Meteorological Applications from the Perspective of a Private Weather Provider †

: As the demand for accurate weather forecasts continues to rise, there is an increasing need for specialized meteorological services. As a result, several private weather providers have emerged, offering customized meteorological solutions to meet the diverse needs of their clients. The present study introduces several meteorology-related applications from the point of view of WeatherNews Inc. (WNI), which is a private weather company. These applications are developed to primarily assist shipping-and energy-related companies, with greater emphasis being given to vessel weather routing.


Introduction
As the market demand for high-level weather predictions and data analysis continuously increases, the need for customized meteorology-related products has become of paramount importance.As such, more and more weather providers have been established worldwide, adjusting their meteorological services to suit various clients' needs.
In this paper, several weather applications are examined from the perspective of WeatherNews Inc. (WNI), which is a private weather provider, focusing on cutting-edge solutions which reduce environmental impact.With more than thirty years in the global market, WNI is servicing numerous industries, providing a variety of services for land, sea, and air.However, this study only focuses on applications in the shipping and energy sectors, in which major developments have been introduced in the last decade.
WNI is at the forefront of weather forecasting for the shipping industry with more than a million voyages, providing weather routing services and risk analysis to optimize their voyage performance and support their operation management.For all that, weather remains the predominant factor behind every decision, without neglecting how ship characteristics and cargo type define a vessel's sensitivity to heavy weather.
The energy sector is comprised of offshore energy weather services, such as highresolution forecasts (e.g., waves/swells and wind) for oil rigs and wind farms, and applications for energy market leaders, such as renewable energy (solar/wind) predictions and power/gas demand prediction.

Data WNI Model
In this study, the operational data from Grand MASTER were used.Grand MASTER is WNI's global weather and sea forecast database.Initially, a combination of satellite observations (WNISAT, MetOp-A, and MetOp-B), aircraft observations, marine buoys (about 1400 buoys), and data from variable vessels such as WNI service vessels (over 12,000 vessels every year), World Meteorological Organization (WMO) voluntary observing vessels (about 2 of 7 4000 vessels), and research vessels was retrieved.All the collected observations were assimilated and merged with data from the global GFS atmospheric model (Global Forecast System, NOAA/NCEP) [1] and wave model (WaveWatch3, NOAA) [2], updated four times per day.For the forecasts, the Weather Research and Forecasting model (WRF, NCAR) [3] was used.For the model initialization, enriched GFS data were used, providing global forecasts with 0.125 • (8 nm) and 1 h horizontal and temporal resolution, respectively.In addition, current, tide, and sea ice data are utilized for better representation of the sea conditions.In case quantitative risk evaluation is needed, probabilistic forecasting is applied before decision making.

Offshore Energy
Offshore energy applications were designed mainly for petroleum, marine construction, and wind farm construction companies.These customers are interested in reliable high-resolution wind and wave forecasts (e.g., wave/swell periods).These companies operate vessels that are extremely sensitive to swell periods between 6 and 20 s.On average, with a 12 s swell period, a floating structure tends to start moving upwards and downwards uncontrollably.This is extremely crucial for these kinds of operations.To minimize the risk for their operations, wave spectrum forecasts were provided, in which waves are sliced up into period parts with corresponding height and direction [4].In addition to the sea status, another important aspect for similar operations is the sea current forecasts.This could be an essential factor for vessels which require keeping them at exactly the same position during the operations (dynamic positioning).These could be floating drill rigs, pipe laying, crane operations, rig decommissioning, or safety vessels near a rig.It is worth mentioning that a lot of the above offshore energy operations require the use of helicopters.For them, the constant inflow of weather conditions, such as visibility, cloud height, and windspeed at the helideck, is of vital importance.

Environmental Planning
The energy-weather products from the environmental planning section are used by energy market leaders for long-term planning, better understanding and anticipating power or gas grid demands, and avoiding supply shortages.These companies are interested in highly accurate weather forecasts, which are continuously verified against observations.Then, probability models for any given location and scale on critical parameters like temperature, wind, etc., can be derived.Based on the correlation between the optimized weather data and electricity/gas demand, machine learning algorithms and self-optimizing models allow us to accurately forecast power/gas demand at an adapted scale (global, country, or regional) depending on each client's needs.For customers whose investments are in renewable energy (wind and solar), when they evaluate potential locations for new renewable energy parks, they are particularly interested in a combination of historical data and long-term climate projections.On an operational basis, a highly accurate wind or solar power forecast is necessary for them to better price their products and balance their operations.

