On the Ice

Ferrell AWS and Weather Cancellations

Back on 6 February, Lee and I finished our helo work for the season with our visit to Ferrell AWS. Earlier, we thought we had finished the helo work at Ferrell, but we’ve had difficulty with the freewave transmissions there. It seems as if that spot is a dead zone for VHF (very high frequency) transmissions, which are what freewave uses. When we landed, our helo pilot was trying to contact McMurdo via VHF radio but was unable to, even though he could see the repeater he was aiming for. This seems to be exactly what is happening to us with our freewave transmissions to White Island!

We want the Ferrell observations to be available realtime, so the purpose of our trip back was to reinstall the Argos antenna we had removed earlier this year. Lee, Jonathan Thom back in Madison, and I worked up a way to have both freewave and Argos transmissions at one station the day before we flew. It was all very last-minute, but fortunately it ended up working out.

Ferrell AWS, with freewave and Argos transmissions installed (the white vertical pipe is the Argos antenna)

Ferrell AWS, with freewave and Argos transmissions installed (the white vertical pipe is the Argos antenna)

One reason we were able to get out to Ferrell by helo on such short notice is because our fixed wing flights have been getting canceled due to weather. It’s tough when the weather here in McMurdo is good, but out on the ice shelf it’s too cloudy to land. We look out the window and think, how the heck aren’t we flying? But Antarctica is a big place.

The past couple days, we’ve been able to see (and feel) exactly why we’ve been canceled. There is a storm just north of us that is producing very heavy winds in our area. One night, the winds were whipping up the open sea water onshore. I don’t think the couple pictures I took did them justice.

Big waves at McMurdo

Big waves at McMurdo

The winds have been too strong for planes to take off, and not just for the smaller, Twin Otter planes. Even off-continent, redeployment LC-130 flights are being canceled. Some of our friends in other groups were scheduled to leave the ice yesterday but were canceled due to the winds. Their departure date has been bumped back a few days, as flights that were supposed to leave today (yes, they got canceled too) were full of passengers with higher priority to depart.

Now we sit and wait for the weather to clear in McMurdo. This downtime does give us the opportunity to start packing away our gear for the winter. Hopefully Monday will bring clear skies and calm winds so we can service at least one more AWS by Otter.

Cheers

Dave

PHOTO UPDATE!

It’s started to snow in McMurdo…

The view of the Chalet from Crary, just outside our lab. Definitely a no-fly day.

The view of the Chalet from Crary, just outside our lab. Definitely a no-fly day.

An update on the weather, from the McMurdo intranet homepage:

The weather in McMurdo and surrounding area. Condition 3 is good weather, Condition 2 is worse and Condition 1 is the worst. No outside travel is permitted in Condition 1 weather.

The weather in McMurdo and surrounding area. Condition 3 is good weather, Condition 2 is worse and Condition 1 is the worst. No outside travel is permitted in Condition 1 weather.

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We got to Margaret AWS!

Lee and I took the Otter to Margaret AWS today, Monday 3 February. This station was installed in 2008 and had never been visited since. We knew that it was due to be raised, for two reasons:

One, with stations that we’ve installed on snow, it is almost always the case that there is snow accumulation, by precipitation and/or blow and drifting. The amount of accumulation depends on the location; some stations can get up to a few feet each year, and some don’t get any. If we know approximately how much snow an area gets a year, we can estimate how often we need to visit a station to raise it given the height of the instrumentation.

Two, the ADG (Acoustic Depth Gauge) instrument we have on Margaret recorded a height of about a half meter (1.5 feet) above the surface a few months ago. Many of our stations have this instrument, and it is a good way of knowing exactly how close the instruments are to getting buried. The ADG sends a pulse of sound waves towards the snow surface and measures the time it takes for that pulse to bounce back and reach the sensor. The longer the pulse takes, the higher the ADG is off the ground.

Knowing that we have to raise the station is half the battle. The tricky part is actually getting there (especially in Margaret’s case). It is by Roosevelt Island, on the Ross Ice Shelf about 500 km (310 miles) due east of McMurdo (a 2.5 hour flight). In this region, low cloud cover occurs often and in abundance (my previous blog post touched on this, when we visited the WISSARD fuel cache). I don’t know how many times we’ve been scheduled to go to Margaret this season and got canceled due to weather, flying somewhere else instead. We were pleasantly surprised to hear that Margaret was a go today. We flew across the shelf (a pretty boring flight, scenery-wise) and arrived at the station to be greeted by clear skies overhead.

