scholarly journals Forest mapping and monitoring with interferometric synthetic aperture radar (InSAR)

2001 ◽  
Vol 25 (2) ◽  
pp. 159-177 ◽  
Author(s):  
H. Balzter
Keyword(s):  
Synthetic Aperture Radar ◽  
Electromagnetic Waves ◽  
Forest Canopy ◽  
Thermal State ◽  
Time Lag ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Dimensional Structure ◽  
Forest Mapping ◽  
Aperture Radar

A synthetic aperture radar (SAR) is an active sensor transmitting pulses of polarized electromagnetic waves and receiving the backscattered radiation. SAR sensors at different wavelengths and with different polarimetric capabilities are being used in remote sensing of the earth. The value of an analysis of backscattered energy alone is limited due to ambiguities in the possible ecological factor configurations causing the signal. From two SAR images taken from similar viewing positions with a short time-lag, interference between the two waves can be observed. By subtracting the two phases of the signals, it is feasible to eliminate the random contribution of the scatterers to the phase. The interferometric correlation and the interferometric phase contain additional information on the three-dimensional structure of the scattering elements in the imaged area. A brief review of SAR sensors is given, followed by an outline of the physical foundations of SAR interferometry and the practical data-processing steps involved. An overview of applications of InSAR to forest mapping and monitoring is given, covering tree-bole volume and biomass, forest types and land cover, fire scars, forest thermal state and forest canopy height.

scholarly journals Assessing Forest/Non-Forest Separability Using Sentinel-1 C-Band Synthetic Aperture Radar

2020 ◽  
Vol 12 (11) ◽  
pp. 1899 ◽  
Author(s):  
Johannes N. Hansen ◽  
Edward T. A. Mitchard ◽  
Stuart King
Keyword(s):  
Synthetic Aperture Radar ◽  
Open Data ◽  
Synthetic Aperture ◽  
Support Vector ◽  
High Temporal Resolution ◽  
K Nearest Neighbors ◽  
Worst Case ◽  
Forest Mapping ◽  
Study Sites ◽  
Aperture Radar

Synthetic Aperture Radar has a unique potential for continuous forest mapping as it is not affected by cloud cover. While longer wavelengths, such as L-band, are commonly used for forest applications, in this paper we assess the aptitude of C-band Sentinel-1 data for this purpose, for which there is much interest due to its high temporal resolution (five days) and “free, full, and open” data policy. We tested its ability to distinguish forest from non-forest in six study sites, located in Alaska, Colombia, Finland, Florida, Indonesia, and the UK. Using the time series for a full year significantly increases the classification accuracy compared to a single scene (a mean of 85 % compared to 77 % across the study sites for the best classifier). Our results show that we can further improve the mean accuracy to 87 % when only considering the annual mean and standard deviation of co-polarized (VV) and cross-polarized (VH) backscatter. In this case, separation accuracies of up to 93 % (in Finland) are possible, though in the worst case (Alaska), the highest possible accuracy using these variables was 80 % . The best overall performance was observed when using a Support Vector Machine classifier, outperforming random forest, k-Nearest-Neighbors, and Quadratic Discriminant Analysis. We further show that the small information content we found in the phase data is an artifact of terrain slope orientation and has a negligible impact on classifier performance. We conclude that for the purposes of forest mapping the smaller file size and easier to process GRD products are sufficient, unless the SLC products are used to compute the temporal coherence which was not tested in this study.

Transient active deformation in Tainan tableland using persistent scatterers SAR interferometry

2013 ◽  
Vol 184 (4-5) ◽  
pp. 441-450 ◽  
Author(s):  
Yu-Yia Wu ◽  
Jyr-Ching Hu ◽  
Geng-Pei Lin ◽  
Chung-Pai Chang ◽  
Hsin Tung ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Surface Deformation ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Uplift Rate ◽  
Active Deformation ◽  
Radar Images ◽  
Persistent Scatterers ◽  
Area North ◽  
Aperture Radar

