title: Spatial and temporal changes in soil climate and active layer depth in the Ross Sea Region, Antarctica, 1999-2018

authors: Carshalton, Annette

subjects: Antarctica

abstract: The depth of seasonal thaw (the active layer depth) integrates a range of soil and atmospheric climate variables and has potential to provide a clear signal of a changing climate. Nine soil climate monitoring stations (SCS) were established between 1999 and 2012 and are currently operating in the Ross Sea Region of Antarctica. At each monitoring station soil temperature and moisture are measured at a range of depths down to 120 cm. Atmospheric variables measured include; air temperature, relative humidity, solar radiation, and windspeed and direction. Data validation has been carried out through the comparison of multiple sensors and has given confidence in the dataset. The objectives of this thesis were to; describe the active layer, assess the dataset for significant long-term trends, investigate the link between large scale climate systems and permafrost temperature, to test the model of Adlam et al. (2010), and develop a predictive model suitable for modelling all ice free areas in Antarctica.  
Active layer depth (ALD) showed marked between-year variation, and between the SCS establishment and 2018.  The mean ALD was 7.5 cm at Mt Fleming, 38 cm at the Wright Valley South Wall, 37 cm at the Wright Valley North Wall, 23 cm at Victoria Valley, 49 cm at the Wright Valley floor, 50 cm on the coast at Marble Point, 29 cm at Minna Bluff, 33 cm at Scott Base, and >90 cm at Granite Harbour. There were no significant trends of warming or cooling in either ALD or in temperature at top of the permafrost. Relationships between ALD and altitude (R²=0.71), and with latitude (R²= 0.66) were identified. 
Wavelet analysis showed that both global and regional climate systems were significant drivers of de-seasonalised permafrost temperature (p <0.05).  The Southern Annular Mode showed relationships at both annual and biannual timescales; the Southern Oscillation Index had a relationship at a two to three year timescale; and the Amundsen Sea Low had an annual signal and some between season signals with de-seasonalised permafrost temperature, at the Wright Valley Floor, Victoria Valley, Marble Point and at Mt Fleming.
Nineteen potential models were developed using stepwise analysis and compared to the previous work of Adlam et al. (2010). Model 8 (Adj R² = 0.75) accounted for more variation in the data than the Adlam et al. (2010) model (Adj R² = 0.69) and predicted the ALD within ±10 cm at the five low altitude sites, using mean summer air temperature, mean winter air temperature, altitude and mean summer surface temperature. Model 14 (Adj R² = 0.49) was developed using data from all eight SCS sites, and was able to predict the ALD at high altitude sites within < ±11 cm, and the low altitude sites within < ±20 cm. Model 14 did not capture the between year variation with detail.
Future testing of model 8 and 14 is recommended using data from other parts of Antarctica, and both models could also be used to explore the use of satellite remote sensed surface temperature data in predicting ALD.  The database comprises approximately 87,000,000 data points, collected from both soil and atmospheric sensors, and becomes more valuable with time as the record gets longer. This thesis did not use all the available data in the network, and further research is recommended. The SCS network provides a robust baseline to predict future change and understand how Antarctica is impacted by the changing global climate.

