As I mentioned in a previous blog post, one of the things that I’m doing in Antarctica on this trip (aside from waiting for helicopter and Twin Otter flight time to visit automatic weather stations) is flying small remote controlled (RC) planes known as Small Unmanned Aerial Observers (SUMOs). On Sunday we did our second set of flights with the SUMOs. The SUMO flights are going well and we are collecting some interesting data. Here is a plot of the temperature profiles we measured with the SUMOs over the lowest 1 km (about 3000 feet) of the atmosphere on the last two Sundays (feel free to skip the following semi-technical discussion and scroll down for some photos and a video of our flights).
The green line is the temperature profile we observed two Sundays ago and this showed temperatures decreasing with height over the lowest 800 m of the atmosphere. The temperature profiles from this past Sunday (blue and red lines) show the opposite case, with temperature getting warmer as you move up from the surface to a height of 200 m. The temperature measurements for the blue line were made around 8:30 on Sunday morning and the temperature measurements for the red line were made around 1PM on Sunday afternoon. You’ll notice that the red line is shifted to the right of the blue line indicating that the air temperature increased over this time period. It is these changes in temperature that we want to measure because this tells us how much energy the atmosphere is gaining from the ground. In this case the shift in temperature indicates that the ground was giving up about 20 Watts of energy per square meter. This is about the amount of energy given off by a compact fluorescent light bulb so you can imagine that the atmosphere is “feeling” the heat from a grid of light bulbs spaced 3 feet apart across the snowy Antarctic landscape. This energy, of course, comes from the sunlight that the ground is absorbing.
The change in temperature between the red and purple lines indicates little energy being added to the atmosphere but the change in shape of the lines from red to purple indicates that the atmosphere became more well mixed due to increasing winds. By looking at profiles like this we can better understand the processes that control how the atmosphere behaves and use this information to test and improve the computer models we use to forecast the weather.
Now for the fun part of our work – here are some photos of the SUMOs in action. The first three photos were taken by Alice DuVivier, a graduate student in my research group, that is helping me with my work in Antarctica.
To the launch the SUMO we start the engine and then give it a good strong throw. Once I let go of the plane I take control of it with the remote control I’m holding in my right hand, the same way any RC plane would be controlled. We can also set the plane to launch on autopilot, but it is more fun to do it manually.
In this picture Lee Welhouse (from the University of Wisconsin) and myself are watching the SUMO execute its preprogrammed flight plan (the SUMO is in the top right corner of the picture).
Here I am watching the SUMO fly from a more comfortable position in the bed of a pickup truck. The plane will fly for 20 to 30 minutes, most of this being straight overhead. It doesn’t take long to realize that it is really uncomfortable to stare up into the sky for 20 or 30 minutes watching the plane so I thought it made sense to make myself comfortable. Now, if I could only do this on a beach in Hawaii instead of the vast snowfields of Antarctica. Actually, given my love of cold weather I’ll take the Antarctic flights over Hawaii any day.
Here is what I see when I stare up into the sky. As the SUMO climbs to 3000 feet it becomes just a tiny dot which can be hard to see, but we always try to have at least one person keep an eye on it at all times during the flight.
Finally, here is some video of a SUMO launch and then landing. Alice shot these videos and did a better job following a small, fast moving dot through the sky than I would have been able to. As you can see in this video the SUMO lands on its belly since it doesn’t have landing gear.
Thanks for reading.