Zeitschriftenartikel: „Radar meteorology“

1

Browning, K. A. „Uses of radar in meteorology“. Contemporary Physics 27, Nr. 6 (November 1986): 499–517. http://dx.doi.org/10.1080/00107518608211028.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Hallett, John, Melanie Wetzel und Steven Rutledge. „Field Training in Radar Meteorology“. Bulletin of the American Meteorological Society 74, Nr. 1 (Januar 1993): 17–22. http://dx.doi.org/10.1175/1520-0477(1993)074<0017:ftirm>2.0.co;2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Lombardo, F., F. Napolitano, F. Russo, G. Scialanga, L. Baldini und E. Gorgucci. „Rainfall estimation and ground clutter rejection with dual polarization weather radar“. Advances in Geosciences 7 (16.02.2006): 127–30. http://dx.doi.org/10.5194/adgeo-7-127-2006.

Der volle Inhalt der Quelle

Annotation:

Abstract. Conventional radars, used for atmospheric remote sensing, usually operate at a single polarization and frequency to estimate storm parameters such as rainfallrate and water content. Because of the high variability of the drop size distribution conventional radars do not succeed in obtaining detailed information because they just use horizontal reflectivity. The potentiality of the dual-polarized weather radar is investigated, in order to reject the ground-clutter, using differential reflectivity. In this light, a radar meteorology campaign was conducted over the city of Rome (Italy), collecting measurements by the polarimetric Doppler radar Polar 55C and by a raingauge network. The goodness of the results is tested by comparison of radar rainfall estimates with raingauges rainfall measurements.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Zrnić, Dušan S. „Weather Radar Polarimetry–Trends Toward Operational Applications“. Bulletin of the American Meteorological Society 77, Nr. 7 (01.07.1996): 1529–34. http://dx.doi.org/10.1175/1520-0477-77.7.1529.

Der volle Inhalt der Quelle

Annotation:

This is a version of a speech presented at the 27th Conference on Radar Meteorology. Relative advantages of polarimetry are contrasted with the advantages accrued by the introduction of radar into meteorology and by the addition of Doppler measurements. A description of present interests as perceived by the author follows, and possible future trends are suggested.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Rutledge, Steven A., und V. Chandrasekar. „Some Educational Innovations in Radar Meteorology“. Meteorological Monographs 30, Nr. 52 (August 2003): 259. http://dx.doi.org/10.1175/0065-9401(2003)030<0259:seiirm>2.0.co;2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Meischner, Peter. „First European conference on radar meteorology“. Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere 25, Nr. 10-12 (Januar 2000): 811. http://dx.doi.org/10.1016/s1464-1909(00)00106-4.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Martin, William J., und Alan Shapiro. „Discrimination of Bird and Insect Radar Echoes in Clear Air Using High-Resolution Radars“. Journal of Atmospheric and Oceanic Technology 24, Nr. 7 (01.07.2007): 1215–30. http://dx.doi.org/10.1175/jtech2038.1.

Der volle Inhalt der Quelle

Annotation:

Abstract The source of clear-air reflectivity from operational and research meteorological radars has been a subject of much debate and study over the entire history of radar meteorology. Recent studies have suggested that bird migrations routinely contaminate wind profiles obtained at night, while historical studies have suggested insects as the main source of such nocturnal clear-air echoes. This study analyzes two cases of nocturnal clear-air return using data from operational Weather Surveillance Radar-1988 Doppler (WSR-88D) and X- and W-band research radars. The research radars have sufficient resolution to resolve the echo as point targets in some cases. By examining the radar cross section of the resolved point targets, and by determining the target density, it is found for both cases of nocturnal clear-air echoes that the targets are almost certainly insects. The analysis of the dependence of the echo strength on radar wavelength also supports this conclusion.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

Areerachakul, Nathaporn, Sethakarn Prongnuch, Peeranat Longsomboon und Jaya Kandasamy. „Quantitative Precipitation Estimation (QPE) Rainfall from Meteorology Radar over Chi Basin“. Hydrology 9, Nr. 10 (11.10.2022): 178. http://dx.doi.org/10.3390/hydrology9100178.

Der volle Inhalt der Quelle

Annotation:

This study of the Quantitative Estimation Precipitation (QEP) of rainfall, detected by two Meteorology Radars over Chi Basin, North-east Thailand, used data from the Thai Meteorological Department (TMD). The rainfall data from 129 rain gauge stations in the Chi Basin area, covering a period of two years, was also used. The study methodology consists of: firstly, deriving the QPE between radar and rainfall based on meteorological observations using the Marshall Palmer Stratiform, the Summer Deep Convection, and Regression Model and calibrating with rain gauge station data; secondly, Bias Correction using statistical method; thirdly, determining spatial variation using three methods, namely Kriging, Inverse Distance Weight (IDW), and the Minimum Curvature Method. The results of the study demonstrated the accuracy of estimating precipitation using meteorological radar. Estimated precipitation compared against an equivalent of 2 years of rain station measurement had a probability of detection (POD) of 0.927, where a value of 1 indicated perfect agreement, demonstrating the effectiveness of the method used to calibrate the radar data. The bias correction method gave high accuracy compared with measured rainfall. Furthermore, of the spatial estimation of rainfall methods, the Kriging methodology showed the best fit between estimation of rainfall distribution and measured rainfall distribution. Therefore, the results of this study showed that the rainfall estimation, using data from a meteorology radar, has good accuracy and can be useful, especially in areas where it is not possible to install and operate rainfall measurement stations, such as in heavily forested areas and/or in steep terrain. Additionally, good accuracy rainfall data derived from radar data can be integrated with other data used for water management and natural disasters for applications to reduce economic losses, as well as losses of life and property.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

Ogawa, T., S. Nozawa, M. Tsutsumi, N. F. Arnold, N. Nishitani, N. Sato und A. S. Yukimatu. „Arctic and Antarctic polar mesosphere summer echoes observed with oblique incidence HF radars: analysis using simultaneous MF and VHF radar data“. Annales Geophysicae 22, Nr. 12 (22.12.2004): 4049–59. http://dx.doi.org/10.5194/angeo-22-4049-2004.

Der volle Inhalt der Quelle

Annotation:

Abstract. Polar mesosphere summer echoes (PMSEs) have been well studied using vertical incidence VHF radars at northern high-latitudes. In this paper, two PMSE events detected with the oblique incidence SuperDARN HF radars at Hankasalmi, Finland (62.3° N) and Syowa Station, Antarctica (69.0° S), are analyzed, together with simultaneous VHF and medium-frequency (MF) radar data. Altitude resolutions of the HF radars in the mesosphere and the lower thermosphere are too poor to know exact PMSE altitudes. However, a comparison of Doppler velocity from the HF radar and neutral wind velocity from the MF radar shows that PMSEs at the HF band appeared at altitudes within 80-90km, which are consistent with those from previous vertical incidence HF-VHF radar results. The HF-VHF PMSE occurrences exhibit a semidiurnal behavior, as observed by other researchers. It is found that in one event, PMSEs occurred when westward semidiurnal winds with large amplitude at 85-88km altitudes attained a maximum. When the HF-VHF PMSEs were observed at distances beyond 180km from MF radar sites, the MF radars detected no appreciable signatures of echo enhancement. Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

Worthington, R. M. „Asymmetry of atmospheric microstructure over synoptic scales“. Annales Geophysicae 19, Nr. 8 (31.08.2001): 921–24. http://dx.doi.org/10.5194/angeo-19-921-2001.

