Science Post: Riometers, Photometers, Magnetometers, and SuperDARN

The broadband riometer array at Arrival Heights

So, last time I said that I'd start talking about some of the science I look after here at McMurdo. A-111 is a combined project involving, a riometer array, photometers, and a magnetometer. The riometer and photometer systems help study the process of energy transfer from the solar winds to the Earth's magnetosphere and ionosphere at high magnetic latitudes. The riometer array picks up galactic radio noise, which is assumed to be constant at any point in the celestial sphere. These radio signals are absorbed by ionized air, so fluctuations in signal intensity signal changes in the ionization level. These changes can be cause by solar UV and EUV radiation, galactic cosmic rays, solar flare protons, or aurora-associated energetic electrons. The data is process to isolate effects due to energetic particles. The photometers measure photo-emissions at two auroral wavelengths for correlation with the riometer data. Lastly, the magnetometer is used to study hydromagnetic wave phenomena in the magnetosphere. So, all of this is a long way of saying that this project studies aurora.

Checking the signal cables out to the riometer array

My responsibilities for this project include daily and monthly checks on equipment. Every day I check on the computer read-outs, to make sure that data is still being collected and transmitted off continent. Earlier this season, one of the computers failed which made for an exciting couple of weeks. However, Gil and Bob, two of the grantees on the project came down last week, bringing with them a replacement computer, and a brand new one. The new one is going to run in parallel with the other computers in the system, and if all goes well, it will completely replace the others next year when the group comes back. At the beginning of each month I also do a walking inspection of the signal cables and the riometer array up at Arrival Heights. And since I am "off station" I get to bring a buddy, or buddies, with me for safety and extra hands and eyes. We check the cables for wear, patching them with electrical tape if need be,  and check the riometer array for alignment, missing antenna arms, and damaged anchor/stabilization lines. It is a nice hike in good weather, and makes me pretty popular with people who want to get off station for a couple of hours.

The imaging riometer antenna.

One of the other projects I support is the Super Dual Auroral Radar Network, or SuperDARN for short. The McMurdo SuperDARN is part of a network of 32  radar systems looking into the polar regions of the Earth. The radars measure the position and velocity of plasma irregularities in Earth's ionosphere. The movement of these irregularities responds to energy coupled into the auroral regions from the solar wind and magnetosphere. This means that SuperDARN provides information regarding the Earth's interaction with the space environment.

In the SuperDARN antenna field

Every week I do a drive by of the antenna field, checking to see that the antennae are still standing and that the anchor lines are still attached. If we ever get big storms, I'll walk the field to do a closer inspection, which I did at the end of last month, when we had our one Condition 2 day so far this summer. Everything was still in good shape.

Melt pools, now with actual liquid

 Outside of science a lot has been happening. We celebrated Thanksgiving almost a week early, at the the food was great. We also got a two day weekend for the occasion, which is always exciting. There were a number of activities to over the weekend, including a Turkey Trot 5K out to Scott Base and back. That included an uphill almost the entire first half and 15 knot winds blowing in the wrong direction on the way out, and in sort of the right direction for the way back in. The weather has gotten really nice. We hit 35F earlier this week, which isn't unusual for this time of year, but temperatures in the 20s are more normal. With the warmer temperatures, we've also officially entered mud season. The roads are kind of a mess in places, and we have little rivers running all over the place. On my last pressure ridge trip, we saw four seals, three of them up close.

A pregnant seal right off the flag line.

One day last week, after finishing up soccer, we came outside to be treated to a pretty impressive display of fata morgana, which is a type of superior mirage.

Fata morgana across the Sound.

From what I've heard, this phenomenon cause a lot of trouble to the early explorers of Antarctica. They would come outside one day to see these huge cliffs across the way, and decide they wanted nothing to do with that. Then they'd come back a while later and the cliffs would be gone. The name itself is derived from the Latin for fairy and from Morgan le Fey, the sorceress from Arthurian legend. It's pretty cool.
And I got a package from home, which is always very exciting.