scholarly journals Are long tide gauge records in the wrong place to measure global mean sea level rise?

2016 ◽  
Vol 43 (19) ◽  
pp. 10,403-10,411 ◽  
Author(s):  
P. R. Thompson ◽  
B. D. Hamlington ◽  
F. W. Landerer ◽  
S. Adhikari
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Tide Gauge Records ◽  
Mean Sea Level ◽  
Global Mean Sea Level ◽  
Wrong Place ◽  
Global Mean

scholarly journals Reassessment of 20th century global mean sea level rise

2017 ◽  
Vol 114 (23) ◽  
pp. 5946-5951 ◽  
Author(s):  
Sönke Dangendorf ◽  
Marta Marcos ◽  
Guy Wöppelmann ◽  
Clinton P. Conrad ◽  
Thomas Frederikse ◽  
...  
Keyword(s):  
Sea Level ◽  
20Th Century ◽  
Tide Gauge ◽  
Equal Proportion ◽  
Tide Gauge Records ◽  
Intergovernmental Panel ◽  
Mean Sea Level ◽  
Vertical Land Motion ◽  
Global Mean Sea Level ◽  
Global Mean

The rate at which global mean sea level (GMSL) rose during the 20th century is uncertain, with little consensus between various reconstructions that indicate rates of rise ranging from 1.3 to 2 mm⋅y−1. Here we present a 20th-century GMSL reconstruction computed using an area-weighting technique for averaging tide gauge records that both incorporates up-to-date observations of vertical land motion (VLM) and corrections for local geoid changes resulting from ice melting and terrestrial freshwater storage and allows for the identification of possible differences compared with earlier attempts. Our reconstructed GMSL trend of 1.1 ± 0.3 mm⋅y−1 (1σ) before 1990 falls below previous estimates, whereas our estimate of 3.1 ± 1.4 mm⋅y−1 from 1993 to 2012 is consistent with independent estimates from satellite altimetry, leading to overall acceleration larger than previously suggested. This feature is geographically dominated by the Indian Ocean–Southern Pacific region, marking a transition from lower-than-average rates before 1990 toward unprecedented high rates in recent decades. We demonstrate that VLM corrections, area weighting, and our use of a common reference datum for tide gauges may explain the lower rates compared with earlier GMSL estimates in approximately equal proportion. The trends and multidecadal variability of our GMSL curve also compare well to the sum of individual contributions obtained from historical outputs of the Coupled Model Intercomparison Project Phase 5. This, in turn, increases our confidence in process-based projections presented in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

scholarly journals A new assessment of global mean sea level from altimeters highlights a reduction of global trend from 2005 to 2008

2009 ◽  
Vol 6 (1) ◽  
pp. 31-56 ◽  
Author(s):  
M. Ablain ◽  
A. Cazenave ◽  
G. Valladeau ◽  
S. Guinehut
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Mean Sea Level ◽  
Error Budget ◽  
Isostatic Adjustment ◽  
Global Trend ◽  
Tide Gauge Measurements ◽  
Global Mean Sea Level ◽  
Global Mean

Abstract. A new error budget assessment of the global Mean Sea Level (MSL) determined by TOPEX/Poseidon and Jason-1 altimeter satellites between January 1993 and June 2008 is presented. We discuss all potential errors affecting the calculation of the global MSL rate. We also compare altimetry-based sea level with tide gauge measurements over the altimetric period. This allows us to provide a realistic error budget of the MSL rise measured by satellite altimetry. These new calculations highlight a reduction in the rate of sea level rise since 2005, by ~2 mm/yr. This represents a 60% reduction compared to the 3.3 mm/yr sea level rise (glacial isostatic adjustment correction applied) measured between 1993 and 2005. Since November 2005, MSL is accurately measured by a single satellite, Jason-1. However the error analysis performed here indicates that the recent reduction in MSL rate is real.

scholarly journals The imprints of contemporary mass redistribution on local sea level and vertical land motion observations

Solid Earth ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 1971-1987 ◽  
Author(s):  
Thomas Frederikse ◽  
Felix W. Landerer ◽  
Lambert Caron
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Tide Gauge Records ◽  
Mean Sea Level ◽  
Sea Floor ◽  
Vertical Land Motion ◽  
Mass Redistribution ◽  
Global Mean Sea Level ◽  
The Impact ◽  
Global Mean

Abstract. Observations from permanent Global Navigation Satellite System (GNSS) stations are commonly used to correct tide-gauge observations for vertical land motion (VLM). We combine GRACE (Gravity Recovery and Climate Experiment) observations and an ensemble of glacial isostatic adjustment (GIA) predictions to assess and evaluate the impact of solid-Earth deformation (SED) due to contemporary mass redistribution and GIA on VLM trends derived from GNSS stations. This mass redistribution causes relative sea-level (RSL) and SED patterns that not only vary in space but also exhibit large interannual variability signals. We find that for many stations, including stations in coastal locations, this deformation causes VLM trends on the order of 1 mm yr−1 or higher. In multiple regions, including the Amazon Basin and large parts of Australia, the SED trend flips sign between the first half and second half of the 15-year GRACE record. GNSS records often only span a few years, and due to these interannual variations SED causes substantial biases when the linear trends in these short records are extrapolated back in time. We propose a new method to avoid this potential bias in the VLM-corrected tide-gauge record: instead of correcting tide-gauge records for the observed VLM trend, we first remove the effects from GIA and contemporary mass redistributions from the VLM observations before computing the VLM trend. This procedure reduces the extrapolation bias induced by SED, and it also avoids the bias due to sea-floor deformation: SED includes net sea-floor deformation, which is ignored in global-mean sea-level reconstructions based on VLM-corrected tide-gauge data. We apply this method to 8166 GNSS stations. With this separation, we are able to explain a large fraction of the discrepancy between observed sea-level trends at multiple long tide-gauge records and the global-mean sea-level trend from recent reconstructions.

