InSAR生成DEM中WRF大气校正
Atmospheric correction of spaceborne repeat-pass InSAR DEM generation based on WRF
- 2016年20卷第5期 页码:1151-1160
纸质出版日期: 2016
DOI: 10.11834/jrs.20166174
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纸质出版日期: 2016 ,
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[1]曾琪明,章晓洁,焦健.InSAR生成DEM中WRF大气校正[J].遥感学报,2016,20(05):1151-1160.
ZENG Qiming, ZHANG Xiaojie, JIAO Jian. Atmospheric correction of spaceborne repeat-pass InSAR DEM generation based on WRF[J]. Journal of Remote Sensing, 2016,20(5):1151-1160.
利用星载重复轨道合成孔径雷达干涉测量InSAR技术获取数字高程模型(DEM)
无法避免大气延迟效应的影响。InSAR大气校正的方法很多
但在DEM获取方面的大气校正研究却非常少见。本文研究星载重轨InSAR生产DEM时利用大气数值模式WRF(Weather Research and Forecasting model)得到的水汽结果进行大气校正的问题
重点讨论大气校正的策略
包括WRF模式设置和大气校正时机的选择
简要介绍了基于WRF运算结果的大气校正方法。利用Terra SAR-X数据进行实验
检验了所提出方法的有效性
证明了在干涉相位解缠前进行大气校正
比在相位解缠后进行的效果更好。将所提出方法应用于多基线、多波段InSAR干涉结果融合中
实验结果表明大气校正能够有效降低误差
对于相干性较高的地区效果更好。
Atmospheric delay effect is unavoidable and sometimes serious when using spaceborne repeat-pass synthetic aperture radar interferometry(InSAR) to generate Digital Elevation Models(DEMs). InSAR atmospheric correction methods come in various types. However
they are rarely used in InSAR DEM generation. The method based on atmospheric numerical models offersunique advantages.It can estimate atmospheric water vapor field at the SAR data acquisition time
and it is not affected by clouds. Therefore
this work studies the atmospheric correction strategy and method during the process of InSAR DEM generation based on the atmospheric numerical model called the Weather Research and Forecasting(WFR) model to improve the accuracy of the generated InSAR DEM.First
atmospheric correction strategies are discussed. These strategies include the proper settings of WRF Preprocessing System(WPS)to make the temporal and spatial scales of WRF results match those of SAR data
as well as the selection of a proper atmospheric correction timing to improve the accuracy of InSAR DEMs. One of the key issues of InSAR is phase unwrapping
and atmospheric correction removes the residual atmospheric phase from the interferometric phase of SAR data. Thus
there are two possible atmospheric correction timings: before phase unwrapping and after phase unwrapping. Atmospheric correction before phase unwrapping is theoretically helpful for phase unwrapping because the contribution of the atmosphere is removed. Atmospheric correction after phase unwrapping is commonly used in the field of Differential InSAR(D-InSAR)
and its efficiency has been validated. The topographic phase in the process of D-InSAR is removed before phase unwrapping
which makes phase unwrapping easier than that in the process of InSAR DEM generation. A method of atmospheric correction based on WRF results is then introduced. The direct output results of WRF are not atmospheric water vapor field
which is needed to calculate the residual atmospheric phase. Thus
a method for transforming the direct output results of WRF to integrated water vapor(IWV) andthen transforming the IWV to the residual atmospheric phase is introduced. The original coordinates of the WRF results are transformed to the coordinates of SAR data. A workflow of atmospheric correction during the process of InSAR DEM generation is proposed. Experiments are carried outwith Terra SAR-X data to validate the efficiency of the proposed methods. The accuracies of the generated InSAR DEMs with residual atmospheric phase corrected at each possible timing are compared. The compared qualitative and quantitative results prove that the atmospheric corrections work at both timings and that the atmospheric correction before phase unwrapping performs well. However
the atmospheric correction before phase unwrapping may not always work or may worsen the accuracy of the DEM resultin regions where interferometric qualities are poor. The proposed methods are then applied to the fusion of multi-baseline and multi-frequency InSAR results
with the experimental resultsalso proving the efficiency of the methods and the good performance of atmospheric correctionin regions of good interferometric quality.
大气校正DEMWRFInSAR多基线多波段
atmospheric correctionDEMWRFInSARmulti-baseline multi-frequency
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