We’re changing from the summer to the winter season at McMurdo. Besides the unique changes in sunlight, slowly changing from 24 hour sunlight to 24 hour darkness, the transition is also visible in the vastly decreased population and the quality of the data we can collect with the lidar systems.

The station population drops by more than 80% in the winter season. Though there are still 2 flights scheduled to leave, the majority of the population has already left. Mealtimes in the galley are far emptier than they were in mid February. There are far fewer events scheduled outside of work. Each department is operating with a skeleton crew. Despite all this, the sense of community is far greater. With only ~250 people on station, everyone becomes a familiar face.

Another important factor in the changing of the seasons is the quality of the data we get with our Lidar systems. During the daytime, since the background sunlight is so bright, we have strong interference filters and an etalon (used in the Fe systems) or Faraday oven (used in STAR) to block out most of the light coming in. During the nighttime, we’re able to change the interference filter to one that lets in more light and remove the etalon and Faraday oven entirely. This means that we are able to capture much higher quality data, with STAR Rayleigh photon counts jumping from around 80,000 in the daytime to around 360,000 in the nighttime! Right now, Jess has to switch the systems back and forth between daytime and nighttime as the sun rises and sets (a stressful process that has to be done entirely in the dark), but by this time next month we should be entirely in nighttime configuration.

Above: McMurdo at night. Unfortunately, no data could be gathered due to the cloud cover on this night.