Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.3390/rs10101514 |
Radar Path Delay Effects in Volcanic Gas Plumes: The Case of Lascar Volcano, Northern Chile | |
Bredemeyer, Stefan1; Ulmer, Franz-Georg2; Hansteen, Thor H.1; Walter, Thomas R.3 | |
通讯作者 | Bredemeyer, Stefan |
来源期刊 | REMOTE SENSING
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ISSN | 2072-4292 |
出版年 | 2018 |
卷号 | 10期号:10 |
英文摘要 | Modern volcano monitoring commonly involves Interferometric Synthetic Aperture Radar (InSAR) measurements to identify ground motions caused by volcanic activity. However, InSAR is largely affected by changes in atmospheric refractivity, in particular by changes which can be attributed to the distribution of water (H2O) vapor in the atmospheric column. Gas emissions from continuously degassing volcanoes contain abundant water vapor and thus produce variations in the atmospheric water vapor content above and downwind of the volcano, which are notably well captured by short-wavelength X-band SAR systems. These variations may in turn cause differential phase errors in volcano deformation estimates due to excess radar path delay effects within the volcanic gas plume. Inversely, if these radar path delay effects are better understood, they may be even used for monitoring degassing activity, by means of the precipitable water vapor (PWV) content in the plume at the time of SAR acquisitions, which may provide essential information on gas plume dispersion and the state of volcanic and hydrothermal activity. In this work we investigate the radar path delays that were generated by water vapor contained in the volcanic gas plume of the persistently degassing Lascar volcano, which is located in the dry Atacama Desert of Northern Chile. We estimate water vapor contents based on sulfur dioxide (SO2) emission measurements from a scanning UV spectrometer (Mini-DOAS) station installed at Lascar volcano, which were scaled by H2O/SO2 molar mixing ratios obtained during a multi-component Gas Analyzer System (Multi-GAS) survey on the crater rim of the volcano. To calculate the water vapor content in the downwind portion of the plume, where an increase of water vapor is expected, we further applied a correction involving estimation of potential evaporation rates of water droplets governed by turbulent mixing of the condensed volcanic plume with the dry atmosphere. Based on these estimates we obtain daily average PWV contents inside the volcanic gas plume of 0.2-2.5 mm equivalent water column, which translates to a slant wet delay (SWD) in DInSAR data of 1.6-20 mm. We used these estimates in combination with our high resolution TerraSAR-X DInSAR observations at Lascar volcano, in order to demonstrate the occurrence of repeated atmospheric delay patterns that were generated by volcanic gas emissions. We show that gas plume related refractivity changes are significant and detectable in DInSAR measurements. Implications are two-fold: X-band satellite radar observations also contain information on the degassing state of a volcano, while deformation signals need to be interpreted with care, which has relevance for volcano observations at Lascar and for other sites worldwide. |
英文关键词 | gas emission monitoring X-band InSAR scanning Mini-DOAS Multi-GAS volcanic gases precipitable water vapor radar path delay Lascar volcano |
类型 | Article |
语种 | 英语 |
国家 | Germany |
收录类别 | SCI-E |
WOS记录号 | WOS:000448555800014 |
WOS关键词 | SOUFRIERE-HILLS-VOLCANO ; WATER-VAPOR ; GROUND DEFORMATION ; CAMPI FLEGREI ; SURFACE DEFORMATION ; SAR INTERFEROMETRY ; PRECIPITABLE WATER ; KILAUEA VOLCANO ; IZU PENINSULA ; SO2 |
WOS类目 | Remote Sensing |
WOS研究方向 | Remote Sensing |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/212657 |
作者单位 | 1.GEOMAR Helmholtz Ctr Ocean Res Kiel, Res Div Dynam Ocean Floor 4, Wischhofstr 1-3, D-24148 Kiel, Germany; 2.German Aerosp Ctr DLR, Remote Sensing Technol Inst, D-82234 Oberpaffenhofen, Wessling, Germany; 3.GFZ German Res Ctr Geosci, Sect Phys Volcanoes & Earthquakes 2 1, D-14473 Potsdam, Germany |
推荐引用方式 GB/T 7714 | Bredemeyer, Stefan,Ulmer, Franz-Georg,Hansteen, Thor H.,et al. Radar Path Delay Effects in Volcanic Gas Plumes: The Case of Lascar Volcano, Northern Chile[J],2018,10(10). |
APA | Bredemeyer, Stefan,Ulmer, Franz-Georg,Hansteen, Thor H.,&Walter, Thomas R..(2018).Radar Path Delay Effects in Volcanic Gas Plumes: The Case of Lascar Volcano, Northern Chile.REMOTE SENSING,10(10). |
MLA | Bredemeyer, Stefan,et al."Radar Path Delay Effects in Volcanic Gas Plumes: The Case of Lascar Volcano, Northern Chile".REMOTE SENSING 10.10(2018). |
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