Long Day / Night

I am at the end of a very long day, or night, depending on how you want to call it. We left McMurdo at around 1:30 PM yesterday afternoon. The plan was to do unmanned aerial vehicle (UAV) flights through the afternoon and evening. If things were going well we’d keep going into the night. We got back to McMurdo around 6:30 AM. During that entire time at Pegasus we were only able to get in three flights. We were fighting a lack of wind the entire rest of the time. There were two times where we loaded up the van and drove onto the runway. We got out of the van, verified the winds were good to launch, went back into the van to do the pre-flight checklist, and when we went outside to launch there was not enough wind. During the first time that it happened, we stood with our faces into the wind for five minutes, ready to launch, and waiting for the winds to increase. I even have video of those five boring minutes of us standing and waiting (we were hoping to make a video of the launch).  The second time, around midnight, we launched the UAV but it did not have enough lift. Fortunately, John was able to do a controlled landing and there was no damage done to the UAV. We didn’t get another shot at a launching the UAV until 5:00 AM. The data from the three flights will likely be interesting and useful, however, the more flights we have the better. By the time we were done with the third flight, we decided it was time to return to McMurdo. I also had an appointment to do a Skype session with kindergarten class at 8:00 AM.

The reality is that such a scenario, as we had during the last 24 hours, is the life of field work, especially in Antarctica. Instead of doing flights every two hours as we had hoped, we did a total of three in 15 hours (6 hours in between the first two and 9 hours in between the last two). This experience was also very representative of our last 2 1/2 weeks since the accident. It has been a continual battle in getting enough wind. During other years, there have been WinFly field seasons where the scientists and contract workers have continually battled too much wind. You never know what you are going to get and how it will impact your field work. The key is you have to roll with whatever comes your way, and hopefully keep your sanity in the process. The second part is the trickiest.

Being out at Pegasus all night also allowed me to experience and see just how much the conditions have changed since I arrived 4 1/2 weeks ago. The temperature at Pegasus Airfield was a few degrees above 0F overnight. That is in comparison to the -40sF that we were experiencing 2 1/2 weeks ago. The length of the day is now around 14 hours and the sky never went completely dark. In fact, at about 3:00 AM there was a little aurora australis in the sky but because the sky was not fully dark, the aurora was difficult to see. 

The first priority for today (Thursday) is to get some sleep. We might go back this evening or delay until tomorrow afternoon and into the evening. Either way, we have concluded that we have one more attempt to get in a series of UAV flights. Saturday is reserved for packing the cargo, returning equipment/supplies, and cleaning the lab. Sunday is an off day for most everybody in town and Monday is the day I am scheduled to fly north to Christchurch to end the season. This WinFly field season is coming to a close very quickly.

A Week in McMurdo

Life in McMurdo, or anywhere in Antarctica for that matter, can make the days all blur together and suddenly a week goes by where you are not sure how it was spent. Each day runs into the next and oftentimes one day does not distinguish itself from others. With the six day work week in town there is little time for the weekends to be unique. Part of the reason for days blending together is that there is a fairly small area where you live and what you see every day becomes very repetitive. I look back at the last two weeks and it feels like they have flown by and it is difficult to believe that I am down to one week until I leave McMurdo. This past Saturday I tried to think through my week and I was confused on what we did on several days. John and I had to pool our memories to determine which days we flew the UAVs, which days we went out to Pegasus and did not fly, and which days we never left town. I thought people might enjoy the results as a snapshot into the day to day life of a little over a week in McMurdo.

Saturday - September 17:  
We returned to flying the UAVs after the accident that cut John's hand. We went out to Pegasus in the morning after breakfast and promptly crashed the UAV (SUMO2) twice, rendering it no longer able to fly after the second attempt. We went back to McMurdo to get the backup plane and returned to Pegasus by mid-afternoon. We got in a couple flights, the winds turned light and variable, and we returned back to McMurdo by mid evening feeling happy with the two completed flights. (The UAV is difficult to launch with no wind to help provide lift at takeoff.) I was also happy to make it back to town to go to a "birthday blowout" party hosted by the plumbing shop.

Sunday - September 18:
We had thoughts of flying for the day but were hesitant because the forecast was for light winds. We agreed to meet at noon and evaluate our options. Sundays are the one day off during the week in town so the meals are condensed to a brunch and dinner. I had brunch, John and I met in the lab, and we were uncertain of the winds so we decided to wait and see how they would respond. We ended up staying in town the whole day. I remember going to the gym and getting in a treadmill run that afternoon.

