Dec. 14, 2006
In my last entry I described the process of getting dressed for Antarctic cold in a small one-man tent each morning. After a sound night's sleep, I emerge into the breathtaking (literally and figuratively) and remarkably quiet white world of Antarctica. I zip up my jacket, adjust my sunglasses and head to the Comms box to make my first utterance of the days, as follows:
SCPZ 131100 175M 16G24 9999 NIL 2/8 1CU3000 1SC5000 M09 Q995 STY C=G H=G JW
Catchy, isn't it? Well its actually full of meaning, and spoken in a language called METAR, known to aviators and meteorolgists all over the world:
Here's a translation:
SCPZ is the not-so-picturesque international designator for our runway which is unpaved and consists entirely of glacial ice (more on our runway in a future email).
131100 means it is the thirteenth day of the month at 1100 Zulu (otherwise known as Greenwich Mean Time or Universal Coordinated Time) which translates into 8AM Chilean time or 6AM in New York, the beginning of the work day for the Comms and Meteorolical staff at Patriot Hills.
175M means that the wind is blowing from 175 degrees magnetic, which is pretty much in the direction of the South Pole. This is the prevailing direction from which the wind blows most days.
16G24 means that the wind is blowing 16 knots and gusting to 24 knots. These winds are known as katabatic winds. They are formed as the cold air on the Polar plateau descends from the Pole's 9,000 foot elevation to sea level, which is the altitude of the Ronne Ice Shelf about twenty miles north of here (open ocean is hundreds of miles away, however; hence no cute penguins anywhere near us). As the cold air descends from the Pole it tends to pick up speed and substantial blows can and do occur here with reasonably frequency. When occuring at night, they are a soporific. The sounds of ice crystals pelting off the fly and the contrapuntal vibrations of the shaking tent are - contrary to expectations - very restful sensations.
9999 means that we can see forever - unlimited visibility
NIL means that we are experiencing no weather events (were it to read +SN - a snow blizzard, it would be time to crawl to our tents and hunker down)
2/8 means that the sky is covered with two-eights cloud cover. Eighths of sky are called "Oktas" down here - don't know the origin.
1CU3000 means that one Okta of sky is covered with a layer of cumulus at 3,000 feet above the ground. In the US we call these "few" cumulus. 2 to 4 oktas are "scattered", 5 to 7 oktas are "broken", and 8 oktas are "overcast". But the international system used by many down here sticks with the numbers.
1SC5000 means one Okta of sky covered with Strato-cumulus at 5,000. Catching on?
M09 means that the temperature is minus 9 degrees Celcius, which is roughly 14 degrees Fahrenheit. Actually very pleasant. The air is dry, lots of solar radiation from the sun, and one always dresses in layers before leaving the tent so there are rarely unpleasant surprises (except when cruising in one of the Ski-Doos, when it can get REALLY cold).
Q995 is the measure of air pressure in hectoPascals, which is a fancier name for millibars. Q stands for QNH, the international designator for barometric pressure. Back in the US, we describe pressure in inches of mercury ("Hg"), but that seems only to be the custom down here at the South Pole Station and McMurdo Base, both operated by the National Science Foundation.
C=G is perhaps the most important part of the report. Aircraft down here don't get to land on gorgeous paved runways with instrument approaches and all kinds of approach lighting or indicators. Sometimes they have no prepared runway at all and they land on snow, or ice. And these surfaces tend to be less than perfect, covered with hard wind-driven lumps of snow called sastrugi and occasionally crevasses. Either can spell disaster for an unwary pilot, particularly when there is an overcast and hence no shadows. So C=G means that the contrast is good, which is as good as it gets. From there, contrast can decline to Moderate, Poor, and the dreaded Nil. As a matter of fact, low contrast resulting from a low overcast is pretty tough on people on the ground, too. Surface irregularities become invisible and tripping is a constant hazard. As my friend and fellow radio operator Alan Cheshire VK0LD reported from our base camp on Mt Vinson last week, "I feel like I am living inside of a ping-pong ball."
The next item, H=G is also important to our pilots. It means that the Horizon is Good. A poor horizon is, as you can imagine, very disorienting. The scale also runs down to Nil.
The report concludes with the initials of the individual who took the weather observation. In this case, it was my good friend Jaco Wium, who sits with me in the Communication box (an upscale shipping container with insulated walls and windows, which the folks around here have taken to calling the "White House"). I will talk more about Jaco and his work in a future letter, but suffice it to say that Jaco, a South African and a seven season veteran here at Patriot Hills, is a maestro at reading downloaded satellite images of Antarctica and can usually be seen taking long strides around camp searching the skies for omens of weather to come.
Oh yes. I forgot a column. It is the one before Jaco's initials. It is entitled "Remarks". Let's recap what you have just learned about our day down here: few clouds, bright sunshine, 14 degrees F, light winds, unlimited visibility and snow covered mountains on two sides and endless ice on the other two, no nasty weather, good horizon and good contrast. My "Remarks" about this?
See you all later. Adam