a sea ice talk...sorry

I get these emails detailing the latest news and information on certain topics that i am interested in. I am such a dull person that these are not about the television or sci-fi news (which is what you would expect). There are on sea ice, Antarctica, polynyas etc. The other morning i was reading through them when a one piece of information got my attention. It talked about sea ice being higher in Antarctica than ever before. There is so much wrong with that statement (which i will detail momentarily). What really annoyed me was that some journalist (and i use the term loosely) would most likely pick that up and run with it. I usually don't worry about what other people and their opinion s (of me or anything else really). This got me really annoyed.

I felt that the statement itself was incorrect unless it was a particular term being used to identify a particular property of sea ice (or such). It wasn’t. I think the person writing it was trying to say that the sea ice around Antarctica this winter was wider in extent than it has ever been. When the term extent is used it refers to the northern edge of the sea ice (as a pack). It doesn’t deal with thickness distribution or ice types rather it is a statement of the boundary for ocean/sea ice.
The sea ice extent is relatively easy to define using remote sensing data of some kind and a methodology for ascertaining the sea ice/ocean delineation. It is much more difficult to say that a certain year is “wider” in extent that another and even more so to identify a trend. There is a limited amount of information to base that on. You can get around this by saying “for as long as records have been kept” or something.

Antarctic sea ice is interesting in that it is sea ice surrounding a continent (as opposed to the generalisation that the Arctic region surrounds the sea ice). The northward advance of sea ice is abated by oceanic and atmospheric properties (and land mass in west Antarctic). To talk about things like width is difficult as sea ice is not a homogeneous entity. Nor does is “sit still” to be measured. You need to find the ice edge to talk about extent. This is tricky. I will try to explain why.

When you talk about sea ice you say thickness (of the ice itself), pack width or extent. I have never heard it referred to as having a height. You can have very thick sea ice compacted to the shore and then the ice breaks up and becomes wider in extent. You are then comparing two different properties of the ice pack. Which was more important? The extent (or ice edge) or the pack density.

The following is an SSM/I image (east Antarctic) from the winter of 1999. The ice edge is where the sea ice meets the ocean. To determine the ice edge is complex. Way more than i want to get into but your more than welcome to look it up.

SSM/I product info: http://www.ssmi.com/

The following plot of ice edge (for the same general area as the map) is the weekly sea ice edge as calculated from the SSM/I data. As you can probably tell there is a lot of variation for a winter. It fluctuates from week to week. Even looking at in time series you get fluctuations and variance. Naturally. What you do get is a general idea of the sea ice extent. You would need many years of data and then work out some averages, means, limits (etc.) to be able to ascertain any definitive changes in behaviour.

Operational products: http://saf.met.no/p/ice/

That is why when you read statements such as the one stated in the opening paragraph you need to realise that the data and any analysis needs to be examined. Thoroughly. You need to know what science is behind it. In general this is a good approach to take in all matters. There is often not a right or wrong answer to a question. Rather there is a “point of view”. You just need to understand it.

BTW this has not been a science lesson. If i wanted to be a teacher i would have become one! I am rubbish at explaining things. This is because my brain runs ahead of my mouth all the time. Also, i have my own short hand. One of the reasons i couldn’t get somebody else to type my notes up. I know that not many people on the planet care about sea ice (and even less about polynyas). However as political people start to use it as a for/against in the great climate debate i think more people should take an interest.

Oh yeah. Merry Christmas and happy holidays.

what i am attempting to start writing about this week...

I sat down to write a simple little science piece tonight. Turns out that the fact i am not a natural writer is never more self evident than when i have something simple to explain. And a saw thumb. Two of them actually. The right thumb injury from a (still unexplainable) sticky tape dispenser incident at work. This is fine because i never use it to type. Ever. The left one however it turns out of DO use. A lot. And it hurts. This injury occurred today as i was preparing food platters for the Christmas party. I was trying to remove one of this plastic lids from a dip. I think it was Hommus. Not that the type of dip is important. Just know that it is taking me ages to type....and i make a hash of spelling at the best of times.

Now to the science bit. Actually, sorry, a bit of background first.

One of the most fascinating aspects of my research has been the breadth of knowledge needed to understand polynyas. This is highlighted in a paper published in Annals of Glaciology (33) called “Effects of Regional Fast-Ice and Iceberg Distributions on the Behaviour of the Mertz Glacier Polynya, East Antarctica” [massom et al]. This paper highlighted some of the many factors that come into play which determine a polynya and its associated measurable parameters (size, width, shape, duration, open mechanism, closing mechanisms etc).