Monday - September 19:
For this day we decided to do some flights ranging from early evening to the early morning hours. I spent the beginning of the day getting some research done for a project back in Colorado. We had an early dinner (right after the Galley opened at 5:00PM) and then drove out to Pegasus. We were able get in two flights and then the winds went to light and variable. We waited a couple hours and then ended the night early realizing we were not going to get in anymore flights.

Tuesday - September 20:
The plan for the day was to switch to more of a daytime schedule. We left McMurdo around mid-morning to do flights from mid-morning until around dinner. The first UAV flight crashed because of a bad throw and the winds were too light. We had to go back to McMurdo, without a successful flight, in order to repair the UAV. We made it back in time for lunch and spent the remainder of the day doing other work and I got in another treadmill run at the gym.

Wednesday - September 21:
We weren't sure of our plans for the day but the forecast was calling for it to be windy at Pegasus. The forecast verified and there was Condition 2 weather at Pegasus, which meant it was too windy and too low of visibility at Pegasus to do any UAV flying. We spent the day in McMurdo getting other work done. I was able to get in my longest treadmill run of the season late that evening.

Thursday - September 22:
John had a Skype session in the morning with his daughter's elementary class. With that commitment we planned to do early afternoon to evening flights at Pegasus. We started to leave at 1:30 but did not get very far. We brought in our van to the vehicle maintenance facility to have the fluids topped off. They took care of the fluids and then decommissioned the van because it was leaking too much power steering fluid. It was not until 3:30 that we got a replacement van and were able to leave for Pegasus. The van problem was not much of a delay because we got to Pegasus and the winds were too light to fly. We waited at Pegasus for about four hours and determined the wind was not going to be increasing anytime soon. We decided to end the day and returned to McMurdo without any flights.

Friday - September 23:
Friday had a significant storm that was very well forecast. The storm verified with Condition 2 in McMurdo and Condition 1 at Pegasus Airfield. The weather stayed about the same the entire day. After a run of a few days of pushing the pace and getting nowhere, I decided to slow down and take it easy the first half of the day. I was able to do my laundry that morning. That evening I made it to Gallagher's (the one bar open during the winter) where it was Open Mic night. I was able to see some fantastic performances by some of the workers in McMurdo.

Saturday - September 24:
We decided to stick with the plan for flights from early afternoon through the evening hours. That allowed me to do another treadmill run in the morning. We left for Pegasus at noon and were treated with some near ideal winds to fly the UAV. We completed two flights back-to-back (we generally do flights every two hours). The winds were too light to fly when we wanted to do the third flight. We tried again an hour later with no change. We waited another hour and found the winds acceptable and completed a third flight. After the third flight, we concluded that the winds were likely going to be light for the rest of the night, we were happy to get in three good flights, and we decided it was best to return to McMurdo. We were back in McMurdo by mid-evening.

Sunday - September 25:
The forecast was for light winds throughout the day. We also had the weekly general science lecture in the evening. It was a rare day where we left the lab the night before with no plans to fly for the day. We also had daylight savings go into effect overnight. (While there is no need for daylight savings in Antarctica, McMurdo Station, South Pole, and most of the US Antarctic Program follows the time of Christchurch, New Zealand which switched to daylight savings.) I went to the non-denominational church service at the Chapel of the Snows and then the weekly brunch. Most of the afternoon was fairly quiet until late afternoon when I took some time to prepare for my portion of the science lecture. The evening was dinner and the science lecture, which went well.

By the end of the week I was able to remember that we had a couple days with a couple flights, a couple days with no flights due to no wind, and a couple days with no flights due to a storm. The difficult part was putting the days in order because it all seemed to blend together.

Slow Progress

I have previously commented that it is key with Antarctic field work to get the work done when you can because you don't know when you will have the next opportunity. Such an assessment of the situation has been proven during the past 10 days. We have had a very challenging, difficult, and at times frustrating last 10 days with minimal to no progress with the field work.

