Machine learning weather forecasts and black swan events

Leave a reply

Decorative painting of a stormy seascapeA couple of weeks ago I read about Google’s new weather forecasting algorithm, GraphCast.  It takes a radical new approach to forecasting by using machine learning rather than modelling the weather using the laws of physics [see ‘Storm in a computer‘ on November 16th, 2022].  GraphCast uses a graph neural network that has been trained on 39 years (1979 -2017) of historical data from the European Centre for Medium-Range Weather Forecasts (ECMWF). It requires two inputs: the current state of the weather and the state six hours ago; then it predicts the weather six hours ahead with a 0.25 degree latitude-longitude resolution (about 17 miles) at 38 vertical levels.  This compares to ECMWF’s high resolution forecasts which have 0.1 degree resolution (about 7 miles), 137 levels and 1 hour timesteps.  Although the training of the neural network took about four weeks on 32 Cloud TPU v4 devices (Tensor Processing Units), the forecast requires less than a minute on a single device whereas the ECMWF’s high resolution forecast requires a couple of hours on a supercomputer.  Within a day or so of reading about GraphCast, we watched ‘The Day After Tomorrow’, a movie in which a superstorm suddenly plunges the entire northern hemisphere into an ice age with dramatic consequences.  Part of the movie’s message is that humanity’s disregard for the state of the planet could lead to existential consequences.  It occurred to me that the traditional approach to weather forecasting using the laws of physics might predict the onset of such a superstorm and avoid it becoming a black swan event; however, it is very unlikely forecasts based on machine learning would predict it because there is nothing like it in the historical record used to train the neural network.  So for the moment we should continue to use the laws of physics to model and predict the weather since climate change appears to be making superstorms more likely [see ‘More violent storms‘ on March 1st 2017].

Sources:

Blum A, The weather forecast may show AI storms ahead, FT Weekend, 18/19 November 2023.

Lam R, Sanchez-Gonzalez A, Willson M, Wirnsberger P, Fortunato M, Alet F, Ravuri S, Ewalds T, Eaton-Rosen Z, Hu W, Merose A. Learning skillful medium-range global weather forecasting. Science. 10.1126/science.adi2336, 2023.

Image: Painting by Sarah Evans owned by the author.

 

Empathy with the continuing background noise in society

Leave a reply

Image of book cover for 'a flat place' by Noreen MasudResearch has shown that skimming while reading in digital media reduces the inclination and perhaps ability to engage in higher level reading, while a lack of higher-level reading practice compromises the efficacy of skimming when reading. Higher-level reading implies critical and conscious reading, slow reading, non-strategic reading and long-form reading, according to Schuller-Zwierlein et al, 2202.  The psychologist, Steven Pinker has argued that we learn empathy by immersing ourselves in other people’s minds through reading.  During a recent weekend break, I immersed myself in Noreen Masud’s beautiful book, ‘a flat place’.  It is a memoir about childhood trauma, patriarchy and colonialism told through stories associated with flatlands outside Lahore, at Orford Ness, the Cambridgeshire fens, Morecambe Bay and Orkney.  I read it while staying in the flat landscape around Dunham Massey between Warrington and Manchester which made the physical topography described by Masud resonate with me.  However, her reflections on her and our psyche were also deeply significant – she opens one chapter with a quote from Laura S Brown’s article, ‘Not Outside the Range: One Feminist Perspective on Psychic Trauma’, which perhaps is core to her story: ‘…the constant presence and threat of trauma in the lives of girls and woman of all colors, men of color…, lesbian and gay people, people in poverty and people with disabilities has shaped our society, a continuing background noise rather than an unusual event’.

Brown LS. Not outside the range: One feminist perspective on psychic trauma. American Imago. 119-33, 1991.

Masud N, a flat place, Hamish Hamilton, 2023

Schüller-Zwierlein A, Mangen A, Kovač M, van der Weel A. Why higher-level reading is important. First Monday. 27(5) Sep 5, 2022.

Chirping while calculating probabilities

1 Reply

Decorative image of a pink roseA couple of weeks ago, I visited the London headquarters of IBM in the UK and Ireland for discussions about possible areas of collaboration in research and education.  At the end of our meeting, we were taken to see some of their latest developments, one of which was their Quantum System One computer.  We had seen its casing, a shiny silver cylinder about half metre in diameter and a metre and half long with a hemispherical lower end, hanging in a sealed glass cube in the lobby of the building.  The computer we viewed was also suspended from the ceiling of a sealed glass cube in order to isolate it from vibration, but was without its cylindrical cover so that we could see its innards which need to be cooled to cryogenic temperatures.  The room in which it was displayed was darkened and a soundtrack of the computer operating added to the atmosphere – it sounded like birds chirping.  IBM are already operating quantum computers, starting in 2019 with a 27-qubit processor and achieving 433 qubits last year with plans for 4,158+ qubits in 2025 in their roadmap.  There are about 80 companies focussed on quantum computing worldwide, including Universal Quantum who are working on a million qubit computer.  Qubit is short for quantum bit and is the quantum mechanical analogue of a classical computer bit.  A computer bit works in binary and can only have a value of 0 or 1.  Whereas a qubit holds information about the probability amplitudes for 0 and 1 which will always have a sum of 1.  The use of probability amplitudes allows complex systems to be described more efficiently and larger solution spaces to be explored.  IBM’s quantum processors are thin wafers about the same size as the one in your laptop but their need for cryogenic temperatures and vibration isolation means we will not be using them at home any time soon.

Achievements, happiness and the passage of time

Leave a reply

A couple of weeks ago, I wrote about time as ‘a giant wheel rotating through cycles of creation and destruction leading, over aeons, to the birth and death of entire worlds’ [see ‘Aeonian cycles of creation and destruction’ on October 18th, 2023].  I had written previously about Aristotle’s view of time as the measurement of change and how Newton believed that time passes even when nothing changes [see ‘We inhabit time as fish live in water’ on July 24th, 2019].  I recently read ‘The Wall’, a beautiful and thought-provoking, post-apocalyptic novel by Marlen Haushofer, in which the narrator states ‘Time only seemed to be passing quickly.  I think time stands quite still and I move around in it, sometimes slowly and sometimes at a furious rate.’  This aligns with the fish-in-water concept of time rather than the giant revolving wheel.  I recently had a conversation with a colleague about our perception of time as we looked back on our lives which made us feel that time has sped past whereas at the time it appeared to be passing slowly.  Perhaps our familiarity with the past, a landscape through which we have travelled, foreshortens it or is that I might have less than a thousand weeks left [see ‘One just raced past and I have only about 1000 left’ on September 8th, 2021] .  Haushofer’s narrator also says, ‘I had achieved little that I had wanted, and everything I had achieved I had ceased to want’.  In my working life, I have some empathy with this statement, particularly the second part.  I have moved through time at a furious rate, striving towards accomplishments; but now that I have most of them, they seem relatively unimportant.  They are certainly not the key to happiness which can be found anywhere through supporting and valuing others [see ‘A view from the middle’ on March 22nd, 2023] as well as in concentration so intense, for instance though reading or writing, that you lose your sense of time leading to a deep sense of happiness and well-being [see ‘You can only go there in your head’ on May 11th, 2022].  I wrote this post on a Sunday afternoon after spending a couple of hours sitting in the warm October sunshine on the campus of the University of Illinois Urbana Champaign reading ‘Mr President’ by Miguel Angel Asturias – both the reading and writing have left me in a happy state of mind.

Source:

Marlen Haushofer, The Wall, Vintage Classics/Penguin Random House, 2022.