Surveys in Geophysics

, Volume 22, Issue 5, pp 589–596

Derivation Of Refractive Index And Temperature Gradients From Optical Scintillometry To Correct Atmospherically Induced Errors For Highly Precise Geodetic Measurements

  • Alexandra I. Weiss
  • Maria Hennes
  • Mathias W. Rotach
Article

DOI: 10.1023/A:1015644923182

Cite this article as:
Weiss, A.I., Hennes, M. & Rotach, M.W. Surveys in Geophysics (2001) 22: 589. doi:10.1023/A:1015644923182

Abstract

Refraction effects of optical beams are generally caused by an inhomogeneous propagation medium and are a major source of systematic errors in the precise optical determination of angles and distances in the atmospheric surface layer. In this contribution a method for deriving vertical temperature and refractive index gradients from optical scintillation is presented. Knowledge of these gradients is required for the compensation of atmospherically induced errors for highly precise terrestrial geodetic measurements, like direct transfer and levelling. The advantage of the present optical method is, that temperature and refractive index gradients can be derived as line-averaged values over the propagation path, which is not possible by meteorological point measurements. Field observations have been carried out with a displaced-beam scintillometer over flat terrain and under different atmospheric conditions in order to verify this method. The experiments show, that this method allows to derive accurate correction values for precise terrestrial geodetic measurements.

Refractionrefractive indexscintillometrysensible heat flux

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Alexandra I. Weiss
    • 1
    • 2
  • Maria Hennes
    • 1
  • Mathias W. Rotach
    • 2
  1. 1.Institute of Geodesy and PhotogrammetrySwiss Federal Institute of Technology (ETH)ZurichSwitzerland
  2. 2.Institute for Atmospheric and Climate ScienceSwiss Federal Institute of Technology (ETH)ZurichSwitzerland