984 resultados para Pacific Coast (North America)


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This present study investigates the influence of western Pacific tropical cyclone activity as possible centers of anomalous tropical heating on the large-scale circulation over the Pacific region. The characterization of tropical cyclone activity via an index based on anomalous 700 mb zonal wind is described first. Patterns of anomalous large-scale extratropical circulation anomalies based on composites of similar periods of tropical cyclone activity are then presented, followed by general conclusions.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): As part of a study of climatic influences on landslide initiation, a statistical analysis of long-term (>40 years) records of daily rainfall from 24 Pacific coastal stations, from San Diego to Cape Flattery, disclosed an unexpected result - the square root of the daily rainfall closely approximates a normal distribution function. ... This paper illustrates the use of the square-root-normal distribution to analyze variations in precipitation along the mainland United States Pacific Coast with examples of orographic enhancement, rain shadows, and increase in precipitation frequency with geographic latitude.

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Inferring how the Pleistocene climate oscillations have repopulated the extant population structure of Chondrus crispus Stackh. in the North Atlantic Ocean is important both for our understanding of the glacial episode promoting diversification and for the conservation and development of marine organisms. C. crispus is an ecologically and commercially important red seaweed with broad distributions in the North Atlantic. Here, we employed both partial mtDNA Cox1 and nrDNA internal transcribed spacer region 2 (ITS2) sequences to explore the genetic structure of 17 C. crispus populations from this area. Twenty-eight and 30 haplotypes were inferred from these two markers, respectively. Analysis of molecular variance (AMOVA) and of the population statistic Theta(ST) not only revealed significant genetic structure within C. crispus populations but also detected significant levels of genetic subdivision among and within populations in the North Atlantic. On the basis of high haplotype diversity and the presence of endemic haplotypes, we postulate that C. crispus had survived in Pleistocene glacial refugia in the northeast Atlantic, such as the English Channel and the northwestern Iberian Peninsula. We also hypothesize that C. crispus from the English Channel refugium repopulated most of northeastern Europe and recolonized northeastern North America in the Late Pleistocene. The observed phylogeographic pattern of C. crispus populations is in agreement with a scenario in which severe Quaternary glaciations influenced the genetic structure of North Atlantic marine organisms with contiguous population expansion and locally restricted gene flow coupled with a transatlantic dispersal in the Late Pleistocene.

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Before the mass migrations from Ireland in the nineteenth century, earlier waves of migration in the eighteenth century saw significant numbers of people leave Ireland, predominantly from Ulster, to settle in North America. This article, using as its principal data source the Belfast News Letter ( BNL), its letters, advertisements and reports, focuses firstly on reconstructing the late eighteenth-century migration process and voyage, highlighting the barriers represented by the Atlantic Ocean. In addition to the challenges of the sea, there were problems with the ships, the ever-present danger of disease and also threats from other vessels, from privateers to press gangs. The voyage was recognized as a ‘universal dread’, and the risks taken to ‘dare the boist’rous main’ were perhaps not minimized in the pages of the BNL, whose editorial stance was antipathetic to the migration for the potential harm it caused to Ulster by removing so many of its industrious young. The second part of this article goes on to consider the newspaper’s and others’ vested interests in the emigration process, demonstrates how these were manifested in the press and sets the coverage of this very significant early emigration flow within the context of contemporary religious and colonial discourses at a period of very lively transatlantic interactions.