Abstract Persistent scatterers SAR interferometry (PS-InSAR) was employed to monitor surface deformation in and around the Tainan tableland using 20 advanced synthetic aperture radar (ASAR) images from the ENVISAT satellite taken during the period from 2005 May 19 to 2008 September 25. In our study, we have found that the uplift rate of the northern Tainan tableland is faster than the southern tableland. The slant range displacement (SRD) rate for the area north along the precise leveling array is about 5 to 10 mm/yr with respect to the western edge of the Tainan tableland, whereas the SRD rate for the area south of the leveling array is about 1 to 5 mm/yr. In addition, the uplifted area extends eastward to the Tawan lowland with a maximum SRD rate of nearly 10 mm/yr, which is almost the same as the rate of the Tainan tableland. Results of this study differ from those suggested in previous researches that employed ERS-1/2 radar images taken from 1996 to 1999 and the differential interferometry synthetic aperture radar (D-InSAR) technique. Our findings indicated that the Tawan lowland no longer subsides with respect to the western edge of the Tainan tableland, and that both northern and southern areas are experiencing uplift.

scholarly journals Synthetic Aperture Radar (SAR) Interferometry for Assessing Wenchuan Earthquake (2008) Deforestation in the Sichuan Giant Panda Site

2014 ◽  
Vol 6 (7) ◽  
pp. 6283-6299 ◽  
Author(s):  
Fulong Chen ◽  
Huadong Guo ◽  
Natarajan Ishwaran ◽  
Wei Zhou ◽  
Ruixia Yang ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Wenchuan Earthquake ◽  
Giant Panda ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Aperture Radar

scholarly journals Fusion of SAR Interferometry and Polarimetry Methods for Landslide Reactivation Study, the Bureya River (Russia) Event Case Study

2021 ◽  
Vol 13 (24) ◽  
pp. 5136
Author(s):  
Valery Bondur ◽  
Tumen Chimitdorzhiev ◽  
Aleksey Dmitriev ◽  
Pavel Dagurov
Keyword(s):  
Synthetic Aperture Radar ◽  
Radar Data ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Line Of Sight ◽  
Scattering Mechanisms ◽  
Radar Images ◽  
Landslide Reactivation ◽  
Sbas Insar ◽  
Aperture Radar

In this paper, we demonstrate the estimation capabilities of landslide reactivation based on various SAR (Synthetic Aperture Radar) methods: Cloude-Pottier decomposition of Sentinel-1 dual polarimetry data, MT-InSAR (Multi-temporal Interferometric Synthetic Aperture Radar) techniques, and cloud computing of backscattering time series. The object of the study is the landslide in the east of Russia that took place on 11 December 2018 on the Bureya River. H-α-A polarimetric decomposition of C-band radar images not detected significant transformations of scattering mechanisms for the surface of the rupture, whereas L-band radar data show changes in scattering mechanisms before and after the main landslide. The assessment of ground displacements along the surface of the rupture in the 2019–2021 snowless periods was carried out using MT-InSAR methods. These displacements were 40 mm/year along the line of sight. The SBAS-InSAR results have allowed us to reveal displacements of great area in 2020 and 2021 snowless periods that were 30–40 mm/year along the line-of-sight. In general, the results obtained by MT-InSAR methods showed, on the one hand, the continuation of displacements along the surface of the rupture and on the other hand, some stabilization of the rate of landslide processes.

scholarly journals Combined Use of Optical and Synthetic Aperture Radar Data for REDD+ Applications in Malawi

Land ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 116 ◽  
Author(s):  
Manuela Hirschmugl ◽  
Carina Sobe ◽  
Janik Deutscher ◽  
Mathias Schardt
Keyword(s):  
Time Series ◽  
Land Cover ◽  
Synthetic Aperture Radar ◽  
Data Availability ◽  
Synthetic Aperture ◽  
Optical Data ◽  
Series Data ◽  
Forest Mapping ◽  
Sar Data ◽  
Aperture Radar

Recent developments in satellite data availability allow tropical forest monitoring to expand in two ways: (1) dense time series foster the development of new methods for mapping and monitoring dry tropical forests and (2) the combination of optical data and synthetic aperture radar (SAR) data reduces the problems resulting from frequent cloud cover and yields additional information. This paper covers both issues by analyzing the possibilities of using optical (Sentinel-2) and SAR (Sentinel-1) time series data for forest and land cover mapping for REDD+ (Reducing Emissions from Deforestation and Forest Degradation) applications in Malawi. The challenge is to combine these different data sources in order to make optimal use of their complementary information content. We compare the results of using different input data sets as well as of two methods for data combination. Results show that time-series of optical data lead to better results than mono-temporal optical data (+8% overall accuracy for forest mapping). Combination of optical and SAR data leads to further improvements: +5% in overall accuracy for land cover and +1.5% for forest mapping. With respect to the tested combination methods, the data-based combination performs slightly better (+1% overall accuracy) than the result-based Bayesian combination.