Der volle Inhalt der Quelle

Annotation:

Abstract. Distortions are often seen in the angular distribution of echo-power from VHF wind-profiling radars, suggesting that thin stable layers, within the air flow, are distorted and tilted from horizontal. In vertical shear of the horizontal wind, the distribution of the layer tilt angles becomes skewed. A case study using six days of VHF radar data and synoptic charts above western Europe indicates that this asymmetry of atmospheric microstructure can exist throughout the troposphere and lower stratosphere, above and below the jet wind maximum, over horizontal scales of thousands of kilometres.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; synoptic-scale meteorology; turbulence).

APA, Harvard, Vancouver, ISO und andere Zitierweisen

11

Ghosh, A. K., V. Siva Kumar, K. Kishore Kumar und A. R. Jain. „VHF radar observation of atmospheric winds, associated shears and C2n at a tropical location: interdependence and seasonal pattern“. Annales Geophysicae 19, Nr. 8 (31.08.2001): 965–73. http://dx.doi.org/10.5194/angeo-19-965-2001.

Der volle Inhalt der Quelle

Annotation:

Abstract. The turbulence refractivity structure constant (C2n ) is an important parameter of the atmosphere. VHF radars have been used extensively for the measurements of C2n. Presently, most of such observations are from mid and high latitudes and only very limited observations are available for equatorial and tropical latitudes. Indian MST radar is an excellent tool for making high-resolution measurements of atmospheric winds, associated shears and turbulence refractivity structure constant (C2n). This radar is located at Gadanki (13.45° N, 79.18° E), a tropical station in India. The objective of this paper is to bring out the height structure of C2n for different seasons using the long series of data (September 1995 – August 1999) from Indian MST radar. An attempt is also made to understand such changes in the height structure of C2n in relation to background atmospheric parameters such as horizontal winds and associated shears. The height structure of C2n, during the summer monsoon and post-monsoon season, shows specific height features that are found to be related to Tropical Easterly Jet (TEJ) winds. It is important to examine the nature of the radar back-scatterers and also to understand the causative mechanism of such scatterers. Aspect sensitivity of the received radar echo is examined for this purpose. It is observed that radar back-scatterers at the upper tropospheric and lower stratospheric heights are more anisotropic, with horizontal correlation length of 10–20 m, as compared to those observed at lower and middle tropospheric heights.Key words. Meteorology and atmospheric dynamics (climatology; tropical meteorology; turbulence)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

12

Steiner, Matthias, und Peter F. Meischner. „The 30th International Conference on Radar Meteorology“. Bulletin of the American Meteorological Society 83, Nr. 11 (November 2002): 1649–56. http://dx.doi.org/10.1175/bams-83-11-1649.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

13

Steiner, Matthias, und Peter F. Meischner. „The 30th International Conference on Radar Meteorology“. Bulletin of the American Meteorological Society 83, Nr. 11 (November 2002): 1649–56. http://dx.doi.org/10.1175/bams-83-11-1649(2002)083<1649:ticorm>2.3.co;2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

14

Cao, Qing, Guifu Zhang und Ming Xue. „A Variational Approach for Retrieving Raindrop Size Distribution from Polarimetric Radar Measurements in the Presence of Attenuation“. Journal of Applied Meteorology and Climatology 52, Nr. 1 (Januar 2013): 169–85. http://dx.doi.org/10.1175/jamc-d-12-0101.1.

Der volle Inhalt der Quelle

Annotation:

AbstractThis study presents a two-dimensional variational approach to retrieving raindrop size distributions (DSDs) from polarimetric radar data in the presence of attenuation. A two-parameter DSD model, the constrained-gamma model, is used to represent rain DSDs. Three polarimetric radar measurements—reflectivity ZH, differential reflectivity ZDR, and specific differential phase KDP—are optimally used to correct for the attenuation and retrieve DSDs by taking into account measurement error effects. Retrieval results with simulated data demonstrate that the proposed algorithm performs well. Applications to real data collected by the X-band Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) radars and the C-band University of Oklahoma–Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME) also demonstrate the efficacy of this approach.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

15

Manson, A. H., C. E. Meek, C. M. Hall, S. Nozawa, N. J. Mitchell, D. Pancheva, W. Singer und P. Hoffmann. „Mesopause dynamics from the scandinavian triangle of radars within the PSMOS-DATAR Project“. Annales Geophysicae 22, Nr. 2 (01.01.2004): 367–86. http://dx.doi.org/10.5194/angeo-22-367-2004.

Der volle Inhalt der Quelle

Annotation:

Abstract. The "Scandinavian Triangle" is a unique trio of radars within the DATAR Project (Dynamics and Temperatures from the Arctic MLT (60–97km) region): Andenes MF radar (69°N, 16°E); Tromsø MF radar (70°N, 19°E) and Esrange "Meteor" radar (68°N, 21°E). The radar-spacings range from 125-270km, making it unique for studies of wind variability associated with small-scale waves, comparisons of large-scale waves measured over small spacings, and for comparisons of winds from different radar systems. As such it complements results from arrays having spacings of 25km and 500km that have been located near Saskatoon. Correlation analysis is used to demonstrate a speed bias (MF smaller than the Meteor) between the radar types, which varies with season and altitude. Annual climatologies for the year 2000 of mean winds, solar tides, planetary and gravity waves are presented, and show indications of significant spatial variability across the Triangle and of differences in wave characteristics from middle latitudes. Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides: instrument and techniques)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

16

Pilorz, Wojciech, und Philip Ciaramella. „Preliminary reflectivity analysis of severe convective events in in the proximity of Goczałkowice-Zdrój, Poland“. Environmental & Socio-economic Studies 7, Nr. 2 (01.06.2019): 32–38. http://dx.doi.org/10.2478/environ-2019-0010.

