References of "Barth, Alexander"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailEnsemble perturbation smoother for optimizing tidal boundary conditions by assimilation of High-Frequency radar surface currents - application to the German Bight
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Gurgel, Klaus-Werner et al

in Ocean Science (2010), 6(1), 161-178

High-Frequency (HF) radars measure the ocean surface currents at various spatial and temporal scales. These include tidal currents, wind-driven circulation, density-driven circulation and Stokes drift ... [more ▼]

High-Frequency (HF) radars measure the ocean surface currents at various spatial and temporal scales. These include tidal currents, wind-driven circulation, density-driven circulation and Stokes drift. Sequential assimilation methods updating the model state have been proven successful to correct the density-driven currents by assimilation of observations such as sea surface height, sea surface temperature and in-situ profiles. However, the situation is different for tides in coastal models since these are not generated within the domain, but are rather propagated inside the domain through the boundary conditions. For improving the modeled tidal variability it is therefore not sufficient to update the model state via data assimilation without updating the boundary conditions. The optimization of boundary conditions to match observations inside the domain is traditionally achieved through variational assimilation methods. In this work we present an ensemble smoother to improve the tidal boundary values so that the model represents more closely the observed currents. To create an ensemble of dynamically realistic boundary conditions, a cost function is formulated which is directly related to the probability of each boundary condition perturbation. This cost function ensures that the boundary condition perturbations are spatially smooth and that the structure of the perturbations satisfies approximately the harmonic linearized shallow water equations. Based on those perturbations an ensemble simulation is carried out using the full three-dimensional General Estuarine Ocean Model (GETM). Optimized boundary values are obtained by assimilating all observations using the covariances of the ensemble simulation. [less ▲]

Detailed reference viewed: 81 (8 ULg)
See detailEnsemble-based assimilation of high-frequency radar surface currents in regional ocean models
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Beckers, Jean-Marie ULg et al

Conference (2010)

The results of coastal ocean models depend critically on the accuracy of boundary and initial conditions and atmospheric forcing. The precision of coastal ocean models is limited among others by ... [more ▼]

The results of coastal ocean models depend critically on the accuracy of boundary and initial conditions and atmospheric forcing. The precision of coastal ocean models is limited among others by uncertainty in those forcing fields. Since high-frequency (HF) radar installations provide measurements over a relatively large area, the assimilation of these data has a high potential to reduce the errors in ocean models and to provide a dynamically consistent estimation of the ocean circulation. The assimilation of HF radar data is not without its own challenges: the spatial variation of the surface currents uncertainty, the high temporal resolution of HF radar data, the simultaneous presence of a wide range of processes with distinct spatial and temporal scales (tides and other surface gravity waves, mesoscale and wind-driven circulation), and the generally strong sensitivity of regional models to errors in the boundary conditions and atmospheric forcings. These processess are important aspects to consider in the application of data assimilation methods to HF radar measurements. The results of two data assimilation experiments on the West Florida Shelf (WFS) and the German Bight are presented. HF radar currents are assimilated in a nested West Florida Shelf based on an ensemble of model realizations with different wind forcings. The model is sequentially updated and a filter is implemented to reduce spurious surface-gravity waves. Results of the WFS model assimilating surface currents show an improvement of the model currents not only at the surface but also at depth compared to independent ADCP observations. This West Florida Shelf assimilation experiment does not include tides. Tides are not generated within the domain, but are rather propagated inside the domain through the boundary conditions. The potential of using HF radar data to reduce errors in tidal boundary conditions is shown in a model setup of the German Bight. For improving the modeled tidal variability it is not sufficient to update the model state without updating the boundary conditions. An ensemble smoother to improve the tidal boundary values is presented and validated with independent HF radar measurements and tide-gage data. The ensemble-scheme is also applied to improve the wind forcing by assimilation of surface currents. The improvement of the analyzed wind forcing is assessed by using in-situ wind measurements. [less ▲]

Detailed reference viewed: 25 (2 ULg)
See detailEnsemble smoother for optimizing tidal boundary conditions and wind forcing by assimilation of High-Frequency Radar surface currents measurements of the German Bight
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Staneva, Joanna et al

Conference (2010)

