Tag Archives: Science

Robot Boyz

Above all else Summit Station is a polar scientific research station. We are here for Science!
Much of the research done up here is in the vein of long term monitoring; an instrument is deployed to take measurements for months or years without needing specific personnel here on site aside from the Science Technicians. We have several suites of instruments from many different groups. Some measure black carbon in the atmosphere, others measure cloud height, type, and precipitation, there’s a lot of atmospheric monitoring in general, a seismometer, and several solar radiation sensors.
The other type of research involves bringing the researchers themselves up here – either to install instruments, drill cores, collect samples, or test new technologies. The flight periods are the busiest times on station with many groups coming up for just a few days or a week, but some groups stay between flight periods. This past month, between flight periods 4 and 5, we are supporting two PhD students from Dartmouth who are here working with a robot. The Cool Robot.
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Their main objectives are to field test a new version of this robot, to prove that robotic surveys are feasible and practical. If they can be proven reliable robots could be used to track snow topography and elevation, ablation, accumulation, and all sorts of other parameters with significantly higher precision than the satellites we now rely on.
This particular robot is designed to follow a designated path while towing a ground penetrating radar (GPR) unit to measure compaction rates and densities. It is also carrying an infrared camera, which the researchers hope to measure exact surface area of the snow that can then be used to determine gas-air transfer rates. Finally, it includes a radiometer to measure the albedo of the surface – and thus how much solar energy it’s reflecting vs absorbing.

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Solar panel patterns

Some of the issues they’ve had to deal with is the robot filling with snow in high winds, the tires sinking in soft snow, losing traction on hard snow, hitting steep drifts and getting pushed off course…it’s a sometimes slow process, but overall I believe they’ve had great success and have their issues to delve into this winter when they return home.
It’s a boxy little thing, covered in solar panels. It doesn’t move very fast, maybe a 5mph at most, and we’ve grown used to seeing it putter around camp from one site to another. Check out their webpage and field blog: http://sites.dartmouth.edu/polarregionsrobotics/field-blogs/greenland-2017

Science

The “Robot Boyz” discuss annual layers in a back lit snow pit dug near station

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Plastic Balloons

The ozone layer is a vital part of our atmosphere, filtering out harmful solar radiation. One of the projects we support here at Summit is measuring the atmospheric ozone over the Greenland ice cap. For most of the year the techs use simple rubber balloons that reach heights of 20-30km. During very cold periods in the winter the rubber becomes brittle resulting in a burst at lower altitudes. These times however, are often when the ozone is the thinnest and most interesting. So the techs use much larger plastic balloons which can reach heights of 30-40km even in the coldest temperatures. These plastic balloons are not elastic like the rubber ones so they appear quite empty at launch. As the balloon rises through the atmosphere the helium expands filling it out completely.

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A normal rubber balloon

Plastic balloon launches generally only happen once or twice a year so it’s kind of exciting. They are huge and fragile and require all hands. First we laid out canvas tarps to protect the balloon from the potentially sharp ice and snow on the ground. Then we placed the balloon on the tarps ensuring it was free of kinks and tight folds. A carefully calculated weight was hung from the balloon to ensure we added the proper amount of helium. Too much helium and it would rise too fast for the calibrated instruments to measure properly. Too little and it might not rise fast enough or get high enough. Helium bottles were moved closer to the door and a long hose run out to the filling tube on the balloon. Filling took quite a while.

Once the balloon was filled with a sufficient amount of helium we connected the instrument box and carefully walked the whole thing to an open area away from the building and major drifts. One person held the inflated part of the balloon, careful not to let it pull too strongly or touch anything in the wind, two more held the middle section of the balloon off the ground, and a fourth held the instrument box. At a count of three everyone let go in sequence allowing the balloon to lift smoothly away from our arms and rise into the sky…

Back in the Green House we listened to the data being received; a Morse code like series of beeps and boops. When the signal grew weak or distorted one of the techs climbed onto the roof to adjust the antenna. The latest ozone data from Summit can be found here: www.esrl.noaa.gov/gmd/graph.php

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Ozone levels above the Arctic

img_1717Last week we hit a low of -73F according to the Green House thermometers. This week however,  has been dark and stormy with temps around -30F and winds around 30kn. Lots of shoveling to be done!

{Also, some of my halo photos from this fall have their own page at Atmospheric Optics check it out!}

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The horizon is growing brighter every day!

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A full moon shines over the Big House

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Nacreous Clouds!

