Mitigation of atmospheric phase delay effects in SAR interferometry for volcanic activity monotoring using MODIS data and WRF model

2012 ◽  
Author(s):  
Jungkyo Jung ◽  
Duk-jin Kim
Keyword(s):  
Volcanic Activity ◽  
Wrf Model ◽  
Phase Delay ◽  
Sar Interferometry ◽  
Modis Data ◽  
Delay Effects

On the Use of the WRF Model to Mitigate Tropospheric Phase Delay Effects in SAR Interferograms

2011 ◽  
Vol 49 (12) ◽  
pp. 4970-4976 ◽  
Author(s):  
G. Nico ◽  
R. Tome ◽  
J. Catalao ◽  
P. M. A. Miranda
Keyword(s):  
Wrf Model ◽  
Phase Delay ◽  
Delay Effects

Remote sensing of steep-slope volcanoes: the Stromboli case study

2021 ◽  
Author(s):  
Federico Di Traglia ◽  
Claudio De Luca ◽  
Alessandro Fornaciai ◽  
Mariarosaria Manzo ◽  
Teresa Nolesini ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Volcanic Activity ◽  
Ground Deformation ◽  
Steep Slope ◽  
Sar Interferometry ◽  
Large Set ◽  
Multi Temporal ◽  
Optical Imagery ◽  
Gravitational Processes ◽  
Sciara Del Fuoco

<p>Steep-slope volcanoes are geomorphological systems receptive to both exogenous and endogenous phenomena. Volcanic activity produces debris and lava accumulation, whereas magmatic/tectonic and gravitational processes can have a destructive effect, triggering mass-wasting and erosion.</p><p>Optical and radar sensors have often been used to identify areas impacted by eruptive and post-eruptive phenomena, quantify of topographic changes, and/or map ground deformation related to magmatic-tectonic-gravitational processes.</p><p>In this work, the slope processes on high-gradient volcano flanks in response to shift in volcanic activity have been identified by means of remote sensing techniques. The Sciara del Fuoco unstable flank of Stromboli volcano (Italy) was studied, having a very large set (2010-2020) of different remote sensing data available.</p><p>Data includes LiDAR and tri-stereo PLEIADES-1 DEMs, high-spatial-resolution (HSR) optical imagery (QUICKBIRD and PLEIADES-1), and space-borne and ground-based Synthetic Aperture Radar (SAR) data. Multi-temporal DEMs and HSR optical imagery permits to map areas affected by major lithological and morphological changes, and the volumes of deposited/eroded material. The results lead to the identification of topographical variations and geomorphological processes that occurred in response to the variation in eruptive intensity. The joint exploitation of space-borne and ground-based Differential and Multi Temporal SAR Interferometry (InSAR and MT-InSAR) measurements revealed deformation phenomena affecting the volcano edifice, and in particular the Sciara del Fuoco flank.</p><p>The presented results demonstrate the effectiveness of the joint exploitation of multi-temporal DEMs, HSR optical imagery, and InSAR measurements obtained through satellite and terrestrial SAR systems, highlighting their strong complementarity to map and interpret the slope phenomena in volcanic areas.</p><p>This work was financially supported by the “Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile” (Presidency of the Council of Ministers – Department of Civil Protection); this publication, however, does not reflect the position and official policies of the Department".</p>

scholarly journals Effect of Initiation Location within Blasthole on Blast Vibration Field and Its Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Qidong Gao ◽  
Wenbo Lu ◽  
Zhendong Leng ◽  
Zhaowei Yang ◽  
Yuzhu Zhang ◽  
...  
Keyword(s):  
Detonation Wave ◽  
Forward Direction ◽  
Phase Delay ◽  
Cylindrical Charge ◽  
Blast Vibration ◽  
Vibration Field ◽  
Delay Effects ◽  
Acting Mechanism ◽  
Experimental Approaches ◽  
Drill And Blast

In drill and blast, the explosive filled in each blasthole is cylindrically shaped and generally initiated by the detonator. Thus, the effect of the initiation location must be addressed, as it determines the detonation direction along the entire column explosive. In this paper, the effect of the initiation location on blast vibration field and its acting mechanism were comprehensively investigated through the theoretical, computational, and experimental approaches. The results indicate that the initiation location plays an important role in the blast vibration filed of the cylindrical charge. The underlying effect of the initiation location can be regarded as the combined results of the energy distribution and phase delay effects of the column explosive source. The behavior of the rock mass in the single-hole blasting experiment demonstrates that the explosion energy is preferentially transmitted to the forward direction of the detonation wave. The seed wave-based computation model verifies that owing to the phase delay effect, the blast vibration field of the cylindrical charge is not uniformly distributed and is strengthened at the forward direction of the detonation wave. The production blasting experiment indicates that the ground PPV under bottom initiation is 61.3%∼211.7% larger than that under top initiation. In addition, the effect of the initiation location is sensitive to the charge length L and the denotation velocity D. Meanwhile, the effect of the initiation location vanishes with distance. The present study provides valuable reference for understanding the effect of the initiation location on blast vibration in drill and blast.

scholarly journals Estimating the atmospheric phase delay for quantifying co-seismic deformation using repeat pass Differential SAR Interferometry: Observations from 20th April 2013 Lushan (China) Earthquake

