The pathological geomorphologists have been running a series on dune-river interactions recently, so I wanted to add this most recent TERRA image of the Queensland floods. The floodwaters in the Diamantina (top) and Coopers Creek (above centre) sections have now reached the longitudinal dunes of the Simpson desert. The full image has 250 meter pixel size, so it is easy to see individual dunes (which are generally a few hundred meters across the base and a few to tens of km apart). You will have to click the link for super high res goodness and detail- clicking the image only gives a medium resolution image.
These images are updated daily (weather permitting), so you can hop backwards and forwards to measure the progress of the flooding over the past month or so.
Monday, March 29, 2010
Sunday, March 28, 2010
This is the accretionary wedge question of the month. It relates to our jobs as professional geoscientists. However, geologists are humans too. And we have all the complications and work-life interactions that constrain other humans. So right now, the answer to this question is very simple:
I am on paternity leave. I've put my isotopic ratios and crystal chemistry aside for now, to care for LLLL-Y, a little man who is about 1010 times younger than your average zircon. This involves changing nappies, settling, and generally attending to any extraneous needs of his that don't require boobs. When I'm not doing that, LLLL-X still requires all the love and attention that she took for granted three weeks ago.
The zircons have been sitting around dutifully trapping the daughter products of actinide decay for hundreds of millions of years. They can wait until next week.
NASA's Earth Observatory has been posting some great pictures of the Queensland floods. East-Central Australia's ephemeral rivers have very low gradients, so floods can be tens of kilometers wide while being only a few meters deep. Using the correct spectral band, this standing water is easily visible from space. The flooded rivers in the above picture are (from West to East) The Georgina and Diamantina rivers, which flow together in Northern South Australia before entering Lake Eyre; Coopers Creek, which independently enters Lake Eyre, The Bulloo River, which is a closed drainage all of its own; and the various tributaries of the Darling, which runs south into the Murray river and eventually into the Great Australian Bight.
The Earth Observatory has a page showing a series of images from both this and previous floods.
When I was in exploration, we had a few tenements in Western Queensland. We were lucky enough to work some areas after moderate rain events, and got to see what happens when these places fill up with water. The following images are from the Georgina basin, and show how the Eastern Simpson desert changes with rain.
The characteristic longitudinal dunes are present in all
images, as low lines of orange sand (often overgrown).
When dry, there isn't much there aside from spinifex, mallee scrub, and arid animals (which are interesting in their own right).
When it rains, though, the waterbirds are spectacular. These are brolgas, but we also saw ducks, herons, gulls, and all sorts of other things which I can't identify.
The Real Dirt has this report on flooding of the Mulligan river, a Georgina tributary near where the above "dry" photo was taken (We had the uranium exploration rights to parts of their nature reserves). It is well worth reading.
Update: The most recent image is here.
Wednesday, March 24, 2010
There is a malicious rumor stalking the geocybersphere that overworked professors, desperate not to be seen using wikipedia as a source, have decided to grading-related research using twitter. As a twit-free blogger, I am not in a position to determine the veracity of these reports, but a little birdie told me that non-climatologist rockheads were looking for information on the greenhouse gas properties of ozone.
Ozone absorbs IR in a portion of the spectra that is generally not absorbed by many other gasses (figure 1, figure 2), and thus is a greenhouse gas. More importantly for those of us who have given up on this planet and are looking for the next best thing, the ozone IR peak is considered to be a prime candidate for exobiological IR spectroscopy, which will be great once we find a terrestrial planet cool enough to host water.
figure 1: Ozone FTIR spectra (from here).
Figure 2. Terrestrial IR emittance. Valleys indicate atmospheric adsorbtion. Note that O3, H2O, and CO2 have very different atmospheric abundances. click image for more readable version. From here.
In the mean time, the effects of ozone on the radiation balance of this washed-up blue dot are available in a source only slightly less controvercial than twitter or wikipedia:
The IPCC fourth assessment report.
Section 184.108.40.206 covers stratospheric ozone (the 'ozone layer').
Section 220.127.116.11 covers tropospheric ozone (smog & other air pollution ozone, incl. lightning).
