Anomalous propagation conditions of electromagnetic wave observed over Bosten Lake, China in July and August, 2014

Abstract

Atmospheric duct is a common phenomenon over large bodies of water, and it can significantly affect the performance of many radio systems. In this paper, a two-month (in July and August, 2014) sounding experiment in ducting conditions over Bosten Lake was carried out at a littoral station (41.89 • N, 87.22 • E) with high resolution GPS radiosondes, and atmospheric ducts were observed for the first time in this area. During the two months, surface and surface-based ducts occurred frequently over the Lake. Strong diurnal variations in ducting characteristics were noticed in clear days. Ducting occurrence was found at its lowest in the early morning and at its highest (nearly 100%) in the afternoon. Duct strength was found increasing from early morning to forenoon, and reaching its maximum in the afternoon. But contrarily, duct altitude experienced a decrease in a clear day. Then the meteorological reasons for the variations were discussed in detail, turbulent bursting was a possible reason for the duct formation in the early morning and the prevailing lake-breeze front was the main reason in the afternoon. The propagation of electromagnetic wave in a ducting environment was also investigated. A raytracing framework based on Runge-Kutta method was proposed to assess the performance of radio systems, and the precise critical angle and grazing angle derived from the ray-tracing equations were provided. Finally, numerical investigations on the radar performance in the observed ducting environments have been carried out with high accuracy, which demonstrated that atmospheric ducts had made great impacts on the performance of radio systems. The range/height errors for radar measurement induced by refraction have also been presented, too, which shows that the height errors were very large for trapped rays when the total range was long enough.

First observations of elevated ducts associated with intermittent turbulence in the stable boundary layer over Bosten Lake, China

“…The data analyzed in the present study were collected during an investigation of the radio wave propagation conditions over Bosten Lake, a lake situated in the south of the Xinjiang Uygur Autonomous Region in China, in July 2014 and August 2014 [ Sun et al ., ]. A high‐resolution radiosonde (Changfeng GPS radiosonde; CF–06–A) attached to a tethered helium balloon was used to measure the vertical profiles of the air pressure, temperature, relative humidity, and balloon path up to a height of approximately 500 m. Then, modified refractivity profiles were calculated from the air pressure, temperature, and relative humidity profiles via equation .…”

“…The data analyzed in the present study were collected during an investigation of the radio wave propagation conditions over Bosten Lake, a lake situated in the south of the Xinjiang Uygur Autonomous Region in China, in July 2014 and August 2014 [Sun et al, 2016]. A high-resolution radiosonde (Changfeng GPS radiosonde;…”

Analysis of the accuracy of using ERA5 reanalysis data for diagnosis of evaporation ducts in the East China Sea

“…Using a refractometer to directly measure the atmospheric refractivity at different heights (Chai et al, 2022); b. Using a radiosonde and meteorological observation towers to measure meteorological parameters at different heights and indirectly calculating the vertical distribution of atmospheric refractivity (Liu et al, 1979;Karimian et al, 2012); c. Using an evaporation duct model (EDM) based on meteorological and hydrological parameters (Sun et al, 2016;Zhang et al, 2017).…”