Der volle Inhalt der Quelle

Annotation:

Abstract At the beginning of 2018, the X-band radar in Goczałkowice-Zdrój (southern Poland) was launched. The scanning area corresponds with the scanning area of the POLRAD C-band radar system operated by the Polish Institute of Meteorology and Water Management. New opportunities were created for imaging phenomena by comparing some reflectivity features from C-Band radar and X-Band local weather radar. Moreover, some of the signatures located in the lower troposphere can be better documented by local X-Band radar. Firstly, reports from the ESWD (European Severe Weather Database) have been thoroughly analysed. All severe weather reports in the proximity of Goczałkowice-Zdrój (100-km radius) were gathered into one-storm events. Then the reflectivity from both radars was analysed to determine which reflectivity patterns occurred and when. X-band radars are known from the more intensive attenuation of the radar beam by the scatterers located closer to the radar, thus it is essential to compare capabilities of these two different radar systems. It was found that the average reflectivity for all convective incidents is higher when using POLRAD C-band radar data. In some events it was possible to find some spatial reflectivity signatures. We also discuss other reflectivity signatures previously described in the literature. Taking into account stronger Goczałkowice-Zdrój X-band radar attenuation, we suggest that some of these should be reviewed by reduction of the reflectivity thresholds.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

17

Hubbert, J. C., und V. N. Bringi. „Specular null polarization theory: applications to radar meteorology“. IEEE Transactions on Geoscience and Remote Sensing 34, Nr. 4 (Juli 1996): 859–73. http://dx.doi.org/10.1109/36.508403.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

18

Rosyadi, Fahmi, Masbah R. T. Siregar und Abdul Multi. „INTEGRASI DISTRIBUSI DATA RADAR MENGGUNAKAN TEKNOLOGI BLOCKCHAIN DAN KRIPTOGRAF“. SAINSTECH: JURNAL PENELITIAN DAN PENGKAJIAN SAINS DAN TEKNOLOGI 32, Nr. 3 (18.07.2022): 1–11. http://dx.doi.org/10.37277/stch.v32i3.1343.

Der volle Inhalt der Quelle

Annotation:

Abstract Currently, radar is widely used in various fields such as meteorology, military, police, shipping, aviation, agriculture, disaster, and research. Meanwhile, currently the use of radar is still in the form of sectoral, partial, and fragmented so that the use of radar data is only internal. With Indonesia's geographical condition which is very broad and the integration and distribution of radar data has not been maximized, this has resulted in the lack of geographic area of Indonesia that is reached by radar. The use or exchange of radar data still uses client-server-based information technology, and with centralized storage which has information security and privacy risk factors that are vulnerable to being misused or exploited. In addition, there is the possibility of data loss which makes it difficult to get data back, even when you have implemented a backup system with cloud or other protection, there is still a risk of complete data loss when compared to implementing a decentralized platform. Therefore, it is necessary to integrate and distribute radar data with a decentralized platform so that the radar data is not sectoral, partial, and fragmented. The integration and distribution of radar data will later be able to maximize the use of cross-field radar so that one radar can be used more optimally for all fields including meteorology, military, police, shipping, aviation, agriculture, disaster, and research. One of the technologies that can be used for the integration of radar distribution is blockchain and cryptography. Keywords: Radar, Blockchain, Cryptography.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

19

Hocking, W. K. „A new approach to momentum flux determinations using SKiYMET meteor radars“. Annales Geophysicae 23, Nr. 7 (14.10.2005): 2433–39. http://dx.doi.org/10.5194/angeo-23-2433-2005.

Der volle Inhalt der Quelle

Annotation:

Abstract. The current primary radar method for determination of atmospheric momentum fluxes relies on multiple beam studies, usually using oppositely directed coplanar beams. Generally VHF and MF radars are used, and meteor radars have never been successfully employed. In this paper we introduce a new procedure that can be used for determination of gravity wave fluxes down to time scales of 2-3h, using the SKiYMET meteor radars. The method avoids the need for beam forming, and allows simultaneous determination of the three components of the wind averaged over the radar volume, as well as the variance and flux components , where refers to the fluctuating eastward wind, refers to the fluctuating northward wind, and refers to the fluctuating vertical wind. Data from radars in New Mexico and Resolute Bay are used to illustrate the data quality, and demonstrate theoretically expected seasonal forcing. Keywords. Meteorology and atmospheric dynamics (Middle atmosphere dynamics; Waves and tides; Climatology)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

20

Ogawa, T., N. F. Arnold, S. Kirkwood, N. Nishitani und M. Lester. „Finland HF and Esrange MST radar observations of polar mesosphere summer echoes“. Annales Geophysicae 21, Nr. 4 (30.04.2003): 1047–55. http://dx.doi.org/10.5194/angeo-21-1047-2003.

Der volle Inhalt der Quelle

Annotation:

Abstract. Peculiar near range echoes observed in summer with the SuperDARN HF radar in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant ranges of 105–250 km for about 100 min. Interferometer measurements indicate that the echoes are returned from 80–100 km altitudes with elevation angles of 20°–60°. Echo power (< 16 dB), Doppler velocity (between –30 and + 30 ms-1) and spectral width (< 60 ms-1) fluctuate with periods of several to 20 min, perhaps due to short–period atmospheric gravity waves. When the HF radar detected the echoes, a vertical incidence MST radar, located at Esrange in Sweden (650 km north of the HF radar site), observed polar mesosphere summer echoes (PMSE) at altitudes of 80–90 km. This fact suggests that the near range HF echoes are PMSE at HF band, although both radars did not probe a common volume. With increasing radar frequency, HF echo ranges are closer to the radar site and echo power becomes weaker. Possible mechanisms to explain these features are discussed.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides; instruments and techniques)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

21

Hocking, W. K., und J. Röttger. „The structure of turbulence in the middle and lower atmosphere seen by and deduced from MF, HF and VHF radar, with special emphasis on small-scale features and anisotropy“. Annales Geophysicae 19, Nr. 8 (31.08.2001): 933–44. http://dx.doi.org/10.5194/angeo-19-933-2001.

Der volle Inhalt der Quelle

Annotation:

Abstract. An overview of the turbulent structures seen by MF, HF and VHF radars in the troposphere, stratosphere and mesosphere is presented, drawing on evidence from previous radar measurements, in situ studies, laboratory observations, observations at frequencies other than those under focus, and modelling studies. We are particularly interested in structures at scales less than one radar pulse length, and smaller than the beam width, and especially the degree of anisotropy of turbulence at these scales. Previous radar observations are especially important in regard to the degree of anisotropy, and we highlight the role that these studies have had in furthering our understanding in this area. The contrasts and similarities between the models of anisotropic turbulence and specular reflection are considered. The need for more intense studies of anisotropy at MF, HF and VHF is especially highlighted, since this is an area in which these radars can make important contributions to the understanding of atmospheric turbulence.Key words. Meteorology and atmospheric dynamics (turbulence) – Atmospheric composition and structure (instruments and techniques) – History of geophysics (atmospheric sciences)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

22

Arnold, N. F., T. B. Jones, T. R. Robinson, A. J. Stocker und J. A. Davies. „Validation of the CUTLASS HF radar gravity wave observing capability using EISCAT CP-1 data“. Annales Geophysicae 16, Nr. 10 (31.10.1998): 1392–99. http://dx.doi.org/10.1007/s00585-998-1392-z.