Vessel Motions in Heavy Weather
In order to better understand the effect of heavy weather conditions on underway vessels at this point, it is worth briefly introducing some basic information on vessel stability characteristics and the most dangerous vessel motions that can lead to damages to the cargo, the vessel itself, or the crew onboard.When a vessel floats in the sea, it is under the action of two major forces, gravity (G), a downward force that is equivalent to the weight of the body, acting at the center of gravity, and an upward vertical buoyancy force (B) which is equal to the weight of the water displaced by the immersed body (water plane) which passes through the center of the displaced volume of water (center of buoyancy).G and B lie on the same vertical center line (Figure 1, left).If the vessel heels to some angle because of an external force such as wind or waves, then the water volume displaced is larger to one side (Figure 1, right); thus, the center of buoyancy shifts to the right from B to B 1 , while at the same time, G remains in its original position.The point at which the vertical line from the new buoyancy center (B 1 ) intersects the center line is called the metacenter of the vessel (M).The distance between the G and M is the metacentric height (GM) and is a key factor in vessel stability.Depending on the relative locations of G and M, the GM can be large or small, leading to a vessel with high or low stability, respectively.The term stability refers to a vessel's ability to return (roll) to the upright position when heeled.A vessel with high GM is called stiff, and it has a relatively small rolling period (rolls quickly) which could cause damage to cargo/vessel and discomfort to the crew onboard.The rolling period is the time taken by the ship to roll from one side to the other and back again to the initial position.Vessels with small GM are known as tender.Tender vessels have a much larger rolling period; however, the angle of the maximum heel from which the vessel can return to the upright position is smaller (risk of capsizing).When M is below G, GM becomes negative, and the vessel is unstable, with a high risk of capsizing.
(B) which is equal to the weight of the water displaced by the immerse plane) which passes through the center of the displaced volume of water (c ancy).G and B lie on the same vertical center line (Figure 1, left).If the vesse angle because of an external force such as wind or waves, then the water vol is larger to one side (Figure 1, right); thus, the center of buoyancy shifts to B to B1, while at the same time, G remains in its original position.The poin vertical line from the new buoyancy center (B1) intersects the center line is acenter of the vessel (M).The distance between the G and M is the meta (GM) and is a key factor in vessel stability.Depending on the relative loca M, the GM can be large or small, leading to a vessel with high or low stability The term stability refers to a vessel's ability to return (roll) to the upright heeled.A vessel with high GM is called stiff, and it has a relatively small (rolls quickly) which could cause damage to cargo/vessel and discomfo onboard.The rolling period is the time taken by the ship to roll from one si and back again to the initial position.Vessels with small GM are known as vessels have a much larger rolling period; however, the angle of the maxim which the vessel can return to the upright position is smaller (risk of capsiz is below G, GM becomes negative, and the vessel is unstable, with a high ris It is a common phenomenon for vessels to roll, resulting in a gentle mot in heavy seas and under certain conditions, it can become uncomfortable gerous for the vessel.The ship's movement, speed, and wind/wave direction that potentially reinforce rolling to life-threatening angles of 25 degrees or Parametric rolling and synchronous rolling are two types of rolling when a vessel is traveling in rough seas.The latter can happen when the ro the vessel becomes synchronous/resonant with the wave encounter period two successive waves), then the wave increases the amplitude of the roll, an not able to return to an upright position.In extreme cases, when the wa perpendicular to the vessel, synchronous rolling can result in the capsizing On the other hand, parametric rolling refers to the conditions under sel's stability alternates as it rolls.When a vessel and waves have the sam direction, the wave length is approximately similar to the length of the v wave encounter period is close to one or half of the vessel's rolling period, able water plane fluctuates.Depending on the position of the wave crest an tive to the vessel body, the displaced water is not fixed, affecting the buoya GM.This leads to a not fixed rolling period (the vessel's stability alternates Another phenomenon that can affect a vessel and its cargo is when enough to flow masses of water over the ship's deck (green water).Vessels distance between the deck and waterline is relatively small or vessels tha susceptible to green water.The violent force of the water on deck can lead age, and in heavy seas, water can infiltrate cargo holds, damaging dry carg It is a common phenomenon for vessels to roll, resulting in a gentle motion.However, in heavy seas and under certain conditions, it can become uncomfortable and even dangerous for the vessel.The ship's movement, speed, and wind/wave direction are all factors that potentially reinforce rolling to life-threatening angles of 25 degrees or more.
Parametric rolling and synchronous rolling are two types of rolling that can occur when a vessel is traveling in rough seas.The latter can happen when the rolling period of the vessel becomes synchronous/resonant with the wave encounter period (time between two successive waves), then the wave increases the amplitude of the roll, and the vessel is not able to return to an upright position.In extreme cases, when the wave direction is perpendicular to the vessel, synchronous rolling can result in the capsizing of the vessel.
On the other hand, parametric rolling refers to the conditions under which the vessel's stability alternates as it rolls.When a vessel and waves have the same or opposite direction, the wave length is approximately similar to the length of the vessel, and the wave encounter period is close to one or half of the vessel's rolling period, then the available water plane fluctuates.Depending on the position of the wave crest and trough relative to the vessel body, the displaced water is not fixed, affecting the buoyancy center and GM.This leads to a not fixed rolling period (the vessel's stability alternates as it rolls).
Another phenomenon that can affect a vessel and its cargo is when waves are big enough to flow masses of water over the ship's deck (green water).Vessels whose vertical distance between the deck and waterline is relatively small or vessels that roll are more susceptible to green water.The violent force of the water on deck can lead to vessel damage, and in heavy seas, water can infiltrate cargo holds, damaging dry cargo.
Based on vessel reports for the last 4 years (2018-2022) regarding vessel damage cases due to the above ship motions, more than half (53%) of them were associated with low-pressure systems or fronts.Additionally, 12% of the damage cases were caused by tropical storms, 17% were due to seasonal monsoons, and 18% were due to mixed or other weather conditions.

