Compressed SAR Interferometry in the Big Data Era

Modern Synthetic Aperture Radar (SAR) missions provide an unprecedented massive interferometric SAR (InSAR) time series. The processing of the Big InSAR Data is challenging for long-term monitoring. Indeed, as most deformation phenomena develop slowly, a strategy of a processing scheme can be worked on reduced volume data sets. This paper introduces a novel ComSAR algorithm based on a compression technique for reducing computational efforts while maintaining the performance robustly. The algorithm divides the massive data into many mini-stacks and then compresses them. The compressed estimator is close to the theoretical Cramer–Rao lower bound under a realistic C-band Sentinel-1 decorrelation scenario. Both persistent and distributed scatterers (PSDS) are exploited in the ComSAR algorithm. The ComSAR performance is validated via simulation and application to Sentinel-1 data to map land subsidence of the salt mine Vauvert area, France. The proposed ComSAR yields consistently better performance when compared with the state-of-the-art PSDS technique. We make our PSDS and ComSAR algorithms as an open-source TomoSAR package. To make it more practical, we exploit other open-source projects so that people can apply our PSDS and ComSAR methods for an end-to-end processing chain. To our knowledge, TomoSAR is the first public domain tool available to jointly handle PS and DS targets.

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A least-squares approach for long-term monitoring of deformations with differential SAR interferometry

IEEE International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.2002.1025903 ◽

2003 ◽

Cited By ~ 4

Author(s):

S. Usai

Keyword(s):

Least Squares ◽

Sar Interferometry ◽

Long Term Monitoring ◽

Differential Sar Interferometry ◽

Term Monitoring ◽

Least Squares Approach

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Changes Over Time

Freshwater Ecology and Conservation ◽

10.1093/oso/9780198766384.003.0013 ◽

2018 ◽

pp. 283-305 ◽

Cited By ~ 1

Author(s):

Peter A. Gell ◽

Marie-Elodie Perga ◽

C. Max Finlayson

Keyword(s):

Data Sets ◽

Lake Ecosystems ◽

Wetland Ecosystems ◽

Sediment Layers ◽

Time Frames ◽

Changes Over Time ◽

The Impact ◽

Term Monitoring ◽

Term Data

Freshwater systems are continuously shaped by cyclical and directional forces of change, whether they be natural or anthropogenic. Beyond gradual transitions disturbances can reset their internal dynamics generating an abrupt ecological shift. Long-term data sets of gradual or abrupt change can be accessed by exhuming the physical, chemical, and biological remains archived in the sediment layers within lakes and wetlands. Long-term monitoring programmes offer more detailed evidence, usually over shorter time frames. In combination these records attest to the response of wetlands to climate and the impact of industrialised people. Humans have modified lake ecosystems for millennia and the condition of many wetland ecosystems have changed such that they are now regarded as novel. Long-term records provide targets for wetland restoration and can identify the main drivers of degradation. Identification of the character of modern Ramsar wetlands may be enhanced by reference to records of past state.

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LiCSBAS: An Open-Source InSAR Time Series Analysis Package Integrated with the LiCSAR Automated Sentinel-1 InSAR Processor

Remote Sensing ◽

10.3390/rs12030424 ◽

2020 ◽

Vol 12 (3) ◽

pp. 424 ◽

Cited By ~ 23

Author(s):

Yu Morishita ◽

Milan Lazecky ◽

Tim Wright ◽

Jonathan Weiss ◽

John Elliott ◽

...

Keyword(s):

Time Series ◽

Time Series Analysis ◽

Open Source ◽

Large Scale ◽

Surface Deformation ◽

Atmospheric Correction ◽

Sar Interferometry ◽

Processing Scheme ◽

Series Analysis ◽

Analysis Package

For the past five years, the 2-satellite Sentinel-1 constellation has provided abundant and useful Synthetic Aperture Radar (SAR) data, which have the potential to reveal global ground surface deformation at high spatial and temporal resolutions. However, for most users, fully exploiting the large amount of associated data is challenging, especially over wide areas. To help address this challenge, we have developed LiCSBAS, an open-source SAR interferometry (InSAR) time series analysis package that integrates with the automated Sentinel-1 InSAR processor (LiCSAR). LiCSBAS utilizes freely available LiCSAR products, and users can save processing time and disk space while obtaining the results of InSAR time series analysis. In the LiCSBAS processing scheme, interferograms with many unwrapping errors are automatically identified by loop closure and removed. Reliable time series and velocities are derived with the aid of masking using several noise indices. The easy implementation of atmospheric corrections to reduce noise is achieved with the Generic Atmospheric Correction Online Service for InSAR (GACOS). Using case studies in southern Tohoku and the Echigo Plain, Japan, we demonstrate that LiCSBAS applied to LiCSAR products can detect both large-scale (>100 km) and localized (~km) relative displacements with an accuracy of <1 cm/epoch and ~2 mm/yr. We detect displacements with different temporal characteristics, including linear, periodic, and episodic, in Niigata, Ojiya, and Sanjo City, respectively. LiCSBAS and LiCSAR products facilitate greater exploitation of globally available and abundant SAR datasets and enhance their applications for scientific research and societal benefit.

