Data and weather graphics systems
Nov 1, 2009 12:00 PM, Ran Yakir
Unique challenges face global weather presentation.
Differences in weather reporting culture and the climatic nature of each region often dictate the use of various types of weather data.
Displaying high-quality television weather forecasts can sometimes present huge challenges to broadcasters. For a start, there is no standard format to follow. Regional differences, both cultural and technical, make it difficult to bolt weather on to many standard graphics systems broadcasters may have already installed.
Before weather graphics systems can generate an easily-understood, informative weather display, they must first access or ingest timely weather data, such as current temperature, humidity, rainfall and wind, as well as future forecasts. Then a designer has to consider how frequently the systems will receive the data and how often they will need to display a new, updated weather show. For a rolling, 24-hour news channel, frequent data updates and real-time rendering would be essential to generate the latest weather graphics.
When investing in weather graphics technology, broadcasters have to consider two main aspects: How well will the graphics system display a memorable weather show that complements the branded look and feel of the channel, and what kind of weather data will be used to drive it?
National styles
Typically, broadcasters prefer weather graphics systems that use weather data fed by local meteorological providers who are familiar with the weather issues that regularly crop up in their own backyards: hurricanes and tornadoes in the United States, bushfires in Australia or typhoons in Asia. Moreover, different TV channels have adopted specific weather reporting cultures over the years. For example, in the United States, one can rarely watch a weather report that does not contain a radar display in it, while in France, TV stations always show weather forecasts as zones of similar weather (rain, snow, sunshine, etc.) animating over a map of the country.
Broadcasters that break with a long-established presentation style may do so at their peril. For example, this proved to be the case for the BBC in the UK, when it introduced an animated, tilted perspective of a 3D map in its weather report four years ago. This was a major departure from the network's previous 2D overhead map view, which was an electronic version of a magnetic map board with stick-on weather symbols. Right away the network was bombarded with angry calls from viewers, which eventually led to questions being asked in the House of Parliament. Some complained that the change in style was confusing. Others said the new 3D fly-over display made them feel airsick, and the Scots felt the design was insulting to Scotland, which, being at the far end of the tilted map, now appeared “smaller.”
Weather data interpretation
The differences in weather reporting culture and the climatic nature of each region often dictate the use of different types of weather data. This is not to say broadcasters in different regions use only region-specific data. A lot of the data used by weather systems, such as measurements or forecasts, comes from common sources such as the National Oceanic and Atmospheric Administration (NOAA). However, commercial weather data vendors often create their own value-added, region-specific weather data products.
Ran Yakir is head of Vizrt research and development, weather and maps.
The modern real-time weather graphics system has evolved to be consistent with other broadcast graphics so forecasts can be integrated directly into newsroom systems and workflows. Shown here are Vizrt weather graphcs in use at The Weather Channel.
Accurate measurements are at the core of weather forecasting: Measurements could be taken by weather stations, measuring temperature, wind speed and direction, barometric pressure, etc.; but they are also taken by weather radar and weather satellites. Combining these snapshot measurements tells us the weather conditions in the past and the present. This information is fed into complex numerical models that forecast what the weather is likely to be in the future.
The most common way of forecasting weather is by using a grid. Weather conditions are forecast for the areas represented by each rectangular cell in the grid. The finer the grid, the smaller the rectangular cells, and this smaller sampling area gives a more accurate weather forecast for every point within the grid cells. However, the finer the grid, the more cells it contains, and therefore, the greater the computing power required to analyze and process the raw data.
A popular gridded weather forecast product is the Global Forecast System (GFS), produced by NOAA and distributed freely over the Internet. Many weather data providers use this product at the core of their basic offering. GFS calculates roughly 200 weather parameters (such as pressure, temperature, humidity, precipitation, cloud cover, etc.) at a grid resolution of one degree (70mi at the equator).
Because a 70mi × 70mi area is large enough to be affected by different weather conditions, GFS is not considered to be an accurate weather predictor. Therefore, various organizations have established finer resolution computational models for specific regions or the entire world. It is common to find forecast models at quarter-degree resolution or even at 0.5mi to 1mi resolution for each grid cell, depending on the forecast area and on the computational power available.
The hundreds of weather parameters in gridded forecasts are used to show a large variety of the weather displays on TV. One of the challenges for broadcasters is to differentiate themselves by presenting this data in a way that will not only be informative and well understood, but also dynamic and branded. For example, a rainfall forecast display could show amoeba-like blue blobs moving slowly over a 2D map, but it could also be visualized using animated raindrops falling on the relevant areas on a map branded with the station ID.
The importance of climate change and its effects has put the topic of weather firmly on the agenda of mainstream news. Having a style of presenting weather news that is consistent with other news and after it, with the forecast, is now part of a channel's branding strategy. In a similar way, weather presenters find themselves taking on the role of weather news correspondents to explain breaking weather news phenomena around the world, on top of predicting whether it will be safe to hold a barbecue during the coming weekend.
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