Goddard Instrument Field Team (GIFT): Goddard Instrument Field Team

January 11th, 2018 by Jake Bleacher

The Goddard Instrument Field Team (GIFT) is a group of scientists and engineers at NASA’s Goddard Space Flight Center as well as their external collaborators. The team focuses on conducting field research campaigns in geologic settings that are analogous to locations on other planets and moons throughout the Solar System. We call these sites “planetary analogs,” and they help us learn how to interpret data from across the Solar System while focusing on understanding Earth better.

Just as we send spacecraft to explore other planets, we have a fleet of Earth-observing spacecraft that provide comparable data about our own world. Every space mission, whether Earth-focused or planetary-focused, provides data that helps us understand the local environment and the history or events that shaped the landscape. Often, though, it seems that for every answer we gain, we develop more new questions.

One way to answer these questions is to develop new instruments. At GIFT, we conduct field studies on Earth to help better inform the development of new instruments that could fly to other planets or could probe our home planet. Earth is but one of a series of planets that formed together in our Solar System, and there are many lessons to be learned about our celestial neighbors by studying our world. We also can learn more about our environment here at home by looking to other planets. GIFT carries out field deployments to a variety of locations to study the local geology and environment and looks at how those rocks might reveal knowledge about past environments. We use the lessons learned during those deployments to help develop new instruments and to improve instruments that will someday explore other parts of the Solar System to try and answer similar questions.

ICESat-2 Antarctic Traverse: On The Road Again

January 2nd, 2018 by Tom Neumann

By the time this hits the press, we will be well on our way. After building the sleds, tuning up the PistenBullys, and going for a couple of test drives around the station, we are about as ready as we are ever going to be. Onward!

Our route travels north along the South Pole Operational Traverse route for about 100km, then turns left and heads out to 87.979 degrees south. 750 kilometers of the great flat white!

While on the road, we will be staying the tents that Kelly described in her last post. Really, tents? Isn’t it cold down there? We expect the daytime temperatures to be in the -20F to -30F (-29C to -34C) range with relatively light winds and sunny skies. These tents warm up nicely in the sun, and will warm up to a good 30 degrees warmer than the outdoor air temperature. That makes the interior a balmy 10F (-12C), which is really not too bad.

Our kitchen tent is the largest tent and will accommodate all four of us. Along the back wall, we have fashioned a counter out of a box and an aluminum kitchen table. The cooking supplies, including a two-burner stove that uses white gas, are stored either in the box, or in the two purple kitchen boxes.  Generally, only one or two of us are in here at a time when cooking, as a little elbow room goes a long way.

Who wouldn’t want to cook in here – look at that counter space!

We each have our own mountain tent for sleeping. It’s always nice to have some personal space, and the multiple air mattresses, foam pads, and super warm sleeping bags make for a pretty comfortable evening. A couple of Christmas lights, some magazines, and it’s home sweet home for the next three weeks.

A super-warm down sleeping bag, plus Christmas lights, make for a comfortable tent.

Days are spent in our PistenBullys, collecting the GPS data of the ice sheet surface using survey-grade GPS systems that will be a critical piece of the ICESat-2 validation effort. We will spend about 300 kilometers around the 87.979 S line of latitude where the ICESat-2 data will be the densest. By comparing our measurements of the ice sheet elevation from the ground traverse, with the elevation measured by ICESat-2 on orbit, we will assess the quality of our on-orbit data and make any corrections necessary. We aim to cover our route in about three weeks and be back here at South Pole around mid-January. Happy New Year, and happy birthday Mom!

We’ll catch you in a couple of weeks!

-Tom and Kelly

ICESat-2 Antarctic Traverse: Merry Christmas from the South Pole!

December 26th, 2017 by Kelly Brunt

Tom and I have been very busy this week, working with our team and with the folks here on station to build the infrastructure associated with our traverse platform.

A nearly complete sled. Modules from left to right: 1) sleep module; 2) cargo module; 3) fuel and generator module; 4) kitchen module; and 5) bathroom module.

We arrived at Amundsen-Scott South Pole Station about a week ago and were extremely pleased to find that the sleds for our traverse were ready for us to start rigging up our tents and gear. The folks here on station have been extremely helpful. They laid out the ‘high molecular weight’, or HMW, plastic sheets that are the foundation of our sled platform. The HWM sheets are pretty cool: they have an awesome coefficient of friction and allow for 10,000 lbs of gear to tow more like 1,000 lbs. And they are wicked slippery – you do not want to walk on this stuff. It’s much safer to walk on the surrounding ice!