Der volle Inhalt der Quelle

Annotation:

Abstract. Quasi-periodic fluctuations in the returned ground-scatter power from the SuperDARN HF radars have been linked to the passage of medium-scale gravity waves. We have applied a technique that extracts the first radar range returns from the F-region to study the spatial extent and characteristics of these waves in the CUTLASS field-of-view. Some ray tracing was carried out to test the applicability of this method. The EISCAT radar facility at Tromsø is well within the CUTLASS field-of-view for these waves and provides a unique opportunity to assess independently the ability of the HF radars to derive gravity wave information. Results from 1st March, 1995, where the EISCAT UHF radar was operating in its CP-1 mode, demonstrate that the radars were in good agreement, especially if one selects the electron density variations measured by EISCAT at around 235 km. CUTLASS and EISCAT gravity wave observations complement each other; the former extends the spatial field of view considerably, whilst the latter provides detailed vertical information about a range of ionospheric parameters.Key words. Ionosphere (ionosphere – atmosphere interactions) · Meteorology and atmospheric dynamics (thermospheric dynamics) · Radio science (ionospheric propagations)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

23

Satheesan, K., und B. V. Krishna Murthy. „A study of tropical tropopause using MST radar“. Annales Geophysicae 23, Nr. 7 (14.10.2005): 2441–48. http://dx.doi.org/10.5194/angeo-23-2441-2005.

Der volle Inhalt der Quelle

Annotation:

Abstract. Using the MST radar data of vertical wind, the characteristics of the tropical tropopause, following four different definitions, depending on 1) temperature lapse rate, 2) cold point, 3) convective outflow and 4) potential temperature lapse rate minimum, are studied. From the vertical wind data of the radar, the altitude profiles of temperature and horizontal divergence are derived, from which the tropopause levels corresponding to i) the lapse rate ii) cold point iii) convective outflow level and iv) potential temperature lapse rate minimum are determined. The convective outflow level and hence the convective tropopause altitude is determined, for the first time using the MST radar data. The tropopause altitudes and temperatures obtained following the four definitions are compared on a day-to-day basis for the summer and winter seasons. Winter and summer differences in the tropopause altitude and temperature are also studied. Keywords. Meteorology and atmospheric dynamics (convective process; middle atmosphere dynamics; tropical meteorology)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

24

Van Zandt, T. E. „A brief history of the development of wind-profiling or MST radars“. Annales Geophysicae 18, Nr. 7 (31.07.2000): 740–49. http://dx.doi.org/10.1007/s00585-000-0740-4.

Der volle Inhalt der Quelle

Annotation:

Abstract. The history of the development of the wind-profiling or MST radar technique is reviewed from its inception in the late 1960s to the present. Extensions of the technique by the development of boundary-layer radars and the radio-acoustic sounding system (RASS) technique to measure temperature are documented. Applications are described briefly, particularly practical applications to weather forecasting, with data from networks of radars, and scientific applications to the study of rapidly varying atmospheric phenomena such as gravity waves and turbulence.Key words: Meteorology and atmospheric dynamics (instruments and techniques) · Radio science (remote sensing; instruments and techniques)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

25

Fathauer, Ted. „First Doppler weather radar studies of the wintertime meteorology of interior Alaska“. Polar Record 31, Nr. 178 (Juli 1995): 287–96. http://dx.doi.org/10.1017/s0032247400013838.

Der volle Inhalt der Quelle

Annotation:

AbstractA weather surveillance radar model 88–D (WSR–88D) was installed on Pedro Dome, a hill approximately 23 km north of Fairbanks, in the late summer of 1993. The radar commenced operation in September 1993. The Fairbanks radar was the first Doppler weather radar installed in Alaska and the farthest north modern weather radar in the world. During the winter of 1993–1994 the Fairbanks radar gave meteorologists their first detailed look at the meteorology of interior Alaska. The area encompassed by the radar's field of view includes complex terrain—both large flatlands and highlands reaching more than 1 km above the valley floor.This new opportunity yielded some surprises. Foremost among them is the unanticipated complexity and small scale of meteorological processes during the winter in an Arctic region. Sequences of composite reflectivity show a consistent pattern of considerable change over time spans of 10–30 minutes, as well as large variance of reflectivity over distances of 10 km or less. The reflectivity patterns are often composed of banded structures, with small granular areas of higher echo return embedded within. The large-scale bands can be correlated to synoptic scale patterns of wind aloft, while the smaller cellular structures in the bands may be partly attributed to upslope flow over hills. However, some areas of strong radar return appear to have no relation to topography. The high stability of the airmass over Fairbanks most of the winter would appear to rule out convection. Gravity waves at the top of strong temperature inversions are a possible cause. It is presumed that other processes are at work in this scene, and they remain unexplained.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

26

Kafando, P., und M. Petitdidier. „An attempt to calibrate the UHF strato-tropospheric radar at Arecibo using NexRad radar and disdrometer data“. Annales Geophysicae 22, Nr. 12 (22.12.2004): 4025–34. http://dx.doi.org/10.5194/angeo-22-4025-2004.

Der volle Inhalt der Quelle

Annotation:

Abstract. The goal of this paper is to present a methodology to calibrate the reflectivity of the UHF Strato-Tropospheric (ST) radar located at NAIC in Puerto Rico. The UHF lower relevant altitude is at 5.9km, the melting layer being at around 4.8km. The data used for the calibration came from the observations of clouds, carried out with Strato-Tropospheric dual-wavelength (UHF and VHF) radars and a disdrometer; those instruments being located on the NAIC site in Arecibo, Puerto Rico. The National Weather Service operates other instruments like the radiosondes and the NexRad Radar in other sites. The proposed method proceeds in two steps. The first consists of the comparison between the NexRad reflectivity and the reflectivity computed from the drop size distributions measured by the disdrometer for one day with a noticeable rainfall rate. In spite of the distance of both instruments, the agreement between the reflectivities of both instruments is enough good to be used as a reference for the UHF ST radar. The errors relative at each data set is found to be 2.75dB for the disdrometer and 4dB for the NexRad radar, following the approach of Hocking et al. (2001). The inadequacy between the two sampled volume is an important contribution in the errors. The second step consists of the comparison between the NexRad radar reflectivity and the UHF non-calibrated reflectivity at the 4 altitudes of common observations during one event on 15 October 1998. Similar features are observed and a coefficient is deduced. An offset around 4.7dB is observed and the correlation factor lies between 0.628 and 0.730. According to the errors of the data sets, the precision on the calibration is of the order of 2dB. This method works only when there are precipitation hydrometeors above the NAIC site. However, the result of the calibration could be applied to other data obtained during the campaign, the only constraint being the same value of the transmitter power. Key words. Meteorology and atmospheric dynamics (tropical meteorology; remote sensing; instruments and techniques)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

27

Podhorský, Dušan, und Peter Guba. „History of remote-sensing methods in meteorology, cloud physics and nowcasting in Slovakia over the period 1965–1990“. Contributions to Geophysics and Geodesy 44, Nr. 1 (01.03.2014): 79–94. http://dx.doi.org/10.2478/congeo-2014-0005.

