Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations
Space geodesy techniques (SAR interferometry and GNSS) have recently emerged as an important tool for mapping regional surface deformations due to tectonic movements. A limiting factor to this technique is the effect of the troposphere, as horizontal and vertical surface velocities are of the order...
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Μορφή: | Thesis |
Γλώσσα: | English |
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2020
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Διαθέσιμο Online: | http://hdl.handle.net/10889/13363 |
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GNSS Meteorology InSAR Troposheric noise WRF Remote sensing Δορυφορική μετεωρολογία Τροποσφαιρικός θόρυβος 526.6 |
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GNSS Meteorology InSAR Troposheric noise WRF Remote sensing Δορυφορική μετεωρολογία Τροποσφαιρικός θόρυβος 526.6 Ρουκουνάκης, Νικόλαος Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations |
description |
Space geodesy techniques (SAR interferometry and GNSS) have recently emerged as an important tool for mapping regional surface deformations due to tectonic movements. A limiting factor to this technique is the effect of the troposphere, as horizontal and vertical surface velocities are of the order of a few mm yr-1, and high accuracy (to mm level) is essential. The troposphere introduces a path delay in the microwave signal, which, in the case of GNSS Precise Point Positioning (PPP), can nowadays be successfully removed with the use of specialized mapping functions. Moreover, tropospheric stratification and short wavelength spatial turbulences produce an additive noise to the low amplitude ground deformations calculated by the (multitemporal) InSAR methodology. InSAR atmospheric phase delay corrections are much more challenging, as opposed to GNSS PPP, due to the single pass geometry and the gridded nature of the acquired data. Several methods have been proposed, including Global Navigation Satellite System (GNSS) zenithal delay estimations, satellite multispectral imagery analysis, and empirical phase/topography estimations. These methods have their limitations, as they rely either on local data assimilation, which is rarely available, or on empirical estimations which are difficult in situations where deformation and topography are correlated. Thus, the precise knowledge of the tropospheric parameters along the propagation medium is extremely useful for the estimation and minimization of atmospheric phase delay, so that the remaining signal represents the deformation mostly due to tectonic or other geophysical processes.
In this context, the current PhD Thesis aims to investigate the extent to which a high-resolution weather model, such as WRF, can produce detailed tropospheric delay maps of the required accuracy, by coupling its output (in terms of Zenith Total Delay or ZTD) with the vertical delay component in GNSS measurements. The model initially is operated with varying parameterization in order to demonstrate the best possible configuration for our study, with GNSS measurements providing a benchmark of real atmospheric conditions. In the next phase, the two datasets (predicted and observed) are compared and statistically evaluated for a period of one year, in order to investigate the extent to which meteorological parameters that affect ZTD, can be simulated accurately by the model under different weather conditions. Finally, a novel methodology is tested, in which ZTD maps produced from WRF and validated with GNSS measurements in the first phase of the experiment are used as a correction method to eliminate the tropospheric effect from selected InSAR interferograms. Results show that a high-resolution weather model which is fine-tuned at the local scale can provide a valuable tool for the tropospheric correction of InSAR remote sensing data. |
author2 |
Αργυρίου, Αθανάσιος |
author_facet |
Αργυρίου, Αθανάσιος Ρουκουνάκης, Νικόλαος |
format |
Thesis |
author |
Ρουκουνάκης, Νικόλαος |
author_sort |
Ρουκουνάκης, Νικόλαος |
title |
Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations |
title_short |
Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations |
title_full |
Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations |
title_fullStr |
Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations |
title_full_unstemmed |
Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations |
title_sort |
application of a high-resolution weather model in the area of the western gulf of corinth for the tropospheric correction of interferometric synthetic aperture radar (insar) observations |
publishDate |
2020 |
url |
http://hdl.handle.net/10889/13363 |
work_keys_str_mv |
AT roukounakēsnikolaos applicationofahighresolutionweathermodelintheareaofthewesterngulfofcorinthforthetroposphericcorrectionofinterferometricsyntheticapertureradarinsarobservations AT roukounakēsnikolaos troposphairikēdiorthōsēdedomenōndoryphorikēssymbolometriasinsarmetēnchrēsēmeteōrologikoumontelouypsēlēseukrineiasstēnperiochētoudytikoukorinthiakoukolpou |
_version_ |
1771297336678416384 |