The sun is on its way back and while we still have 3 weeks until the first sunrise each day is a little brighter than the last. New Year’s Eve dawned bright and clear with crisp stars and a few very special clouds on the horizon. At first they were startling neon pink, orange, and red. The first real sign of the sun in weeks and a beautiful contrast to the greens and blues of the night sky and aurora. As the day progressed the clouds grew in size, becoming clearly iridescent. With no insulating clouds overhead it was a chilly -60F ambient. The cold temperature, otherwise clear sky, low sun, and wavy iridescent features all pointed towards these clouds being Polar Stratospheric Clouds (aka PSCs or Nacreous Clouds).

These rare clouds are both terrible and beautiful. Forming in the stratosphere at 49,000-82,000ft and at temperatures below -100F they are composed of water, nitric acid and/or sulfuric acid. While beautiful, they are implicated in the depletion of stratospheric ozone – an important protective layer against harmful UV rays. According to TheOzoneHole.com:
PSCs were long regarded as curiosities and of no real consequence. However, Type I clouds are now known as sites of harmful destruction of stratospheric ozone over the Antarctic and Arctic. Their surfaces act as catalysts which convert more benign forms of man-made chlorine into active free radicals (for example ClO, chlorine monoxide). During the return of Spring sunlight these radicals destroy many ozone molecules in a series of chain reactions. Cloud formation is doubly harmful because it also removes gaseous nitric acid from the stratosphere which would otherwise combine with ClO to form less reactive forms of chlorine.”

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Bright neon clouds

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Polar Stratospheric Clouds – note their brightness, iridescence, and feathery/wavy structure

Measuring the ozone layer above us and the seasonal Arctic ozone hole is one of the many projects we support here at Summit. Every week the science techs launch a large balloon with a carefully calibrated instrument to measure ozone concentrations, as well as normal meteorological data (wind speed and direction, pressure, temperature, and humidity). The data is sent back via radio signal to the computer here at Summit.

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Lidar

It was lightly snowing last night, ice crystals falling from high, thin clouds as I walked from the Big House to the Green House. Looking towards the MSF there was just enough ice in the air to illuminate the ICECAPS LiDAR – a laser measuring cloud matter, phase, and crystal orientation. ICECAPS is a relatively large, long-term project researching cloud characteristics and their impact on climate. This knowledge is crucial in developing climate models as well as understanding our changing climate. More information can be found here: www.esrl.noaa.gov/arctic/observatories/summit.

Most of the time the laser is invisible, however with just the right conditions enough light can be reflected back to show the brilliant green beam. If you look carefully you can also see the vertical laser, however this is weaker and thus less visible. Beautiful science!

*If you are familiar with LiDARs you may have seen this spelled LIDAR, lidar, LiDAR, or LADAR – according to NOAA’s Digital Coast Blog all spellings are correct though LiDAR is gaining in popularity. 

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The ICECAPS LiDAR here at Summit

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The LiDAR at NOAA’s ARO facility at the South Pole Station

 

An example of the LiDAR data:

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Around Mac Town

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Ross Island dominated by Mt. Erebus in the center as seen from out on the ice shelf. McMurdo and Scott Base are located on the dark area to the left.

The weather in Antarctica is notoriously capricious, especially in the stormy West Antarctic, and its storms are legendary. Teams heading out to the “Deep Field” are brought into McMurdo several weeks in advance to complete training and preparations for the field, but also to give a buffer for deployment to field sites. Weather delays of a week, or two, or three are not uncommon especially when combined with ageing aircraft and shifting priorities with many groups needing to utilize flights. Once field preparations are complete we volunteer with other departments and projects and take advantage of the hikes and activities offered around the main USAP hub of operations. It can be frustrating at times to have clearly defined projects and goals and not be able to start. On the other hand most deep field camps are on the bright flat white so the majestic mountain views, hiking trails, and wildlife are savored while amenities like hot showers and warm dark rooms are appreciated. I wrote a post about McMurdo back in 2012 – not too much has changed : ) Check it out here: antarcticarctic.wordpress.com/mcmurdo-station-aka-mac-town and another here: antarcticarctic.wordpress.com/2014/11/10

CRREL: This year I’ve spent a fair bit of time assisting some friends with the Cold Regions Research and Engineer Laboratory (CRREL) as they conduct ground penetrating radar (GPR) and GPS surveys of the McMurdo area. One project is looking at the structure of the McMurdo ice shelf. With the airfields and runways built out on the flat ice it is an integral part of USAP logistics and would pose a huge problem should a large piece calve away unexpectedly. To do the survey we towed 200MHz and 400MHz GPR devices behind snowmobiles along predetermined transects using a precision Trimble GPS unit to record location and elevation. Ice cores were manually collected to determining the depth of the brine layer – essentially the ice depth at specific points. The cores ranged from 5-16 meters deep!
The sea ice, which may break up during the summer, is roughly 1-7m thick, while the ice shelf which remains frozen year-round reached depths of greater than 40m!

