All posts by cathycolless

About cathycolless

Summer Radio Communications Officer at the British Antarctic Survey Rothera base station

Cloud Height Measurements

I came across a curious looking instrument on my walk up to the  Point yesterday and did some investigating to find out what it is.  It turns out to be a cloud height measurer.

Skyward pointing instrument up on the Point
Skyward pointing instrument up on the Point
Backside of the instrument
Backside of the instrument

The instrument like many others had a connection coming back to Old Bransfield House.

Connection back to base
Connection back to base

The aircraft meteorology observations require cloud height measurements. This is quite an art requiring an experienced observer.  At Rothera the cloud heights are provided through visual observations by the Met babes. They do however have this clever instrument to help them.

This instrument fires a beam into the sky and determines the height of the of the base of the cloud be the time recording the time for the signal to bounce back.

This is displayed on a terminal in the  Met Office and observers can VNC connect to the server to view the display from anywhere on station.


30 Years of Weather Balloon Launches at Rothera

Weather balloon data has been collected at Rothera station for more than 30 years, providing a valuable long term data set for climate scientists. There is an office inside the aircraft hanger where the launched instruments are stored and calibrated and a shipping container behind the hanger where the balloons are inflated and prepared for launch. Balloons are launched every Monday, Tuesday, Thursday and Friday morning by the on-duty Met Observer. Anyone on base can meet up with them at the sign-out board at 8.00am and go and help launch a balloon. On the morning I helped it was Petra on duty.

Calibrating the radiosonde
Calibrating the radiosonde

The rubber balloons are stored in a temperature controlled box in the hangar that keeps the balloons at 60c.   The instrument which attaches to the balloon is called a Radiosonde, it has a GPS to track the wind speed and direction and other instruments to measure temperature, pressure and humidity.   Petra calibrated the Radiosonde to the current atmospheric conditions. She then fired up the data collection software on the PC in the hangar and established a connection with the Radiosonde.  She then took the instrument out onto the apron for a quick walk to be sure the GPS locations were being correctly transmitted back to the data collector.

Inflation testing weights
Inflation testing weights

We then moved to the shipping container at the back of the hangar where a pallet of helium canisters are stored. Petra attached weights to the bottom of the balloon then inflated the balloon until the weights just slightly lifted from the floor. She then attached the Radiosonde to the bottom of the balloon and we rolled up the garage doors on the container and stepped outside to release the balloon.

Instruments attached
Instruments attached

The balloon is about the size of a child sized beanbag when it is release but the rubber is not at all taut. As the balloon climbs the atmospheric pressure decreases and the volume of the balloon increases and reaches the size of a semi-trailer before it bursts and falls into the sea.

Balloon release
Balloon release

Once the balloon was released Petra returned to the hangar to make sure that the tracker software was receiving sensible looking data from the balloon. And job done. The data is used by Donald, the local weather forecaster here at Rothera and also sent back to the Met Office in the UK where it is used by modellers and climate scientists.   The data over the past 30 years shows that the temperatures below 8km in the troposphere have warmed and that temperatures in the stratosphere have cooled.  The data also shows that the warming rate at 5km above the surface are three times above the average rate of warming across the globe. Gone ! Gone !

Met Observations for Aircraft

A big part of the job in the tower is passing meteorological observation to aircraft.

Whenever BAS aircraft are flying we collect and pass hourly weather observations for all airfields along the planned and alternative routes for the flight. These help the pilot decide whether to continue with the flight as planned, what altitude to fly at, what find of approach to make when landing. And probably other flying decisions that I don’t know about.

The observation reports typically include, wind speed and direction, contrast, horizontal definition, cloud coverage and heights, temperature/dew-point, present weather, barometric pressure and observer comments.
We pass observations in two different formats:
– A BAS field observation format
– Standard METAR

The content is similar, however there are some subtle difference. In the BAS observations wind directions are given as magnetic bearings where METARs give wind directions in true. The cloud coverage is reported in oktas (eighths) in the BAS observation while a METAR uses scattered, broken or few terminology. And the BAS observations include an indication of the contrast and the horizontal definition which are particularly relevant to polar flying.

