Generation of Slant Tropospheric Delay Time Series Based on Turbulence Theory

GNSS phase observations are well suited to study atmospheric refraction effects and to contribute to weather prediction. Current research activities focus on real time determination of slant tropospheric wet delays in order to determine the water vapor content. The long periodic variations of these delays are mainly caused by the steady state component of the refractive index field. In contrast, short periodic variations of the slant delays are induced by refractivity fluctuations along the signal's path from the transmitter to the receiver. Focusing on higher temporal resolution of water vapor variations, this second component will be of special interest. Based on turbulence theory, Schön and Brunner (J Geodes 82(1): 47-57) developed a formulation of the variances and covariances of GNSS phase observations induced by refractivity fluctuations in the troposphere. In this paper, we will use this model to investigate the generation of slant delay time series based on a spectral decomposition of the simulated turbulence theory-based variance-covariance matrices. Using an exemplary GPS configuration, the impact of the model parameters (as e.g. the refractivity structure constant, the outer scale length, the effective tropospheric height, and the wind direction and magnitude) on the covariance matrix and the generated time series is analysed.