# Turbulence: A Significant Role in Clear-Air Echoes of CINRAD/SA at Night
## 3 Instruments and Data  
### Instruments  
The data of clear-air echoes used in this study were collected by China's New Generation Weather Radar (CINRAD/SA radar) and three X-band dual-polarization (X-POL) radars with the same technical parameters [36]. CINRAD/SA was developed from the American WSR-88D (NEXRAD) through a joint agreement between the two countries [37]. The CINRAD/SA radar of Beijing is located in the Daxing district of Beijing and was fully upgraded with polarimetric capabilities in April 2021. The products of CINRAD/SA have a radial distance resolution of 250 m and an azimuthal resolution of 1 degree. The volume coverage pattern 21 (VCP21) scan mode was selected which sweeps 9 elevation angles of 0.5, 1.5, 2.4, 3.4, 4.3, 6.0, 9.9, 14.6, and 19.5 degrees in 6 min.  
The X-POL radars were built by the Beijing Meteorologic Service to improve radar usage in weather monitoring. The stations of the X-POL radars used in this study are in the Fangshan, Shunyi, and Tongzhou districts of Beijing (the BJXFS, BJXSY, and BJXTZ sites, respectively), located around the CINRAD/SA radar sites. The positions of the four radars and terrain are shown in Figure 1. The scan strategy for the X-Pol radars is the same as the CINRAD/SA radar. The detailed system characteristics of the CINRAD/SA radar and the X-POL radars are shown in Table 2.  
The operations of all these radars are under the supervision of the CMA. The CINRAD/SA and the X-POLs are also calibrated weekly and monthly according to the technical standard of the CMA, which includes the system internal calibration, the receiving link calibration, the rotary joint calibration, and others.  
Some meteorological parameters were used in this study. The profiles of the air temperature, the relative humidity, and the absolute humidity were collected using a microwave radiometer (RPG-HATPRO-G5, Meckenheim, Germany). The range resolution of the microwave radiometer was 50 m for heights below 1 km, 100 m for heights between 1 km and 2 km, and 250 m for heights from 2 km to 10 km, and the temporal resolution was 1 s. The wind vertical velocity and the wind shear were retrieved using a 3D Doppler wind  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Species** & **Average Weight** & **Average Length** & **Average Width** & **RCS of S-Band** & **RCS of X-Band** \\  & **(mg)** & **(mm)** & **(mm)** & **(dBsm)** & **(dBsm)** & **(dBsm)** \\ \hline \hline \begin{tabular}{c} Conogethes punctiferalis, \\ Hawaiian beet webworm, \\ Athetis lepione \\ \end{tabular} & 22.1 & 13.0 & 3.2 & \(-\)52.5 & \(-\)25.0 \\ \hline \
\begin{tabular}{c} Cotton bollworms, \\ Plusia agnata \\ \end{tabular} & 114.8 & 16.7 & 5.4 & \(-\)39.8 & \(-\)34.2 \\ \hline
\begin{tabular}{c} Armyworms, \\ Black cutworms, \\ Sprodoptera litura \\ \end{tabular} & 145.4 & 19.0 & 5.8 & \(-\)36.2 & \(-\)33.8 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Parameters of several insects and their RCSs at different wavelengths. The biometric data were provided by the Chinese Academy of Agricultural Sciences from captured insects in North China. The RCSs were simulated by FEKO simulation software using the prolate spheroid model of a spinal cord dielectric.  
lidar (Windcube 100 s, Leosphere, Saclay, France). The wind measurement products had a spatial resolution of 25 m with a temporal resolution of 20 s, and the products were not used when the carrier-to-noise ratio was less than \(-\)30 dB. A radar wind profiler (RWP) CFL-06, which was manufactured by the 23 rd Institute of the China Aerospace Science and Industry Corporation, was also used to detect and process the profiles of the horizontal wind speed and direction. The radar wind profiler operates in the L-band (1290 MHz) and provides data with a vertical resolution of 120 m for heights between 150 m and 2.9 km. The microwave radiometer, the wind lidar, and the wind profile radar were located several tens of meters from the S-band weather radar in the same observation field.