text: Spatial and temporal changes in soil climate and active layer depth in the Ross Sea Region, Antarctica, 1999-2018 The depth of seasonal thaw (the active layer depth) integrates a range of soil and atmospheric climate variables and has potential to provide a clear signal of a changing climate. Nine soil climate monitoring stations (SCS) were established between 1999 and 2012 and are currently operating in the Ross Sea Region of Antarctica. At each monitoring station soil temperature and moisture are measured at a range of depths down to 120 cm. Atmospheric variables measured include; air temperature, relative humidity, solar radiation, and windspeed and direction. Data validation has been carried out through the comparison of multiple sensors and has given confidence in the dataset. The objectives of this thesis were to; describe the active layer, assess the dataset for significant long-term trends, investigate the link between large scale climate systems and permafrost temperature, to test the model of Adlam et al. (2010), and develop a predictive model suitable for modelling all ice free areas in Antarctica.  
Active layer depth (ALD) showed marked between-year variation, and between the SCS establishment and 2018.  The mean ALD was 7.5 cm at Mt Fleming, 38 cm at the Wright Valley South Wall, 37 cm at the Wright Valley North Wall, 23 cm at Victoria Valley, 49 cm at the Wright Valley floor, 50 cm on the coast at Marble Point, 29 cm at Minna Bluff, 33 cm at Scott Base, and >90 cm at Granite Harbour. There were no significant trends of warming or cooling in either ALD or in temperature at top of the permafrost. Relationships between ALD and altitude (R²=0.71), and with latitude (R²= 0.66) were identified. 
Wavelet analysis showed that both global and regional climate systems were significant drivers of de-seasonalised permafrost temperature (p <0.05).  The Southern Annular Mode showed relationships at both annual and biannual timescales; the Southern Oscillation Index had a relationship at a two to three year timescale; and the Amundsen Sea Low had an annual signal and some between season signals with de-seasonalised permafrost temperature, at the Wright Valley Floor, Victoria Valley, Marble Point and at Mt Fleming.
Nineteen potential models were developed using stepwise analysis and compared to the previous work of Adlam et al. (2010). Model 8 (Adj R² = 0.75) accounted for more variation in the data than the Adlam et al. (2010) model (Adj R² = 0.69) and predicted the ALD within ±10 cm at the five low altitude sites, using mean summer air temperature, mean winter air temperature, altitude and mean summer surface temperature. Model 14 (Adj R² = 0.49) was developed using data from all eight SCS sites, and was able to predict the ALD at high altitude sites within < ±11 cm, and the low altitude sites within < ±20 cm. Model 14 did not capture the between year variation with detail.
Future testing of model 8 and 14 is recommended using data from other parts of Antarctica, and both models could also be used to explore the use of satellite remote sensed surface temperature data in predicting ALD.  The database comprises approximately 87,000,000 data points, collected from both soil and atmospheric sensors, and becomes more valuable with time as the record gets longer. This thesis did not use all the available data in the network, and further research is recommended. The SCS network provides a robust baseline to predict future change and understand how Antarctica is impacted by the changing global climate.

year: 2020

title: Application of new technology liquid scintillation spectrometry to radiocarbon dating of tephra deposits, New Zealand

authors: Lowe, David J.

abstract: Two major technological advances in the radiocarbon dating method have recently enhanced its potential application to tephra studies: the advent of accelerator mass spectrometry and the development of new technology liquid scintillation (LS) spectrometry. The new technology LS spectrometer represents a significant refinement of the conventional dating method based on liquid scintillation counting of benzene. It improves upon conventional LS counting by allowing spectral analysis, and by providing a high degree of counting stability and efficiency in an ultra low-level background radiation environment. These attributes enable radiocarbon dating with greater accuracy and statistical precision, and also allow the determination of both smaller and older samples than previously possible by conventional radiometric methods.
The new Wallac Oy ‘Quantulus’ LS spectrometer has been in operation at the University of Waikato Radiocarbon Dating Laboratory since 1988. The instrument achieves ultra-low background levels by both passive and active forms of shielding. The shielding comprises a massive asymmetric passive lead shield surrounding an aticoincident liquid scintillation guard. In addition, the Quantulus contains dual multichannel analyzers which allow spectral analysis and ‘windowless’ data acquisition.
The Quantulus LS spectrometers at the Waikato laboratory have been used to date a variety of carbonaceous materials associated with tephra deposits in New Zealand, ranging in age from ca. 0.1–55 ka. In particular, we have tested the capability of the Quantulus for determining ages of samples that are typically more difficult or impossible to date by conventional methods: (1) very young samples (e.g. Tarawera Tephra, erupted ca. 100 years ago); (2) older samples (e.g. Mangaone Tephra, erupted ca. 30 ka); and (3) samples containing only sparse carbon (e.g. lake sediments associated with tephra layers aged ca. 20 ka or less). The Quantulus LS spectrometer is both more accurate and precise (statistical counting errors are reduced) than conventional instruments, is capable of extending the limits of detection at both ends of the age scale, and has a smaller sample handling ability. Analyses can be obtained at comparatively low cost. Such advances are potentially beneficial to tephrochronology and volcanology and a wide range of applications in Quaternary research.

