Wind and turbulence measurements by the Middle and Upper Atmosphere Radar (MUR): comparison of techniques

Abstract

Abstract. The structure-function-based method (referred to as UCAR-STARS), a technique for estimating mean horizontal winds, variances of three turbulent velocity components and horizontal momentum flux was applied to the Middle and Upper atmosphere Radar (MUR) operating in spaced antenna (SA) profiling mode. The method is discussed and compared with the Holloway and Doviak (HAD) correlationfunction-based technique. Mean horizontal winds are estimated with the STARS and HAD techniques; the Doppler Beam Swinging (DBS) method is used as a reference for evaluating the SA techniques. Reasonable agreement between SA and DBS techniques is found at heights from 5 km to approximately 11 km, where signal-to-noise ratio was rather high. The STARS and HAD produced variances of vertical turbulent velocity are found to be in fair agreement. They are affected by beam-broadening in a different way than the DBS-produced spectral width, and to a much lesser degree. Variances of horizontal turbulent velocity components and horizontal momentum flux are estimated with the STARS method, and strong anisotropy of turbulence is found. These characteristics cannot be estimated with correlation-function-based SA methods, which could make UCAR-STARS a useful alternative to traditional SA techniques.

Description and demonstration of the new Middle and Upper atmosphere Radar imaging system: 1‐D, 2‐D, and 3‐D imaging of troposphere and stratosphere

“…Apart from supporting radar imaging, the new multichannel digital receiver system makes it possible to utilize multiple signal‐processing algorithms on the same raw data. Thus, for example, SA‐configuration wind measurements using correlation‐function or structure‐function approaches [ Praskovsky et al , 2004] could be implemented and the information combined with radar imaging information about layer morphology. The potential for such combination of signal‐processing techniques makes the new MUR imaging system a valuable addition to the atmospheric science community.…”

Multi‐Receiver Augmentation to Advanced Indian MST Radar (AIR)—Implementation of Spaced Antenna Technique

“…The pattern life time provides the means for estimating turbulent velocities (Holdsworth et al., 2001). This has an advantage that the effects of beam broadening are negligible and thus no beam broadening‐correction is required (Holdsworth et al., 2001; Praskovsky et al., 2004; Rao & Kirkwood, 2005). Since auto‐correlation function is analogous to Doppler‐spectrum, the turbulent velocity is equal to spectral width (in ms −1 ) estimated with the DBS technique.…”

“…(1996) for obtaining horizontal winds by developing formulation relating advecting scattering medium to cross correlation/spectrum of echoes in spaced receivers. Different variants of the SA technique have been emerged over the years, like Cross/Auto Correlation Ratio (Holloway et al., 1997), lag of intersection of auto‐ and cross‐correlations (Cohn et al., 1997), slope at zero lag (Lataitis et al., 1995), Cross‐Correlation Ratio (Zhang et al., 2003) and structure‐function‐based analysis (Praskovsky et al., 2004). Several studies have shown that the performance of these different variants is similar to that of FCA (Chau & Balsley, 1998; Doviak et al., 2004; Kumar et al., 2014).…”

“…Several studies have shown that the performance of these different variants is similar to that of FCA (Chau & Balsley, 1998; Doviak et al., 2004; Kumar et al., 2014). The impact of distance between receiving antennas on wind estimation has been studied by combining arrays in a variety of ways (Aris et al., 2020; Holdsworth & Reid, 1997; Kumar et al., 2013; Praskovsky et al., 2004). Longer distance between receiving antennas decorrelates the signal, while the shorter distance causes underestimation of winds (triangle size effect).…”