Another project was examining the geology and bedrock structure of the McMurdo area in town. While there are still significant patches of ice and snow it’s starting to melt out and most of the roads are clear by now. We made an amusing sight: one person in the lead with a rope around their waist dragging a bright pink plastic sled loaded with a big orange box along the gritty uneven rock roads and hillsides…the other person walking next to the sled wearing a yellow backpack with a big antenna sticking out the top.

SPOT: The South Pole Traverse is heading out around this time of year too so there is a lot to do to help them get cleaned up and on the ‘road’ to Pole. I spent several days helping the SPOT teams reorganizing drums and securing cargo to their sleds. While their set-up is much larger and more complicated than ours will be, the theory is all the same and it was good to re-familiarize myself with the Cat Challengers, though the ones we will be using at WAIS are far older and a bit smaller. See my previous post for more information on SPOT: Antarcticarctic.wordpress.com/spot

Dive Tending: One morning I got to assist the Divers. On that particular day they were recording water column visibility along a steep drop-off not far from the station. We met in town and loaded up a Pisten Bully with all their gear and supplies. Out on the ice we stopped at one of the “Fish Huts.” Small brightly colored buildings, the heated huts sit over maintained holes in the ice at designated dive points. Bundled up in long underwear, a full insulated down suit, and a sturdy dry-suit the two divers were uncomfortably warm while we got everything ready. Gear was brought inside the hut and a line was tied off to the hut wall and then lowered into the water with strobes, flags, and an emergency air tank. In the dim light under the ice and with very limited places to surface it is imperative not to lose the dive hole! Then sitting at the edge of the hole, with practiced efficiency, they pulled on their hoods and masks, strapped on their weights and flippers, locked on their thick lobster-claw mittens, and hoisted on their air tanks and regulators…and then they slipped into the hole!

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With a burst of bubbles they sank down the 3-4ft hole through the sea ice and disappeared into the dark water. Once they were gone I lowered the ladder and closed the shutters of the hut. The sunlight filtering through made the ice glow an electric blue around the black water. The dive lasted about 20 or 30 minutes as I watched from above noting feathers, or platelets, of ice growing on the surface of the ~28F water and keeping an eye out for the divers as they swam under the hole.

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The second diver about to enter the water

Before I knew it there was a mass of bubbles and one of the divers appeared in the hole. I assisted with hauling out their heavy air tanks so they could climb the ladder and warm up next to the stove. Then it was back to town in time for lunch!

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Pressure Ridge: An interesting feature in the McMurdo area is the pressure ridge. An area of ice that’s been forced together by ice flow and tidal movement it forms each year right in front of New Zealand’s Scott Base. With unrelenting pressure the ice is driven into the air cracking and breaking to form stunning features – the snow bright white and the ice glowing a deep blue. With so much relative ice movement thin spot and air holes form making it very popular with the Weddell seals in the area.

A friend’s website with some amazing photography of pressure ridges and more can be found here: www.benadkisonphotography.com/antarctica

Ob Tube: The Observation Tube (aka Ob Tube) offers a unique glimpse under the sea ice just in front of McMurdo. A tube, anchored to the ice surface, houses a ladder down 10ft or so to the base where there is a small round area with windows. Not for the claustrophobic, it is a tight fit and is quite dark. Some light filters through the ice to illuminate sea stars on the ocean floor while tiny fish, jelly fish, and pteropod “Sea Angels” float past the thick ice rimmed windows. Perhaps most notable is the texture of the sea ice base. While the top of the sea ice is a varied terrain of snow, blue ice scoured clear, or area of melt later in the summer, the base is comprised of delicate sheets and leaves of ice called platelet ice. The seawater is below freezing here at ~28-29F on average and as the fresh water freezes a salty shimmering brine solution is formed just below the ice level.
Later in the summer the ice will thin and possibly break up here so the Ob tube is a temporary feature only deployed for a few weeks in November.

