William Ingram

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William Ingram

Academic Visitor

I work for the Met Office Hadley Centre for Climate Science and Services. I spend some of my time in Oxford, some at the MOHC unit in Reading & a bit at MO HQ in Exeter. (My office in Oxford is 118, the last at the front on the 1st floor of the "old" AOPP building before the fire door into the Hooke building: if you come in the front door of that building (the one above ground level) & follow the signs to the Hooke Meeting Room you'll pass it.)

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, but we had no physical explanation for its size. Physically it seemed just as plausible for the effect to be negligible, or so strong that a "run-away" water vapour greenhouse effect was possible (in which case the Earth as we know it could not exist).
I introduced the "partly-Simpsonian" approach to the water vapour feedback - click here to read about it.

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 had been wanting to get done for a couple of decades is described on the "Teaching & supervising" tab (click above - sorry but this system makes it impossible to link to it.)

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".

Here's my publication list.

This is the Met Office's Unified forecast/climate Model, one of the world's leading climate models as well as one of the world's leading weather forecasting models, which the Met Office makes available to the UK academic community. However, this powerful, and in many ways flexible, million-line program is not always user-friendly when first encountered.

There is a vast amount of official documentation, available alongside the code on the NCAS pages:
which (once you can log on) should often be your 1st port of call - but that was written for MO staff working alongside experienced colleagues, & so is likely to be too detailed for someone who has never used the UM.
The "MONSooN" collaboration twiki:
also contains a great deal of potentially useful stuff. (You need to register to get access: bottom of its home page.) In particular, it will allow you to join the met-office.um-collab.um.general newsgroup, where you can post queries that can be read and answered by MO staff. You will also be able to look at the slides from the UM User Tutorial, run at MO HQ in Exeter for a week in early summer, which may be worth your going to.
MONSooN itself is a supercomputer shared between MO & NERC users, very handy for MO colleagues to transfer UM files & code,
so best to apply for an account sooner rather than later.
Even to run the new user interface, Rose, here you need accounts on PUMA, NCAS's system to access the UM, & on MOSRS (email cms-support ncas.ac.uk to get the account, & then follow the set-up instructions at
so you can use it).
The NCAS helpdesk records at
list problems other users have had when running the model, & so may be useful if you have a similar one.
If you're interested in chemistry &/or aerosols, I'm told Luke Abraham's tutorial for UKCA (the Met Office / NERC joint chemistry-aerosol global atmospheric model) is good.
I was going to link to some much more accessible descriptions of what such a model basically is & so what it can & cannot do, & what are the particular features of this one - but I haven't yet found any, so any suggestions very welcome!

The UM is in some ways more a modelling framework than a single model. The MO itself has at times had major differences between its operational forecast models & benchmark climate models, and "standard" climate models of different generations co-exist. There are vast number of pre-supplied options you could change, & you can make any changes you want to the code. But of course in practice most users use standard configurations, or standard configurations plus a particular change they are interested in.

Feel free to ask me about the UM, but please be realistic! The sooner you ask me about something the sooner you can hope to get things sorted - & things may well be more complex or administratively slow than you expected. (The Met Office, as you'd expect for the Civil Service, plans ahead & follows its plans, & has more complex approval procedures than are typical here - please don't ask for a computer account, say, let alone a letter of support, at the last minute.)
It's often best to talk face-to-face to start with. Thursday is the day I am most often in Oxford but it is often busy - if you email me we can try to arrange to meet.

I'm a scientist, not a programmer. Please do ask questions like "My UM run crashes with this error message - can you suggest why?", but if you want to install the UM on an Oxford machine, UM_collaboration@metoffice.gov.uk will be far more use than I could be.

More generally, do feel free to ask me about any non-UM MO matters - as long as you are prepared for me to say "Sorry, but I don't know"!
(One area in particular that people might be interested in is the MO's climate datasets, which are documented & available at
though I understand this is being updated.)

Similarly I can't advise on the range of software packages used for visualization and/or analysis of atmospheric, oceanic, &c simulation - xconv, nco, panoply, iris, cfpython, GrADS, vapor, the ukmo IDL library, VERDI, thea... because, like most people, I tend to stick to what I know works for me, but I'd like to provide a list of what there is and what each can do - or, better still, link to somewhere that already has all that, if anyone knows of anywhere?

Please always remember that the UM is not in the public domain - it is Met Office intellectual property and extremely valuable to them. We are licenced to use it for research purposes, but cannot pass it on to anyone who does not have a licence, or put it on a website or ftp site where anyone could access it. Our licence requires us to tell the Met Office the results of our research with their model, so do do so if it might be of interest or use to them - feel free to ask me who.

This year (2018-9) I'm teaching the 4th-year atmospheric & oceanic physics option C5 again, normally at 3:30-5 Thursday afternoon in the Barnett Room. For full listing of class times and places see
http://eodg.atm.ox.ac.uk/user/dudhia/teaching/c5_schedule.html &

I have mild face-blindness/prosopagnosia. If I still struggle to recognize you even in class at the end of the academic year, I've probably been trying harder than you ever have.

I also supervise research students when in Oxford - currently only one, Thomas Hornigold.

Before him I co-supervised Richard Millar, who after a couple of years more left Oxford to work for the statutory Committee on Climate Change. He is interested in how the insights from the latest climate science can be successfully embedded in effective climate policy. His research spans the physical and economic consequences of climate policy and aims to investigate robust pathways to achieving global climate goals of net-zero emissions. In his time at Oxford he lead-authored A modified impulse-response representation of the global near-surface air temperature and atmospheric concentration response to carbon dioxide emissions, Model structure in observational constraints on transient climate response, Principles to guide investment towards a stable climate, The utility of the historical record for assessing the transient climate response to cumulative emissions, and Emission budgets and pathways consistent with limiting warming to 1.5 degrees C, as well as contributing to 6 peer-reviewed papers and several Oxford Martin School briefing papers.

Before him, Adam Levy worked on a project I had been wanting to do for a couple of decades:
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.
So Adam worked 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 we hope quantifying "doing the wrong thing" v "doing the right thing but in the wrong place" will 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 hoped that in both these cases it will bring the GCMs together. This would make the results more consistent and physically-based, so reducing uncertainty for the future, and increasing potential to detect past changes in observations.
See his proof-of-concept paper, his methods paper, and his detection & attribution paper for more.

If I don't seem to be what you expected you may want Will Ingram at Exeter (the University, not the College).

My 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 should take more advantage of it - particularly its meetings, listed at:

Other relevant seminar series near Oxford are ECMWF's, Reading Met's "departmental seminars" and less formal "lunchtime seminars", and
Imperial's seminars.

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. If you just want a basic summary, there's the Royal Society's "Climate change: evidence and causes".

Here is what I think is a good summary of how to write good scientific English, & Mike McIntyre's summary of how & why to be lucid

Here is Raymond Hide's RMS Presidential Address on "Motions in planetary atmospheres".

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.

AOPP colleagues may find some useful stuff on computing &c on my old intranet page http://www.atm.ox.ac.uk/user/ingram/

My publication list is here.

And here are a few blogs - Isaac Held,
Ed Hawkins,
Rob Wood's clouds,
Angus Ferraro,
Kate Marvell,
Met Office news,
Reading Met,
Steve Easterbrook &
William Connolley
- & the Cloud Appreciation Society's Cloud of the Month
& Matt Clark's photostream.

(If any links on this page seem to be out of date, please tell me!)