See E.W. Leuliette, R.S. Nerem, and G.T. Mitchum, «Results of TOPEX / Poseidon and Jason - 1 calibration to construct a continuous record of mean sea level,» Marine Geodesy 27:79 - 94, 2004, and B.D. Beckley, F.G. Lemoine, S.B. Luthcke, R.D. Ray, and N.P. Zelensky, «A reassessment of global and
regional mean sea level trends from TOPEX and Jason - 1 altimetry based on revised reference frame and orbits,» Geophysical Research Letters 34 (14): L14608, 2007.
Although the tide gauge data are still too limited, both in time and space, to determine conclusively that there is a 60 - year oscillation in GMSL, the possibility should be considered when attempting to interpret the acceleration in the rate of global and
regional mean sea level rise.
The uncertainty in the global mean sea level trend is estimated to be of ± 0.5 mm / yr in a confidence interval of 90 % (1.65 sigma), whereas the uncertainty of
the regional mean sea level trends is of the order of 2 - 3 mm / yr with values as low as 0.5 mm / yr or as high as 5.0 mm / yr depending on the region considered (Legeais et al., 2018, under review).
The map of
regional mean sea level trends provides an overview of variations in the rates of relative local mean sea level observed at long - term tide stations (based on a minimum of 30 years of data in order to account for long - term sea level variations and reduce errors in computing sea level trends based on monthly mean sea level).
Not exact matches
Satellite altimetry methods developed at NOC play a crucial role in helping improve storm surge models and map out
regional changes in
mean sea level.»
The physics underlying
sea -
level change, which can be mind - bending and counterintuitive,
mean there is tremendous
regional variability in present and future
sea -
level changes.
In this regard, I would observe that at least one important AGW effect, rising
sea level, does not depend on a specific
regional outcome so much as on global
mean T. (At least, I think this is so (because my understanding is that most of the rise comes from lower density of warmer water, not from melting ice sheets — though again, not 100 % sure on this point)-RRB-.
As in the past,
sea level change in the future will not be geographically uniform, with
regional sea level change varying within about ± 0.15 m of the
mean in a typical model projection.
«Trends and acceleration in global and
regional sea levels since 1807» «Evaluation of the global
mean sea level budget between 1993 and 2014» «Considerations for estimating the 20th century trend in global
mean sea level» «New estimate of the current rate of
sea level rise from a
sea level budget approach» «Reassessment of 20th century global
mean sea level rise» «The increasing rate of global
mean sea -
level rise during 1993 — 2014» «Unabated global
mean sea -
level rise over the satellite altimeter era» «An increase in the rate of global
mean sea level rise since 2010»
Analyses of tide gauge and altimetry data by Vinogradov and Ponte (2011), which indicated the presence of considerably small spatial scale variability in annual
mean sea level over many coastal regions, are an important factor for understanding the uncertainties in
regional sea -
level simulations and projections at sub-decadal time scales in coarse - resolution climate models that are also discussed in Chapter 13.
Scientists have recently observed major changes in these glaciers: several have broken up at the ocean end (the terminus), and many have doubled the speed at which they are retreating.2, 5 This has
meant a major increase in the amount of ice and water they discharge into the ocean, contributing to
sea -
level rise, which threatens low - lying populations.2, 3,5 Accelerated melting also adds freshwater to the oceans, altering ecosystems and changing ocean circulation and
regional weather patterns.7 (See Greenland ice sheet hotspot for more information.)
Different approaches have been used to compute the
mean rate of 20th century global
mean sea level (GMSL) rise from the available tide gauge data: computing average rates from only very long, nearly continuous records; using more numerous but shorter records and filters to separate nonlinear trends from decadal - scale quasi-periodic variability; neural network methods; computing
regional sea level for specific basins then averaging; or projecting tide gauge records onto empirical orthogonal functions (EOFs) computed from modern altimetry or EOFs from ocean models.
What does «average global
sea -
level rise»
mean, and what are the global and
regional consequences when all the ice melts on the far - away West Antarctic Ice Sheet?
To obtain information about
mean sea level changes at higher resolution is currently not practical; a
regional model such as that of Kauker (1998) would be needed.