海洋蒸发波导自然现象对近海面电磁波的传播有重要影响,获取大面积海域蒸发波导的长时间统计分布规律,对于海上雷达、通信、制导等电磁系统的设计与应用,具有重要意义.针对现有单点局部观测方法的缺点,建立了基于美国环境预报中心再分析数据的大面积海域蒸发波导统计特性计算方法,利用太平洋气象浮标数据、北部湾海岛气象观测数据对分析方法的正确性进行了验证.利用该分析方法和最近18年的美国环境预报中心再分析数据,重点研究了西太平洋蒸发波导的统计规律,获得了蒸发波导高度在不同海域、不同月份的分布特性,建立了空间分辨率约为1.875°×1.9°的蒸发波导特性数据库,与国外现有的10°×10°数据库相比,不仅分辨率提高约28倍,而且精度更高.
The evaporation duct is a natural microwave trapping phenomenon over water surfaces,which has a strong impact on near-surface electromagnetic propagation.For radar and communication system designs and operations,it is of great significance to obtain the long-term mean features of evaporation duct in a large-scale sea.In order to overcome the shortcomings of single-point measurement at local sea,a method for calculating the statistical features of the evaporation duct in a large scale-sea based on the NCEP (National Centers for Environmental Prediction) reanalysis data was presented. This method was confirmed by using the weather buoy data at the Pacific Ocean and the measurement data on the Weizhou Island in the South Sea of China. With NCEP reanalysis data of 18 years, the spatio-temporal features of evaporation duct in the West Pacific Ocean were studied. The distribution features of the evaporation duct height for different seas and months were obtained. The evaporation duct database was established with spatial resolution of about 1. 875°× 1.9°, which is 28 times higher than the existing 10°× 10°database.