Zhongshan HF Radar Elevation Calibration Based on Ground Backscatter Echoes

Abstract

The super dual auroral radar network (SuperDARN) is an important tool in the remote sensing of ionospheric potential convection in middle and high latitudes, and also a major source of elevation data detection. A reliable elevation angle helps estimate the propagation paths of high-frequency radio signals between scattering spots and radars, which is crucial for determining high-frequency radar target geolocation. The SuperDARN radar uses interferometry to estimate the elevation of the returned signal. However, elevation data are still underutilized owing to the difficulties of phase difference calibration induced by the propagation time delay between two arrays. This paper statistically analyzes the distribution features of the group range-elevation angle and group range-virtual height before and after calibration using elevation data from the ground backscatter echoes of the Zhongshan SuperDARN radar, calculating the root mean square error (RMSE) of the virtual height; the results show that the RMSE after calibration is mostly reduced to within 54% of that before calibration. Furthermore, we validate the calibration factor based on the primary phase data. The data from 2013 to 2015 indicate that this technique can be efficiently used to estimate the daily calibration factor. Finally, we present the statistical distribution of the calibration factor, which provides technical support for the calibration of elevation data in the future.

Mesoscale Auroral Curls in Antarctica

“…This radar scans through 16 uniformly distributed beams with an azimuthal separation of ∼3.24°and produces a fan-shaped FOV map every minute (Chen et al, 2022;Greenwald et al, 1985Greenwald et al, , 1995. For each beam, the dwell time is 3 s and 75 range gates are sampled with a gate length of 45 km (Liu et al, 2011;Jiang et al, 2022). The ZHO radar has two channels performing different scanning patterns at the same time Liu et al, 2013).…”

“…Ionospheric flow data measured by the high frequency (HF) radar at ZHS (10.2–10.4 MHz) are used as well, which is a part of the Super Dual Auroral Radar Network (SuperDARN, Chisham et al., 2007) with the code “ZHO.” This radar scans through 16 uniformly distributed beams with an azimuthal separation of ∼3.24° and produces a fan‐shaped FOV map every minute (Chen et al., 2022; Greenwald et al., 1985, 1995). For each beam, the dwell time is 3 s and 75 range gates are sampled with a gate length of 45 km (Liu et al., 2011; Jiang et al., 2022). The ZHO radar has two channels performing different scanning patterns at the same time (Hu et al., 2013; Liu et al., 2013).…”

On the use of SuperDARN Ground Backscatter Measurements for Ionospheric Propagation Model Validation

“…We use the standard SuperDARN convention of zero-indexing when referring to beam numbers. GB measurements have found increasing utility over time, showing use for interferometer calibration (Jiang et al, 2022;Ponomarenko et al, 2015;Ponomarenko et al, 2018) and real time determination of ionospheric parameters including foF2 (Bland et al, 2014) and maximum useable frequency (MUF) (Hughes et al, 2002). Further applications include analysis of short-wave fadeout events by Chakraborty et al (2018) and derivation of ionospheric winds by Theurer and Bristow (2017).…”