scholarly journals Improved satellite altimeter mapped sea level anomalies in the Mediterranean Sea: A comparison with tide gauges

2015 ◽  
Vol 56 (4) ◽  
pp. 596-604 ◽  
Author(s):  
Marta Marcos ◽  
Ananda Pascual ◽  
Isabelle Pujol
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Tide Gauges ◽  
Satellite Altimeter ◽  
Sea Level Anomalies ◽  
The Mediterranean

scholarly journals The effect of cyclones crossing the Mediterranean region on sea level anomalies at the Mediterranean Sea coast

2019 ◽  
Author(s):  
Piero Lionello ◽  
Dario Conte ◽  
Marco Reale
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Eastern Mediterranean ◽  
Storm Track ◽  
Western Mediterranean ◽  
Residual Water ◽  
Positive Anomaly ◽  
Western Basin ◽  
Sea Level Anomalies ◽  
The Mediterranean

Abstract. Large positive and negative sea level anomalies at the coast of the Mediterranean Sea are linked to intensity and position of cyclones moving along the Mediterranean storm track, with dynamics involving different factors. This analysis is based on a model hindcast and considers nine coastal stations, which are representative of sea level anomalies with different magnitude and characteristics. When a shallow water fetch is present, the wind around the cyclone center is the main cause of sea level positive and negative anomalies, depending on its onshore or offshore direction. The inverse barometer effect produces a positive anomaly at the coast near the cyclone pressure minimum and a negative anomaly at the opposite side of the Mediterranean Sea, because a cross-basin mean sea level pressure gradient is associated to the presence of a cyclone. Further, at some stations, negative sea level anomalies are reinforced by a residual water mass redistribution within the basin, which is associated with a transient response to the atmospheric pressure forcing. Though the link between presence of a cyclone in the Mediterranean has comparable importance for positive and negative anomalies, the relation between cyclone position and intensity is stronger for the magnitude of positive events. Area of cyclogenesis, track of the central minimum and position at the time of the event differ depending on the location where the sea level anomaly occurs and on its sign. The western Mediterranean is the main cyclogenesis area for both positive and negative anomalies, overall. Atlantic cyclones mainly produce positive sea level anomalies in the western basin. At the easternmost stations, positive anomalies are caused by Cyclogenesis in the Eastern Mediterranean. North Africa cyclogeneses are a major source of positive anomalies at the central African coast and negative anomalies at the eastern Mediterranean and North Aegean coast.

The new Mediterranean Sea analysis and forecasting system including tides: description and validation

2021 ◽  
Author(s):  
Emanuela Clementi ◽  
Anna Chiara Goglio ◽  
Ali Aydogdu ◽  
Jenny Pistoia ◽  
Romain Escudier ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Initial Conditions ◽  
Physical Parameters ◽  
Tide Gauges ◽  
Tidal Model ◽  
Forecasting System ◽  
The Mediterranean

<p>The Mediterranean Analysis and Forecasting System operationally produces analyses and 10 days forecasts of the main physical parameters for the entire Mediterranean Sea and its Atlantic Ocean adjacent areas in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS).</p><p>The system is composed by the hydrodynamic model NEMO (Nucleus for European Modelling of the Ocean) 2-way coupled with the third-generation wave model WW3 (WaveWatchIII) and forced by ECMWF (European Centre for Medium-range Weather Forecasts) atmospheric fields. The forecast initial conditions are produced by the OceanVar, a 3D variational data assimilation system which daily assimilates Sea Level Anomaly, vertical profiles of Temperature and Salinity from ARGO and XBT (upon availbility) observations. Moreover a heat flux correction using satellite SST is imposed.</p><p>The system has been recently upgraded by including tidal waves, so that the tidal potential is calculated across the domain for the Mediterranean Sea 8 major constituents: M2, S2, N2, K2, K1, O1, P1, Q1. In addition, tidal forcing is applied along the lateral boundaries in the Atlantic Ocean by means of tidal elevation estimated using the FES2014 global tidal model and tidal currents evaluated using TUGO (Toulouse Unstructured Grid Ocean) model. Moreover the data assimilation scheme now accounts for the tidal signal in the altimeter tracks.</p><p>The system has been validated comparing model results with satellite and in situ observations. A specific harmonic analysis has been performed comparing model sea level amplitudes and phases with respect to: tide gauges, TPXO global tidal model and literature, showing an overall good skill of all the considered tidal constituents. Moreover the ability of the system to predict sea level has been evaluated comparing the model solutions with respect to tide gauges in areas where recent extreme events occurred such as Venice Lagoon “Acqua Alta” in November 2019, Western Mediterranean Sea during Gloria storm in January 2020, Ionian Sea during Medicane Ianos in September 2020.</p>

Estimating Vertical Land Motion in Northern Adriatic Sea with Coastal Altimetry and In Situ Observations

