基于高斯函数的ZTD模型系数时空特性分析

Analysis of Spatiotemporal Characteristics of ZTD Model Coefficients Based on Gaussian Function

广西地区地形起伏较大、气候复杂,已有的低时空分辨率对流层天顶延迟(Zenith Total Delay,ZTD)垂直剖面模型难以满足该地区的需求,以高斯函数对高时空分辨率的ERA5再分析资料计算的分层ZTD进行拟合,分析2016—2017年拟合系数的时空分布特性。结果表明,基于高斯函数的ZTD模型系数b与系数c均具有显著的年周期、半年周期、日周期、半日周期变化;系数b与系数c的年均值、年周期振幅、半年周期振幅、日周期振幅和半日周期振幅均具有显著的区域性;系数b与经度的相关系数为-0.824,与纬度的相关系数为0.969;系数c与经度的相关系数为0.822,与纬度的相关系数为-0.968,二者与经纬度均具有较高的相关性。

As the terrain fluctuations vary from place to place and the climate is complex in Guangxi,the existing vertical profile model of tropospheric Zenith Total Delay(ZTD)with low temporal and spatial resolution cannot meet the needs of the region.The layered ZTD calculated using the ERA5 analysis data is fitted with Gaussian function.The spatiotemporal distribution characteristics of the fitting coefficients from 2016 to 2017 are analyzed.The results show that the coefficient b and c of the ZTD model based on the Gaussian function have significant annual,semi-annual,daily and semi-daily cycle changes.The annual mean value,annual cycle amplitude,semi-annual cycle amplitude,daily cycle amplitude and semi-daily cycle amplitude of coefficient b and c have significant regionality.The correlation coefficient between coefficient b and longitude is-0.824,and the correlation coefficient with latitude is 0.969.The correlation coefficient between coefficient c and longitude is 0.822,and the correlation coefficient with latitude is-0.968.Both the coefficients have high correlation with longitude and latitude.