title: GPT2: Empirical slant delay model for radio space geodetic techniques.
abstract: Up to now, state-of-the-art empirical slant delay modeling for processing observations from radio space geodetic techniques has been provided by a combination of two empirical models. These are GPT (Global Pressure and Temperature) and GMF (Global Mapping Function), both operating on the basis of long-term averages of surface values from numerical weather models. Weaknesses in GPT/GMF, specifically their limited spatial and temporal variability, are largely eradicated by a new, combined model GPT2, which provides pressure, temperature, lapse rate, water vapor pressure, and mapping function coefficients at any site, resting upon a global 5° grid of mean values, annual, and semi-annual variations in all parameters. Built on ERA-Interim data, GPT2 brings forth improved empirical slant delays for geophysical studies. Compared to GPT/GMF, GPT2 yields a 40% reduction of annual and semi-annual amplitude differences in station heights with respect to a solution based on instantaneous local pressure values and the Vienna mapping functions 1, as shown with a series of global VLBI (Very Long Baseline Interferometry) solutions.
authors.affiliation: Department of Geodesy and Geoinformation (Research Group Advanced Geodesy), Vienna University of Technology Vienna, Austria ; Institute of Geodesy and Photogrammetry (Geosensors and Engineering Geodesy) ETH Zurich, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Lagler
authors.affiliation: Department of Geodesy and Geoinformation (Research Group Advanced Geodesy), Vienna University of Technology Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Schindelegger
authors.affiliation: Department of Geodesy and Geoinformation (Research Group Advanced Geodesy), Vienna University of Technology Vienna, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Böhm
authors.affiliation: Department of Geodesy and Geoinformation (Research Group Advanced Geodesy), Vienna University of Technology Vienna, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Krásná
authors.affiliation: Department of Geodesy and Geoinformation (Research Group Advanced Geodesy), Vienna University of Technology Vienna, Austria ; Section 1.1, GPS/GALILEO Earth Observation, Deutsches GeoForschungsZentrum Potsdam, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Nilsson