Aviation is probably the safest mode of mass transportation available. It is also among the most complex, with many elements contributing to the relatively low rate of accidents and deaths. Among those elements is weather forecasting.
As well as the obvious safety aspect, there are environmental considerations. Bad weather forced airlines to fly one million extra kilometers in 2019, burning more than 6,000 tons of extra fuel that produced 19,000 tons of CO2, according to a 2021 study carried out by Egis and the UK Met Office on behalf of Eurocontrol (the European organization for the safety of air navigation).
At the regulatory level there is a slew of international standards, recommended practices, procedures and guidance for aeronautical meteorological service providers to fall in line with. “This ensures a uniform provision of service whenever and wherever an aviation operation is taking place in the air or on the ground,” explains Greg Brock, head of services for aviation at the WMO.
The WMO and the International Civil Aviation Organization (ICAO) have an extensive list of rules and regulations for aviation. They both work closely with other partners including the International Air Transport Association (IATA), the International Federation of Air Line Pilots’ Associations (IFALPA) and the International Federation of Air Traffic Controllers’ Associations (IFATCA).
Aviation hazards can be anything from crosswinds and ice storms to hurricanes and ash clouds from volcanic eruptions. The formal list covers wind, temperature, visibility (including obscuration thereof, such as fog), pressure, precipitation (rain, snow), sand and dust storms, thunderstorms, hail, cloud type, cloud base/top, convection, icing, turbulence, volcanic ash, space weather, releases of radioactive material, tropical cyclones and more. Each poses its own level of danger and needs to be forecast and monitored.
The WMO’s most recently updated aviation hazards guidance covers everything from wake vortices to lightning. “Of course, to deliver the services that aviation users demand ‘on time and in full’ – and for which aviation users often pay through landing charges, en-route charges and suchlike – there are the necessary underpinnings of scientific R&D and infrastructure,” says Brock.
Much of that is happening in the wider scientific community due to more investigation on climate change and the increase in extreme weather events, both of which directly impact aviation. The Eurocontrol report cites two areas of particular threat to aviation in the years ahead:
- Extreme sudden rainfall and rising sea levels with two-thirds of coastal or low-lying airports in Europe expected to be at greater risk of flooding in the event of a storm surge;
- Major storms, which cost aviation an estimated €2.2bn (US$2.4bn) in 2019 in terms of en-route delays, are likely to increase in intensity.
While 91% of coastal airports in Europe are smaller and less network-critical, major airports are intensifying their contingency planning to include climate-change risk assessments. According to Eurocontrol, a one-day airport closure triggered by flash floods could cost from €3m (US$3.3m) for a medium-size airport up to €18m (US$19.8m) for a major hub, in terms of diverted and canceled flights and clean-up measures.
One of the world’s biggest hubs, London Heathrow Airport, works closely with the UK Met Office on bad weather mitigation. The government department provides regulated weather services for all civil aerodromes in the UK and additional enhanced services for several major airports.
Meteorological staff can be based at an airport or remotely at the Met Office’s headquarters in Exeter to provide support to enable the airports to operate safely and efficiently. “The type of weather information needed to aid decision making at an airport centers around summer and winter activities,” explains Lauren Donohue, Met Office aviation business manager. “Specifically, very cold or windy conditions and summer convective storms.”
Hubs such as Heathrow naturally want alerts about disruptive weather as early as possible. “As soon as action plans can be implemented, the disruption can be better managed through additional staff being deployed, planning to tie down equipment, or gritting/de-icing the airfield,” she says.
Thereafter, updates to the forecast that provide additional clarity on time of impact, thresholds for decision making and risk management are all key to understanding if, and how, operations may change.
Flight planning is more tactical
The story is a little different for flight planning and en-route services. Donohue comments, “The information tends to be more tactical in nature, where the wind forecast is used as the initial basis for the route the flight may take. However, once in the air the pilot can request weather uplinks, for example via the Met Office’s 4-Dimensional Trajectory service, which helps identify optimizations in flight as well as avoid thunderstorms and turbulence.”
A new World Area Forecast System (WAFS) upgrade is coming from the Met Office in November 2023. It will provide a major enhancement to the detail available for atmospheric data and will be particularly useful for flight planning. As a general rule, Donohue stresses the importance of clear messaging around the weather type. “Many users do not have a deep understanding of how weather phenomena may evolve, so clear thresholds in wind strength or precipitation can help them estimate risk,” she explains.
“Meteorologists are not aeronautical experts either and will not advise on the likely impacts or cause of action for an airport or airline, but rather demonstrate what the meteorological conditions may bring.”
Airports use observation capabilities such as temperature, pressure, rainfall and winds to understand weather parameters. These are available in the tower and to airfield operations teams to make them aware of the ‘here and now’ conditions. “In addition, many airfields have sensors in the runway to determine the temperature of the runway and how it may be affected by very hot or cold conditions,” says Donohue.
While several apps and online sources can provide free weather information, expert weather services are tailored to airports. They take into account the local area and specific detail of the airport’s location and type of operations. The Met Office’s OpenRunway and Network Weather Resilience (NWR) services are examples of solutions that are available both in an operations room as well as out on the airfield.
One aim at the Met Office is to increase the resolution of its forecasts, as well as the number of ensembles, to provide more certainty and detail in the forecast. “We are going to be refreshing our Aviation Visualization Services over the next few years and understanding the desires for additional weather information will be key,” reveals Donohue.
Typhoons and lightning
Another major global gateway in Asia-Pacific, Hong Kong International Airport (HKIA), works closely with the Hong Kong Observatory (HKO), the designated meteorological authority providing weather services for aviation, much as in the UK.