Der volle Inhalt der Quelle

Annotation:

Abstract A brief overview of building the radar and satellite meteorology in Slovakia over the period 1965-1990 and application of dispatching locators of PAR, SRE and RSR types for studying the evolution of convective cells is given. Further, the conception and implementation of a meteorological radar network in Slovakia, the algorithms for recognition of clouds and phenomena related to the parameters of radioecho are reviewed. The development of a new laser radar (LIDAR) and the application of a prototype meteorological radar with the TESLA RM-3 controlled polarizer are described.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

28

Kishore, Pangaluru, Isabella Velicogna, Tyler C. Sutterley, Yara Mohajerani, Enrico Ciracì und Gummadipudi Nagasai Madhavi. „A case study of mesospheric planetary waves observed over a three-radar network using empirical mode decomposition“. Annales Geophysicae 36, Nr. 3 (21.06.2018): 925–36. http://dx.doi.org/10.5194/angeo-36-925-2018.

Der volle Inhalt der Quelle

Annotation:

Abstract. In this paper an attempt is made to study equatorial Kelvin waves using a network of three radars: Kototabang (0.204∘ S, 100.320∘ E) meteor radar, Pameungpeuk (7.646∘ S, 107.688∘ E) medium-frequency radar, and Pontianak (0.003∘ S, 109.367∘ E) medium-frequency radar. We have used the continuous data gathered from the three radars during April–May 2010. Empirical mode decomposition (EMD), Lomb–Scargle periodogram (LSP) analysis, and wavelet techniques are used to study the temporal and altitude structures of planetary waves. Here, we used a novel technique called EMD to extract the planetary waves from wind data. The planetary waves of ∼ 6.5 and ∼ 3.6 days periodicity are observed in all three radar stations with peak amplitudes of about 12 and 11 m s−1, respectively. The 3.6-day wave has an average vertical wavelength from the three radars of about 42 km. The 3.6- and 6.5-day planetary waves are particularly strong in the zonal wind component. We find that the two waves are present at the 84–94 km height region. The observed features of the 3.6- and 6.5-day waves at the three tropical-latitude stations show some correspondence with the results reported for the equatorial-latitude stations. Keywords. Electromagnetics (wave propagation) – history of geophysics (atmospheric sciences) – meteorology and atmospheric dynamics (middle atmosphere dynamics)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

29

Worthington, R. M., R. D. Palmer und S. Fukao. „Letter to the Editor: Complete maps of the aspect sensitivity of VHF atmospheric radar echoes“. Annales Geophysicae 17, Nr. 8 (31.08.1999): 1116–19. http://dx.doi.org/10.1007/s00585-999-1116-z.

Der volle Inhalt der Quelle

Annotation:

Abstract. Using the MU radar at Shigaraki, Japan (34.85°N, 136.10°E), we measure the power distribution pattern of VHF radar echoes from the mid-troposphere. The large number of radar beam-pointing directions (320) allows the mapping of echo power from 0° to 40° from zenith, and also the dependence on azimuth, which has not been achieved before at VHF wavelengths. The results show how vertical shear of the horizontal wind is associated with a definite skewing of the VHF echo power distribution, for beam angles as far as 30° or more from zenith, so that aspect sensitivity cannot be assumed negligible at any beam-pointing angle that most existing VHF radars are able to use. Consequently, the use of VHF echo power to calculate intensity of atmospheric turbulence, which assumes only isotropic backscatter at large beam zenith angles, will sometimes not be valid.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence; instruments and techniques)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

30

Réchou, A., V. Barabash, P. Chilson, S. Kirkwood, T. Savitskaya und K. Stebel. „Mountain wave motions determined by the Esrange MST radar“. Annales Geophysicae 17, Nr. 7 (31.07.1999): 957–70. http://dx.doi.org/10.1007/s00585-999-0957-9.

Der volle Inhalt der Quelle

Annotation:

Abstract. A European campaign of ground-based radar, lidar and optical measurements was carried out during the winter of 1996/1997 (28 December-2 February) to study lee waves in the northern part of Scandinavia. The participants operated ozone lidars, backscatter lidars and MST radars at ALOMAR/Andoya and Esrange/Kiruna, and an ALIS imaging system in Kiruna. The Andoya site was generally windward of the Scandinavian mountains, the Kiruna site on the leeward side. The goal of the experiment was to examine the influence of lee waves on the formation of Polar Stratospheric Clouds (PSCs). This paper studies the radar data from MST-radar ESRAD located at Esrange [68.°N, 21.°E], i.e. in the lee of the mountains. We present three cases where strong lee waves were observed: in one case they propagated upwards to the lower stratosphere and in the other two cases they were trapped or absorbed in the troposphere. We examine the local waves and the direction and strength of the local wind using the radar, the synoptic meteorological situation using weather maps (European Meteorological Bulletin) and the synoptic stratospheric temperatures using ECMWF data. We observed that waves propagate up to the stratosphere during frontal passages. When anticyclonic ridges are present, the propagation to the stratosphere is very weak. This is due to trapping of the waves at or below the tropopause. We also show that the radar data alone can be used to characterise the different weather conditions for the three cases studied (through the variation of the height of the tropopause). The synoptic stratospheric temperatures in the three cases were similar, and were above the expected threshold for PSC formation. Lidar and visual observation of PSCs and nacreous clouds, respectively, showed that these were present only in the case when the lee waves propagated up to the lower stratosphere.Key words. Atmospheric composition and structure (aerosols and particles) · Electromagnetic (wave propa- gation) · Meteorology and atmospheric dynamics (mesoscale meteorology)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

31

Rutledge, Steven A., Patrick C. Kennedy und David A. Brunkow. „Use of the CSU–CHILL Radar in Radar Meteorology Education at Colorado State University“. Bulletin of the American Meteorological Society 74, Nr. 1 (Januar 1993): 25–31. http://dx.doi.org/10.1175/1520-0477(1993)074<0025:uotcri>2.0.co;2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

32

Frame, D. J., B. N. Lawrence, G. J. Fraser und M. D. Burrage. „A comparison between mesospheric wind measurements made near Christchurch (44°S, 173°E) using the high resolution doppler imager (HRDI) and a medium frequency (MF) radar“. Annales Geophysicae 18, Nr. 5 (31.05.2000): 555–65. http://dx.doi.org/10.1007/s00585-000-0555-3.