The difficulties started abruptly 10 days ago when we were about to start our third night of overnight flights. Our concerns at the start of the night were that it might have been too cold because the unmanned aerial vehicle (UAV) temperature sensor currently has a limit of -40F. At the surface we were well below that temperature but it might have increased quickly to above that temperature not far above the surface. In the end, we were never able to find out. On the first flight of that night the UAV propeller hit John's hand and resulted in two deep cuts. I was in the van monitoring the computer when he asked me to come back to help pick things up. I looked at his hand and it was obvious that we had to pack everything in the van and immediately return to McMurdo. We stopped in one building at Pegasus to find a first aid kit and were able to apply enough gauze and wrap to control the bleeding. From there, it was the 45 minute drive to McMurdo from Pegasus. It was an odd experience to call into the radio dispatch saying we were returning early and to please have medical ready when we arrive. John was handling everything extremely well so he did the radio calls while I drove. In the end, it was five stitches in one cut and four stitches in the other. Our night and the next few days were done for flying the UAVs. The weather was fairly poor for the next couple days so we didn't miss out on too much for opportunities to fly.

We returned to Pegasus four days after the accident. We came up with a new procedure. After the pre-flight checklist, John is on the RC and I throw the UAV for the launch. We are also now wearing cut-resistant gloves and safety glasses. For the first flight I throw SUMO-2 (the UAV we had been flying) and it immediately goes nose-up, stalls, goes nose-down, and crashes into the snow. Pieces of the SUMO scatter. Nothing was damaged so we put it back together and try it again. In the meantime, I am thinking "how did I mess up the throw, what should I have done differently". I throw it a second time and the UAV immediately goes nose-up, stalls, goes nose-down, and crashes into the snow. Pieces of the UAV scatter and this time SUMO-2 is not recoverable and we are done flying it. I'm feeling horrible trying to figure out what I am doing wrong. We go back to the passenger terminal (where we work at Pegasus) and we even watched the video that I took of a launch by John from the previous week. I throw the decimated SUMO-2 around to gain a sense of what I am doing wrong. I start to become convinced it is not me, it is the plane. I start to think that SUMO-2 was damaged in some unknown way during the accident with John's hand. It could be something as small as the motor/driveshaft being bent just a little and changing the thrust from balanced to nose-up or it could be in the avionics. We drive back to McMurdo to get SUMO-1 (a backup UAV). A sensor needed to be changed on SUMO-1 and scavenged from SUMO-2. The sensor is changed and we return to Pegasus. We were able to successfully launch SUMO-1 twice late that Saturday afternoon. I am now even more convinced it was SUMO-2 being damaged from the accident and not my throwing.

Unfortunately, that has not been the end of our run of difficulties. We have had a couple days of not enough wind where we did not even travel to Pegasus. There have also been a couple days of too much wind. Twice, including last night, we went out to Pegasus to reach the conclusion after hours of waiting that we were not going to see enough wind. On one day we did decide to launch the UAV, even though the wind was marginal. That was a bad move as the UAV crashed on launch with some damage, which has since been repaired. Yesterday, we were also delayed because they decommissioned our van due to a leak and we had to wait for a replacement. In total, we have gone out to Pegasus five days in the last 10 days since our run of successful flights at the beginning of the season. On each day we have returned earlier than anticipated and we have had a total of about four completed flights. There are 10 days remaining in our field deployment and we will likely stop flying a day or two before we are scheduled to leave. There is still a chance that we can get on another successful run of flights.

Q&A - Questions

The weather has warmed in McMurdo the last few days with temperatures generally in the positive single-digits to negative single-digits. There is a good chance that the real cold temperatures for the season are over. The sun is getting progressively higher and higher in the sky every day. McMurdo is now completely in the sun from late morning to late afternoon. We are approaching 12+ hours during the day with sunlight. The nights are turning more and more into long hours of twilight with only a few hours of complete darkness. The flying of the UAVs has been slow as of late with a couple setbacks last week. We will be going out this afternoon to try to get into a routine again with regular flights.

This post was originally motivated to be sent for teachers but I am opening it up to everybody. If you, or your students, have any questions about Antarctica and/or the experiences I am seeing during the field season, please send them to me. Later this week I’ll consolidate the questions that are sent to me and write a post providing answers, or attempts at answers, to the questions.

Condition 2

The United States Antarctic Program uses a weather classification system to identify when restrictions are put into place at a field camp or station. The classification systems is: Condition 3, Condition 2, and Condition 1. Condition 3 is normal weather conditions without any significant detrimental weather impacts, Condition 2 occurs with moderate weather presenting a concern, and Condition 1 indicates potentially hazardous weather for any form of travel.

