Advanced satellite radar interferometry for small-scale surface deformation detection

Synthetic aperture radar interferometry (InSAR) is a technique that enables generation of Digital Elevation Models (DEMs) and detection of surface motion at the centimetre level using radar signals transmitted from a satellite or an aeroplane. Deformation observations can be performed due to the fact that surface motion, caused by natural and human activities, generates a local phase shift in the resultant interferogram. The magnitude of surface deformation can be estimated directly as a fraction of the wavelength of the transmitted signal. Moreover, differential InSAR (DInSAR) eliminates the phase signal caused by relief to yield a differential interferogram in which the signature of surface deformation can be seen. Although InSAR applications are well established, the improvement of the interferometry technique and the quality of its products is highly desirable to further enhance its capabilities. The application of InSAR encounters problems due to noise in the interferometric phase measurement, caused by a number of decorrelation factors. In addition, the interferogram contains biases owing to satellite orbit errors and atmospheric heterogeneity These factors dramatically reduce the stlectiveness of radar interferometry in many applications, and, in particular, compromise detection and analysis of small-scale spatial deformations. The research presented in this thesis aim to apply radar interferometry processing to detect small-scale surface deformations, improve the quality of the interferometry products, determine the minimum and maximum detectable deformation gradient and enhance the analysis of the interferometric phase image. The quality of DEM and displacement maps can be improved by various methods at different processing levels. One of the methods is filtering of the interferometric phase.However, while filtering reduces noise in the interferogram, it does not necessarily enhance or recover the signal. Furthermore, the impact of the filter can significantly change the structure of the interferogram. A new adaptive radar interferogram filter has been developed and is presented herein. The filter is based on a modification to the Goldstein radar interferogram filter making the filter parameter dependent on coherence so that incoherent areas are filtered more than coherent areas. This modification minimises the loss of signal while still reducing the level of noise. A methodology leading to the creation of a functional model for determining minimum and maximum detectable deformation gradient, in terms of the coherence value, has been developed. The sets of representative deformation models have been simulated and the associated phase from these models has been introduced to real SAR data acquired by ERS-1/2 satellites. A number of cases of surface motion with varying magnitudes and spatial extent have been simulated. In each case, the resultant surface deformation has been compared with the 'true' surface deformation as defined by the deformation model. Based on those observations, the functional model has been developed. Finally, the extended analysis of the interferometric phase image using a wavelet approach is presented. The ability of a continuous wavelet transform to reveal the content of the wrapped phase interferogram, such as (i) discontinuities, (ii) extent of the deformation signal, and (iii) the magnitude of the deformation signal is examined. The results presented represent a preliminary study revealing the wavelet method as a promising technique for interferometric phase image analysis

Isotopic investigation of nitrates in Horyniec-Zdrój waters

In this work the isotopes of oxygen and nitrogen were determined in nitrates of water samples collected in Horyniec Zdrój and they allowed the preliminary indication of the source of NO3– ion. The obtained δ15N and δ18O values of nitrates dissolved in the Róża III therapeutic water are +2.1, +13.1 ‰, respectively. They indicate the origin of NO3- ion from bacterial decomposition of organic matter which is abundant in the aquifer.Interpretation of the processes affecting the chemical and isotopic composition of investigated waters was possible by taking into account earlier isotopic analyzes as well as chemical composition, geological structure and hydrogeological conditions prevailing in the aquifer. The results and discussion presented in this paper have excluded the possible influence of external contaminants in Horyniec-Zdrój waters used for therapeutic purposes

A new functional model for determining minimum and maximum detectable deformation gradient resolved by satellite radar interferometry

In this paper, a functional model for determining the minimum and maximum detectable deformation gradient in terms of coherence for synthetic aperture radar (SAR) sensors is presented. The model is developed based on a new methodology that incorporates both real and simulated data. Sets of representative surface deformation models have been simulated, and the associated phase from these models introduced into real SAR data acquired by European Remote Sensing 1 and 2 satellites. Subsequently,interferograms were derived, and surface deformation was estimated. A number of cases of surface deformation with varying magnitudes and spatial extent have been simulated. In each case, the resultant surface deformation has been compared with the "true" surface deformation as defined by the deformation model. Based on these comparisons, a set of observations that lead to a new functional model has been established.Finally, the proposed model has been validated against external datasets and proven viable. Although the major weakness of the model is its reliance on visual interpretation of interferograms, this model can serve as a decision-support tool to determine whether or not to apply satellite radar interferometry to study a given surface deformation

A modification to the Goldstein radar interferogram filter

We present a modification to the adaptive Goldsteinradar interferogram filter which improves the quality ofinterferometry products. The proposed approach makes theGoldstein filter parameter alpha dependent on coherence, suchthat incoherent areas are filtered more than coherent areas. Thismodification minimizes loss of signal while still reducing the levelof noise

A Modification to the Goldstein RadarInterferogram Filter

We present a modification to the adaptive Goldstein radar interferogram filter which improves the quality of interferometry products. The proposed approach makes the Goldstein filter parameter alpha dependent on coherence, suchthat incoherent areas are filtered more than coherent areas. This modification minimizes loss of signal while still reducing the level of noise

Rapid characterisation of vegetation structure to predict refugia and climate change impacts across a global biodiversity hotspot

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region.Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R2 of 0.8–0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia

