Advancing science through flight


Asked to name the technology used in weather forecasting, a weather balloon comes to mind. Not surprisingly, the reality is more high-tech. A look at two projects using air vehicles to advance environmental science.

Helicopter observation platform

Professor Avissar (right) flying in the HOP

If the Earth’s climate is changing, is there still value in mounting scientific studies as proof? “We are only guessing at the exchanges that are happening at the Earth’s surface,” says Roni Avissar, Dean at the University of Miami’s (UM) Rosenstiel School of Marine and Atmospheric Science (RSMAS). “We need observations.”

When Avissar was asked to head up RSMAS, he was excited. First, the school was in Miami, a region that feels the effects of climate change first-hand. And second, was the opportunity to build a helicopter-based research vessel to his specifications, based on a prototype that he had developed earlier. That this helicopter could be expanded to ocean-ographic missions added to the appeal.  

H125 flying over Miami

Backed by Avissar’s fundraising and input, in 2015 the university unveiled an Airbus H125 dubbed the HOP (helicopter observation platform). The ‘flying laboratory’ would subsequently be customised with scientific sensors, cameras, and computers to collect environmental data close to the Earth’s continental and water surfaces, making it a first-of-its-kind tool.

The choice of a helicopter was intentional. Drones with the necessary payload are expensive, while fixed-wing planes are restricted when flying close to the Earth’s surface. Yet many climate processes happen there. “The further you go from the Earth’s surface, the less accurate and more contaminated the source of the process we want to understand,” says Avissar. 

Inch by inch, you measure those gases [near the surface] to assess their contribution to the atmosphere.

Roni AvissarDean at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science

Able to hover, fly at low speeds, or race ahead at 140 knots, the helicopter’s strength is in making micro-observations.

That will be important in the type of research Avissar envisions. In collecting data at just a few feet above the ground or water, he hopes to observe climate processes at a rate of at least 20 times a second. “At a helicopter’s airspeed, the information you collect is on the order of a few inches,” says Avissar. 

Avissar hopes to answer more questions like this. Starting in April, the HOP will be used to study the effects of climate change on the Florida Everglades. The project will involve multiple observations, some using remote sensing such as cameras to monitor water levels and the health of vegetation, or in-situ observations measuring gases and heat exchange. 

Helicopter Observation Platform (HOP)

High Altitude Ice Crystals

A340 take-off after HAIC installation

In 2012, a four-year European field experiment was launched with multinational support to study the formation of ice crystals in clouds. Dubbed HAIC (High Altitude Ice Crystals), it was led by Airbus.

Its objective: provide manufacturers with a way to meet aeronautical regulations (ie numerical and testing capabilities), and develop technologies for ice particle detection and awareness on commercial aircraft. 

Alice Calmels and Delphine Leroy

Icing occurs when a plane flies through clouds with supercooled water droplets that freeze on contact, causing anything from reduced visibility to increased drag and loss of lift if the aircraft is unprotected. Since the 1990s, scientists have begun to study another type of icing: the presence of large amounts of ice particles in clouds.

“We have questions as to how ice crystals grow,” says Delphine Leroy, researcher at CNRS-LaMP (Laboratoire de Météorologie Physique), the French national scientific research centre. “But one big unknown is how many will form in the environment and when.” 


images per second were recorded

In 137 flight hours in a SAFIRE Falcon 20 jet and 32 hours on an Airbus A340, the team collected data over Darwin, Australia; Cayenne, French Guyana and St Denis, Reunion Island, fitting the planes with sensors to measure cloud properties. 

Eric Defer, a researcher at CNRS-LA (Laboratoire d’Aérologie), collected data via satellite. While Leroy’s sensors flew through clouds, Defer used satellite observations to document the clouds around the aircraft and measure their properties to compare them with Leroy’s readings. 

Progress made on these technologies is very promising.

Alice CalmelsAirbus ice protection systems expert and technical director of the HAIC project

Leroy sees using the data to improve how the ice phase is represented in cloud models used for research, weather forecasting and climate predictions—such models would be key tools in studying the effect of pollution and how it can affect rain formation, for example.

Alice Calmels, Airbus ice protection systems expert and technical director of the HAIC project, is part of the team looking at putting the HAIC campaigns’ data to practical use in aircraft operation. “New technologies were flight-tested during the last HAIC campaign,” says Calmels. 

"The HAIC project has succeeded in increasing our knowledge on this particular concern, as well as in converting the results into products and services.”

Quick facts

  • HAIC project: launched in 2012 with the support of 34 partners from 11 European countries, and 5 partners from Australia, Canada and the US.
  • Supercooled water droplets: liquid water with a below-freezing ambient air temperature.
  • HOP H125: with a payload of up to 2,500 lbs, the H125 can remain airborne for nearly four hours without refuelling.

Heather Couthaud