An ensemble smoother scheme is presented to assimilate HF radar surface currents to improve tidal boundary conditions and wind forcings of a circulation model of the German Bight. To create an ensemble of ... [more ▼]

An ensemble smoother scheme is presented to assimilate HF radar surface currents to improve tidal boundary conditions and wind forcings of a circulation model of the German Bight. To create an ensemble of dynamically realistic tidal boundary conditions, a cost function is formulated which is directly related to the probability of each perturbation. This cost function ensures that the perturbations are spatially smooth and that the structure of the perturbations satisfies approximately the harmonic linearized shallow water equations. Based on those perturbations an ensemble simulation is carried out using the full three-dimensional General Estuarine Ocean Model (GETM). Optimized boundary values are obtained using all observations within the assimilation period using the covariances of the ensemble simulation. The approach acts like a smoother scheme since all observations are taken into account. Since the scheme aims to derive the optimal perturbation, it might be called Ensemble Perturbation Smoother. The final analysis is obtained by rerunning the model using the optimal perturbation to the boundary conditions. The analyzed model solution satisfies thus the model equations exactly and does not suffer from spurious adjustments often observed with sequential assimilation schemes. Model results are also compared to independent tide gage data. The assimilation did also reduce the model error compared to those sea level observations. The same scheme has also been used to correct surface winds. Surface winds are crucial for accurately modeling the marine circulation in coastal waters. The method is validated directly by comparing the analyzed wind speed to in situ measurements and indirectly by assessing the impact of the corrected winds on sea surface temperature (SST) relative to satellite SST. [less ▲]

Detailed reference viewed: 15 (1 ULg)
See detailEstimation of tidal boundary conditions and surface winds by assimilation of high-frequency radar surface currents in the German Bight
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Gurgel, Klaus-Werner et al

Conference (2010)

Numerical ocean models are affected by errors of various origins: errors in the initial conditions, boundary conditions and atmospheric forcings, uncertainties in the turbulence parametrization and ... [more ▼]

Numerical ocean models are affected by errors of various origins: errors in the initial conditions, boundary conditions and atmospheric forcings, uncertainties in the turbulence parametrization and discretization errors. In data assimilation, observations are used to reduce the uncertainty in the model solution. Ensemble-based assimilation schemes are often implemented such that the expected error of the model solution is minimized. It is shown that the observations can also be used to obtain improved estimates of the, in general, poorly known boundary conditions and atmospheric forcings. An ensemble smoother scheme is presented to assimilate high-frequency (HF) radar surface currents to improve tidal boundary conditions and wind forcings of a circulation model of the German Bight. To create an ensemble of dynamically realistic tidal boundary conditions, a cost function is formulated which is directly related to the probability of each perturbation. This cost function ensures that the perturbations are spatially smooth and that the structure of the perturbations satisfies approximately the harmonic linearized shallow water equations. Based on those perturbations an ensemble simulation is carried out using the full three-dimensional General Estuarine Ocean Model (GETM). Optimized boundary values are obtained using all observations within the assimilation period using the covariances of the ensemble simulation. The approach acts like a smoother scheme since past and future observations are taken into account. The final analysis is obtained by rerunning the model using the optimal perturbation of the boundary conditions. The analyzed model solution satisfies thus the model equations exactly and does not suffer from spurious adjustments often observed with sequential assimilation schemes. Model results are also compared to independent tide gauge data. The assimilation also reduces the model error compared to those sea level observations. The same scheme is also used to correct surface winds. Surface winds are crucial for accurately modeling the marine circulation in coastal waters. The method is validated directly by comparing the analyzed wind speed to in situ measurements and indirectly by assessing the impact of the corrected winds on sea surface temperature (SST) relative to satellite SST. [less ▲]

Detailed reference viewed: 17 (5 ULg)
See detailAssimilation of high-frequency radar surface currents measurements to optimize tidal boundary conditions and wind forcing
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Gurgel, Klaus-Werner et al

Conference (2010)

An ensemble smoother scheme is presented to assimilate high-frequency (HF) radar surface currents to improve tidal boundary conditions and wind forcings of a circulation model of the German Bight. To ... [more ▼]

