OPERATIONAL REVIEWWEATHER FORECASTING
conditions by the month. They can be used as guidelines to understand the general degree of risk. MatthewsDaniel’s master mariners can
also provide insights on which passage is more feasible based not only on the seasonality of weather (for example, cyclone and monsoon seasons) but also vessel size and design limitations. The weather team also uses statistical
models to examine the likelihood of exceeding engineering environmental criteria for wind and wave conditions for the planned voyage, passage options and departure dates. During a transit, MatthewsDaniel meteorologists can further equip the onboard captains with marine weather forecasts out to seven days. Forecast data is from dynamical models that numerically compute atmospheric and oceanographic interactions.
Accuracy How accurate is weather forecasting today? It is getting more dependable, said Cho, especially up to five days out although it does tail-off at seven days. Improved high-definition satellites, buoys and improved calibration of data through the increase in computer power have all helped. A large contribution to the improvement
in accuracy comes from modern technology, such as satellites, GPS tracking and parallel computing. The ability to process large data volumes allowed more information to be collected. Consequently, Cho stated: “We can
cross-confirm data accuracy among captured or measured data before using them to fine-tune forecast models. In the absence of abundant data in the past, there was not a good way to cross-check whether equipment collected data accurately. It is possible we had fine-tuned models to incorrect data to a certain degree.” Improvement in computing power has
also contributed to model accuracy by making it possible to couple formerly independent models for various environmental disciplines. For example, MatthewsDaniel’s weather research and development department is working on coupling astronomical and storm tide
While the trend may be towards a warming world, that does not mean we will not still get cold, stormy winters or mild summers. – The Met Office
82 January/February 2017
South Korean heavy lift shipping company TPI Megaline has just chosen ABB’s predictive Octopus marine software for one of its vessels, Mega Caravan.
Putting weather data to use
Tim Ellis, marketing manager for marine software and analytics at ABB in the Netherlands, claims that his company’s Octopus software suite is the industry leader in vessel motion prediction solutions. “The system combines wave measurements, weather forecasts, and navigation data like speed, course, RPM and the voyage plan, with ship characteristics, loading conditions, and motion sensor measurements,” he said. This allows for simulation and forecasting of a
ship’s responses and performance. “Our system gives the master of the vessel a clear indication of what the effects of any kind of weather will be on the overall vessel motions [as well as in any given point of the vessel or cargo],” said Ellis. Modern software can be combined with sensors
on board the ship which, together with the loading parameters of the cargo, can all be used to produce a ‘polar chart’ which indicates the safest heading and speed for the voyage and tells the captain what is ahead of the vessel. If necessary, areas of bad weather that could breach safe parameters can be avoided. Ships of all types use ABB’s system, said Ellis, but heavy lift vessel operators are particularly enthusiastic when it comes to reducing vessel motions. He claimed: “About 80 percent of the
semi-submersible heavy lift vessels on the market use the Octopus software. The freeboard of these ships is low and they have a relatively large open
models with wave models in order to add more accuracy in estimating peak waves. While there are agencies that claim to be able to provide forecasts beyond seven days ahead, Cho would not give them too much credence. Such forecasts will become more accurate in time but the accuracy is not there yet.
Climate change
Another question, and one that it is impossible to answer with any degree of certainty, is whether global warming is having an effect on weather patterns and the increasing frequency and severity of
deck with high value cargoes on board, so they cannot handle big waves. So it is important to plan voyages so that they are avoided.” For example, South Korean heavy lift shipping
company TPI Megaline has just chosen ABB’s predictive Octopus marine software for one of its vessels, Mega Caravan. The ship’s parameters, along with those of the load, are entered into the software and this information is combined with weather forecasts and other sensor information to calculate a motion forecast, giving the captain a clear indication of the safest and most efficient course. In addition to the motion forecast function, a three-sensor motion measurement set-up is
installed to measure motions, accelerations and velocities on the vessel. Customers can retrieve the latest information with regards to the motion behaviour of the vessel online. After the voyage, the recorded data can be evaluated and the impact on the cargo analysed. As well as shipboard software, ABB also offers an office module, which is used for seakeeping analysis in order to prepare heavy lift cargo transportations at sea. Ellis concluded: “It all means that ship
operators can proceed with more confidence; it gives a real insight into how the expected weather conditions will influence the vessels’ motion behaviour. The system works purely as an advice. The decision on how to proceed during a voyage at sea will always be the captain’s final call.”
weather events.
Archive records suggest that weather events in the past were just as severe as today’s but, on the face of it, there were fewer of them. However, this was an era when such weather data could only be captured at available ports or by passing vessels. It is possible that many events were simply missed or under-estimated in the past. Some suggest that global warming is a
cyclical event. Others believe we are at the start a major upswing in global temperatures. The fact is that we cannot resolutely confirm or deny what is
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