Check out this post from a fellow polie about the Ob Tube here: http://davidpablocohn.com/ob-tube

Arrival Heights: Arrival Heights is an area just Northeast of McMurdo Station proper, not far from the Castle Rock hiking loop trail. It is an area reserved for clean air sampling and radio and light sensitive experiments – a bit like Summit’s Clean Air Sector and South Pole Dark Sector combined. Several special camera suites study auroras so in the winter the use of lights is kept to a strict minimum. Other experiments are looking at the ionosphere and magnetosphere (space weather) utilizing huge antenna arrays which are highly sensitive to radio transmissions.

As an Antarctic Specially Protected Area (ASPA) it is off limits to the public at large, however occasional guests are permitted as long as they are accompanied by official personnel and traffic, either by foot or vehicle, is limited to designated routes only.
Exposed to some brutal winds it also offers one of the most beautiful views with the Royal Society Mountain Range clearly visible to the West and unhindered views North towards Cape Evans and the sea ice edge.

 

Cape Evans:
About 20km North of McMurdo Station on Ross Island is Cape Evans. Named for Robert Falcon Scott’s second-in-command Lieutenant Edward Evans it was the staging point for the British Terra Nova Expedition of 1910-1913 .
The expedition’s hut, now dubbed Scott’s Hut, was prefabricated in England and reconstructed on Cape Evans in 1911. It was built to house the 25 men of the expedition during the following winter while they prepared for the journey inland. With lessons learned from Scott’s previous, and frigid, Discovery Hut (located on Hut Point, just a short walk from McMurdo Station and used by Scott during the 1901-04 Discovery Expedition) the 1911 Cape Evans hut contains two stoves, better insulation, and is surrounded on some sides by a covered stable and storage area. Some of the men reported that it was “warm to the point of being uncomfortable.”
In the austral spring of 1911 Scott and several of his men set out to be the first men to reach the South Pole. For more information on that check out this fantastic 2011 article Race to the South Pole by the National Geographic. They arrived on January 17, 1912 to find a tent and a note from Roald Amundsen who had reached the South Pole first on December 14, 1911. Their dreams dashed, they headed towards the coast, however suffering from malnutrition and cold injuries there were no survivors.

This is of particular historic significance as it was this brutal expedition that arrived at the South Pole (just behind Norwegian Roald Amundsen) and from which Scott never returned. Several men remained at Scott’s Hut for the winter of 1912 to search for Scott’s party, however in 1913 they left Antarctica as well, leaving Scott Hut stocked with supplies.

The Hut was used again in 1915-17 by 10 men from Ernest Shackleton’s Ross Sea party after their ship, the Aurora, with the rest of the crew, broke adrift and was taken North in the ice in May 1915. The Ross Sea party was the counterpart to Shackleton’s 1914-17 Imperial Trans-Antarctic Expedition expedition, the ill-fated attempt to cross the continent. They were responsible for laying supply depots for Shackleton’s return from the Pole, however Shackleton trapped in the ice aboard the Endurance, failed to ever reach the continent itself and so the entire effort was for naught.

Due to sub-freezing temperatures, low humidity, and conservation efforts by the US and New Zealand and the Antarctic Heritage Trust both Scott’s Hut and Discovery Hut have remained much as they were left in the early 20th century; Beds are made with shoes tucked beneath, a desiccated and partially dissected penguin lies on a table, glass vials of medicine and solutions line shelves while the kitchen is well stocked with tins and cartons of various food stuffs. A massive pile of seal meat is stacked out in the covered storage area, fairly well preserved for being over a hundred years old, though smelling a bit rancid…The entire site is full of amazing artifacts from the expedition such as snowshoes for their ponies, and cartoons tacked to the wall.

Check out Amusing Planet’s page on Scott’s Hut for more information on the hut’s artifacts and the expedition in general: www.amusingplanet.com/captain-robert-scotts-hut-in-antarctica.html

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Summit Science!

As in Antarctica, our purpose in Greenland is science – primarily climate research. Summit Station was first established in 1989 to support the Greenland Ice Sheet Project Two (GISP2) ice core and has since become a leading arctic station supporting a wide variety of seasonal and long term projects.