BAS Field Meteorological Observations
Hourly Met Observations are taken at Rothera, Fossil Bluff and Sky Blu. The first observation is taken at 700am (1000 zulu). The Fossil Bluff and Sky Blu observations are taken on the HF radio and the Rothera observation we can get from the local intranet.

Hourly BAS Met Observation for Rothera
Hourly BAS Met Observation for Rothera

The BAS observations are mostly passed to flights heading south to deep field locations.
METAR Observations
This is an international standard for aviation meteorological observations. The airfields at Punta Arenas, Marsh and Mount Pleasant in the Faulkland Islands all provide hourly met observations in this format. These observations are typically passed to flights heading North to Chile or Faulkland Islands.

Gash and Scrubout

Everyone on base is expected to contribute to keeping the base clean and preparing food.

Generally people will do any jobs that they see need doing, like helping wash up or clearing a path of snow. Gash and Friday afternoon scrubout are the formalised traditions that help keep the base clean and pleasant.

Food passing line into the  kitchen
Food passing line into the kitchen

Every Friday afternoon a scrubout roster is posted assigning a cleaning job that would take about an hour to each person on base. Between 5-6pm on Friday everyone on base sweeps, mops, vacuums or scrubs some part of the base. There is a bit of a vacuum cleaner shortage on base at the moment and these are highly sought after during scrubout   hour. In the tower we also use this hour to empty our bins, wipe surfaces and vacuum the floor. Moving food from the storage room in old Bransfield house across to the kitchen in new Bransfield house is another common scrubout job. This is done by forming a human passing chain so nobody has to move. In snow this is definitely the fastest method for manually moving stuff.

Gash roster
Gash roster

Gash is a long held BAS tradition. Everyday one person spends the entire day on Gash.  Gash person spends the day washing-up, cleaning the bathrooms, recycling and helping in the kitchen. An important part of the gash tradition is that at meals time gash-person is always served first. At the start of mealtime a queue has usually already formed in the   dining hall. But only after gash-person emerges from the kitchen and takes their food will the first person in the queue take their food. Newbies be warned this tradition is  taken very seriously.

Washing up gash
Washing up gash

The day following your gash day you also help with after dinner washup.  The gash job starts at 8.00am and ends at 8.00pm with a break of about 2 hours in the afternoon between lunch and dinner.

Internet Communications Equipment

Internet bandwidth at Antarctic latitudes is very expensive.  Obviously there aren’t any broadband fibre cables so satellite internet is the only option.   And there are only a limited number of satellites that attempt to provide coverage this far south.

Rothera station has a 2.4m VSAT dish stored inside a radome sitting on the point just behind the base.  The dish talks to the NSS-7 satellite which is a geostationary communications satellite, located in the sky at 0°0′N 20°00′W.  To point the dish antennae at the equator the dish points at a dis-concertedly shallow angle. So low, that if work is required on the roof of one of the station buildings the dish must stop transmitting.

VSAT DIsh Dome
VSAT DIsh Dome

This shallow angle also means that the signal has to penetrate a lot of weather as it glances through the atmosphere for a significant distance. This means that snow and precipitation thousands of miles away from the base can significantly impacts on the service. And it frequently does.
The station telephony system is a Cisco VOIP system that uses the internet connection to carry the incoming and outgoing telephone messages.
So outages cause a disruption to both the internet and telephone system.
Because field parties may try to telephone the station at any time of the night the status of the link is monitored 24/7 by the night watch person. If the link fails in the middle of the night the night watch person will wake up the communications manager.

VSAT Modem
VSAT Modem

The modem and codan equipment to modulate the satellite signal sits in a cabinet in the boot room of the Giants accommodation building.  These manage the traffic and the antennae.

All telephone, data and internet communications use this link
All telephone, data and internet communications use this link

Show Crevasse Trip

The whiteboard in the dining hall at Rothera is always spattered with offers for opportunities to participate in boating, skiing, mountaineering, walking etc.  Yesterday this list went up for visits to the show crevasse. I had heard from others that this was a must-not-miss trip.  I managed to get my name at the top of the list.

IMG_3182So at 1.30pm after Sunday brunch, myself Matt (mechanic), Sam (electronics engineer), Nick (domestic), Seb, Izzy and Becky (i-Star scientists)  assembled at Fooks house to kit out in boots, cramp-ons, helmets and harnesses.