scholarly journals A new assessment of the error budget of global mean sea level rate estimated by satellite altimetry over 1993–2008

Ocean Science ◽  
2009 ◽  
Vol 5 (2) ◽  
pp. 193-201 ◽  
Author(s):  
M. Ablain ◽  
A. Cazenave ◽  
G. Valladeau ◽  
S. Guinehut
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Mean Sea Level ◽  
Error Budget ◽  
Isostatic Adjustment ◽  
Tide Gauge Measurements ◽  
Global Mean Sea Level ◽  
Global Mean

Abstract. A new error budget assessment of the global Mean Sea Level (MSL) determined by TOPEX/Poseidon and Jason-1 altimeter satellites between January 1993 and June 2008 is presented using last altimeter standards. We discuss all potential errors affecting the calculation of the global MSL rate. We also compare altimetry-based sea level with tide gauge measurements over the altimetric period. Applying a statistical approach, this allows us to provide a realistic error budget of the MSL rise measured by satellite altimetry. These new calculations highlight a reduction in the rate of sea level rise since 2005, by ~2 mm/yr. This represents a 60% reduction compared to the 3.3 mm/yr sea level rise (glacial isostatic adjustment correction applied) measured between 1993 and 2005. Since November 2005, MSL is accurately measured by a single satellite, Jason-1. However the error analysis performed here indicates that the recent reduction in MSL rate is real.

The causes of sea-level rise since 1900

2020 ◽  
Author(s):  
Thomas Frederikse ◽  
Felix Landerer ◽  
Lambert Caron ◽  
Surendra Adhikari ◽  
David Parkes ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Greenland Ice Sheet ◽  
Mean Sea Level ◽  
Terrestrial Water ◽  
Global Mean Sea Level ◽  
Global Mean

<p>Global-mean sea level (GMSL) has been rising unsteadily by about 1.5 mm/yr since 1900, but the underlying causes of this trend and the multi-decadal variations are still poorly understood. Over the last few years, updated estimates of the underlying contributing processes have become available, notably for the contributions from glaciers, terrestrial water storage, the Greenland Ice Sheet, and thermal expansion. In parallel, 20th-century GMSL estimates have been revised downward as a result of improved reconstruction approaches, spatial bias correction schemes, and the inclusion of estimates of local vertical land motion at tide-gauge locations. Together, both developments now necessitate the re-evaluation of the GMSL budget to determine whether the observed sea-level rise since 1900 can be reconciled with the estimated sum of contributing processes. </p><p>Here we present a probabilistic framework to reconstruct and budget sea level with independent observations considering their inherent uncertainties. We find that the sum of thermal expansion, ice-mass loss and terrestrial water storage changes is consistent with the trends and multi-decadal variability in observed sea level on both global and basin scales, which we reconstruct from tide-gauge records. </p><p>Glacier-dominated cryospheric mass loss has caused twice as much sea-level rise as thermal expansion since 1900. Glacier and Greenland Ice Sheet mass loss well explains the high rates typically seen in global sea-level reconstructions during the 1930s, while a sharp increase in water impoundment by artificial reservoirs has been the dominant contributor to lower-than-average rates during the 1970s. The acceleration since the 1970s is caused by both thermal expansion and increased Greenland mass loss. No additional large-scale deep ocean warming or additional mass loss from Antarctica are needed to explain 20th-century changes in global-mean sea level. This assessment reconciles the magnitude of observed global-mean sea-level rise since 1900 with estimates of underlying processes.</p>

Effect of the processing methodology on satellite altimetry-based global mean sea level rise over the Jason-1 operating period

2013 ◽  
Vol 88 (4) ◽  
pp. 351-361 ◽  
Author(s):  
Olivier Henry ◽  
Michael Ablain ◽  
Benoit Meyssignac ◽  
Anny Cazenave ◽  
Dallas Masters ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Operating Period ◽  
Mean Sea Level ◽  
Global Mean Sea Level ◽  
Global Mean

The contribution of the East Antarctic Ice Sheet to future sea level rise

2020 ◽  
Author(s):  
Jim Jordan ◽  
Hilmar Gudmundsson ◽  
Adrian Jenkins ◽  
Chris Stokes ◽  
Stewart Jamieson ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Antarctic Ice Sheet ◽  
Mean Sea Level ◽  
Potential Contributor ◽  
Global Mean Sea Level ◽  
Global Mean ◽  
East Antarctic Ice Sheet

<p>The East Antarctic Ice Sheet (EAIS) is the single largest potential contributor to future global mean sea level rise, containing a water mass equivalent of 53 m. Recent work has found the overall mass balance of the EAIS to be approximately in equilibrium, albeit with large uncertainties. However, changes in oceanic conditions have the potential to upset this balance. This could happen by both a general warming of the ocean and also by shifts in oceanic conditions allowing warmer water masses to intrude into ice shelf cavities.</p><p>We use the Úa numerical ice-flow model, combined with ocean-melt rates parameterized by the PICO box mode, to predict the future contribution to global-mean sea level of the EAIS. Results are shown for the next 100 years under a range of emission scenarios and oceanic conditions on a region by region basis, as well as for the whole of the EAIS. </p>

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