Der volle Inhalt der Quelle

Annotation:

Abstract. We report on the comparison of winds measured by a medium frequency (MF) radar near Christchurch, New Zealand, and by the high resolution doppler imager (HRDI). Previous comparisons have demonstrated that there can be significant differences in the winds obtained by the two techniques, and our results are no different. However, these data show relatively good agreement in the meridional direction, but large differences in the zonal direction, where the radar is regularly measuring the zonal wind as too easterly. To do the comparison, overpasses from the satellite must be obtained when it is close to the radar site. The radar data are averaged in time around the overpass because we know the radars sample phenomena which have spatial and temporal scales which make them invisible to HRDI. There are a limited number of overpass comparisons which limit our confidence in these results, but a detailed analysis of these data show that the proximity of the overpass is often an important factor in the differences obtained. Other factors examined include the influence of the local time of the overpass, and the amount of radar data averaged around the overpass time.Key words: Atmospheric composition and structure (instruments and techniques) · Meteorology and atmospheric dynamics (middle atmosphere dynamics; instruments and techniques)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

33

Campistron, B., G. Despaux, M. Lothon, V. Klaus, Y. Pointin und M. Mauprivez. „A partial 45 MHz sky temperature map obtained from the observations of five ST radars“. Annales Geophysicae 19, Nr. 8 (31.08.2001): 863–71. http://dx.doi.org/10.5194/angeo-19-863-2001.

Der volle Inhalt der Quelle

Annotation:

Abstract. A sky temperature map at 45 MHz covering declination between + 30° and + 60° is presented. The sampling in right ascension is 20 min (~5°) and 2° in declination in most of the map. The originality of the work was to use cosmic emission measurements from five VHF Stratosphere-Troposphere (ST) radars collected during long periods of routine meteorological surveys. This map, which has an accuracy in temperature of about 600 K, is intended first for radar reflectivity calibration and system performance monitoring. The presence of two strong radio sources, Cassiopeia A and Cygnus A, can also serve as the verification of the beam diagram, beam width, and beam pointing direction of the antenna. Finally, this work is an attempt to show the potentiality of ST radar for astronomical purposes.Key words. Meteorology and atmospheric dynamics (instruments and techniques) – Radio science (radio astronomy)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

34

Griffin, Casey B., David J. Bodine und Robert D. Palmer. „Kinematic and Polarimetric Radar Observations of the 10 May 2010, Moore–Choctaw, Oklahoma, Tornadic Debris Signature“. Monthly Weather Review 145, Nr. 7 (Juli 2017): 2723–41. http://dx.doi.org/10.1175/mwr-d-16-0344.1.

Der volle Inhalt der Quelle

Annotation:

Tornadoes are capable of lofting large pieces of debris that present irregular shapes, near-random orientations, and a wide range of dielectric constants to polarimetric radars. The unique polarimetric signature associated with lofted debris is called the tornadic debris signature (TDS). While ties between TDS characteristics and tornado- and storm-scale kinematic processes have been speculated upon or investigated using photogrammetry and single-Doppler analyses, little work has been done to document the three-dimensional wind field associated with the TDS. Data collected by the Oklahoma City, Oklahoma (KTLX), and Norman, Oklahoma (KOUN), WSR-88D S-band radars as well as the University of Oklahoma’s (OU) Advanced Radar Research Center’s Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME) C-band radar are used to construct single- and dual-Doppler analyses of a tornadic supercell that produced an EF4 tornado near the towns of Moore and Choctaw, Oklahoma, on 10 May 2010. This study documents the spatial distribution of polarimetric radar variables and how each variable relates to kinematic fields such as vertical velocity and vertical vorticity. Special consideration is given to polarimetric signatures associated with subvortices within the tornado. An observation of negative differential reflectivity ([Formula: see text]) at the periphery of tornado subvortices is presented and discussed. Finally, dual-Doppler wind retrievals are compared to single-Doppler axisymmetric wind fields to illustrate the merits of each method.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

35

Griffin, Casey B., David J. Bodine und Robert Palmer. „Polarimetric Radar Observations of Simultaneous Tornadoes on 10 May 2010 near Norman, Oklahoma“. Monthly Weather Review 148, Nr. 2 (03.01.2020): 477–97. http://dx.doi.org/10.1175/mwr-d-19-0156.1.

Der volle Inhalt der Quelle

Annotation:

Abstract This study utilizes data collected by the University of Oklahoma Advanced Radar Research Center’s Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME) C-band radar as well as the federal KTLX and KOUN WSR-88D S-band radars to study a supercell that simultaneously produced a long-track EF-4 tornado and an EF-2 landspout tornado (EF indicates the enhanced Fujita scale) near Norman, Oklahoma, on 10 May 2010. Contrasting polarimetric characteristics of two tornadoes over similar land cover but with different intensities are documented. Also, the storm-scale sedimentation of debris within the supercell is investigated, which includes observations of rotation and elongation of a tornadic debris signature with height. A dual-wavelength comparison of debris at S and C bands is performed. These analyses indicate that lofted debris within the tornado was larger than debris located outside the damage path of the tornado and that debris size outside the tornado increased with height, likely as the result of centrifuging. Profiles of polarimetric variables were observed to become more vertically homogeneous with time.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

36

Hall, C. M. „On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion“. Annales Geophysicae 20, Nr. 11 (30.11.2002): 1857–62. http://dx.doi.org/10.5194/angeo-20-1857-2002.

Der volle Inhalt der Quelle

Annotation:

Abstract. By measuring fading times of radar echoes from underdense meteor trails, it is possible to deduce the ambipolar diffusivities of the ions responsible for these radar echoes. It could be anticipated that these diffusivities increase monotonically with height akin to neutral viscosity. In practice, this is not always the case. Here, we investigate the capability of neutral turbulence to affect the meteor trail diffusion rate.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

37

Méri, Ladislav, Ladislav Gaál, Juraj Bartok, Martin Gažák, Martin Gera, Marián Jurašek und Miroslav Kelemen. „Improved Radar Composites and Enhanced Value of Meteorological Radar Data Using Different Quality Indices“. Sustainability 13, Nr. 9 (09.05.2021): 5285. http://dx.doi.org/10.3390/su13095285.

Der volle Inhalt der Quelle

Annotation:

Radar measurements are inherently affected by various meteorological and non-meteorological factors that may lead to a degradation of their quality, and the unwanted effects are also transferred into composites, i.e., overlapping images from different radars. The paper was aimed at answering the research question whether we could create ‘cleaner’ radar composites without disturbing features, and if yes, how the operational practice could take advantage of the improved results. To achieve these goals, the qRad and qPrec software packages, based on the concept of quality indices, were used. The qRad package estimates the true quality of the C-band radar volume data using various quality indices and attempts to correct some of the adverse effects on the measurements. The qPrec package uses a probabilistic approach to estimate precipitation intensity, based on heterogeneous input data and quality-based outputs of the qRad software. The advantages of the qRad software are improved radar composites, which offer benefits, among others, for aviation meteorology. At the same time, the advantages of the qPrec software are manifested through improved quantitative precipitation estimation, which can be translated into hydrological modeling or climatological precipitation mapping. Beyond this, the developed software indirectly contributes to sustainability and environmental protection—for instance, by enabling fuel savings due to the more effective planning of flight routes or avoiding runway excursions due to information on the increased risk of aquaplaning.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

38

Teshiba, M., H. Hashiguchi, S. Fukao und Y. Shibagaki. „Typhoon 9707 observations with the MU radar and L-band boundary layer radar“. Annales Geophysicae 19, Nr. 8 (31.08.2001): 925–31. http://dx.doi.org/10.5194/angeo-19-925-2001.

