Spectral analysis of sea level during the altimetry era, and evidence for GIA and glacial melting fingerprints

2016 ◽  
Vol 143 ◽  
pp. 34-49 ◽  
Author(s):  
G. Spada ◽  
G. Galassi
Keyword(s):  
Spectral Analysis ◽  
Sea Level ◽  
Glacial Melting

scholarly journals Interannual variability of atmospheric Nitrous Oxide (N2O)

MAUSAM ◽  
2021 ◽  
Vol 51 (2) ◽  
pp. 163-168
Author(s):  
R. P. KANE
Keyword(s):  
Growth Rate ◽  
Nitrous Oxide ◽  
Spectral Analysis ◽  
Sea Level ◽  
Atmospheric Pressure ◽  
Pressure Difference ◽  
Southern Oscillation ◽  
Low Latitude ◽  
Maximum Entropy Spectral Analysis ◽  
Oscillation Phenomenon

The 12-monthly running means of N2O measured at seven locations during 1977-91 were used for obtaining the yearly percentage growth rate series (4 values per year, centered 3 months apart), which were subjected to MESA (Maximum Entropy Spectral Analysis). The spectra revealed significant QBO and QTO (Quasi-biennial and Quasi-triennial oscillations) with QBO periods in the range (2.04-2.38) years and QTO periods near 4.0 years. These do not resemble the QBO of 2.58 years of the 50 hPa low latitude wnal wind but do resemble the QBO of 2.31 years and the 4.1 year periods of the Southern oscillation phenomenon, represented by Tahiti minus Darwin sea level atmospheric pressure difference (T-D).

A long-term trend and temporal fluctuations of the sea level at the Polish Baltic coast

2011 ◽  
Vol 40 (2) ◽  
Author(s):  
Bernard Wiśniewski ◽  
Tomasz Wolski ◽  
Stanisław Musielak
Keyword(s):  
Spectral Analysis ◽  
Sea Level ◽  
Data Series ◽  
Sea Level Changes ◽  
Mean Sea Level ◽  
Term Trend ◽  
Baltic Coast ◽  
Long Term Trend ◽  
Linear Trends

AbstractThe analysis of sea level record series along the Polish coast is presented. The main aim was to identify linear trends in the sea level changes at the coastal (Świnoujście, Kołobrzeg, Ustka, Łeba, Władysławowo, Hel, Gdynia, Gdańsk), lagoonal (Trzebież, Tokmicko) and riverine (Szczecin) gauge stations. The analysis showed individual coastal stations to differ in the rate of sea level changes. During 60 years of continuous observations (1947–2006), the differences varied from 1.0 (the western part of the coast) to 2.5 mm year−1 (the eastern part of the coast). The longest, more than 100-yr-long data series showed the sea level rise in Świnoujście and Kołobrzeg to be about 0.5 mm year−1; 1.57 mm year−1 being revealed in Gdańsk. Spectral analysis applied to the data showed numerous fluctuations and cyclicity in changes of the annual mean sea level at the Polish coast. A distinct, major 3-year cycle was revealed. In addition, three secondary cycles of 4.6, 6.7, and 8.6 years were present in the data, more or less clearly identifiable at individual stations.

Optimum microfossil sequences and cyclic sediment patterns in Early Cretaceous pelagic strata

1993 ◽  
Vol 30 (2) ◽  
pp. 391-411 ◽  
Author(s):  
Felix M. Gradstein ◽  
Zehui Huang ◽  
Inger L. Kristiansen ◽  
James G. Ogg
Keyword(s):  
Spectral Analysis ◽  
Atlantic Ocean ◽  
Sea Level ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Planktonic Foraminifera ◽  
Power Spectra ◽  
Calcareous Nannofossils ◽  
Data Set ◽  
Sea Level Fluctuations

