scholarly journals Impact of Ocean Domain Definition on Sea Level Budget

2021 ◽  
Vol 13 (16) ◽  
pp. 3206
Author(s):  
Taehwan Jeon
Keyword(s):  
Sea Level ◽  
Volume Expansion ◽  
Alternative Definition ◽  
Sea Level Changes ◽  
Steric Sea Level ◽  
Argo Float ◽  
Domain Definition ◽  
Global Trend ◽  
Definition Of ◽  
The Impact

Total sea level changes from space radar altimetry are mainly decomposed into two contributions of mass addition and volume expansion of oceans, measured by GRACE space gravimeter and Argo float array, respectively. However, the averages of altimetry, mass, and steric sea level changes have been usually examined over the respective data domains, which are different to one another. Errors arise from this area inconsistency is rarely discussed in the previous studies. Here in this study, an alternative definition of ocean domain is applied for examining sea level budgets, and the results are compared with estimates from different ocean areas. It shows that the impact of area inconsistency is estimated by about 0.3 mm/yr of global trend difference, and averages based on a consistent ocean area yield a closer agreement between altimetry and mass + steric in trend. This contribution would explain some discordances of past sea level budget studies.

Assessing the performance of a foraminifera-based transfer function to estimate sea-level changes in northern Portugal

2011 ◽  
Vol 75 (1) ◽  
pp. 278-287 ◽  
Author(s):  
Eduardo Leorri ◽  
Francisco Fatela ◽  
Alejandro Cearreta ◽  
João Moreno ◽  
Carlos Antunes ◽  
...  
Keyword(s):  
Transfer Function ◽  
Sea Level ◽  
Cross Validation ◽  
Compositional Data ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Concentration Data ◽  
Data Set ◽  
Northern Portugal ◽  
The Impact

AbstractWe assessed the performance of a transfer function model for sea-level studies using salt-marsh foraminifera from two estuaries of northern Portugal. An independent data set of 12 samples and 13 sub-fossil samples from a core were used to evaluate if reconstructions and errors derived from current models are adequate. Initial transfer function models provided very strong results as indicated by cross-validation (component 2; r2 = 0.80–0.82; RMSEP ranged from 10.7 to 12.3 cm) and improved its performance by ca. 10% when sample size reached ca. 50. Results derived using an independent test data set indicate that cross-validation is a very effective approach and produces conservative errors when compared to observed errors. We additionally explored the possible effect of transforming the concentration data into percent in the error estimations by comparing the results obtained based on the use of both concentration and compositional data. Results indicate that this type of transformation does not affect the performance of the transfer function. Results derived from a reconstruction of sub-fossil samples from a core indicate that high-resolution sea-level reconstructions are possible, but show that depositional environments have to be selected carefully in order to minimize the impact of possible taphonomical loss.

Molecular fossils inferring Quaternary sea-level changes

2020 ◽  
Author(s):  
Martina Conti ◽  
Martin Bates ◽  
Natasha Barlow ◽  
Richard Preece ◽  
Kirsty Penkman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
Sea Level Change ◽  
Sea Level Changes ◽  
Primary Producers ◽  
Chlorophyll Pigments ◽  
Molecular Fossils ◽  
Level Change ◽  
Targeted Analysis ◽  
The Impact

<p>Targeted analysis of organic matter in soils and sediments is useful for evaluating past environmental conditions, as specific compounds may be directly linked to organisms and hence to the conditions in which they inhabited the environment.  Variations in molecular fossil distributions have become a powerful tool for understanding changes in palaeoclimate conditions.  This work uses molecular fossils to give an insight into the impact of transgressive events on primary producers inhabiting the studied basin, and hence a more detailed record of sea-level change.</p><p>The cores studied consisted of unconsolidated immature sediments from the mid-late Pleistocene (< 500,000 years) and the Holocene.  Molecular fossils, such as chlorophyll pigments and lipids, exhibit fluctuations as a response to changes in palaeoenvironmental conditions, providing a useful marker for sea-level changes.  Fluctuations in the pigment and <em>n</em>-alkane distribution reflect changes in primary producer activity, while the GDGT-based index of branched and isoprenoid tetraether lipids (BIT) differentiates between terrigenous and marine organic matter inputs.  Lipids were analysed by GC-FID and HPLC-MS while analysis of chlorophyll pigments was carried out using a new UHPLC-DAD method.</p><p>The results from biomarker analyses show excellent time-resolved agreement with previous lithological and ecological studies, but enabled a more sensitive response of different primary producers to changing conditions to be observed.  The molecular fossils were able to detect the onset and cessation of the studied transgressions earlier than it was possible with microfossil evidence.  Linking the pigment and lipid record with more secure dating will enable a more accurate record of Quaternary relative sea-level change.</p>

