Improved Mapping of Tropospheric Delays

Abstract The authors compare several methods to map the a priori tropospheric delay of global positioning system (GPS) signals from the zenith direction to lower elevations. This is commonly achieved with so-called mapping functions. Dry mapping functions are applied to the hydrostatic delay; wet mapping functions are used to map the zenith wet delay to lower elevation angles. The authors compared the following mapping techniques against raytraced delays computed for radiosonde profiles under the assumption of spherical symmetry: (a) the Niell mapping function; (b) mapping through the COSPAR International Reference Atmosphere with added water vapor climatology; (c) the same as b with added use of surface meteorological temperature, pressure, and humidity; and (d) use of the numerical reanalysis model of the National Centers for Environmental Prediction–National Center for Atmospheric Research. Based on comparisons with all available global radiosondes (∼1000 per day), for every fifth day of 1997 (73 days)...

[1]  I. Meroz,et al.  Fundamentals of general meteorology : physics of the atmosphere , 1967 .

[2]  G. Ruffini,et al.  4D tropospheric tomography using GPS slant wet delays , 2000 .

[3]  I. Shapiro,et al.  Geodesy by radio interferometry: Effects of atmospheric modeling errors on estimates of baseline length , 1985 .

[4]  T. Herring,et al.  GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System , 1992 .

[5]  Anthony R. Lowry,et al.  Vertical profiling of atmospheric refractivity from ground‐based GPS , 2002 .

[6]  G. Veis.  The Use of Artificial Satellites for Geodesy , 1963 .

[7]  G. D. Thayer,et al.  An improved equation for the radio refractive index of air , 1974 .

[8]  X. Zou,et al.  Analysis and validation of GPS/MET data in the neutral atmosphere , 1997 .

[9]  Cleve Moler,et al.  Mathematical Handbook for Scientists and Engineers , 1961 .

[10]  Thomas A. Herring,et al.  Effects of atmospheric azimuthal asymmetry on the analysis of space geodetic data , 1997 .

[11]  A. Niell.  Global mapping functions for the atmosphere delay at radio wavelengths , 1996 .

[12]  Christian Rocken,et al.  Sensing integrated water vapor along GPS ray paths , 1997 .

[13]  S. Sokolovskiy,et al.  Use of GPS for estimation of bending angles of radio waves at low elevations , 2001 .

[14]  J. W. King,et al.  Radio Ray Propagation in the Ionosphere , 1964 .

[15]  Y. Kravtsov,et al.  Geometrical optics of inhomogeneous media , 2019, Geometrical Optics of Weakly Anisotropic Media.

[16]  D. S. MacMillan,et al.  Evaluation of very long baseline interferometry atmospheric modeling improvements , 1994 .

[17]  Soroosh Sorooshian,et al.  SuomiNet: A Real-Time National GPS Network for Atmospheric Research and Education. , 2000 .

[18]  A. MacDonald.  On the use of slant observations from GPS to diagnose three dimensional water vapor using 3DVAR , 2000 .

[19]  J. Owens,et al.  Optical refractive index of air: dependence on pressure, temperature and composition. , 1967, Applied optics.

[20]  Christian Rocken,et al.  Near real‐time GPS sensing of atmospheric water vapor , 1997 .

[21]  R. Reynolds,et al.  The NCEP/NCAR 40-Year Reanalysis Project , 1996, Renewable Energy.

[22]  Christian Rocken,et al.  Validation of line‐of‐sight water vapor measurements with GPS , 2001 .