7) nzTABS EXPEDITION: Atmospheric Gadgets

The most obvious thing when we arrived at Sub Camp 2, apart from the delicious smell of dinner, was the array of interesting and alien looking gadgets along the lakeshore. A day spent with Peyman Zawar-Reza and Marwan Katurji, both lecturers at the Centre for Atmospheric Research at the University of Canterbury, and I’ve now got a handle of what they all do.

An array of Atmospheric Research Equipment

An array of Atmospheric Research Equipment

But firstly….. the Dry Valleys are dry! Antarctica is the driest continent on earth, which ironically is 98% covered in ice. The Dry Valleys receive around 50mm of precipitation per year at the valley mouths and almost nothing at the head of the valleys. Why? Because of the rain shadow effect from the Transantarctic mountains. Very simplistically the weather in the Dry Valleys is as follows: In the summer under 24hour sun, when there is regionally calm weather, the winds are driven by thermal circulations which causes up valley winds during the day. During the few hours when the low sun casts shadow into the valleys, the temperature drops a few degrees and there is a weak down valley wind. The major weather comes from the outside, in summer low-pressure systems bring strong winds into the valley, and if dense with moisture, snow will fall. In the winter when the circumpolar vortex strengthens, low-pressure systems cause hurricane strength warm foehn winds to funnel down into the valleys. These are the strong winds that pick up sand and blast and erode the rocks causing sculpted ventifacts.

To understand the biocomplexity of the Dry Valleys ecosystems, it is critical to understand the microclimate. Temperature and water are critical for life. I know that I require water and warmth to live in the Dry Valleys, and a few cinnamon scones! So what causes surface temperature to rise above freezing? And what causes precipitation?

Marwan and Peyman are also looking at finer scale climate questions. They are interested in the atmosphere very close to the surface – below 500m. Specifically wind interaction with topography, turbulence, waves, and the forcings behind them. The Dry Valleys represent a simplified system with no vegetation, which is ideal for theory and hypothesis testing.

They have some serious gadgets, 700 kilos of gadgets in fact. There is the SODAR (sound detection and ranging), and a RASS (radio acoustic sounding system), a surface automatic weather station, and a kite. The SODAR and RASS instruments measure wind speed, wind direction and temperature in a vertical profile from the ground up to 500m every 10 minutes.

RASS

RASS

SODAR Receiver

SODAR Receiver

But the most fun, was flying the kite. A beautiful bright yellow and red 4m kite is attached to a hand winch and flown with instruments attached to validating the temperature profiles taken by the RASS up to 300m. It is labour intensive but necessary for checking the remote sensing gear. Kites work better than weather balloons in windy environments, such as the Dry Valleys.

Flying to kite to validate the RASS and SODAR

Flying to kite to validate the RASS and SODAR

All in all, after a hospitable night at sub camp 2, a jolly good day eating curry, flying kites and playing with gadgets! Back to Main Camp tomorrow.

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Doing the Dobson Dance: Arrival Heights Lab

IPod + Arrival Heights Lab + 1930’s Ozone instrument = a RAD moment. A Random Act of Dancing (RAD). Actually, many RAD moments were had, and mostly on the lab roof.

Arrival Heights is a location on the hill above McMurdo Station, with a 360degree panoramic view of Mt Erebus, Mt Discovery and the Royal Society Range. In late summer it is the best vantage point to watch the sea ice fragment and disperse forming open ocean. Its windy, wild and exposed, but restricted.

The Kiwi operated lab sits prominently within the restricted zone like a fat green elephant, painted Chelsea Cucumber Green. Inside, it is full of obscure, technical instruments, some state of the art and some simply but reliably ancient. Each instrument measures important aspects of the atmosphere. Smoke and mirrors to most, but essential pieces of the puzzle in order to understand the impacts we are having on our atmosphere.

Kiwi Lab for Atmospheric Research

Kiwi Lab for Atmospheric Research

Each day I would bounce the truck up the 4WD track from Scott Base to Arrival Heights to operate these instruments. My favorite being the mighty but ancient Ozone instrument, The Dobson. Favorite, because you get a quantifiable value at the end of each measurement. Favorite, because it involves mechanically moved mirrors. But most importantly, favorite, because it allows me to dance. Dance, while moving the encoder wheel to take a measurement. Dance, while waiting between measurements. And dance, while attaching the sun director onto the roof. The sun director looks like a submarine periscope, but directs the suns rays into the instrument. Two wavelengths of light in the UV range are measured, one absorbed by Ozone, and one not. This gives a ratio, which is converted into a Dobson unit, which is the relative measurement of atmospheric Ozone.

Opening the hatch

Opening the hatch

Along with smoke and mirror instruments, comes magician like scientists. Passionately, they come for short stints to service, calibrate and upgrade their instruments. Behind them trails the media and distinguished visitors for their tour of the new, impressive lab. This involves a little stress on my behalf as tour guide for these complex instruments. But the Dobson never fails to be the star of the show, like a wizened but quirky old man. We can see the mechanical cogs of his brain turning. He was revolutionary in his youth but steadfast in his old age. He, is one that has done a bit of dancing in his day.

Operating the Dobson. Photo by Jana Newman

Operating the Dobson. Photo by Jana Newman

Operating The Dobson. Measuring the Ozone in the Atmosphere. Photo by Jana Newman

Operating The Dobson. Measuring the Ozone in the Atmosphere. Photo by Jana Newman