Simplified Active Array L-Band Radar for Atmospheric Wind Profiling: Initial Results

Srinivasulu, P.; Yasodha, P.; Jayaraman, A.; Reddy, Sreedhar; Satyanarayana, S.

doi:10.1175/jtech-d-11-00011.1

Cited by 22 publications

(9 citation statements)

References 30 publications

(31 reference statements)

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“…Whereas, the larger profiler has a bigger antenna array of 2.8 m × 2.8 m with 16 × 16 elements and high-transmitting power of 1.2 kW (hereafter referred to as WPR 16×16 ). Complete description of these systems and their capabilities can be found in Srinivasulu et al (2011Srinivasulu et al ( , 2012. The WPR 8×8 was operated at NARL during May-September 2010, while the bigger WPR 16×16 has been in operation from October 2010.…”

Section: Data and Site Descriptionmentioning

confidence: 99%

A comprehensive investigation on afternoon transition of the atmospheric boundary layer over a tropical rural site

Sandeep

Rao

2015

Atmos. Chem. Phys.

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Abstract. The transitory nature of the atmospheric boundary layer (ABL) a few hours before and after the time of sunset has been studied comprehensively over a tropical station, Gadanki (13.45 • N, 79.18 • E), using a suite of in situ and remote sensing devices. This study addresses the following fundamental and important issues related to the afternoon transition (AT): which state variable first identifies the AT? Which variable best identifies the AT? Does the start time of the AT vary with season and height? If so, which physical mechanism is responsible for the observed height variation in the start time of the transition?At the surface, the transition is first seen in temperature (T ) and wind variance (σ 2 WS ), ∼ 100 min prior to the time of local sunset, then in the vertical temperature gradient and finally in water vapor mixing ratio variations. Aloft, both signal-to-noise ratio (SNR) and spectral width (σ ) show the AT nearly at the same time. The T at the surface and SNR aloft are found to be the best indicators of transition. Their distributions for the start time of the AT with reference to time of sunset are narrow and consistent in both total and seasonal plots. The start time of the transition shows some seasonal variation, with delayed transitions occurring mostly in the rainy and humid season of the northeast monsoon. Interestingly, in contrast to the general perception, the signature of the transition is first seen in the profiler data, then in the sodar data, and finally in the surface data. This suggests that the transition follows a top-to-bottom evolution. It indicates that other processes, like entrainment, could also play a role in altering the structure of the ABL during the AT, when the sensible heat flux decreases progressively. These mechanisms are quantified using a unique high-resolution data set to understand their variation in light of the intriguing height dependency of the start time of the AT.

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Section: Data and Site Descriptionmentioning

confidence: 99%

A comprehensive investigation on afternoon transition of the atmospheric boundary layer over a tropical rural site

Sandeep

Rao

2015

Atmos. Chem. Phys.

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“…Wind profilers are used to obtain estimates of horizontal and vertical wind velocities using acoustic and radar remote sensing techniques. Remote sensing of winds and turbulence in the lower atmosphere by the Doppler beam swinging technique is widely incorporated by wind profiling radars .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, high linearity is also required for a LNA along with low noise figure and high gain. Power consumption will not be considered in the design of LNA in a wind profiler, as the T/R modules will handle kilowatts of power and wind profilers will radiate a peak power of well above 1.5 kW . The design of a LNA is dependent on the application for which it is used and frequency of operation.…”

Section: Introductionmentioning

confidence: 99%

Design of narrow band UHF low noise amplifier for wind profilers

Murthy

Rao

2015

Microw. Opt. Technol. Lett.

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The design of UHF low noise amplifier (LNA) aiming for wind profiling radar application is presented in this article. The receiver sensitivity in detecting long distance atmospheric signals of a wind profiling radar depends on the noise performance of the LNA. Modified source degenerated inductance methodology along with the high pass matching circuit is used for the improvement of noise figure, input and output return losses. It is shown that the designed LNA circuit is capable of achieving low noise performance with narrow band tuning at 1.3 GHz. The LNA is designed in a pHEMT technology and fabricated on a RT/duroid substrate. The measured results of the designed LNA show a maximum gain of 18.78 dB with an associated noise figure of 0.45 dB. The input and output return losses (S11 and S22) are 10.7 and 14 dB and we have achieved a high third order input intercept point (IIP3) of 52 dBm. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:600–603, 2015

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“…The L-band Lower Atmospheric Wind Profiler (LAWP) is used for conducting research in the lower atmosphere [1]. National Atmospheric Research Laboratory (NARL) at Gadanki (13.47°N,79.18°E) near Tirupati, India has been operating this 1280 MHz, atmospheric radar for studying structure and dynamics of the lower atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Advanced signal processing techniques for atmospheric applications using EMD

Murthy

Reddy

2015

2015 International Conference on Microwave, Optical and Communication Engineering (ICMOCE)

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The main objective of the Lower Atmospheric Wind Profiler (LAWP) is used to provide continuous high resolution wind measurements in all weather conditions. Signal processing of this atmospheric radar is necessary to measure the height profile of wind vector by detecting the Doppler shift of echoes and signal to noise ratio (SNR). The L-band wind profiler is used for conducting research in the lower atmosphere. These radars achieve better range resolution with maximum average power (height coverage). The signals, which are processed in the present work has been obtained from the LAWP at National Atmospheric Research Laboratory (NARL), Gadanki, India. SNR computation is an important parameter in signal processing. This paper discusses improvement of SNR using Empirical Mode Decomposition (EMD) for LAWP signals. SNR for this data is computed de-noised signals and EMD de-noised signals are compared with the Wavelets de-noised signals. Results shows that there is an improvement in SNR after denoising using EMD technique for LAWP signals.

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Simplified Active Array L-Band Radar for Atmospheric Wind Profiling: Initial Results

Cited by 22 publications

References 30 publications

A comprehensive investigation on afternoon transition of the atmospheric boundary layer over a tropical rural site

A comprehensive investigation on afternoon transition of the atmospheric boundary layer over a tropical rural site

Design of narrow band UHF low noise amplifier for wind profilers

Advanced signal processing techniques for atmospheric applications using EMD

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