Der volle Inhalt der Quelle

Annotation:

Abstract. Typhoon 9707 (Opal) was observed with the VHF-band Middle and Upper atmosphere (MU) radar, an L-band boundary layer radar (BLR), and a vertical-pointing C-band meteorological radar at the Shigaraki MU Observatory in Shiga prefecture, Japan on 20 June 1997. The typhoon center passed about 80 km southeast from the radar site. Mesoscale precipitating clouds developed due to warm-moist airmass transport from the typhoon, and passed over the MU radar site with easterly or southeasterly winds. We primarily present the wind behaviour including the vertical component which a conventional meteorological Doppler radar cannot directly observe, and discuss the relationship between the wind behaviour of the typhoon and the precipitating system. To investigate the dynamic structure of the typhoon, the observed wind was divided into radial and tangential wind components under the assumption that the typhoon had an axi-symmetric structure. Altitude range of outflow ascended from 1–3 km to 2–10 km with increasing distance (within 80–260 km range) from the typhoon center, and in-flow was observed above and below the outflow. Outflow and inflow were associated with updraft and downdraft, respectively. In the tangential wind, the maximum speed of counterclockwise winds was confirmed at 1–2 km altitudes. Based on the vertical velocity and the reflectivity obtained with the MU radar and the C-band meteorological radar, respectively, precipitating clouds, accompanied by the wind behaviour of the typhoon, were classified into stratiform and convective precipitating clouds. In the stratiform precipitating clouds, a vertical shear of radial wind and the maximum speed of counterclockwise wind were observed. There was a strong reflectivity layer called a ‘bright band’ around the 4.2 km altitude. We confirmed strong updrafts and down-drafts below and above it, respectively, and the existence of a relatively dry layer around the bright band level from radiosonde soundings. In the convective precipitating clouds, the regions of strong and weak reflectivities were well associated with those of updraft and downdraft, respectively.Key words. Meteorology and atmospheric dynamics (mesoscale meteorology; precipitation) Radio science (remote sensing)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

39

Sokol, Zbyněk, Jana Minářová und Petr Novák. „Classification of Hydrometeors Using Measurements of the Ka-Band Cloud Radar Installed at the Milešovka Mountain (Central Europe)“. Remote Sensing 10, Nr. 11 (23.10.2018): 1674. http://dx.doi.org/10.3390/rs10111674.

Der volle Inhalt der Quelle

Annotation:

In radar meteorology, greater interest is dedicated to weather radars and precipitation analyses. However, cloud radars provide us with detailed information on cloud particles from which the precipitation consists of. Motivated by research on the cloud particles, a vertical Ka-band cloud radar (35 GHz) was installed at the Milešovka observatory in Central Europe and was operationally measuring since June 2018. This study presents algorithms that we use to retrieve vertical air velocity (Vair) and hydrometeors. The algorithm calculating Vair is based on small-particle tracers, which considers the terminal velocity of small particles negligible and, thereby, Vair corresponds to the velocity of the small particles. The algorithm classifying hydrometeors consists of calculating the terminal velocity of hydrometeors and the vertical temperature profile. It identifies six hydrometeor types (cloud droplets, ice, and four precipitating particles: rain, graupel, snow, and hail) based on the calculated terminal velocity of hydrometeors, temperature, Vair, and Linear Depolarization Ratio. The results of both the Vair and the distribution of hydrometeors were found to be realistic for a thunderstorm associated with significant lightning activity on 1 June 2018.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

40

Kishore Kumar, K., A. R. Jain und D. Narayana Rao. „VHF/UHF radar observations of tropical mesoscale convective systems over southern India“. Annales Geophysicae 23, Nr. 5 (28.07.2005): 1673–83. http://dx.doi.org/10.5194/angeo-23-1673-2005.

Der volle Inhalt der Quelle

Annotation:

Abstract. Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E), a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other. Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes) – Radio science (Remote sensing)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

41

Arnold, N. F., P. A. Cook, T. R. Robinson, M. Lester, P. J. Chapman und N. Mitchell. „Comparison of D-region Doppler drift winds measured by the SuperDARN Finland HF radar over an annual cycle using the Kiruna VHF meteor radar“. Annales Geophysicae 21, Nr. 10 (31.10.2003): 2073–82. http://dx.doi.org/10.5194/angeo-21-2073-2003.

Der volle Inhalt der Quelle

Annotation:

Abstract. The SuperDARN chain of oblique HF radars has provided an opportunity to generate a unique climatology of horizontal winds near the mesopause at a number of high latitude locations, via the Doppler shifted echoes from sources of ionisation in the D-region. Ablating meteor trails form the bulk of these targets, but other phenomena also contribute to the observations. Due to the poor vertical resolution of the radars, care must be taken to reduce possible biases from sporadic-E layers and Polar Mesospheric Summer echoes that can affect the effective altitude of the geophysical parameters being observed. Second, there is strong theoretical and observational evidence to suggest that the radars are picking up echoes from the backward looking direction that will tend to reduce the measured wind strengths. The effect is strongly frequency dependent, resulting in a 20% reduction at 12 MHz and a 50% reduction at 10 MHz. A comparison of the climatologies observed by the Super-DARN Finland radar between September 1999 and September 2000 and that obtained from the adjacent VHF meteor radar located at Kiruna is also presented. The agreement between the two instruments was very good. Extending the analysis to the SuperDARN Iceland East radar indicated that the principles outlined above could be applied successfully to the rest of the SuperDARN network.Key words. Ionosphere (ionosphere-atmosphere interactions; instruments and techniques) – Meteorology and atmospheric dynamics (waves and tides)

APA, Harvard, Vancouver, ISO und andere Zitierweisen

42

Imran, Shaik, T. Anuradha und Ratnala Bharat. „Radar Based Precipitation Nowcasting Prediction by Using Deep Learning Techniques“. E3S Web of Conferences 405 (2023): 04003. http://dx.doi.org/10.1051/e3sconf/202340504003.