One of the mechanisms is the strong katabatic drainage (sweeping off the ice sheet). These strong winds drive ice away from the coastline (or fast ice, an ice bridge etc). The polynya forms by initially sea ice being driven away from the coast, which leaves an area of open water within which new ice is formed [This new ice is then herded down wind (by ocean, winds etc)].
If you want precise information then try the International Antarctic Weather Forecasting Handbook at:

http://www.antarctica.ac.uk/met/momu/International_Antarctic_Weather_Forecasting_Handbook/index.php
Or read the excellent paper (Chapter 2 details the wind stuff [i know. I amaze even me with how little i sound like a scientist too]):

Bromwich, D. H., 1989, Satellite analysis of Antarctic katabatic wind behaviour. Bulletin of the American Meteorological Society, 70, 738–749.

The thing about these strong winds (Commonwealth Bay is known as one of the windiest places on earth) is that they dissipate not far from land. Given this information what i want to highlight is the difference between having meteorological data from a location n the polynya and from a land based station near the polynya. They do differ and that is why every bit of information helps.

These two images represent meteorological data presented in “wind rose” form. That is the wind speed and direction from a fixed point (the centre of the rose). The first is data collected at the D’umont Durville station (over a 6 week period in winter). This compares to a fixed station further seaward. You can see where the strong winds come from the same direction (in general) however weaker wind systems can be recorded from any direction. This is less likely at the station where there is generally speaking strong katabatic flow. The roses were recorded at the same time.

As the fixed stations have more reliable and longer term data they are what is used most often for other research activities. The difference between the images highlights the natural variability for measuring a phenomenon even (relatively) closely. Say between at station and a ship (in polynya). Also, why drones over a polynya are necessary. And cool:

http://www.disclose.tv/forum/scientific-drones-take-flight-at-earth-s-icy-poles-t13264.html

Another interesting little thing i have been re-reading about (which has nothing to do with my PhD at all) is sastrugi. More pointedly the remote sensing analysis of them (i did this AGES ago so this is all from memory). Now sastrugi (which is the plural form) are sharp irregular grooves or ridges formed on a snow surface by wind erosion and deposition, and found in polar and temperate snow regions. They differ from sand dunes in that the ridges are parallel to the prevailing winds. That means that if you have remotely sensed data you can determine the prevailing wind directions. Cool yeah? Now you just know it is all more complicated than that. It always is.

Anyway my injured digits need to go have a rest. So do i. Also big Bang theory is on the telly.
I might not get a chance to blog before Xmas (unless the weather is really bad and i have to stay inside all week) so let me wish you a happy and safe holiday. XX

[BTW the xmas party was alright. I got to sit on the floor as there weren’t enough chairs. Some might think this not so good but it did mean i didn’t have to talk to people sitting next to me (even though i like them). I am just a bit socially impaired and suck at parties unless everyone else is drunk in which case i don’t feel less shy. I also scored an excellent secret santa gift (this year).]

My Ten Christmas Wishes (for today)

1. I wish that i had more opinions...everyone else seems to have loads.
2. I wish i studied something that people have never heard of and cared about even less. But then what would be the point?
3. I wish i understood politics. But those type of people always put me off. They always seemed to be talking and not listening. Now they run the world....and i worry about who they listen to. I
4. I wish i understood EMT (emission trading scheme) and why some people want it and others are hating on it.
5. I wish i knew why people have to be so mean to each other.
6. I wish people weren’t so short sighted...only thinking of their comfort when we have so much (but who am i to judge - i want lots of useless crap too)
7. I wish i had more ambition. The problem is that i tend to think about doing a good job (with what ever job i am doing) rather than think of a better job to do! but i would like to be someone who is “going places, kicking arse”.
8. I wish i had no regrets.
9. I wish all my favourite tv shows didn’t keep gettin’ cancelled.
10. I wish i could find love. It is not that i am unlucky but i make all the wrong choices for all the wrong reasons (thinking that they are the right ones). I cling to stupid dreams and romantic fiction even when experience has shown me that they are quite unrealistic...and yet still i hope.

So there are my wishes for today. It was quite good to think of what i wish for off the top of my head. Give it a try.

i wandered lonely as an iceberg

I was going to write about how the scientific publishing system works. I was also thinking of maybe doing something about “climate change” versus “global warming” and how they are not interchangeable as terms of reference. Then something cool happened on the news last night. They had a story about this big iceberg B17B that is floating of the Australian coastline (admittedly a long way off...but still).

