title: Fluxes of Energy and Water Vapour from Grazed Pasture on a Mineral Soil in the Waikato

authors: Kuske, Tehani Janelle

subjects: eddy covariance

abstract: The eddy covariance (EC) technique was used to measure half hourly fluxes of energy and evaporation from 15 December 2007 to 30 November 2008 at the Scott Research Farm, located 7 km east of Hamilton. Many other supporting measurements of climate and soil variables were also made. The research addressed three objectives:
1. To examine the accuracy of the eddy covariance measurement technique.
2. Understand the surface partitioning of energy and water vapour on a diurnal to annual timescale.
3. Compare measurements of evaporation to methods of estimation.
Average energy balance closure at Scott Farm was deficient by 24%, comparable to published studies of up to 30%. Three lysimeter studies were carried out to help verify eddy covariance data. These resulted in the conclusions that; 1) lysimeter pots needed to be deeper to allow for vegetation rooting depths to be encompassed adequately; 2) forcing energy balance closure was not supported by two of the studies (summer and winter); 3) latent heat flux (λE) gap filling of night time EC data during winter over estimated values by about 10 W m-2; and 4) the spring lysimeter study verified eddy covariance measurements including the closure forcing method. Some uncertainty still exists as to the accuracy of both lysimeter and EC methods of evaporation measurement because both methods still have potential biases, however for the purpose of this study, it would appear data are sufficiently accurate to have confidence in results. Energy and water vapour fluxes varied on both a diurnal and seasonal timescale. Diurnally, fluxes were small or negative at night and were highest during the day, usually at solar noon. Seasonally, spring and summer had the highest energy and evaporation fluxes and winter rates were small but tended to exceed available energy supply. Evaporation was constrained by soil moisture availability during summer and by energy availability during winter. Estimated annual evaporation at Scott Farm was 755 mm, 72% of precipitation. Two evaporation models were compared to eddy covariance evaporation (EEC) measurements; the FAO56 Penman-Monteith model (Eo) and the Priestley-Taylor model (EPT). Both models over estimated evaporation during dry conditions and slightly under estimated during winter. The α coefficient that is applied to EPT was not constant and a seasonally adjusted value would be most appropriate. A crop coefficient of 1.13 is needed for Eo measurements during moist conditions. Eo began over estimating evaporation when soil moisture contents dropped below ~44%. A water stress adjustment was applied to both models which improved evaporation estimates, however early onset of drying was not able to be adjusted for. The adjusted Eo model is the most accurate overall, when compared to EEC.

text: Fluxes of Energy and Water Vapour from Grazed Pasture on a Mineral Soil in the Waikato The eddy covariance (EC) technique was used to measure half hourly fluxes of energy and evaporation from 15 December 2007 to 30 November 2008 at the Scott Research Farm, located 7 km east of Hamilton. Many other supporting measurements of climate and soil variables were also made. The research addressed three objectives:
1. To examine the accuracy of the eddy covariance measurement technique.
2. Understand the surface partitioning of energy and water vapour on a diurnal to annual timescale.
3. Compare measurements of evaporation to methods of estimation.
Average energy balance closure at Scott Farm was deficient by 24%, comparable to published studies of up to 30%. Three lysimeter studies were carried out to help verify eddy covariance data. These resulted in the conclusions that; 1) lysimeter pots needed to be deeper to allow for vegetation rooting depths to be encompassed adequately; 2) forcing energy balance closure was not supported by two of the studies (summer and winter); 3) latent heat flux (λE) gap filling of night time EC data during winter over estimated values by about 10 W m-2; and 4) the spring lysimeter study verified eddy covariance measurements including the closure forcing method. Some uncertainty still exists as to the accuracy of both lysimeter and EC methods of evaporation measurement because both methods still have potential biases, however for the purpose of this study, it would appear data are sufficiently accurate to have confidence in results. Energy and water vapour fluxes varied on both a diurnal and seasonal timescale. Diurnally, fluxes were small or negative at night and were highest during the day, usually at solar noon. Seasonally, spring and summer had the highest energy and evaporation fluxes and winter rates were small but tended to exceed available energy supply. Evaporation was constrained by soil moisture availability during summer and by energy availability during winter. Estimated annual evaporation at Scott Farm was 755 mm, 72% of precipitation. Two evaporation models were compared to eddy covariance evaporation (EEC) measurements; the FAO56 Penman-Monteith model (Eo) and the Priestley-Taylor model (EPT). Both models over estimated evaporation during dry conditions and slightly under estimated during winter. The α coefficient that is applied to EPT was not constant and a seasonally adjusted value would be most appropriate. A crop coefficient of 1.13 is needed for Eo measurements during moist conditions. Eo began over estimating evaporation when soil moisture contents dropped below ~44%. A water stress adjustment was applied to both models which improved evaporation estimates, however early onset of drying was not able to be adjusted for. The adjusted Eo model is the most accurate overall, when compared to EEC.