An ensemble smoother scheme is presented to assimilate high-frequency (HF) radar surface currents to improve tidal boundary conditions and wind forcings of a circulation model of the German Bight. To create an ensemble of dynamically realistic tidal boundary conditions, a cost function is formulated which is directly related to the probability of each perturbation. This cost function ensures that the perturbations are spatially smooth and that the structure of the perturbations satisfies approximately the harmonic linearized shallow water equations. Based on those perturbations an ensemble simulation is carried out using the full three-dimensional General Estuarine Ocean Model (GETM). Optimized boundary values are obtained using all observations within the assimilation period using the covariances of the ensemble simulation. The approach acts like a smoother scheme since past and future observations are taken into account. The final analysis is obtained by rerunning the model using the optimal perturbation of the boundary conditions. The analyzed model solution satisfies thus the model equations exactly and does not suffer from spurious adjustments often observed with sequential assimilation schemes. Model results are also compared to independent tide gage data. The assimilation also reduces the model error compared to those sea level observations. The same scheme is also used to correct surface winds. Surface winds are crucial for accurately modeling the marine circulation in coastal waters. The method is validated directly by comparing the analyzed wind speed to in situ measurements and indirectly by assessing the impact of the corrected winds on sea surface temperature (SST) relative to satellite SST. [less ▲]

Detailed reference viewed: 9 (2 ULg)
Full Text
See detailDIVA: new features
Beckers, Jean-Marie ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

Scientific conference (2009, October 23)

Detailed reference viewed: 16 (2 ULg)
See detailEnsemble smoother for optimizing tidal boundary conditions and bottom roughness by assimilation of High-Frequency Radar surface currents
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Staneva, J. et al

Conference (2009, September)

High-Frequency (HF) radars measure the ocean currents at various spatial and temporal scales. These include tidal currents, wind-driven circulation, density-driven circulation and Stokes drift. Sequential ... [more ▼]

High-Frequency (HF) radars measure the ocean currents at various spatial and temporal scales. These include tidal currents, wind-driven circulation, density-driven circulation and Stokes drift. Sequential assimilation methods updating the model state have been proven successful to correct the density-driven currents by assimilation of observations such as sea surface height, sea surface temperature and in-situ profiles. However, the situation is different for tides in coastal models since these are not generated within the domain, but are rather propagated inside the domain through the boundary conditions. For improving the modeled tidal variability it is therefore not sufficient to update the model state via data assimilation without updating the boundary conditions. The optimization of boundary conditions to match observations inside the domain is traditionally achieved through variational assimilation methods. In this work we present an ensemble smoother to improve the tidal boundary values so that the model represents more closely the observed currents. To create an ensemble of dynamically realistic boundary conditions, a cost function is formulated which is directly related to the probability of each perturbation. This cost function ensures that the perturbations are spatially smooth and that the structure of the perturbations satisfies approximately the harmonic linearized shallow water equations. Based on those perturbations an ensemble simulation is carried out using the full three-dimension General Estuarine Ocean Model (GETM). Optimized boundary values are obtained using all observations within the assimilation period using the covariances of the ensemble simulation. [less ▲]

Detailed reference viewed: 45 (10 ULg)
Full Text
Peer Reviewed
See detailSuper-Ensemble techniques: application to surface drift prediction
Vandenbulcke, Luc ULg; Beckers, Jean-Marie ULg; Lenartz, Fabian ULg et al

in Progress in Oceanography (2009), 82(3), 149-167

The prediction of surface drift of floating objects is an important task, with applications such as marine transport, pollutant dispersion, and search-and-rescue activities. But forecasting even the drift ... [more ▼]

