Observed characteristics of atmospheric ducts over the South China Sea in autumn  

作　　者：成印河 周生启 王东晓 鲁远征 黄科 姚景龙 游小宝 

机构地区：[1]Guangdong Province Key Laboratory of Coastal Ocean Variation and Disaster Prediction, College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China [2]State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China [3]Beijing Institute of Applied Meteorology, Beijing 100029, China

出　　处：《Chinese Journal of Oceanology and Limnology》2016年第3期619-628,共10页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.41106011,41176027);the National Basic Research Program of China(973 Program)(No.2011CB403504)

摘　　要：The observed characteristics of lower atmospheric ducts over the South China Sea(SCS) were analyzed based on Global Position Systerm(GPS) radiosonde data collected four times daily during autumn open cruises from 2006 to 2012.Duct occurrence,thickness,and strength over the SCS were about 40%,150-m thick,and 8 M units,respectively,which were larger than during the summer monsoon period.Most ducts occurred at heights <1 500 m and these ducts easily trap electromagnetic wave clusters with wavelengths <2 m.Diurnal variation of the SCS ducts appeared evident.They occurred more often at midnight at higher altitudes(about 1 100 m),with a thickest layer of about 145 m and less frequently during the evening at lower altitudes(about 800 m),with a thinnest layer of about 125 m.Moreover,ducts during the daytime at a mean height of about 900 m,with the greatest strength of about 10 M units.Furthermore,all duct variables observed over the SCS in autumn decreased from north to south.These findings are useful not only in the design of radar and communication systems,but also for evaluating possible effects of anomalous propagation on meteorological radar and military applications.The observed characteristics of lower atmospheric ducts over the South China Sea （SCS） were analyzed based on Global Position Systerm （GPS） radiosonde data collected four times daily during autumn open cruises from 2006 to 2012. Duct occurrence, thickness, and strength over the SCS were about 40%, 150-m thick, and 8 M units, respectively, which were larger than during the summer monsoon period. Most ducts occurred at heights 〈1 500 m and these ducts easily trap electromagnetic wave clusters with wavelengths 〈2 m. Diurnal variation of the SCS ducts appeared evident. They occurred more often at midnight at higher altitudes （about 1 100 m）, with a thickest layer of about 145 m and less frequently during the evening at lower altitudes （about 800 m）, with a thinnest layer of about 125 m. Moreover, ducts during the daytime at a mean height of about 900 m, with the greatest strength of about 10 M units. Furthermore, all duct variables observed over the SCS in autumn decreased from north to south. These findings are useful not only in the design of radar and communication systems, but also for evaluating possible effects of anomalous propagation on meteorological radar and military applications.

关 键 词：GPS radiosonde atmospheric ducts AUTUMN statistical characteristics 

分 类 号：TN011[电子电信—物理电子学]