Summit was chosen for its location at the summit of the Greenland ice sheet. Some facts: There are two ice sheets on earth, one in Antarctica and one in Greenland, and as they are near the poles we call them ice caps. According to the National Snow and Ice Data Center (NSIDC – based in Denver) an ice sheet is defined as a “mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles).”  Glaciated areas less than 20,000sq mi are called ice fields – such as the Patagonia ice field, or the Juneau ice field.
Ice sheets and ice fields are incredibly important to climate research as they are not only highly sensitive to global temperature changes but provide a physical archive of the atmosphere going back as long as the ice has been there. The water molecules of the snow/ice itself contain isotopes that correlate to average global temperatures and between these molecules, bound by the ice, are tiny trapped air bubbles – discrete samples of atmospheric gases. This is one way scientists can measure carbon dioxide (CO2) levels over past millennia. The Vostok ice core for example, provided data on the climate going back over 400,000 years. The European Project for Ice Coring in Antarctica (EPICA) ice core goes back 800,000 years. CO2 levels are of particular interest to climate scientists as there is a direct correlation between global temperature and CO2 in the atmosphere. Over the past 400,000 years CO2 levels in our atmosphere have fluctuated between 180-280ppm. Since the Industrial Revolution and large scale burning of fossil fuels those levels have continued to rise. Right now we are close to 400 ppm. (check out http://www.esrl.noaa.gov/gmd/ccgg/trends/ for recent levels) The US Environmental Protection Agency has a great website with information on greenhouse gasses and carbon dioxide, trends in the US, and ways to reduce emissions: http://www.epa.gov/climatechange/ghgemissions/gases/co2.html.

The GISP2 borehole in 2011

The GISP2 borehole in 2011.

The GRIP borehole 28km from Summit Station

The 1989-1992 European Greenland Ice Core Project (GRIP) borehole 28km from Summit Station

GRIP Ice cores at the University of Copenhagen in Denmark

GRIP Ice cores at the University of Copenhagen in Denmark

Annual layers are visible in the cut GRIP cores (U. of Copenhagen)

Annual layers are visible in the cut GRIP cores (U. of Copenhagen)

Greenland Ice core sites

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A graph showing CO2 levels from an ice core (Vostok, Antarctica). Our current atmospheric CO2 levels are off this chart.

While the GISP2 ice core was completed over 20 years ago, Summit continues to provide valuable data. As one of NOAA’s Earth Systems Research Laboratories the Greenland Environmental Observatory (GEOSummit) provides long term monitoring of the Arctic environment and atmosphere.  Much of climate research relies on these trends and long term variations to distinguish climate change from variable weather patterns. TAWO (Temporary Atmospheric Weather Observatory) houses a suite of instruments collecting continuous measurements of a number of greenhouse gasses including carbon dioxide, tropospheric ozone, and black carbon among others. Summit’s science techs launch ozone sondes weekly to measure upper atmosphere ozone and collect air samples twice monthly to be processed for trace gases. Once a month the science techs complete a GPS survey (IceSAT) for CryoSat – providing calibration data for a European Space Agency satellite measuring ice thickness around the globe.

Some other long term projects here at Summit include: ICECAPS (Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit) which is studying the atmosphere, clouds, and precipitation. Today a third station science tech position has been added to focus primarily on the ICECAPS instruments. BSI (Biospherical Instruments) is monitoring ultraviolet radiation. GEOFON has a seismometer buried away from camp as part of a global network. A magnetometer has also recently been installed to measure geomagnetic variations in central Greenland.
This season a new intermediate ice core drill was tested near Summit. The proposed project will drill a 1,500m ice core at the South Pole Station in the 2014-15 and 2015-16 seasons. More information on this project can be found here and on the official SPICE Core site.
The complete list of currently funded projects is publicly available on the Arctic Field Projects site.

Some other interesting links:
http://www.esrl.noaa.gov/gmd/obop/sum/
http://nsidc.org/cryosphere/quickfacts/icesheets.html
http://en.wikipedia.org/wiki/Ice_core
http://www.gisp2.sr.unh.edu/

During the summer of 2011 I was one of two station Science Technicians at Summit.  We monitored and maintained the long term research equipment on station, trouble shooting and repairing as needed. We also assisted with launching weather balloons and ozone sondes and collecting various samples for projects. A typical day included doing rounds to clear meteorological equipment of snow/ice/frost/rime, cleaning lenses collecting data on solar radiation with ethanol, backing up data or sending it via email to researchers at their home institutions, collecting air and snow samples, measuring accumulation rates, launching weather balloons, conducting GPS surveys, and assisting around the station as needed. Here are a few pictures of Summit science techs in action…

Launching a weather balloon in April 2011

Launching a weather balloon in April 2011

Measuring accumulation rates at Summit

One of the 2010 techs measuring accumulation rates at Summit

Radiometers measuring solar radiation and albedo

Radiometers measuring solar radiation and albedo

Bundled up for IceSAT

Bundled up for IceSAT – GPS equipment is in the red “Poly Pod” behind me, the survey takes several hours and is done once a month.

