Assessment of Atmospheric Propagation Effects in SAR Images

Danklmayer, Andreas; Döring, Björn; Schwerdt, Marco; Chandra, Madhu

doi:10.1109/tgrs.2009.2022271

Cited by 101 publications

(58 citation statements)

References 20 publications

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“…3). Nevertheless, due to the mountainous topography and to the high degree of humidity that characterize the Azorean Islands, backscattering intensity and interferometric coherence [van Zyl, 1993;van Zyl et al, 1993;Castel et al, 2002;Danklmayer et al, 2009] are affected when using Synthetic Aperture Radar (SAR) sensors in this type of environments. That's the reason why the Sentinel 1 Mission (high-resolution microwave imaging) products could not represent an effective and fully reliable solution in order to be integrated and implemented into the "GMES Azorean Regional Framework".…”

Section: Resultsmentioning

confidence: 99%

Linking GMES Space Component to the development of land policies in Outermost Regions—the Azores (Portugal) case-study

Gil

Fonseca

Lobo

et al. 2012

European Journal of Remote Sensing

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The aim of this study is to assess the potential effectiveness of GMES Space Component Sentinel Missions for land-based environmental policy support in the Azores Autonomous Region (Portugal). Sixteen different types of legal and spatial instruments are currently being applied in this region. Most of them require detailed and accurate Land-use/Landcover cartography in order to deliver reliable outputs at municipal, island and archipelagic scales. Sentinel-2 Mission products can fulfill these requirements in a cost-effective way. A Spatial Data Infrastructure-based Regional GMES framework is proposed in order to process, assess, validate and integrate this GMES data into the decision support system of Azorean regional land policies.

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Section: Resultsmentioning

confidence: 99%

Linking GMES Space Component to the development of land policies in Outermost Regions—the Azores (Portugal) case-study

Gil

Fonseca

Lobo

et al. 2012

European Journal of Remote Sensing

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“…A previous research by Hanssen et al (2001) mentioned that, in case of SAR interferometry with higher radar frequency such as X-band and C-band, strong absorption of microwave energy due to severe cloud cover is likely to occur, resulting in missing observation under such a situation. On the other hand, L-band SAR interferometry is little attenuated by cloud hydrometeors (Danklmayer et al 2009). This cloud-free characteristic is one of the advantages of L-band InSAR among other vertically integrated water vapor observation techniques.…”

Section: Discussionmentioning

confidence: 99%

Detections and simulations of tropospheric water vapor fluctuations due to trapped lee waves by ALOS-2/PALSAR-2 ScanSAR interferometry

Kinoshita

Morishita

Hirabayashi

2017

Earth Planets Space

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Detailed wave-like spatial patterns of atmospheric propagation delay signals associated with mountain lee waves were detected in Hokkaido and Tohoku by synthetic aperture radar (SAR) interferometry (InSAR) with the ScanSAR mode observation data of a Phased Array-type L-band Synthetic Aperture Radar 2 on board the Advanced Land Observing Satellite 2. Both cases occurred under stable atmosphere conditions. The InSAR-observed peak-to-trough line of sight changes in the mountain wave signals was 4 and 5 cm with the horizontal wavelengths of 9 and 15 km in Hokkaido and Tohoku, respectively. Locations of positive phase maxima in the mountain wave signals coincides with locations of cloud streets observed by visible satellite imagery, indicating that crests of mountain waves contain relatively much water vapor compared with wave troughs. Numerical weather simulations with the horizontal grid spacing of 1 km were performed to reproduce InSAR phase variations, and as a result those simulations could reasonably reproduce observed wave amplitudes and wavelengths in both cases. On the other hand, numerical simulations tended to overestimate wave attenuation rates: simulated mountain waves decreased as the wave propagated faster than those of observed signals. Because the simulated wave attenuation rate is sensitive to physics in the planetary boundary layer (PBL), we investigated the reproducibility of five PBL schemes implemented in the WRF model. As a result, all the PBL schemes showed little attenuation except for the Yonsei University scheme (YSU), while the wavelength in the YSU was most close to the observation. Our study demonstrated the uniqueness and usefulness of InSAR for meteorological application as the ability to map the detailed water vapor distribution regardless of cloud cover. In addition, the reasonable reproducibility of the water vapor delay signal due to lee waves by the numerical weather model encourages researchers who tackle the correction of the tropospheric propagation delay, increasing the accuracy in detecting surface deformations.

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“…Differential Synthetic Aperture RADAR Interferometry or DInSAR is used in remote sensing for measuring Earth surface deformation (Doin et al, 2009). This technique is considered more accurate than InSAR as it is capable of providing relative measures up to few centimetres or less (Danklmayer et al, 2009). When an interferogram is formed from two SAR images, and a Digital elevation Model (DEM) to simulate and remove phase changes due to topography, a new phase image is formed (Gabriel et al, 1989).…”

Section: Atmospheric Effects On Insarmentioning

confidence: 99%

Atmospheric Phase Delay in Sentinel Sar Interferometry

Krishnakumar¹,

Monserrat²,

Crosetto³

et al. 2018

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Commission III, WG III/3 KEY WORDS: Interferometric SAR, differential interferometry, tropospheric path delay ABSTRACT:The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR) Interferometry (InSAR) has been a widely used geodetic technique for observing the Earth's surface, especially for mapping the Earth's topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth's atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere) are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC) of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR). To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET) and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC) images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate height and deformation measurements.

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Assessment of Atmospheric Propagation Effects in SAR Images

Abstract: A test case showing a comparison of TerraSAR-X and ground-based weather radar data acquired nearly simultaneously (within the same minute) over New York City. A good agreement between rain-cell signatures in (left) the SAR image and (right) the weather radar image can be observed.

Cited by 101 publications

References 20 publications

Linking GMES Space Component to the development of land policies in Outermost Regions—the Azores (Portugal) case-study

Linking GMES Space Component to the development of land policies in Outermost Regions—the Azores (Portugal) case-study

Detections and simulations of tropospheric water vapor fluctuations due to trapped lee waves by ALOS-2/PALSAR-2 ScanSAR interferometry

Atmospheric Phase Delay in Sentinel Sar Interferometry

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