2010 Volume 21 Issue 4 Pages 209-219
Atmospheric delay of radio wave propagation is a major source of error for crustal deformation measurements using InSAR(Interferometric Synthetic Aperture Radar).Atmospheric delay is caused by topography and horizontal inhomogeneity of water vapor distribution.When accurate weather information is not enough,it is difficult to estimate effects of horizontal water vapor inhomogeneity.This paper discusses the analog weather map method to estimate water vapor effects on the satellite JERS-1 SAR interferometry in the observation period with no accurate weather data.A case study was undertaken of a JERS-1 interferometric pair on Nobi plain.Using GPV-MSM(Grid Point Value of Meso-Scale Model),water vapor distribution in the satellite observation days is recovered,and the atmospheric delay generated by water vapor inhomogeneity was quantitatively evaluated.The results show that the vertical change of differential refractivity between the two observation days does not a simple linear relationship. Maximum atmospheric delay difference due to horizontal water vapor inhomogeneity is about 38mm in the study area.Spatial distribution pattern of the atmospheric delay estimated by the GPV-MSM data is found to be similar to the phase pattern of differential interferometry.
