HCOPAR

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Coordinates: 19 ° 30 '0 "  N , 109 ° 6' 0 '  O The Hainan Coherent Scatter Phased Array Radar ( Chinese  海南相干散射雷達  / 海南相干散射雷达 , Pinyin Hǎinán Xianggan Sǎnshè LEIDA short HCOPAR ) is a Chinese over-the-horizon radar - Transmitting and receiving system for high-power emissions in the ultra-short wave range . The emissions use the E and F layers of the ionosphere as reflectivelayers. Thefacility, operatedby the Hainan Sounding Department of the Chinese Academy of Sciences , is located a little northeast of the Hongling community of Yaxing municipality on the island of Hainan .

technology

Working principle

The maximum transmission power of the system is 54 kilowatts, the transmission frequency is 47.5 MHz. The antenna array consists of 18 by 4 linearly polarized five-element Yagi antennas aligned along an east-west axis and oriented to the north . The array covers an area of ​​2000 m². Thanks to the antenna arrangement, seven radiation directions can be switched in azimuth with an angular step of 7.5 °, from 22.5 ° west of true north to 22.5 ° east of true north, with a cycle lasting 120 seconds. The antennas are inclined vertically by 28.2 ° from the zenith , which means that, unlike in the illustration opposite, the radar beam hits the Hainan earth's magnetic field at an angle of 90 ° at the level of the E and F layers of the ionosphere. The radar signal is reflected directly; the antennas function as both transmitting and receiving antennas. In order to enable a more precise observation of the temporal course of the changes in the ionosphere, the radar can also be used with just one beam, which then points directly north. In such a case, a send-receive cycle only takes 20 seconds.

task

The system is used to research the high atmosphere , it is an important element of the Chinese Meridian Space Weather Monitoring Project (子午 工程 or Meridian Project). It is used to investigate so-called field aligned irregularities in the E and F layers of the ionosphere, changes in the plasma density usually lasting several hours, during which the electrons align themselves with the earth's magnetic field . Usually this phenomenon occurs in lower latitudes during the night. However, on July 22, 2013 and May 23, 2016 such irregularities - in the upper F 2 layer - could be observed around noon. In parallel to the observations with the HCOPAR, two ion probes are used to record ionograms on a regular basis and to obtain information about the "background ionosphere" in which the FAIs occur. Both devices are dig probes from the Center for Atmospheric Research at the University of Massachusetts Lowell . One is installed at the headquarters of the Hainan sounding research department near Fuke village, about 5 km northeast of the radar system, the other in the Shaoyang branch of the Guangzhou meridian station .

Individual evidence

  1. ↑ 崔 啸: 基于 天线 阵列 的 雷达 系统 设计 与 应用 研究. In: gb.oversea.cnki.net. Retrieved May 20, 2020 (Chinese).
  2. ↑ 子午 工程 无线电 设备 - 海南 VHF 雷达 天线 阵. In: lssf.cas.cn. January 28, 2016, accessed May 20, 2020 (Chinese).
  3. ↑ HCOPAR at researchgate.com
  4. ↑ 王霄: 空间 环境 之 无线电 探测. In: cauc.edu.cn. October 10, 2015, accessed May 20, 2020 (Chinese).
  5. ↑ Chen Gang, Jin Han, Yan Jingye, Cui Xiao, Zhang Shaodong: Hainan Coherent Scatter Phased Array Radar (HCOPAR): System Design and Ionospheric Irregularity Observations . In: IEEE Transactions on Geoscience and Remote Sensing . tape 55 , no. 8 , August 2017, ISSN  0196-2892 , p. 4757-4765 , doi : 10.1109 / TGRS.2017.2699280 ( ieee.org [accessed April 7, 2019]).
  6. ↑ a b Chen Gang et al .: Low ‐ latitude daytime F region irregularities observed in two geomagnetically quiet days by the Hainan coherent scatter phased array radar (HCOPAR). In: agupubs.onlinelibrary.wiley.com. February 18, 2017, accessed May 20, 2020 .
  7. ↑ 子午 工程 ： 空间 科学 国 之 重 器. In: sciping.com. September 9, 2019, accessed May 20, 2020 (Chinese).
  8. ↑ Global Map of GIRO Digisondes. In: digisonde.com. Retrieved May 21, 2020 (English).