Taking a fresh look at the weather

Aug 01, 2011
Taking a fresh look at the weather
Credit: University of Manchester

Given the UK’s obsession with the weather, it would seem obvious that the basic understanding of how low pressure systems evolve has been known for a long time.

Instead, some of the biggest storms in the UK’s history, such as the Great Storm of October 1987, did not fit this basic understanding.

With groundbreaking research, Dr David Schultz, from The University of Manchester believes the way we learn about the is wrong and has been wrong for 90 years.

Writing in the journal Bulletin of the American Meteorological Society, Dr Schultz, along with his colleague Professor Geraint Vaughan, has worked out that the traditional model for how low pressure systems evolve is deeply flawed.

The model, used since the 1920s and devised by Norwegian meteorologists, is that when a storm occludes (evolves), it will automatically begin to weaken and pose little danger of severe weather.

However, argues Dr Schultz, this is not the case – occluded storms may well contain strong winds and regions of heavy precipitation.

Naturally, many in the public recognize that. The Great Storm of October 1987 and the Burns’ Day storm of January 1990 were both clear reminders: occluded, but still deadly. Dr Schultz’s new model addresses these weaknesses with the Norwegian model because the prior belief that occluded storms were weak could lead to poorly-informed predictions or forecasts.

Dr Schultz, from the University’s School of Earth, Atmospheric and Environmental Sciences, claims they now know that the deepening of a low pressure system is not dependent on when a cyclone occludes.

Specifically, the new model is called ‘wrap up’, to emphasize that the wind around the occluding cyclone wraps up the low pressure system into an anticlockwise-spiralling cloud pattern.

Dr Schultz said: “With this new interpretation of the occlusion process we can explain why not all low pressure systems occlude – the winds are not strong enough to wrap up the storm.

“The Norwegian model of low pressure systems served us well for many years, but it’s time to move on.

"This new model is better than the Norwegian model at explaining the available observations of the structure and evolution of occluded low pressure systems."

Dr Schultz argues that how we teach about low pressure systems is wrong, and that textbooks, public information guides and models will need to be radically updated to ensure the next generation of meteorologists, as well as the public, are in possession of all the facts.

He added: “All books from postgraduate-level textbooks to basic weather books for the public need to be rewritten to convey the correct understanding. What we teach students in school needs to be changed. And forecasters need to be retrained to have this latest information.”

Another result of Dr Schultz’s research is a better explanation for the observed structure of storms. Previously, meteorologists believed that occluded cyclones and their associated fronts could tilt eastward with height or tilt westward with height, roughly in equal measure. This new research demonstrates that westward-tilting occluded fronts are rare and provides an explanation for why.

Dr Schultz added: “I hope that this will help people understand the particular weather conditions associated with these potentially hazardous storms. Yet, this research shows how much more remains for us to learn about the weather around us.”

Explore further: Better forecasts for sea ice under climate change

Related Stories

Measuring NIF's enormous shocks

18 hours ago

NIF experiments generate enormous pressures—many millions of atmospheres—in a short time: just a few billionths of a second. When a pressure source of this type is applied to any material, the pressure ...

How can we search for life on icy moons such as Europa?

18 hours ago

Our solar system is host to a wealth of icy worlds that may have water beneath the surface. The Cassini spacecraft recently uncovered evidence of a possible ocean under the surface of Saturn's moon, Mimas.

How the hummingbird achieves its aerobatic feats

Nov 23, 2014

(Phys.org) —The sight of a tiny hummingbird hovering in front of a flower and then darting to another with lightning speed amazes and delights. But it also leaves watchers with a persistent question: How ...

Estimating the magnetic field of an exoplanet

Nov 20, 2014

Scientists developed a new method which allows to estimate the magnetic field of a distant exoplanet, i.e., a planet, which is located outside the Solar system and orbits a different star. Moreover, they ...

Recommended for you

Better forecasts for sea ice under climate change

7 hours ago

University of Adelaide-led research will help pinpoint the impact of waves on sea ice, which is vulnerable to climate change, particularly in the Arctic where it is rapidly retreating.

"Ferrari of space' yields best map of ocean currents

15 hours ago

A satellite dubbed the "Ferrari of space" has yielded the most accurate model of ocean circulation yet, boosting understanding of the seas and a key impact of global warming, scientists said Tuesday.

Researcher studies deformation of tectonic plates

18 hours ago

Sean Bemis put his hands together side by side to demonstrate two plates of the earth's crust with a smooth boundary running between them. But that boundary is not always smooth and those plates do not always ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

runrig
not rated yet Aug 01, 2011
Don't know where this guy has been or who he has been talking to, but as an ex Met Office Forecaster - since my initial forecaster training in fact, going back 25 years - there has been a better/fuller physical understanding of cyclonic development than the "Norwegian Model". Computer models have evolved in that time along with this understanding as further insights have come along. A much more important aspect in a ( temperate ) depression's development is it's position under the prevailing jet stream and the presence or not of a running short-wave through it ( jet streak ). Warm advection and release of latent heat into the Low is important too and explosive development of an Atlantic depression often takes place when all these aspects are present. The "spin" imbued in the upper atmospheric air as it blows above and over the Low then drags down Stratispheric air into the core inducing instability and further translation of strong wind gradients down to the surface.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.