A new model for the structure function of integrated water vapor in turbulence

Turbulent fluctuation of integrated water vapor in the troposphere is one o f the major noise sources in radio interferometry. Processed integrated wat er Vapor estimates from microwave radiometers colocated with interferometer s have been used to set bounds on this uncertainty. The bound has been in t he form of a calculated structure function, which is a measure of temporal or spatial decorrelation of fluctuations. In this paper a new model is pres ented for the estimation of the structure function in the absence of radiom eter measurements. Using this model, the structure function can be estimate d using measurements or estimates of a limited number of meteorological par ameters. These parameters include boundary layer depth, surface heat and hu midity fluxes, entrainment humidity flux, average virtual potential tempera ture in the boundary layer, and geostrophic wind speed. These parameters ca n be found or estimated from radiosonde and surface eddy correlation system data. The model is based on a framework of turbulence meteorology and prov ides excellent agreement when compared with state-of-the-art atmospheric tu rbulence simulations. Results of preliminary comparisons with ground truth show some excellent agreement, as well as some problems. The performance of the new model exceeds that of one current model.