Non-destructive testing of technical equipment using acoustic emission method

Technical devices operating in industrial conditions are subject to periodic technical inspection, in accordance with the Regulation of the Council of Ministers of 07 December 2012 on the types of technical devices subject to technical supervision (Journal of Laws 2012 item 1468). As part of periodic inspections, supplementary non-destructive testing (NDT) are carried out, such as: eddy current tests - ET, leak tests - LT, magnetic powder tests - MT, penetration tests - PT, ultrasonic tests - UT and visual tests - VT. The research program and scope of actions depends on many factors, including the type of device, material used, degradation mechanisms occurring, operating conditions of the device, or its operating time. Another NDT test method that is more and more widely used is the acoustic emission method (def. AE - acoustic emission, AT - acoustic emission testing according to PN-EN 1330-9: 2017-09). The ability to detect and locate AE signal sources, as well the ability to perform tests during the operation of devices (in-service), makes that this method is now worldwide considered as suitable for periodic testing of large objects, among others in the petrochemical and chemical. AT test allows detecting damages at an early stage of their occurrence, as well as at the same time allowing to globally monitoring whole object. The AT test complements very well together with other NDT methods, what allows verification and more accurate assessment of the detected damages. In many cases, the AE method is one of several methods used to assess the technical condition of the device. AT is used first of all at the initial stage, in order to indicate areas to tests by other NDT methods - for this reason this method is often called the "screening method". This article presents the basics of the AE method and its practical applications.Urządzenia techniczne pracujące w warunkach przemysłowych podlegają badaniom okresowym dozoru technicznego, zgodnie z Rozporządzeniem Rady Ministrów z dnia 07 grudnia 2012 r. w sprawie rodzajów urządzeń technicznych podlegających dozorowi technicznemu (Dz.U. 2012 poz. 1468). W ramach działań okresowych wykonywane są badania uzupełniające metodami nieniszczącymi (NDT), takimi jak: badania prądami wirowymi – ET, badania szczelności – LT, badania magnetyczno-proszkowe – MT, badania penetracyjne – PT, badania ultradźwiękowe – UT i badania wizualne – VT. Program badań i zakres czynności uzależniony jest od wielu czynników, w tym od rodzaju urządzenia, użytego materiału konstrukcyjnego, występujących mechanizmów degradacji, warunków pracy urządzenia czy też czasu jego eksploatacji. Inną metodą badań NDT, coraz szerzej stosowaną, jest metoda emisji akustycznej (def. AE – emisja akustyczna, AT – badanie emisją akustyczną wg PN-EN 1330-9:2017-09). Możliwość wykrywania i lokalizacji źródeł sygnałów AE oraz możliwość wykonania badań w trakcie eksploatacji urządzeń sprawia, że obecnie metoda ta jest na świecie uznawana za odpowiednią do badań okresowych dużych urządzeń, między innymi w przemyśle petrochemicznym i chemicznym. Badanie AT pozwala na ujawnienie uszkodzeń na wczesnym etapie ich występowania, a jednocześnie na objęcie badaniem całego obiektu. Badanie AT bardzo dobrze uzupełnia się z innymi metodami badań nieniszczących, co pozwala na weryfikację i dokładniejszą ocenę wykrywanych uszkodzeń. W wielu przypadkach metoda AE stanowi jedną z kilku wykorzystywanych metod do oceny stanu technicznego danego urządzenia. Stosuje się ją w pierwszej kolejności na etapie początkowym, w celu wskazania i uszczegółowienia miejsc do badania innymi metodami NDT – z tego powodu metoda ta często nazywana jest „metodą przesiewową”. W niniejszym artykule przedstawiono podstawy metody AE oraz jej praktyczne zastosowania

Investigation of the level of sludge inside a tank with the techniques AE and thermography

The article presents the techniques of AE and thermography to assess the level, volume and shape of sludge inside a storage tank. The thermographic method is used to assess the amount of sludge (height) along the tank's shell. In this case, the technique AE is used in a different way than usual. A special sensor system was used on the wall and roof of the tank. The sensors generate AE pulses in accordance with the established algorithm. The algorithm allows the recording of AE signals as a result of propagation and reflection of AE waves (including deposits) in the stored product between the sensors. Based on differences in the wave propagation time, sludge thickness is calculated at various points on the bottom of the tank.W artykule przedstawiono techniki AE i termografii do oceny poziomu, objętości i kształtu osadów w zbiorniku magazynowym. Metoda termograficzna służy do oceny poziomu osadu (wysokości) wzdłuż płaszcza zbiornika. Technika AE jest w tym przypadku wykorzystywana w inny sposób niż zwykle. Zastosowano specjalny układ czujników na ściance i dachu zbiornika. Czujniki generują impulsy AE zgodnie z ustalonym algorytmem, który pozwala na rejestrację sygnałów AE w wyniku propagacji fal i odbicia fal AE (w tym od osadów) w magazynowanym produkcie pomiędzy czujnikami. W oparciu o różnice w czasie propagacji fal są obliczane wysokości osadu w różnych punktach na dnie zbiornika

A Modification to the Goldstein Radar

We present a modification to the adaptive Goldstein radar interferogram filter which improves the quality of interferometry products. The proposed approach makes the Goldstein filter parameter alpha dependent on coherence, such that incoherent areas are filtered more than coherent areas. This modification minimizes loss of signal while still reducing the level of noise

Linear regression and leave-one-out (LOO) validation statistics of multiple linear regressions with parameter estimates of environmental factors determining maximum canopy height and ground coverage.

<p>The explanatory variables included annual rainfall (R, mm), probability of a soil deeper than 0.5 m (pDS), elevation range (EV, m) and their interactions, and granitic substrate. Insignificant terms (p<0.05) were excluded from the fitted models. Models evaluated were 1) all individual plots, 2) only on-flow plots, 3) geometric means for each plot type per outcrop and 4) geometric means of structural class polygon attributes covering at least 20% of plot areas.</p><p>Not significant;</p><p>p<0.05;</p><p>p<0.01;</p><p>Transect and elevation range were.</p