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"MacLachlan, C."
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Seasonal winter forecasts and the stratosphere
We investigate seasonal forecasts of the winter North Atlantic Oscillation (NAO) and their relationship with the stratosphere. Climatological frequencies of sudden stratospheric warming (SSW) and strong polar vortex (SPV) events are well represented and the predicted risk of events varies between 25 and 90% from winter to winter, indicating predictability beyond the deterministic range. The risk of SSW and SPV events relates to predicted NAO as expected, with NAO shifts of −6.5 and +4.8 hPa in forecast members containing SSW and SPV events. Most striking of all is that forecast skill of the surface winter NAO vanishes from these hindcasts if members containing SSW events are excluded.
Journal Article
Multi-model assessment of the impact of soil moisture initialization on mid-latitude summer predictability
Land surface initial conditions have been recognized as a potential source of predictability in sub-seasonal to seasonal forecast systems, at least for near-surface air temperature prediction over the mid-latitude continents. Yet, few studies have systematically explored such an influence over a sufficient hindcast period and in a multi-model framework to produce a robust quantitative assessment. Here, a dedicated set of twin experiments has been carried out with boreal summer retrospective forecasts over the 1992–2010 period performed by five different global coupled ocean–atmosphere models. The impact of a realistic versus climatological soil moisture initialization is assessed in two regions with high potential previously identified as hotspots of land–atmosphere coupling, namely the North American Great Plains and South-Eastern Europe. Over the latter region, temperature predictions show a significant improvement, especially over the Balkans. Forecast systems better simulate the warmest summers if they follow pronounced dry initial anomalies. It is hypothesized that models manage to capture a positive feedback between high temperature and low soil moisture content prone to dominate over other processes during the warmest summers in this region. Over the Great Plains, however, improving the soil moisture initialization does not lead to any robust gain of forecast quality for near-surface temperature. It is suggested that models biases prevent the forecast systems from making the most of the improved initial conditions.
Journal Article
The GloSea4 Ensemble Prediction System for Seasonal Forecasting
Seasonal forecasting systems, and related systems for decadal prediction, are crucial in the development of adaptation strategies to climate change. However, despite important achievements in this area in the last 10 years, significant levels of skill are only generally found over regions strongly connected with the El Niño–Southern Oscillation. With the aim of improving the skill of regional climate predictions in tropical and extratropical regions from intraseasonal to interannual time scales, a new Met Office global seasonal forecasting system (GloSea4) has been developed. This new system has been designed to be flexible and easy to upgrade so it can be fully integrated within the Met Office model development infrastructure. Overall, the analysis here shows an improvement of GloSea4 when compared to its predecessor. However, there are exceptions, such as the increased model biases that contribute to degrade the skill of Niño-3.4 SST forecasts starting in November. Global ENSO teleconnections and Madden–Julian oscillation anomalies are well represented in GloSea4. Remote forcings of the North Atlantic Oscillation by ENSO and the quasi-biennial oscillation are captured albeit the anomalies are weaker than those found in observations. Hindcast length issues and their implications for seasonal forecasting are also discussed.
Journal Article
Difficult Conversations with Adam Smith
What can Adam Smith can teach us about the emotional terrain of difficult conversations, particularly those that touch on lived realities of injustice, oppression, and marginalization? In Part One of the Theory of Moral Sentiments, Adam Smith takes a few pages to dwell on the topic of interpersonal disagreement: more specifically, on how differently we feel about disagreements \"with regard to such indifferent objects as concern neither me nor my companion\" (TMS, 21) than we do when our own fortunes, feelings and even identity are bound up in the topic at hand. I argue that careful attention to Smiths discussion of disagreement reveals a set of norms for navigating uncomfortable terrain that avoid the pitfalls of so-called tone-policing and other contemporary approaches to civility.
Journal Article
Difficult Conversations with Adam Smith
What can Adam Smith can teach us about the emotional terrain of difficult conversations, particularly those that touch on lived realities of injustice, oppression, and marginalization? In Part One of the Theory of Moral Sentiments, Adam Smith takes a few pages to dwell on the topic of interpersonal disagreement: more specifically, on how differently we feel about disagreements “with regard to such indifferent objects as concern neither me nor my companion” (TMS, 21) than we do when our own fortunes, feelings and even identity are bound up in the topic at hand. I argue that careful attention to Smith’s discussion of disagreement reveals a set of norms for navigating uncomfortable terrain that avoid the pitfalls of so-called tone-policing and other contemporary approaches to civility.
Journal Article
The Enigma of Perception
How do we acquire knowledge through a sensory input from our environment? In The Enigma of Perception, D.L.C. Maclachlan revives the traditional causal representative theory of perception which dominated philosophical thinking for hundreds of years by revealing the important element of truth the theory contained. The traditional theory was not a complete explanation of perception, because it presupposed a causal system including both the physical objects and the subjective experiences. The pattern of inference from sensations to external objects, which lies at its heart, is nevertheless legitimate, because the assumptions on which it depends are generally recognized as true. The emerging enigma is how to explain this original knowledge of the world on which the traditional theory depends. The key idea is that sense experience is constructed as a response to sensory input - an act whose purpose is to represent a reality beyond the cognitive subject. The Enigma of Perception develops original ideas to explain this process in detail, with help from numerous philosophers from John Locke to David Chalmers.
eBook
Quantitative geomorphological analysis of drumlins in the peterborough drumlin field, ontario, canada
Drumlins are enigmatic subglacial landforms that have been interpreted to form by a number of processes, including incremental accumulation of till, erosion of previously deposited sediment, catastrophic meltwater floods, and sediment deformation. However, relatively little is known about the controls on drumlin formation, such as spatially variable glacial processes or substrate characteristics, and how these controls may be identified from variations in drumlin morphology within a single drumlin field. This paper explores a computational method that allows identification of drumlins and extraction of their morphological characteristics from existing topographic digital data for a portion of the eterborough drumlin field in ntario, anada. Spatial and non-spatial analysis of the form and distribution of drumlins across the study area identifies drumlin characteristics such as size, elongation ratio, symmetry and long axis orientation and shows that drumlins are not randomly distributed across the region and their form characteristics have distinct regional trends. Kernel density analysis is used to identify the regional trends in drumlin characteristics. Factors that appear to influence the form and distribution of drumlins in the study area include sediment thickness, length of time beneath the ice, ice velocity and direction of ice movement. The distribution of particularly well developed asymmetric and elongate drumlins coincides with the location of a broad bedrock low and is interpreted to identify the former location of a fast-flowing ice stream.
Journal Article
Between Culture and Curricula: Exploring Student and Faculty Experiences of Undergraduate Research and Inquiry
Undergraduate research and inquiry is a growing movement within the teaching and learning nexus, with many institutions developing their practices within this culture of education. This study aimed to identify the perceptions and experiences surrounding undergraduate research and inquiry among students and faculty at McMaster University in Ontario, Canada; assess the extent of research and inquiry in the design of undergraduate courses; and explore the facilitators and obstacles educators encounter when attempting to implement this educational approach. Although differences exist in student and faculty definitions of undergraduate research and inquiry, we found two principal models that characterize its structure and delivery—the scaffold model and bookend model. A third, the abstract model, does not employ the practice of inquiry. Despite numerous benefits unique to undergraduate research and inquiry education identified by stakeholders, notable barriers (such as funding, faculty buy-in, limited student experience, and inherent competition) hinder its progress. Overall, we found a diversity of undergraduate research and inquiry practices across the university, operating within varying cultures and comfort levels, which suggests unequal access for student learners.
Journal Article