Space Weather Alert - 15th Feb 2011

What Has Happened?

 

Since 13th February three energetic solar flares have erupted on the Sun and spewed clouds of charged plasma called coronal mass ejections (CMEs) out towards the Earth. The biggest of the three flares (an X2.2 at 01:56, 15th Feb) is the largest in over four years. We need to go back to the 13th Dec 2006 to find a bigger one.

Already one CME arrived on the 14th sparking Valentine's Day displays of the Northern Lights (aurora borealis) further south than usual. See pictures from Northern Ireland in the UK (external link)

The other two CMEs are expected to arrive in the next 24-48 hours. Recent estimates suggest arrival later on the 17th or early 18th Feb. Magnetic storms are likely to follow the arrival of these later CMEs.

Further Northern Lights (aurora) displays are possible some time over the next two nights if skies are clear and the activity peaks in your local night-time.

 

 

 

This solar storm coincides with the release of a rarely seen archive of unique geomagnetic records that provide an insight into space weather stretching back to the Victorian era. Further information below.

 

See BBC Weather Forecasts for clear skies.

See BGS Real-time estimated Ap for global geomagnetic activity levels.

Follow us on Twitter:

@BGSauroraAlert for more occasional aurora alerts

@BGSspaceWeather for daily space weather forecasts

 

How Does Space Weather and Geomagnetic Activity Affect Us?

The Sun exerts profound control over a natural hazard - space weather - that poses a risk to modern technology. This is a hazard we knew little of until the Space Age. The Sun’s control of space weather is exercised through the charged particles and magnetic fields that are carried by the solar wind as it buffets the Earth’s magnetic field.

Episodes of high solar magnetic activity can cause geomagnetic storms on the Earth. This is a fact long recognised through historical records of the aurora borealis, or Northern Lights. However Earthly auroras and geomagnetic storms are just one consequence of the Sun’s changeable nature. So much so that the concept of ‘space weather’ has developed over recent decades to include all solar magnetic effects on the Earth’s environment and all related impacts to technologies in space, in the air and on the ground.

Modern society relies increasingly on technology and much of this technology is space-based and electromagnetic. As such we are increasing our exposure to space weather and to the related geomagnetic hazard.

Communications, global positioning and remote sensing are at risk from space weather. Spacecraft and even high-altitude aircraft suffer from increased radiation during geomagnetic storms. The orbits of low Earth orbit satellites are perturbed and their working lifetimes are decreased. Polar long-haul air flights can be re-directed or postponed. On the ground space weather and geomagnetic storms damage high voltage power grids and oil/gas pipelines around the world.

The potential disruption or long-term loss of any of these systems poses serious questions for governments, industry and society.

How often does this happen?

Space weather follows a natural cycle of activity known as the solar cycle and traditionally measured by the sunspot number. After a lengthy minimum, solar activity is increasing again and in a few years time the Sun will once again be at the peak of its activity. The number of magnetic storms follows a similar cycle with its peak usually lagging behind the solar cycle by one or two years.

It is still scientifically very difficult to predict with any accuracy when a space weather event will occur and how large an impact it will have on the Earth. Research, for example funded through the UK Natural Environment Research Council, is continuing into space weather prediction.

We do know however that once a major solar eruption has occurred, that any space weather impact on the Earth will follow from hours to a few days later.

Victorian Space Weather?

BGS have just released a rarely seen archive of unique geomagnetic records that provide an insight into space weather stretching back to the Victorian era. BGS scientists hope that a study of solar storms in the past will inform the prediction of future space weather and help counter the threat to our national power grid and communication systems.

Rarely seen records of past space weather, dating back 160 years, have been made available online by the BGS. These unique magnetic recordings, known as ‘magnetograms’, provide a glimpse into the history of the Sun’s stormy relationship with planet Earth. BGS scientists hope to gain a better understanding of the potential severity of future space weather by studying the magnetogram archive (www.bgs.ac.uk/data/Magnetograms/home.html).

Alan Thomson, Head of Geomagnetism at the BGS, said “Life today increasingly depends on technologies in space and on the ground that didn’t exist when the magnetic recordings began. Studying the records will tell us what we have to prepare for and plan to make sure systems can resist the threat of solar and magnetic storms.”