The specifics are as follows:

• Condition 3:  Winds less than 48 knots; Visibility great than 1/4 mile; Wind chill warmer than -75F
• Condition 2:  Sustained winds between 48 and 55 knots; Visibility between 1/4 mile and 100 feet; Wind chill between -75F and -100F
• Condition 1:  Sustained winds greater than 55 knots; Visibility less than 100 feet; Wind chill colder than -100F

Only one of the three criteria needs to be met to push the weather into Condition 2 or Condition 1. My experience is that it is the visibility that is the driving factor. The weather conditions are also defined for nine regions in the area around McMurdo Station (e.g. McMurdo, Williams Field, Pegasus Field, Road to Pegasus).

Condition 2 presents restricted pedestrian traffic between buildings and limited vehicular traffic in an enclosed vehicle with required radio checkout at all times and locations. Condition 1 is the most limiting as everybody is confined to their current building or nearest shelter. I have never experienced Condition 1 in Antarctica. In fact, there have only been a few times where I have experienced Condition 2.

During the last two days we had a storm move through the region. For a few hours Thursday evening we went to Condition 2 in McMurdo. I had been watching the storm in the weather forecast model for a few days leading up to the actual storm. The fact that we went Condition 2 for a few hours made it a reasonable storm, although overall there was not much to the storm. About a week ago, we had Condition 2 weather on the drive back from Pegasus but we were the only ones on the road so it was not officially classified as Condition 2. I also experienced a Condition 2 storm at WAIS a year ago.

After a few days off from flying the UAVs, due to the weather and to rest, we are planning on returning to some morning to afternoon flights the next few days. I have also passed the midway point of my time in Antarctica, provided there are not significant delays in the flight back to Christchurch.

Limited visibility due to blowing snow and ice fog on the road going from Pegasus Airfield to McMurdo Station about a week ago.

Signs are placed throughout McMurdo indicating the weather condition. The weather condition is also indicated on the station webpage and a TV channel. This is me in front of the sign for this week's Condition 2.

Overnight Flights

One of the goals for the unmanned aerial vehicle (UAV) flights is to observe the atmosphere evolve over the course of a day. The lowest part of the Antarctic atmosphere is known for its frequent characteristic of the temperature being coldest near the surface and then increasing in temperature with height over the lowest few hundred feet. This characteristic is referred to as a temperature inversion because it is the inverse of the general condition of the temperature decreasing with increasing height (in the part of the atmosphere with all of the weather). The cooling at the surface is most pronounced during the nighttime hours when there is no heating from the sun. This means that one of the periods of day that we are interested in observing is during the overnight hours. This is when it is most expected to see such a temperature inversion and we are interested in how it changes during the nighttime hours. We completed UAV night flights this past Sunday evening through early Monday morning as well as the following overnight.

Flight path of the UAV in the early night sky. This was approximately a 12 second photograph.

The operation of the UAVs at night is not much different than during the day. The launching and landing of the UAV is the only tricky times during the flight. We do all of the pre-flight checkouts while remaining in the van. When it comes time to launch, John goes outside and I remain in the van to monitor the autopilot controls on the computer. Once the UAV is launched, it is actually easier to track the UAV at night because the lights on the UAV make it easier to identify in the nighttime sky. For the landing, it is key that John is able to make out the surface. With the light from the moon and white snow everywhere, it doesn't take much to see the surface clearly. If needed, I'll also turn on the headlights of the van to light up the surface for landing.

Time lapse photograph of the launch of the UAV at night. The lights are indicating different parts on the UAV.

Time lapse photograph of the flight of the UAV near the highest point of the profile. The UAV continues to fly in circles as it ascends and descends the flight path.

The flight path of the UAV as it is getting closer to the surface. Stargazers might be interested in noticing that that constellation in the center of the photo, just to the left of the UAV flight path, is the southern cross.

The temperatures in McMurdo were in the -30Fs when we went out to Pegasus Airfield Tuesday evening. That indicated that the temperatures were even colder at Pegasus. I placed my handheld thermometer out the window at one point during the drive and recorded an air temperature (not wind chill) of -56.7F. We stopped the van not long after that and I measured -54F. That sets a personal record for me that will be difficult to ever surpass.

Taking a moment to get outside and experience -54F air temperature. In my hand I am holding a small handheld weather station. The handheld weather station is reading -46F, which is about as cold as I could get in holding it still. Also, notice the snot-cicles on my nose (might need to zoom in to see).