This news piece showed an interview with Neil Young. It totally freaked me out for two reasons. The first being that the berg itself originated in one of my research study areas and secondly because he was my first boss! Like proper boss. Serious boss. He use to scare the crap outta me to tell the truth.

http://www.aad.gov.au/default.asp?casid=37230

That job was awesome though. I forgot how much i liked it. It was with the glaciology department. Glaciers are what icebergs are calved from. They are totally interesting. My very first project was using computers to analyse satellite data to auto identify (and later track) icebergs. There are a LOT of icebergs and they move in mysterious ways.

One of the things you can do is use them as free buoys. I have an image here which shows the path that individual buoys took that were deployed at the mertz polynya. They cost a lot of money and are hard to deploy (well, tricky). The buoys showed the behaviour of the sea ice (which is what we were interested in) In a similar fashion you can use the bergs to track ocean currents, find grounding zones etc. Like i said cool. Well, i think it is cool.

I loved the research that the glaciology department did (still does). Floating ice shelves. Drilling ice holes to find out what was underneath the floating ice shelves. Accumulation versus loss for given glaciers. In fact studying every little inch of them. That’s what was great about being the computer programmer/scientist. I got to see a little bit of interesting research over a lot of fields.
Until last night i had totally forgotten about that. About all the fun i use to have. I think i am going to make that my new years resolution. To get back some of the wonder and fun i use to have.

If you want to know more about icebergs etc. Feel free to ask. I am in quite a chipper mood.

Tradies have rhythm and soul

At this moment all is quiet. It is late afternoon. I am enjoying the quiet. It won’ last long. I work in a kindergarten which is pretty noisy. For the last couple of weeks at has been quite a bit louder as i have a construction site right next door (1 metre away to be precise). They are madly building a couple of new classrooms. This is all thanks to our fearless leader who gave out LOADS of cash for school works. It helps with the economy because you spread the money around (rather than have it sitting some where) and also employ people (who spread the money around more). It is fantastic. Except we had a lot of rain over autumn so now phase one of building has caught up with phase two....and everyone is very, very busy.

I don’t normally talk about construction (although my dad is a carpenter so i am use to it). In this case i am bringing it up because it is the musical component that has got me intrigued. That’s right. Music. Imagine i work in a school. You have quiet times and noisy times but lately we also have rockin’ times. The workmen (and they are all men on this site) have a stereo blasting out rock tunes all day. Now i am not complaining ‘cause it is quite a good thing while i am on duty at lunch/recess to have something to drown out the sounds of little voices yelling for me (or more often at each other, but more annoyingly AT me).

Now this is not an isolated instance. This music thing. My dad always has music when he works. He has some portable generator thingy to make sure that he can have (a) a cup of coffee and (b) music all the time while working. The painter who does our work likes VERY old vintage crap and the electrician likes soft rock. When they arrive to get a job going it is one of the first things they do – get their music on.

My dad is the worst though. He likes country music *pause* not that there is anything wrong with that. Just he is a bit deaf (all that heavy machinery i’m guessin’) so it tends to be loud. Now i know that he could use an ipod (he has one) but apparently that is a health and safety thing. You need to be able to hear someone yelling at you at all times. Apparently. Safety thing (probably more important reasons but i think yelling “stop that is going to fall and kill you” is right up there – i just need to be able to tell ‘em that coffee is ready).

[BTW he uses his ipod while he watches tv. Just watches it. No tele-text or anything. I am often amazed he even knows what goes on with some programs. Maybe he doesn’t. Maybe the shows are better that way? Anyway. It’s his thing. Yes. He does have a hearing aid but he just prefers it this way. *sigh*]

I only bring this up because my neighbour is doing a reno at the moment. Every night when he gets home he starts work. With a musical accompaniment (and lots of sanding). So this two hour window before he gets home is my only quiet time. I like to fill it by locking myself away in the study and writing a little (rough drafting) before it all gets too much. Actually it is starting to get on my pip really. Can you tell?

Anyway. Only got another half an hour. I think it is going to start raining again tomorrow....and he has to work inside. But then so do it.

Later, K.tsl

Note: What is a tradie? If you don’t know it is an Australian term for a person who works in a trade such as a carpenter, electrician, plumber etc. More specifically to this story it involves those who do manual work, with an open air feel to their working life.