376 resultados para contemporary Pacific
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Climate modeling using coastal tree-ring chronologies has yielded the first summer temperature reconstructions for coastal stations along the Gulf of Alaska and the Pacific Northwest. These land temperature reconstructions are strongly correlated with nearby sea surface temperatures, indicating large-scale ocean-atmospheric influences. Significant progress has also been made in modeling winter land temperatures and sea surface temperatures from coastal and shipboard stations. In addition to temperature, the pressure variability center over the central North Pacific Ocean (PAC), which is related to the strength and location of the Aleutian Low pressure system, could be extended using coastal tree rings.
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The appendices include the workshop agenda, a list of poster presentations, and a list of attendees.
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By how much does changing radiation from the Sun influence Earth's climate compared with other natural and anthropogenic processes? Answering this question is necessary for making policy regarding anthropogenic global change, which must be detected against natural climate variability. Current knowledge of the amplitudes and time scales of solar radiative output variability available from contemporary solar monitoring and historical reconstructions can help specify climate forcing by changing radiation over multiple time scales.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): It is increasingly apparent that a major reorganization of the Northeast Pacific biota transpired following a climatic "regime shift" in the mid-1970s. In this paper, we characterize the effects of interdecadal climate forcing on the oceanic ecosystems of the northeastern Pacific Ocean.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Reconstruction of proxy variables from massive corals and varved sediments of the eastern Pacific allow us to compare variability in the ocean climate from equatorial and mid-latitude sites for a significantly longer period than is available from the instrumental record.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): The dynamics and predictability of decadal climate variability over the North Pacific and North America are investigated by analyzing various observational datasets and the output of a state-of-the-art coupled ocean-atmosphere general circulation model, which was integrated for 120 years.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): In this study we use ocean and atmosphere datasets from observations and from an ocean general circulation model integration to examine decadal time scale variability that is centered in the Pacific basin. We know that decadal variability is likely to have a strong expression in the Pacific basin; for example, a marked "shift" of cool season climate in the mid-1970s introduced major changes in Pacific SST and atmospheric circulation, along with many other physical and biological properties.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Researchers have shown a step-like increase in worldwide sea surface temperatures (SSTs) in the mid-1970s. Wintertime (December through March) polar-front jet stream positions in the North Pacific will be presented for six moderate-to-very-strong El Niño events - three before the winter of 1975-76 (1965-66, 1968-69, 1972-73) and three after (1982-83, 1986-87, 1991-92).
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Past work has shown that surface zonal equatorial wind stress, zonally integrated from one side of the Pacific to the other, is the key variable for estimating long-term El Niño behavior in the eastern Pacific. ... We used detrended COADS pressure in the eastern and western equatorial Pacific and post-1960 detrended Florida State University equatorial wind stress zonally averaged across the Pacific to verify this relationship.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Observations of climate variables in the tropical Pacific region are examined for the period 1970-1994. We look at a variety of climate variables, including upper ocean temperatures, surface wind stress, precipitation, and the Southern Oscillation Index (SOI) and find evidence for two distinct decadal-scale warmings in the tropical Pacific ocean-atmosphere climate system during this period.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Catch of coho salmon off the coast of Washington and Oregon since 1925 appears to be related to large-scale events in the atmosphere, which in turn affect ocean currents and coastal upwelling intensities in the northeastern Pacific. At least two time scales of variations can be identified. The first is that of the El Nino/Southern Oscillation phenomenon giving rise to an irregular cycle of between 3 to 7 years. ... The second time scale of variation seems to have a periodicity of about 20 years, although this is based on a limited dataset. ... This paper endeavors to describe how, if real, these atmospheric/oceanic effects are integrated and might affect the salmon catch. The possibility must also be considered that the atmospheric events are symbiotically related to the oceanic events and, further, that both may be enmeshed in even longer-term variability of climate.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Indices of the relative abundance of bluefin tuna in the western and eastern Pacific show decadal variation in the proportion of bluefin making trans-Pacific migrations out of the western Pacific.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Selected hydrometeorological (HM) data for the Pacific Northwest and atmospheric and North Pacific sea-surface temperature (SST) data are examined for three successive periods that are subsets of the historical record to estimate if their characteristics have changed.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Synoptic dendroclimatology uses dated tree rings to study and reconstruct climate from the viewpoint of the climate's weather components and their relationship to atmospheric circulation. This approach defines a connection between large-scale circulation and ring-width variation at local sites using correlation fields, composite maps, indexing, and other circulation-based methodologies.