2014 ◽  
Vol XL-8 ◽  
pp. 57-64 ◽  
Author(s):  
J. Mathew ◽  
R. Majumdar ◽  
K. Vinod Kumar
Keyword(s):  
Surface Deformation ◽  
Lushan Earthquake ◽  
Phase Delay ◽  
Sar Interferometry ◽  
Electron Content ◽  
Phase Component ◽  
Total Electron ◽  
China Earthquake ◽  
Delay Component ◽  
Seismic Deformation

Atmospheric phase contribution significantly influences co-seismic surface deformation estimates from repeat pass Differential Synthetic Aperture Radar Interferometry (DInSAR). Present study investigates the contribution of the atmosphere in co-seismic deformation estimation associated with the 20 April 2013 Lushan (China) earthquake. The Lushan Earthquake occurred in the south-western segment of the Longmenshan fault zone, on the eastern margin of the Qinghai-Tibetan Plateau. Using pre- and postearthquake Radarsat-2 interferometric pair, the co-seismic deformation of the Lushan earthquake has been estimated. The tropospheric phase delay component has been estimated using tropospheric models in conjunction with surface temperature and pressure data from MODIS atmospheric products. The ionospheric phase component has been computed using the Total Electron Content (TEC) data. The net atmospheric path addition in the study area varies from 3.022 m to 4.621 m for the pre-earthquake SAR acquisition and from 2.687 m to 4.199 m for the post-event data acquisition. Comparison of the Line of Sight (LOS) displacement values computed using un-corrected and corrected interferometric data shows that the atmospheric phase component has introduced considerable contribution in the LOS displacement values. The uncorrected LOS displacement values vary from 0.902 m to −0.157 m where as those from the phase-corrected interferometric data are in the range of 0.052 m and −0.062 m. The corrected LOS displacement values show close agreement to a few GPS based co-seismic surface deformation components from published literature. Thus removal of atmospheric phase contribution is a necessary step in using repeat pass DInSAR for co-seismic surface deformation estimation.

scholarly journals Investigation of the Effects of Different Land Use and Land Cover Patterns on Mesoscale Meteorological Simulations in the Taiwan Area

2013 ◽  
Vol 52 (3) ◽  
pp. 570-587 ◽  
Author(s):  
Fang-Yi Cheng ◽  
Yu-Ching Hsu ◽  
Pay-Liam Lin ◽  
Tang-Huang Lin
Keyword(s):  
Land Use ◽  
Wind Speed ◽  
Roughness Length ◽  
Surface Wind ◽  
Wrf Model ◽  
Surface Wind Speed ◽  
Sea Breezes ◽  
Modis Data ◽  
Wind Speeds ◽  
Moderate Resolution Imaging Spectroradiometer

AbstractThe U.S. Geological Survey (USGS) land use (LU) data employed in the Weather Research and Forecasting (WRF) model classify most LU types in Taiwan as mixtures of irrigated cropland and forest, which is not an accurate representation of current conditions. The WRF model released after version 3.1 provides an alternative LU dataset retrieved from 2001 Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products. The MODIS data correctly identify most LU-type distributions, except that they represent western Taiwan as being extremely urbanized. A new LU dataset, obtained using 2007 Système Probatoire d’Observation de la Terre (SPOT) satellite imagery [from the National Central University of Taiwan (NCU)], accurately shows the major metropolitan cities as well as other land types. Three WRF simulations were performed, each with a different LU dataset. Owing to the overestimation of urban area in the MODIS data, WRF-MODIS overpredicts daytime temperatures in western Taiwan. Conversely, WRF-USGS underpredicts daytime temperatures. The temperature variation estimated by WRF-NCU falls between those estimated by the other two simulations. Over the ocean, WRF-MODIS predicts the strongest onshore sea breezes, owing to the enhanced temperature gradient between land and sea, while WRF-USGS predicts the weakest onshore flow. The intensity of the onshore breeze predicted by WRF-NCU is between those predicted by WRF-MODIS and WRF-USGS. Over Taiwan, roughness length is the key parameter influencing wind speed. WRF-USGS significantly overpredicts the surface wind speed owing to the shorter roughness length of its elements, while the surface wind speeds estimated by WRF-NCU and WRF-MODIS are in better agreement with the observed data.

scholarly journals RSTVOLC implementation on MODIS data for monitoring of thermal volcanic activity

2011 ◽  
Vol 54 (5) ◽  
Author(s):  
Teodosio Lacava ◽  
Francesco Marchese ◽  
Nicola Pergola ◽  
Valerio Tramutoli ◽  
Irina Coviello ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Hot Spots ◽  
Hot Spot ◽  
Mount Etna ◽  
Satellite Monitoring ◽  
Modis Data ◽  
Spot Detection ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

An optimized configuration of the Robust Satellite Technique (RST) approach was developed within the framework of the ‘LAVA’ project. This project is funded by the Italian Department of Civil Protection and the Italian Istituto Nazionale di Geofisica e Vulcanologia, with the aim to improve the effectiveness of satellite monitoring of thermal volcanic activity. This improved RST configuration, named RSTVOLC, has recently been implemented in an automatic processing chain that was developed to detect hot-spots in near real-time for Italian volcanoes. This study presents the results obtained for the Mount Etna eruption of July 14-24, 2006, using the Moderate Resolution Imaging Spectroradiometer (MODIS) data. To better assess the operational performance, the RSTVOLC results are also discussed in comparison with those obtained by MODVOLC, a well-established, MODIS-based algorithm for hot-spot detection that is used worldwide.

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