The trip was generously guided by the fabulous Senior Field Assistant Roger Stiltwell.  After helping us all fit our cramp-ons and harnesses, Roger went ahead to dig out the crevasse entrance and Sam led us up the ramp to the crevasse entrance.

Walk up the ramp
Walk up the ramp

The weather deteriorated slightly as we walked up the ramp.  We stopped at the top to watch the Dash 7 land on the base runway bringing 12 more new summer crew.

At the entrance to the crevasse Roger attached a rope to the bumper of the parked skidoo and belayed us all down the narrow entrance into the crevasse.

Lowering into the crevasse

Sam meet us at the bottom of the descent and unclipped us and showed us how to safely navigate within the crevasse chambers. The crevasse has been laid with guide ropes to which we attach. Always attaching a row before detaching from a previous rope. With this system we were to and were able to navigate the crevasse at our leisure.

crevasse3 crevasse4 crevasse5 crevasse6 crevasses2

Flight Following

For the most part, my first week has been spent learning the BAS standard operating procedures and flight following phraseology.

The HF radios are the main means of communications with the aircraft.

HF radios in the tower
HF radios in the tower

Aircraft Departures

The first step in the communications process for the departure of an aircraft from Rothera International Airport is to check
that the appropriate stations are in place to provide fire cover, boat rescue cover, sea ice rescue and runway PAPI lighting checks.

The Standard Operating Procedures (SOP) provide the criteria and actions for all flight following procedures.
For an aircraft departing from Rothera we refer to the SOP to ascertain the SAR cover requirements for the flight taking into account the current conditions, the aircraft ferry weight and POB. Various internal calls on the base telephone or VHF ch1 are then made to check that appropriate, fire cover, boating SAR cover, and sea ice parties are in place to provide SAR cover for the flights take-off.

Once the aircraft is powered on the first call from the aircraft will be a request for radio checks on both VHF and the various HF frequencies that may be used throughout the flight. The radio check frequencies and readabilities are noted on the first entry in the flight following log for the flight.

The next call from the aircraft will be a request for the latest aviation weather reports. In this message we will pass the latest hourly weather from every airfield or field station en-route for both the planned flight and the alternative destinations. So for example for a direct flight from Rothera to Punta Arenas we would pass the latest weather for Rothera (EGAR), Redolfo Marsh (SCRM as alternative) and Punta (SCCI).

The next call from the aircraft will be the taxi call. This message will include the aircraft callsign, runway number, flight destination, POB and fuel endurance. We respond to this message by reading back all of the information and then passing the latest runway and area wind speeds and direction and the latest runway QNH (pressure) to the aircraft.
At this point we log all the details on the flight following log, turn on the runway siren, warning, lights and beacons and make an all stations announcement on VHF CH1 to announce the departure of the aircraft.

Once the aircraft has taxi-ed and lined up on the runway, the next call from the aircraft will be the callsign and rolling call. We simply acknowledge this call by reading back the callsign and replying with roger. As the wheels leave the runway we log the airborne time on the flight following logs. Once the aircraft levels off the pilot will call airborne. Once this call is received we respond by providing the airborne time from the FF log to aircraft. At this point we turn off the runway sirens lights and apron beacon.

I shall write further soon about:

  •  Position reports passed every 30 minutes during the flight
  • Hourly Meteorological Observation Reports from Airfields in the vicinity
  • Trailing Skis calls
  • Final and Circuit calls
  • Landing and Arrival calls
Dash 7 Air bridge flight arriving
Dash 7 Air bridge flight arriving

Induction Days

ajumpseatFlying into Rothera I was invited to take the jump-seat in the cockpit. This allowed me to listen into all the radio communications for the landing procedure.  As you might expect meteorology is the major topic of the aviation communication messages. On the runway we were met by the Base Commander who took us upto the main building, taught us the hygiene procedures in the boot/coat room, assigned us our bedrooms (top bunk, room 19), then took us to the dining room for late dinner. The first day was induction training.  The day started with a generous welcome from the base commander and an explanation of the base routines and systems.  Kenrick the Base Medic then gave us a base tour. The base feels surprisingly spacious, the rooms are large corridors are wide and there is lots of common social spaces. firstaidThe first day of induction training also ended with another session with Kendrick this time on First Aid and familiarisation with the first aid pack contents.  This was largely a walkthrough of the various levels of first aid kits use by field parties.  Kenrick sensibly spent the most time on the items that need to be administered rapidly.  Anaphylaxis shock requires a rapid IM  adrenalin injection so we all practiced this. And pneumothorax, is a collapsed lung.  If air escapes in the space between a collapsed lung and the chest wall,a buildup of air puts pressure on vital organs.  So again needs rapid treatment.

