Christopher Barrington-Leigh

Identification of sprites and elves with intensified video and broadband array photometry

Confusion in the interpretation of standard-speed video observations of optical flashes above intense cloud-to-ground lightning discharges has persisted for a number of years. New high-speed (3000 frames per second) image-intensified video recordings are used along with theoretical modeling to elucidate the optical signatures of elves and sprites. In particular, a brief diffuse flash sometimes observed to accompany or precede more structured sprites in standard-speed video is shown to be a normal component of sprite electrical breakdown and to be due entirely to the quasi-electrostatic thundercloud field (sprites), rather than the lightning electromagnetic pulse (elves). These “sprite halos” are expected to be produced by large charge moment changes occurring over relatively short timescales (∼1 ms), in accordance with their altitude extent of ∼70 to 85 km. The relatively short duration of this upper, diffuse component of sprites makes it difficult to detect and to discriminate from elves and Rayleigh-scattered light using normal-speed video systems. Modeled photometric array signatures of elves and sprites are contrasted and shown to be consistent with observations. Ionization in the diffuse portion of sprites may be a cause of VLF scattering phenomena known as early/fast VLF events.

Prosocial Spending and Well-Being : Cross-Cultural Evidence for a Psychological Universal

This research provides the first support for a possible psychological universal: Human beings around the world derive emotional benefits from using their financial resources to help others (prosocial spending). In Study 1, survey data from 136 countries were examined and showed that prosocial spending is associated with greater happiness around the world, in poor and rich countries alike. To test for causality, in Studies 2a and 2b, we used experimental methodology, demonstrating that recalling a past instance of prosocial spending has a causal impact on happiness across countries that differ greatly in terms of wealth (Canada, Uganda, and India). Finally, in Study 3, participants in Canada and South Africa randomly assigned to buy items for charity reported higher levels of positive affect than participants assigned to buy the same items for themselves, even when this prosocial spending did not provide an opportunity to build or strengthen social ties. Our findings suggest that the reward experienced from helping others may be deeply ingrained in human nature, emerging in diverse cultural and economic contexts.

Telescopic imaging of sprites

Telescopic images of sprites show a wide variety of generally vertical but also slanted fine structure, including branching tree-like shapes and well defined but isolated columns, with transverse spatial scales ranging from tens of meters to a few hundred meters at ∼60–85 km altitude. Simultaneous analysis of radio atmospheric and lightning data indicates that specific columnar regions are selectively excited by successive discharges.

ELF radiation produced by electrical currents in sprites

Measurements of ELF-radiating currents associated with sprite-producing lightning discharges exhibit a second current peak simultaneous in time with sprite luminosity, suggesting that the observed ELF radiation is produced by intense electrical currents flowing in the body of the sprite.

International Evidence on the Social Context of Well-Being

This paper uses the first three waves of the Gallup World Poll to investigate differences across countries, cultures and regions in the factors linked to life satisfaction, paying special attention to the social context. Our principal findings are: First, using the larger pooled sample, we find that answers to the satisfaction with life and Cantril ladder questions provide consistent views of what constitutes a good life, with an average of the two measures providing a clearer picture than either measure on its own. Second, we find strong evidence for the importance of both income and social context variables in explaining within-country and international differences in well-being. For most specifications tested, the combined effects of a few measures of the social and institutional context are as large as those of income in explaining both international and intra-national differences in life satisfaction. Third, the very significant influences of both income and social factors permit the calculation of compensating differentials for social factors. We find very large income-equivalent values for key measures of the social context. Fourth, the international similarity of the estimated equations suggests that the large international differences in average life evaluations are not due to different approaches to the meaning of a good life, but to differing social, institutional, and economic life circumstances.

Sprites triggered by negative lightning discharges

High altitude air breakdown, manifested as “red sprites,” is reported in close association with negative cloud-to-ground lightning (−CG) on at least two occasions above an unusual storm on August 29, 1998. Data from high speed photometry, low-light-level video, and receivers of lightning electromagnetic signatures in the frequency range 10 Hz to 20 kHz are used to establish the association and indicate that the causative −CG discharges effected unusually large vertical charge moment changes (ΔMQv) of up to 1550 C · km in 5 ms. The existence of sprites caused by −CGs, rather than the regularly associated +CGs, has immediate implications for sprite models and observations.