Steric sea level changes estimated from historical ocean subsurface temperature and salinity analyses

2006 ◽  
Vol 62 (2) ◽  
pp. 155-170 ◽  
Author(s):  
Masayoshi Ishii ◽  
Masahide Kimoto ◽  
Kenji Sakamoto ◽  
Sin-Iti Iwasaki
Keyword(s):  
Sea Level ◽  
Subsurface Temperature ◽  
Sea Level Changes ◽  
Steric Sea Level

scholarly journals An Estimate of Increases in Storm Surge Risk to Property from Sea Level Rise in the First Half of the Twenty-First Century

2010 ◽  
Vol 2 (4) ◽  
pp. 271-293 ◽  
Author(s):  
Ross N. Hoffman ◽  
Peter Dailey ◽  
Susanna Hopsch ◽  
Rui M. Ponte ◽  
Katherine Quinn ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Full Range ◽  
High Tide ◽  
World Ocean ◽  
Sea Level Changes ◽  
Global Signal ◽  
The Impact ◽  
Zip Code

Abstract Sea level is rising as the World Ocean warms and ice caps and glaciers melt. Published estimates based on data from satellite altimeters, beginning in late 1992, suggest that the global mean sea level has been rising on the order of 3 mm yr−1. Local processes, including ocean currents and land motions due to a variety of causes, modulate the global signal spatially and temporally. These local signals can be much larger than the global signal, and especially so on annual or shorter time scales. Even increases on the order of 10 cm in sea level can amplify the already devastating losses that occur when a hurricane-driven storm surge coincides with an astronomical high tide. To quantify the sensitivity of property risk to increasing sea level, changes in expected annual losses to property along the U.S. Gulf and East Coasts are calculated as follows. First, observed trends in sea level rise from tide gauges are extrapolated to the year 2030, and these changes are interpolated to all coastal locations. Then a 10 000-yr catalog of simulated hurricanes is used to define critical wind parameters for each event. These wind parameters then drive a parametric time-evolving storm surge model that accounts for bathymetry, coastal geometry, surface roughness, and the phase of the astronomical tide. The impact of the maximum storm surge height on a comprehensive inventory of commercial and residential property is then calculated, using engineering models that take into account the characteristics of the full range of construction types. Average annual losses projected to the year 2030 are presented for regions and key states and are normalized by aggregate property value on a zip code by zip code basis. Comparisons to the results of a control run reflecting the risk today quantify the change in risk per dollar of property on a percentage basis. Increases in expected losses due to the effect of sea level rise alone vary by region, with increases of 20% or more being common. Further sensitivity tests quantify the impact on the risk of sea level rise plus additional factors, such as changes in hurricane frequency and intensity as a result of rising sea surface temperatures.

Closing the global and regional sea level budgets by combining multi-mission altimetry and GRACE(-FO) data

2020 ◽  
Author(s):  
Bernd Uebbing ◽  
Christina Lück ◽  
Roelof Rietbroek ◽  
Kristin Vielberg ◽  
Jürgen Kusche
Keyword(s):  
Time Series ◽  
Sea Level ◽  
Sea Level Change ◽  
Inversion Method ◽  
Data Sets ◽  
Sea Level Changes ◽  
Steric Sea Level ◽  
Level Change ◽  
Spatial Coverage ◽  
Regional Sea Level