Margaret AWS, upon arrival

Margaret AWS, upon arrival

The ADG is the instrument on the lowest “arm” that extends to the left at the bottom of the station. It was indeed low, as we expected, so we got to work right away on preparing everything to be raised.

We weren’t sure whether we should try to install a 7-foot or a 10-foot tower section to raise the station, so we brought both and made a game-time decision. We determined that the tower was tall enough to only warrant a 7-foot tower section. We felt that the 10-footer would have been too tall and that station may not have remained stable.

Unfortunately, the 7-foot tower section wouldn’t fit on top of Margaret. One, or both, of the tower sections was slightly skewed such that we could only fit 2 of the 3 poles of the tower section on at one time. After a few minutes struggling with it, Lee and I decided to give up on that and raise the instrumentation on Margaret’s current tower section. We probably won’t be able to wait 5 years until the next visit, but the instruments should be high enough for a few years’ time.

Margaret AWS, after we raised the instruments

Margaret AWS, after we raised the instruments

Things didn’t go exactly as planned, but we were happy to get the instruments raised and have a successful trip to Margaret. We don’t take any flights to that region for granted!

An update on life in McMurdo:

The population has increased a bit in the past week, and ships have been in and out of the port. Now, the vessel is in town. For the next week, people in town are working tirelessly to unload the cargo from the vessel to supply McMurdo with food and other vitals for the next year. Once that’s all unloaded, cargo from McMurdo that needs to be shipped back to the US gets loaded on. This includes everything from science equipment to food waste. As you may imagine, it is a long operation. The weather is also starting to cool down here. Highs have mostly been in the low 20’s, and winds are starting to increase. This past Saturday night, it even snowed. It was fairly heavy for a bit too. It’s actually starting to feel like Antarctica again!

"McMurdo Station Antarctica," the Vessel, and snow-capped Hut Point behind it.

“McMurdo Station Antarctica,” the Vessel, and snow-capped Hut Point behind it.

Cheers!

Dave

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An interesting way to reach Sabrina AWS

The Twin Otter work continued on Wednesday 29 January, as Lee and I were scheduled to reinstall Tom AWS, the one we had removed on 24 January. This AWS was to be moved to a new location. In our communication with the Otter pilots and flight coordinators, we had been referring to this new site as “New Tom AWS.” As Lee, Melissa, John and I were discussing this Tuesday night, Melissa came up with the idea to rename the station Emma AWS, after her and Tom’s 1-year-old daughter (Tom AWS was named after Melissa’s husband). We talked it over with the rest of the AWS crew back in Madison and determined that the new location of the station was far enough from the original to warrant a new station name, as it would probably show some unique weather to the original.

So on Wednesday morning, Lee and I shuttled out to Pegasus. We took off at about 9:30 am. Our first destination was the WISSARD fuel cache on the far side of the Ross Ice Shelf from McMurdo. The fuel here is meant for flights like ours: a long journey to and from McMurdo that couldn’t be made without refueling. This area of the Ross Ice Shelf is notorious for having bad flying weather, typically in the form of low clouds and fog. This is exactly how it was when we landed.

The edge of the low clouds and  fog outside WISSARD

The edge of the low clouds and fog outside WISSARD

These clouds make it very difficult, if not impossible, to see the snow surface when landing. Instead of risking that dangerous landing, we flew past the edge of the cloud bank and landed in clear skies, then taxied to WISSARD for about 5 miles. That’s a long way to taxi, but it’s much safer than the alternative. When we arrived, there wasn’t much to see.

Tanks of fuel at the WISSARD fuel cache

Tanks of fuel at the WISSARD fuel cache

Of course, there is usually more to see than initially meets the eye. As we were filling the plane up with fuel, I was taking in the foggy landscape. The sun was dulled by the clouds, and the sky and ground almost blended into each other. Looking away from the sun, the clouds were thinned out a bit, and I could see some of the sky. Looking exactly 180 degrees away from the sun, I saw the faintest of fogbows.