He continues “The ‘Carrington Storm’ of 1859 caused fires and electrocuted workers at Victorian telegraph stations. But what else is there in the records that we might find? How might such events affect today’s power grid, if they were to occur again?” Scientists also hope to discover how slow changes in the magnetic fields of both the Sun and the Earth affect our natural environment.

Bob McIntosh, Geo-Information specialist at the BGS, commented “There are more than a quarter of a million records in the archive, many on crumbling photographic paper. Preserving these records digitally is essential for the future and for enabling access to the public and scientists alike. ” Ellen Clarke, Geomagnetism scientist, added “The on-line photographs contain UK magnetic observatory records from 1846 to 1940. Future releases will extend that up to 1983, when digital recording was introduced.”

Alan Thomson said “Making these records available now marks the 175th anniversary of the explorer Alexander Von Humboldt’s plea to the British government to join the ‘magnetic crusade’ of the Victorian era. Long-term monitoring of the Earth’s magnetic field and the science of geomagnetism in the UK, in many ways, date from this event.”

What is BGS’ Role in Monitoring and Predicting Space Weather?

The BGS Geomagnetism team measures, records, models and interprets variations in the Earth’s natural magnetic fields, across the world and over time. Our data and expertise help to develop scientific understanding of the evolution of the solid Earth and its atmospheric, ocean and space environments. We also provide geomagnetic products and services to industry and academics and we use our knowledge to inform and educate the public, government and the private sector.

The Geomagnetism team provides 24/7 monitoring of geomagnetic activity, 3-day ahead magnetic activity forecasts, and post-event analysis of storm impacts on technology, including the UK power network.

Background

 

One way that scientists measure the strength of solar activity is through the brightness of any solar flare that accompanies each event.

Table 1 shows the strength of the recent flare activity that caused the space weather event (highlighted), in comparison with the top 10 flares known since 1970s.

Rank	Year/Month/Day	X-Ray Class
1	2003/11/04	X28+
2	2001/04/02, 1989/08/16	X20.0
3	2003/10/28	X17.2
4	2005/09/07	X17
5	1989/03/06, 1978/07/11	X15.0
6	2001/04/15	X14.4
7	1984/04/24, 1989/10/19	X13.0
8	1982/12/15	X12.9
9	1982/06/06, 1991/06/01, 1991/06/04, 1991/06/06, 1991/06/11, 1991/06/15	X12.0
10	1982/12/17, 1984/05/20	X10.1
=165	2011/02/15	X2.2

Table 1. How does the recent solar activity compare with the largest known solar flares of recent decades?
‘X-Ray Class’ denotes flare magnitude in units of 10^-4 W/m², between one and eight Angstroms wavelength.
Source: Spaceweather.com

One way that scientists measure the strength of geomagnetic storms caused by space weather is by how fast the magnetic field changes in time, for example in nT per minute (nT/min). (One nT is approximately 0.002% of the strength of our magnetic field at the surface of the Earth, approximately 50,000 nT). This measure is useful for understanding the potential impact of space weather on important technologies.

Rank	Date	Peak Rate-of-Change (nT/min)
1	13th March 1989	1079.6
2	8th November 1991	804.1
3	30th October 2003	656.5
4	21 October 1989	618.6
5	1st November 1991	515.2

 

Table 2: The top 5 geomagnetic storms known since digital recording began in 1980 in the UK.
The peak value is the largest seen at any of the three UK observatories. Data courtesy BGS (NERC).

 

Glossary

BGS

The British Geological Survey is one of the Natural Environment Research Council's Research Centres.

CME or Coronal Mass Ejection

The eruption of a portion of the outer atmosphere of the Sun into space, caused by rapid changes in its magnetic field. Often occurs along with a solar flare.

Coronal Hole

A region in the Sun’s outer atmosphere (corona) where hot material can flow unrestrained by its magnetic fields out into space.

Flare

Energy released by the explosive reorganisation of magnetic fields within the Sun’s atmosphere.

High Speed Stream

A fast moving stream of solar wind, responsible for magnetic storms.

 

Magnetogram

The variation, minute by minute, of the strength and direction of the Earth’s magnetic field. Measured in units of nano-Tesla (for the strength of the field) or in degrees (direction of the field).

Solar Wind

The ever-present expansion of the Sun’s hot outer atmosphere into the solar system, which carries space weather within it.

 

Sunspot

A region of intense magnetic field in the Sun’s visible outer atmosphere often associated with flares and CMEs.