William Ingram

I'm 50% employed by the Met Office Hadley Centre, & 50% by the climateprediction.net project in AOPP. I spend some of my time in Oxford, some at the MOHC unit in Reading & a little at MO HQ in Exeter.

My research interests are all to do with understanding the basic physics, mostly of the atmospheric response to climate change. This is of course the most relevant to society & policy-makers, but is also scientifically interesting, as it's looking at the response to a perturbation that indicates what the controls on the system really are. Much of my work uses General Circulation Models (GCMs), the most detailed & physically-based models of climate.

The research area I have worked on the most is the water vapour feedback on climate change. Water vapour is the most important greenhouse gas in our atmosphere, but its concentration is set by saturation at some point in the history of the air concerned, & the saturation vapour pressure increases strongly and quasi-exponentially with temperature. (The strength of this dependence is due to the high latent heat of vaporization, which in turn is due to the strong hydrogen bonding in the condensed phases, as are the high melting & boiling points for the molecular mass.) So we confidently expect global warming or cooling to increase or decrease its concentrations and so the greenhouse effect, adding to the warming or cooling - a positive feedback. Numerical calculations for decades have agreed that this roughly doubles climate sensitivity.

In recent years my work on the water vapour feedback has mostly been about the "partly-Simpsonian" approach. So naturally I have far too much to say about that to fit on this page. Apparently this website will eventually allow me to add a page about that: for now colleagues should be able to read http://www.atm.ox.ac.uk/user/ingram/pS.html & other people should be able to download it from pub/user/ingram/pS by anonymous ftp into ftp.atm.ox.ac.uk. (Let me know if it consistently doesn't work.)

I have also been involved in the formal detection & attribution of climate change. Colleagues know much more about it, but some people may find an introductory review I wrote, concentrating on the solar effects, some use.

One older paper of mine that may still be of interest looked at the impact on the water vapour feedback of changes in vertical resolution in a GCM. In the real atmosphere water vapour concentrations often show a lot of fine-scale variation in the vertical which is inevitably smoothed out in GCMs - & some people thought this cast doubt on the GCMs' water vapour feedback. I don't think this ever seemed plausible to people who understood the radiative physics, both because the total heat radiated is very much an integrated, smoothed, function of the profile, and because the near-logarithmic dependence on water vapour concentration of LW emission at water-vapour-dominated wavelengths means that the radiative change per unit warming hardly depends on the actual amounts, but rather on the fractional change in the amounts (determined by the quasi-exponential dependence on temperature mentioned above). But I showed that at least in one GCM, order-of-magnitude changes in vertical resolution didn't much change the water vapour response to idealized global warming.

One project I have been wanting to get done for a couple of decades is described on the "teaching" tab.

My best-known publication - most-cited, anyway - was led by my colleague Myles Allen, a review (with some original material) in Nature "Constraints on future changes in climate and the hydrologic cycle".

I don't do formal teaching (well, only the odd lecture for someone else on a day they had to be away).

But I do supervise research students.

One project I have been wanting to do for a couple of decades is finally under way:
The errors in GCMs (and indeed the related models used for weather forecasting) are often a matter of features being displaced. This is a particular problem for rainfall at low latitudes because it has smaller scales than e.g. temperature & because the physics that creates it has strong positive feedbacks on location. And of course much of the impacts of climate change will be felt through moisture availability rather than just temperature.
Adam Levy is now working on ways to correct these errors of location, adapting software used to line up ("register") brain scans for quantitative analysis, supervised by Myles Allen & me here in AOPP, and Mark Jenkinson, who is a leading authority on such software, in FMRIB. The point is not just to say "Oh, the error would be less if this rainband were in the right place like this" (though quantifying "doing the wrong thing" v "doing the right thing but in the wrong place" may be useful to GCM development work), but to apply transformations derived from the present-day mean to both projections of the future & simulations of the past. We hope that in both these cases it will bring the GCMs together. This will make the results more consistent and physically-based, so reducing uncertainty for the future, and increasing potential to detect past changes in observations.
Preliminary results using the existing code show it basically works, but of course rain is different from brains so various bits of new code are needed to do the job properly.

I'm also now supervising Richard Millar, who will be working on geo-engineering, specifically SRM (solar radiation management) using stratospheric aerosol.

My other employer, their library catalogue & observational data.
Part of the point of my being in Oxford is to help communication between Oxford & the MO, so if you're a colleague at either end &, say, are wondering if there's someone at the other end worth contacting about something, do please ask me.

Our learned society is The Royal Meteorological Society. It does a lot of good stuff, & I must take advantage of it more.

The authoritative sources of information on climate change are the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Inevitably they are somewhat bureaucratic, & never quite up to date, & may not cover well-established science that hasn't been seen as policy-relevant. They're supposedly aimed at non-specialists but only the "summary for policy-makers" really is. After the 1st they are supposed to be updates, so the 1st may be the best if you want the basics explained.

Here is Mike McIntyre's summary of how & why to be lucid.

Even if you don't have any interest in the history of our science for its own sake, sometimes the original paper is as clear as anything afterwards. Geoff Vallis has a page of classic papers that I find worth looking at, though naturally it's biassed towards his interests: "dynamics" (large-scale flow) rather than "physics" (the rest) or climate. MetSoc have a supposedly similar page but only including papers they published.
Both therefore omit Manabe & Wetherald 1967 which even by those 2 authors' standards has a great deal of physics & is as readable as ever, & Hansen et al. 1984 which introduced the quantification of feedback to our literature.

And here are a few blogs - Isaac Held,
Ed Hawkins,
Angus Ferraro,
Steve Easterbrook &
William Connolley
- & Matt Clark's photostream.

AOPP colleagues may find some useful stuff on computing &c on my old intranet page http://www.atm.ox.ac.uk/user/ingram/ or go straight to my publication list http://www.atm.ox.ac.uk/user/ingram/papers.pdf