We are into a routine with the UAV flights and we were able to complete 21 flights in five days. We are not anticipating to be flying over the next few days as some stormy weather is forecast to be moving through the area. In the future we will likely be doing flights from the early morning hours, before sunrise, through early afternoon to see the changes as the sun rises in the horizon.

A plot of temperatures from the vertical profiles made by the UAV on 11 September 2016. Notice the very cold temperatures near the surface and the dramatic increase in temperatures with increasing height right above the surface. This feature is referred to as a temperature inversion. It is also worthwhile noticing how the temperature profiles changed with approximately one hour and 45 minutes between each profile

Flying UAVs

The flying of the UAVs (unmanned aerial vehicles) is becoming somewhat commonplace for us. We have flown the UAVs at Pegasus on four of the last five days. One of the basic principles in Antarctic field work is the significance of doing field work when the weather and logistics allows. The temperatures continue to be cool in and near McMurdo Station but overall the weather has been good. As long as the weather remains good we will do our best to continue to collect observations with the SUMO (Small Unmanned Meteorological Observer) UAVs.

The passenger terminal at Pegasus Airfield. This building is being used as our base of operations for the UAV flights at Pegasus Airfield.

John in the back of the van preparing the UAV for flight and ready to launch the UAV.

John ready to throw the UAV in the air for the launch.

A successful launch of the UAV. At this point the UAV is being operated by John using the remote control. The control of the UAV is about to be transferred to the programmed flight plan and auto pilot control.

The routine of preparing for the flight, launching, monitoring the flight profile, and landing has become very routine. We have completed a total of 16 flights thus far. The procedure starts by loading the laptop, which has the ground control software, and the SUMO UAV into a full-size van. We are using the van as a “hanger”, or base, for the SUMO operations. We drive the van to/from the runway and it serves as a nice warm location from where we can monitor the flights. We don’t actually need a runway for the SUMO UAVs as they can take-off and land in a very small area but the runway provides a virtually unlimited space for the flights to be completed. I have been driving the van and John is typically in the back of the van with the SUMO. I drive to the same spot on the runway for each flight so that we can have uniformity in the observations. We go through a checklist verifying the settings and operation of both the ground control software and the SUMO. After the checklist is completed John gets out of the van with the SUMO and the remote control. He then increases the throttle, using the remote control, throws the SUMO, and the SUMO takes off. After the SUMO’s flight is stabilized, he activates the autopilot software and the SUMO then goes into a holding pattern with a circular flight path. Once the SUMO reaches the holding pattern, we activate the flight plan, which has the SUMO spiral up into the atmosphere, while briefly maintaining altitude at specified levels. The top of the profile is at approximately 1600 feet and then the SUMO spirals back to the holding pattern at about 160 feet above the surface. Throughout the journey, the SUMO is recording a collection of observations including temperature, relative humidity, pressure, and GPS position with ground speed. When the profile is completed, John takes control of the SUMO with the remote control and lands the plane, preferably as close to the van as possible. The entire flight lasts approximately 25-30 minutes. After the flight is completed, we drive back to the passenger terminal, which is serving as our base of operations at Pegasus. (The passenger terminal is a small portable building with a number of seats used for passengers to wait to board northbound flights to Christchurch. Since there are no intercontinental flights during WinFly the passenger terminal is not currently being used.) John downloads the data with the SUMO observations, starts re-charging the SUMO battery, and does a preliminary analysis of the data. Approximately an hour later, we repeat the process by launching the SUMO to capture another profile. The goal of the observations is to assess how the lowest part of the atmosphere evolves over time. Our early experiences have us completing four to five flights in a day lasting 8-10 hours. We also have the commute between McMurdo and Pegasus, which takes about 40 minutes each way. Over the last two days we have shifted to overnight flights to better understand the changes in the lowest part of the atmosphere with no influence from the sun. I’ll write another post about the nighttime flights in the near future.

Monitoring the flight on the laptop using the Ground Control Software. The UAV flies is a continuous circular pattern is it flies to the vertical profile to take meteorological observations of the atmosphere. 

John getting ready to take control of the UAV with the remote control and bring it in for a landing.

The UAV coming in for a land with Mount Discovery in the background.

The UAV immediately after landing on the runway at Pegasus Field.

Me holding the UAV to provide some context for the size of the plane.

There is not too much else to report from McMurdo. The temperatures remain cool with lows around -30F and highs around -20F. Sunday (yesterday) was the “weekend” for most all of the contract workers. Scientists generally work our own hours and for us it included another day of flying the UAVs at Pegasus.