Vessel Weather Routing-Heavy Weather Avoidance
Vessel weather routing is a service for marine customers to optimize ship navigation with the most efficient and safe voyage routes for a given voyage.This is achieved by analyzing weather/wave forecasts, patterns, and conditions considering vessel characteristics (stability, etc.) and cargo type.Optimum ship routing not only helps vessels avoid stormy weather but also helps vessels arrive on time at the destination as required by clients and promotes the optimum and least fuel consumption.In fact, this service contributed to the reduction of 2.8 million mt of CO 2 in twelve months (between June 2018 and May 2019).
Before a vessel departs from the port, the initial voyage plan (IVP) procedure starts.The vessel receives the IVP instructions, including a list of the suggested waypoints for the vessel and a detailed description of the weather for the next several days.For relatively short voyages, the weather forecast is a key factor for any decision making; however, as the voyage becomes longer (e.g., transatlantic/transpacific), the seasonal climatological conditions of the area are seriously considered.The IVP is sent to the vessel sufficient time before the estimated time of departure.Once a vessel has departed, the monitoring and the underway service procedure begins.The vessels normally receive new, updated voyage instructions every three days unless the vessel is in heavy weather or there is a special request from the Master (Captain) or the vessel operator for closer monitoring and guidance.

Initial Voyage Planning
In Figure 2a, there is an example of a westbound vessel sailing from New Orleans (USA) to Qinhuangdao (China) during the winter of 2022.In this case, the Master's sailing intentions were to cross the Pacific Ocean in a great circle, which is the shortest possible route option from point A to point B on a sphere.Even though, in theory, that route seemed the shortest and the most economical, in practice, it would not be the case due to the seasonal weather conditions.The key feature of the wintertime weather pattern in the North Pacific is the Arctic high pressure which slowly builds over the Bering Strait and pushes the main low track southward into the mid-latitudes.Given the fact that the main cyclogenesis area in the Pacific is located east of Japan, the main low track has a northeast direction, with lows generally tracking into the Aleutians Islands or, most likely, to Alaska Bay, producing an extensive area of dangerous conditions north of 40 • N. Because of all the above, a more conservative route along 31 • N was suggested by WNI and accepted by the vessel's Master.Based on post-processed model data verified against real observations, as was explained in the WNI Model section, the conditions the vessel encountered following the southern route against the conditions it would have encountered if the vessel followed the Master's initial intentions (Figure 2b) were compared.The WNI's route aimed at positioning the vessel further south of the main low track, minimizing its exposure to successive low-pressure systems associated with strong gale force winds (BF 8-9) and up to dangerous 12 m seas/swells combined.On the contrary, the vessel actually sailed under moderate to strong breezes with 2-4 m seas/swells resulting in earlier arrival by 23 h and less fuel consumption by 49 mt compared to the Master's initial intentions.