The very faint fogbow. I used a slight image enhancement to accentuate the feature, as it was difficult to capture on camera

The very faint fogbow. I used a slight image enhancement to accentuate the feature, as it was difficult to capture on camera

We departed the cache and headed for the coordinates where we thought Emma AWS was to be installed. As we were flying, Lee and I noticed that we had started going over the Transantarctic Mountain range, rather than staying over the ice shelf and flying along the mountains. We thought this was weird, but put this thought aside and enjoyed the scenery.

It was just as breathtaking as it was when we flew over them after we removed Tom AWS.

The Transantarctic Mountains

The Transantarctic Mountains

We flew along a glacier valley and reached an area that had some flat fields of snow, indicating a potential landing sight. The pilots did some investigating before landing the plane for good, though. Since this was a sight that had no records of being landed in before, it was important to determine the characteristics of the snow surface. As we circled the area several times, we noticed some spots that obviously had crevasses; these areas are way too dangerous to land on. There was an area that appeared to be crevasse-free, but the snow surface still needed to be characterized. To do this, the pilots dragged the skis of the Otter along the surface. This allowed them to get a feel for how the Otter reacted to the snow and see what the tracks looked like.

The open field of snow and the ski-marks from the Otter

The open field of snow and the ski-marks from the Otter

After a couple ski-drags and a few more fly-arounds, we all decided that this wasn’t a safe place to land. Though that field we were testing may have been crevasse-free, the snow was far too soft. On our last ski-drag test, we noticed the Otter start to sink too deep into the snow as we slowed down. It may have been very difficult to take off again had we come to a complete stop and did a couple hours of work.

We turned around and headed back out to the ice shelf. Fortunately, Lee and I were prepared to do some planned work at Sabrina. The wind propeller wasn’t functioning, so we were going to replace it.

Upon arrival at Sabrina, it was pretty obvious why the wind propeller wasn’t functioning.

Sabrina AWS upon arrival. The wind propeller and nose cone had broken completely off.

Sabrina AWS upon arrival. The wind propeller and nose cone had broken completely off.

In addition to repairing the anemometer, we raised the lowest temperature sensor and replaced the data card.

The updated Sabrina AWS

The updated Sabrina AWS

We were on the ground at Sabrina for about an hour, and quickly got on the Otter and departed for the 3 hour flight back to McMurdo. It was a long, stressful day. It turned out that we had the coordinates for Emma AWS wrong by one degree latitude. It sounds insignificant, but it was the difference between landing on the sturdy, flat Ross Ice Shelf and attempting a landing on soft Transantarctic Mountain snow. There are two consolations to this mix-up: we were able to get to Sabrina AWS, and we still have just over a week’s time to get back out and install Emma AWS.

An Antarctic field season never ceases to surprise!

Cheers

Dave

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The Improbable Twin Otter flight to Tall Tower! AWS

On Tuesday 28 January Lee, myself, and two riggers (Andrew and Emily) did something that I thought only happened in fairy tales. We took a Twin Otter out to Alexander Tall Tower! AWS. Now, an Otter had already been out there to pick up Ben the Kiwi. No way, I thought, was there a chance that the weather would cooperate enough to get us out there a second time in the same season. Sure enough…..

The much talked about, seldom visited Alexander Tall Tower!

The much talked about, seldom visited Alexander Tall Tower!

Our goal was to have the riggers raise the lowest three levels of instrumentation, while Lee and I would raise the power system by digging it out and reinstalling it back on the surface. You may be thinking, “Why do the instruments need raising? It’s a tall tower (100 feet at initial install, now about 90 feet) so the instruments must be high enough from the surface.” You would be partly correct. There are 6 levels of instrumentation. Referring to the picture above, each of the horizontal bars is a level of instrumentation. The top three are pretty high above the surface, but the bottom three are bunched near the surface and are at a higher risk of getting buried. The riggers did a great job raising these, saving them from the wispy grasp of blowing snow for at least another year.

The lowest three levels of instrumentation, after being raised

The lowest three levels of instrumentation, after being raised

Lee and I had our work cut out for us. The power station was installed three years ago, and hadn’t been raised since. There is about 1.5 feet of snow accumulation each year at Tall Tower!, so the bottom of the station was 4.5 feet deep plus the amount it was buried upon installation, which could have been a few feet. We needed to dig 8 feet down!

The power system. We had already started digging a bit.

The power system. We had already started digging a bit.