UAV Flights at Pegasus Field

The good news is that we have been able to do some flying of the unmanned aerial vehicles (UAVs) this week. The calm to light winds continued on Monday and Tuesday negating any chance for us to fly the UAVs. On Wednesday we were able to do three UAV flights and on Thursday we did four. Soon, I will write a post focused on explaining the UAV flights, including photos, from pre-flight, to take-off, and ending with the landing. These initial flights have been focused on doing some initial trials with the UAVs, refining our system for handling the flights at Pegasus, and working on the data collection and analysis process. Each flight lasts about 15-25 minutes and the UAV climbs to an altitude of approximately 1600 feet. We decided to take yesterday off from flying the UAVs to concentrate on taking an initial closer look at the data and for catching up in other areas of research and life around town. The plan is to do some UAV flights later today and tomorrow.

Looking back towards Ross Island and McMurdo Station from Pegasus Airfield. The mountain in the background is Mt. Erebus.

Sunset over the Ross Ice Shelf as viewed from Pegasus Runway.

The cold air has remained in the region for all of the past week. The temperatures in McMurdo have generally been lows around -30F and highs around -20F. Pegasus Airfield, located on the ice shelf, has generally colder temperatures and we have been experiencing temperatures around -40F at Pegasus. The wind in McMurdo has been fairly strong for the last couple days providing some of the first really biting cold conditions that we have experienced on this trip.

I have mentioned a few times that the UAV flights are being conducted at Pegasus Field. Pegasus Field is a glacier ice runway with approximately 4 inches of compacted snow on top of the ice. The primary purpose of Pegasus Field is to land wheeled aircraft for intercontinental flights between McMurdo and Christchurch, New Zealand. The wheeled aircraft (such as a C-17, a wheeled C-130, an Airbus, etc.) provide considerably more capacity for cargo and passenger transport than a skied LC-130 airplane, which can land on snow. Pegasus is located 18 miles by road from McMurdo. The first four miles are on Ross Island and the next 14 miles are on a snow road on the Ross Ice Shelf. The Ross Ice Shelf is a permanent ice shelf over water that is hundreds of feet thick. This is in contrast to the sea ice, which is also located around a part of Ross Island, that is made up of primarily annual ice that forms and is broken up each year. Pegasus is one of three runways that are used for McMurdo Station. Williams Field has been around the longest and it is a ski-way on snow that can only land ski-equipped airplanes. The third runway, Phoenix, is in the process of being constructed through a new technique of compacting snow to a sufficiently hard density to allow wheeled aircraft to land. The plans are for Phoenix to be certified for operation before the end of the main body season in February.

Some of the buildings on skis at Pegasus Airfield. The white trailer is the generator for Pegasus. The orange building in the center is used to store "do not freeze" cargo for flights to/from New Zealand and the orange building on the right is for the fire station at Pegasus.

The start of the 18 mile Pegasus road to McMurdo Station.

Not too much else has been happening with my life in McMurdo. My experiences with past trips is that this two-week point is usually a transition time and includes a bit of a lull. I have now been away from home for three weeks, the field work is still early and not much has been accomplished, and I am still slowly getting to know people in town. We will be here for about another 3 1/2 weeks. I am confident that those 3+ weeks will go very quickly.

View of Hut Point Peninsula and Scott Base extending to the southwest from Ross Island. The picture is taken about two hours after sunset.

New Experiences

I have not written much lately because there has not been much to say. That changed in the last 36 hours, but I'll get to that. The rule of thumb is that it takes a week from when you arrive in McMurdo until you are ready to go into the field. Lately, it seems that delay has been decreasing but it still takes several days. Much of that time is spent in trainings, meetings, and briefings. There is also the time it takes to unpack the cargo and to prepare the equipment for the field. One of our last tasks on our todo list was to make a visit to Pegasus Field to get a tour of the facilities and decide on how we want things set up at Pegasus. We visited Pegasus on Thursday and had the hopes to do our initial UAV trial flights on Friday. The weather was poor Friday morning with light snow and limited visibility. On Saturday, we made it out to Pegasus with hardly a cloud in the sky. However, this time we had no winds and the UAVs require a little wind in order to launch the plane into flight. Sundays are typically off days but we were planning on doing the trial flights today. Those plans were scrapped due to once again having limited to no winds at Pegasus. The latest is that we will get in the flights tomorrow (Monday).

