Cruising thousands of feet above the Arctic through a raging storm isn’t the most congenial research environment – unless you are part of Alaska’s flying laboratory of weather scientists. Sabrina Reichert investigates.
Hurricanes are typically thought of as tropical storms, but similar phenomena often affect Arctic locations such as Alaska. The prevalence of “winter ocean storms with hurricaneforce winds”, specifies Dr Paul Chang, a chief scientist on the airborne ‘Hurricane Hunters’ project, provides ample opportunity to better characterise these weather systems and their atmospheric dynamics.
Their work is aided by extremely high-tech monitoring systems aboard two highly capable aircraft: the Gulfstream IV-SP (G-IV) and the P-3 Orion, both of which depart from Ted Stevens International Airport in Anchorage. Both aircraft are deployed to study not just hurricane geohazards, but also the changes that occur within the frozen tundra cryosphere and their impacts on native villages and mammalian wildlife; with this in mind, the Hurricane Hunters spend around a month each year in Alaska to focus on the Arctic climate and life systems.
Both aircraft are perfectly suited to Alaska’s aviation conditions, with capabilities such as high-altitude high-speed cruising, durability and the load capacity necessary to carry the team’s arsenal of data acquisition and processing equipment. Indeed, TV producer John Bonny, who spent four seasons documenting the team’s endeavours for the US Smithsonian Channel, describes the P-3 Orion aircraft, with over 100 sensors on board, as a ‘flying laboratory’.
Onboard equipment includes the so-called GPS dropwindsondes – ‘sonde’ refers to the attached radio transmitter, ‘dropwind’ to the mechanism of deployment. These parachute down from the plane post-deployment to capture high-altitude data. Additional instrumentation includes a conically scanning dual frequency Doppler radar/scatterometer (IWRAP – Imaging Wind and Rain Airborne Profiler), to map steering currents that define the hurricane’s trajectory, and to measure wind and rain through the atmosphere and the winds at the ocean surface. To top this off, Chang and Dr Zorana Jelenak, co-principal investigator, install KaIA (Ka-band Interferometric Altimeter), and other Airborne eXpendable technology such as BathyThermographs, to define the surface topography of the study area.
These sophisticated modifications to the aircraft allow the team to conduct other surveys in addition to their Hurricane Hunters work. Bonny notes that one of the other missions flown during his time producing Ice Airport Alaska was a lowflying mission, with a flight deck of 500 feet above the terrain. The goal: measure the water content inside the snow and ice to predict either drought or flooding post-thaw.
Other science goals that Chang pursues include calibration and validation of satellite data, and the formation of a better understanding of the fluid dynamics behind these hurricane-force storms: there is a highly complex air-sea interaction that occurs during these weather events, with a ‘decoupling’ that occurs when wind speed exceeds the friction threshold between ocean and atmosphere. Still, the work begins even before the flight to ensure both crew safety and the success of the mission.
The flight experience is, as Bonny and the pilots put it, “like being in a washing machine”
Prior to takeoff, the Hurricane Hunters will often consult with the National Weather Service, prepared as part of the NESDIS Ocean Winds Aircraft Experiment, for a weather and ice briefing. This presentation contains information on weather features such as approaching lowpressure systems, active storm cycles and other inclement weather patterns that could affect flight conditions. In addition, the presentation contains additional information on Instrument Flight Rules (IFR) and Marginal Visual Flight Rules (MVFR), flight level winds, sea ice, and volcano status where relevant (mostly for fieldwork in southern Alaska); this briefing informs the team’s understanding of both study conditions and flight safety.
The flight experience is, as Bonny and the pilots put it, “like being in a washing machine”. The turbulence of these severe weather events is intense, and while most aircraft try to avoid these weather systems, the Hurricane Hunters do the opposite. As a result, the production team had to make certain adjustments to their standard filming procedures to best accommodate the weather and the crew’s operations. For instance, the P-3 Orion has Turboprops, because a traditional jet engine isn’t responsive enough.
Another modification was the rig the production team built for the P3 Orion to mount their GoPros and 4K ‘Blackmagic’ cameras. They created an incredibly secure cockpit mount, Bonny recounts, which was so innovative that it even necessitated a sign-off from the FAA to be approved for flight. The rig held three cameras, one pointing to each pilot and another centre-facing wide-angle camera, all of which enabled the production team to collect both audio and video through a cord to a control centre of hard disks. These recordings were then matched to sync audio with video via a time code, and the process was aided by battery packs large enough to last 12-plus hours on each long flight.
An additional aspect of the tough weather conditions, apart from intense turbulence, was the extreme temperatures in northern Alaska. Ambient temperature on many of the winter filming days was down to -40?F just at ground level, with even colder temperatures with wind chill when airborne. Chang notes that, as capable as the P3 is at handling extreme weather with the load of scientific instrumentation, “it’s not a new plane”, and there are sometimes maintenancerelated delays that interrupt missions.
He and Jelenak pursue flight times with a window of overlap with satellites passing overhead, to calibrate their data acquisition. When there are maintenance and weather delays (such as freezing fog at Ted Stevens), the team may be forced to cancel a flight that will miss this critical window.
Ambient temperature on many of the winter filming days was down to -40?F just at ground level, with even colder temperatures with wind chill when airborne
Bonny recalls an instance of a GoPro being so cold that it could not turn on for more than a second, so he and his crew turned on the engine of one of their cars for 30 minutes to warm up the camera inside, and they strapped handwarmers to the case to keep it warm for some of the flight. There was no guarantee that the footage was ever going to survive, because the filming technology did not have a threshold for such extreme temperatures. Bonny says: “The environment is very limiting in terms of what you can achieve, in terms not of ambition but in terms of output.”
Ultimately, Bonny and his team’s goal was less about the pure science and more about telling the NOAA team’s and Alaska’s stories. To quote Bonny, “the filming itself felt like a real privilege”, with “crew that don’t even think twice about going on risky missions and carrying out their jobs” because of their passion for what they do. Chang describes his work in Alaska as a highly fun and worthwhile pursuit that he’s been involved in since the 1990s. “A lot of what we do to collect data today is for the purpose of making improvements tomorrow,” with a science question that keeps everyone coming back for more.
Sabrina Reichert is a graduate student at Jackson School of Geosciences, University of Texas Institute for Geophysics
