1,225 research outputs found

    The tilt of mean sea level along the east coast of North America

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    The tilt of mean sea level along the North American east coast has been a subject of debate for many decades. Improvements in geoid and ocean circulation models, and GPS positioning of tide gauge benchmarks, provide an opportunity to produce new tilt estimates. Tilts estimated using tide gauge measurements referenced to high-resolution geoid models (the geodetic approach) and ocean circulation models (the ocean approach) are compared. The geodetic estimates are broadly similar, with tilts downward to the north through the Florida Straits and at Cape Hatteras. Estimates from the ocean approach show good agreement with the geodetic estimates, indicating a convergence of the two approaches and resolving the long standing debate as to the sign of the tilt. These tilts differ from those used by Yin and Goddard (2013) to support a link between changing ocean circulation and coastal sea level rise

    On the Availability of European Mean Sea Level Data

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    Over the past two years a major effort has been made to bring up-to-date the European Mean Sea Level (MSL) data set with the result that significant updates have been obtained from all European coastlines, except one, which are known to operate tide gauges. Several important historical time series, not hitherto included in the Permanent Service for Mean Sea Level (PSMSL) data bank, have also been acquired. The resulting total European MSL data set, which is available for analysis by any interested research worker, will be employed subsequently in extensive climatological and geological investigations of European MSL interannual variability and long-term trends. This report presents a review of the quantity and quality of available European MSL data with particular emphasis on the recently-obtained information

    Outstanding Educational Performance Awards: Highlighting High Achieving Arkansas Schools, 2010

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    So, in this Arkansas Education Report (AER) we aim to highlight excellent performance and give our congratulations. To that end, we are happy to highlight many high performing schools around the state in our now-annual AER entitled the Outstanding Educational Performance Awards

    Long-term and recent changes in sea level in the Falkland Islands

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    Mean sea level measurements made at Port Louis in the Falkland Islands in 1981-2, 1984 and 2009, together with values from the nearby permanent tide gauge at Port Stanley, have been compared to measurements made at Port Louis in 1842 by James Clark Ross. The long-term rate of change of sea level is estimated to have been +0.75 Ā± 0.35 mm/year between 1842 and the early 1980s, after correction for air pressure effects and for vertical land movement due to Glacial Isostatic Adjustment (GIA). The 2009 Port Louis data set is of particular importance due to the availability of simultaneous information from Port Stanley. The data set has been employed in two ways, by providing a short recent estimate of mean sea level itself, and by enabling the effective combination of measurements at the two sites. The rate of sea level rise observed since 1992, when the modern Stanley gauge was installed, has been larger at 2.51 Ā± 0.58 mm/year, after correction for air pressure and GIA. This rate compares to a value of 2.79 Ā± 0.42 mm/year obtained from satellite altimetry in the region over the same period. Such a relatively recent acceleration in the rate of sea level rise is consistent with findings from other locations in the southern hemisphere and globall

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    Correction to "Long-term and recent changes in sea level in the Falkland Islands"

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    In the paper ā€œLong-term and recent changes in sea level in the Falkland Islandsā€ by P. L. Woodworth et al. (Journal of Geophysical Research, 115, C09025, doi:10.1029/2010JC006113, 2010), in paragraph 47 we adopted a value of āˆ’0.52 mm/yr for the estimated rate of present-day sea level change in the Falkland Islands due to glacial isostatic adjustment (GIA). This value was used to remove the contributions of GIA to our measurements of historical and recent rates of sea level change. However, it was based on a misreading of the data file of Peltier [2004] on the Permanent Service for Mean Sea Level Web site (http://www.psmsl.org/train_and_info/geo_signals/gia/peltier). More reasonable values to apply to the observed changes since the mid-nineteenth century and in recent years would be āˆ’0.69 and āˆ’0.61 mm/yr respectively. Consequently, the long-term rate of sea level change between 1842 and the early 1980s, after correction for air pressure effects and for GIA, reported as +0.75 Ā± 0.35 mm/yr in paragraphs 1, 47, 55, and 61 should be +0.92 Ā± 0.35 mm/yr, the corresponding rate between 1842 and the midpoint of recent data of 1.06 Ā± 0.22 mm/yr in paragraphs 48 and 55 should be 1.23 Ā± 0.22 mm/yr, and the corresponding rate since 1992 reported as 2.51 Ā± 0.58 mm/yr in paragraphs 1 and 52 becomes 2.60 Ā± 0.58 mm/yr. The middle of paragraph 63 becomes ā€œThe Stanley data suggest that the rate of change of sea level in East Falkland since 1992 has been approximately 2.6 mm/yr, a rate supported by information from satellite altimetry.ā€ These small GIA model corrections have no bearing on the main findings of our paper on the difference in the rates of sea level change between the historical (1842 to present-day) and recent (last 2 decades) epoch

    Spotlights on Success: Traits and Strategies of Five High-Growth Schools in Arkansas

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    Successful schools are those which best educate the students, regardless of background. They are not those with students who come in well-educated but show only slight improvement, nor are they schools which use the disadvantage as an excuse for continued low levels of achievement. Instead, successful schools are those which advance the learning of all their children beyond what is expected

    Seiches around the Shetland Islands

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    Sea level records have been obtained from a dozen tide gauges deployed around the Shetland Islands, and the high-frequency components of each record have been analysed to determine how the amplitudes and periods of seiches vary from place to place. We have found that seiches occur almost everywhere, although with different periods at different locations, and sometimes with amplitudes exceeding several decimetres. Spectral analysis shows that two or more modes of seiching are present at some sites. The study attempts to explain, with the help of a numerical model, why seiches with particular periods are observed at each location, and what forcings are responsible for them. In particular, we have revisited an earlier study of seiches on the east coast of Shetland by Cartwright and Young (Proc R Soc Lond A 338:111ā€“128, 1974) and find no evidence to support the theory that they proposed for their generation. In addition, we have investigated how often and why the largest seiche events occur at Lerwick (with trough-to-crest wave heights of about 1 m), taking advantage of its long sea level record. Seiches (and other types of high-frequency sea level variability) are often ignored in studies of sea level changes and their coastal impacts. And yet they can be large enough to contribute significantly to the extreme sea levels that have major impacts on the coast. Therefore, our Shetland research serves as a case study of the need to have a fuller understanding of the climatology of seiches for the whole world coastline

    The Acclaim Programme in the South Atlantic and Southern Oceans

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    The ACCLAIM sea level network consists of six coastal tide gauge sites and approximately a dozen bottom pressure stations in the South Atlantic and Southern Oceans. Since 1985, an extensive dataset of regional sea level and bottom pressure measurements has been acquired. This dataset is being employed at POL in a number of scientific analyses and is available to any interested research worker through the World Ocean Circulation Experiment. In this paper, a review is given of the development and status of the ACCLAIM network and the technology installed at each site. Plans are presented for developments over the next 1-2 years
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