Forecasting space weather using “similar day” approach

Carl Haines – carl.haines@pgr.reading.ac.uk

Space weather is a natural threat that requires good quality forecasting with as much lead time as possible. In this post I outline the simple and understandable analogue ensemble (AnEn) or “similar day” approach to forecasting. I focus mainly on exploring the method itself and, although this work forecasts space weather through a timeseries of ground level observations, AnEn can be applied to many prediction tasks, particularly time series with strong auto-correlation. AnEn has previously been used to predict wind speed [1], temperature [1] and solar wind [2]. The code for AnEn is available at https://github.com/Carl-Haines/AnalogueEnsemble should you wish to try out the method for you own application. 

The idea behind AnEn is to take a set of recent observations, look back in a historic dataset for analogous periods, then take what happened following those analogous periods as the forecast. If multiple analogous periods are used, then an ensemble of forecasts can be created giving a distribution of possible outcomes with probabilistic information. 

Figure 1 – An example of AnEn applied to a space weather event with forecast time t0. The black line shows the observations, the grey line shows the ensemble members, the red line shows the median of the ensemble and the yellow and green lines are reference forecasts. 

Figure 1 is an example of a forecast made using the AnEn method where the forecast is made at t0. The 24-hours of observations (black) prior to tare matched to similar periods in the historic dataset (grey). Here I have chosen to give the most recent observations the most weighting as they hold the most relevant information. The grey analogue lines then flow on after t0 forming the forecast. Combined, these form an ensemble and the median of these is shown in red. The forecast can be chosen to be the median (or any percentile) of the ensemble or a probability of an event occurring can be given by counting how many of the ensemble member do/don’t experience the event.  

Figure 1 also shows two reference forecasts, namely 27-day recurrence and climatology, as benchmarks to beat. 27-day recurrence uses the observation from 27-days ago as the forecast for today. This is reasonable because the Sun rotates every 27-days as seen from earth so broadly speaking the same part of the Sun is emitting the relevant solar wind on timescales larger than 27-days. 

To quantify how well AnEn works as a forecast I ran the forecast on the entire dataset by repeatedly changing the forecast time t0 and applied two metrics, namely mean absolute error (MAE) and skill, to the median of the ensemble members. MAE is the size of the mean difference between the forecast made by AnEn and what was actually observed. The mean of the absolute errors over all the forecasts (taken as median of the ensemble) is taken and we end up with a value for each lead time. Figure 2 shows the MAE for AnEn median and the reference forecasts. We see that AnEn has the smallest (best) MAE at short lead times and outperforms the reference forecasts for all lead times up to a week. 

Figure 2 – The mean absolute error of the AnEn median and reference forecasts.

An error metric such as MAE cannot take into account that certain conditions are inherently more difficult to forecast such as storm times. For this we can use a skill metric defined by  

{\text{Skill} = 1 - \frac{\text{Forecast error}}{\text{Reference error}}}

where in this case we use climatology as the reference forecast. Skill can take any value between -\infty and 1 where a perfect forecast would receive a value of 1 and an unskilful forecast would receive a value of 0. A negative value of skill signifies that the forecast is worse than the reference forecast. 

Figure 3 shows the skill of AnEn and 27-day recurrence with respect to climatology. We see that AnEn is most skilful for short lead times and outperforms 27-day recurrence for all lead times considered.  

Figure 3 – The skill of the AnEn median and 27-day recurrence with respect to climatology.

In summary, the analogue ensemble forecast method matches current conditions with historical events and lifts the previously seen timeseries as the prediction. AnEn seems to perform well for this application and outperforms the reference forecasts of climatology and 27-day recurrence. The code for AnEn is available at https://github.com/Carl-Haines/AnalogueEnsemble

The work presented here makes up a part of a paper that is under review in the journal of Space Weather. 

Here, AnEn has been applied to a dataset from the space weather domain. If you would like to find out more about space weather then take a look at these previous blog posts from Shannon Jones (https://socialmetwork.blog/2018/04/13/the-solar-stormwatch-citizen-science-project/) and I (https://socialmetwork.blog/2019/11/15/the-variation-of-geomagnetic-storm-duration-with-intensity/). 

[1] Delle Monache, L., Eckel, F. A., Rife, D. L., Nagarajan, B., & Searight, K.(2013) Probabilistic Weather Prediction with an Analog Ensemble. doi: 10.1175/mwr-d-12-00281.1 

[2] Owens, M. J., Riley, P., & Horbury, T. S. (2017a). Probabilistic Solar Wind and Ge-704omagnetic Forecasting Using an Analogue Ensemble or “Similar Day” Approach. doi: 10.1007/s11207-017-1090-7 

Why renewables are difficult

Adriaan Hilbers – PhD researcher at Imperial and Reading a.hilbers17@imperial.ac.uk

Adapted from a 2018 blog post: see the original here

Renewable energy represents one of the most promising solutions to climate change since it emits no greenhouse gases. However, it poses some difficulties for power systems. Source: U. Leone

The public have been aware of the importance of reducing carbon emissions since around the 1980’s. Furthermore, renewable technologies such as solar and wind have been around for decades. Under these conditions, it’s surprising that most countries still generate the majority of their electricity from carbon-emitting fossil fuels. Why, after decades of both the problem and a possible solution being known, haven’t renewables taken off yet? This article describes why renewables are “difficult”, and how the world can keep the lights on into the future in a cheap, secure, and sustainable way. 

Until recently, the primary reason was economics. It was impossible to build wind turbines and solar panels cheaply enough to compete with fossil fuel technologies, which have become highly cost effective after more than 100 years of use. Governments were not willing to spend billions to subsidise renewables when electricity could be generated cheaply by other means. Recently, however, improved manufacturing methods, economies of scale and increased competition sent prices plummeting. The price of solar panels has decreased by a factor of 200 in the last 45 years, and wind farms (even offshore) are now cost-effective without subsidy.  