Elves triggered by positive and negative lightning discharges

Optical flashes in the lower ionosphere due to the transient heating caused by lightning electromagnetic pulses (EMP) are unambiguously identified with the Flys Eye photometric array. Data from a thunderstorm over Mexico recorded at Langmuir Laboratory on August 27 1997 demonstrate that relatively common negative cloud-to-ground lightning is a previously unrecognized major cause of elves. The spatial extent of the transient heating is shown optically to be typically at least 200–700 km laterally, indicating the possibility for accumulation of ionization effects produced by successive flashes within large nighttime thunderstorm systems. One especially bright event suggests that temporal fine-structure in the causative very low frequency EMP can manifest itself in the photometric record of elves.

Kernel regression for real-time building energy analysis

This study proposes a new technique for real-time building energy modelling and event detection using kernel regression. We show that this technique can exceed the performance of conventional neural network algorithms, and do so by a large margin when the available training dataset is small. Furthermore, unlike the synapse weights in a neural network, the parameters of our kernel regression models are amenable to human interpretation and can give useful information about the building being studied. We extensively test our proposed algorithms using a new dataset consisting of 1.5 years of power and environmental measurements for four buildings, in addition to benchmarking against the ASHRAE Predictor Shootout dataset. On the new dataset, our kernel regression algorithm gave the best prediction performance in three of four cases and significantly outperformed neural networks (the nearest competitor) with training sets of 1/2 a year or less.

A century of sprawl in the United States

Significance Urban development patterns in the 20th century have been increasingly typified by urban sprawl, which exacerbates climate change, energy and material consumption, and public health challenges. We construct the first long-run, high-resolution time series of street-network sprawl in the United States. We find that even in the absence of a coordinated policy effort, new developments have already turned the corner toward less sprawl. Initial impacts on vehicle travel and greenhouse gas emissions will be modest given that the stock of streets changes slowly, but feedbacks are likely to mean that benefits compound in future years. Our publicly released data provide further opportunities for research on urban development and the social and environmental impacts of different urban forms. The urban street network is one of the most permanent features of cities. Once laid down, the pattern of streets determines urban form and the level of sprawl for decades to come. We present a high-resolution time series of urban sprawl, as measured through street network connectivity, in the United States from 1920 to 2012. Sprawl started well before private car ownership was dominant and grew steadily until the mid-1990s. Over the last two decades, however, new streets have become significantly more connected and grid-like; the peak in street-network sprawl in the United States occurred in ∼1994. By one measure of connectivity, the mean nodal degree of intersections, sprawl fell by ∼9% between 1994 and 2012. We analyze spatial variation in these changes and demonstrate the persistence of sprawl. Places that were built with a low-connectivity street network tend to stay that way, even as the network expands. We also find suggestive evidence that local government policies impact sprawl, as the largest increases in connectivity have occurred in places with policies to promote gridded streets and similar New Urbanist design principles. We provide for public use a county-level version of our street-network sprawl dataset comprising a time series of nearly 100 y.

The Quebec Convergence and Canadian Life Satisfaction, 1985–2008

De plus en plus de sondages, réalisés par des gouvernements ou des entreprises privées, tentent de mesurer la satisfaction face à la vie, cette mesure étant obtenue grâce à des instruments d’auto-évaluation. Au Canada, de tels sondages n’ont pas été faits de façon systématique au fil des ans, mais les données recueillies depuis 1985, de même que des sondages récents réalisés plusieurs fois selon une même structure, facilitent beaucoup l’analyse que nous pouvons maintenant faire de l’évolution de cette satisfaction dans les diverses régions du pays. Dans cet article, je montre que, depuis 25 ans, la satisfaction face à la vie s’est beaucoup accrue au Québec quand on compare cette province au reste du Canada, et que l’ampleur de cette hausse du bienêtre subjectif est comparable à l’effet qu’aurait la multiplication par trois du revenu moyen des ménages.