大气效应尤其是大气水汽的影响是InSAR干涉测量中主要的误差源和限制因素之一,因此高精度的InSAR应用迫切需要及时掌握大气水汽含量及其时空变化。本文深入分析了利用MODIS的水汽反演结果进行InSAR干涉测量大气校正的可行性,对MODIS近红外水汽反演结果与地基GPS水汽探测结果进行了比较和分析。同时根据GPS解算结果,利用实例讨论了基于地面气象参数的水汽延迟模拟的效果。

Atmospheric water vapor is highly variable in both space and time,and the accuracy of Interferometric synthetic aperture radar(InSAR) is limited by the effect of the atmosphere,especially the atmospheric water vapor on repeat-pass InSAR measurements.In order to assess the competence of the MODIS(the Moderate-Resolution Imaging Spectroradiometer) near-infrared water vapor retrieval and gound meteorological model estimation for correcting atmospheric effects on InSAR measurements,coincident observations obtained from Global Positioning System(GPS) measurements at five sites in Fangshan Beijng over a month period(April 2004) are used for time series and spatial comparisons.Comparisons of PWV between MODIS and GPS show that their correlation coefficients are high although MODIS appeared to overestimate PWV against GPS;The wet components of tropospheric delay estimated using two empirical models from the ground meteorological data obtained at the GPS sites show low correlation coefficients with the results derived from GPS.