The things we needed to dig out:
The solar panel framework
Three guy wires with deadmen anchors
Battery box
Cable connecting the power system to the tower

Our first plan of attack was to dig out the battery box(es). We weren’t sure whether there were one or two. The top few feet of snow was fairly powdery and easy to shovel. After that layer, the snow became more compacted. The tricky part was around 5 or 6 feet down, when we ran into a layer of ice.

Eye-level view from the first pit I dug. The surface is at Lee's waist.

Eye-level view from the first pit I dug. The surface is at Lee’s waist.

Shortly after we started digging, I decided to go for one of the deadmen while Lee continued to reach the battery box(es). The deeper I dug, the more the “digging” became stabbing to break up the hard snow and ice, the pieces of which I would shovel out. It became exhausting. The guy wire never seemed to end, and when it seemed as though I would never reach the deadman, I struck metal. The relief was short-lived, as there was even more ice built up around the deadman, and its length (about 2 feet) was greater than I anticipated. It’s difficult to describe how good it felt to finally break it loose.

Yes!

Yes!

I had gotten two of the guy wires and deadmen out, and Lee was still digging for the battery box(es) and the third guy wire, when we had a conference with everyone to determine whether it was reasonable for us to try to dig out the whole power system. We decided it wasn’t; there was far to much digging to do. Given John and Melissa’s success snowmobiling to the site, it helped make our decision to hold off with the power system raise until next season. We can set up a 3-day camp then and complete the rest of the digging. Before we left, I wanted to make sure we got all of the deadmen out.

The power system, with all three deadmen dug out

The power system, with all three deadmen dug out

Lee pulled out the last deadman from the pit, and the way in which he did it couldn’t have been better. I had chiseled it out from the ice and snow, and it just needed a good hard yank or two to get out. Lee was holding the guy wire and was standing at the top of the pit, yanking away. I was watching as I saw it coming looser and looser. On the last yank, Lee had tugged so hard that he lost his balance and fell backward…..into the first pit I had dug. The riggers were watching and instantly burst out laughing, as at one moment they saw Lee and the next he was out of sight. Fortunately, he wasn’t hurt. We had filled up the hole about halfway with some chunks of snow that we had dug out from other holes. It was a funny way to say so long to Tall Tower!, until next year.

Cheers!

Dave

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Helo to Ferrell and Lorne AWS

The busy-ness (ha!) continues. Our days have been filled with work this week, which is always welcome down here. Things can get boring pretty quickly if there isn’t any work to do. I’m squeezing in this blog post so I can keep up with the work that we’ve been doing. If I wait too much longer, this information will be too old to post!

This past Monday, 27 January (Lee and I both agree that that feels WAY longer than 2 days ago), we flew by helo to Ferrell (install freewave transmission) and Lorne AWS (station check up). It was a relatively easy day for fieldwork.

We arrived at Ferrell, and the first thing we needed to do was install the freewave antenna.

Lee getting the freewave antenna ready to be installed. That small tower section on the far left is the old Ferrell AWS.

Lee getting the freewave antenna ready to be installed. That small tower section on the far left is the old Ferrell AWS.

When installing the antenna, we needed to make sure it was angled slightly away from the surface so it could hit White Island AWS. Ferrell AWS was beginning to lean, so mounting the antenna with a normal bracket caused the antenna to point into the ground. We brought a bracket in which we could angle the antenna correctly and got it installed.

Ferrell AWS upon completion. Notice the angled black antenna on the right of the station.

Ferrell AWS upon completion. Notice the angled black antenna on the right of the station.

We verified the freewave transmissions were working and hopped on the helo to go check on Lorne AWS (the helo stayed on site with us as we did our work).

We were unsure whether Lorne AWS needed to be raised or not. To our delight, the station height looked good, so all we really needed to do was remeasure the instrument heights.

Lorne AWS, with Lee and our helo pilot Ryan on the left.

Lorne AWS, with Lee and our helo pilot Ryan on the left.

Once that work was done, we could head back to McMurdo. Piece of cake! One advantage to doing helo trips is they’re (inherently) quicker than Otter trips, so it doesn’t take an entire day to do a couple stations’ work. On Monday, we left McMurdo at around 9:15 am and returned around 3 pm. When we did return, we spotted some welcome visitors on some ice offshore!

Some Adelie penguins hanging out on broken sea ice.

Some Adelie penguins hanging out on broken sea ice.

