Official blog of the Met Office news team

During April, we have been focusing on the topic of climate change and infrastructure, considering the impact of the climate on industries such as energy and transport. In this blog post, we look at this topic at a more local level, sharing information on some of the actions the Met Office is taking to reduce the impact of transport on the climate.

The Met Office Journey to Net Zero strategy includes a focus on business travel and, when our updated baseline is published soon, commuting will also form part of our aim to be a carbon neutral organisation by 2030. As well as reducing business travel, we have also been making changes to our vehicle fleet including both pool cars and bikes. This not only supports our Journey to Net Zero, but also the Greening Government Commitments that one hundred percent of the government car and van fleet will be fully zero emissions at the tailpipe by 31 December 2027.

A greener pool

Two electric pool cars will soon be available for use at our Exeter headquarters for occasions when colleagues need to use this form of transport for business. With charging stations on site (including a number for people to use for personal electric vehicles), this will reduce our reliance on petrol/diesel cars.  

At the end of 2022, we also took delivery of a new pool bike fleet at the Exeter office.  These include six Ridgeback Avenida bikes and two Ridgeback rechargeable Electron bikes in a variety of sizes to suit different riders. These bikes can be booked for business journeys and leisure rides as well as for emergency transport (e.g., if public transport or car sharer is unexpectedly unavailable) and to try out commuting by bike.

Encouraging low carbon commuting

To assess the climate impact of commuting as well as business travel, a recent staff survey was conducted to help us better understand people’s commuting habits. Cycling was our second most common commute method, with many staff making a great effort to use greener travel options; in 2022 we were deserved winners of the National and Global Cycle September Challenge organised by Love to Ride.

The Met Office has long encouraged cycling to work, with excellent facilities available including over 300 covered cycling spaces at our Exeter headquarters along with showers and locker facilities. We are also part of a Cycle to Work scheme to help colleagues spread the cost of buying a bicycle and save on tax and national insurance. More recently, the Met Office has joined the Co Bikes Corporate Rider scheme ensuring our employees can get a discount when using Co Bikes, Exeter’s on-demand electric bike scheme.

Local infrastructure

Cycling and walking are often promoted as the most sustainable form of transport, but the infrastructure needs to be in place to facilitate these options. As well as considering the infrastructure available at our offices, we also contribute where possible to local proposals. Last month, for example, we provided a detailed response to a Devon County Council consultation on the Local Cycling and Walking Infrastructure Plan. As well as providing some scientific context, we also commented on considerations for walking and cycling routes including taking into account the needs of those who have physical disabilities and other accessibility requirements. We look forward to seeing the results of the consultation.

Win-wins      

As well as the climate benefits of reducing emissions by walking and cycling more, these activities also have co-benefits. These win-wins include reducing air pollution and personal health and wellbeing benefits. Next month we will be looking in more detail at the co-benefits of climate action. Follow #GetClimateReady on Twitter to learn more about our monthly topics.

Like any infrastructure, the rail network can be impacted by external factors such as the weather. Met Office scientist, Alice Lake, is part of a team developing a new temperature model designed to help rail networks in the UK minimise these impacts.

The underlying infrastructure
In the past, the UK rail network was made up of tracks laid in separate panels, bolted together. But traditional track joints require significant maintenance; rail ends wear, and bolts need periodic checking and tightening. Therefore, as steel production and manufacturing processes improved, the lengths of the panels progressively increased until the 1960s when the first continuous welded rail was laid, eliminating track joints altogether. Today, continuous welded rail is used as standard across the UK network.

The weather impacts

Since the steel on railway tracks is essentially a very long piece of metal, it can expand or contract significantly in hot and cold weather. Therefore, to increase resilience, rails are pre-stressed to withstand the range of temperatures they’ll typically experience. The so-called ‘stress-free temperature’ (SFT) is the temperature at which the rail is neither in tension nor compression. In the UK, the SFT is 27°C. Other countries may choose higher SFTs – for example, in the US standard SFTs range between 35 and 43°C – which allows their rail to withstand hotter temperatures before expanding. However, this also means that their rails are more susceptible to brittleness and cracks in low winter temperatures.

If the rail temperature exceeds the range in which it is designed to operate, the steel can expand substantially, generating forces which push and pull the railway out of shape. Combined with the forces generated by trains running at high speeds along the tracks, this can lead to buckling. While rare, derailment caused by track buckling can have catastrophic consequences, so blanket speed restrictions are implemented across the UK network when the air temperature is forecast to exceed a set threshold.

Using science for informed decision-making

However, there isn’t a simple relationship between rail temperatures and air temperature. Therefore, at the Met Office, we’re currently developing a new rail surface temperature model, working with key partners to understand their needs. This model uses forecasts of local atmospheric weather parameters (such as air temperature, incoming shortwave and longwave radiation, and amount of precipitation) from numerical weather prediction (NWP) models and then calculates the incoming and outgoing energy at the rail surface. From this, we are able to produce forecasts of local rail surface temperatures. With accurate and precise knowledge of rail surface temperatures, speed restrictions and other preventative measures (such as painting rails white to reduce overheating) could be applied in a more localised and targeted way, minimising disruption to the network.

A changing climate

The latest UK Climate Projections (UKCP18) indicate that we can expect hotter, drier summers as our climate continues to change. Services such as the rail surface temperature model will therefore continue to be critical to ensure industry and business can remain resilient to current and future weather impacts.

Space weather might be a lesser-known forecast from the Met Office, but predicting the occurrence of solar flares, solar radiation storms and coronal mass ejections is vital for range of critical sectors from satellite providers to the aviation industry, as well as for forecasting Aurora Borealis sightings.