The tropospheric ozone issue is complicated by the fact that most ozone-producing processes also produce CO and the various nitrous oxides (NOx). But the GHG contribution from tropospheric ozone appears to be moderate and positive (a mean estimated forcing of +0.35 W/m2, with asymmetrical error envelope of +0.25 to +0.65 W/m2)
The stratospheric ozone calculation is poorly explained. They don't actually give the total forcing of the pre-CFC (intact) ozone layer, the current one, and use the difference. Rather, they try to estimate the change in forcing directly, including the change in all the chemicals that cause ozone destruction (which are also GHG's). This is confusing, since those gasses were already addressed in section 2.3.4: Montreal Protocol Gasses. So the Montreal gasses (or at least the sink that is the ozone destruction reaction) appear to be counted twice. Their final estimate is that ozone depletion has had a cooling effect, with a forcing of -0.05 ± 0.1 W/m2.
Note that the baseline year for stratospheric ozone is 1979, which may or may not be appropriate for pre-industrial levels.
For some reason ozone is not listed in table 2.1, but based on these numbers, it should be somewhere between the 2nd and 5th most important gas in terms of total anthropogenic radiative forcing.
What I want to know (and is not addressed in this part of the IPCC report) is whether or not Antarctic ozone depletion is what has allowed that part of the planet to warm much more slowly than everywhere else over the past 30 years. Bueller?
Paranoid readers may think that wanting to know the total forcing of the stratospheric ozone layer is a precursor to a mad geoengineering scheme that will eradicate all terrestrial life in exchange for 50 more years of coal profits. That is always an option, of course. But there is a far more interesting application relating to a much more exciting period of geologic time.
In the Neoproterozoic, atmospheric oxygen is thought to have increased rapidly as the ocean transitioned from anoxic at depth to entirely oxidized. Stratospheric ozone is formed from atmospheric oxygen. So I am wondering if the greenhouse contribution from a growing ozone layer would be strong enough to be a contributing factor to the end of the Cryogenean glaciations at the Ediacaran/Cryogenean boundary. Anyone have any idea if that's plausible?
Sunday, March 21, 2010
Lake Eyre is the terminal playa for Australia's largest drainage system. Most of the time, it is a salt pan, with or without some briny pools at one end or the other. However, every few years, it floods to a few meters depth, and a few times a century it fills up. It's ephemeral nature does not prevent people from taking an interest in sailing there. The Lake Eyre Yacht Club has a website detailing information on the current lake status, tips for navigating on remote, supersaturated salt water, and everything else potential mariners might want to know. Geoscientists often justify their work in terms of disaster mitigation, economic activity, or other serious benefits. But this shows that the layman's ability to use geospacial data is limited only by his imagination. There's a huge amount of hydrology and remote sensing science that goes into trying to predict lake levels. But I doubt any of the scientists who built these tools imagined that they would be used for catamaraning in the middle of a desert.
Monday, March 15, 2010
Over at the political stats blog fivethirtyeight.com, guru Nate has wordled responses from a recent poll on Healthcare. While this is interesting, I don't think it is the best way to look at the data. So here are differential wordles for the For and Aganist responses.
Cut responce text (unedited) out of spreadsheet and into text file, then into wordle. Get word frequencies, and copy/paste to excell. Eliminate common pronouns and prepositions. Cut off words with frequency less than 10. At this point, there were ~11% more against words than for words, so frequencies were normalized. Against words were reculled at 11, and normalization was redone (it changes by less than 2%). For and Against totals were subtracted from one another, and wordles were made from both sides for whichever had more of a given word.
Note that I have left many common words in to see if their frequency is different between the two camps.
Saturday, March 13, 2010
I took LLLL to the zoo last spring, and there we noted the following sign on the Monkey enclosure near the café:
Please do not feed us. We are on a special diet.
I didn’t realize that monkey diets were drastically different to humans ones, so I took a look at what they were eating:
Tomato, zucchini, melon, apple.
This didn’t look particularly special to me.
So I shrugged and went into the café.
I scanned the menu there: hot dogs, cheesecake, coffee, ice cream, meat pie, but not many vegetables. And I started to wonder.
Who was misfeeding whom?
Thursday, March 11, 2010
Saturday, March 06, 2010
Due to my three big summer projects, I wasn’t able to put up a proper maximum sea ice betting pool like I did for the Northern summer. But using the theory that late is better than never, here you go. Rules are the same as the last contest. Enter a value and sigma, to define a Gaussian curve. Person with the highest value at the final ice extent (from JAXA's AMSR-E webpage) wins.
