1280-MHz Active Array Radar Wind Profiler for Lower Atmosphere: System Description and Data Validation

Abstract

An L-band radar wind profiler was established at National Atmospheric Research Laboratory, Gadanki, India (13.5°N, 79.2°E), to provide continuous high-resolution wind measurements in the lower atmosphere. This system utilizes a fully active array and passive beam-forming network. It operates at 1280 MHz with peak output power of 1.2 kW. The active array comprises a 16 × 16 array of microstrip patch antenna elements fed by dedicated solid-state transceiver modules. A 2D modified Butler beam-forming network is employed to feed the active array. The combination of active array and passive beam-forming network results in enhanced signal-to-noise ratio and simple beam steering. This system also comprises a direct intermediate frequency (IF) digital receiver and pulse compression scheme, which result in more flexibility and enhanced height coverage. The scientific objectives of this profiler are to study the atmospheric boundary layer dynamics and precipitation. Observations made by this profiler have been validated using a collocated GPS sonde. This paper presents the detailed system description, including sample observations for clear-air and precipitation cases.

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

“…where u * is the friction velocity, u the surface horizontal velocity (8 m in our case), u h the wind shear at the top of ABL, g the acceleration due to gravity, θ vo the virtual potential temperature at the surface, d 1 is the depth of entrainment zone and A 2 and A 3 are empirical constants, A 2 = 0.005 and A 3 = 0.01 (Stull, 1976). For the estimation of advection (last term in Eq.…”

“…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.…”

Low-level mixing height detection in coastal locations with a scanning Doppler lidar

“…Emeis et al, 2008), but, in many environments, the daytime convective MLH exceeds the range of sodars. On the other hand, vertically pointing Doppler lidars and radar wind profilers are usually sensitive enough to reach the top of the atmospheric boundary layer and beyond but cannot see closer than an instrument-specific range, typically 100-200 m (Bianco et al, 2008;Pearson et al, 2009;Srinivasulu et al, 2012), which hampers the detection of low-level only mixing.…”

Advanced signal processing techniques for atmospheric applications using EMD

“…It can measure the complete Doppler spectrum of atmospheric targets with a time resolution on the order of 1 min and a range resolution of about 100m. These data may be used to estimate the Moments, Noise Levels and UVW Computation [2]. LAWP radar can be used to distinguish the clear-air scattering from the precipitation scattering arising from cloud and rain drops.…”

“…Step (4): Regarding ( ) 1 r t as new data and repeating steps (1), (2) and (3) until finding all the IMFs. The sifting procedure is terminated until the n th residue ( ) r t n becomes less than a predetermined small number or the residue becomes monotonic.…”