scholarly journals Resolute Bay VHF radar: A multipurpose tool for studies of tropospheric motions, middle atmosphere dynamics, meteor physics, and ionospheric physics

Radio Science ◽  
2001 ◽  
Vol 36 (6) ◽  
pp. 1839-1857 ◽  
Author(s):  
W. K. Hocking ◽  
M. Kelley ◽  
R. Rogers ◽  
W. O. J. Brown ◽  
D. Moorcroft ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Vhf Radar ◽  
Ionospheric Physics ◽  
Middle Atmosphere Dynamics ◽  
Resolute Bay

scholarly journals Seasonal variation of vertical eddy diffusivity in the troposphere, lower stratosphere and mesosphere over a tropical station

2001 ◽  
Vol 19 (8) ◽  
pp. 975-984 ◽  
Author(s):  
D. Narayana Rao ◽  
M. V. Ratnam ◽  
T. N. Rao ◽  
S. V. B. Rao
Keyword(s):  
Lower Stratosphere ◽  
Middle Atmosphere ◽  
Beam Width ◽  
Eddy Diffusivity ◽  
Lower Atmosphere ◽  
Spectral Parameters ◽  
Vhf Radar ◽  
June July ◽  
Vertical Eddy Diffusivity ◽  
Vertical Eddy

Abstract. Long-term VHF radar (53 MHz with 3° beam-width) observations at Gadanki (13.5° N, 79.2° E), India, during the period from September 1995 to August 1999 are used to study monthly, seasonal and annual medians of vertical eddy diffusivity, K in the troposphere, lower stratosphere and mesosphere. First, the spectral width contribution due to non-turbulent effects has been removed for further analysis and the monthly, seasonal medians of K are calculated. The monthly median of K in the troposphere shows maximum and minimum in June-July and November-December, respectively. In general, large values of K are seen up to 10 km and then decrease with height. Larger values of K are observed during monsoon and post-monsoon than in winter and summer. In general, the maximum and minimum values of the annual median of K (in logarithmic values) in the troposphere are found to be 0.25 and - 1.3 m2 s-1 respectively. In the mesosphere, the monthly median of K shows maximum and minimum during June-July and November-December, respectively, similar to the lower atmosphere. The value of K in the mesosphere becomes larger and it increases with height up to 75 km and again decreases above that height. The maximum values are seen during the summer, followed by equinoxes and a minimum during the winter. In general, the maximum and minimum values of K (in logarithmic values) are found to be 0.7 and 0.3 m2 s-1, respectively, in the mesosphere. A comparison of Doppler spectral parameters in different beam directions shows anisotropy in both signal-to- noise ratio (SNR) and spectral widths in the mesosphere, whereas it shows isotropy in SNR and anisotropy in the spectral widths in troposphere and lower stratosphere.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence; waves and tides)

scholarly journals Horizontally resolved structures of radar backscatter from polar mesospheric layers

2012 ◽  
Vol 10 ◽  
pp. 285-290 ◽  
Author(s):  
R. Latteck ◽  
W. Singer ◽  
M. Rapp ◽  
T. Renkwitz ◽  
G. Stober
Keyword(s):  
Middle Atmosphere ◽  
Beam Steering ◽  
Lower Thermosphere ◽  
The Arctic ◽  
Phased Array Antenna ◽  
Vhf Radar ◽  
The North ◽  
Expansion Stage ◽  
Arctic Atmosphere ◽  
High Flexibility

Abstract. The Leibniz-Institute of Atmospheric Physics in Kühlungsborn, Germany (IAP) installed a new powerful VHF radar on the North-Norwegian island Andøya (69.30° N, 16.04° E) from 2009 to 2011. The new Middle Atmosphere Alomar Radar System (MAARSY) replaces the existing ALWIN radar which has been in continuous operation on Andøya for more than 10 yr. MAARSY is a monostatic radar operated at 53.5 MHz with an active phased array antenna consisting of 433 Yagi antennas each connected to its own transceiver with independent control of frequency, phase and power of the transmitted signal. This arrangement provides a very high flexibility of beam forming and beam steering. It allows classical beam swinging operation as well as experiments with simultaneous multiple beams and the use of modern interferometric applications for improved studies of the Arctic atmosphere from the troposphere up to the lower thermosphere with high spatial-temporal resolution. The installation of the antenna was completed in August 2009. An initial expansion stage of 196 transceiver modules was installed in spring 2010, upgraded to 343 transceiver modules in December 2010 and the installation of the radar was completed in spring 2011. Beside standard observations of tropospheric winds and Polar Mesosphere Summer Echoes, multi-beam experiments using up to 91 beams quasi-simultaneously in the mesosphere have been carried out using the different expansion stages of the system during campaigns in 2010 and 2011. These results provided a first insight into the horizontal variability of Polar Mesosphere Summer and Winter Echoes in an area of about 80 km by 80 km with time resolutions between 3 and 9 min.