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USB Flash Disk Recorder Based on STM32

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.591-593.1367 ◽

2012 ◽

Vol 591-593 ◽

pp. 1367-1370

Author(s):

Guang Yu Ou ◽

Xing Pan ◽

Yong Pan ◽

Yi Gao

Keyword(s):

Data Storage ◽

Sensor Technology ◽

Massive Data ◽

Accelerometer Sensor ◽

Storage Media ◽

New Type ◽

Long Term Monitoring ◽

Storage Demand ◽

Term Monitoring

USB flash disk recorder is a new type paperless data recorder, which gathers the USB flash disk technology, micro-processing technology, and digital sensor technology together, taking the lead in applying USB flash disk technology. Massive data storage demand is met by adopting FatFS file system to manage storage media. The entire data will be stored in the form of file so that it is convenient for data storage and transmission. Moreover, the system concerned with the bad block management problems in NandFlash will be optimized and thus the reliability of the system will also improve. System test is performed by the accelerometer sensor. It is able to make long-term monitoring on the shock intensity and record the shock peak and waveform.

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Total Ozone Dobson, Brewer, Saoz and satellites comparisons at the historical station Arosa

10.5194/amt-2019-211 ◽

2019 ◽

Author(s):

Jean-Pierre Pommereau ◽

Florence Goutail ◽

René Stübi ◽

Geir Braathen

Keyword(s):

Cross Sections ◽

Total Ozone ◽

Ultra Violet ◽

Atmospheric Composition ◽

Data Sets ◽

Ozone Profile ◽

Mass Factor ◽

Ozone Column ◽

Term Monitoring

Abstract. Given the importance of the long-term monitoring of the evolution of ozone and following the frequent disruptions of satellites operations, the understanding of quality and stability of ground-based instruments measurements (Dobson, Brewer, SAOZ) performing over several decades, is essential. This is not only for their own records, but also for evaluating the performance of satellites systems and the reprocessing of their data. Many data sets inter-comparisons between Dobson/Brewer networks and satellites are already available (e.g. Redondas et al. 2014 and references therein), for the 40 years of SBUV (Labow et al. 2013) or for the OMI AURA (Balis et al., 2007; McPeters et al. 2008). Here, we evaluate the performance of SAOZ Total Ozone Column (TOC) measurements carried out in Arosa between October 2015 and March 2017 by comparison to simultaneous Dobson, Brewer and satellites observations available there. On average, when using Serdyuchenko et al. (2014) ozone cross-sections for all measurements and correcting the Dobson for its temperature dependence, Dobson, Brewer and SAOZ agree within 1 %, providing confidence to the long-term SAOZ measurements carried out all over the world within the international Network for the Detection of Atmospheric Composition Change (NDACC). However, the differences between SAOZ and Dobson/Brewer do show a small seasonality of the order of 1–2 % generated by the use of a zonal mean TOMS v8 profile climatology in the SAOZ air mass factor (AMF) calculation, not taking into account seasonal variations. On the satellites side, the differences with ground based TOCs show larger and highly variable biases (between −1.2 % and +2.4 %) as well as larger seasonality (around 2–3 %) on all satellites, except remarkably with the Solar Backscatter Ultra Violet instrument (SBUV) for which the bias is smaller than 0.4% and the seasonality less than 1 %. Asides from ozone absorption cross-sections, most important for satellites TOCs differences are the satellites measurements techniques: ozone profiles for SBUV, in contrast to all other nadir viewing satellites, sensitive like SAOZ, to ozone profile shape assumption.

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Comparing and Integrating Fish Surveys in the San Francisco Estuary: Why Diverse Long-Term Monitoring Programs are Important

San Francisco Estuary and Watershed Science ◽

10.15447/sfews.2020v18iss2art4 ◽

2020 ◽

Vol 18 (2) ◽

Author(s):

Dylan Stompe ◽

Peter Moyle ◽

Avery Kruger ◽

John Durand

Keyword(s):

Survey Data ◽

San Francisco ◽

Monitoring Program ◽

San Francisco Estuary ◽

Data Sets ◽

Data Set ◽

Monitoring Programs ◽

Long Term Monitoring ◽

Term Monitoring

Many fishes in the San Francisco Estuary have suffered declines in recent decades, as shown by numerous long-term monitoring programs. A long-term monitoring program, such as the Interagency Ecological Program, comprises a suite of surveys, each conducted by a state or federal agency or academic institution. These types of programs have produced rich data sets that are useful for tracking species trends over time. Problems arise from drawing conclusions based on one or few surveys because each survey samples a different subset of species or reflects different spatial or temporal trends in abundance. The challenges in using data sets from these surveys for comparative purposes stem from methodological differences, magnitude of data, incompatible data formats, and end-user preference for familiar surveys. To improve the utility of these data sets and encourage multi-survey analyses, we quantitatively rate these surveys based on their ability to represent species trends, present a methodology for integrating long-term data sets, and provide examples that highlight the importance of expanded analyses. We identify areas and species that are under-sampled, and compare fish salvage data from large water export facilities with survey data. Our analysis indicates that while surveys are redundant for some species, no two surveys are completely duplicative. Differing trends become evident when considering individual and aggregate survey data, because they imply spatial, seasonal, or gear-dependent catch. Our quantitative ratings and integrated data set allow for improved and better-informed comparisons of species trends across surveys, while highlighting the importance of the current array of sampling methodologies.

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