6 resultados para weather changes

em Deakin Research Online - Australia


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In this paper, we focus on the effects of weather, such as sunshine, as an exogenous shifter of happiness using happiness data at the individual level, and estimate sunshine as a predictor of happiness. Then we relate the predicted happiness to risk-taking. By doing so, we estimate a relationship, stronger than a simple correlation, between happiness and risky behavior. Weather changes, and sunshine in particular, have substantial influences on personal happiness. However, unexpected weather changes appear to be more important than expected changes for happiness. We include several risk measures such as subjective risk-taking and financial assets in our analysis. Happier people appear to be more risk-averse in general and more specifically in financial decisions, and choose accordingly safer investments. This might be explained by the fact that happy people take more time for making decisions and have more self-control. In addition, predicted happiness affects expectations about longevity and inflation. Happy people expect to live longer and accordingly seem more concerned about the future than the present, and expect less inflation.

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Previous studies of the remarkable seasonal colour changes of Blue Lake, Mount Gambier, South Australia have speculated on the roles of weather and solar elevation in this phenomenon. In this study the influence of weather and solar elevation on apparent colour is examined. Solar elevation and some weather variables were found to have a statistically significant influence, particularly when Blue Lake is undergoing transition from its blue to grey stage. However, the proportion of the overall variation in colour explained by solar elevation and weather was only 16%, so it is concluded that in-lake properties are probably the main determinants of colour.

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Events happening in one season can affect life-history traits at (the) subsequent season(s) by carry-over effects. Wintering conditions are known to affect breeding success, but few studies have investigated carry-over effects on survival. The Eurasian oystercatcher Haematopus ostralegus is a coastal wader with sedentary populations at temperate sites and migratory populations in northern breeding grounds of Europe. We pooled continental European ringing-recovery datasets from 1975 to 2000 to estimate winter and summer survival rates of migrant and resident populations and to investigate long-term effects of winter habitat changes. During mild climatic periods, adults of both migratory and resident populations exhibited survival rates 2% lower in summer than in winter. Severe winters reduced survival rates (down to 25% reduction) and were often followed by a decline in survival during the following summer, via short-term carry-over effects. Habitat changes in the Dutch wintering grounds caused a reduction in food stocks, leading to reduced survival rates, particularly in young birds. Therefore, wintering habitat changes resulted in long-term (>10 years) 8.7 and 9.4% decrease in adult annual survival of migrant and resident populations respectively. Studying the impact of carry-over effects is crucial for understanding the life history of migratory birds and the development of conservation measures.

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The Australian coast is rich in history and is scattered with coastal settlements amongst a contrasting landscape with infinite visual and ecological diversity. These attributes provide the opportunity to create sustainable and resilient settlements, linking the wholeness of a place to the foundation of living in harmony with nature. On the contrary the coastal regions of Australia are facing dynamic changes of population growth including the looming impact of a changing climate. Acknowledging these challenges, the Australian Government highlighted that one of the key requirements for a sustainable future is to establish sustainable settlements that are resilient against the impacts of climate change. Recent government studies and reports highlighted various possible impacts to the Australian coast and regional settlements due to sea level rise with associated coastal recession, extreme weather events, flooding, and prolonged heat waves. Various adaptation frameworks are proposed to deal with this issue, but very few consider the relationship between ecological systems and human built environments. The resilience planning of settlements must consider the co-evolution of human and nature under future climate effects. This paper is thus seeking answers to the question: How can the theoretical principles of Design with Nature (McHarg, 1967) and The Nature of Order (Alexander, 1980) provide for input to a adaptation model for settlements along the coast? Reflecting on a literature review of these two well established theories, the author select key principles from both as input to a ecological design based adaptation model for coastal settlements, which establishes a system of unfolding steps to create sustainable communities that connect with the landscape, and are resilient against future impacts of change.

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Because energy reserves limit flight range, wind assistance may be of crucial importance for migratory birds. We tracked eight Bewick's swans Cygnus columbianus bewickii, using 95-g satellite transmitters with altimeters and activity sensors, during their spring migration from Denmark to northern Russia in 1996. During the 82 occasions where a swan's location was recorded in flight, average flight altitude was 165 m a.s.1. with a maximum of 759 m a.s.1., despite winds often being more favourable at higher altitudes. We also counted Bewick's swans departing from the Gulf of Finland and subsequently passing an observatory in the next major stop-over area 800 km further north in the White Sea, northern Russia, during the springs of 1994, 1995 and 1996. A comparison of these counts with wind data provided evidence for Bewick's swans using favourable changes in wind conditions to embark on migration. Changes in the numbers of birds arriving in the White Sea correlated best with favourable changes in winds in the Gulf of Finland 1 day earlier. Again, migratory volume showed a correlation with winds at low altitudes only, despite wind conditions for the swans being more favourable at high altitudes. We conclude that the relatively large Bewick's swan tends to gear its migration to wind conditions at low altitude only. We argue that Bewick's swans do not climb to high altitudes because of mechanical and physiological limitations with respect to the generation of power for flight and to avoid rapid dehydration.