So, is it just a matter of time before fossil fuel electricity disappears? Why are societies still so hesitant to go 100% renewable? To understand why, one needs a quick introduction to power systems: the industries, infrastructures and markets based around electricity. 

At their core, power systems are supply & demand problems. Industries and consumers use electricity provided by generators. One key feature distinguishes power systems from other economic markets: there is very limited means of storing it at large scale (with the notable exception of hydropower, discussed below). For this reason, supply must match demand on a second-by-second basis. 

A still from Drax Electric Insights, where electricity demand and generation levels can be browsed through, both in real time and historically. Source: Drax Electric Insights

(As an aside, in the UK, there is a fantastic website, called Drax Electric Insights, in which the total UK electricity demand, and exactly from which sources it is being generated, can be browsed through in real time as well as historically. Looking through it for a few minutes will give a better feel for how power systems work than any blog post can). 

Before renewables, most electricity came from fossil fuel plants. Fuel (mostly coal or gas) was burnt at different rates and level of electricity supply was directly adjusted to meet demand. This isn’t always easy; for example, the UK’s system operator had to deal with a massive demand spike just after the royal wedding, as millions turned on their kettles at the same time.  

A famous graph showing total UK electricity demand during the 1990 World Cup semi-final against Germany, with spikes at times that viewers turned on their kettles en masse. System operators had to rapidly adjust supply to ensure the lights stayed on. Source: National Grid

With renewables, the single biggest difficulty is that their production levels can’t be controlled. It’s not always windy or sunny, and times of high renewable output do not always align with times of high demand. How does one ensure the lights stay on on a cloudy day or when the wind tails off? 

In most countries, this is not yet a problem since renewable capacity is still small and there’s ample conventional backup capacity. Renewables produce whatever electricity they can, and the rest is picked up by the conventional plants.  

A problem occurs when countries start generating most of their electricity from renewables as this drastically changes the economic outlook of power markets. In a nutshell, building renewable capacity displaces fossil fuel generation, but not generation capacity; all power plants must be kept open for the rare days when there isn’t any wind or sun. Keeping these plants open but using them infrequently is very expensive, and closing them is impossible, unless you want to accept significant risks of blackouts on calm, cloudy days. It’s a perilous choice: higher electricity prices or reduced security of supply, and this problem defines the difficulties of renewable electricity systems. 

Thankfully, there are a few ways that society can generate most of their electricity from renewables while keeping prices low and supply secure. They fall broadly into two categories. 

The first is electricity storage. With grid-scale storage, excess electricity production on windy or sunny days can be stored and used in times when renewable output is low. Besides adding to supply security, this would enhance the economic picture since storage owners buy up electricity when price is low and sell it when price is high, evening out price jumps and allowing a smaller number of conventional plants to run more often. Almost all grid-scale storage currently in existence is hydropower, which countries like Norway use to generate almost all their electricity but requires a mountainous terrain and access to water. The reason other grid-scale storage is rare is economics. Most storage technology (e.g. battery) prices still have to drop significantly before they can be used at large scale. 

Hydropower provides an economical option to store electricity, but requires mountainous terrain. Source: skeeze

A second solution is interconnecting different countries and allowing them to share electricity. When it is wind-free in London, it usually is in Scotland as well, bit it may be windy in Germany or Spain. Transporting electricity around could help alleviate supply insecurity. Many countries are doing just this; the UK, for example, currently has interconnections with France, the Netherlands, Belgium and Ireland, and more are in the pipeline. They may eventually from part of the European Supergrid, where electricity can be transported across Europe to balance out regional renewable supply peaks and troughs. 

The prospect of combining hydropower and interconnections between countries is tempting, since it means countries with lots of wind but little storage capacity, like Germany or Denmark, could “use Norway as a battery” by exporting their excess wind power to Norway in windy periods, which allows dams to accumulate water. In calm spells, hydropower generation levels are increased and excess electricity exported back the other way. Making this work will require significant increases in Norwegian hydropower infrastructure, interconnection lines and international cooperation. 

The batteries in electric cars can be used for grid management provided that owners agree to this. Source: Marilyn Murphy

Another creative solution to the storage problem is to use the batteries in electric cars. Electric car uptake will lead to demand spikes when people return from work and plug them in. An electric car owner can get the option of cheaper electricity if it means her car’s battery is not charged (smart charging), or even emptied (known as vehicle-to-grid), during demand spikes and recharged when demand is lower. Such approaches are currently being trialled in the UK

Current power systems are not yet ready to use renewables for the majority of their electricity supply. However, the immediacy of the climate change danger means business-as-usual is not an option, and a total energy revolution is required. Presently, the most realistic solution is the use of renewables (see a separate blog post on nuclear power here). Nobody knows exactly how the power system of the future will look. But everyone agrees it will be very different. 

A still from an online tutorial on power system models, showing generation from different sources.

Want to know more? For a similar discussion on the merits of nuclear power, see this blog post. To get a feel for how a power system works, see this page. It allows users, inside a cloud (no downloads or installs necessary), to create their own power system for the United Kingdom, and see how electricity is generated from renewable and conventional sources. 

Note: this article was adapted from a 2018 blog post: see the original here

The Greatest Storm – A Virtual Pantomime

Devon Francis d.francis@pgr.reading.ac.uk
Max Coleman m.r.coleman@pgr.reading.ac.uk

Every year the Met-PhDs put on a Christmas pantomime and perform it to the rest of the department. The autumn term always seems to drag: the mornings are dark; the evenings are darker; and no matter how hard you try, the term just feels so busy! So what better way to finish off the term than with department jokes, terrible singing and unnecessary Benny Hill chase scenes?