A digression: Good news arrived to McMurdo the night prior (Sunday 26 January) in the form of John, Melissa and Suz (if you’re keeping track at home, Ben the Kiwi had already made it back to town a few days sooner than the rest)! They returned from their 12-day camping trip out at Tall Tower! AWS, and they were all in good spirits. Based on their experience, it seems like snowmobiling out to Tall Tower!, rather than taking the Twin Otter, is the way to go; it’s much more reliable, as we would be able to depart practically whenever we wanted because we wouldn’t be hindered nearly as much by the weather. As far as John and Melissa’s science work is concerned, they were able to get it all completed successfully. An overall great trip for them!

Back to the original subject: With Monday being a success, our work with helo travel was completed. It’s all Otters for us from here on out (except a snowmobile trip or two). Lee and I flew by Otter yesterday and today, and I’ll reserve those fun stories for the next couple blogs.

Cheers!

Dave

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Twin Otter flights to Lettau AWS and Tom AWS

It’s been another busy week as we visited more AWS. On Wednesday 22 January and Thursday 23 January Lee and I flew by Twin Otter fixed wing aicraft to Lettau AWS, on Wednesday, and Tom AWS, on Thursday. Wednesday was my first flight on a Twin Otter, so I was eager to get flying. But, of course, it’s not as simple as hopping on the plane and leaving.

There is more time and preparation that goes into flying by Otter than by helo. All the cargo, aside from the literal passengers and some small bags, needs to be entered into the cargo system. Then, as opposed to departing right from McMurdo as you do with helo, the Otter departs from Pegasus airfield. The cargo needs to be ready out there when we want to fly, so we need to enter it into the system at least 2 days before we fly. We find out if we’re on the schedule to fly the night before flight date. Around 7 am the following morning we get a call from fixed wing ops whether we are a go or we have been canceled. If we’re a go, we need to catch the shuttle out to Pegasus, which leaves McMurdo at 8 am. The time between the call and the shuttle can get hectic. That shuttle ride is about an hour, and it takes about an hour to prepare the Otter for flying (loading cargo, fueling up, etc). And finally, inherent in Otter flights is that the travel time to AWS is almost always longer than helo because we only use the Otter for AWS that are too far away for the helo to reach. I’ve now discovered that all these factors add up to very long work days when flying by Otter.

Lee and the Otter, preparing to depart Pegasus

Lee and the Otter, preparing to depart Pegasus

The flight to Lettau took 2 and a half hours. It’s a great time for reading, taking a nap, or enjoying the sights.

Length aside, it’s always great to get to AWS, especially when we get one working again like we did at Lettau. Our goal was just what we accomplished: install the enclosure and get the station transmitting again via Argos. All the instrumentation was already on the tower. The only additional thing we needed to do was raise the lower temperature sensor about a foot. There isn’t usually much accumulation there, so that usually makes servicing easier.

Arrival at Lettau AWS

Arrival at Lettau AWS

Me, securing the enclosure

Me, securing the enclosure

Lettau AWS upon completion

Lettau AWS upon completion

On Thursday, we flew to Tom AWS. We had ambitious goals for this day; we wanted to remove Tom and reinstall it at a location nearby, but far enough away to measure data unique to the original location of Tom. This flight took just over 3 hours, and considering how long it usually takes to remove and install an AWS, our plans had us pushing right up against the Otter pilots’ duty days (the number of hours they can work in a day; I think it’s around 14 hours).

We arrived to Tom AWS at 1 pm and got to work right away. This was a full removal, so we needed to dig out the tower section, batteries, and the dead men attached to the guy wires.

Arrival at Tom AWS

Arrival at Tom AWS

There was more accumulation and many more layers of ice than we anticipated, so the removal took too long. It was the only thing we could do that day. We also had to cut our time there short because we needed to stop at a fuel cache along the way back to McMurdo to refuel. All four of us, myself, Lee and the two pilots, ended up digging the station out. Each of the holes (4 total) ended up being about 5 feet deep. One consolation to the rapid and tiring work was that we successfully removed it all.

Proof of the successful removal

Proof of the successful removal

It was time to head back to McMurdo, first stopping at CTAM (the Transantarctic Mountains Field Camp) to refuel. The scenery was stunning. We flew along and over the mountains for the hour-long flight to CTAM.

