Accuracy of altimeter data in inner and coastal seas

Abstract. We carry out an inter comparison among four different altimeters, Cryosat, Jason2, Jason3, Sentinel-3. This is done checking the altimeter data versus the same wind and wave model results of a given area, the Mediterranean Sea, for one year period. The four datasets are consistent for wind speed, but they show substantial differences for wave heights. The verification of a Sentinel-3 pass close to coast in the Northern Adriatic Sea shows irregular spiky large wave height values close to coast. The problem worsens using high frequency altimeter data.

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Accuracy of altimeter data in inner and coastal seas

Ocean Science ◽

10.5194/os-15-227-2019 ◽

2019 ◽

Vol 15 (2) ◽

pp. 227-233 ◽

Cited By ~ 4

Author(s):

Luigi Cavaleri ◽

Luciana Bertotti ◽

Paolo Pezzutto

Keyword(s):

Wind Speed ◽

High Frequency ◽

Adriatic Sea ◽

Wave Model ◽

Altimeter Data ◽

Data Sets ◽

Northern Adriatic Sea ◽

Large Wave ◽

Northern Adriatic ◽

Wave Heights

Abstract. We carry out an inter-comparison of four different altimeters: Cryosat, Jason-2, Jason-3, and Sentinel-3. This inter-comparison is undertaken by checking the altimeter data against the wind and wave model results of a given area, the Mediterranean Sea, for a 1-year period. The four data sets are consistent for wind speed, but they show substantial differences with respect to wave heights. The verification of a Sentinel-3 pass close to the coast in the northern Adriatic Sea shows irregular, spiky, large, wave height values close to the coast. This problem worsens when using high-frequency altimeter data.

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Impact of the October 2018 Storm Vaia on Coastal Boulders in the Northern Adriatic Sea

Water ◽

10.3390/w11112229 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2229 ◽

Cited By ~ 10

Author(s):

Biolchi ◽

Denamiel ◽

Devoto ◽

Korbar ◽

Macovaz ◽

...

Keyword(s):

Adriatic Sea ◽

Three Dimensional ◽

Deep Understanding ◽

Wave Model ◽

Aerial Survey ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

Multidisciplinary Study ◽

Rocky Coast ◽

Full Force

Boulder detachment from the seafloor and subsequent transport and accumulation along rocky coasts is a complex geomorphological process that requires a deep understanding of submarine and onshore environments. This process is especially interesting in semi-enclosed shallow basins characterized by extreme storms, but without a significant tsunami record. Moreover, the response of boulder deposits located close to the coast to severe storms remains, in terms of accurate displacement measurement, limited due to the need to acquire long-term data such as ongoing monitoring datasets and repeated field surveys. We present a multidisciplinary study that includes inland and submarine surveys carried out to monitor and accurately quantify the recent displacement of coastal boulders accumulated on the southernmost coast of the Premantura (Kamenjak) Promontory (Croatia, northern Adriatic Sea). We identified recent boulder movements using unmanned aerial vehicle digital photogrammetry (UAV-DP). Fourteen boulders were moved by the waves generated by a severe storm, named Vaia, which occurred on 29 October 2018. This storm struck Northeast Italy and the Istrian coasts with its full force. We have reproduced the storm-generated waves using unstructured wave model Simulating WAves Nearshore (SWAN), with a significant wave height of 6.2 m in front of the boulder deposit area. These simulated waves are considered to have a return period of 20 to 30 years. In addition to the aerial survey, an underwater photogrammetric survey was carried out in order to create a three-dimensional (3D) model of the seabed and identify the submarine landforms associated with boulder detachment. The survey highlighted that most of the holes can be considered potholes, while only one detachment shape was identified. The latter is not related to storm Vaia, but to a previous storm. Two boulders are lying on the seabed and the underwater surveys highlighted that these boulders may be beached during future storms. Thus, this is an interesting example of active erosion of the rocky coast in a geologically, geomorphologically, and oceanologically predisposed locality.

