Collinear and cross-over adjustment of Geosat ERM and Seasat altimeter data in the Mediterranean Sea

1993 ◽  
Vol 14 (4-5) ◽  
pp. 449-459 ◽  
Author(s):  
P. Knudsen ◽  
M. Brovelli
Keyword(s):  
Mediterranean Sea ◽  
Altimeter Data ◽  
The Mediterranean

scholarly journals On the mesoscale monitoring capability of Argo floats in the Mediterranean Sea

2016 ◽  
Author(s):  
Antonio Sánchez-Román ◽  
Simón Ruiz ◽  
Ananda Pascual ◽  
Baptiste Mourre ◽  
Stéphanie Guinehut
Keyword(s):  
Mediterranean Sea ◽  
Large Scale ◽  
Spatial Scales ◽  
Altimeter Data ◽  
Simulation Experiments ◽  
Argo Data ◽  
Sea Level Anomalies ◽  
The Mediterranean ◽  
Observing System Simulation Experiment ◽  
Initial Objective

Abstract. In this work an Observing System Simulation Experiment (OSSE) approach is used to investigate the Argo array spatial sampling necessary in the Mediterranean Sea to recover the mesoscale signal as seen by altimetry. The monitoring of the mesoscale features is not an initial objective of the Argo network. However, it is an interesting question in the perspective of future network extensions in order to improve the ocean state estimates. A quality assessment of the performances of the altimeter product is carried out to quantify the differences between Argo and altimetry needed to conduct the simulation experiments. The method used here to evaluate the altimeter data is based on the comparison of Sea Level Anomalies (SLA) from altimetry and Dynamic Height Anomalies (DHA) referred to both 400 and 900 dbar computed from the in-situ Argo network. A standard deviation of the differences between SLA and DHA of 4.92 cm is obtained when comparing altimetry and Argo data referred to 400 dbar. The simulation experiments show that a configuration similar to the current Argo array in the Mediterranean (with a spatial resolution of 2° × 2°) is only able to recover the large-scale signals of the basin. On the contrary, the SLA field reconstructed from a 0.75° x 0.75° Argo network can retrieve most of the mesoscale signal. Such an Argo array of around 450 floats in the Mediterranean Sea would be enough to recover the SLA field with an RMSE of 3 cm for spatial scales higher than 150 km, similar to those captured by the altimetry.

scholarly journals Analysis of Wave Height Variability Using Altimeter Measurements: Application to the Mediterranean Sea

2007 ◽  
Vol 24 (12) ◽  
pp. 2078-2092 ◽  
Author(s):  
Pierre Queffeulou ◽  
Abderrahim Bentamy
Keyword(s):  
Mediterranean Sea ◽  
Interannual Variability ◽  
Wave Height ◽  
Measurement Data ◽  
Altimeter Data ◽  
Mean Values ◽  
The Mediterranean ◽  
Standard Deviations ◽  
Wave Models ◽  
Ocean Topography

Abstract Altimeter significant wave height (SWH) measurement data from six satellite missions covering 14 yr were analyzed over the Mediterranean Sea. First, data correction and screening were performed using the same method for the six altimeters [European Remote Sensing Satellites (ERS-1 and ERS-2), Ocean Topography Experiment (TOPEX), Geosat Follow-On, Jason, and Environmental Satellite (Envisat)]. The data from the TOPEX and Jason missions enabled the construction of seasonal maps of along-track SWH mean values and standard deviations. These reveal the regional short-scale sea state features associated with the specific meteorological patterns of the various geographical basins. Time series of monthly SWH mean values and standard deviations from each satellite and over the whole Mediterranean Sea were calculated and seen to be in good agreement, thus demonstrating interannual variability. The six altimeter missions used together enable the investigation of the monthly annual cycle at the short scales of the various subbasins. Significant differences are observed between the western and eastern parts of the Mediterranean Sea. The annual SWH cycle changes in both shape and amplitude depending on the subbasin. Analysis of the seasonal interannual variability confirms the existence of some degree of independence between the subbasins. Thanks to multisatellite missions and homogeneous corrections of the altimeter data, SWH time and space characteristics were able to be obtained at regional short scales. These results are independent of numerical wind and wave models. This method can be applied to any geographical region.

scholarly journals Assimilation of radar altimeter data in numerical wave models: an impact study in two different wave climate regions

2007 ◽  
Vol 25 (3) ◽  
pp. 581-595 ◽  
Author(s):  
G. Emmanouil ◽  
G. Galanis ◽  
G. Kallos ◽  
L. A. Breivik ◽  
H. Heiberg ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Mediterranean Sea ◽  
European Space Agency ◽  
Wave Climate ◽  
Altimeter Data ◽  
Radar Altimeter ◽  
The Indian Ocean ◽  
Numerical Wave ◽  
The Mediterranean ◽  
Wave Models

Abstract. An operational assimilation system incorporating significant wave height observations in high resolution numerical wave models is studied and evaluated. In particular, altimeter satellite data provided by the European Space Agency (ESA-ENVISAT) are assimilated in the wave model WAM which operates in two different wave climate areas: the Mediterranean Sea and the Indian Ocean. The first is a wind-sea dominated area while in the second, swell is the principal part of the sea state, a fact that seriously affects the performance of the assimilation scheme. A detailed study of the different impact is presented and the resulting forecasts are evaluated against available buoy and satellite observations. The corresponding results show a considerable improvement in wave forecasting for the Indian Ocean while in the Mediterranean Sea the assimilation impact is restricted to isolated areas.