Der volle Inhalt der Quelle

Annotation:

Nowcasting is an emerging area in meteorology that focuses on accurately anticipating the severity of short-term rainfall for a particular location. It is essential to many facets of society. Owing to its significance, researchers are experimenting to predict short term rainfall using neural network approaches. This study analyses proposes a novel method of merging Convolutional Neural Network and Long Short-Term Memory neural networks on a radar echo dataset. The model was tested against a synthetic moving mnist dataset before applying on actual radar image dataset. Given the previous radar images, the model could successfully find future image sequences and obtained an accuracy of more than 90%.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

43

Islam, Tanvir, und Miguel A. Rico-Ramirez. „An overview of the remote sensing of precipitation with polarimetric radar“. Progress in Physical Geography: Earth and Environment 38, Nr. 1 (24.12.2013): 55–78. http://dx.doi.org/10.1177/0309133313514993.

Der volle Inhalt der Quelle

Annotation:

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.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

44

McCarthy, Nicholas, Hamish McGowan, Adrien Guyot und Andrew Dowdy. „Mobile X-Pol Radar: A New Tool for Investigating Pyroconvection and Associated Wildfire Meteorology“. Bulletin of the American Meteorological Society 99, Nr. 6 (Juni 2018): 1177–95. http://dx.doi.org/10.1175/bams-d-16-0118.1.

Der volle Inhalt der Quelle

Annotation:

AbstractThe process of pyroconvection occurs when fire-released heat, moisture, and/or aerosols induce or augment convection in the atmosphere. Prediction of pyroconvection presents a set of complex problems for meteorologists and wildfire managers. In particular, the turbulent characteristics of a pyroconvective plume exert bidirectional feedback on fire behavior, often with resulting severe impacts on life and property. Here, we present the motivation, field strategy, and initial results from the Bushfire Convective Plume Experiment, which through the use of mobile radar aims to quantify the kinematics of pyroconvection and its role in fire behavior. The case studies presented include world-first observations from two wildfires and one prescribed burn using the University of Queensland’s portable, dual-polarized X-band Doppler radar (UQ-XPOL). The initial analyses of reflectivity, Doppler winds, polarimetric variables, and spectrum width data provide insights into these relatively unexplored datasets within the context of pyroconvection. Weather radar data are supported by mesonet observations, time-lapse photography, airborne multispectral imaging, and spot-fire mapping. The ability to combine ground-validated fire intensity and progression at an hourly scale with quantitative data documenting the evolution of the convective plume kinematics at the scale of hundreds of meters represents a new capability for advancing our understanding of wildfires. The results demonstrate the suitability of portable, dual-polarized X-band Doppler radar to investigate pyroconvection and associated plume dynamics.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

45

Palmer, Robert D., David Bodine, Matthew Kumjian, Boonleng Cheong, Guifu Zhang, Qing Cao, Howard B. Bluestein, Alexander Ryzhkov, Tian-You Yu und Yadong Wang. „Observations of the 10 May 2010 Tornado Outbreak Using OU-PRIME: Potential for New Science with High-Resolution Polarimetric Radar“. Bulletin of the American Meteorological Society 92, Nr. 7 (01.07.2011): 871–91. http://dx.doi.org/10.1175/2011bams3125.1.

Der volle Inhalt der Quelle

Annotation:

A tornado outbreak occurred in central Oklahoma on 10 May 2010, including two tornadoes with enhanced Fujita scale ratings of 4 (EF-4). Tragically, three deaths were reported along with significant property damage. Several strong and violent tornadoes occurred near Norman, Oklahoma, which is a major hub for severe storms research and is arguably one of the best observed regions of the country with multiple Doppler radars operated by both the federal government and the University of Oklahoma (OU). One of the most recent additions to the radars in Norman is the high-resolution OU Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME). As the name implies, the radar is used as a platform for research and education in both science and engineering studies using polarimetric radar. To facilitate usage of the system by students and faculty, OU-PRIME was constructed adjacent to the National Weather Center building on the OU research campus. On 10 May 2010, several tornadoes formed near the campus while OU researchers were operating OU-PRIME in a sector scanning mode, providing polarimetric radar data with unprecedented resolution and quality. In this article, the environmental conditions leading to the 10 May 2010 outbreak will be described, an overview of OU-PRIME will be provided, and several examples of the data and possible applications will be summarized. These examples will highlight supercell polarimetric signatures during and after tornadogenesis, and they will describe how the polarimetric signatures are related to observations of reflectivity and velocity.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

46

Benarie, Michel. „Applications of weather radar wystems: A guide to uses of radar data in meteorology and hydrology“. Science of The Total Environment 101, Nr. 3 (Januar 1991): 293–94. http://dx.doi.org/10.1016/0048-9697(91)90046-h.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

47

Srivastava, R. C. „Applications of weather radar systems: A guide to uses of radar data in meteorology and hydrology“. Journal of Hydrology 130, Nr. 1-4 (Januar 1992): 408–9. http://dx.doi.org/10.1016/0022-1694(92)90122-c.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

48

Qi, Youcun, Zhe Zhang, Zhanfeng Zhao, Bong-Chul Seo und Huiqi Li. „An Editorial for the Special Issue “Processing and Application of Weather Radar Data”“. Remote Sensing 16, Nr. 11 (30.05.2024): 1967. http://dx.doi.org/10.3390/rs16111967.

Der volle Inhalt der Quelle

Annotation:

In 2019, the World Meteorological Organization (WMO) pointed out the following based on the statistics from 2007 to 2019: in natural disasters, 90% of losses are related to meteorology, of which heavy storms and floods account for more than 70% [...]

APA, Harvard, Vancouver, ISO und andere Zitierweisen

49

Bringi und Zrnic. „Polarization Weather Radar Development from 1970–1995: Personal Reflections“. Atmosphere 10, Nr. 11 (15.11.2019): 714. http://dx.doi.org/10.3390/atmos10110714.

Der volle Inhalt der Quelle

Annotation:

The modern era of polarimetric radar begins with radiowave propagation research starting in the early 1970s with applications to measurement and modeling of wave attenuation in rain and depolarization due to ice particles along satellite–earth links. While there is a rich history of radar in meteorology after World War II, the impetus provided by radiowave propagation requirements led to high-quality antennas and feeds. Our journey starts by describing the key institutions and personnel responsible for development of weather radar polarimetry. The early period was dominated by circularly polarized radars for propagation research and at S band (frequency near 3 GHz) for hail detection. By the mid to late 70s, a paradigm shift occurred which led to the dominance of linear polarizations with applications to slant path attenuation prediction as well as estimation of rain rates and inferences of precipitation physics. The period from the early 1980s to 1995 can be considered as the “golden” period of rapid research that brought in meteorologists, cloud physicists, and hydrologists. This article describes the evolution of this technology from the vantage point of the authors. Their personal reflections and “behind the scenes” descriptions offer a glimpse into the inner workings at several key institutions which cannot be found elsewhere.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

50

Probert-Jones, Richard. „Fundamental advances in radar meteorology in the United Kingdom, 1940-1965“. Weather 70, Nr. 4 (April 2015): 111–16. http://dx.doi.org/10.1002/wea.2457.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Zeitschriftenartikel zum Thema „Radar meteorology“

Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an