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Validation of Surface Current Measurements in the Northern Adriatic Sea from High-Frequency Radars

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2009jtecho680.1 ◽

2010 ◽

Vol 27 (5) ◽

pp. 908-919 ◽

Cited By ~ 35

Author(s):

Simone Cosoli ◽

Andrea Mazzoldi ◽

Miroslav Gačić

Keyword(s):

High Frequency ◽

Adriatic Sea ◽

Surface Current ◽

Broadband Noise ◽

Radial Velocities ◽

Hf Radar ◽

Doppler Spectrum ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

Vector Correlation

Abstract The performances of a shore-based high-frequency (HF) radar network deployed along the coast of the Venice lagoon (northern Adriatic Sea) are discussed based on a comparison with a single bottom-mounted ADCP deployed in the shallow-water area offshore of the lagoon for a 40-day period in August–September 2005. The analyses, carried out using currents representative of the first meter for the HF radars and 2.5 m for the ADCP, gave rms differences of radial currents in the range of 8.7–14.7 cm s−1 (correlation 0.37– 0.82) for the ideal pattern and 8.4–20.5 cm s−1 (correlation 0.14–0.84) for the measured pattern. Good correlation was found between surface current vectors and moored data (scalar correlation up to R = 0.83, vector correlation ρ = 0.78, veering angle 6°). Comparison metrics were improved for the low-passed currents. Angular offsets ranged between +6° and +11°. Differences depended primarily on the geophysical variability within the water column. Bearing offsets also contributed because they lead to comparisons with radial velocities at erroneous angular sectors. Radar performances were severely affected by strong northeasterly wind pulses in their early stages. An increased broadband noise, spread over the entire Doppler spectrum across all ranges to the antennas, masked the Bragg peaks and determined the loss in radar coverage, introducing gross underestimations of both radial velocities and total currents.

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Health status of wild and cultured sea bass in the northern Adriatic Sea

Veterinární Medicína ◽

10.17221/5828-vetmed ◽

2012 ◽

Vol 47 (No. 8) ◽

pp. 222-226 ◽

Cited By ~ 20

Author(s):

R. Čož-Rakovac R ◽

I. Strunjak-Perović ◽

N. Topić Popović ◽

M. Hacmanjek ◽

B. Šimpraga ◽

...

Keyword(s):

Adriatic Sea ◽

Fatty Infiltration ◽

Dicentrarchus Labrax ◽

Sea Bass ◽

Northern Adriatic Sea ◽

Complex Survey ◽

Northern Adriatic ◽

Glucose Levels ◽

Cultured Fish ◽

One Year

A complex survey has been conducted in the northern Adriatic Sea over a period of one year that included comparative parasitological, bacteriological, virological, histological and biochemical studies of the cultured and wild sea bass (Dicentrarchus labrax L.). The results show that parasite infestations were due mainly to ectoparasitic monogenea Diplectanum sp. in both cultured and wild sea bass. Philometra sp. and Lernaea sp. were detected in wild sea bass while Triaenophorus sp. and Eimeria sp. were found in reared sea bass. Bacterial pathogens isolated from both reared and wild sea bass belong to Pseudomonadaceae (Pseudomonas sp., P. fluorescens) and unknown Gram-negative bacteria. Moraxellaceae (Acinetobacter sp.), Vibrionaceae (Shewanella putrefaciens), Enterobacteriaceae (Pantoea agglomerans) and Flavobacterium sp. were isolated from reared fish only. Virological examinations were negative. Histological analysis revealed “fatty liver” (fatty infiltration and degeneration) in the cultured fish. Triglyceride, cholesterol and glucose levels were higher in cultured sea bass (2.55 ± 1.77 mmol/l, 3.68 ± 1.43 mmol/l and 9.97 ± 3.33 mmol/l, respectively) than in wild fish (0.80 ± 0.57 mmol/l, 2.95 ± 0.77 mmol/l and 4.79 ± 3.29 mmol/l, respectively). The present paper contributes to establishing a relationship between disease and pathophysiological conditions in wild and cultured fish.

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Statistical trend analysis and extreme distribution of significant wave height from 1958 to 1999 – an application to the Italian Seas

Ocean Science ◽

10.5194/os-6-525-2010 ◽

2010 ◽

Vol 6 (2) ◽

pp. 525-538 ◽

Cited By ~ 29

Author(s):

G. Martucci ◽

S. Carniel ◽

J. Chiggiato ◽

M. Sclavo ◽

P. Lionello ◽

...