The Transantarctic Mountains

The Transantarctic Mountains

IMG_2854 - amrcblog

IMG_2860 - amrcblog

IMG_2875 - amrcblog

When we got back to McMurdo around 9:30 pm, we ate a late dinner (24-hour pizza, yes!) and then got some shut-eye.

Cheers!

Dave

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Helo to Linda AWS

Lee and I knocked off another station on our to-do list when we flew by helo to Linda AWS yesterday, 20 January (I suppose you could consider this part of the helo bonanza). We needed to dig out and remove the old instrumentation, raise the station, and install new instrumentation. We also wanted to set up freewave transmission for it, but we were prepared to use Argos transmission if the freewave failed and we couldn’t connect to White Island. The weather was great, with clear skies at McMurdo. At Linda we were on the edge of some high clouds, and there was only a slight breeze… Excellent working conditions.

The helo leaving us at Linda AWS

The helo leaving us at Linda AWS

Once they left, we got right to work. We set up our GPS instrument to get the coordinates for the site, then started digging. We needed to remove a couple of buried instruments, a lower temperature sensor and a junction box. This proved slightly more difficult than we first anticipated due to a layer of ice that had formed around the instruments. Once we recovered those, we could free up the cables for the removal of the rest of the instrumentation. The next order of business was to install the 7-foot tower section. Once that was installed, we put up the new instrumentation.

Our working area, with Lee on the tower installing instruments

Our working area, with Lee on the tower installing instruments

The high clouds started slowly creeping overhead, so we were glad that once we got all of the instrumentation secured, we were able to connect right away to freewave. It was just about as painless an attempt as one could imagine!

The completed Linda AWS

The completed Linda AWS

The new instrumentation we installed are (from top to bottom) an anemometer, temperature sensor, solar panel, freewave antenna, relative humidity sensor, acoustic depth gauge (measures snow height), pyranometer (radiation sensor), an infrared sensor to get the snow surface temperature, the enclosure including a pressure sensor, and last but not least a battery box to power the station.

I’ll close this post with more penguin photos! These were taken Sunday night, 19 January. Some folks from POLENET, the science group we share an office with in Crary, said they saw 4 penguins on the ice near McMurdo. I got my camera and went down to be treated to many more than 4! I watched them for about an hour, and at one point one hopped on shore about 25 feet away from me.

Adelie penguins. We saw them swim along the shore too!

Adelie penguins. We saw them swim along the shore too!

I had just sat down to view some penguins in the distance when this guy hopped up on shore

I had just sat down to view some penguins in the distance when this guy hopped up on shore

Adelies, with Mt Discovery as a backdrop

Adelies, with Mt Discovery as a backdrop

Cheers!

Dave

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Helo trip to Pegasus! (And Ferrell AWS)

And so continues the helo bonanza. On Thursday 16 January we were planning to helo out to Ferrell AWS to switch the data transmission from Argos to freewave. Of course, all of these flights depend on good weather, and Tuesday and Wednesday were beautiful days for flying. On Thursday, however, there were some low clouds apparent on the satellite imagery to the east of White Island, which is where Ferrell AWS is located. This didn’t bode well for a helo landing, as the surface becomes nearly impossible to define when there are low clouds over ice. Lee and I arrived at the helo pad, talked with the helo techs and decided that we would take the trip out there and determine whether it was safe to land upon arrival.

There were only high clouds in the McMurdo area, but a few minutes after we departed we started seeing the low clouds. They became thicker and more widespread as we approached Ferrell.

Low clouds, as seen from the helo. The surface became completely obstructed from view the closer we got to Ferrell. The clouds did have a cool, hill-like appearance though.

Low clouds, as seen from the helo. The surface became completely obstructed from view the closer we got to Ferrell. The clouds did have a cool, hill-like appearance though.

A few miles from Ferrell, we decided that it was unsafe to land so we turned around and headed for McMurdo. Over the intercom, Lee said to me that now we could go to Pegasus AWS and finish up work there, as we would have time to take a shuttle from McMurdo. The pilot and helo tech heard this and said, “Why don’t we just drop you off at Pegasus?” We said, “Why not!!”

Lee and I arrived to Pegasus in style. Most often, to get to Pegasus from McMurdo you would take a shuttle, and the drive can take an hour or more. It’s funny to think that Lee and I took a helo from McMurdo, to Ferrell, then to Pegasus in about the same amount of time as a shuttle ride to Pegasus.

