Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques
This thesis examines the utility of the Rényi entropy (RE), a measure of the complexity of probability density functions, as a tool for finding physically meaningful patterns in geophysical data. Initially, the RE is applied to observational data of long-lived atmospheric tracers in order to analyse...
Main Author: | |
---|---|
Format: | Other/Unknown Material |
Language: | English |
Published: |
University of Canterbury. Physics & Astronomy
2013
|
Subjects: | |
Online Access: | http://hdl.handle.net/10092/8534 https://doi.org/10.26021/7595 |
id |
ftunivcanter:oai:ir.canterbury.ac.nz:10092/8534 |
---|---|
record_format |
openpolar |
spelling |
ftunivcanter:oai:ir.canterbury.ac.nz:10092/8534 2023-05-15T13:49:25+02:00 Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques Krützmann, Nikolai Christian 2013 application/pdf zip http://hdl.handle.net/10092/8534 https://doi.org/10.26021/7595 en eng University of Canterbury. Physics & Astronomy NZCU http://hdl.handle.net/10092/8534 http://dx.doi.org/10.26021/7595 Copyright Nikolai Christian Kruetzmann https://canterbury.libguides.com/rights/theses Atmosphere cryosphere Antarctica snow compaction ice glacier McMurdo Ice Shelf GPR Ground Penetrating Radar deconvolution fourier deconvolution domain filling tropical pipe tropical leak RE Renyi entropy chaos theory complexity complexity measure stratosphere mixing Theses / Dissertations 2013 ftunivcanter https://doi.org/10.26021/7595 2022-09-08T13:36:18Z This thesis examines the utility of the Rényi entropy (RE), a measure of the complexity of probability density functions, as a tool for finding physically meaningful patterns in geophysical data. Initially, the RE is applied to observational data of long-lived atmospheric tracers in order to analyse the dynamics of stratospheric transitions regions associated with barriers to horizontal mixing. Its wider applicability is investigated by testing the RE as a method for highlighting internal boundaries in snow and ice from ground penetrating radar (GPR) recordings. High-resolution 500 MHz GPR soundings of dry snow were acquired at several sites near Scott Base, Antarctica, in 2008 and 2009, with the aim of using the RE to facilitate the identification and tracking of subsurface layers to extrapolate point measurements of accumulation from snow pits and firn cores to larger areas. The atmospheric analysis focuses on applying the RE to observational tracer data from the EOS-MLS satellite instrument. Nitrous oxide (N2O) is shown to exhibit subtropical RE maxima in both hemispheres. These peaks are a measure of the tracer gradients that mark the transition between the tropics and the mid-latitudes in the stratosphere, also referred to as the edges of the tropical pipe. The RE maxima are shown to be located closer to the equator in winter than in summer. This agrees well with the expected behaviour of the tropical pipe edges and is similar to results reported by other studies. Compared to other stratospheric mixing metrics, the RE has the advantage that it is easy to calculate as it does not, for example, require conversion to equivalent latitude and does not rely on dynamical information such as wind fields. The RE analysis also reveals occasional sudden poleward shifts of the southern hemisphere tropical pipe edge during austral winter which are accompanied by increased mid-latitude N2O levels. These events are investigated in more detail by creating daily high-resolution N2O maps using a two-dimensional trajectory ... Other/Unknown Material Antarc* Antarctica Ice Shelf McMurdo Ice Shelf University of Canterbury, Christchurch: UC Research Repository Austral McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Scott Base ENVELOPE(166.766,166.766,-77.849,-77.849) |
institution |
Open Polar |
collection |
University of Canterbury, Christchurch: UC Research Repository |
op_collection_id |
ftunivcanter |
language |
English |
topic |
Atmosphere cryosphere Antarctica snow compaction ice glacier McMurdo Ice Shelf GPR Ground Penetrating Radar deconvolution fourier deconvolution domain filling tropical pipe tropical leak RE Renyi entropy chaos theory complexity complexity measure stratosphere mixing |
