scholarly journals More confounders at global and decadal scales in detecting recent sea level accelerations

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
H. Bâki Iz
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Almost Periodic ◽  
Altimetry Data ◽  
Tide Gauge Data ◽  
Gauge Data ◽  
Close Range ◽  
Globally Distributed ◽  
Satellite Altimetry Data

AbstractThe residuals of 27 globally distributed long tide gauge recordswere scrutinized after removing the globally compounding effect of the periodic lunar node tides and almost periodic solar radiation’s sub and superharmonics from the tide gauge data. The spectral analysis of the residuals revealed additional unmodeled periodicities at decadal scales, 19 of which are within the close range of 12–14 years, at 27 tide gauge stations. The amplitudes of the periodicitieswere subsequently estimated for the spectrally detected periods and they were found to be statistically significant (p «0.05) for 18 out of 27 globally distributed tide gauge stations. It was shown that the estimated amplitudes at different localities may have biased the outcome of all the previous studies based on tide gauge or satellite altimetry data that did not account for these periodicities, within the range −0.5 – 0.5 mm/yr., acting as another confounder in detecting 21st century sea level rise.

scholarly journals Sea level accelerations at globally distributed tide gauge stations during the satellite altimetry era

2018 ◽  
Vol 8 (1) ◽  
pp. 130-135 ◽  
Author(s):  
H. Bâki Iz ◽  
C. K. Shum ◽  
C. Y. Kuo
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Tide Gauge Data ◽  
Trend Model ◽  
Gauge Data ◽  
Sea Level Variations ◽  
Global Mean Sea Level ◽  
Globally Distributed ◽  
Global Mean

Abstract This observational study reports that several globally distributed tide gauge stations exhibit a propensity of statistically significant sea level accelerations during the satellite altimetry era. However, the magnitudes of the estimated tide gauge accelerations during this period are systematically and noticeably smaller than the global mean sea level acceleration reported by recent analyses of satellite altimetry. The differences are likely to be caused by the interannual, decadal and interdecadal sea level variations, which are modeled using a broken trend model with overlapping harmonics in the analyses of tide gauge data but omitted in the analysis of satellite altimetry.

scholarly journals Comparing satellite altimetry and tide gauges observations in the Mediterranean Sea within the framework of singular spectrum analysis

MAUSAM ◽  
2021 ◽  
Vol 71 (2) ◽  
pp. 187-198
Author(s):  
HADDAD MAHDI ◽  
TAIBI HEBIB ◽  
MOKRANE MOUSTAFA ◽  
HAMMOUMI HOUSSEYN
Keyword(s):  
Sea Level ◽  
Spectrum Analysis ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Singular Spectrum Analysis ◽  
Altimetry Data ◽  
Tide Gauges ◽  
The Mediterranean ◽  
Satellite Altimetry Data

By considering time series from satellite altimetry and tide gauges that extend back to 1993, Singular Spectrum Analysis (SSA) is applied to investigate and compare the non linear trends of the sea level along the Mediterranean coasts. The major issue of this comparison is to show if the satellite altimetry data could be representative of the local sea level as observed by tide gauges.   The results indicate that the local trends estimated from an in-situ tide gauge and satellite altimetry data show nearly identical positive rates over the period from 1993 to 2017. The differences between the estimated rates of sea level change from in-situ tide gauge and satellite measurements vary, in absolute value, from 0.18 to 4.29 mm/year with an average of 1.55 mm/year.   This result is sufficient to admit, if necessary, on the one hand, the complementarily of the two measurement techniques (satellite altimetry and tide gauges) and, on the other hand, the rise in sea level near the Mediterranean coastal areas.

Sea level change in the Gulf of Thailand from GPS-corrected tide gauge data and multi-satellite altimetry

2011 ◽  
Vol 76 (3-4) ◽  
pp. 137-151 ◽  
Author(s):  
Itthi Trisirisatayawong ◽  
Marc Naeije ◽  
Wim Simons ◽  
Luciana Fenoglio-Marc
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Sea Level Change ◽  
Gulf Of Thailand ◽  
Tide Gauge Data ◽  
Level Change ◽  
Gauge Data ◽  
The Gulf Of Thailand

scholarly journals Sea Level Fusion of Satellite Altimetry and Tide Gauge Data by Deep Learning in the Mediterranean Sea

2021 ◽  
Vol 13 (5) ◽  
pp. 908
Author(s):  
Lianjun Yang ◽  
Taoyong Jin ◽  
Xianwen Gao ◽  
Hanjiang Wen ◽  
Tilo Schöne ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
The Other ◽  
Tide Gauge Data ◽  
Sea Levels ◽  
Sea Level Anomalies ◽  
Gauge Data ◽  
The Mediterranean