It was very generous of the helo guys to drop us off. It saved us a lot of time and gave us a chance to eat our flight lunches in the Pegasus galley. Once well fed and rested, we headed out to our AWS to finalize the freewave transmissions there.

Pegasus AWS, with White Island (where we are directing our transmissions) in the background

Pegasus AWS, with White Island (where we are directing our transmissions) in the background

As we were waiting to verify the transmissions were successful, I noticed a very cool cloud feature on the horizon near White Island. It’s called Kelvin-Helmholtz instability, and it occurs when there is a velocity and density difference across two layers. This can result in a wave-like cloud structure as it did for us that day.

Kelvin-Helmholtz wave clouds

Kelvin-Helmholtz wave clouds

Once we were done admiring that spectacle, we verified that the freewave transmissions worked at Pegasus. After several trips to the station, we finally diagnosed the problem and fixed it successfully. We then headed back to the airfield to catch a shuttle to McMurdo. On our short drive to the airfield, we were treated to the always-welcome sight of four penguins, seemingly on a journey somewhere.

Four Adelie penguins at the airfield

Four Adelie penguins at the airfield

On Friday 17 January, we (continuing the helo bonanza) flew out to Ferrell AWS. This time, the weather cooperated. The skies were clear between McMurdo and Ferrell and beyond. The only very minor issue was the wind; it wasn’t too windy but it was constant as we worked. At Ferrell, we wanted to switch the data transmission to freewave. We also noticed that the lower temperature sensor was buried, so while Lee was fixing up the freewave antenna, I dug out the sensor to be raised.

Ferrell's lower temperature sensor

Ferrell’s lower temperature sensor

Unfortunately, after trying to adjust the direction of the antenna and attempting to connect via the laptop, we could not establish a connection between Ferrell and White Island AWS. We will have to visit the station again; fortunately, the helo schedule is pretty open, so we are actually on the schedule to do this visit sometime next week. For now, Ferrell is still transmitting via Argos.

Ferrell AWS after we did our work

Ferrell AWS after we did our work

Today, Saturday 18 January, we were hoping to yet again continue the helo bonanza to Linda AWS, but we got canceled due to weather. It is far too windy (~60 mph winds at Black Island, which is on the way to Linda). Hopefully we can get there next week.

More updates as they come.

Cheers

Dave

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Cape Bird

On Wednesday 15 January, Lee and I continued our helo bonanza by flying to Cape Bird AWS. Just like Tuesday, the purpose of this trip was to check on the AWS and make sure things looked ok. Before flying to Cape Bird, there are a few important considerations the helo operations personnel have to consider.

Cape Bird is at the northern end of Ross Island, while McMurdo is at the southern end. The helo cannot fly over open water, so it either has to fly over land or ice. This is important to keep in mind, especially this time of year, because at Cape Bird the sea ice breaks up and melts, leaving open water in its wake. There are also a few areas on the island along the route that are no-fly zones, due to penguin rookeries. Ross Island becomes more narrow, and essentially becomes a peninsula, as you approach Cape Bird. Consequently, there is only a thin flight path. If there is enough cloud cover that makes it difficult to see land, this flight can become hazardous and unsafe to do. There are some cliffs at Cape Bird where the helo needs to land, so good visibility is essential. Luckily for us, the skies were mostly clear so we could fly to Cape Bird with ease. The helo pilot even asked me to take some pictures of the area where the flying becomes precarious as he took waypoints to document the surface features.

View of part of the "precarious area" on our way to Cape Bird. This is looking back toward McMurdo. You can see the elevation is steep along the coast, and there is plenty of open water. Mt Erebus is out of view but to the front left.

View of part of the “precarious area” on our way to Cape Bird. This is looking back toward McMurdo. You can see the elevation is steep along the coast, and there is plenty of open water. Mt Erebus is out of view but to the front left.

A successful landing at Cape Bird. Note the cliffs

A successful landing at Cape Bird. Note the cliffs

A huge bonus about coming to Cape Bird is that there is an Adelie penguin rookery there. So I got to see more penguins! There were some roaming on the beach, and we could see lots in the water swimming and jumping into and out of the water, or standing on icebergs. They looked like they were having fun out there!