The prediction of surface drift of floating objects is an important task, with applications such as marine transport, pollutant dispersion, and search-and-rescue activities. But forecasting even the drift of surface waters is very challenging, because it depends on complex interactions of currents driven by the wind, the wave field and the general prevailing circulation. Furthermore, although each of those can be forecasted by deterministic models, the latter all suffer from limitations, resulting in imperfect predictions. In the present study, we try and predict the drift of two buoys launched during the DART06 (Dynamics of the Adriatic sea in Real-Time 2006) and MREA07 (Maritime Rapid Environmental Assessment 2007) sea trials, using the so-called hyper-ensemble technique: different models are combined in order to minimize departure from independent observations during a training period; the obtained combination is then used in forecasting mode. We review and try out different hyper-ensemble techniques, such as the simple ensemble mean, least-squares weighted linear combinations, and techniques based on data assimilation, which dynamically update the model’s weights in the combination when new observations become available. We show that the latter methods alleviate the need of fixing the training length a priori, as older information is automatically discarded. When the forecast period is relatively short (12 h), the discussed methods lead to much smaller forecasting errors compared with individual models (at least three times smaller), with the dynamic methods leading to the best results. When many models are available, errors can be further reduced by removing colinearities between them by performing a principal component analysis. At the same time, this reduces the amount of weights to be determined. In complex environments when meso- and smaller scale eddy activity is strong, such as the Ligurian Sea, the skill of individual models may vary over time periods smaller than the forecasting period (e.g. when the latter is 36 h). In these cases, a simpler method such as a fixed linear combination or a simple ensemble mean may lead to the smallest forecast errors. In environments where surface currents have strong mean-kinetic energies (e.g. the Western Adriatic Current), dynamic methods can be particularly successful in predicting the drift of surface waters. In any case, the dynamic hyper-ensemble methods allow to estimate a characteristic time during which the model weights are more or less stable, which allows predicting how long the obtained combination will be valid in forecasting mode, and hence to choose which hyper-ensemble method one should use. [less ▲]

Detailed reference viewed: 105 (26 ULg)
See detailHF radar observations of surface currents in the German Bight: descriptive analysis, model-data comparison and non-sequential ensemble data assimilation
Port, A.; Staneva, J.; Schulz-Stellenfleth, J. et al

Conference (2009, September)

Detailed reference viewed: 39 (2 ULg)
Full Text
Peer Reviewed
See detailUS GODAE: Global Ocean Prediction with the HYbrid Coordinate Ocean Model (HYCOM)
Chassignet, E. P.; Hurlburt, H. E.; Metzger, E. J. et al

in Oceanography (2009), 22(2), 64-75

During the past five to ten years, a broad partnership of institutions under NOPP sponsorship has collaborated in developing and demonstrating the performance and application of eddy-resolving, real-time ... [more ▼]

During the past five to ten years, a broad partnership of institutions under NOPP sponsorship has collaborated in developing and demonstrating the performance and application of eddy-resolving, real-time global- and basin-scale ocean prediction systems using the HYbrid Coordinate Ocean Model (HYCOM). The partnership represents a broad spectrum of the oceanographic community, bringing together academia, federal agencies, and industry/commercial entities, and spanning modeling, data assimilation, data management and serving, observational capabilities, and application of HYCOM prediction system outputs. In addition to providing real-time, eddy-resolving global- and basin-scale ocean prediction systems for the US Navy and NOAA, this project also offered an outstanding opportunity for NOAA-Navy collaboration and cooperation, ranging from research to the operational level. This paper provides an overview of the global HYCOM ocean prediction system and highlights some of its achievements. An important outcome of this effort is the capability of the global system to provide boundary conditions to even higherresolution regional and coastal models. [less ▲]

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
See detailEvolution of Western Mediterranean Sea Surface Temperature between 1985 and 2005
Troupin, Charles ULg; Lenartz, Fabian; Sirjacobs, Damien ULg et al

Conference (2009, April 20)

Detailed reference viewed: 13 (2 ULg)
Full Text
Peer Reviewed
See detailThe Surface Circulation of the Caribbean Sea and the Gulf of Mexico as Inferred from Satellite Altimetry
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Weisberg, Robert H.

in Journal of Physical Oceanography (2009), 39(3), 640657

The surface circulation of the Caribbean Sea and Gulf of Mexico is studied using 13 years of satellite altimetry data. Variability in the Caribbean Sea is evident over several time scales. At the annual ... [more ▼]