One of the highlights from the last couple days has been finally getting some cold temperatures. The first week of WinFly has been about as warm, if not warmer, than my first week of the field season late last October. The temperature in McMurdo started decreasing Thursday night and into Friday. The temperature around noon on Friday was -18F. I estimated that we'd have temperatures around -28F at Pegasus, where it is generally colder. Not long before leaving for the drive out to Pegasus, I checked the observations at the Willie Field automatic weather station (AWS) and the temperature had dropped 15F in the previous hour down to -42F. (Willie Field AWS is located along the drive to Pegasus.) This was now some seriously cold air and a strong contrast to the temperature in McMurdo. As we were driving to Pegasus, we drove by the Willie Field AWS and John held a Kestrel (a small handheld weather station) out the window and observed a temperature of -47F. We immediately pulled the van over to get out, experience the cold, and to take pictures of the moment. This temperature crushed my previous all-time personal cold temperature from when I was growing up in Minnesota. It was also extremely odd because I can honestly say it didn't feel crazy cold. We are confident with the temperature being in the -40Fs as we measured it multiple times and with four different instruments. The best guess why it didn't seem so cold was because we were fully bundled in our extreme cold weather clothing, there was no wind, and the sun was up and shining on us, albeit minimally. We returned to McMurdo about five hours later and the temperature was now around mid -20F. For the last day the temperatures have remained that cold and this evening the temperature was around -30F. The winds have been light to calm the last day so it has felt very cold but bearable when outside.

Standing outside in -47F on the Pegasus Road to experience a new personal all-time record cold temperature.

The sun above Ross Island when we pulled over to experience the -47F temperatures. It is actually very bright out at the time. The darker colors are from taking the picture with the camera directly pointed at the sun. 

Measuring the -47F temperature with the Kestrel handheld weather station. It was odd but the -47F did not feel that extremely cold. The cold temperatures in McMurdo the last day have felt cold.

In addition to the cold temperatures we have also been able to experience several other great outdoor sights. The first, and most basic, is that we saw the sun for the first time on Saturday during out drive to Pegasus. McMurdo is located on the south side of Ross Island. Because it is on the south side, and due to the low angle of the sun, McMurdo has been in the shadow of Ross Island whenever the sun has been up since the first sunrise two weeks ago. McMurdo will soon start seeing the sun as the sun gets progressively higher in the sky. The drive out to Pegasus allowed us to get out of McMurdo and out of the shadow. We were able to see the sun for the first time just as we were about to drive onto the snow road. We decided to capture the moment and we pulled the van over to take pictures. Throughout the afternoon I continued to take pictures of the sun to capture the low angle of the sun.

McMurdo Station and sea ice in front of McMurdo in the shadow of Ross Island due to the low sun angle.

The higher parts of McMurdo are starting to come out of the shadow and see the sun.

The first time we have seen the sun on this trip. The sun is low in the horizon but above Ross Island. Mt. Erebus, in the center of the picture, is an active volcano and it is emitted some steam.

Later Saturday evening, John went outside and he came back into the lab to let me know that the aurora australis (southern lights) were out in the night sky. The aurora were present, although a little weak and they came and went fairly quickly. I am hoping for a better display of aurora australis in the next couple weeks, especially when we are doing the night flights at Pegasus. Then this afternoon we were able to see nacreous clouds. Nacreous clouds, also known as polar stratospheric clouds (PSCs), are clouds in the stratosphere, above the level of the clouds that make up the weather. The PSCs require extremely cold temperatures to form, which is why they are a feature in the polar regions, and are typically illuminated by the sun shortly after sunset or before sunrise. The clouds, sometimes referred to as mother-of-pearl clouds, have a milky-white appearance and often include iridescent colors. The clouds that we saw today were fairly small and occurred before sunset. I took a few pictures of the nacreous clouds and I am hoping for a more impressive display before I leave the first week in October.

Nacreous clouds (also referred to as polar stratospheric clouds) in the sky shortly before sunset. 

Another photo of the nacreous clouds. Notice the distinct iridescent color of the clouds.

In the end, we are still waiting to do our initial trial flights with the UAVs but in the meantime we have been able to see and experience some of the features that make the WinFly season in McMurdo a special adventure.

A photo of Observation Hill near sunset on a Sunday afternoon. Notice all of the red dots near the top, which are the "big red" parkas that most everybody wears. Hiking Obs Hill is a common recreation activity, especially on beautiful days.