Met Panto 2020 virtual group photo

And despite of a global pandemic that is in full swing, this year would be no different – the show must go on! On 10th December we premiered the very first virtual Met panto: The Greatest Storm! – A spin-off of the 2017 film ‘The Greatest Showman’. The Greatest Storm follows Professor Sue Gray Barnum (or PG Barnum for short) on her journey to find the greatest storm. On her way she meets her “misfit” team: Helen Dacre, Pete Inness, Tom Frame and Javier Amezcua, and recruits her right-hand man: Philip-Craig Carlyle. Together they develop a new instrument: DOROTHY, the Data recORding unit fOr in-siTu sting jet measurements High in the skY. But with COVID lurking around every corner, will they ever be able to measure the Greatest Storm? (…although it will actually just be the greatest storm on record…)

Panto 2020 poster – designed and created by Meg Stretton

This year, Max and I were persuaded volunteered for the role of panto organisers, with the promise that running the panto would be ‘much easier’ than previous years as everything would be online. This was partly true, though there was still a lot of last-minute tweaking…

We were very fortunate that Kris Boykin brought forward the idea to recreate The Greatest Showman, with a detailed plan for the plot, which fought off the other (very good) competition for plot ideas. This made the script writing relatively pain-free as we filled in the details and decided on which of the staff should be included.

Next was the song writing: in retrospect, the songs we chose were quite difficult to get right, as it was challenging to stay in time when singing for most of them, especially when we had changed the lyrics to include meteorological puns! In a live panto this might not have been so bad, but as everything had to be recorded individually and put together by our audio editing experts Dominic Jones and Beth Saunders, we can only say, Dom, we’re very sorry…  

The next 9 weeks were filled with read throughs, character selection and filming. In a normal year, these weeks would be relatively relaxed, with rehearsals spanning the full 9 weeks, however as we were aware that the video editors Lauren James and Wilson Chan had a lot of work to do in putting all of the scenes together, we tried to film as early as possible to give them more time. Our initial plan was to meet up on a weekend to film the parts in a socially distanced setting, but as the second lockdown was announced, we had to quickly change our plan. Some scenes were filmed individually, but the majority were filmed over Zoom: although this had reduced camera quality, it was much more fun to see each other every week and laugh at everyone’s wacky costumes and improvisation!

The last week leading up to Thursday’s showing (tomorrow as we’re writing this!) was slightly busier, with reviewing footage and making final edits, in the knowledge that in these unprecedented circumstances most of the cast will not have seen a complete run through before the final showing! In the end it all came together with an entirely smooth and seamless virtual viewing experience / it all went horribly wrong and we should never have been entrusted with panto (delete as applicable), which everyone viewing hopefully enjoyed!

Screenshot of scene 2 – the misfits’ entrance.

With that, we’d like to say thank you so much to everyone involved, from script writers, band, editors, cast and everyone that helped both on and off our virtual stage! It has been so lovely to see everyone come together, and although has been a very tiring process, panto 2020 has been a very welcome distraction to the rest of 2020!

This year we did not sell tickets, but instead asked for donations to cover our (reasonably small!) running costs, plus any extra will go to the Reading Meteorology department’s charity: San Francisco Libre Association. If you didn’t donate on the night, but wanted to, here’s a link to our donations page – https://paypal.me/pools/c/8uIzsVEQwB. We were so humbled by everyone that has already donated, both small and large amounts, we really appreciate it!

Thank you to everyone that watched The Greatest Storm on Thursday, we hope you had a fun evening! And we look forward to next year’s panto; who will be next to volunteer for this incredible tradition, with panto 2021…?

The Social Metwork in 2020

James Fallon – j.fallon@pgr.reading.ac.uk
Brian Lo – brian.lo@pgr.reading.ac.uk 

Hello dear readers! Reviewing submissions and discovering the fascinating research that takes place in Reading Meteorology has been an amazing experience, and a personal highlight of the year!

Thank you to everyone who has contributed to the social metwork this year, and especially to those who have been patient whilst myself and Brian have been getting used to our new roles as co-editors. The quality of submissions has been very high, but don’t let that deter you if you haven’t written for the blog before! Writing for the social metwork is not as tricky as you might think – we promise!

At the time of writing, the blog has had over 5550 visitors, and is on track for an all time high by the end of the year. We hope that the social metwork has contributed to lifting spirits and continuing the met department social atmosphere throughout the year. In case you missed any posts, or want a second look at some, here is a list of all the posts from this year:

January
North American weather regimes and the stratospheric polar vortex – Simon Lee
Evaluating ocean eddies in coupled climate simulations on a global scale – Sophia Moreton
The (real) butterfly effect: the impact of resolving the mesoscale range – Tsz Yan Leung

February
Life on Industrial Placement – Holly Turner
An inter-comparison of Arctic synoptic scale storms between four global reanalysis datasets – Alec Vessey
A new, explicit thunderstorm electrification scheme for the Met Office Unified Model – Ben Courtier

March
Relationships in errors between meteorological forecasts and air quality forecasts – Kaja Milczewska
Tips for working from home as a PhD student – Simon Lee

May
Air pollution and COVID-19: is ozone an undercover criminal? – Kaja Milczewska
The philosophy of climate science – Mark Prosser
Explaining complicated things with simple words: Simple writer challenge – Linda Toča

June
Methane’s Shortwave Radiative Forcing – Rachael Byrom

July
How do ocean and atmospheric heat transports affect sea-ice extent? – Jake Aylmer

August
A Journey through Hot British Summers – Simon Lee
Exploring the impact of variable floe size on the Arctic sea ice – Adam Bateson

September
How Important are Post-Tropical Cyclones to European Windstorm Risk? – Elliott Sainsbury
The Scandinavia-Greenland Pattern: something to look out for this winter – Simon Lee

October
My journey to Reading: Going from application to newly minted SCENARIO PhD student – George Gunn
The visual complexity of coronal mass ejections follows the solar cycle – Shannon Jones
Organising a virtual conference – Gwyneth Matthews
Visiting Scientist Week Preview: Laure Zanna – Kaja Milczewska

November
Demonstrating as a PhD student in unprecedented times – Brian Lo
ECMWF/EUMETSAT NWP SAF Workshop on the treatment of random and systematic errors in satellite data assimilation for NWP – Devon Francis
Extra conference funding: how to apply and where to look – Shannon Jones
Youth voices pick up the slack: MOCK COP 26 – James Fallon

Enjoy the panto, have a very merry Christmas, and here’s to 2021!
From your metwork co-editors James & Brian!

