Winter Over Blog #8 2016

Yes the recreation blog is still a work in progress but couldn’t help but mini blog about the coming of the sunrise. Officially on 19^th August but didn’t get to see it till 22^nd August.

New Sunrise

Hey got so enthused even dared to elbow out Wanaka’s daily photo spot on TVNZ weather with a picture of the sunrise on the Ross Sea ice. So Antarctica trumped Wanaka for that spot on 22^nd!

New Sunrise on Ross Sea Ice 22 August (well officially 1^st Sunrise was 19^th but clouds did not play ball for a couple of days)

Nacreous Clouds

With the coming of daylight also heralded a display of nacreous clouds. No I had never heard of them before either – but they are stunningly beautiful like silky mother of pearl.

However they aren’t just a pretty face but like sirens of the skies send a rainbow message that we (humans) need to heed. Why? Because they and humans in combo affect the ozone layer protecting the earth.  Sh*t, I am sounding like a greeny the only thing stopping me from becoming a tree hugger is “aren’t any trees down here”. A worrying thought on what will happen in mid Oct and return to NZ?

At end of blog have inserted an article on what I found via internet about nacreous clouds and just in case you are as curious as I was about these clouds – read on.

Narceous clouds

Ozone hole over Antarctica

New Comers

Yes with the new dawn a new bunch of new comers arrive on first flights down. I managed to sneak a ride out in the Hagglunds to go a collect the few Kiwis (in orange suits) amongst a sea of red (suits).

Rather the beginning of the end of the winter-over stint, with the influx of new people starting and the sun. So here’s a few picks of what is called “winfly” (winter flights) – technically a series of flights due over a week bringing in some 200 people into McMurdo (and 7 kiwis) though some only for a few days.  Some that were due on a Saturday flight arriving on a Tuesday and had to get their work completed before flying back out on Friday (so compressing a planned week of work into 3 days) together with a familiar aircraft issue of luggage arriving on a later flight, which for some was a day after they had departed back to NZ!

All working to get the base ready for the main influx in early to mid-October.

Appendix

1, Nacreous clouds: stunningly beautiful, surprisingly destructive.

Behind their iridescent, rainbow-colored façade, these clouds are wreaking havoc on our atmosphere. They’re a major contributing factor in the formation of ozone holes in the Arctic and Antarctic.

Nacreous clouds develop in high latitudes – 60 to 90 degrees – of the Northern and Southern hemispheres. In addition to forming at high latitudes, they exist only at high altitude. Nacreous clouds form in the stratosphere, at 70,000 feet or above — more than twice as high as commercial airliners fly. This is also where the ozone layer resides.

Clouds generally don't form in the stratosphere. Typically, it’s far too dry there for ice crystals or supercooled water droplets to develop. But nacreous clouds are different. They're a mixture of supercooled water, ice crystals and nitric acid.

During winter, when there’s little sunlight in the Polar Regions, the stratospheric polar vortex strengthens and locks out warmer air. This creates extraordinarily cold temperatures in the stratosphere. At this juncture, water vapour in the stratosphere changes to a supercooled liquid or ice crystals.

At this point, the atmosphere is still unaffected by the clouds, but atmospheric chemistry will change that.

Vast quantities of chemical compounds, like hydrochloric acid and chlorine nitrate, are the result of the breakdown of chlorofluorocarbons (CFCs). How did these chemicals get into the stratosphere? In a word: Humans.

The nacreous clouds provide an ideal surface for chemical reactions that involve CFC-derived compounds. As these compounds interact with nacreous clouds, chlorine gas is released.

As soon as sunlight comes into contact with a chemical compound, the molecule absorbs energy and enters an unstable state, initiating a photochemical reaction. In the case of chlorine gas, a bond between two chlorine atoms, photochemical processes lead to the release of elemental chlorine.

This is where the atmosphere is affected: Chlorine gas kills the naturally occurring ozone in the stratosphere. One chlorine atom can destroy thousands of ozone molecules due to the catalytic nature of the reaction. This means chlorine acts as an agent to accelerate the breakdown of ozone.

While the hole in the ozone layer is still prevalent at certain times of the year, due to the reduction of CFC output in the 1980s and early 1990s, stratospheric ozone concentrations have been on the rise. But don’t pat yourself on the back too soon just because you switched from a spray on CFC laden aerosol deodorant to roll on as your contribution to fighting the ozone hole. Why? Well like the plastic in our oceans CFCs last a long time in the atmosphere: up to 100 years. So while they may be beautiful, nacreous clouds will be harming the ozone layer well into the future.