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

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

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

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 ± 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 ± 0.58 mm/year, after correction for air pressure and GIA. This rate compares to a value of 2.79 ± 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"

In the paper “Long-term and recent changes in sea level in the Falkland Islands” 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 −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 −0.69 and −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 ± 0.35 mm/yr in paragraphs 1, 47, 55, and 61 should be +0.92 ± 0.35 mm/yr, the corresponding rate between 1842 and the midpoint of recent data of 1.06 ± 0.22 mm/yr in paragraphs 48 and 55 should be 1.23 ± 0.22 mm/yr, and the corresponding rate since 1992 reported as 2.51 ± 0.58 mm/yr in paragraphs 1 and 52 becomes 2.60 ± 0.58 mm/yr. The middle of paragraph 63 becomes “The 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.” 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

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

The Acclaim Programme in the South Atlantic and Southern Oceans

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

Measuring global mean sea level changes with surface drifting buoys

Combining ocean model data and in-situ Lagrangian data, I show that an array of surface drifting buoys tracked by a Global Navigation Satellite System (GNSS), such as the Global Drifter Program, could provide estimates of global mean sea level (GMSL) and its changes, including linear decadal trends. For a sustained array of 1250 globally distributed buoys with a standardized design, I demonstrate that GMSL decadal linear trend estimates with an uncertainty less than 0.3 mm yr$^{-1}$ could be achieved with GNSS daily random error of 1.6 m or less in the vertical direction. This demonstration assumes that controlled vertical position measurements could be acquired from drifting buoys, which is yet to be demonstrated. Development and implementation of such measurements could ultimately provide an independent and resilient observational system to infer natural and anthropogenic sea level changes, augmenting the on-going tide gauge and satellites records.Comment: resubmitted to AGU Geophysical Research Letter