Corrections of stratified tropospheric delays in SAR interferometry: Validation with global atmospheric models

Doin, Marie‐Pierre; Lasserre, Cécile; Peltzer, G.; Cavalié, Olivier; Doubre, Cécile

doi:10.1016/j.jappgeo.2009.03.010

Cited by 348 publications

(320 citation statements)

References 47 publications

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“…Image pairs were selected by spatial and temporal baselines: (i) B t < 1 year and B s < 500 m; (ii) B t < 3 year and B s < 300 m; and (iii) B t < 5 year and B s < 100 m (Figure 2). In ascending track 298, the 10 October 2005data extends the time baseline from 2 to 5 years, which is significant for co-registering images [33], which improved the interferometric processing and increased the coherence of interferograms. During SAR data processing, we multilooked the SAR images 4 and 20 times in the azimuth and range directions, respectively, during processing to improve the signal-to-noise ratio.…”

Section: Insar Data and Processingmentioning

confidence: 99%

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Zhu

Wen

et al. 2016

Remote Sensing

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Abstract:The Altyn Tagh Fault (ATF) is one of the major left-lateral strike-slip faults in the northeastern area of the Tibetan Plateau. In this study, the interseismic deformation across the ATF at 85˝E was measured using 216 interferograms from 33 ENVISAT advanced synthetic aperture radar images on a descending track acquired from 2003 to 2010, and 66 interferograms from 15 advanced synthetic aperture radar images on an ascending track acquired from 2005 to 2010. To retrieve the pattern of interseismic strain accumulation, a global atmospheric model (ERA-Interim) provided by the European Center for Medium Range Weather Forecast and a global network orbital correction approach were applied to remove atmospheric effects and the long-wavelength orbital errors in the interferograms. Then, the interferometric synthetic aperture radar (InSAR) time series with atmospheric estimation model was used to obtain a deformation rate map for the ATF. Based on the InSAR velocity map, the regional strain rates field was calculated for the first time using the multi-scale wavelet method. The strain accumulation is strongly focused on the ATF with the maximum strain rate of 12.4ˆ10´8/year. We also show that high-resolution 2-D strain rates field can be calculated from InSAR alone, even without GPS data. Using a simple half-space elastic screw dislocation model, the slip-rate and locking depth were estimated with both ascending and descending surface velocity measurements. The joint inversion results are consistent with a left-lateral slip rate of 8.0˘0.7 mm/year on the ATF and a locking depth of 14.5˘3 km, which is in agreement with previous results from GPS surveys and ERS InSAR results. Our results support the dynamic models of Asian deformation requiring low fault slip rate.

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Section: Insar Data and Processingmentioning

confidence: 99%

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Zhu

Wen

et al. 2016

Remote Sensing

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“…To estimate the magnitude of the atmospheric signals that we should expect to see in interferograms produced from our data set, we estimated phase delay maps using the ERA-Interim (ERA-I) global atmospheric model reanalysis product [Dee et al, 2011] obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF). To estimate the combined delay from differences in water vapor (wet delay) and atmospheric pressure (hydrostatic delay), we first created delay maps using the method of Doin et al [2009] andJolivet et al [2011]. The ERA-I atmospheric model provides estimates of 16 meteorological parameters including temperature, relative humidity, and geopotential at 6 h intervals from 1989 onward.…”

Section: Atmospheric Correction Of Interferogramsmentioning

confidence: 99%

Constraining crustal velocity fields with InSAR for Eastern Turkey: Limits to the block‐like behavior of Eastern Anatolia

