sábado, 20 de abril de 2013

System Improves Monitoring of Waves on Brazilian Coast

Hello reader!

It follows an article published day (04/17) in the english website of the Agência FAPESP reporting that a system improves the monitoring of waves on the Brazilian Coast.

Duda Falcão

System Improves Monitoring
of Waves on Brazilian Coast

By Luiz Paulo Juttel
April 17, 2013

Operating on a supercomputer,
the Coastal Forecasting and 
Monitoring System forecasts
the movement and height of
waves at 61 points on the coast
Agência FAPESP – Monitoring and forecasting coastal processes are activities that interest several sectors of society. Data on sea waves from computer simulations allow scientists to identify the generation and arrival of energetic events, such as cyclones, so that individuals engaged in sailing, fishing and oil exploration activities can prepare.

Brazil has recently gained a mathematical modeling tool focused on this type of analysis. The Coastal Forecasting and Monitoring System (SIMCos) was developed by researchers at the National Institute for Space Research (INPE), Universidade Federal do Rio de Janeiro (UFRJ), Universidade Federal do Espírito Santo (Ufes) and Universidad Nacional Autónoma do México (Unam) to simulate diverse characteristics of waves that reach the Brazilian coast.

The platform produces information about the significant wave height, potential height, period and direction of waves that reach 61 distinct points on the country’s coast. The simulated attributes are generated based on surface wind data (10 meters above sea level).

“We calibrated the model based on the climatology of the waves in the last 30 years, from 1979 to 2010. The surface winds were calculated based on a mathematical scheme known as data assimilation. This mixes observations and results of models with spatial and temporal resolutions of 0.3125˚ and 1 h, respectively,” explained the coordinator of the project, Valdir Innocentini, of INPE.

The SIMCos is part of FAPESP’s thematic project “SMCos: monitoring system and studies of coastal processes.” The participants in the study, which began in 2007, include geologists, oceanographers, meteorologists, physicists and mathematicians. The team created to make the simulations generated by the system available to the public in real time has launched a website, which is still in its testing stages.

The unique aspect of SIMCos is not the creation of the mathematical model in itself because that modeling tool is already widely known in oceanography. The project’s novelty is the implementation of this model in a system that forecasts and monitors the movement and height of waves at several points along the Brazilian coastline.

Another highlight is the simulation and the monitoring of the potential height of waves at the 61 selected points. This calculation shows the flow of energy, the product of the square of the height and the time between the passage of two consecutive wave crests.

The INPE researchers explained that if waves that are low on the high seas have a significant height potential, they often change into high waves when they reach areas near the coast, causing movements of sediments and producing erosion. This process creates a dangerous situation for beach-goers and sailors.

The Brazilian system offers a simulation of the energy contained in the waves that will hit a particular coast in the next five days, in intervals of three hours. SIMCos also offers graphs that show the probability of waves between 0.5 and 6 meters in height at each of the 61 points analyzed.

The regions that are part of the system were selected to cover the entire Brazilian coastline. According to Innocentini, running the model daily for the country’s entire coastline would be infeasible because of the high computer processing demands.

On the high seas, those with depths of 100 meters or more, mathematical models can predict the movement of waves continuously around the globe. “In shallow waters, the velocity of waves diminishes, and the physics involved in the process becomes more complex, which makes it difficult to create efficient simulation processes and requires the use of high-performance computers to run these models,” explained Innocentini.

SIMCos is currently run on the Robura supercomputer, which cost R$ 200,000 and has more than 120 processors at INPE in São José dos Campos.

Next Steps

The data on surface winds that supply SIMCos were extracted from atmospheric models because no equipment for conducting the required surface wind measurements is located along the Brazilian coast.

According to Innocentini, the use of the atmospheric models in no way invalidates the information generated by the system for two reasons. The first reason is that these atmospheric models have a high level of precision. The second reason is that Brazilian researchers have compared SIMCos results with information on the height of waves from satellites, buoys and consolidated mathematical models that analyze coastal processes in the North Atlantic Ocean, obtaining similar data in both cases.

The next step in the study is to combine some of the data generated by SIMCos with the hydrodynamic model (MOHID) of coastal circulation developed by the Superior Technical Institute (IST) in Portugal. This model simulates the ocean currents closest to the coastline, the tides, sediment transport and erosion.

The combined use of these systems will allow for evaluation, for example, of the impact of human activity on sediment transport in coastal areas. Giant waves can drastically alter the coast in a region. Over time, however, other currents can gradually reconstruct the affected area.

“If there is some human interference, like the construction of a port or wharf, the flow of reconstructive currents could be interrupted and the sediments of that region will not be recovered. Our model can point out these cases,” explained Innocentini.

SIMCos, coupled with MOHID, could also be employed in the analysis of the impact of climatic phenomena such as El Niño and in the analysis of the effects of the alteration of the average sea level on waves and coastal regions in Brazil.


Source: English WebSite of the Agência FAPESP

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