Use of Numerical Wind-Wave Models for Assessment of the Offshore Wave Energy Resource

1997 ◽  
Vol 119 (3) ◽  
pp. 184-190 ◽  
Author(s):  
M. T. Pontes ◽  
S. Barstow ◽  
L. Bertotti ◽  
L. Cavaleri ◽  
H. Oliveira-Pires
Keyword(s):  
Mediterranean Sea ◽  
North Atlantic ◽  
Wave Energy ◽  
Wind Wave ◽  
Energy Resource ◽  
Altimeter Data ◽  
The North ◽  
The North Atlantic ◽  
The Mediterranean ◽  
Wave Models

In the last two decades the performance of numerical wind-wave models has improved considerably. Several models have been routinely producing good quality wave estimates globally since the mid-1980s. The verifications of wind-wave models have mainly focused on the evaluation of the error of the significant wave height Hs estimates. However, for wave energy purposes, the main parameters to be assessed are the wave power Pw and the mean (energy) period Te. Since Pw is proportional to Hs2 Tc, its expected error is much larger than for the single-wave parameters. This paper summarizes the intercomparison of two wind-wave models against buoy data in the North Atlantic and the Mediterranean Sea to select the most suitable one for the construction of an Atlas of the wave energy resource in European waters. A full verification in the two basins of the selected model—the WAM model implemented in the routine operation of the European Centre for Medium-Range Weather Forecasts—was then performed against buoy and satellite altimeter data. It was found that the WAM model accuracy is very good for offshore locations in the North Atlantic; but for the Mediterranean Sea the results are much less accurate, probably due to a lower quality of the input wind fields.

scholarly journals Nettuno: Analysis of a Wind and Wave Forecast System for the Mediterranean Sea

2013 ◽  
Vol 141 (9) ◽  
pp. 3130-3141 ◽  
Author(s):  
Luciana Bertotti ◽  
Luigi Cavaleri ◽  
Layla Loffredo ◽  
Lucio Torrisi
Keyword(s):  
High Resolution ◽  
Detailed Analysis ◽  
Mediterranean Sea ◽  
Altimeter Data ◽  
Forecast System ◽  
Extensive System ◽  
Wave Forecast ◽  
Wave Heights ◽  
The Mediterranean ◽  
Positive Results

Abstract Nettuno is a wind and wave forecast system for the Mediterranean Sea. It has been operational since 2009 producing twice-daily high-resolution forecasts for the next 72 h. The authors have carried out a detailed analysis of the results, both in space and time, using scatterometer and altimeter data from four different satellites. The findings suggest that there are appreciable differences in the measurements from the different instruments. Within the overall positive results, there is also evidence of differences in Nettuno performance for the various subbasins. The related geographical distributions in Nettuno performance are consistent with the various satellite instruments used in the comparisons. The extensive system of buoys around Italy is used to highlight the difficulties involved in a correct modeling of wave heights in Italy's coastal areas.

scholarly journals From 1/4° to 1/8°: Influence of Spatial Resolution on Eddy Detection Using Altimeter Data

2021 ◽  
Vol 14 (1) ◽  
pp. 149
Author(s):  
Yinuo Wang ◽  
Xiaoyan Chen ◽  
Guiyan Han ◽  
Pingping Jin ◽  
Jie Yang
Keyword(s):  
Mediterranean Sea ◽  
Spatial Resolution ◽  
Propagation Distance ◽  
Altimeter Data ◽  
The South ◽  
North West ◽  
Temporal Sampling ◽  
The North ◽  
The Mediterranean ◽  
Eddy Detection

A substantial portion of ocean eddies, especially small ones, may be missed due to insufficient spatial or temporal sampling by satellite altimetry. In order to illustrate the influence of spatial resolution on eddy detection, this study provides a comparison of eddy identification, tracking, and analysis between two sets of merged altimeter data with spatial resolutions of 1/4° and 1/8°. One main study area (the Mediterranean Sea), and three confirmatory areas (the South-China Sea, the North-West Pacific, and the South-East Pacific) are chosen. The results show that the number and density of eddies captured by the 1/8° data are about twice as much as those captured by the 1/4° data, while the ratios of corresponding eddy parameters, i.e., radius, amplitude, (eddy kinetic energy (EKE)) are about 0.6–0.8 (1.3) for the two datasets (1/8° ÷ 1/4°). Long-term eddy tracking (1993–2018) is conducted in the Mediterranean Sea, indicating that the improvement in spatial resolution will increase the observed values of both the lifetime and the propagation distance of robust eddies. The number of eddies identified using the 1/4° data only accounts for ~30% to 60% of those identified using the 1/8° data. However, for eddies that can be detected using the two datasets, ~5% to 10% present errors (i.e., confusion). In comparison between the four regions, we find that for the enclosed seas with complex conditions, the increase in spatial resolution may lead to more significant improvements in the efficiency and accuracy of eddy detection.

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