2014

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The Sentinel-1 satellite mission will enable global strain rate mapping from interferometric synthetic aperture radar (InSAR) and GPS data, and methods to combine these data in velocity fields will become increasingly important. Here we use InSAR to measure interseismic deformation in Eastern Turkey, across a ∼250,000 km 2 area that spans the Arabia-Eurasia plate boundary zone. From our InSAR data we first estimate slip rates and locking depths for the North and East Anatolian Faults (NAF and EAF) of 20 ± 3 mm/yr and ∼16 km and 11 ± 3 mm/yr and ∼16 km, respectively, but we also combine the InSAR data with existing GPS velocity measurements to construct high-resolution velocity and strain rate fields across the region for the first time. We calculate 2-D and 3-D velocity fields and find that strain is mainly localized across the NAF and EAF and that there is negligible differential vertical motion across the Eastern Anatolian plateau. We also show that high-resolution 2-D strain rate fields can be calculated from InSAR alone, even in the absence of GPS data. We fit a block model to our velocity field and estimate slip rates of ∼21 mm/yr and ∼8 mm/yr for the NAF and EAF, showing that our previous estimates differ from these values because they neglected crustal rotation. Although this rotation is an important component of the velocity field in Eastern Turkey, systematic residuals between our velocity field and the best fitting block for Anatolia suggest that the region is not block-like as proposed by previous authors.

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“…To estimate the magnitude of the atmospheric signals we should expect to see in interferograms produced from our data set (Table 1), we estimated phase delay maps using the ERA-Interim global atmospheric model [Dee et al, 2011] obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF). To estimate the combined delay from differences in water vapor (wet delay) and atmospheric pressure (dry delay), we first created delay maps using the method of Doin et al [2009] andJolivet et al [2011]. The ERA-Interim atmospheric model provides estimates of 16 meteorological parameters including temperature, relative humidity, and geopotential, at 6 h intervals from 1989 onward.…”

Section: Construction Of Interferograms and Atmospheric Contaminationmentioning

confidence: 99%

“…[21] Tropospheric pressure differences also make a significant contribution to SAR phase delay [Elliott et al, 2008;Doin et al, 2009]. The absolute delay from this hydrostatic or "dry" part of the atmosphere is greater than the "wet" delay for any single acquisition date, but the wet delay is more variable between dates and so has a greater contribution to radar phase delay in interferograms [Zebker et al 1997].…”

Section: The Meris Atmospheric Correctionmentioning

confidence: 99%

Rapid strain accumulation on the Ashkabad fault (Turkmenistan) from atmosphere‐corrected InSAR

Walters

Elliott

et al. 2013

JGR Solid Earth

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[1] We have measured interseismic deformation across the Ashkabad strike-slip fault using 13 Envisat interferograms covering a total effective timespan of 30 years. Atmospheric contributions to phase delay are significant and variable due to the close proximity of the Caspian Sea. In order to retrieve the pattern of strain accumulation, we show it is necessary to use data from Envisat's Medium-Resolution Imaging Spectrometer (MERIS) instrument, as well as numerical weather model outputs from the European Centre for Medium-Range Weather Forecasts (ECMWF), to correct interferograms for differences in water vapor and atmospheric pressure, respectively. This has enabled us to robustly estimate the slip rate and locking depth for the Ashkabad fault using a simple elastic dislocation model. Our data are consistent with a slip rate of 5-12 mm/yr below a locking depth of 5.5-17 km for the Ashkabad fault, and synthetic tests support the magnitude of the uncertainties on these estimates. Our estimate of slip rate is 1.25-6 times higher than some previous geodetic estimates, with implications for both seismic hazard and regional tectonics, in particular supporting fast relative motion between the South Caspian Block and Eurasia. This result reinforces the importance of correcting for atmospheric contributions to interferometric phase for small strain measurements. We also attempt to validate a recent method for atmospheric correction based on ECMWF ERA-Interim model outputs alone and find that this technique does not work satisfactorily for this region when compared to the independent MERIS estimates.

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Corrections of stratified tropospheric delays in SAR interferometry: Validation with global atmospheric models

Cited by 348 publications

References 47 publications

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Constraining crustal velocity fields with InSAR for Eastern Turkey: Limits to the block‐like behavior of Eastern Anatolia

Rapid strain accumulation on the Ashkabad fault (Turkmenistan) from atmosphere‐corrected InSAR

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