A slippery HWM sled, with pallets and fuel drums.

On top of the HMW sheets of plastic, the folks here at Pole attached some special pallets that allow us to strap our gear down to plywood, as opposed to directly to the HMW plastic. Each pallet will contain things like our sleeping tents or our kitchen tent.

The pallets provide a surface area of about 8 ft by 8 ft, so we are making the most of these small spaces. Our sleeping tents (which are just run-of-the-mill mountaineering tents) barely fit on these platforms!

Tent on pallet and HMW sled.

So for added structural integrity, the tents are tied off and bolted (!) to the pallets.

Corner of a sleeping tent, bolted down.

So many folks here at Pole have been enthusiastically helpful to our project. JD, who seems to be a jack-of-all-trades, has visited our site every day and even some evenings. He’s like the South Pole Fairy, who sneaks into our site during the night and leaves exactly what we need, when we need it, including drill bits, fuel, and storage boxes. Darren the carpenter has also been out to our site nearly daily. He has been instrumental in working with our mountaineer, Forrest, to ensure that our gear (especially our tents) will travel smoothly over what might be bumpy terrain.

JD delivers cargo to our site.

By the end of this past week, given the support of folks around town, our two sleds have turned into modest living quarters, capable of withstanding the roughly three weeks of traversing on the ice sheet that lies ahead.

But just when you feel proud of your accomplishments, along comes a not-so-gentle reminder that you are just a light-weight traversing effort: The massive South Pole Traverse rolled into town, delivering fuel to the station. They passed our staging area using Caterpillar tractors, towing hard-sided sleeping and living modules.

A South Pole Traverse (SPoT) vehicle and cargo modules.

And finally, despite our best efforts, we have been slightly delayed in getting into the field. But that meant that we were able to spend Christmas here at Pole, as opposed to huddled together in our small kitchen tent, out on traverse. The station went out of its way to make folks feel warm and festive, even though we are all ~10,000 miles from home. The galley was done up special for the event and the food was simply fantastic.

Christmas dinner at South Pole.

Happy Holidays everyone! We will write again in 2018!

-Kelly and Tom

 

ICESat-2 Antarctic Traverse: South Pole Station: The Last Stop Before the Traverse

December 19th, 2017 by Tom Neumann

After a few extra days in the seaside town of McMurdo Station, we flew on a ski-equipped LC-130 for the sunny environs of South Pole Station, where we had a flawless touchdown on the groomed skiway next to the station. This is our last stop before embarking on the traverse in about a week.  Our main objective here is to prepare our vehicles and sleds for travel, and take some cool pictures.

The team at the bottom of the world.

The Amundsen-Scott South Pole station is located right at 90 degrees south latitude (ok, maybe not exactly there, but the station is within about 100m of 90 S). It’s named for the Norwegian explorer Roald Amundsen, who first set foot here in December of 1911, and for the British explorer Robert F. Scott, who followed closely behind in January 1912. The United States established a station here in 1957 as part of the International Geophysical Year, and it has been continuously occupied ever since. The current station, commissioned in 2008, is the third major station the U.S. Antarctic Program has built here. The prior station (the iconic geodesic dome) was disassembled and sent back to the US.

The elevated design of the station is intended to reduce snow drift, a major consideration when building structures on the ice sheet.

We are here in the height of the summer season, and there are ~150 people on station making the most of the relatively warm weather (-30 C, or -22F) for construction projects, moving cargo, and of course, science projects like ours. In winter, the station is much quieter with around 40 people spending the long winter keeping the station running.

For the first few days we’re here, our main job is to do very little. The South Pole Station sits on top of the East Antarctic Ice Sheet at about 10,000 feet above sea level, which is a big jump from the sea level McMurdo Station. The keys to acclimatization are to drink plenty of water and avoid exercise, though a little walking is fine. After about three days, we will be cleared to move on to more vigorous activities.

The 2017 geographic south pole marker.

There is a marker placed at the geographic South Pole, designed by the wintering crew at the station.  Every year on January 1, the new marker is placed and the marker from the past year is put on display inside the station. Since the entire station (and skiway, and cargo, and traverse vehicles) are on top of the ice sheet, the whole station moves along with the ice. The ice shifts about 30 feet per year toward the 40 degrees west line of longitude where it eventually becomes part of the Filchner-Ronne ice shelf. (Don’t worry though, at the current velocity, it will take tens of thousands of years to get there.)

