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The UC Research Repository collects, stores and makes available original research from postgraduate students, researchers and academics based at the University of Canterbury.
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Recent Submissions
COVID-19 Pandemic and Political Change in New Zealand: Leadership, Public Opinion, and Party Politics
(2021) Tan, Alex; Vanvari N
The COVID-19 pandemic that began in early 2020 continues to wreak havoc on the world.
At the height of the pandemic in 2020, New Zealand is one of the few states that was able to
keep the pandemic at bay with relatively low infection and death rates. The exemplary nature
of New Zealand’s pandemic management propelled its young Prime Minister – Jacinda
Ardern – to global political fame and led to a convincing electoral victory in the October
2020 general election. Indeed, since the NZ’s adoption of the MMP in 1996, no political
party has ever won over 50% of the legislative seats in an election and coalition governments
have become the norm. Yet, the Ardern-led Labour Party managed to be the first party to
win an outright majority. In this paper, we examine the convergence of adept handling of the
COVID-19 pandemic, the role of public opinion, and the political leadership of Ardern and
her cabinet members in political change in New Zealand during these uncertain times.
Extended ozone depletion and reduced snow and ice cover—Consequences for Antarctic biota
(Wiley, 2024) Robinson , Sharon A.; Revell, Laura; Mackenzie , Roy; Ossola , Rachele
AbstractStratospheric ozone, which has been depleted in recent decades by the release of anthropogenic gases, is critical for shielding the biosphere against ultraviolet‐B (UV‐B) radiation. Although the ozone layer is expected to recover before the end of the 21st century, a hole over Antarctica continues to appear each year. Ozone depletion usually peaks between September and October, when fortunately, most Antarctic terrestrial vegetation and soil biota is frozen, dormant and protected under snow cover. Similarly, much marine life is protected by sea ice cover. The ozone hole used to close before the onset of Antarctic summer, meaning that most biota were not exposed to severe springtime UV‐B fluxes. However, in recent years, ozone depletion has persisted into December, which marks the beginning of austral summer. Early summertime ozone depletion is concerning: high incident UV‐B radiation coincident with snowmelt and emergence of vegetation will mean biota is more exposed. The start of summer is also peak breeding season for many animals, thus extreme UV‐B exposure (UV index up to 14) may come at a vulnerable time in their life cycle. Climate change, including changing wind patterns and strength, and particularly declining sea ice, are likely to compound UV‐B exposure of Antarctic organisms, through earlier ice and snowmelt, heatwaves and droughts. Antarctic field research conducted decades ago tended to study UV impacts in isolation and more research that considers multiple climate impacts, and the true magnitude and timing of current UV increases is needed.
Very Low Frequency Observations During an Active DC Injection Campaign that Simulated Geomagnetic Storm effects on High Voltage Transformers
(2023) Clilverd M; Cobbett N; Brundell J; Dalzell M; Lapthorn, Andrew; Hardie S; Agger P; Subritzky S; Beggan C; Huebert J; Eaton E; Rodger C
In January 2023, in collaboration with our industry partner Transpower Ltd (New Zealand’s national grid operator), a
campaign was undertaken to inject large currents into operating high voltage transformers. New Zealand’s high voltage
DC (HVDC) link was used to inject current directly into the ground at Haywards substation near Wellington, including
into several 216MVA 220 kV / 110 kV autotransformers. Six injection test periods occurred, each lasting 1-2 hours. The
peak current injected into the ground was about 621 A, spread across several transformers within the Haywards
substation.
The injection campaign was undertaken for New Zealand’s Endeavour programme “Solar Tsunamis: Space-Weather
Prediction and Risk Mitigation for New Zealand’s Energy Infrastructure”. The technique of substation monitoring using
nearby very low frequency (VLF) receivers has been previously reported by the lead author, based on observations of
the Halfway Bush substation (HWB) in Dunedin, New Zealand. Evidence of harmonic distortion through enhanced odd
and even 50 Hz harmonic amplitudes during geomagnetically induced current (GIC) events of up to 50 A, associated
with large geomagnetic storms in 2017 and 2018, have already been observed and analysed in detail. Typically,
enhancements in the amplitude of harmonics in the 100 Hz to 600 Hz range have been detected during GIC events. The
VLF observations from HWB are consistent with the idea that the local transformers radiate even harmonics of the 50 Hz
fundamental mains frequency due to half-cycle saturation driven by additive dc flux induced by GIC. During the Active
Injection campaign at Haywards Station, two identical VLF receiving systems were deployed around the substation.
Each VLF system comprised a set of orthogonal magnetic field loop aerials.
Preliminary results from the VLF harmonic data suggest that observed variations in amplitude in the 100 – 600 Hz
frequency range were correlated with temporal variations in the injected ground current, particularly after the current had
been applied for more than 20 minutes. Prior to that, a slow increase in harmonic distortion occurred, beginning at the
time of the injection onset. For injected substation earth currents ranging from 300 A – 600 A (about 20 A – 35 A for
individual autotransformers) even small variations of the order of 10’s of amps appeared to be well correlated with the
VLF amplitude variations of even order harmonics. In this study we present the VLF data during the injection events,
describing the responses observed from a large, complex substation experiencing geomagnetic storm-like effects.
Investigation of nonlocal granular fluidity models using nuclear magnetic resonance
(AIP Publishing, 2024) Clarke DA; Poata J; Galvosas P; Holland, Daniel
Nonlocal rheology models describe features in granular flows, such as scale dependence and flow below the yield point, that are not captured by local rheology models. It has been proposed that these features may be described by the transport of a property known as the granular fluidity. In this article, we studied an annular Couette shear cell of lobelia seeds using nuclear magnetic resonance to collect detailed measurements of the velocity distribution and volume fraction. These data were used to study nonlocal granular rheology models. We found that the nonlocal granular fluidity model was capable of accurately describing the decay in the velocity profile along the shear gradient direction. We also measured the dimensionless fluidity and validated the general form of the relation between this quantity and the volume fraction.
To the RescEU? Disaster Risk Management as a Driver for European Integration
(2024) Hopkins, W. John; Faulkner , Holly; Clausing , Silke
The European Union has incrementally expanded its role in the field of disaster risk management (DRM) since the late 1980s. This expansion has often been very slow as states have regularly challenged the EU’s growing role in an area traditionally seen as core member-state business. Nevertheless, the increasing inability of individual Member States to respond effectively to disasters led to the establishment of the Union Civil Protection Mechanism (UCPM) in 2001. The mechanism was significantly strengthened in 2019 with the establishment of the rescEU operational reserve and again in 2021 as a response to the COVID-19 pandemic. This article assesses the development of EU responsibilities in the field the DRM in the context of EU integration. In particular, it asks whether increased risk from natural hazards is creating a new driver towards European co-operation and integration. Will disasters, ironically, play a significant role in ‘rescEU’ing the Union?