Tide gauge datum continuity at Brest since 1711: France's longest sea‐level record

Abstract

The issue of a possible tide gauge datum discontinuity at Brest, caused by the bombing of the city in August 1944, is discussed. This issue is very important, as many scientists have used this long record to derive a long‐term sea level trend estimate for use within global sea level rise studies. A detailed analysis of historical leveling information, and comparison of sea level data between adjacent stations, proved to be worthwhile, even beyond this initial scope of the study: it led to an accurate datum connection between recently rediscovered 18th century sea level data (back to 1711) and those of the present day. The study provides additional evidence that the onset of recent rapid sea level rise most likely took place in the late 19th century, in agreement with the nearby Liverpool sea‐level record and with independent results from sediment cores collected in salt marshes located in both hemispheres.

Observed mean sea level changes around the North Sea coastline from 1800 to present

“…Araújo (2005), Haigh (2009) and Haigh et al (2009) analysed MSL records from tide gauge sites around the English Channel. Araújo et al (2008) and Wöppelmann et al (2006Wöppelmann et al ( , 2008 considered data sets from single stations (i.e. Newlyn and Brest) to assess long-term sea level changes in the same region.…”

Evidence for Century-Timescale Acceleration in Mean Sea Levels and for Recent Changes in Extreme Sea Levels

“…Figure 1(a) is adapted from a similar figure shown in Woodworth (1999) and the IPCC Third Assessment Report (TAR, Church et al 2001). Important modifications are that the Amsterdam record has been extended with the use of data from Den Helder, the Brest time series has been extended back to the 18 th century (Pouvreau 2008;Wöppelmann et al 2008), the Liverpool time series now attempts to reflect MSL rather than mean high water change, and the Stockholm record of Ekman (1988) has been updated using data from the Permanent Service for Mean Sea Level (PSMSL, www.psmsl.org, Woodworth and Player 2003). If one applies a secondorder fit (a + bt + ct 2 where 't' is time and 'c' must be doubled to give acceleration) to each time series, then quadratic coefficients 'c' of order 0.005 mm/year 2 are obtained, all the records shown providing evidence for a long term acceleration in sea level, and suggesting that the acceleration commenced around the end of the 19 th century or a little later.…”

Global Warming Advocacy Science: A Cross Examination

“…300 Even under relatively pessimistic assumptions about continuing increases in ghg's, assumptions that eventually generate an annual sea level increase of 4 mm/year, the IPCC's 2007 AR projected an increase in global sea level of at most .44 meters, or about a foot and a half, by 2090. 301 Since then, a number of studies have appeared that tend to show that the IPCC may not have been as conservative as it claimed: Holgate 302 estimated that the sea level rise during the early twentieth century was 2.0 mm/year, much larger than the 1.45 mm/year estimate he found for the latter half of the twentieth century; Jevrejeva et al 303 find evidence that the sea level increase began over 200 years ago; Woppleman et al 304 "At best, the determination and attribution of global-mean sea level change lies at the very edge of knowledge and technology. The most urgent job would appear to be the accurate determination of the smallest temperature and salinity changes that can be determined with statistical significance, given the realities of both the observation base and modeling approximations.…”