Leveling the seismometer

Leveling the seismometer

Cleaning rime off a tower

Conducting maintenance on the 50m “Swiss Tower”

Cleaning rime off the TAWO tower

Cleaning rime off the TAWO tower instruments

Air sampling flasks!

Crates of  air sampling flasks!

Inflating a balloon

Inflating a balloon in the S.O.B.

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Launching an ozone sonde to collect data on the upper atmosphere ozone layer

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SCIENCE! Part III

MAPO

http://www.astro.caltech.edu/~lgg/keck/keck_front

MAPO, or the Martin A. Pomerantz Observatory, is the first building one encounters upon crossing the skiway. The blue box-like building housing the telescopes Viper (now complete and waiting demolition) and SPUD, used to sit high above the snow surface to avoid drifting issues, but the stilts are now long buried.

SPUD is looking at a similar radiation spectrum as the South Pole 10m telescope (about 2mm wavelength) but at a much larger scale with far less resolution. The project is described in the Science Planning Summary USAP-2011-2012 as:
Small Polimeter Upgrade for DASI (SPUD) is the next generation instrument in the ongoing Background Imaging of Cosmic Extragalactic Polarization (BICEPT/BICEP2) program of experiments. It will place multiple receivers similar to BICEP2 on the telescope mount originally built for the Degree Angular Scale Interferometer (DASI) experiment. SPUD will increase sensitivity over BICEP2 by increasing the number of detectors and in future seasons by also expanding to other frequencies to mitigate possible foreground contamination. The scientific objective is the same as BICEP2 – to attempt to measure B-mode polarization caused by gravity waves spawned in the first tiny fraction of a second after the big bang by the process of “inflation.” Inflation is the favored cosmo-genic model and finding direct “smoking-gun” evidence for it is one of the highest priorities in cosmology today. SPUD will increase sensitivity over BICEP2 by increasing the number of detectors, and, in future seasons, by also expanding to other frequencies to mitigate possible foreground contamination.

The South Pole Telescope as seen through the SPUD telescope

As with the South Pole Telescope this is not an optical telescope. The image to the right is of the South Pole Telescope as seen through SPUD.

The telescope is extremely simple as far as telescopes go; inside each receiver two lenses focus the radiation on the primary sensor. Opaque Teflon and nylon disks, looking a bit like the plastic from a milk jug, help filter out unwanted wavelengths. The sensor is comprised of four silicon chips with extremely thin metal resistors imprinted upon the surface. Very slight changes in temperature from the incoming radiation induce resistance variations, producing a temperature map of the sky, of the Cosmic Microwave Background. Five receivers will be mounted inside the ground shield and can rotate 360 degrees as well as scan vertically. From the station the Ground Shield looks like a giant plywood flower or bowl, but inside it’s lined with mirror-like metal. The purpose is to limit radiation bouncing off the buildings and snow surrounding MAPO.

The SPUD telescope attached to the side of MAPO as seen from ground level

The commemoration plaque by the entrance to MAPO

The view from inside the receiver housing, looking down the ladder to MAPO

The walls inside the receiver housing

One of the new receivers before being mounted inside the housing

The silicone film inside the receiver itself

The door into the shield - the part of the telescope visible to the rest of the station

The receiver housing as seen from the outside - note the station seen just above the edge of the ground shield

The mirror lined ground shield reflecting the mottled cloudy sky

The Station as seen from MAPO

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SCIENCE! Part II

10-Meter South Pole Telescope
http://pole.uchicago.edu/

The South Pole Telescope looking at the ski directly above – the metal scaffolding is being added this year in an attempt to reduce “noise” from reflections off the snow surface.

The South Pole Telescope (often referred to as simply 10-meter or “SPT”) is an iconic feature here at Pole. Constructed during the Austral summer of 2006-2007, the impressive two dimensional rotating 10-meter dish located just across the skiway from the station is hard to miss.

