Time-series displacement from high-resolution satellite Synthetic Aperture Radar (SAR) data using Sub-Pixel Offset Tracking (SPOT)

Time-series displacements at Merapi volcano, Indonesia, from high-resolution SAR and sub-pixel offset tracking (SPOT). When using this dataset, please cite the authors: Bemelmans, Mark^1,2,+; Biggs, Juliet^1,2; Wookey, James^1; Poland, Michael^3. 1: School of Earth Sciences, University of Bristol, Bristol, United Kingdom. 2: Centre for the Observation and Modelling of Volcanoes, Earthquakes, and Tectonics (COMET), United Kingdom. 3: Cascades Volcano Observatory (CVO), U.S. Geological Survey (USGS), Vancouver, Washington, The United States. +: corresponding author, [email protected] *Work is currently in preparation and will be updated when publication information is known.* Background Information: Synthetic Aperture Radar (SAR) data are collected through the Centre for Earth Observation Satellites (CEOS). The COSMO-Skymed (CSK) data are owned by the Italian Space Agency (ISO) and the TerraSAR-X (TSX) data are owned by the Deutsche Lüft- und Raumfarht Centrum (DLR). Additionally, the Digital Elevation Model (DEM) used to correct for parallax shift is from Thomas and Darmawan, 2021. (High-resolution Digital Elevation Model of Merapi summit in 2015 generated by UAVs and TLS and TanDEM-X. The data are processed using GAMMA-rs (Werner et al., 2000) using Sub-Pixel Offset Tracking (SPOT). SPOT uses image cross-correlation of small image patches to extract displacements (offsets) to sub-pixel precision. Details of the data processing can be found in [Bemelmans et al., in prep] This data set currently includes data from CSK (heading 168 deg., incidence angel 35.6 deg., image resolution 0.34 in slant range, 0.70 in azimuth) with the following dates: 20200910 20200919 20200926 20200927 20201005 20201012 20201013 20201113 20201114 20201122 20201224 20201231 20210101 20210109 20210116 20210117 20210125 20210201 20210202 20210217 20210218 20210302 20210305 20210306 20210314 20210321 20210322 20210330 20210406 20210419 20210422 20210423 20210501 20210508 20210509 20210521 20210609 20210711 20210720 20210727 20210728 20210812 20210813 20210829 20210910 20210913 20210914 20210922 20210926 20210930 20211015 20211016 20211024 20211031 20211101 We also have data from TSX (heading 191 deg., incidence angle 37.6 deg., image resolution 0.45 m in slant range, 0.17 m in azimuth). We have acquisitions from the following dates: 20201116 20201127 20201208 20201219 20210110 20210201 20210223 20210317 20210408 20210430 20210522 20210602 20210613 20211001 20211023 For each acquisition we process pixel offsets to the 3 adjacent acquisitions. We then select the pixels for which we have 1 connected network of acquisition pairs that cover all the dates in the time series. We use (unweighted) least-squares inversion to extract the time series. This dataset contains the following two files: - CSK_SPOT_dsc_win13_ts_inv.csv (containing 282,270 points) - TSX_ST134_win13_ts_inv.csv (containing 48,291 points) CSK_SPOT_dsc_win13_ts_inv.csv contains the time series pixel offsets from the CSK data in the slant range and azimuth directions (in meters). TSX_ST134_win13_ts_inv.csv contains the time series pixel offsets from the TSX data in the slant range and azimuth directions (in meters). The Data has the following format: Row id | Longitude [deg. E] | Latitude [deg. N] | range disp. Date 1 [m] | azimuth disp. Date 1 [m] | range disp.Date 2 [m] | azimuth disp. Date 2 [m] | ... 0 110.4641 -7.5363 0 0 0.003 0.050 1 110.4639 -7.5363 0 0 0.004 0.077 2 110.4638 -7.5364 0 0 0.047 0.081 3 110.4637 -7.5364 0 0 0.054 -0.027 4 110.4634 -7.5365 0 0 0.041 -0.002 5 110.4633 -7.5365 0 0 0.037 0.022 Note: in this dataset, row id refers to the row index of the original dataset which was filtered for data we could not make a complete time -series for and is not of any use for further interpretation.