Glacier displacement on Comfortlessbreen, Svalbard, using 2-pass differential SAR interferometry (DInSAR) with a digital elevation model

Polar Record ◽  
2011 ◽  
Vol 48 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Nora Jennifer Schneevoigt ◽  
Monica Sund ◽  
Wiley Bogren ◽  
Andreas Kääb ◽  
Dan Johan Weydahl
Keyword(s):  
Synthetic Aperture Radar ◽  
Digital Elevation Model ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Synthetic Aperture Radar Interferometry ◽  
Glacier Terminus ◽  
Digital Elevation ◽  
Reference Images ◽  
Elevation Model ◽  
Aperture Radar

ABSTRACTDifferential synthetic aperture radar interferometry (DInSAR) exploits the coherence between the phases of two or more satellite synthetic aperture radar (SAR) scenes taken from the same orbit to separate the phase contributions from topography and movement by subtracting either phase. Hence pure terrain displacement can be derived without residual height information in it, but only the component of movement in line-of-sight direction is represented in a differential interferogram. Comfortlessbreen, a recently surging glacier, flows predominantly in this direction with respect to the European Remote Sensing satellites ERS-1 and ERS-2. Four C-band SAR scenes from spring 1996 were selected because of the high coherence between the respective pairs of the 1-day repeat-pass tandem mission of the ERS sensors. 2-pass DInSAR is performed in combination with a SPOT5 (Satéllite pour l'Observation de la Terre 5) SPIRIT (SPOT5 stereoscopic survey of Polar Ice: Reference Images and Topography) digital elevation model (DEM) from 2007. The different processing steps and intermediate image products, including unwrapping and generation of displacement maps, are detailed in order to convey the DInSAR processing chain to the beginner in the field of interferometry. Maximum horizontal displacements of 18 to 20 cm d−1 in ground range direction can be detected at the glacier terminus, while a few centimetres per day characterised most of the middle and upper portions of Comfortlessbreen in spring 1996.

scholarly journals LiCSAR: An Automatic InSAR Tool for Measuring and Monitoring Tectonic and Volcanic Activity

2020 ◽  
Vol 12 (15) ◽  
pp. 2430 ◽  
Author(s):  
Milan Lazecký ◽  
Karsten Spaans ◽  
Pablo J. González ◽  
Yasser Maghsoudi ◽  
Yu Morishita ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Data Storage ◽  
Large Scale ◽  
Surface Deformation ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Online Portal ◽  
Processing And Storage ◽  
Update Strategy ◽  
Aperture Radar

Space-borne Synthetic Aperture Radar (SAR) Interferometry (InSAR) is now a key geophysical tool for surface deformation studies. The European Commission’s Sentinel-1 Constellation began acquiring data systematically in late 2014. The data, which are free and open access, have global coverage at moderate resolution with a 6 or 12-day revisit, enabling researchers to investigate large-scale surface deformation systematically through time. However, full exploitation of the potential of Sentinel-1 requires specific processing approaches as well as the efficient use of modern computing and data storage facilities. Here we present Looking Into Continents from Space with Synthetic Aperture Radar (LiCSAR), an operational system built for large-scale interferometric processing of Sentinel-1 data. LiCSAR is designed to automatically produce geocoded wrapped and unwrapped interferograms and coherence estimates, for large regions, at 0.001° resolution (WGS-84 coordinate system). The products are continuously updated at a frequency depending on prioritised regions (monthly, weekly or live update strategy). The products are open and freely accessible and downloadable through an online portal. We describe the algorithms, processing, and storage solutions implemented in LiCSAR, and show several case studies that use LiCSAR products to measure tectonic and volcanic deformation. We aim to accelerate the uptake of InSAR data by researchers as well as non-expert users by mass producing interferograms and derived products.

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