Youth voices pick up the slack: MOCK COP 26

James Fallon – j.fallon@pgr.reading.ac.uk

This year’s Conference of the Parties (COP) should have taken place earlier in November, hosted by the UK in Glasgow and in partnership with Italy. Despite many global events successfully moving online this year, from film festivals to large conferences such as the EGU general assembly, the international climate talks were postponed until November 2021.

But young people around the world are more engaged than ever before with the urgent need for international cooperation in the face of the climate emergency. The Fridays for Future (FFF) movement has recorded participation since late 2018 of more than 13,000,000 young people, in 7500 cities from all continents. FFF has adapted to the covid-19 crisis, and on 25th September this year participants from over 150 countries took part both online and in the streets, highlighting the Most Affected People and Areas (MAPA).

Unimpressed by the delay of important climate talks and negotiations, students and youth activists from FFF and a multitude of groups and movements have initiated the MOCK COP26, a 2-week online global conference on climate change that mirrors the real COP.

“My country, the Philippines, is struggling. We don’t want more floods that rise up to 15 feet, winds that peel off roofs in seconds, the rain that drowns our pets and livestock, and storm surges that ravage coastal communities. We don’t want more people to die. We’re still a developing country that contributes so little to global carbon emissions yet we face the worst of its consequences. This is absurd! 

Angelo, Philippines
https://www.mockcop.org/why

Programme

Organisers have chosen five themes to focus on:

  1. Climate education
  2. Climate justice
  3. Climate resilient livelihoods
  4. Health and wellbeing
  5. Nationally Determined Contributions

Full programme here: https://www.mockcop.org/programme

Over a dozen academic support videos break down complicated topics such as “The Kyoto Protocol”, “Agriculture and Agribusiness”, and the “History of Climate Negotiation”. These videos are helping youth delegates and all participants to understand what happens at a COP summit.

Panel sessions have featured United Nations Youth Envoy Jayathma Wickramanayake, 9 year old Climate & Environmental Activist Licypriya Kangujam, and (actual) COP26 president Alok Sharma.

High Level Country Statements

A unique aspect of MOCK COP that I have been excitedly anticipating is the high level country statements; each a 3 minute speech given by youth climate activists representing their nation.

Mock COP26 is not dominated by big polluters as COP26 is. We believe that we need to amplify the people on the frontlines of climate change, which is why we will be aiming to, throughout Mock COP, uplift the voices of those from MAPA (Most Affected People and Areas) countries above those from the Global North. This is why Mock COP26 is special.

Jamie Burrell, UK
https://www.mockcop.org/today

Youth delegates have been encouraged to give speeches in whichever language they are most comfortable talking. At the time of writing, subtitles don’t appear to be fully functioning. However a large number of talks are given in English, and transcripts of all talks have been made available here: https://drive.google.com/drive/folders/1wnQUMt-rcD9XoKtg8YPWba_LZSf16qTD

I highly recommend setting some time aside to give these speeches a listen. Although the total number might put you off, it is very easy to jump in and out of talks. You can find videos embedded below, or on the official youtube channel.

Africa

Pick: Two youth delegates represent Morocco. Whilst Morocco has been ranked a role model for climate action, the reality of the country’s future is alarming. Globally the most affected are the least protected. It’s time for world leaders to protect everyone.

Americas

Pick: The delegate for Suriname explains risks faced as a Small Island Developing State (SIDS) with infrastructure near the coast. Suriname must implement climate adaptation whilst enhancing its legislation in forestry, mining, and agriculture.

Asia

Pick: Indonesia’s delegate opens with the stark warning that the country will lose 1500 of its islands due to rising sea levels by 2050. The high level statement includes calls to incorporate climate education into the national curriculum, and find ways to protect natural habitat. Indonesia has the 2nd biggest rainforest in the world, but currently has no agreed emissions reductions pathway.

Europe

Pick: Ireland’s youth delegates present a necessarily progressive 5 year plan to stick to the EU target of reducing emissions by at least 65% by 2030. The need for much stronger climate education, and providing access to affordable and sustainable energy, are among many other commitments.

Oceania

Pick: The year started with forest fires devastating large swathes of Australia’s natural habitats. Youth delegates want their nation to lead the world as a renewable energy exporter, and an overhaul of media rules to foster new diverse media outlets and prevent monopolies that currently stall climate action.

What is the hoped outcome?

With so many connected issues relating to the climate and ecological emergency, previous COPs have often seen negotiations stall and agreements postponed. The complexity of tackling this crisis is compounded by the vested interests of powerful governments and coal, oil, and gas profiteers.

But youth messages can be heard loud and clear at MOCK COP 26, reflecting the 5 themes of the conference.

We demand concrete action, not mere promises. It’s time for our leaders to wake up, prioritize the realization of the Green Deal, and cut carbon emissions. 

We won’t have more time to alter the effects of the climate crisis if we let this opportunity pass. The clock is ticking. The time for action is NOW. 

In the wake of covid-19 induced economic shocks, policy makers must ensure genuine green recovery that engages with ideas of global climate justice.

Youth delegate panels will continue over the weekend, working towards the creation of a final statement outlining their demands for world leaders. This will be presented to High Level Climate Action Champion for COP26 Nigel Topping, at the closing ceremony (12:00 GMT Tuesday 1st December)

Extra conference funding: how to apply and where to look

Shannon Jones – s.jones2@pgr.reading.ac.uk

The current PhD travel budget of £2000 doesn’t go far, especially if you have your eye on attending the AGU Fall Meeting in San Francisco. If the world ever goes back to normal (and fingers crossed it will – though hopefully with more greener travel options, and remote participation in shorter conferences?) you might wonder how you are ever going to afford the conferences your supervisors suggest. Luckily, there are many ways you can supplement your budget. Receiving travel grants not only means more conferences (and more travel!), but it also looks great on your CV. In this blog post I share what I have learnt about applying for conference grants and list the main places to apply.