Field Training
Field Training

The second days induction training was field training (tents, stoves, lanterns) in the morning and vehicles driving (base skidoos and gaitors) in the afternoon.  The biggest safety risk to field parties in Antarctica is CO2 poisoning.  So a good part of this session focused on the safe use of stoves and lanterns.  After learning the basic skill, James took us up the ramp along the flagged recreation areas and explained the safety boundaries. base-snowcat The second part of the field training involved a tour of the travel zone boundaries. base-nick Tent pitching and snow camping were also covered in the field training.  We pitched this North Face tent but most of the field kits seem to be using Terra Nova Qasar Super edition tents.   These are fitted with addition flaps for snow weighting. Vehicle driving training was the final session. There are a few gaitors and skidoos on base that can be used for base work. Jack took us through pre-start checks, driving and fueling the vehicles. To check us he asked each of us to driving the skidoo up and down the the ski ramp opposite the base.

Gaitor Training
And Skidoo training
And Skidoo training

Flight to Punta Arenas

I am on the way….

BAS  provide a free mini bus from Cambridge to Heathrow and that would have been the ideal way to get to Heathrow.  But I am taking a huge bike with me too big for a mini bus, so we cycled to Cambridge train station, caught a train to Kings Cross, then followed the GPS to cycled 7km across London to Paddington, to catch the Heathrow Express. So  far five changes and not yet left the UK Cambridge>Stevenage>KingsCross>Cycle>HeathrowCentral>Terminal 5IMG_2005 IMG_2007 Bicycle included, I checked in more than 50kg of luggage, 22kg in the kitbag, 12kg in my luggage and 21kg for the touring bike.  They tagged the luggage all the way through to  Punta Arenas but told me I would need to collect and re-check it at Santiago for Chilean customs.  I paid £205 in excess baggage which was not  as much as I had expected.

50kg of luggage tagged through to Punta
50kg of luggage tagged through to Punta

Yes, this is a ridiculous amount of luggage, but in my own defence this is stuff not just for my stay in Antarctica but also full cycle camping touring kit for a post deployment tour in North America. A lot of this stuff I will leave in Punta Arenas while I am south. There were eleven of us from BAS in this group headed for Rothera, with Andy who is heading south to lead a traverse party ably leading our group.

Flight number 1 Heathrow to Madrid. Surprisingly good egg sandwich.
Flight number 2. 13 hours overnight Madrid to Santiago

The views over the Andes coming into Santiago made a great way to wake up.

Morning views of Aconcagua coming into Santiago

At Santiago I needed to collect all the 50kg bike and baggage and drag it through customs and re-check it for the domestic Punta Arenas flight.  I had been dreading this but I got loads of help from the super lovely people in our group.

We had about 4 hour at Santiago airport before boarding the flight to Punta at 1.00pm.  Even better views of the Andes and Lakes District on this flight.  The plane stopped and did some quick passenger changing Puerto Montt and I managed to nab a whole row if seats, so manage a short sleep.

Flight to Puerto Montt
Flight to Puerto Montt – Flight  3

At Punta the BAS agency staff from Agunsa gave us a friendly welcome met at Punta  airport. They  collected up all our passports and the important little carbon copy slip of paper Chile immigration had given us at Santiago to arrange the immigration exit stamps before the BAS Dash 7 flight tomorrow.  By 7.00pm we were at the hotel and by 8.00pm we were out for dinner.  Chile is on the same time zone as  Rothera GMT-3.

Pilgrim loves looking out the window ! Punta Arenas.
Pilgrim loves looking out the window ! Punta Arenas.
Punta Arenas
Punta Arenas


Had a great sleep in the comfy and quiet hotel in Punta.  All being well tomorrow we fly on to Antarctica on the BAS flight.