title: Rip current dynamics on an embayed beach

authors: Gallop, Shari L.

subjects: rip currents

abstract: Rip currents are fast, narrow currents which traverse the surf-zone in the seaward direction. The most important effect of rip currents is that they can pose a deadly hazard to beach-users. Rip currents and their interaction with waves and underwater morphology are still poorly understood. This is often attributed to a lack of high quality long-term datasets. This shortcoming is due to the difficulty of sampling in the turbulent surf-zone. Past attempts to compare rip current behaviour (e.g. alongshore spacing) to waves have failed to show that they interact. 

In this thesis, an improved technique of locating rip channels in video imagery is presented. Previous studies to create computer algorithms to locate rips in video imagery have only looked at one alongshore transect which is averaged in the cross-shore direction, and there have been issues making the algorithms work in complicated cases. The method created in this thesis uses computer algorithms to locate light intensity minima across the entire expanse of the surf-zone in video imagery. This was applied to a dataset from Tairua Beach. The light intensity minima are sorted into distinct rip channels to create a dataset spanning 3.3 years from 1999 until April 2002. Using the high quality rip data output from the algorithms, rip channel morphological reconfiguration events were defined using a measure of change. Wave climate was compared to the timing of these reconfiguration events. It was found that mean wave energy averaged over ten days and wave event duration showed a better relationship to the reconfiguration events than immediate, instantaneous measures of significant wave height. 

Rip channel spatial scale (i.e. cross-shore extent) was found to be critical in determining how rip channels behave during high wave events. At Tairua Beach, it was not uncommon for the surf-zone to be wide on one half of the beach and narrow on the other. This 'dual' surf-zone can be attributed to wave shadowing by offshore islands under certain wave directions. Smaller rip channels on the narrow half of the beach changed rapidly whereas larger rips were stable during the same period. This situation shows the importance of both hydrodynamic-control and topographic-control of rips, where rips may respond directly to changes in the wave conditions or be stabilised by the pre-existing morphology respectively. There was also a tendency for rips to form and persist at the headlands of the beach. 

A conceptual model was created to demonstrate how rip channels of different spatial scales respond to changes in the wave conditions. Small rips relative to the wave energy are more likely than larger rips to evolve, and vice versa.

text: Rip current dynamics on an embayed beach Rip currents are fast, narrow currents which traverse the surf-zone in the seaward direction. The most important effect of rip currents is that they can pose a deadly hazard to beach-users. Rip currents and their interaction with waves and underwater morphology are still poorly understood. This is often attributed to a lack of high quality long-term datasets. This shortcoming is due to the difficulty of sampling in the turbulent surf-zone. Past attempts to compare rip current behaviour (e.g. alongshore spacing) to waves have failed to show that they interact. 

In this thesis, an improved technique of locating rip channels in video imagery is presented. Previous studies to create computer algorithms to locate rips in video imagery have only looked at one alongshore transect which is averaged in the cross-shore direction, and there have been issues making the algorithms work in complicated cases. The method created in this thesis uses computer algorithms to locate light intensity minima across the entire expanse of the surf-zone in video imagery. This was applied to a dataset from Tairua Beach. The light intensity minima are sorted into distinct rip channels to create a dataset spanning 3.3 years from 1999 until April 2002. Using the high quality rip data output from the algorithms, rip channel morphological reconfiguration events were defined using a measure of change. Wave climate was compared to the timing of these reconfiguration events. It was found that mean wave energy averaged over ten days and wave event duration showed a better relationship to the reconfiguration events than immediate, instantaneous measures of significant wave height. 

Rip channel spatial scale (i.e. cross-shore extent) was found to be critical in determining how rip channels behave during high wave events. At Tairua Beach, it was not uncommon for the surf-zone to be wide on one half of the beach and narrow on the other. This 'dual' surf-zone can be attributed to wave shadowing by offshore islands under certain wave directions. Smaller rip channels on the narrow half of the beach changed rapidly whereas larger rips were stable during the same period. This situation shows the importance of both hydrodynamic-control and topographic-control of rips, where rips may respond directly to changes in the wave conditions or be stabilised by the pre-existing morphology respectively. There was also a tendency for rips to form and persist at the headlands of the beach. 

A conceptual model was created to demonstrate how rip channels of different spatial scales respond to changes in the wave conditions. Small rips relative to the wave energy are more likely than larger rips to evolve, and vice versa.

year: 2009

title: Book review: The politics of language education: Individuals and institutions.

authors: Barnard, Roger

subjects: book review

abstract: This article reviews the book: “The politics of language education: Individuals and institutions”, edited by J.C. Alderson.

text: Book review: The politics of language education: Individuals and institutions. This article reviews the book: “The politics of language education: Individuals and institutions”, edited by J.C. Alderson.

year: 2010

title: How learning stories shape understandings of children’s learning identities in one community of practice: A narrative inquiry

authors: Sands, Lorraine May

subjects: Narrative inquiry

abstract: Mā te mahi, ka mōhio; mā te mōhio, ka mārama; mā te mārama, ka mātau; mā te mātau, ka ora.
From hard work comes knowledge; from that knowledge comes understanding; from that understanding comes strength; from that strength comes wellbeing and life.
This thesis is a listening, dialogic investigation into ways the community of learners at Greerton Early Learning Centre considers learning stories have affected their children’s learning identities—that is, how they view themselves as learners. Aotearoa New Zealand’s early childhood curriculum, Te Whāriki, focuses on responsive, reciprocal relationships wrapped around the uniqueness and mana of each child. Learning stories—a research-based sociocultural narrative assessment approach—have been used in Aotearoa New Zealand early learning settings for over two decades to capture children’s learning while honouring the intent of Te Whāriki to nurture children’s languages, cultures, and identities. In the current climate of privatisation and neoliberalism, however, the value of learning stories is increasingly contested. This study refutes such discourses and instead navigates the value of multiple ways of knowing, meaningfully embedded in the lived experiences of children in relational communities.