Sources of funding include…

Graduate School Travel Support Scheme

  • Open to 2nd and 3rd year PhD students at the university (or equivalent year if part-time) 
  • 1 payment per student of up to £200 
  • Usually 3 deadlines throughout the year 

There are two schemes open to all PhD students who are members of the IOP (any PhD student who has a degree in physics or a related subject can apply to become a member)

Research Student Conference Fund

  • Unlimited payments until you have received £300 in total
  • 4 deadlines throughout the year: 1st March, 1st June, 1st September and 1st December 
  • Note: you apply for funding from an IOP group, and the conference must be relevant to the group. For example, most meteorology PhD students would apply for conference funding from the Environmental Physics group. You get to choose which groups to join when you become an IOP member. 

CR Barber Trust

  • 1 payment per student of £100-£300 for an international conference depending on the conference location 
  • Apply anytime as long as there is more than a month before the proposed conference 

Legacies Fund

Conference/Meeting Travel Subsistence

From the conference organiser

  • Finally, many conferences offer their own student support, so it’s always worth checking the conference website to see 
  • Both EGU and AGU offer grants to attend their meetings each year 

Application Tips

Apply early!!!

Many of these schemes take months to let you know whether you have been successful. Becoming a member can also take a while, especially when societies only approve new members at certain times of the year. So, it’s good to talk to your supervisor and make a conference plan early on in your PhD, so you know when to apply. 

Writing your application

Generally, these organisations are keen to give away their funds, you just have to write a good enough application. Keep it simple and short: remember the person reading the application is very unlikely to be an expert in your research. It can be helpful to ask someone who isn’t a scientist (or doesn’t know your work well) to read it and highlight anything that doesn’t make sense to them. 

Estimating your conference expenses

You are usually expected to provide a breakdown of the conference costs with every application. The main costs to account for are: 

  • Accommodation: for non-UK stays must apply for a quote through the university travel agent 
  • Travel: UK train tickets over £100 and all international travel must be booked by university too 
  • Subsistence: i.e. food! University rules used to say this could be a maximum of £30 per day – check current guidelines 
  • Conference Fees: the conference website will usually list this 

The total cost will depend on where the conference is. You are generally expected to choose cheaper options, but there is some flexibility. As a rough guide: a 4-day conference within the UK cost me around £400 (in 2019) and a 5-night stay in San Francisco to attend AGU cost me around £2200 (in 2019).  

Reading PhD students at Union Square, San Francisco for AGU! 

Good luck! Feel free to drop me an email at s.jones2@pgr.reading.ac.uk if you have any questions 😊 

ECMWF/EUMETSAT NWP SAF Workshop on the treatment of random and systematic errors in satellite data assimilation for NWP

Devon Francis – d.francis@pgr.reading.ac.uk

The ECMWF/EUMETSAT NWP SAF Workshop (European Centre for Medium-Range Weather Forecasts/European Organisation for the Exploitation of Meteorological Satellites Numerical Weather Prediction Satellite Application Facilities Workshop) was originally to be held at the ECMWF centre in Reading, but as with everything else in 2020 was moved online. The workshop was designed to be a place to share new ideas and theories for dealing with errors in satellite data assimilation: encompassing the treatment of random errors; biases in observations; and biases in the model.

Group photo of attendees of ECMWF/EUMETSAT NWP SAT Workshop – Virtual Event: ECMWF/EUMETSAT NWP SAF Workshop on the treatment of random and systematic errors in satellite data assimilation for NWP.

It was held over four days: consisting of oral and poster presentations; panel discussions; and concluded on the final day with the participants split into groups to discuss what methods are currently in use and what needs to be addressed in the future.

Oral Presentations

The oral presentations were split into four sessions: scene setting talks; estimating uncertainty; correction of model and observation biases; and observation errors. The talks were held over Zoom for the main presenters and shown via a live broadcast on the workshop website. This worked well as the audience could only see the individual presenter and their slides, without having the usual worry of checking that mics and videos were off for other people in the call!

Scene Setting Talks

I found the scene setting talks by Niels Bormann (ECMWF) and Dick Dee (Joint Center for Satellite Data Assimilation – JCSDA) very useful as they gave overviews of observation errors and biases respectively: both explaining the current methods as well as the evolution of different methods over the years. Both Niels and Dick are prominent names amongst data assimilation literature, so it was interesting to hear explanations of the underlying theories from the experts in the field before moving onto the more focused talks later in the day.

Correction of Model and Observation Biases

The session about the correction of model and observation biases, was of particular interest to me as it discussed many new theoretical methods for disentangling model and observation biases which are beginning to be used in operational NWP.

The first talk by Patrick Laloyaux (ECMWF) was titled Estimation of Model Biases and Importance of Scale Separation and looked at weak-constraint 4D-Var: a variational bias correction technique that includes an error term in the model, such that solving the cost function involves varying three variables: the state; the observation bias correction coefficient; and the model error. When the background and model errors have different spatial scales and when there are sufficient reference observations, it has been shown in a simplified model that weak-constraint 4D-Var can accurately correct model and initial state errors. They argue that the background error covariance matrix contains small spatial scales, and the model error covariance matrix contains large spatial scales, which means that the errors can be disentangled in the system. However, without this scale difference, separating the errors would be much harder, so this method can only be considered when there are vast differences within the spatial scales.

On the other hand, the talk by Mark Buehner (Environment and Climate Change Canada) discussed an offline technique that performs 3D-Var analysis every six hours using only unbiased, also known as “anchor”, observations to reduce the effects of model bias. These analyses can then be used as reference states in the main 4D-EnVar assimilation cycle to estimate the bias in the radiance observations. This method was much discussed over the course of the workshop, as it is yet to be used operationally and was very interesting to see a completely different bias correction technique to tackle the problem of disentangling model and observation biases.  