scholarly journals Radar efficiency and the calculation of decade-long PMSE backscatter cross-section for the Resolute Bay VHF radar

2009 ◽  
Vol 27 (4) ◽  
pp. 1643-1656 ◽  
Author(s):  
N. Swarnalingam ◽  
W. K. Hocking ◽  
P. S. Argall
Keyword(s):  
Cross Section ◽  
Great Level ◽  
Vhf Radar ◽  
Radar Echoes ◽  
Summer Echoes ◽  
Resolute Bay ◽  
Absolute Measurements ◽  
Coherent Radar ◽  
Backscatter Cross Section

Abstract. The Resolute Bay VHF radar, located in Nunavut, Canada (75.0° N, 95.0° W) and operating at 51.5 MHz, has been used to investigate Polar Mesosphere Summer Echoes (PMSE) since 1997. PMSE are a unique form of strong coherent radar echoes, and their understanding has been a challenge to the scientific community since their discovery more than three decades ago. While other high latitude radars have recorded strong levels of PMSE activities, the Resolute Bay radar has observed relatively lower levels of PMSE strengths. In order to derive absolute measurements of PMSE strength at this site, a technique is developed to determine the radar efficiency using cosmic (sky) noise variations along with the help of a calibrated noise source. VHF radars are only rarely calibrated, but determination of efficiency is even less common. Here we emphasize the importance of efficiency for determination of cross-section measurements. The significant advantage of this method is that it can be directly applied to any MST radar system anywhere in the world as long as the sky noise variations are known. The radar efficiencies for two on-site radars at Resolute Bay are determined. PMSE backscatter cross-section is estimated, and decade-long PMSE strength variations at this location are investigated. It was noticed that the median of the backscatter cross-section distribution remains relatively unchanged, but over the years a great level of variability occurs in the high power tail of the distribution.

scholarly journals A new approach to momentum flux determinations using SKiYMET meteor radars

2005 ◽  
Vol 23 (7) ◽  
pp. 2433-2439 ◽  
Author(s):  
W. K. Hocking
Keyword(s):  
New Mexico ◽  
Momentum Flux ◽  
Middle Atmosphere ◽  
Beam Forming ◽  
New Approach ◽  
Meteorology And Atmospheric Dynamics ◽  
Momentum Fluxes ◽  
Waves And Tides ◽  
Resolute Bay

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)

scholarly journals On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion

2002 ◽  
Vol 20 (11) ◽  
pp. 1857-1862 ◽  
Author(s):  
C. M. Hall
Keyword(s):  
Middle Atmosphere ◽  
Atmospheric Dynamics ◽  
Meteorology And Atmospheric Dynamics ◽  
Middle Atmosphere Dynamics ◽  
Radar Echoes ◽  
Meteor Trail ◽  
Meteor Trails

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)

scholarly journals Multi beam observations of cosmic radio noise using a VHF radar with beam forming by a Butler matrix

2011 ◽  
Vol 9 ◽  
pp. 349-357 ◽  
Author(s):  
T. Renkwitz ◽  
W. Singer ◽  
R. Latteck ◽  
M. Rapp
Keyword(s):  
Middle Atmosphere ◽  
Beam Forming ◽  
Cosmic Radio ◽  
Radio Noise ◽  
Spatiotemporal Resolution ◽  
Vhf Radar ◽  
Butler Matrix ◽  
The North ◽  
Noise Absorption ◽  
Cosmic Noise

Abstract. The Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn started to install a new MST radar on the North-Norwegian island Andøya (69.30° N, 16.04° E) in 2009. The new Middle Atmosphere Alomar Radar System (MAARSY) replaces the previous ALWIN radar which has been successfully operated for more than 10 years. The MAARSY radar provides increased temporal and spatial resolution combined with a flexible sequential point-to-point steering of the radar beam. To increase the spatiotemporal resolution of the observations a 16-port Butler matrix has been built and implemented to the radar. In conjunction with 64 Yagi antennas of the former ALWIN antenna array the Butler matrix simultaneously provides 16 individual beams. The beam forming capability of the Butler matrix arrangement has been verified observing the galactic cosmic radio noise of the supernova remnant Cassiopeia A. Furthermore, this multi beam configuration has been used in passive experiments to estimate the cosmic noise absorption at 53.5 MHz during events of enhanced solar and geomagnetic activity as indicators for enhanced ionization at altitudes below 90 km. These observations are well correlated with simultaneous observations of corresponding beams of the co-located imaging riometer AIRIS (69.14° N, 16.02° E) at 38.2 MHz. In addition, enhanced cosmic noise absorption goes along with enhanced electron densities at altitudes below about 90 km as observed with the co-located Saura MF radar using differential absorption and differential phase measurements.

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