The surface circulation of the Caribbean Sea and Gulf of Mexico is studied using 13 years of satellite altimetry data. Variability in the Caribbean Sea is evident over several time scales. At the annual scale, sea surface height (SSH) varies mainly by a seasonal steric effect. Interannually, a longer cycle affects the SSH slope across the current and hence the intensity of the Caribbean Current. This cycle is found to be related to changes in the wind intensity, the wind stress curl, and El Niño–Southern Oscillation. At shorter time scales, eddies and meanders are observed in the Caribbean Current, and their propagation speed is explained by baroclinic instabilities under the combined effect of vertical shear and the β effect. Then the Loop Current (LC) is considered, focusing on the anticyclonic eddies shed by it and the intrusion of the LC into the Gulf of Mexico through time. Twelve of the 21 anticyclonic eddies observed to detach from the LC are shed from July to September, suggesting a seasonality in the timing of these events. Also, a relation is found between the intrusion of the LC into the Gulf of Mexico and the size of the eddies shed from it: larger intrusions trigger smaller eddies. A series of extreme LC intrusions into the Gulf of Mexico, when the LC is observed as far as 92°W, are described. The analyses herein suggest that the frequency of such events has increased in recent years, with only one event occurring in 1993 versus three from 2002 to 2006. Transport through the Straits of Florida appears to decrease during these extreme intrusions. [less ▲]

Detailed reference viewed: 147 (15 ULg)
Full Text
Peer Reviewed
See detailA nested model of the Cariaco Basin (Venezuela): description of the basin’s interior hydrography and interactions with the open ocean
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Weisberg, Robert H.

in Ocean Dynamics (2009), 59(1), 97-120

A high-resolution (1/60°), three-dimensional numerical circulation model of the Cariaco Basin (Venezuela) is constructed by nesting the Regional Ocean Modeling System (ROMS) in the 1/12° global Hybrid ... [more ▼]

A high-resolution (1/60°), three-dimensional numerical circulation model of the Cariaco Basin (Venezuela) is constructed by nesting the Regional Ocean Modeling System (ROMS) in the 1/12° global Hybrid Coordinate Ocean Model (HYCOM). A new bathymetry, computed by merging DBDB2 data and in situ depth measurements using optimal interpolation, is described. This new bathymetry corrects the depth of the channels that connect the Cariaco Basin with the open ocean and which play a very important role in the basin circulation. Results from a 2004 ROMS hindcast are presented. Observations (temperature, salinity, and currents) are used to validate the model results before using the model to describe the annual cycle of the Cariaco Basin and the interactions between the basin and the open ocean. Two modes of interaction are described, the first being the meanders and eddies that travel westward with the Caribbean Current, and the second being a subsurface eastward current that flows along the north coast of South America. The circulation path within the basin is directly related to the intensity of this current. Both mechanisms described play a role in the ventilation of the basin. The present study is also an example of the feasibility of one of the objectives of GODAE (Global Ocean Data Assimilation Experiment): downscaling from a large-scale model to a regional model. In particular, the nesting ratio of 5 used in this work demonstrates that a high-resolution model can be successfully nested in HYCOM. [less ▲]

Detailed reference viewed: 122 (16 ULg)
Full Text
Peer Reviewed
See detailImpact of GODAE products on nested HYCOM simulations of the West Florida Shelf
Halliwell, G. R.; Barth, Alexander ULg; Weiberg, R. H. et al

in Ocean Dynamics (2009), 59(1), 139-155

Nested non-assimilative simulations of the West Florida Shelf for 2004-2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean ... [more ▼]

Nested non-assimilative simulations of the West Florida Shelf for 2004-2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean products. Simulations are nested within an optimum interpolation hindcast of the Atlantic Ocean, the initial test of the US Navy Coupled Ocean Data Assimilation system for the Gulf of Mexico, and a global ocean hindcast that used the latter assimilation system. These simulations are compared to one that is nested in a non-assimilative Gulf of Mexico model to document the importance of assimilation in the outer model. Simulations are evaluated by comparing model results to moored Acoustic Doppler Current Profiler measurements and moored sea surface temperature time series. The choice of outer model has little influence on simulated velocity fluctuations over the inner and middle shelf where fluctuations are dominated by the deterministic wind-driven response. Improvement is documented in the representation of alongshore flow variability over the outer shelf, driven in part by the intrusion of the Loop Current and associated cyclones at the shelf edge near the Dry Tortugas. This improvement was realized in the simulation nested in the global ocean hindcast, the only outer model choice that contained a realistic representation of Loop Current transport associated with basin-scale wind-driven gyre circulation and the Atlantic Meridional Overturning Circulation. For temperature, the non-assimilative outer model had a cold bias in the upper ocean that was substantially corrected in the data-assimilative outer models, leading to improved temperature representation in the simulations nested in the assimilative outer models. [less ▲]