2020 ◽  
Author(s):  
Francesco De Biasio ◽  
Stefano Vignudelli ◽  
Giorgio Baldin
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Coastal Zone ◽  
Satellite Altimetry ◽  
Data Sets ◽  
Tide Gauges ◽  
The Mediterranean

<p align="justify"><span>The European Space Agency, in the framework of the Sea Level Climate Change Initiative (SL_CCI), is developing consistent and long-term satellite-based data-sets to study climate-scale variations of sea level globally and in the coastal zone. Two altimetry data-sets were recently produced. The first product is generated over a grid of 0.25x0.25 degrees, merging and homogenizing the various satellite altimetry missions. The second product that is still experimental is along track over a grid of 0.35 km. An operational production of climate-oriented altimeter sea level products has just started in the framework of the European Copernicus Climate Change Service (C3S) and a daily-mean product is now available over a grid of 0.125x0.125 degrees covering the global ocean since 1993 to present.</span></p><p align="justify"><span>We made a comparison of the SL_CCI satellite altimetry dataset with sea level time series at selected tide gauges in the Mediterranean Sea, focusing on Venice and Trieste. There, the coast is densely covered by civil settlements and industrial areas with a strongly rooted seaside tourism, and tides and storm-related surges reach higher levels than in most of the Mediterranean Sea, causing damages and casualties as in the recent storm of November 12th, 2019: the second higher water registered in Venice since 1872. Moreover, in the Venice area the ground displacements exhibit clear negative trends which deepen the effects of the absolute sea level rise.</span></p><p align="justify"><span>Several authors have pointed out the synergy between satellite altimetry and tide gauges to corroborate evidences of ground displacements. Our contribution aims at understanding the role played by subsidence, estimated by the diffence between coastal altimetry and in situ measurements, on the local sea level rise. A partial validation of these estimates has been made against GPS-derived values, in order to distinguish the contributions of subsidence and eustatism. This work will contribute to identify problems and challenges to extend the sea level climate record to the coastal zone with quality comparable to the open ocean, and also to assess the suitability of altimeter-derived absolute sea levels as a tool to estimate subsidence from tide gauge measurement in places where permanent GPS receivers are not available.</span></p>

scholarly journals Sea-level variability in the Mediterranean Sea from altimetry and tide gauges

2016 ◽  
Vol 47 (9-10) ◽  
pp. 2851-2866 ◽  
Author(s):  
A. Bonaduce ◽  
N. Pinardi ◽  
P. Oddo ◽  
G. Spada ◽  
G. Larnicol
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Tide Gauges ◽  
Sea Level Variability ◽  
The Mediterranean

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 The effect of cyclones crossing the Mediterranean region on sea level anomalies on the Mediterranean Sea coast

2019 ◽  
Vol 19 (7) ◽  
pp. 1541-1564 ◽  
Author(s):  
Piero Lionello ◽  
Dario Conte ◽  
Marco Reale
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Eastern Mediterranean ◽  
Storm Track ◽  
Western Mediterranean ◽  
Residual Water ◽  
Positive Anomaly ◽  
Western Basin ◽  
Sea Level Anomalies ◽  
The Mediterranean

Abstract. Large positive and negative sea level anomalies on the coast of the Mediterranean Sea are linked to intensity and position of cyclones moving along the Mediterranean storm track with dynamics involving different factors. This analysis is based on a model hindcast and considers nine coastal stations, which are representative of sea level anomalies with different magnitudes and characteristics. When a shallow water fetch is present, the wind around the cyclone centre is the main cause of positive and negative sea level anomalies, depending on its onshore or offshore direction. The inverse barometer effect produces a positive anomaly on the coast near the cyclone pressure minimum and a negative anomaly at the opposite side of the Mediterranean Sea. The latter is caused by the cross-basin mean sea level pressure gradient that is associated with the presence of a cyclone. This often coincides with the presence of an anticyclone above the station, which causes a local negative inverse barometer effect. Further, at some stations, negative sea level anomalies are reinforced by a residual water mass redistribution within the basin, which is associated with a transient response to the atmospheric pressure forcing. Though the link with the presence of a cyclone in the Mediterranean has comparable importance for positive and negative anomalies, the relation between cyclone position and intensity is stronger for the magnitude of positive events. The area of cyclogenesis, track of the central minimum and position at the time of the event differ depending on the location the sea level anomaly occurs and on its sign. The western Mediterranean is the main cyclogenesis area for both positive and negative anomalies overall. Atlantic cyclones mainly produce positive sea level anomalies in the western basin. At the easternmost stations, positive anomalies are caused by cyclogenesis in the eastern Mediterranean. North African cyclogenesis is a major source of positive anomalies on the central African coast and negative anomalies on the eastern Mediterranean and northern Aegean coasts.

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