How Albatrosses fly such vast distances - tacking upwind

Woods Hole Oceanographic Institution discovers Albatrosses tack upwind



'I have a simple model that explains the basic physics of what albatrosses do,' says Richardson, a scientist emeritus at WHOI, who, in addition to his primary career in studying ocean currents, has also piloted gliders. The key, he says, is the bird’s ability to balance the kinetic energy gained in soaring with the energy lost from drag.

WHOI Graphic Services

In a paper published in the winter 2011 issue of the journal Progress in Oceanography, Richardson says that dynamic soaring using wind shear accounts for '80 to 90 percent of the total energy required for sustained soaring.' He explains that above ocean waves, winds blow in layers—near the surface, air-sea friction slows lower-level winds while winds blow faster at higher levels.


Richardson was particularly intrigued by how the birds could be doing this while flying into the wind, something he had observed from a ship in the South Atlantic Ocean. 'It’s been a mystery how they fly this way,' he said.

Heidi Richardson


It also explained the bird’s ability to seemingly fly upwind. To travel upwind, a sailor tacks into the wind. Richardson realized that albatrosses do the same thing. Using his model, he calculated that the bird tacks at about a 30-degree angle, 'like a sailboat.' 'They are using wind shear both ways,' he says. 'To climb up and dive down.' Using the model, he estimates that it takes a minimum wind speed of about seven knots for an albatross to soar.

In further describing this dynamic soaring, Richardson says what he has done is to refine previous models. While calculating that dynamic soaring accounts for the vast majority of energy for albatross flight, he says the remaining 10 to 20 percent comes from updrafts. 'It’s a simple model that explains what albatrosses do,' he said. 'It helps us understand how nature works.'

Beyond that, Richardson suggests that understanding albatross flight might help increase the speeds of radio-controlled gliders, or someday enable fleets of such gliders to be dispatched to measure oceans, he said.