Detailed reference viewed: 23 (10 ULg)
Full Text
See detailWeekly satellite sea surface temperature around Corsica, a DINEOF analysis of AVHRR data (1998), foreseeing comparison with interpolated and modelled fields.
Sirjacobs, Damien ULg; Lenartz, Fabian ULg; Troupin, Charles ULg et al

Poster (2009, January)

Providing wide coverage and high spatio-temporal resolution, SST satellite archives are valuable sources of information for sound understanding of the ocean dynamics, including validation of ... [more ▼]

Providing wide coverage and high spatio-temporal resolution, SST satellite archives are valuable sources of information for sound understanding of the ocean dynamics, including validation of hydrodynamical modelling studies. Yet original SST fields have also many gaps (clouds, retrieval problems), but they are known to exhibit strong spatial and temporal correlations for regions of similar dynamics. This is exploited by the parameter free statistical technique DINEOF (Data Interpolation with Empirical Orthogonal Functions) [Alvera-Azcárate et al. (2005) Ocean Modell.; Beckers et al. (2006) Ocean Sciences] to produce full weekly analysis of the variability of the sea surface temperature (SST) around Corsica and in the Ligurian Sea at weekly temporal resolution during the year 1998. A detection of outliers implemented in DINEOF analysis is tested for pointing out unusual or invalid SST data. This study is realised foreseeing a comparison of DINEOF weekly averaged reconstructed fields with those obtained by interpolating methods on the same dataset (Data Interpolating Variationnal Analysis and Optimal Interpolation schemes), and with outputs of an implementation of the GHER 3D model in this area. [less ▲]

Detailed reference viewed: 66 (22 ULg)
See detailModelling error of a hydrodynamic model of the Mediterranean Sea
Vandenbulcke, Luc ULg; Rixen, M.; Beckers, Jean-Marie ULg et al

Conference (2009)

Detailed reference viewed: 15 (2 ULg)
See detailA web interface for griding arbitrarily distributed in situ data based on Data-Interpolating Variational Analysis (Diva)
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Troupin, Charles ULg et al

Conference (2009)

Spatial interpolation of observations on a regular grid is a common task in many ceanographic disciplines (and geosciences in general). It is often used to create climatological maps for physical ... [more ▼]

Spatial interpolation of observations on a regular grid is a common task in many ceanographic disciplines (and geosciences in general). It is often used to create climatological maps for physical, biological or chemical parameters representing e.g. monthly or seasonally averaged fields. Since instantaneous observations can not be directly related to a field representing an average, simple spatial interpolation of observations is in general not acceptable. Diva (Data-Interpolating Variational Analysis) is an analysis tool which takes the error in the observations and the typical spatial scale of the underlying field into account. Barriers due to the coastline and the topography in general and also currents estimates (if available) are used to propagate the information of a given observation spatially. Diva is a command-line driven application written in Fortran and Shell Scripts. The observations and parameters are specified by the user using text files. The analyzed field and the expected error variance are returned as NetCDF files. This form of interaction with Diva is very similar to other high-performance codes and is a familiar approach for ocean modelers. However it represents a steep learning curve for oceanographers from other disciplines not familiar with command-line applications and programming. To make Diva easier to use, a web interface has been developed (http://gher-diva.phys.ulg.ac.be). Installation and compilation of Diva is therefore not required. The user can directly upload his/her data in ASCII format and enter several parameters for the analysis. The analyzed field, location of the observations, and the error mask are presented as different layers using the Web Map Service protocol. They are visualized in the browser using the Javascript library OpenLayers allowing the user to interact with layers (for example zooming and panning). Finally, the results can be downloaded as a NetCDF file, Matlab file (also readable in Octave, an open source program similar to Matlab) and Keyhole Markup Language (KML) file for visualisation in applications such as Google Earth. [less ▲]

Detailed reference viewed: 58 (7 ULg)