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nemertes-10889-133632022-09-05T20:30:10Z Application of a high-resolution weather model in the area of the western Gulf of Corinth for the tropospheric correction of interferometric synthetic aperture radar (InSAR) observations Τροποσφαιρική διόρθωση δεδομένων δορυφορικής συμβολομετρίας InSAR με την χρήση μετεωρολογικού μοντέλου υψηλής ευκρίνειας στην περιοχή του δυτικού Κορινθιακού Κόλπου Ρουκουνάκης, Νικόλαος Αργυρίου, Αθανάσιος Briole, Pierre Κατσάμπαλος, Κωνσταντίνος Morel, Laurent Doubre, Cécile Lott, François Jacquemoud, Stéphane Roukounakis, Nikolaos GNSS Meteorology InSAR Troposheric noise WRF Remote sensing Δορυφορική μετεωρολογία Τροποσφαιρικός θόρυβος 526.6 Space geodesy techniques (SAR interferometry and GNSS) have recently emerged as an important tool for mapping regional surface deformations due to tectonic movements. A limiting factor to this technique is the effect of the troposphere, as horizontal and vertical surface velocities are of the order of a few mm yr-1, and high accuracy (to mm level) is essential. The troposphere introduces a path delay in the microwave signal, which, in the case of GNSS Precise Point Positioning (PPP), can nowadays be successfully removed with the use of specialized mapping functions. Moreover, tropospheric stratification and short wavelength spatial turbulences produce an additive noise to the low amplitude ground deformations calculated by the (multitemporal) InSAR methodology. InSAR atmospheric phase delay corrections are much more challenging, as opposed to GNSS PPP, due to the single pass geometry and the gridded nature of the acquired data. Several methods have been proposed, including Global Navigation Satellite System (GNSS) zenithal delay estimations, satellite multispectral imagery analysis, and empirical phase/topography estimations. These methods have their limitations, as they rely either on local data assimilation, which is rarely available, or on empirical estimations which are difficult in situations where deformation and topography are correlated. Thus, the precise knowledge of the tropospheric parameters along the propagation medium is extremely useful for the estimation and minimization of atmospheric phase delay, so that the remaining signal represents the deformation mostly due to tectonic or other geophysical processes. In this context, the current PhD Thesis aims to investigate the extent to which a high-resolution weather model, such as WRF, can produce detailed tropospheric delay maps of the required accuracy, by coupling its output (in terms of Zenith Total Delay or ZTD) with the vertical delay component in GNSS measurements. The model initially is operated with varying parameterization in order to demonstrate the best possible configuration for our study, with GNSS measurements providing a benchmark of real atmospheric conditions. In the next phase, the two datasets (predicted and observed) are compared and statistically evaluated for a period of one year, in order to investigate the extent to which meteorological parameters that affect ZTD, can be simulated accurately by the model under different weather conditions. Finally, a novel methodology is tested, in which ZTD maps produced from WRF and validated with GNSS measurements in the first phase of the experiment are used as a correction method to eliminate the tropospheric effect from selected InSAR interferograms. Results show that a high-resolution weather model which is fine-tuned at the local scale can provide a valuable tool for the tropospheric correction of InSAR remote sensing data. Αντικείμενο της διδακτορικής διατριβής είναι η ανάπτυξη μίας καινοτόμου μεθοδολογίας για την αφαίρεση της τροποσφαιρικής επίδρασης από εφαρμογές διαστημικής γεωδαισίας (GNSS και InSAR), οι οποίες αποτελούν σημαντικά εργαλεία για την παρακολούθηση περιβαλλοντικών παραμέτρων όπου απαιτείται υψηλή ακρίβεια ανίχνευσης (της τάξεως των χιλιοστών του μέτρου), όπως για παράδειγμα η μέτρηση επιφανειακών μετατοπίσεων του φλοιού της γης εξαιτίας τεκτονικών φαινομένων. Η τροπόσφαιρα εισαγάγει μια καθυστέρηση στο ηλεκτρομαγνητικό σήμα, η οποία διορθώνεται μερικώς (μόνο για τα GNSS), με την χρήση εξειδικευμένων τροποσφαιρικών μοντέλων. Επιπροσθέτως, η ατμοσφαιρική διαστρωμάτωση και οι έντονες χωροχρονικές διακυμάνσεις των υδρατμών μέσα σε αυτήν παράγουν ένα πρόσθετο «θόρυβο» στην παραμόρφωση του εδάφους που υπολογίζεται με την μεθοδολογία της συμβολομετρίας (InSAR). Επομένως, η γνώση των τροποσφαιρικών παραμέτρων κατά μήκος του μέσου διάδοσης μπορεί να χρησιμοποιηθεί για τον υπολογισμό και την ελαχιστοποίηση της επίδρασης του θορύβου αυτού, έτσι ώστε το εναπομένον σήμα να περιγράφει την παραμόρφωση, ως επί το πλείστον, λόγω τεκτονικών ή άλλων γεωφυσικών διεργασιών. Ο πρωταρχικός στόχος της διδακτορικής διατριβής είναι η σύζευξη της κατακόρυφης συνιστώσας των μετρήσεων GNSS υψηλής ακρίβειας (Precise Point Positioning), με τα δεδομένα εξόδου ενός μετεωρολογικού μοντέλου υψηλής ανάλυσης (WRF), ώστε να εξακριβωθεί η εγκυρότητα των αποτελεσμάτων και να παραμετροποιηθεί κατάλληλα το μοντέλο. Επιπλέον, η μελέτη επεκτείνεται στην διόρθωση της τροποσφαιρικής επίδρασης σε συμβολογραφήματα από περιοδικές λήψεις InSAR, κατά την ίδια περίοδο, για την περιοχή του Δυτικού Κορινθιακού Κόλπου. Κατ’ αυτόν τον τρόπο, η μεθοδολογία συνδυάζει σημειακές μετεωρολογικές παρατηρήσεις (GNSS) με τρισδιάστατα χωρικά μετεωρολογικά δεδομένα (WRF), για την παραγωγή αναλυτικών χαρτών ζενιθείας τροποσφαιρικής διόρθωσης (ZTD), που χρησιμοποιούνται για την αφαίρεση του θορύβου από τις απεικονίσεις InSAR. Τα αποτελέσματα αποδεικνύουν ότι ένα μετεωρολογικό μοντέλο υψηλής ευκρίνειας, με την κατάλληλη παραμετροποίηση, μπορεί να αποτελέσει πολύτιμο εργαλείο για την τροποσφαιρική διόρθωση δορυφορικών δεδομένων InSAR. 2020-03-25T19:46:13Z 2020-03-25T19:46:13Z 2019-10-23 Thesis http://hdl.handle.net/10889/13363 en 0 application/pdf |