Underway Vessel Monitoring
In Figure 3a, there is an example of a westbound vessel sailing from China to the Mediterranean Sea during the summer of 2022.Approaching Sri Lanka, the weather forecast indicated that the vessel would be significantly affected by the summer monsoon in the Arabian Sea.During the summer months in the Northern Hemisphere, there is an increase in the temperature differences over the landmass of the Indian Plateau against the Arabian Sea and the Bay of Bengal due to the different heat capacities.Since surface interaction of the air mass over the land is prevented by the Himalayan mountain range, a temperature gradient forms across the region, and onshore southwesterly winds begin to blow across the North Indian Ocean.The roughest conditions, including near gale winds and 6m waves, are found north of 10 • N, between 56 • E and 63 • E. As the waves propagate from the coast of Somalia to the coast of India and Pakistan, the waves transition from wind waves to swell around 60 • E, causing the wave periods to increase as they travel northeastward.Because the vessel had sensitive cargo (heavy machinery on deck) and there was a high risk of rolling, a south diversion along 8 • N was suggested to minimize exposure to heavier conditions.After close and constant communication with the Master, the vessel sailed further southwest of Socotra Island while avoiding prolonged periods of near gale to gale force winds (BF 7-8) and over 6m seas/swells for more than 72 consecutive hours (Figure 3b).Even though the final route added 276 nm to the total sailing distance, only about 7 mts of fuel and 4.5 h of sailing distance were added as a cost to enable the vessel to safely sail through the Arabian Sea during heavy weather.

Underway Vessel Monitoring
In Figure 3a, there is an example of a westbound vessel sailing from China to t Mediterranean Sea during the summer of 2022.Approaching Sri Lanka, the weather fo cast indicated that the vessel would be significantly affected by the summer monsoon the Arabian Sea.During the summer months in the Northern Hemisphere, there is an crease in the temperature differences over the landmass of the Indian Plateau against t

Conclusions
In this study, several meteorological applications are presented from the perspective of WeatherNews Inc. (WNI), a private weather provider.According to the results, the following conclusions can be made: 1.For every weather-related application, some kind of forecast or data is initially required as an input; however, the final meteorological service is adjusted accordingly to meet the individual client needs; 2. Each vessel's characteristics and cargo type define how sensitive it is to heavy weather conditions; 3.An accurate weather forecast of the next few days is a fundamental element for an optimal voyage plan; however, for long voyages, the seasonal climatological conditions of the area should be considered as well.
Finally, future work could focus on a statistical evaluation between different routes to have a better understanding of the voyage weather routing's importance and impact.

Conclusions
In this study, several meteorological applications are presented from the perspective of WeatherNews Inc. (WNI), a private weather provider.According to the results, the following conclusions can be made: 1.
For every weather-related application, some kind of forecast or data is initially required as an input; however, the final meteorological service is adjusted accordingly to meet the individual client needs; 2.
Each vessel's characteristics and cargo type define how sensitive it is to heavy weather conditions; 3.
An accurate weather forecast of the next few days is a fundamental element for an optimal voyage plan; however, for long voyages, the seasonal climatological conditions of the area should be considered as well.
Finally, future work could focus on a statistical evaluation between different routes to have a better understanding of the voyage weather routing's importance and impact.

Figure 1 .
Figure 1.Ship stability diagram showing center of gravity (G), center of buoyancy (M), and metacentric height (GM) with ship upright (left) and heeled over to the ri

Figure 1 .
Figure 1.Ship stability diagram showing center of gravity (G), center of buoyancy (B), metacenter (M), and metacentric height (GM) with ship upright (left) and heeled over to the right (right).

Figure 2 .
Figure 2. (a) Vessel final route across Pacific Ocean versus Master's intentions (b) On the left (fi route) the encountered conditions (windspeed in knots and significant wave height in meters) vessel follow the southern final route in a period of 192 h (8 days).On the right (Master's intention the conditions vessel would have encountered if it continued following the Master's intentions.

Figure 2 .
Figure 2. (a) Vessel final route across Pacific Ocean versus Master's intentions (b) On the left (final route) the encountered conditions (windspeed in knots and significant wave height in meters) as vessel follow the southern final route in a period of 192 h (8 days).On the right (Master's intentions), the conditions vessel would have encountered if it continued following the Master's intentions.

Figure 3 .
Figure 3. (a) Vessel's final route across Arabian Sea versus the initial suggestion (b) On the left (fina route) the encountered conditions (windspeed in knots and significant wave height in meters) as vessel follows the southern diversion in a period of 192 h (8 days).On the right (initial route), the conditions vessel would have encountered if it continued following the initial route.

Figure 3 .
Figure 3. (a) Vessel's final route across Arabian Sea versus the initial suggestion (b) On the left (final route) the encountered conditions (windspeed in knots and significant wave height in meters) as vessel follows the southern diversion in a period of 192 h (8 days).On the right (initial route), the conditions vessel would have encountered if it continued following the initial route.