoes associated wit

APA, Harvard, Vancouver, ISO, and other styles

49

Vinogradova, T. A., O. M. Kochetova, Yu A. Chernetenko, V. A. Shor, and E. I. Yagudina. "The orbit of asteroid (99942) Apophis as determined from optical and radar observations." Solar System Research 42, no. 4 (July 30, 2008): 271–80. http://dx.doi.org/10.1134/s0038094608040011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Michell, R. G., M. DeLuca, D. Janches, R. Chen, and M. Samara. "Simultaneous optical and dual-frequency radar observations of small mass meteors at Arecibo." Planetary and Space Science 166 (February 2019): 1–8. http://dx.doi.org/10.1016/j.pss.2018.07.015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!