Contest is open immediately, and closes the first time I get to blog after the second child is born, OR the first day the JAXA record drops for a second consecutive day. Whichever comes sooner. Note that sea ice could max out anytime between now and the end of March. Ditto with the baby coming.
Hopefully the skillful forecasters will outperform the half-assed guessers, compared with the three-month-out summer forecast of last year.
Running with the theme, the prize is that the winner gets to pick a topic, about which I will write a half-assed post.
I have already announced summer projects one and two that have been eating up my time. This is number three. Over Christmas break Mrs. Lemming pointed out that I was spending more time preparing for chickens than for our second child. This would have been funnier if it wasn't so true.
The poor girls came home in the rain yesterday- I don't know if they have ever been outside before, but they were certainly bewildered by not being in a cage with dozens of their sisters, and they had to be shown into the hutch to get some cover. When the sun came out this afternoon they perked up a bit, though. And by evening they had discovered the delicacy that is fresh green grass.
Friday, March 05, 2010
There is an internet petition afoot to make "hella" the official SI prefix for 1027. In one sense, this seems silly- a hellameter is several times the size of the observable universe. But there is at least one application for which this suffix would be useful.
Currently, one of the most exciting areas in all of science is the discovery of smallish planets orbiting other stars. By smallish, I mean smaller than Neptune. But while there is a factor-of-fourteen mass gap in our own solar system between Uranus and Earth, in the rest of the galaxy this gap does not exist, and planets occupy most of that mass range.
Traditionally, most planets have had their mass compared to Jupiter. While this is fine for gas giants, there are a couple of problems when applying it to smaller planets. Firstly, you end up with lots of zeros in front of your number: 0.003 is a bit awkward. Secondly, nobody really has a good feel for how massive a planet is.
The hellagram solves both of these problems. Earth is a shade under 6 hellagrams. Neptune is a shade over 100. Jupiter, the big boy of our solar system, is about 1900. If we assume that Mars is just a bit too small to maintain active geologic processes up to the present day, then 1 hellagram becomes a good ballpark lower bound for active planets. It is also close to the detection limit for Kepler, the most sensitive planet hunting program now operating.
The hella- project is being run out of one of the University of California campuses. And the UC system is a world leader in exoplanetary detection and characterization. So if they get on board the hellabandwagon, the hellagram has a good shot at entering common scientific usage. And that would be hella cool.
The mass of known sub-Neptune planets, in various units:
|GI 581 e||11.6||1.94||0.00610|
|61 Vir b||30.4||5.09||0.0160|
|Gi 581 c||32.0||5.36||0.0169|
|GJ 667C b||34.4||5.76||0.0181|
|GJ 433 b||36.1||6.04||0.0190|
|Giliese 876 d||38.0||6.36||0.0200|
|HD 40307 c||41.0||6.87||0.0216|
|Gl 581 d||42.4||7.10||0.0223|
|HD 181443 b||45.2||7.57||0.0238|
|HD 1461 b||45.4||7.60||0.0239|
|55 Cnc e||45.6||7.63||0.0240|
|HD 285968 b||50.3||8.43||0.0265|
|HD 40307 d||54.7||9.16||0.0288|
|HD 7924 b||55.1||9.22||0.0290|
|HD 69830 b||62.7||10.5||0.0330|
|HD 160691 c||63.1||10.6||0.0332|
|GJ 674 b||70.3||11.8||0.0370|
|HD 69830 c||72.2||12.1||0.0380|
|HD 4308 b||76.9||12.9||0.0405|
|HD 125595 b||85.5||14.3||0.0450|
|Gl 581 b||93.4||15.7||0.0492|
Thursday, March 04, 2010
A tall, skinny man just East of Virginia said:
At this second appearing to take the oath of the presidential office, there is less occasion for an extended address than there was at the first. Then a statement, somewhat in detail, of a course to be pursued, seemed fitting and proper. Now, at the expiration of four years, during which public declarations have been constantly called forth on every point and phase of the great contest which still absorbs the attention, and engrosses the energies of the nation, little that is new could be presented. The progress of our arms, upon which all else chiefly depends, is as well known to the public as to myself; and it is, I trust, reasonably satisfactory and encouraging to all. With high hope for the future, no prediction in regard to it is ventured.