In the Science Planning Summary USAP-2011-2012 the SPT project is described as:

Looking at the intensity and polarization anisotropy of the CMB. By surveying 4,000 square degrees of the sky with high sensitivity in three wavelength bands, the telescope can detect galaxy clusters through the spectral distortion they impart on the CMB. Researchers will use the resulting catalog of galaxy clusters to set constraints on the mysterious dark energy that dominates the mass-energy density of the universe and is causing the expansion of the universe to accelerate.

The telescope is looking primarily at the CMB (or cosmic microwave background) of the universe. In particular they’re interested in finding and cataloging very distant galaxy clusters and learning more about Dark Energy, the phenomena that would explain the accelerating expansion of our universe. With a 1 arc minute beam the telescope has a relatively high resolution. The WMAP satellite is also mapping the CMB in the same spectrum (95-250 Ghz) but with far less detail. Ultimately they’re looking at changes in temperature of the CMB radiation reaching us here at Earth – these variations are extremely subtle and the focal plane is cooled down to .25 degrees above zero Kelvin with liquid helium to increase sensitivity. Atmospheric water vapor acts as a barrier to this type of radiation, which makes South Pole the ideal place for millimeter and sub-millimeter astronomy.

This is all very good, but what is the CMB? This can be hard to explain, and harder to conceptualize, but here’s a try…The Big Bang theory states that in the very very early stages of the universe matter was so dense it was plasma, at some point there was an inflation event that caused the universe to expand at speeds faster than the speed of light. The CMB is essentially radiation from the boundary between space and this plasma – it’s the boundary between “empty space” with stars and suns and planets etc, and matter that’s so hot and dense light cannot pass through. This background glow is incredibly unifrom across the sky with a temperature of about 2.7 degrees Kelvin.
The CMB is not what that part of the universe looks like now, but what it looked like 300,000 years after the big bang, when the light we’re seeing today was transmitted. We’re seeing what the universe looked like everywhere before it expanded and cooled enough to have different particles separated by space. We know that light travels at a constant rate (2.9×10^8 m/s, or roughly 671 million miles per hour) – it takes ~8.3 minutes for light from the sun to reach earth, 4.24 years for light from the nearest star to reach our sun, and 100,000 years for light to travel across the Milky Way. So… Looking into space really is looking back in time.

An important fact to keep in mind is that there is no center of the universe. Though the Big Bang theory states that everything started in a condensed state and expanded rapidly from there, there’s no center and no matter where you are, everywhere in the universe will look like the center. No matter where in the sky you point the telescope it will see the CMB at the same distance – kind of like if you were in the middle of a giant bubble, no matter where you looked you would see that inside surface of the bubble the same distance away. To get much useful information from the CMB you need special telescopes, the size of which affects the resolution, but everyone has seen remnants of the CMB without even knowing it. The fuzzy static on TVs (before there was 24/7 digital broadcasting)…that is the TV picking up on this white noise penetrating the universe, this distant radiation from the birth of our universe.

Galaxy clusters are some of the largest physical pieces within the universe. They are so large they create something like a shadow against the backdrop of the CMB radiation. Because of its high resolution the SPT is able to locate, and thus catalogue, many previously undiscovered distant galaxy clusters. Part of their project is to create a database of such features to be analyzed with different types of telescopes in the future.

The second part is Dark Energy – our universe is still expanding, that’s fine, but it’s accelerating in rate of expansion! Theoretically with the amount of material and energy presently known to exist in our universe the effects of gravity should have slowed the expansion by now. It doesn’t make sense. To explain this acceleration there needs be far more matter and energy for the equations to work out. This unknown factor is termed Dark Matter and Dark Energy. NASA provides a much better explanation: http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

The Dark Sector Lab and the SPT in it’s docked position where they can work on the receiver.

The hinge of the telescope and the doors to the receiver area – last year I got to help clean off the grease under and around this part. In the winter the grease freezes and cracks off as it gets pushed out of the hinge, in the summer it thaws and gets very messy.

The base of the telescope – the hole is an access point to the cables and interior of the telescope, the dark piece above is the bearing on which the telescope turns.

Many meters of fiber optic cables run inside the telescope allowing it to turn more than 360. As part of the bearing change last year I got to help unwind and carefully set aside all of these.

The Inside of the telescope – where the cables are usually coiled. This picture was taken last year when the telescope was lifted up to change out the bearing.

The telescope separated to remove the old bearing and slide in a new one. The raised part of the telescope weighed over 65,000lbs!!

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