Archive for January, 2010

Classic clouds #1 – Kelvin-Helmholtz billows

January 21, 2010

My last few posts have been about fairly meaty climate issues or on science policy.  These are important subjects but one of the things I love about atmospheric science is that there are some beautiful things in our skies.  This post is about one of my personal favourites, Kelvin-Helmholtz Billows:

These billows occur when a layer of cloud is found beneath a layer of warmer air and the two layers are flowing in different directions. When this situation occurs, the lower cloud layer is not bouyant so it can’t push up into the warm layer.  However, under the rare circumstances that the two layers are flowing just right, the interaction between the two layers will form an instability and the cloud layer will “break” into the upper layer in the wave-like pattern seen above.  These cloud formations are so rare that they rank as the highest scoring cloud in the Cloud Appreciation Society’s Cloud Collector’s Handbook.  (Confession: I have never actually seen one in the sky.)

But, I have seen one in the lab!  The amazing video below shows an experiment I did during a summer school at the University of Cambridge where the same conditions can be set up.  Enjoy.

[Thanks to Tor Smith (University of Leeds) for the footage and to the University of Cambridge Fluid Dynamics labs for the equipment.]

There are some nice observations of these cloud using the Chilbolton radar either in Chapman and Browning (1997) or on this University of Reading webpage.

UPDATE: I recently saw something that looked like KH billows in the sky where I live. They formed on an aeroplane contrail so maybe this pattern was formed more by turbulence from the plane than atmospheric shear that was already there. Either way, it made my day!

Reference:

ResearchBlogging.orgChapman, D., & Browning, K. (1997). Radar observations of wind-shear splitting within evolving atmospheric kelvin-helmholtz billows Quarterly Journal of the Royal Meteorological Society, 123 (541), 1433-1439 DOI: 10.1002/qj.49712354114

Glaciergate in perspective

January 18, 2010

The story is about a claim in the 2007 IPCC report that the Himalayan glaciers would melt by 2035.  It turns out that the evidence for this claim was from a speculative comment made by a not-very-prominent glaciologist in New Scientist in 1999.  The Times and The Express have gone to town with this story.  So, what does it really mean?

A little bit of background…

To understand the significance of Glaciergate, we first need to understand how the IPCC works.  So, the Intergovernmental Panel on Climate Change (IPCC) is split into 3 Working Groups:

  • WGI: The Physical Science Basis
  • WGII: Impacts, Adaptation and Vulnerability
  • WGIII: Mitigation of Climate Change


Each group produced a separate report in 2007.  They were each about 1000 pages long.  This was the fourth IPPC report round, the others were in 1990, 1995 and 2001.

WGI reviews and synthesises all the work on the physics and chemistry of the Earth system and tries to make projections of how things like temperature, rainfall and atmospheric circulation will change in the future.  I refer to this report a lot in my work as a meteorologist/climatologist.

I know a little about Working Group II – it is written by hydrologists, glaciologists, economists, social scientists and medical scientists – but I have very little idea about what goes on in WGIII.  I also confess that I’ve never looked at the WGIII report.  WGs II and III rely on a certain degree of speculation; it is their business to ask what the world would be like if certain things happen based on the projections from WGI.

Was the Himalayan meltdown a “central claim” in the IPPC report?

The 2035 date relating to the Himalayas appears in one sentence in Chapter 10 of the Working Group II report.  So this is one sentence in nearly 3000 pages. As far as I can see (please correct me if I’m wrong) the 2035 claim was not repeated in the WGII Summary for Policymakers or the overall Synthesis Report.  This was not a central claim.

Given that WGII is speculative by nature then Glaciergate appears to be a reviewing error rather than an attempt to distort the science.  Why the claim was given an implied “very likely” (90% certain) tag is worrying but then this is the first questioning of anything in the report that I can remember since it was published in 2007 – that says a lot for the skill and thoroughness of the report reviewers.

Most importantly, though, the WGII glacier claim changes absolutely nothing about the fundamental science behind climate change that appears in WGI.  This is like saying you wont trust anything in the economics section of The Times because they once printed a football result wrong.  The WGI science is all robust and, if anything, quite conservative in its claims and projections.

Dr Rajendra Pachauri (IPCC Chair) is a former railway engineer with a PhD in economics and no formal climate science qualifications…

Today’s Express also makes this statement as if it undermines the whole of the IPCC.  If anything, it just shows that the reporter has very little idea what the IPCC actually does.  Pachauri has worked in several different scientific disciplines and has headed a large organisation before.  In my mind, that more than qualifies him to head the IPCC.

Anyway, if you’re looking for people with in depth knowledge of specific fields, then there are the WG Chairs.  For example, WGI was chaired by Susan Solomon, who stands a pretty good chance of being awarded a Nobel prize for her work in the 1980s on the ozone “hole”.  Beneath the WG Chairs, each chapter has at least 1 co-ordinating author and 1 lead author.  Beneath them, each chapter also has many contributing authors, all experts in their field.

This attack on Pachauri doesn’t hold up very well.

The revelation is the latest crack to appear in the scientific concensus over climate change…

This claim was made in the Times yesterday, with the other cited cracks being the CRU email theft and something about sea level rise estimates.  This claim seems to assume that “consensus” means that no new work is going on in the climate sciences or at least demonstrates a complete ignorance of how science works.

Things will change in the science, which is exactly why the plans for the next IPCC report (due in 2014) are already well under way!  These are exciting (and, if I’m honest, a little depressing) times for climate science so its disappointing that many people outside the research community don’t want to know about it.