Three sequencing methods were used to calculate the most likely biozonation and the periodicity of sedimentary cycles in Lower Cretaceous pelagic strata of the Atlantic and Indian oceans.A database was built of 378 first and last stratigraphic occurrences of calcareous nannofossils, dinocysts, foraminifers, and geomagnetic reversals in highest Jurassic through Lower Cretaceous deep marine strata at 10 Atlantic Ocean and 3 Indian Ocean drilling sites. There are 135 different events in total, about one third of which are unique to either ocean. Using the complete data set, the quantitative stratigraphy methods STRATCOR and RASC calculated closely comparable optimum sequences of average first- and last-occurrence positions. The preferred zonal solution, based on the STRATCOR method, includes 56 events, each of which occurs at three or more sites. The events comprise 6 geomagnetic reversals, 25 nannofossils, 5 planktonic foraminifera, 8 benthic foraminifera, and 12 dinocysts occurrences. Nine assemblage zones have been recognized of Tithonian through Albian age. All but 2 of 18 nannofossil events in the Atlantic Ocean optimum sequence were reported in the same stratigraphic order in a standard Mesozoic nannofossil zonation.Our quantitative examination, using Walsh spectral analysis, of the Lower Cretaceous cyclic sequences at three Deep Sea Drilling Project (DSDP) sites in the Atlantic Ocean generally supports the hypothesis that they are the product of cyclic climatic changes controlled by the Milankovitch orbital cycles. The peaks in the power spectra usually can be related to obliquity and precession cycles; some peaks seem to correspond to the eccentricity cycle. Obliquity seems to be the most important and persistent orbital element responsible for cyclic sedimentation in the Early Cretaceous Atlantic Ocean.The actual pelagic sedimentation rates were calculated for some cores using the results of spectral analysis. The correlation of the actual pelagic sedimentation rate with cyclic patterns and the occurrence of calcareous turbidites indicate that the changes in cycle pattern are the reflection of changes in the oceanographic setting. The changes in oceanographic setting are related to relative-sea-level fluctuations. The intervals dominated by laminated limestone were deposited during higher sea-level periods.

scholarly journals Characterisation of low-frequency sea level oscillations in the Mediterranean sea

2019 ◽  
pp. 121-133
Author(s):  
Vesna Bertoncelj ◽  
Matjaž Ličer ◽  
Dušan Žagar ◽  
Davide Bonaldo
Keyword(s):  
Spectral Analysis ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Mediterranean Basin ◽  
Adriatic Sea ◽  
Low Frequency ◽  
Storm Event ◽  
Sea Level Oscillations ◽  
The Mediterranean ◽  
The Mediterranean Basin

Implementing adequate defences for low-lying coastal area against coastal flooding requires thorough knowledge of all potential influences leading to increased sea levels, including low-frequency sea level oscillations. We present and describe several methods applicable for the analysis of low-frequency sea level oscillations in the Mediterranean Sea: wavelet analysis, spectral analysis, moving-periodogram analysis, and rotary spectral analysis. These methods were applied for characterisation of subinertial sea level oscillations with periods greater of the period of inertial oscillation (18 hours in the Northern Adriatic Sea) on measured sea surface elevations and current velocities in the Mediterranean Sea. Preliminary analysis was performed on observations of a storm event in the Adriatic Sea at the end of January and the beginning of February 2014, revealing a peak in the frequency spectrum in the frequency band between 0.3−0.4 day−1. Further analysis was done on long-term tide gauge measurements available for 62 stations in the Mediterranean basin. The application of the selected methods provided a preliminary set of seasonal occurrences and durations of subinertial oscillation. This sets the ground for further investigation into the propagation of low-frequency sea level oscillations throughout the Mediterranean basin and for characterisation of the mechanisms triggering the process, including with regard to climate change.

scholarly journals A point-wise least squares spectral analysis (LSSA) of the Caspian Sea level fluctuations, using TOPEX/Poseidon and Jason-1 observations

2013 ◽  
Vol 51 (5) ◽  
pp. 858-873 ◽  
Author(s):  
M.A. Sharifi ◽  
E. Forootan ◽  
M. Nikkhoo ◽  
J.L. Awange ◽  
M. Najafi-Alamdari
Keyword(s):  
Spectral Analysis ◽  
Least Squares ◽  
Sea Level ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Sea Level Fluctuations

'Clean' spectral analysis of long-term sea-level changes

Terra Nova ◽  
1990 ◽  
Vol 2 (2) ◽  
pp. 138-141 ◽  
Author(s):  
J.G. Negi ◽  
R.K. Tiwari ◽  
K.N.N. Rao
Keyword(s):  
Spectral Analysis ◽  
Sea Level ◽  
Sea Level Changes

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

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