spellingShingle |
Atmosphere cryosphere Antarctica snow compaction ice glacier McMurdo Ice Shelf GPR Ground Penetrating Radar deconvolution fourier deconvolution domain filling tropical pipe tropical leak RE Renyi entropy chaos theory complexity complexity measure stratosphere mixing Krützmann, Nikolai Christian Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques |
topic_facet |
Atmosphere cryosphere Antarctica snow compaction ice glacier McMurdo Ice Shelf GPR Ground Penetrating Radar deconvolution fourier deconvolution domain filling tropical pipe tropical leak RE Renyi entropy chaos theory complexity complexity measure stratosphere mixing |
description |
This thesis examines the utility of the Rényi entropy (RE), a measure of the complexity of probability density functions, as a tool for finding physically meaningful patterns in geophysical data. Initially, the RE is applied to observational data of long-lived atmospheric tracers in order to analyse the dynamics of stratospheric transitions regions associated with barriers to horizontal mixing. Its wider applicability is investigated by testing the RE as a method for highlighting internal boundaries in snow and ice from ground penetrating radar (GPR) recordings. High-resolution 500 MHz GPR soundings of dry snow were acquired at several sites near Scott Base, Antarctica, in 2008 and 2009, with the aim of using the RE to facilitate the identification and tracking of subsurface layers to extrapolate point measurements of accumulation from snow pits and firn cores to larger areas. The atmospheric analysis focuses on applying the RE to observational tracer data from the EOS-MLS satellite instrument. Nitrous oxide (N2O) is shown to exhibit subtropical RE maxima in both hemispheres. These peaks are a measure of the tracer gradients that mark the transition between the tropics and the mid-latitudes in the stratosphere, also referred to as the edges of the tropical pipe. The RE maxima are shown to be located closer to the equator in winter than in summer. This agrees well with the expected behaviour of the tropical pipe edges and is similar to results reported by other studies. Compared to other stratospheric mixing metrics, the RE has the advantage that it is easy to calculate as it does not, for example, require conversion to equivalent latitude and does not rely on dynamical information such as wind fields. The RE analysis also reveals occasional sudden poleward shifts of the southern hemisphere tropical pipe edge during austral winter which are accompanied by increased mid-latitude N2O levels. These events are investigated in more detail by creating daily high-resolution N2O maps using a two-dimensional trajectory ... |
format |
Other/Unknown Material |
author |
Krützmann, Nikolai Christian |
author_facet |
Krützmann, Nikolai Christian |
author_sort |
Krützmann, Nikolai Christian |
title |
Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques |
title_short |
Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques |
title_full |
Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques |
title_fullStr |
Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques |
title_full_unstemmed |
Analysis of Internal Boundaries and Transition Regions in Geophysical Systems with Advanced Processing Techniques |
title_sort |
analysis of internal boundaries and transition regions in geophysical systems with advanced processing techniques |
publisher |
University of Canterbury. Physics & Astronomy |
publishDate |
2013 |
url |
http://hdl.handle.net/10092/8534 https://doi.org/10.26021/7595 |
long_lat |
ENVELOPE(166.500,166.500,-78.000,-78.000) ENVELOPE(166.766,166.766,-77.849,-77.849) |
geographic |
Austral McMurdo Ice Shelf Scott Base |
geographic_facet |
Austral McMurdo Ice Shelf Scott Base |
genre |
Antarc* Antarctica Ice Shelf McMurdo Ice Shelf |
genre_facet |
Antarc* Antarctica Ice Shelf McMurdo Ice Shelf |
op_relation |
NZCU http://hdl.handle.net/10092/8534 http://dx.doi.org/10.26021/7595 |
op_rights |
Copyright Nikolai Christian Kruetzmann https://canterbury.libguides.com/rights/theses |
op_doi |
https://doi.org/10.26021/7595 |
_version_ |
1766251352022843392 |