HR: 14:55h
AN: G42B-06    [PDF]
TI: Assessing the Accuracy of Slant Path Measurements Using a High Resolution Numerical Weather Model
AU: * Braun, J
EM: braunj@ucar.edu
AF: University Corporation for Atmospheric Research\\ COSMIC Program, P.O. Box 3000, Boulder, CO 80307 United States
AU: Ha, S
EM: syha@ucar.edu
AF: University Corporation for Atmospheric Research\\ COSMIC Program, P.O. Box 3000, Boulder, CO 80307 United States
AU: Rocken, C
EM: rocken@ucar.edu
AF: University Corporation for Atmospheric Research\\ COSMIC Program, P.O. Box 3000, Boulder, CO 80307 United States
AU: Kuo, B
EM: kuo@ucar.edu
AF: University Corporation for Atmospheric Research\\ COSMIC Program, P.O. Box 3000, Boulder, CO 80307 United States
AB: The ability to derive the delay induced by the neutral atmosphere along individual ray paths between a GNSS satellite and a receiving station can provide more detailed atmospheric information than zenith delay measurements. These line-of-sight integrals are often called slant path delays. Comparisons of slant water vapor measured by a pointing microwave radiometer and a collocated GPS receiver have shown better agreement than comparisons of the more commonly estimated zenith wet delay or precipitable water vapor. We have investigated the errors in slant path measurements using simulated observations from a high-resolution numerical weather model. This simulation described the passage of a squall line over a large portion of the United States Southern Great Plains region and had a high degree of both hydrostatic and wet delay variability. This simulation provided the opportunity to study the effect of realistic systematic and random errors on the slant delay sensing technique. We found that the largest errors in the estimated slant path values are systematic in nature and affect all neutral atmosphere delay estimates in the same way. This means that systematic errors introduce errors in the zenith delay estimates that are then mapped into the slant delay estimates. In contrast, the error in determining the anisotropic delay between a GNSS satellite and a receiving station is small. In summary, the retrieved slant path values can have periods where systematic errors result in significant errors of the estimated zenith delay, while the anisotropic variability of the atmosphere can still be recovered with high precision.
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2003 Fall Meeting