Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization

The delay caused by the troposphere is one of the major sources of errors limiting the accuracy of InSAR measurements. The tropospheric correction of InSAR measurements is important. The Weather Research and Forecasting (WRF) Model is a state-of-the-art mesoscale numerical weather prediction system...

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Main Authors: Qinghua Liu, Qiming Zeng, Zhiliang Zhang
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/15/1/273
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author Qinghua Liu
Qiming Zeng
Zhiliang Zhang
author_facet Qinghua Liu
Qiming Zeng
Zhiliang Zhang
author_sort Qinghua Liu
collection DOAJ
description The delay caused by the troposphere is one of the major sources of errors limiting the accuracy of InSAR measurements. The tropospheric correction of InSAR measurements is important. The Weather Research and Forecasting (WRF) Model is a state-of-the-art mesoscale numerical weather prediction system designed for atmospheric research applications. It can be applied to InSAR tropospheric correction. Its parameters can be altered according to the requirements of the given application. WRF is usually initialized based on 3 h- or 6 h temporal resolution data in InSAR tropospheric correction studies, a lower temporal resolution compared to ERA5 data. A lower time resolution means a longer integration time for WRF to simulate from the initial time to the target time. Initialization with a higher resolution can shorten the integration time of the simulation theoretically and improve its accuracy. However, an evaluation of the effectiveness of ERA5_WRF for InSAR tropospheric correction is lacking. To evaluate the efficiency of WRF tropospheric correction, we used Reanalysis v5 (ERA5) from the European Centre for Medium-Range Weather Forecasts (ECMWF) for initialization to drive the WRF (ERA5_WRF) for efficient applications in InSAR. Three methods based on global atmospheric models—FNL_WRF (tropospheric correction method based on WRF driven by NCEP FNL), Generic Atmospheric Correction Online Service for InSAR (GACOS), and ERA5—were used to evaluate the corrective effects of ERA5_WRF. The reliability of ERA5_WRF in different scenarios with large tropospheric delay was evaluated from the spatial and temporal perspectives by considering seasonal, topographic, and climatic factors. Its applications in the local space showed that ERA5_WRF could adequately correct tropospheric delay. Benefits include its high-quality data sources and the simulation of WRF, and its application in different seasons had proven superior to other methods in terms of the corrective effects of elevation-related and spatially related delays in summer. By analyzing the data sources and downscaling methods of correction methods and weather conditions of cases, ERA5_WRF had superior performance under the condition of large content and hourly variation of tropospheric delay. Furthermore, WRF showed the potential for tropospheric correction when other higher-quality data appear in the future.
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spelling doaj.art-8d1c456d2fff4255aaa3e2c0830f452e2023-12-02T00:52:18ZengMDPI AGRemote Sensing2072-42922023-01-0115127310.3390/rs15010273Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for InitializationQinghua Liu0Qiming Zeng1Zhiliang Zhang2Institute of Remote Sensing and Geographic Information System, Peking University, Beijing 100871, ChinaInstitute of Remote Sensing and Geographic Information System, Peking University, Beijing 100871, ChinaInstitute of Remote Sensing and Geographic Information System, Peking University, Beijing 100871, ChinaThe delay caused by the troposphere is one of the major sources of errors limiting the accuracy of InSAR measurements. The tropospheric correction of InSAR measurements is important. The Weather Research and Forecasting (WRF) Model is a state-of-the-art mesoscale numerical weather prediction system designed for atmospheric research applications. It can be applied to InSAR tropospheric correction. Its parameters can be altered according to the requirements of the given application. WRF is usually initialized based on 3 h- or 6 h temporal resolution data in InSAR tropospheric correction studies, a lower temporal resolution compared to ERA5 data. A lower time resolution means a longer integration time for WRF to simulate from the initial time to the target time. Initialization with a higher resolution can shorten the integration time of the simulation theoretically and improve its accuracy. However, an evaluation of the effectiveness of ERA5_WRF for InSAR tropospheric correction is lacking. To evaluate the efficiency of WRF tropospheric correction, we used Reanalysis v5 (ERA5) from the European Centre for Medium-Range Weather Forecasts (ECMWF) for initialization to drive the WRF (ERA5_WRF) for efficient applications in InSAR. Three methods based on global atmospheric models—FNL_WRF (tropospheric correction method based on WRF driven by NCEP FNL), Generic Atmospheric Correction Online Service for InSAR (GACOS), and ERA5—were used to evaluate the corrective effects of ERA5_WRF. The reliability of ERA5_WRF in different scenarios with large tropospheric delay was evaluated from the spatial and temporal perspectives by considering seasonal, topographic, and climatic factors. Its applications in the local space showed that ERA5_WRF could adequately correct tropospheric delay. Benefits include its high-quality data sources and the simulation of WRF, and its application in different seasons had proven superior to other methods in terms of the corrective effects of elevation-related and spatially related delays in summer. By analyzing the data sources and downscaling methods of correction methods and weather conditions of cases, ERA5_WRF had superior performance under the condition of large content and hourly variation of tropospheric delay. Furthermore, WRF showed the potential for tropospheric correction when other higher-quality data appear in the future.https://www.mdpi.com/2072-4292/15/1/273InSARtropospheric correctionWRFERA5GACOS
spellingShingle Qinghua Liu
Qiming Zeng
Zhiliang Zhang
Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization
Remote Sensing
InSAR
tropospheric correction
WRF
ERA5
GACOS
title Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization
title_full Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization
title_fullStr Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization
title_full_unstemmed Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization
title_short Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization
title_sort evaluation of insar tropospheric correction by using efficient wrf simulation with era5 for initialization
topic InSAR
tropospheric correction
WRF
ERA5
GACOS
url https://www.mdpi.com/2072-4292/15/1/273
work_keys_str_mv AT qinghualiu evaluationofinsartroposphericcorrectionbyusingefficientwrfsimulationwithera5forinitialization
AT qimingzeng evaluationofinsartroposphericcorrectionbyusingefficientwrfsimulationwithera5forinitialization
AT zhiliangzhang evaluationofinsartroposphericcorrectionbyusingefficientwrfsimulationwithera5forinitialization