Posters

Poster presentations were shown via individual pages on the workshop website, with a comments section for small questions and virtual rooms – where presenters were available for a set two hours over the week. There were 12 poster presentations available, ranging from the theoretical statistics behind errors as well as operational techniques to tackle these errors.

My poster, focused on figures 1 and 2 which show the scalar state analysis error variances when (1) we vary the state background error variance accuracy for (a) underestimating and (b) overestimating the bias background error variance; (2) we vary the bias background error variance accuracy for (a) underestimating and (b) overestimating the state background error variance.

I presented a poster on work that I had been focussing on for the past few months titled Sensitivity of VarBC to the misspecification of background error covariances. My work focused on the effects of wrongly specifying the state and bias background error covariances on the analysis error covariances for the state and the bias. This was the first poster that I had ever presented so was a fast learning curve in how to clearly present detailed work in an aesthetic way. It was a useful experience as it gave me a hard deadline to conclude my current work and I had to really think about my next steps as well as why my work was important. Presenting online was a very different experience to presenting in person as it involved a lot of waiting around in a virtual room by myself, but when people did come, I was able to have some useful conversations, as well as the added bonus of being able to share my screen to share relevant papers.

Working Groups

On the final day we split ourselves into four working groups to discuss two different topics: the treatment of biases and the treatment of observation errors. The goal was to discuss current methods, as well as what we thought needed to be researched in the future or potential challenges that we would come across. This was hosted via the BlueJeans app, which provided a good space to talk as well as share screens and had the useful option to choose the ratio of viewing people’s videos, to viewing the presenter’s screen. Although I wasn’t able to contribute much, this was a really interesting day as I was able to listen to views of the experts in the field and listen to their discussions on what they believed to be the most important current issues, such as increasing discussion between data centres receiving the data and numerical weather prediction centres assimilating the data; and disentangling biases from different sources. Unfortunately for me, some of them felt that we were focussing too much on the theoretical statistics behind NWP and not enough on the operational testing, but I guess that’s experimentalists for you!

Final Thoughts

Although I was exhausted by the end of the week, the ECMWF/EUMETSAT NWP SAF Workshop was a great experience and I would love to attend next time, regardless of whether it is virtual or in person. As much as I missed the opportunity to talk to people face to face, the organisers did a wonderful job of presenting the workshop online and there were many opportunities to talk to the presenters. There were also some benefits of the virtual workshop: people from across the globe could easily join; the presentations were recorded, so can easily be re-watched (all oral and poster presentations can be found via this link – https://events.ecmwf.int/event/170/overview); and resource sharing was easy via screen sharing. I wonder whether future workshops and conferences could be a mixture of online as well as in person, in order to get the best of both worlds? I would absolutely recommend this workshop, both for people who are just starting out in DA as well as for researchers with years of experience, as it encompassed presentations from big names who have been working in error estimation for many years as well as new presenters and new ideas from worldwide speakers.

Demonstrating as a PhD student in unprecedented times

Brian Lo – brian.lo@pgr.reading.ac.uk 

Just over a month ago in September 2020, I started my journey as a PhD student. Since then, have I spent all of my working hours solely on research – plotting radar scans of heavy rainfall events and coding up algorithms to analyse the evolution of convective cells?  Surely not! Outside my research work, I have also taken on the role of demonstrating this academic year. 

What is demonstrating? In the department, PhD students can sign up to facilitate the running of tutorials and problems, synoptic, instrument, and computing laboratory classes. Equipped with a background in Physics and having taken modules as an MSc student at the department in the previous academic year, I signed up to run problem classes for this year’s Atmospheric Physics MSc module. 

I have observed quite a few lectures during my undergraduate education at Cambridge, MSc programme at Reading and also a few Massive Open Online Courses (MOOCs) as a student. Each had their unique mode of teaching. At Cambridge, equations were often presented on a physical blackboard in lectures, with problem sheet questions handed in 24 hours before each weekly one-hour “supervision” session as formative assessment. At Reading, there have been less students in each lecture, accompanied by problem classes that are longer and more relaxed, allowing for more informal discussion on problem sheet questions between students. These different forms of teaching were engaging to me in their own ways. I have also given a mix of good and not-as-good tutorial sessions for Year 7s to 13s. Good tutorials included interactive demonstrations, such as exploring parametric equations on an online graphing calculator, whereas the not-as-good ones had content that were pitched at too high of a level. Based on these experiences and having demonstrated for 10 hours, I hopefully can share some tips on demonstrating through describing what one would call a “typical” 9am Atmospheric Physics virtual problems class. 

PhD Demonstrating 101 

You, a PhD student, have just been allocated the role as demonstrator on Campus Jobs and are excited about the £14.83 per hour pay. With the first problems class happening in just a week’s time, you start thinking about tools you will need to give these MSc students the best learning experience. A pencil, paper, calculator and that handy Thermal Physics of the Atmosphere textbook would certainly suffice for face-to-face classes. The only difference this year: You will be running virtual classes! This means that moist-adiabatic lapse rate equation you have quickly scribbled down on paper may not show well on a pixelated video call due to a “poor (connection) experience” from Blackboard. How are you going to prevent this familiar situation from happening? 

Figure 1: Laptop with an iPad with a virtual whiteboard for illustrating diagrams and equations to be shown on Blackboard Collaborate. 

In my toolbox, I have an iPad and an Apple pencil for me to draw diagrams and write equations. The laptop’s screen is linked to the iPad with Google Jamboard running and could be shared on Blackboard Collaborate. Here I offer my first tip: 

  1. Explore tools available to design workflows for content delivery and decide on one that works well 

Days before the problems class, you wonder whether you have done enough preparation. Have you read through and completed the problem sheet; ready to answer those burning questions from the students you will be demonstrating for? It is important you… 

Figure 2: Snippet of type-written worked solutions for the Atmospheric Physics MSc module. 