year: 2009

title: Postgraduate boundary crossings?

authors: White, Elizabeth Jayne

abstract: This Special Issue: Crossing Philosophical, Cultural and Geographic Boundaries in Educational Scholarship?: Postgraduate Experiences arose out of an invited panel of postgraduate speakers at the 42nd Philosophy of Education Society of Australasia Conference, held 7–10 December 2012 in Chiayi, Taiwan. The wider conference theme of “Crossing Boundaries” generated lively discussions about what such encounters and experiences might mean in the broader sphere of education; while the postgraduate speakers were invited to address their personal experience of boundaries during doctoral study. The central thrust of this invitation was to consider the extent to which such boundaries could (or should) be crossed through postgraduate experiences, and to gain a deeper appreciation of what this might mean for scholars who venture – physically and/or philosophically – outside of familiar terrain. The papers that comprise this issue provide associated cross-cultural, cross-country and cross-philosophical narratives, reflections and interrogations of their experiences in this regard. In doing so the authors provide a rich landscape through which to consider boundary crossing as an opportunity to expand on knowledge and/or to appreciate ones own position through encounters with ‘other’. Such crossings (or attempts to cross) presented significant challenges to these students, as they reveal in this issue. Their insights highlight the point that crossing philosophical, cultural and geographic boundaries is often a difficult relationship between all three, and, that there are costs involved. Such profoundly confronting experiences of crossing (or not crossing) are not necessarily bridges to be traversed as much as a means of confronting boundaries through which students might gain important insights – about themselves as persons of culture, scholars and members of a global society that is characterized by difference. This complex encounter – for all its pleasure and pain – is, evident through every paper in this issue, and sets the scene for important 21st century dialogues concerning diversity and difference in education.

text: Postgraduate boundary crossings? This Special Issue: Crossing Philosophical, Cultural and Geographic Boundaries in Educational Scholarship?: Postgraduate Experiences arose out of an invited panel of postgraduate speakers at the 42nd Philosophy of Education Society of Australasia Conference, held 7–10 December 2012 in Chiayi, Taiwan. The wider conference theme of “Crossing Boundaries” generated lively discussions about what such encounters and experiences might mean in the broader sphere of education; while the postgraduate speakers were invited to address their personal experience of boundaries during doctoral study. The central thrust of this invitation was to consider the extent to which such boundaries could (or should) be crossed through postgraduate experiences, and to gain a deeper appreciation of what this might mean for scholars who venture – physically and/or philosophically – outside of familiar terrain. The papers that comprise this issue provide associated cross-cultural, cross-country and cross-philosophical narratives, reflections and interrogations of their experiences in this regard. In doing so the authors provide a rich landscape through which to consider boundary crossing as an opportunity to expand on knowledge and/or to appreciate ones own position through encounters with ‘other’. Such crossings (or attempts to cross) presented significant challenges to these students, as they reveal in this issue. Their insights highlight the point that crossing philosophical, cultural and geographic boundaries is often a difficult relationship between all three, and, that there are costs involved. Such profoundly confronting experiences of crossing (or not crossing) are not necessarily bridges to be traversed as much as a means of confronting boundaries through which students might gain important insights – about themselves as persons of culture, scholars and members of a global society that is characterized by difference. This complex encounter – for all its pleasure and pain – is, evident through every paper in this issue, and sets the scene for important 21st century dialogues concerning diversity and difference in education.

year: 2014

title: Te Kōtiritiri, Te Kōtaratara

authors: Maxwell, Te Kahautu

abstract: Haka. Lyrics composed by Te Kahautu Maxwell. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (3mins)

Waiata ā Tira: Aroha
Whakaeke: Pinepine Te Kura, Hau Te Kura
Mōteatea: Te Ao o Te Pārerā
Waiata ā Ringa: E pā to reo, Te Matatini, Herewini Parata
Poi: E ia e ia
Haka: Te Kōtiritiri, Te Kōtaratara
Whakawātea: Ōranga Tōiti, tōnui kōrero

text: Te Kōtiritiri, Te Kōtaratara Haka. Lyrics composed by Te Kahautu Maxwell. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (3mins)

Waiata ā Tira: Aroha
Whakaeke: Pinepine Te Kura, Hau Te Kura
Mōteatea: Te Ao o Te Pārerā
Waiata ā Ringa: E pā to reo, Te Matatini, Herewini Parata
Poi: E ia e ia
Haka: Te Kōtiritiri, Te Kōtaratara
Whakawātea: Ōranga Tōiti, tōnui kōrero

year: 2023-02-22