Satellite altimetry and tide gauges are the two main techniques used to measure sea level. Due to the limitations of satellite altimetry, a high-quality unified sea level model from coast to open ocean has traditionally been difficult to achieve. This study proposes a fusion approach of altimetry and tide gauge data based on a deep belief network (DBN) method. Taking the Mediterranean Sea as the case study area, a progressive three-step experiment was designed to compare the fused sea level anomalies from the DBN method with those from the inverse distance weighted (IDW) method, the kriging (KRG) method and the curvature continuous splines in tension (CCS) method for different cases. The results show that the fusion precision varies with the methods and the input measurements. The precision of the DBN method is better than that of the other three methods in most schemes and is reduced by approximately 20% when the limited altimetry along-track data and in-situ tide gauge data are used. In addition, the distribution of satellite altimetry data and tide gauge data has a large effect on the other three methods but less impact on the DBN model. Furthermore, the sea level anomalies in the Mediterranean Sea with a spatial resolution of 0.25° × 0.25° generated by the DBN model contain more spatial distribution information than others, which means the DBN can be applied as a more feasible and robust way to fuse these two kinds of sea levels.

scholarly journals Analisa Sea Level Rise Dari Data Satelit Altimetri Topex/Poseidon, Jason-1 Dan Jason-2 Di Perairan Laut Pulau Jawa Periode 2000 – 2010

2016 ◽  
Vol 2 (02) ◽  
pp. 65
Author(s):  
Hastho Wuriatmo ◽  
Sorja Koesuma ◽  
Mohtar Yunianto
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Sea Water ◽  
Tide Gauge ◽  
European Space Agency ◽  
South Coast ◽  
Altimetry Data ◽  
Space Agency ◽  
Satellite Altimetry Data

<span>It has been conducted a research about sea level rise (SLR) in surrounding Jawa island by using <span>satellite altimetry data Topex/Poseidon, Jason-1 dan Jason-2 for period 2000 <span>– <span>2010. Satellite <span>altimetry is satellite which specially design for measuring dynamics of sea water. Those <span>satellite lauched firstly in 1992 incorporation between <span><em>National Aeronautics and Space </em><span><em>Administration </em><span>(<span><em>NASA</em><span>) dan European Space Agency (ESA). There are six locations for <span>measuring SLR i.e. Jakarta, Semarang, Surabaya, Pangandaran, Jogjakarta dan Prigi. We chose<br /><span>locations based on alongtrack of satellite and near the big cities in Jawa island with dimension <span>area around 0.5<span>o<span>x0.5<span>o <span>degrees. We found SLR rate for Jakarta (2.5 ± 0.24 mm/yr), Semarang <span>(2.16 ± 0.20 mm/yr), Surabaya (2.72 ± 0.19 mm/yr), Pangandaran (0.71 ± 0.33 mm/yr), <span>Jogjakarta (0.91 ± 0.38 mm/yr) and Prigi (1.3 ± 0.38 mm/yr). The average SLR rate for North <span>coast is (2.46 ± 0.21 mm/yr) and for South coast (0.97 ± 0.36 mm/yr). This results are well<br /><span>correlated with data from tide gauge stations.</span></span></span></span></span></span></span></span></span></span></span><br /></span></span></span></span></span></span></span></span></span></span></span>

scholarly journals An Attempt to Observe Vertical Land Motion along the Norwegian Coast by CryoSat-2 and Tide Gauges

2019 ◽  
Vol 11 (7) ◽  
pp. 744 ◽  
Author(s):  
Martina Idžanović ◽  
Christian Gerlach ◽  
Kristian Breili ◽  
Ole Andersen
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Ice Sheets ◽  
Tide Gauges ◽  
Tide Gauge Data ◽  
Norwegian Coast ◽  
Vertical Land Motion ◽  
Gauge Data

Present-day climate-change-related ice-melting induces elastic glacial isostatic adjustment (GIA) effects, while paleo-GIA effects describe the ongoing viscous response to the melting of late-Pleistocene ice sheets. The unloading initiated an uplift of the crust close to the centers of former ice sheets. Today, vertical land motion (VLM) rates in Fennoscandia reach values up to around 10 mm/year and are dominated by GIA. Uplift signals from GIA can be computed by solving the sea-level equation (SLE), S ˙ = N ˙ − U ˙ . All three quantities can also be determined from geodetic observations: relative sea-level variations ( S ˙ ) are observed by means of tide gauges, while rates of absolute sea-level change ( N ˙ ) can be observed by satellite altimetry; rates of VLM ( U ˙ ) can be determined by GPS (Global Positioning System). Based on the SLE, U ˙ can be derived by combining sea-surface measurements from satellite altimetry and relative sea-level records from tide gauges. In the present study, we have combined 7.5 years of CryoSat-2 satellite altimetry and tide-gauge data to estimate linear VLM rates at 20 tide gauges along the Norwegian coast. Thereby, we made use of monthly averaged tide-gauge data from PSMSL (Permanent Service for Mean Sea Level) and a high-frequency tide-gauge data set with 10-min sampling rate from NMA (Norwegian Mapping Authority). To validate our VLM estimates, we have compared them with the independent semi-empirical land-uplift model NKG2016LU_abs for the Nordic-Baltic region, which is based on GPS, levelling, and geodynamical modeling. Estimated VLM rates from 1 Hz CryoSat-2 and high-frequency tide-gauge data reflect well the amplitude of coastal VLM as provided by NKG2016LU_abs. We find a coastal average of 2.4 mm/year (average over all tide gauges), while NKG2016LU_abs suggests 2.8 mm/year; the spatial correlation is 0.58.

Sign in / Sign up

Export Citation Format

Share Document