Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes
The recent changes of outlet glaciers flow speed have vast control of the undergoing mass loss of the Greenland ice sheet. The processes driving the flow variability on different time scales, as well as the associated consequences and feedbacks, are not yet entirely understood. This is partly becaus...
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ftunigrenoble:oai:HAL:tel-03508093v1 2024-05-12T08:04:00+00:00 Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes Variabilité saisonnière de l'écoulement des glaciers groenlandais : observations par satellite et modélisation numérique pour étudier les processus moteurs Derkacheva, Anna Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) Université Grenoble Alpes 2020-. Jérémie Mouginot 2021-09-23 https://theses.hal.science/tel-03508093 https://theses.hal.science/tel-03508093/document https://theses.hal.science/tel-03508093/file/DERKACHEVA_2021_archivage.pdf en eng HAL CCSD NNT: 2021GRALU024 tel-03508093 https://theses.hal.science/tel-03508093 https://theses.hal.science/tel-03508093/document https://theses.hal.science/tel-03508093/file/DERKACHEVA_2021_archivage.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-03508093 Global Changes. Université Grenoble Alpes [2020-.], 2021. English. ⟨NNT : 2021GRALU024⟩ Remote sensing Seasonal variations Physical processes Glacier Greenland Télédétection Variations saisonnières Processus physiques Groenland [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/doctoralThesis Theses 2021 ftunigrenoble 2024-04-18T03:10:41Z The recent changes of outlet glaciers flow speed have vast control of the undergoing mass loss of the Greenland ice sheet. The processes driving the flow variability on different time scales, as well as the associated consequences and feedbacks, are not yet entirely understood. This is partly because the lack of frequent, precise, and large-scale observations limits the development of the numerical models. It is particularly difficult to resolve seasonal speed fluctuations, yet it is crucial to better constrain the physical processes controlling the ice flow.This thesis aims to address (i) the difficulties that exist in establishing robust seasonal time-series of Greenland glacier surface velocities from satellite observations, and (ii) the use of these time-series in numerical models for better understanding of the flow drivers.Satellites are able to cover large areas in a relatively short time and uniform way. Continuous time-series with seasonal temporal resolution have only started to be used recently, due to the limited number of image acquisitions made previously. Nevertheless, the time-series of ice surface velocity derived from individual sensors remain temporally incomplete and relatively noisy. Taking together three suitable satellites (Landsat-8, Sentinel-2, and Sentinel-1) across three case study sites in Greenland (Russell sector, Upernavik Isstrøm and Petermann Gletscher), we demonstrate that it is possible to obtain continuous year-around time-series only by combining results from multiple satellites. It is also shown here that by applying post-processing based on the data redundancy to such multi-sensor datasets, we are able to achieve persistent tracking of ice surface motion with a temporal resolution of about 2 weeks and mean accuracy of about 10 m/yr. With such parameters, we can resolve the seasonal variability of greenlandic glaciers where previous studies had limited success.Elaboration of reliable numerical models which would correctly represent the ice flow processes requires suitable ... Doctoral or Postdoctoral Thesis glacier Greenland greenlandic Groenland groenlandais Ice Sheet Petermann gletscher Upernavik Université Grenoble Alpes: HAL Greenland Petermann Gletscher ENVELOPE(-59.500,-59.500,80.500,80.500) Upernavik Isstrøm ENVELOPE(-54.500,-54.500,72.917,72.917) |
institution |
Open Polar |
collection |
Université Grenoble Alpes: HAL |
op_collection_id |
ftunigrenoble |
language |
English |
topic |
Remote sensing Seasonal variations Physical processes Glacier Greenland Télédétection Variations saisonnières Processus physiques Groenland [SDE.MCG]Environmental Sciences/Global Changes |
spellingShingle |
Remote sensing Seasonal variations Physical processes Glacier Greenland Télédétection Variations saisonnières Processus physiques Groenland [SDE.MCG]Environmental Sciences/Global Changes Derkacheva, Anna Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
topic_facet |
Remote sensing Seasonal variations Physical processes Glacier Greenland Télédétection Variations saisonnières Processus physiques Groenland [SDE.MCG]Environmental Sciences/Global Changes |
description |
The recent changes of outlet glaciers flow speed have vast control of the undergoing mass loss of the Greenland ice sheet. The processes driving the flow variability on different time scales, as well as the associated consequences and feedbacks, are not yet entirely understood. This is partly because the lack of frequent, precise, and large-scale observations limits the development of the numerical models. It is particularly difficult to resolve seasonal speed fluctuations, yet it is crucial to better constrain the physical processes controlling the ice flow.This thesis aims to address (i) the difficulties that exist in establishing robust seasonal time-series of Greenland glacier surface velocities from satellite observations, and (ii) the use of these time-series in numerical models for better understanding of the flow drivers.Satellites are able to cover large areas in a relatively short time and uniform way. Continuous time-series with seasonal temporal resolution have only started to be used recently, due to the limited number of image acquisitions made previously. Nevertheless, the time-series of ice surface velocity derived from individual sensors remain temporally incomplete and relatively noisy. Taking together three suitable satellites (Landsat-8, Sentinel-2, and Sentinel-1) across three case study sites in Greenland (Russell sector, Upernavik Isstrøm and Petermann Gletscher), we demonstrate that it is possible to obtain continuous year-around time-series only by combining results from multiple satellites. It is also shown here that by applying post-processing based on the data redundancy to such multi-sensor datasets, we are able to achieve persistent tracking of ice surface motion with a temporal resolution of about 2 weeks and mean accuracy of about 10 m/yr. With such parameters, we can resolve the seasonal variability of greenlandic glaciers where previous studies had limited success.Elaboration of reliable numerical models which would correctly represent the ice flow processes requires suitable ... |
author2 |
Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) Université Grenoble Alpes 2020-. Jérémie Mouginot |
format |
Doctoral or Postdoctoral Thesis |
author |
Derkacheva, Anna |
author_facet |
Derkacheva, Anna |
author_sort |
Derkacheva, Anna |
title |
Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
title_short |
Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
title_full |
Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
title_fullStr |
Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
title_full_unstemmed |
Seasonal flow variability of Greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
title_sort |
seasonal flow variability of greenlandic glaciers : satellite observations and numerical modeling to study driving processes |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://theses.hal.science/tel-03508093 https://theses.hal.science/tel-03508093/document https://theses.hal.science/tel-03508093/file/DERKACHEVA_2021_archivage.pdf |
long_lat |
ENVELOPE(-59.500,-59.500,80.500,80.500) ENVELOPE(-54.500,-54.500,72.917,72.917) |
geographic |
Greenland Petermann Gletscher Upernavik Isstrøm |
geographic_facet |
Greenland Petermann Gletscher Upernavik Isstrøm |
genre |
glacier Greenland greenlandic Groenland groenlandais Ice Sheet Petermann gletscher Upernavik |
genre_facet |
glacier Greenland greenlandic Groenland groenlandais Ice Sheet Petermann gletscher Upernavik |
op_source |
https://theses.hal.science/tel-03508093 Global Changes. Université Grenoble Alpes [2020-.], 2021. English. ⟨NNT : 2021GRALU024⟩ |
op_relation |
NNT: 2021GRALU024 tel-03508093 https://theses.hal.science/tel-03508093 https://theses.hal.science/tel-03508093/document https://theses.hal.science/tel-03508093/file/DERKACHEVA_2021_archivage.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1798846133092483072 |