The perhaps more familiar scene is from the ceremonial south pole – a post with barbershop stripes and a reflective ball on top, surrounded by the flags of nations signing the original Antarctic treaty. The two poles are a few hundred yards apart and are both worth a visit if you find yourself down this way. Tell ‘em Tom sent you.

The team at the geographic south pole: Forrest McCarthy, Tom Neumann, Kelly Brunt, and Chad Seay.

Earlier today, we visited our cargo that we shipped from McMurdo and had a look at our sleds. It looks like everything has arrived, and as soon as our breath catches up with us, we will begin packing the sleds and pitching our tents!

-Tom and Kelly

 

Cyclone Global Navigation Satellite System (CYGNSS): First year anniversary of CYGNSS on orbit

December 15th, 2017 by Chris Ruf

CYGNSS was launched into low Earth orbit on December 15, 2016 at 08:37 EST and today is its first anniversary. The mission has had a very busy first year on orbit, transitioning from an early engineering commissioning phase into the science observing phase in time for the very active 2017 Atlantic hurricane season. The mission was supported during the hurricane season by the NOAA Airborne Operations Center (AOC), which operates a fleet of P-3 “hurricane hunter” airplanes that make reconnaissance flights into tropical storms and hurricanes to observe wind speed and other weather conditions first hand. We worked closely with AOC to coordinate many of their flight campaigns with overpasses of the storms by CYGNSS. They were able to time many of their eyewall penetrations to align closely in both time and space with our overpasses, which helps us train and evaluate our own wind speed measurements As a result, we now have dozens of coincident tracks of wind speed observations through the inner core regions of Hurricanes Harvey, Irma, Jose and Maria. The collaboration with NOAA this summer and fall has been incredibly fruitful, and I and the CYGNSS project team are very grateful for their generous support.

As the 2017 hurricane season winded down, we turned our attention to processing the coincident overpass data and characterizing and evaluating the performance of our wind speed measurements. One example is shown here. On September 24, 2017 at 18:13-18:21 UTC, the CYGNSS FM#2 spacecraft flew across Hurricane Maria.

The red line in the figure shows the track of the specular reflection from transmissions by the GPS PRN#13 satellite.  CYGNSS makes its wind measurements along this track. The black line in the figure shows the flight path of the P-3 hurricane hunter that day. A distinctive cloverleaf pattern can be seen that results from the plane making multiple eyewall penetrations. The colored portion of the P-3 flight path is the leg closest in time and space to the CYGNSS specular point track. The color scale represents the difference in time between the CYGNSS overpass and the P-3 observing time.  With such close coincidence in time and space, we hope and expect that the two measurements of wind speed will be consistent.

The next figure shows the wind speed measured by CYGNSS (blue), measured by the P-3 airplane using its Stepped Frequency Microwave Radiometer (SFMR) wind speed sensor (red), and produced by the ECMWF and GDAS numerical weather prediction (NWP) models (black) along the CYGNSS specular point track.

Away from the storm center at lower wind speeds, CYGNSS and NWP measurements agree well. Near the storm center, CYGNSS responds to the much higher wind speeds. In general, NWP models tend to underestimate peak winds in large storms and this is likely the case here. While NWP models generate winds everywhere, SFMR winds are only available along the portion of the satellite track where the P-3 airplane flew. In the region where coincident measurements were made, CYGNSS and SFMR winds can be seen to agree fairly well. It should be noted that the scatter present in the CYGNSS measurements can be seen to increase as the wind speed increases. This is probably a result of the decrease in GPS signal strength scattered in the specular direction when the sea surface is significantly roughened by high winds. How best to handle this characteristic of the CYGNSS wind speed retrievals will be an important topic of upcoming investigations.

Happy Birthday, CYGNSS!

 

p.s. and just in time for the first year anniversary of CYGNSS on orbit, new science data files using the latest (v2.0) engineering calibration and science retrieval algorithms have just been posted at the NASA PO.DAAC web site.  Access the data by going to

https://podaac.jpl.nasa.gov/dataset/CYGNSS_L1_V2.0

https://podaac.jpl.nasa.gov/dataset/CYGNSS_L2_V2.0

https://podaac.jpl.nasa.gov/dataset/CYGNSS_L3_V2.0

and selecting the ‘Data Access’ tab to reach an FTP link to the data files.

Notes from the Field