基于GPS探空数据的南海海域大气波导特征分析

Statistical analysis of atmospheric ducts in the South China Sea based on GPS sounding

为了更精确地掌握南海海域大气波导的统计特征,详细分析了大气折射率关于温度、湿度和压强的敏感性,并在此基础上利用2006—2010年南海航次GPS探空资料对该海域表面波导和悬空波导的发生概率和波导特征参数进行了统计分析.结果表明:表面波导年平均发生概率基本在20%以下,波导顶平均高度约为167 m,陷获层厚度一般不超过30 m,强度介于4.5~9.6 M,年度平均值为7.5 M;悬空波导年平均发生概率接近50%,波导顶高度一般介于1100~1300 m,陷获层厚度比表面波导略高,平均厚度为32.8 m,强度平均值与表面波导相当,但跨度比表面波导要小得多.统计分析结果可为南海区域舰载无线电系统的运行保障提供参考.

In order to master the statistical characteristics of atmospheric duct in the South China Sea more accurately,the sensitivity of atmospheric refractive index of temperature,pressure and humidity are analyzed in detail.Based on the cruising GPS sounding data in the South China Sea from the year of 2006 to 2010,statistical analysis of the occurrence probability of surface-based duct and elevated duct,and their characteristic parameters are computed and analyzed.The results show that the average occurrence probability of surface-based duct is relatively low,generally less than 20%.The average height of the top of surface-based duct is about 167 m,and the thickness of the trapped layer is below 30 m.The strength is between 4.5 M-units and 9.6 M-units,and the annual average is 7.5 M-units.While the average occurrence probability of elevated duct is near to 50%,and the height of the top of elevated duct is generally between 1100 m and 1300 m.The thickness of the trapped layer is at an average value of 32.8 m,which is slightly higher than that of the surface-based duct.The average strength of elevated duct is close to that of the surface-based duct,but its span is much smaller.These results can provide reference for the operation of ship-borne radio system in the South China Sea.