<p>Understanding present day sea level changes and their drivers requires the separation of the total sea level change into individual mass and steric related contributions. Total sea level rise has been observed continuously since 1993 providing a more than 25 year long time series of global and regional sea level variations. However, direct monitoring of ocean mass change has only been done since the start of the Gravity Recovery And Climate Experiment (GRACE) mission in 2002. It ended in 2017 and was succeeded by the follow-on mission (GRACE-FO) in 2018 leaving a gap of about 1 year. In the same time period of GRACE, since the early 2000s, a global array of freely drifting Argo floats samples temperature and salinity profiles of up to 2000m depth which can be converted to steric sea level change.</p><p>By combining altimetry, GRACE(-FO) and Argo data sets it is possible to derive global and regional sea level budgets. The conventional approach is to analyze at least two of the data sets and derive the residual, or compare with the third one. A more recent approach is the global joint inversion method (Rietbroek et al., 2016) which fits forward-modeled spatial fingerprints to a combination of GRACE gravity data and Jason-1/-2 satellite altimetry data. This enables us, additionally, to separate altimetric sea level change into mass contributions from terrestrial hydrology, the melting of land glaciers and the ice-sheets in Greenland and Antarctica as well as contributions from steric sea level changes due to variations in ocean temperature and salinity. It also allows to include a data weighting scheme in the analysis.</p><p>Here, we present global and regional sea level budget results from an updated inversion based on multi-mission altimetry (Jason-1/-2/-3, Envisat, Cryosat-2, Sentinel-3, …) providing better spatial coverage as well as new RL06 GRACE and GRACE-FO data which enables us to extend the time series of individual components of the sea level budget beyond the GRACE era from 2002-04 till 2019-06. The presented sea level budget is closed on global scale with a residual (unexplained) contribution of about 0.1 mm/yr, globally, originating in eddy-active regions. We provide consistent validation of our results against conventionally analyzed altimetry and GRACE data sets where we find agreement on global scales to be better than 0.1 mm/yr but a larger disagreement at regional scales as well as the implications of our results for deriving ocean heat content. We will also provide first results for filling the gap in the sea level budget estimates due to the gap between the GRACE and GRACE-FO missions by additionally incorporating time-variable gravity information from the Swarm mission as well as from Satellite Laser Ranging (SLR) to 5 satellites (Lageos-1/-2, Stella, Starlette, Ajisai).</p>

The Impact of Rapid Sea Level Changes on Recent Azerbaijan Beach Ridges

2007 ◽  
Vol 232 ◽  
pp. 521-527 ◽  
Author(s):  
Joep E. A. Storms ◽  
Salomon B. Kroonenberg
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Beach Ridges ◽  
The Impact

scholarly journals Steric Sea Level Changes from Ocean Reanalyses at Global and Regional Scales

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1987
Author(s):  
Andrea Storto ◽  
Antonio Bonaduce ◽  
Xiangbo Feng ◽  
Chunxue Yang
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
General Circulation ◽  
Climate Projections ◽  
Sea Level Changes ◽  
Steric Sea Level ◽  
Skill Scores ◽  
Ocean Reanalyses ◽  
Recent Climate ◽  
Sea Level Trend

Sea level has risen significantly in the recent decades and is expected to rise further based on recent climate projections. Ocean reanalyses that synthetize information from observing networks, dynamical ocean general circulation models, and atmospheric forcing data offer an attractive way to evaluate sea level trend and variability and partition the causes of such sea level changes at both global and regional scales. Here, we review recent utilization of reanalyses for steric sea level trend investigations. State-of-the-science ocean reanalysis products are then used to further infer steric sea level changes. In particular, we used an ensemble of centennial reanalyses at moderate spatial resolution (between 0.5 × 0.5 and 1 × 1 degree) and an ensemble of eddy-permitting reanalyses to quantify the trends and their uncertainty over the last century and the last two decades, respectively. All the datasets showed good performance in reproducing sea level changes. Centennial reanalyses reveal a 1900–2010 trend of steric sea level equal to 0.47 ± 0.04 mm year−1, in agreement with previous studies, with unprecedented rise since the mid-1990s. During the altimetry era, the latest vintage of reanalyses is shown to outperform the previous ones in terms of skill scores against the independent satellite data. They consistently reproduce global and regional upper ocean steric expansion and the association with climate variability, such as ENSO. However, the mass contribution to the global mean sea level rise is varying with products and its representability needs to be improved, as well as the contribution of deep and abyssal waters to the steric sea level rise. Similarly, high-resolution regional reanalyses for the European seas provide valuable information on sea level trends, their patterns, and their causes.

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