Keyword(s):

Extreme Values ◽

Wave Model ◽

Northern Adriatic Sea ◽

Sea State ◽

Northern Adriatic ◽

Significant Wave ◽

Peak Over Threshold ◽

Wave Heights ◽

Italian Coasts ◽

A Site

Abstract. The study is a statistical analysis of sea states timeseries derived using the wave model WAM forced by the ERA-40 dataset in selected areas near the Italian coasts. For the period 1 January 1958 to 31 December 1999 the analysis yields: (i) the existence of a negative trend in the annual- and winter-averaged sea state heights; (ii) the existence of a turning-point in late 80's in the annual-averaged trend of sea state heights at a site in the Northern Adriatic Sea; (iii) the overall absence of a significant trend in the annual-averaged mean durations of sea states over thresholds; (iv) the assessment of the extreme values on a time-scale of thousand years. The analysis uses two methods to obtain samples of extremes from the independent sea states: the r-largest annual maxima and the peak-over-threshold. The two methods show statistical differences in retrieving the return values and more generally in describing the significant wave field. The r-largest annual maxima method provides more reliable predictions of the extreme values especially for small return periods (<100 years). Finally, the study statistically proves the existence of decadal negative trends in the significant wave heights and by this it conveys useful information on the wave climatology of the Italian seas during the second half of the 20th century.

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Statistical trend analysis and extreme distribution of significant wave height from 1958 to 1999 – an application to the Italian Seas

Ocean Science Discussions ◽

10.5194/osd-6-2005-2009 ◽

2009 ◽

Vol 6 (3) ◽

pp. 2005-2036 ◽

Cited By ~ 5

Author(s):

G. Martucci ◽

S. Carniel ◽

J. Chiggiato ◽

M. Sclavo ◽

P. Lionello ◽

...

Keyword(s):

Extreme Values ◽

Wave Model ◽

Northern Adriatic Sea ◽

Sea State ◽

Northern Adriatic ◽

Significant Wave ◽

Peak Over Threshold ◽

Wave Heights ◽

Italian Coasts ◽

A Site

Abstract. The study is a statistical analysis of sea states timeseries derived using the wave model WAM forced by the ERA-40 dataset in selected areas near the Italian coasts. For the period 1 January 1958 to 31 December 1999 the analysis yields: (i) the existence of a negative trend in the annual- and winter-averaged sea state heights; (ii) the existence of a turning-point in late 70's in the annual-averaged trend of sea state heights at a site in the Northern Adriatic Sea; (iii) the overall absence of a significant trend in the annual-averaged mean durations of sea states over thresholds; (iv) the assessment of the extreme values on a time-scale of thousand years. The analysis uses two methods to obtain samples of extremes from the independent sea states: the r-largest annual maxima and the peak-over-threshold. The two methods show statistical differences in retrieving the return values and more generally in describing the significant wave field. The study shows the existence of decadal negative trends in the significant wave heights and by this it conveys useful information on the wave climatology of the Italian seas during the second half of the 20th century.

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Numerical Investigation of Typhoon Waves Generated by Three Typhoons in the China Sea

10.5194/os-2019-111 ◽

2019 ◽

Author(s):

Qing Shi ◽

Jun Tang ◽

Yongming Shen ◽

Yuxiang Ma

Keyword(s):

Wind Speed ◽

Wind Field ◽

Wave Model ◽

Satellite Observations ◽

Altimeter Data ◽

Correction Coefficient ◽

Wind Fields ◽

China Sea ◽

Wave Heights ◽

Typhoon Waves

Abstract. The typhoon waves generated in the China Sea during the Chan-hom (1509), Linfa (1510) and Nangka (1511) typhoons that occurred in 2015 were numerically investigated. The wave model was based on the a third generation spectral wind-wave model SWAN, in which the wind fields for driving waves were derived from the ERA-interim (ECMWF), CFSv2 (The NCEP Climate Forecast System Version 2) and CCMP (Cross-Calibrated Multi-Platform) datasets. The numerical results were validated using buoy data and satellite observation data. The simulation results under the three types of wind fields were in good agreement with the observed data. The CCMP wind data was the best in simulating waves overall, and the wind speeds pertaining to ERA and CCMP were notably smaller than those observed near the typhoon centre. The Holland wind model was used to revise and optimize the wind speed pertaining to the CCMP near the typhoon centre, and the wind speed correction coefficient, correction formula and corresponding parameters were determined. Based on these findings, the CCMP and CCMP/Holland blended wind fields were used to simulate the typhoon waves generated during the Meranti (1614), Rai (1615) and Malakas (1616) typhoons that occurred in September 2016. A comparison between the simulated wave heights and those obtained from the Jason-2 altimeter data indicated that all correlation coefficients between the simulated values and the satellite observations were greater than 0.75. The blended wind field was better overall in simulating the wave heights. The simulated maximum wave heights were more similar to the satellite observations, and the root mean square error of the blended wind field was 0.223 m lower than that of the CCMP. The results demonstrated that the CCMP wind-driven SWAN model could appropriately simulate the typhoon waves generated by three typhoons in China Sea, and the use of the CCMP/Holland blended wind field could effectively improve the accuracy of typhoon wave simulations.

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