  1. Have your worked solutions to refer to during class 

A good way to ensure you are able to resolve queries about problem sheet questions is to have a version of your own working. This could be as simple as some written out points, or in my case, fully type-written solutions, just so I have details of each step on hand. In some of my fully worked solutions, I added comments for steps where I found the learning curve was quite steep and annotated places where students may run into potential problems. 

Students seem to take interest in these worked solutions, but here I must recommend… 

  1. Do not send out or show your entire worked solutions 

It is arguable whether worked solutions will help students who have attempted all problems seriously, but the bigger issue lies in those who have not even given the problems a try. As a demonstrator, I often explain the importance of struggling through the multiple steps needed to solve and understand a physics problem. My worked solutions usually present what I consider to be the quick and more refined way to the numerical solution, but usually are not the most intuitive route. On that note, how then are you supposed to help someone stuck on a problem? 

It may be tempting to show snippets of your solutions to help someone stuck on a certain part of a problem. Unfortunately, I found this did not work very well. Students can end up disregarding their own attempt and copy down what they regard as the “model answer”. (A cheeky student would have taken multiple screenshots while I scrolled through my worked solutions on the shared screen…) What I found worked better in breakout groups was for the student(s) to explain how they got stuck.  

For example, I once had a few students ask me how they should work out the boiling temperature from saturated vapour pressure using Tetens’ formula. However, my worked solutions solved this directly using the Clausius-Clapeyron equation. Instead of showing them my answer, I arrived at the point where they got stuck (red in Figure 3), essentially putting myself in their shoes. From that point, I was able to give small hints in the correct direction. Using their method, we worked together towards a solution for the problem (black in Figure 3). Here is another tip: 

  1. Work through the problem from your students’ perspective 

Figure 3: Google Jamboard slide showing how Tetens’ formula is rearranged. Red shows where some students got up to in the question, whereas black is further working to reach a solution. 

This again illustrates the point on there being no “model answer”. As in many scientific fields, there exist multiple path functions that get you from a problem to a plausible solution, and the preference for such a path is unique to us all. 

There will always be a group of diligent students who gave the problem sheet a serious attempt prior to the class. You will find they only take less than 30 minutes to check their understanding and numerical solutions with you, and they might do their own thing afterwards. This is the perfect opportunity to… 

  1. Present bonus material to stretch students further 

Some ideas include asking for a physical interpretation from their mathematical result, or looking for other (potentially more efficient) methods of deriving their result. For example, I asked students to deduce a cycle describing the Stirling engine on a TS diagram, instead of the pV diagram they had already drawn out as asked by the problem sheet.  

Figure 4: A spreadsheet showing the content coverage of each past exam question 

I also have a table of past exam questions, with traffic light colours indicating which parts of the syllabus they cover. If a student would like to familiarise themselves with the exam style, I could recommend one or two questions using this spreadsheet. 

On the other hand, there may be the occasional group who have no idea where equation (9.11) on page 168 of the notes came from, or a student who would like the extra-reassurance of more mathematical help on a certain problem. As a final tip, I try to cater to these extra requests by… 

  1. Staying a little longer to answer a final few questions 

The best demonstrators are approachable, and go the extra mile to cater to the needs of the whole range of students they teach, with an understanding of their perspectives. After all, being a demonstrator is not only about students’ learning from teaching, but also your learning by teaching! 

I would welcome your ideas about demonstrating as a PhD. Feel free to contact me at brian.lo@pgr.reading.ac.uk if you would like to discuss! 

Visiting Scientist Week Preview: Laure Zanna

Kaja Milczewska – k.m.milczewska@pgr.reading.ac.uk

As per annual tradition in the Meteorology Department, PhD students have chosen a distinguished scientist to visit the department for one week. Previous years’ visitors include Prof. Tapio Schneider (Caltech), Prof. Olivia Romppainmen-Martius (University of Bern), and Prof. Cecilia Bitz (University of Washington). This year’s winning vote was New York University’s Prof. Laure Zanna, who will be visiting the department virtually1 between 2 – 6th November. 

Laure is an oceanographer and climate scientist whose career so far has spanned three continents, won her an American Meteorological Society (AMS) Early Careers’ award for “exceptionally creative” science this year, and netted her 600 citations in the last two years.  Her research interests encompass ocean turbulence, climate dynamics, predictability, machine learning and more. Some of the many topics of her published papers include the uncertainty in projections of ocean heat uptake; ocean turbulence parametrisations; predictions of seasonal to decadal sea surface temperatures in the Atlantic using simple statistical models and machine learning to inform prediction of extreme events. Besides being an exceptional scientist, speaker and educator, Laure is a down-to-Earth and friendly person, described by the Climate Scientists podcast’s Dan Jones as ‘a really great person who helps to tie the whole community together’.

As someone who had received their PhD only just over a decade ago, we thought Laure would be the perfect candidate to inspire us and our science through sharing some of her academic experiences with us. Before her visit next week, Laure kindly answered some interview-style questions for this week’s Social Metwork blog post.

Q: What inspired you to research oceanography and climate in the first place?

A: I always enjoyed math and physics. The possibility of using these disciplines to study scientific problems that I could “see” was very appealing.

Q: Why were you drawn to machine learning?

A: The power of machine learning (ML) to advance fields such as natural processing language or computer science is indisputable. I was excited by the premise of ML for climate science. In particular, can ML help deepen our understanding of certain aspects of the climate systems (e.g. interactions between scales or interactions between the ocean and atmosphere)? Can ML improve the representation of small-scale processes in climate models? ML, by itself, is not enough but combined with our physical understanding of the climate system could push the field forward.

Q: Can you give us an idea of what’s the most exciting research you are working on right now?

A: This is impossible. I work on 2 main areas of research right now: understanding and parameterizing ocean mesoscale eddies and understanding the role of the oceans in climate. I am passionate and excited about both topics. Hopefully, you will hear about both of them during the week.

Q: When did you realise/decide you were going to remain in academia?

A: I decided that I wanted to try and stay in academia in the last year of my PhD.  I was lucky enough to be able to.

Q: What is your favourite part of your job?