The HKO operates the Airport Meteorological Office (AMO) in the airport to monitor hazardous weather phenomena that might affect the safety of airport operations and aircraft in flight. The around-the-clock Integrated Airport Centre (IAC) communicates closely with HKO’s aeronautical meteorological advisers stationed at the IAC and aviation forecasters at the AMO.
For example, during typhoon season, when a storm is approaching the city the HKO will alert the general public as well as the airport community with updates. Airport Authority Hong Kong (AAHK) will hold meetings with stakeholders – including airlines, ground services providers, cargo terminal operators, ramp operators and the Civil Aviation Department – to ensure that the airport is well prepared.
To ensure safe airport operations under lightning weather, the Airport Lightning Warning System (ALWS) was established. When the HKO detects lightning or forecasts a strike within 1km of the apron area, a red lightning warning is issued, during which ground services staff should stop working and seek shelter. At that point, all baggage, cargo and meals loading and unloading, and aircraft refueling, is suspended.
Lightning warnings are disseminated from the Apron Control Centre through an Auto Voice Message Distribution System to all frontline workers. Ramp personnel are also alerted in real time by audio and visual signals at their work sites.
Many of these, and other services, are offered by private operators as well as by state-funded weather organizations. Some of the larger players, including Finland’s Vaisala, DTN in Minneapolis and Alabama-based Baron Weather, have comprehensive products for aviation, moving forward from regulated Automated Weather Observing Systems (AWOS).
The rising cost of tropical cyclones
Vaisala serves more than 2,000 airports in approximately 170 countries. One of its new products is in the lightning segment. “We have our own global lightning detection system providing lightning data anywhere in the world at high resolution,” says Aleksis Kajava, the company’s director for Europe and Latin America.
The Thunderstorm Manager v1.5, released in April and part of the Xweather family of products, has introduced new weather layers for improved situational awareness and a secure alerting API (application programming interface) for integrating lightning alerts into local displays, control centers and other systems.
The new tropical cyclone layer offers intuitive visualizations that show the severity and projected path of cyclones, hurricanes and typhoons with three levels of alerts (information, warning and alarm). Losses from tropical cyclones and severe storms in the USA in 2022 cost almost US$140bn according to NOAA National Centers for Environmental Information (NCEI). Hurricane Ian alone caused losses of around US$100bn.
Vaisala invests about €60m (US$66m) in R&D, roughly 12-14% of the company’s turnover. In general, private companies tend to invest in equipment while national entities tend to focus their R&D on forecasting. The UK’s Met Office is an exception to this in that it also develops its own radars, for example.
In the USA, Baron Weather offers several data sets to mitigate a variety of conditions. The Baron Weather API enables developers of flight tracking and planning services to integrate high-quality aviation weather data. Powered by AWS (the Amazon Web Services platform for cloud computing that lets a remote computer access resources without having to install any software) and featuring a RESTful architecture, the API is a customizable data feed that Baron says “scales to the size of any organization”.
In total the company offers more than 200 meteorological data products, including more than 60 Baron exclusives, designed to protect pilots, passengers and cargo. One example is satellite-derived radar, which is useful in providing imagery for areas not covered by traditional land-based radar. “This data set is particularly helpful in identifying storms developing offshore, such as cyclones and hurricanes,” says a Baron spokesperson.
A key concern during thunderstorm seasons is the risk of strong downburst or microburst winds that have the potential to blow at 130-160km/h or more, in and around airports. “These winds are typically small in area, but exceptionally hard to predict and can occur suddenly and with ferocity,” says Brad Nelson, solution engineer and meteorologist at DTN.
He adds, “The threats are not only to the airport but to air traffic itself as these winds have brought down approaching aircraft in the past due to ‘fly up/fly down’ microbursts and have led to many near disasters.”
A dedicated meteorologist on hand
One of DTN’s solutions is Risk Communicator (RC), a holistic service for airports to help anticipate such weather impacts by partnering and working closely with a professional meteorologist. This way airport operations officials are able to get high-value, accurate information on the potential for downburst or microburst winds, for example.
The RC meteorologists monitor radar trends and communicate which thunderstorms and areas have the greatest risk of these high winds. This enables higher confidence decisions to be made with more lead time. “Airports can also staff ahead of time for these types of events and activate the Emergency Operations Center (EOC) if deemed necessary from the information provided by the RC,” says Dave Berry, aviation solutions engineer at DTN.
This kind of information as a whole is designed to feed into the collaborative decision making (CDM) process whereby all stakeholders – airports, airlines and air navigation service providers (ANSP) – can actively, but collectively, manage this kind of crucial weather event. Others might include straight-line winds and tornadoes.
By using RC to feed in alerts of a tornado risk, ideally 30 minutes or more ahead of time, this also offers greater confidence when high winds and tornadoes might come close but are expected to miss the airport. In that scenario, a decision to keep the airport open and functioning normally can lead to big cost savings.
From these few examples, it is clear that severe weather mitigation options for the aviation industry are varied. From dedicated systems to APIs and remote cloud platforms, the choices are numerous and growing. But perhaps the overriding factor should be ease of use and clarity of message.
“For aviation stakeholders, it’s vital to get weather information in the right kind of format so that it’s easy to interpret and take action,” says Vaisala’s Kajava. “Moving from the legacy of cryptic, short messages such as METAR to more comprehensive weather information is going to be the trend.”
This article originally appeared in the September 2023 issue ofMeteorological Technology International. To view the magazine in full click here.