Make science an issue

January 14, 2010

The Campaign for Science and Engineering in the UK (CaSE) last night hosted a debate between the science spokesmen of the three main parties: Lord Drayson (Lab), Adam Afriyie MP (Con) and Dr Evan Harris MP (LibDem).  Firstly, what a great development this is for science policy in this election year – science and engineering have a massive impact in the UK and any effort to “Make science an issue” has to be applauded.  The debate can still be viewed here.

Ok, what about the debate?  Well, the opening statements from Drayson and Afriyie did not fill me with confidence.  Afriyie wants to “get Britain working again” – to me, this sounded like he thinks science in this country is broken.  He probably didn’t mean that and was just mindlessly spouting a party slogan but it’s not how I would have kicked off if I was in his position.  Drayson started off by saying that there “have been no cuts” in the science budget.  I’m sure that most people relying on STFC funding (a topic that was brushed under the carpet in this debate) might find that like a kick in the teeth.  In this company, it was not hard for Harris to tower above his opponents on the scientific, as well as general political, issues at hand.

Given the topic of my previous blog post, I was keen to hear the panel’s views on the “Impact” agenda.  However, as seemed to be a problem with the debate format, the question (“What impact do you expect from government funded research?”) was a bit vague and the initial answer from Drayson was very fluffy.  Harris was negative with respect to the Impact Plan, espousing the merits of blue sky research with unknown impact.  Afriyie picked up the ball and gave more of an opinion on the impact debate and mirrored my own (and the research council’s) views that getting scientists to think about impact at the proposal stage is no bad thing but it should not be used to determine funding decisions.  However, when a question on private/public funding of science came up, Afriyie then seemed all for more applied research to close the “innovation gap” between top quality research and industrial output.

Afriyie later well and truly dropped the ball on the subject of Prof. Nutt.  His view seemed to be that ministers should be free to sack any “advisor” they have for any reason at all!  (This also missed the point, made by @SmallCasserole on the Twitter #scidebate feed, that Prof. Nutt was not a personal advisor; he was the head of a statutory body.)  Afriyie’s opinion seemed even more ridiculous as, in response to a previous question on scientific knowledge within the House of Commons, he had described his passion for evidence based policy.  This evidence can, presumably, be cherry picked from whichever advisor suits your opinion.

Libel reform also got a lot of support from all on the panel.  However, given that the question (as well as most of the momentum behind the libel reform campaign) came from Sense About Science, Afriyie’s assertion that he was making the libel reform case “very loudly within the Conservative Party” rang a little hollow after Zac Goldsmith’s pathetic hatchet job of Sense About Science in the Guardian’s CiF.

So, my conclusion from all this is that Drayson was keen to keep his head down; Harris is clearly a massive bonus for parliament even if his chances of becoming the next Science Minister are relatively slim; and that Afriyie veered from good (repaying student loans for graduates going into teaching, compulsory “science lessons” for all Conservative MPs) to catastrophic (Prof. Nutt, David Cameron’s “zeitgeist” being enough to increase donations to medical research charities).  But I am excited about this interaction between science and politics and really hope that this is widespread and continues all the way to the general election this year.

Britain’s snow and climate change

January 8, 2010

NOTE: This post is from January 2010. I put a temperature anomaly plot from October 2010 here and I’ll do one for November 2010 as soon as the data is available.

I’m sure most of the Brits out there have seen this amazing NASA image of Britain covered in snow.  I love satellite images and use them a lot in my research – they really help me get a grasp of the big picture.

But what does this cold weather tell us about climate change?  Well, if we examine the whole northern hemisphere and look at how the temperatures for December compared to those from the last 30 years, then we get an interesting picture:

So, northern Europe and North America were colder than usual.  But southern Europe, Greenland, the Arctic and north Africa were all warmer than usual.  The situation for January will probably be quite similar.  So, looking at the bigger picture, the recent cold conditions in the UK don’t really tell us much about climate change – we need to look on big scales in both time and area.

Proposed industry standards for the terms “TREACHERY” and “CHAOS”

January 6, 2010

As much as I love reporters using the same terms over and over again, I feel that without any clear definition some of the power of these words may be lost upon the audience.  Therefore, I propose official industrial standards for these two terms.

Treachery

Clearly, in cases where this term is used, the conditions must not be merely and/or obviously dangerous.  The situation should initially appear tranquil – perhaps a sunny day with happy rabbits frolicking on the hard shoulder.  However, over time, the road-based conspiracy to undermine and betray the driver will become clear.  A quiet malevolent laughter will be audible underfoot.

Possible alternatives: dangerous, unsafe, difficult.

Chaos

A long line of stationary cars is clearly not chaotic; this situation is, in fact, relatively ordered.  If the term chaos is used, the following should be expected:

  • At least one overturned, burning car;
  • Screaming women pulling their hair out;
  • Helicopters crashing on the horizon;
  • Complete confusion (as opposed to the clear realisation that you should have stayed at home)

[Apologies to anyone that got trapped or had an accident in the snow.]

Snow in Manchester

January 5, 2010

I’ve not gone to work today.  There’s quite a bit of snow out there.  But why?

Well, the main reason why it’s cold here is because it is winter.  This sounds obvious but it’s worth remembering why it gets cold in winter.  Earth rotates with a tilt so, throughout the year, different parts of the planet get more sunlight.  At the moment, the UK is getting less sunlight so it’s colder.

However, the reason why it is just so cold and snowy right now is a bit more complicated.  If you look at the pressure chart below then you can see that the isobars are almost parallel  from the Arctic all the way to the north of the UK.  This means that very cold air is flowing right to our doorstep.  Brrr!  Watch out further south as the front (the region where the cold air meets slightly warmer air, which produces the precipitation) moves southwards and takes the snow with it.


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