A: Working with my group!  The students and postdocs in the group have different expertise but all are passionate about their research. They make the work and the research more fun, more challenging, and more inspiring.

We are honoured to have our invitation accepted by Laure and are eagerly anticipating answers to more of these kind of questions throughout next week’s conversations.  Laure will be presenting a seminar titled, “Machine learning for physics-discovery and climate modelling” during the Monday Departmental Seminar series, as well as another seminar in the Climate and Ocean Dynamics research group, titled “Understanding past and future ocean warming”. She will also give a career-focused session at PhD group and, of course, engage with both the PhD students and staff on an individual basis during one-to-one meetings. We are grateful and delighted to be able to welcome Laure to the Meteorology department despite the various difficulties the year 2020 has posed on everyone, so come along to next week’s events!


1In true 2020 curve-ball style, of course.

Organising a virtual conference

Gwyneth Matthews – g.r.matthews@pgr.reading.ac.uk

A Doctoral Training Programme (DTP) provides funding, training, and opportunities for many PhD students in our department. Every year three environmentally focused DTPs: the SCENARIO NERC DTP, the London NERC DTP, and the Science and Solutions for a Changing Planet (SSCP) DTP, combine forces to hold a conference bringing together hundreds of PhD students to present their work and to network. As for many conferences in 2020, COVID19 disrupted our plans for the Joint DTP conference.  Usually the conference is hosted at one of the universities involved with a DTP however, this year it was held virtually using a mixture of Zoom and Slack. 

The decision to go virtual was difficult. We had to decide early in the pandemic when we didn’t know how long the lockdown would last nor what restrictions would be in place in September. If possible, we wanted to keep the conference in-person so that attendees got the full experience as it’s often the first time the new cohort meet and one of the few chances for the DTPs to mingle. However, as meeting and mingling was, and is, very much discouraged, making the decision to go virtual early on meant we had time to re-organise.  

Figure 1 – It was initially planned to hold the conference at the University of Surrey campus, which is located in Guildford, Surrey and hosts some students from the SCENARIO NERC DTP. The conference was instead held on Slack, an online communication platform that allows content to be divided into channels, and presentation sessions were hosted on Zoom.

When we thought we were organising a conference to be held at the University of Surrey, the main theme was “Engaging Sustainability” with the aim of making the conference as sustainable as possible. Since one of the often-made criticisms of conferences, especially those within the environmental fields, is the impact of large numbers of people travelling to one place, a virtual conference has obvious environmental benefits. An additional benefit was that we could invite guest speakers, such as Mya-Rose Craig (aka Bird Girl @birdgirluk), who may not have been able to attend if the event was held in person. It was also easier for some participants who had other commitments, such as childcare, to attend, although poor internet connection was an issue for others. 

The pandemic exposed, and often enhanced, many issues within academia and society in general. A questionnaire sent out before the event showed that most attendees were finding working from home and all other pandemic induced changes exhausting and mentally challenging. The recent Black Lives Matter protests around the world and the disproportionate impact of COVID on ethnic minority communities highlighted both the overt and systemic racism that is still prevalent in society. The UK Research and Innovation COVID funding controversy, and an increased focus on the challenges faced by the LGBTQ+ researchers emphasised the inequalities and poor representation specifically experienced in academia. Scientists working at the forefront of the pandemic response faced the challenge of providing clear information to enable people and policy makers to take life-disrupting actions before they are directly impacted; a challenge familiar to climate and environmental scientists. These issues gave us our topics for the external sessions which focused on wellbeing, inclusivity and diversity in academia, and communicating research.  

Barring technical difficulties, oral presentations are easy to replicate online, however, virtual conferences held earlier this year often had issues with recreating the poster sessions. Attempting to learn from these snags, instead of replicating an in-person poster session and possibly producing a poor-quality knock-off, participants were asked to create an animated “Twitter poster”. These were required to describe the key points of their research in a simple format that could be shared on social media and that was accessible to a non-expert. The posters were available for comments and questions throughout the two days in one easy-to-find location. Many of the participants shared their posters on Twitter after the conference using the conference hashtag #JointDTPCon.  

Another issue we faced was how to run a social and networking event. We kept the social event simple. A quiz. A pandemic classic with a fantastic double act as hosts. Randomly assigned teams meant that new connections could be made. However, the quiz was held online and after a full day of video calls most people didn’t want to spend their evenings also starring at a screen.  

Fig 2 – Jo Herschan and Lucinda King, members of the SCENARIO DTP and on the conference organising committee, hosted an entertaining quiz on the first night of the conference. An ethical objects photo round linked the quiz to the conference’s main theme.

With everyone having stayed at home and everything being conducted virtually for a few months by the time of our conference, Zoom fatigue was an issue we were aware could occur and tried to counter as much as possible during the day without losing any of the exciting new research being presented. In the weeks running up to the conference we had several discussions about how to encourage people to move throughout the two days without missing any of the sessions they wanted to attend. We decided on two ideas: a yoga session and a walking challenge. The yoga session was a success and not only gave participants an opportunity to stretch in the middle of the day but also linked strongly to our theme of researcher wellbeing. The walking challenge was not as successful. The aim was that collectively the conference participants would walk the distance from Land’s End to John O’Groats. We did not make it that far; but we did make it out of Cornwall. 

Fig 3 – Using World Walking to track the distance, we intended to collectively walk the 1576km (or 2,299,172 steps) from Land’s End to John O’Groats. This may have been an optimistic endeavour as we only achieved 235km (343, 311 steps).  

Helping to organise a virtual conference as part of an enthusiastic committee was a lot of fun and attending the conference and learning about the research being undertaken (from fungi in Kew Gardens to tigers in North Korea) was even more fun. There is still enormous room for improvement in virtual conferences, but since they aren’t as well established as traditional in-person conferences there’s also a lot of flexibility for each conference to be designed differently. Once we’re through the pandemic and in-person conferences return it’d be nice for some of these benefits to be maintained as hybrid conferences are designed.