In recent weeks aurora sightings have been in the news again, with some as far south as Cardiff reportedly capturing photos of the Northern Lights, which is often the way most of the public is inadvertently aware of space weather.

Has there been more Aurora Borealis activity recently?

In short, yes. But the explanation is well known in the science community and a further increase in space weather activity is expected in the coming years.

Krista Hammond is a Manager at the Met Office Space Weather Operations Centre (MOSWOC). She said: “Activity on the sun, and in particular the number of visible sunspots, varies over roughly an 11-year period, known as the solar cycle.”

The last solar minimum – when the Sun had the lowest frequency of visible sunspots in the solar cycle – occurred in December 2019. This means that the sun’s activity is currently increasing, with the next solar maximum expected around 2025.

Krista added: “Over the coming years, as we continue towards the solar maximum, we can expect to see an increase in the frequency of space weather events, with more chances to see the Aurora Borealis over the UK.”

Finding space to forecast

MOSWOC is one of a handful of 24/7 space weather forecasting centres in the world, with expert forecasters focused on predicting the arrival of impactful space weather events on Earth.

Despite the somewhat predictable nature of the 11-year solar cycle, forecasting specific space weather events can be more challenging, as you might expect when predicting an event on Earth that begins on the Sun around 150 million kilometres away.

Solar flares are sudden releases of energy across the entire electromagnetic spectrum. They are hard to predict, and the energy can be detected in Earth’s atmosphere as soon as 8.5 minutes after the occurrence of a solar flare.

Linked with large flares, solar radiation storms may also occur. These consist of high-energy charged particles, predominantly electrons and protons, and typically take between ten minutes and several hours to arrive at Earth.

Coronal mass ejections (CME) are often associated with flares and are a focus of space weather forecasting. They can take days to reach the Earth and can disturb the Earth’s magnetic field and ionosphere, which is where the Earth’s atmosphere meets space, causing what is known as a geomagnetic storm.

Strong geomagnetic storms have the potential to impact GPS, radio frequencies and some satellite operations but forecasting their arrival can give industries time to mitigate against the worst impacts. They are also the phenomena responsible for the enhanced Aurora Borealis in the Northern Hemisphere or Aurora Australis in the Southern Hemisphere. Find tips on how to take photos of the auroras, courtesy of the Royal Photographic Society.

Last year, the announcement of the Vigil mission highlighted an opportunity to enhance space weather forecasting across the world.

Does space weather link with our weather?

Space weather doesn’t interact with the Earth’s meteorological drivers and doesn’t impact day-to-day forecasting, short of people being more interested in clear skies to see the Northern Lights.

Over a longer period, the impact the solar cycle on global temperatures is negligible and can be responsible for less than 0.05°C differences in global temperature over the course of the 11-year solar cycle. For comparison, global average temperatures have risen by around 1.1°C since the industrial revolution, driven by human-induced climate change.

March is the first month of meteorological spring. But what is the outlook for the month? Are we likely to get more spring-like weather, or perhaps something more reminiscent of winter?

The outlook suggests that March 2023 is more likely to be colder than average. But what is that likely to mean in terms of impacts?

From what we know so far – looking at some of the global drivers of weather – there are increased chances of impacts from cold weather, such as snow, frost and fog, at least for parts of the UK.

Mark Sidaway is a Deputy Chief Meteorologist with the Met Office. He said: “Although we have had a Sudden Stratospheric Warming event and other drivers pointing towards colder conditions in March, at this stage there is a low probability of having widely disruptive winter weather like that of five years ago in March 2018.

“At that time a large area of high pressure became established over Scandinavia, providing a feed of cold air all the way from Arctic Siberia. This brought intense cold to the UK.

“We are expecting an area of high pressure to become increasingly established in an area toward Greenland. This will allow a northerly flow to feed colder air into at least the northern and eastern half of the UK bringing wintry showers.

“The extended outlook shows the possibility for a series of areas of low pressure to come across the Atlantic, and these bring the potential for some more widespread snowfall as they encounter the cold air, although the location and timing of these is very uncertain for now.

“The exact positioning of the high pressure will be key and will greatly affect what weather we see in the UK.”

March 2018 was a record-breaking cold spring, which had been driven by a feature known as Sudden Stratospheric Warming. This happens when air in the stratosphere above the North Pole collapses creating a disturbance of the Stratospheric Polar Vortex – where westerly winds rotate around the North Pole, effectively hemming in the most intense cold air.

When the Stratospheric Polar Vortex breaks down it can encourage the switching of normally westerly winds to an easterly direction. Eventually, this wind reversal can reach the surface, bringing air from an easterly source. In 2018 this resulted in intensely cold air coming to the UK all the way from Arctic Siberia.

Although the globe has experienced another Sudden Stratospheric Warming episode the outcome will not necessarily be a repeat of 2018.

What can we expect from early March?

The most likely scenario is for colder and settled weather, with wintry showers perhaps affecting some northern and eastern areas (mainly coasts), at least at first.

This colder regime moving south across much of the UK, increasing risk of wintry showers, perhaps snow to the higher ground in the north. Temperatures are likely to be below average.

Beyond the first week or so of March confidence in the weather pattern becomes very low, but a preference for blocked broad scale conditions remains which continues to increase potential for colder conditions compared to average.

Spells of rain become more likely, with a chance that some areas could see snow. Some wintry episodes could be disruptive with a combination of snow and strong winds. North-west areas of the UK have the highest chance of remaining drier than average.

Temperatures are most likely to be below average overall during at least the first half of March. But values are expected to be nearer average overall later on. Within this, shorter colder spells remain possible.

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