text: Application of new technology liquid scintillation spectrometry to radiocarbon dating of tephra deposits, New Zealand Two major technological advances in the radiocarbon dating method have recently enhanced its potential application to tephra studies: the advent of accelerator mass spectrometry and the development of new technology liquid scintillation (LS) spectrometry. The new technology LS spectrometer represents a significant refinement of the conventional dating method based on liquid scintillation counting of benzene. It improves upon conventional LS counting by allowing spectral analysis, and by providing a high degree of counting stability and efficiency in an ultra low-level background radiation environment. These attributes enable radiocarbon dating with greater accuracy and statistical precision, and also allow the determination of both smaller and older samples than previously possible by conventional radiometric methods.
The new Wallac Oy ‘Quantulus’ LS spectrometer has been in operation at the University of Waikato Radiocarbon Dating Laboratory since 1988. The instrument achieves ultra-low background levels by both passive and active forms of shielding. The shielding comprises a massive asymmetric passive lead shield surrounding an aticoincident liquid scintillation guard. In addition, the Quantulus contains dual multichannel analyzers which allow spectral analysis and ‘windowless’ data acquisition.
The Quantulus LS spectrometers at the Waikato laboratory have been used to date a variety of carbonaceous materials associated with tephra deposits in New Zealand, ranging in age from ca. 0.1–55 ka. In particular, we have tested the capability of the Quantulus for determining ages of samples that are typically more difficult or impossible to date by conventional methods: (1) very young samples (e.g. Tarawera Tephra, erupted ca. 100 years ago); (2) older samples (e.g. Mangaone Tephra, erupted ca. 30 ka); and (3) samples containing only sparse carbon (e.g. lake sediments associated with tephra layers aged ca. 20 ka or less). The Quantulus LS spectrometer is both more accurate and precise (statistical counting errors are reduced) than conventional instruments, is capable of extending the limits of detection at both ends of the age scale, and has a smaller sample handling ability. Analyses can be obtained at comparatively low cost. Such advances are potentially beneficial to tephrochronology and volcanology and a wide range of applications in Quaternary research.

year: 1992

title: Kua takoto te maanuka: Te tiimatanga o teetahi Kura Kaupapa Maaori

authors: Douglas, Vianney Gaye

subjects: Kura Kaupapa Maori

abstract: There is a paucity of literature on the establishment of new schools, and more particularly, the establishment of Kura Kaupapa Maaori. In addition, there is even less literature concerning the experiences and perspectives of whaanau and hapuu within Kaupapa Maaori initiatives. 

This thesis, therefore, illustrates the experience of a whaanau in the establishment of their Kura Kaupapa Maaori. The assertion within this thesis is that there are unique issues and challenges that Maaori communities encounter when pursuing the establishment of a Kura Kaupapa Maaori. Furthermore, a key factor in the success of establishing and sustaining the school is in the leadership.

Thus, the cognisance of Kaupapa Maaori and the development of Kura Kaupapa Maaori are explored. In addition, the key characteristics, roles and responsibilities of Maaori leadership both within the wider community and within schools are explored.

This case study included an interview with the Principal, and several focus group interviews with parents, staff and students of the new Kura Kaupapa who were involved with the school’s establishment during its first three years. In 2013, in its eleventh year, the school was identified as one of the top five successful Kura Kaupapa Maaori. 

The findings of this research will assist whaanau and leaders within schools to develop an understanding and appreciation of five key issues and challenges that a new school may face, and avenues that may take to address these.

text: Kua takoto te maanuka: Te tiimatanga o teetahi Kura Kaupapa Maaori There is a paucity of literature on the establishment of new schools, and more particularly, the establishment of Kura Kaupapa Maaori. In addition, there is even less literature concerning the experiences and perspectives of whaanau and hapuu within Kaupapa Maaori initiatives. 

This thesis, therefore, illustrates the experience of a whaanau in the establishment of their Kura Kaupapa Maaori. The assertion within this thesis is that there are unique issues and challenges that Maaori communities encounter when pursuing the establishment of a Kura Kaupapa Maaori. Furthermore, a key factor in the success of establishing and sustaining the school is in the leadership.

Thus, the cognisance of Kaupapa Maaori and the development of Kura Kaupapa Maaori are explored. In addition, the key characteristics, roles and responsibilities of Maaori leadership both within the wider community and within schools are explored.

This case study included an interview with the Principal, and several focus group interviews with parents, staff and students of the new Kura Kaupapa who were involved with the school’s establishment during its first three years. In 2013, in its eleventh year, the school was identified as one of the top five successful Kura Kaupapa Maaori. 

The findings of this research will assist whaanau and leaders within schools to develop an understanding and appreciation of five key issues and challenges that a new school may face, and avenues that may take to address these.

year: 2014