How it's made: Metocean Models: What's Available in the Market

In the How It’s Made series, we’re going under the hood of weather forecasting and exploring the Five Categories that help make your weather forecast. Each article in the series is a stand-alone story, but together they explain precisely how the Five Categories tie together to take a weather forecast from good to great.

Today we’re focusing on the Category Two: Metocean models, and, specifically, exploring what models are available in the market.
 

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The weather today tells you a lot about the weather tomorrow. Using meteorological and oceanographic (metocean) models, experts can analyze current weather conditions and historical data to predict future conditions.

 

These numerical models are sophisticated computer programs, in which the laws of physics, chemistry, fluid motion, and a coordinate system are all considered. A modeler maps the relevant properties of the earth onto a 2D or 3D grid, on which the model is then run. Winds, heat transfer, solar radiation, relative humidity, and surface hydrology are all calculated per grid cell, and the interactions with neighboring cells are used to predict future metocean properties. 

 

Metocean models are also an input for the statistical methodologies used for statistical on-top processing: Category Three in the weather forecasting methodology.

Experts use models from both external data sources and also develop their own in-house models. Today we’re exploring the external models available in the market.  
 

The data we receive from our global and regional weather suppliers is included in all of the work we do and embedded in all of the in-house models we run. The data is key to our business and we are thankful all of the innovation in the market. Different external models have different strengths depending on region, forecast time-step and type of weather. Our experts and modelers use these insights to get the most value out of the data and input we collect.”
- Valentijn van Gastel – Product Manager Offshore & Nautical Data


What are the main external datasets available in the market
 

External metocean models offer a range of different datasets. Weather Companies will buy specific datasets, depending on their requirements. The most commonly used global atmospheric operational datasets are as follows:

 

#1 ECMWF

ECMWF is both a research institute and also a 24/7 service that produces numerical weather models. The most important ECMWF models for weather experts are:

  • Atmospheric Model high resolution 10-day forecast (HRES)
  • Ocean Wave Model high resolution 10-day Forecast (HRES-WAM & HRES-SAW)
  • Atmospheric model Ensemble 15-day forecast (ENS)
  • Ocean Wave Model Ensemble 15-day forecast (ENS-WAM)

 

What is the coverage? For all datasets the coverage is global.

How does it work? The temporal resolution of the models ranges from 3 to 6 hours, depending on the specific dataset. For high res models, the output covers up to 10 days, while the output from other datasets can cover up to 32 days for the extended long-term forecast. The spatial resolution ranges from 0.125° to 0.5°, depending on the dataset. There are four issues from the models each day, using 0, 06, 12 and 18 UTC data.

Who runs the model? European Centre for Medium-Range Weather Forecasts

 

#2 UKMO

The UK Met Office supplies historical data, forecast data, and specialist datasets, providing both atmospheric and oceanographic datasets.

 

What is the coverage? Coverage of the models range from global through to European or UK specific

How does it work? The temporal resolution ranges  1 to 6 hours. The maximum lead time for the models vary, with the UKV and Wave UK and North Sea models covering 36 hours, and the Global model covering 144 hours. The number of issues from the models ranges between 2 and 8 per day.

Who runs the model? UK Met Office

 

#3 NCEP

NCEP delivers US and global weather guidance, forecasts, and analysis to its partners and external users. The most important NCEP models for weather experts are:

  • NCEP GFS
  • NCEP Ensemble
  • NOAA WW3
  •  

What is the coverage? Coverage of the models is global

How does it work? The temporal resolution of the models ranges from 1 to 12 hours, depending on the specific dataset. The spatial resolution ranges from 0.1° to 1.0°, depending on the dataset. Output for the models ranges from 48 hours to 385 hours. There are four issues from the models each day, apart from the Real-Time Ocean Forecast System (RTOFS) which has one issue.

Who runs the model? National Centers for Environmental Prediction

 

In addition to using models from ECMWF, UKMO, and NCEP, Weather Companies can decide to purchase datasets from national meteorological offices, such as KNMI and DWD (Deutsche Wetterdienst). And to complement external datasets, the most sophisticated Weather Companies also create metocean models that are developed by their in-house scientists.

 

How a multi-model approach increases forecast accuracy
 

There’s no such thing as an ultimate weather model, which always provides the best weather predictions. Each model has its own characteristics, and will perform better in some certain weather conditions or regions but worse in others. Therefore, Metocean experts use a combination of models to optimize for accuracy.

 

How metocean experts add value to the model data

 

External metocean models data is a key component of your weather forecast. For example, in agriculture, data from the models contributes to long-term forecasts for trading and helps provide early warnings for weather conditions that could affect crop growth.

Likewise, for companies working in shipping, offshore, energy, and transport, external metocean models support near real-time monitoring of the weather. This insight is essential for companies to make confident weather-based decisions, keep projects on schedule, and ensure the safety of personnel and equipment is maintained.

But the data from the models alone is not enough. Working with a specialist Weather Company, means you can get advise on how the model data should be used and, importantly, how it can help you avoid bad decisions made using misinterpreted model output data. A metocean modeling company will offer several key benefits, including:

● (statistical) multi-models approaches, enhancing data from external providers;

● ensemble forecasts that aggregate 50 scenarios for probabilistic forecasting and to estimate risk and confidence to the forecasts; and

● two- or three-year archives of model forecasts.

But the real value comes in helping companies understand the likely future weather conditions and how these conditions will impact on operations and projects. Access to accurate and complete data, with customizable coverage, is essential to mitigate risk. By providing the best quality datasets, assessed against both station observation networks and end-customer observation data, metocean experts support their customers to get more value from the data.

 

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The data we receive from our global and regional weather suppliers is included in all of the work we do and embedded in all of the in-house models we run. The data is key to our business and we are thankful all of the innovation in the market. Different external models have different strengths depending on region, forecast time-step and type of weather. Our experts and modelers use these insights to get the most value out of the data and input we collect.



Valentijn van Gastel

Product Manager Offshore & Nautical Data
MeteoGroup