Penguins hanging out on a berg

Penguins hanging out on a berg

We said hello to some of the Kiwis (New Zealanders) who are stationed at the Kiwi Base there at Cape Bird, then walked up the somewhat steep hill to check on our AWS. Lee and I were anticipating a quick look-around and our work there would be done, but that was an optimistic expectation. At first glance it looked to be ok, but upon closer inspection we noticed the propeller on the anemometer had come completely off, the temperature sensor was missing its radiation shield, and one wing on a wind turbine for Lars Kalnajs’ ozone detection system had broken off.

Cape Bird AWS upon arrival. Lars' instrumentation is on the right

Cape Bird AWS upon arrival. Lars’ instrumentation is on the right

Right before we departed McMurdo, Lee had the brilliant idea to bring a spare nose cone and propeller for the anemometer, just in case. Turns out we needed it! We got to work on installing that to the anemometer and searched for the missing parts. I stumbled across the broken propeller (it was about 15 feet from the station), but couldn’t find a trace of the radiation shield or broken piece from the wind turbine. We think that high winds picked up some rocks and caused this damage to the station, perhaps taking out all of the broken pieces in one fell swoop, or maybe there were two or three separate instances. There was a fair bit of corrosion on the station due to the sea, but despite these defects we verified that the AWS is still recording and transmitting measurements. The wind speed and direction are back on as well.

Cape Bird AWS after we fixed what we could

Cape Bird AWS after we fixed what we could

We will need to visit this station again to install a new radiation shield for the temperature sensor. Until then, the temperatures it records will be invalid as the sun can shine directly on the sensor, heating it up so the temperature it records is no longer a measurement of the air. The relative humidity sensor has a temperature sensor in it, used to calculate the relative humidity, so that should still be accurate and could be used if needed.

Throughout our visit, I was able to snap some pictures of the penguins and scenery. Here are a few that I took.

An Adelie started walking towards me as I searched for the radiation shield, apparently with complete disregard for where it was going. This skua didn't like how close the Adelie came to its chick (not pictured)

An Adelie started walking towards me as I searched for the radiation shield, apparently with complete disregard for where it was going. This skua didn’t like how close the Adelie came to its chick (not pictured)

The Adelie penguin rookery

The Adelie penguin rookery

The Adelie Penguin Photoshoot

The Adelie Penguin Photoshoot

Adelies seem to enjoy the attention

Adelies seem to enjoy the attention

Cheers!

Dave

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Day of Travels

Tuesday 14 January was a traveling day for our group. John and Melissa (along with Ben Jolly, a grad student from the University of Canterbury Christchurch, New Zealand, and Suz, a mountaineer) departed McMurdo for Tall Tower! AWS by snowmobile in the morning, with the goal of reaching the site about 8 hours later. They will be camping out at Tall Tower! for two weeks using UAVs (Unmanned Aerial Vehicles) to take measurements of the boundary layer, the lowest part of the atmosphere where most of the sensible weather occurs. As such, they had to bring a LOT of cargo with them (4 snowmobiles hauling ~1200 lbs of cargo each). Hopefully they made it there in a reasonable amount of time!

Lee and I did some traveling by helicopter yesterday. We flew to our AWS at White Island, Minna Bluff, and Marble Point. The purpose of this trip was to do station check-ups at each of the AWS, and there was nothing but good news; all of the stations looked fine, with only some very minor kinks.

Flying from AWS to AWS, we saw some awesome scenery. To top it off, I got to ride in the front of the helo, giving me a great vantage point of the sights. I’ll let the pictures (and associated captions) do the rest of the talking for this post.

Sitting in the front, on the way to White Island (pictured)

Sitting in the front, on the way to White Island (pictured)

White Island AWS, Lee, and the helo

White Island AWS, Lee, and the helo

At Minna Bluff. It was majestic flying over the cliffs

At Minna Bluff. It was majestic flying over the cliffs

Minna Bluff AWS

Minna Bluff AWS

Flying from Minna Bluff to Marble Point, we saw an isolated snow shower over Brown Peninsula

Flying from Minna Bluff to Marble Point, we saw an isolated snow shower over Brown Peninsula

The sheets of precipitation

The sheets of precipitation

The distinction between land and blue ice is stark

The distinction between land and blue ice is stark

Marble Point I AWS

Marble Point I AWS

Marble Point II AWS

Marble Point II AWS

On our way back to McMurdo we saw penguins, such about a dozen penguins and half as many whales!

On our way back to McMurdo we saw about a dozen penguins and half as many whales!

Cheers

Dave

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