On the occasion corresponding to this four years ago, all thoughts were anxiously directed to an impending civil war. All dreaded it--all sought to avert it. While the inaugeral [sic] address was being delivered from this place, devoted altogether to saving the Union without war, insurgent agents were in the city seeking to destroy it without war--seeking to dissole [sic] the Union, and divide effects, by negotiation. Both parties deprecated war; but one of them would make war rather than let the nation survive; and the other would accept war rather than let it perish. And the war came.
One eighth of the whole population were colored slaves, not distributed generally over the Union, but localized in the Southern part of it. These slaves constituted a peculiar and powerful interest. All knew that this interest was, somehow, the cause of the war. To strengthen, perpetuate, and extend this interest was the object for which the insurgents would rend the Union, even by war; while the government claimed no right to do more than to restrict the territorial enlargement of it. Neither party expected for the war, the magnitude, or the duration, which it has already attained. Neither anticipated that the cause of the conflict might cease with, or even before, the conflict itself should cease. Each looked for an easier triumph, and a result less fundamental and astounding. Both read the same Bible, and pray to the same God; and each invokes His aid against the other. It may seem strange that any men should dare to ask a just God's assistance in wringing their bread from the sweat of other men's faces; but let us judge not that we be not judged. The prayers of both could not be answered; that of neither has been answered fully. The Almighty has his own purposes. "Woe unto the world because of offences! for it must needs be that offences come; but woe to that man by whom the offence cometh!" If we shall suppose that American Slavery is one of those offences which, in the providence of God, must needs come, but which, having continued through His appointed time, He now wills to remove, and that He gives to both North and South, this terrible war, as the woe due to those by whom the offence came, shall we discern therein any departure from those divine attributes which the believers in a Living God always ascribe to Him? Fondly do we hope--fervently do we pray--that this mighty scourge of war may speedily pass away. Yet, if God wills that it continue, until all the wealth piled by the bond-man's two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash, shall be paid by another drawn with the sword, as was said three thousand years ago, so still it must be said "the judgments of the Lord, are true and righteous altogether"
With malice toward none; with charity for all; with firmness in the right, as God gives us to see the right, let us strive on to finish the work we are in; to bind up the nation's wounds; to care for him who shall have borne the battle, and for his widow, and his orphan--to do all which may achieve and cherish a just and lasting peace, among ourselves, and with all nations.
I can't help but think of this speech every time I hear an athlete thank God for granting him or her victory in some far less momentous contest.
Posted by Chuck Magee at 11:42 PM
Wednesday, March 03, 2010
There have been some murmurings around the internet that the new National Australian curriculum, which was unveiled on Monday, will have a strong aboriginal culture theme imprinted into the science curriculum. In his generally positive take on the curriculum as a whole, Sydney Morning Herald blogger Tim Hawkes says:
Somewhat less defensible, in my view, is the inclusion of indigenous understandings of the natural environment in science. Although fascinating, I think this topic is better dealt with in an area other than science which, quite properly, should be dominated by the skills of empirical observation and measurement.
So what does the curriculum actually say? This is not a particularly easy question to answer. The new curriculum information is hosted at http://www.australiancurriculum.edu.au/
Some government websites here are quite well designed. Immigration and weather are particularly good. This one is a nightmare. The details to which I am assuming Mr. Hawkes refers are accessible via the following:
1. Register with the website.
2. click the explore tab
3. click the science curriculum
4. under the default settings, “Science as a Human Endeavour” should be the middle column. In years one through ten (but not kindergarden), this will contain several one-sentence sub-sections, one of which is “Science and culture”
5. click the green feedback button.
6. in the pop-up that appears, click the “content elaboration” tab.
The text that appears cannot be cut and pasted, and is not googlable. If there is a less convoluted way of finding it, I don’t know it. So I have had to resort to screen-capturing all 10 science and culture content elaborations. Where scrolling was necessary, screen captures have been stitched. Otherwise, this information has been in no way edited. I apologize if the text is too small to read without clicking through to the full-sized image. If that is not legible either, say so and I'll type transcripts if I ever get the time.
So, gentle readers, are the following appropriate for a science classroom? Discuss in comments.
Creative common licence and distribution restrictions can be found here. As far as I know, I comply.