This study was embedded in a narrative inquiry paradigm that sees reality as a socially mediated construction contained within stories that are told and retold across times, social contexts, and places. The study aimed to understand and document how storying children’s lived experience makes a meaningful difference to ways children view themselves as learners. Six children, their families, and their teachers were invited to reengage with selected learning stories from the children’s learning portfolios and then to rethink and retell how these learning stories contributed to their views of children’s learning identities.

The study found that learning stories have powerful effects on the ways children see themselves and on the ways those around them see the children as learners. It was clear from the data that children’s learning identities are embedded in the complex social and cultural contexts that surround them. The teachers’ long-term whanaungatanga relationships with mokopuna and whānau enabled kaiako to write learning stories that connected meaningfully with children’s wider historical, social, and cultural contexts. Insights into children’s learning from the learning stories were actively taken up by the parents and shaped the ways they saw and interacted with their children as learners. Likewise, teachers listened to stories shared from home (whether in a written learning story form or simply in the course of conversations), and these contributed to the teachers’ understandings of the children as agentic learners within sociocultural contexts. The physical folders of learning stories offered children powerful ways to maintain connections and a sense of pride in their learning achievements, linked to the people and places that surrounded those achievements.

Learning stories also enabled children to review their learning growth over time, including times when they had set goals, been supported in pursuing those goals by those around them, and had their achievements and dispositions honoured through documentation as a learning story. The process of robust engagement with crafting and reviewing their own and their colleagues’ learning stories played an important role in teachers’ ongoing professional learning. Finally, it was clear that across the whole community of practice—spanning mokopuna, whānau, and kaiako—learning stories played an important role in developing and reinforcing a shared language of learning as well as a shared understanding of the importance of children’s dispositions and working theories as the most highly valued forms of learning.

Although centred in one community, this research stands on the shoulders of many and may have resonance and implications for those in broader contexts. At a time when the usefulness and appropriateness of learning stories are increasingly contested, this study provides an important demonstration of the power of thoughtfully written learning stories and the alignment of this assessment approach with the vision and values of Te Whāriki. Further, with limited past research looking at the intersection of learning stories and children’s learning identities, this study’s rich account of this interaction in one community of practice provides a valuable contribution to the literature.

text: How learning stories shape understandings of children’s learning identities in one community of practice: A narrative inquiry Mā te mahi, ka mōhio; mā te mōhio, ka mārama; mā te mārama, ka mātau; mā te mātau, ka ora.
From hard work comes knowledge; from that knowledge comes understanding; from that understanding comes strength; from that strength comes wellbeing and life.
This thesis is a listening, dialogic investigation into ways the community of learners at Greerton Early Learning Centre considers learning stories have affected their children’s learning identities—that is, how they view themselves as learners. Aotearoa New Zealand’s early childhood curriculum, Te Whāriki, focuses on responsive, reciprocal relationships wrapped around the uniqueness and mana of each child. Learning stories—a research-based sociocultural narrative assessment approach—have been used in Aotearoa New Zealand early learning settings for over two decades to capture children’s learning while honouring the intent of Te Whāriki to nurture children’s languages, cultures, and identities. In the current climate of privatisation and neoliberalism, however, the value of learning stories is increasingly contested. This study refutes such discourses and instead navigates the value of multiple ways of knowing, meaningfully embedded in the lived experiences of children in relational communities.

This study was embedded in a narrative inquiry paradigm that sees reality as a socially mediated construction contained within stories that are told and retold across times, social contexts, and places. The study aimed to understand and document how storying children’s lived experience makes a meaningful difference to ways children view themselves as learners. Six children, their families, and their teachers were invited to reengage with selected learning stories from the children’s learning portfolios and then to rethink and retell how these learning stories contributed to their views of children’s learning identities.

The study found that learning stories have powerful effects on the ways children see themselves and on the ways those around them see the children as learners. It was clear from the data that children’s learning identities are embedded in the complex social and cultural contexts that surround them. The teachers’ long-term whanaungatanga relationships with mokopuna and whānau enabled kaiako to write learning stories that connected meaningfully with children’s wider historical, social, and cultural contexts. Insights into children’s learning from the learning stories were actively taken up by the parents and shaped the ways they saw and interacted with their children as learners. Likewise, teachers listened to stories shared from home (whether in a written learning story form or simply in the course of conversations), and these contributed to the teachers’ understandings of the children as agentic learners within sociocultural contexts. The physical folders of learning stories offered children powerful ways to maintain connections and a sense of pride in their learning achievements, linked to the people and places that surrounded those achievements.

Learning stories also enabled children to review their learning growth over time, including times when they had set goals, been supported in pursuing those goals by those around them, and had their achievements and dispositions honoured through documentation as a learning story. The process of robust engagement with crafting and reviewing their own and their colleagues’ learning stories played an important role in teachers’ ongoing professional learning. Finally, it was clear that across the whole community of practice—spanning mokopuna, whānau, and kaiako—learning stories played an important role in developing and reinforcing a shared language of learning as well as a shared understanding of the importance of children’s dispositions and working theories as the most highly valued forms of learning.

Although centred in one community, this research stands on the shoulders of many and may have resonance and implications for those in broader contexts. At a time when the usefulness and appropriateness of learning stories are increasingly contested, this study provides an important demonstration of the power of thoughtfully written learning stories and the alignment of this assessment approach with the vision and values of Te Whāriki. Further, with limited past research looking at the intersection of learning stories and children’s learning identities, this study’s rich account of this interaction in one community of practice provides a valuable contribution to the literature.

year: 2022