Geomagnetic indices are used to characterise the levels of disturbance in the Earth's magnetic field. The various sources of the Earth's magnetic field are complex and the levels of disturbances have both spatial and time dependencies. Historically the need for more than one index to describe the activity of the Earth's magnetic field has arisen.

In this product both local 3-hourly K-indices for the United Kingdom and planetary 3-hourly Kp, ap and aa indices, which are all mid-latitude K-index based, are offered. Daily-averaged versions of the planetary indices - Ap and Aa - are also presented.

Also included is B_GIC index which is provided at 1-minute cadence, and designed to indicate the level of GIC in the UK power grid.

Real-time Dst (ASC) is also included. It is provided at 1-minute cadence and indicates the intensity of geomagnetic activity over the Atlantic region.

The telluric index is a 3-hourly index designed to characterise disturbances in the geoelectric field.

Using the Select Data dialog you can view tables and plots of real-time nowcasts and forecasts, download data, as well as review historical data sets.

Use the Information drop down menu to see a description of the index you have selected.

Geomagnetic forecasts and alerts are important for monitoring disturbances in the Earth's magnetic field.

There are three forecasts of geomagnetic indices (which are used to characterise the level of disturbance of the Earth's magnetic field) derived using automated algorithms. The global ap and regional K_GBI indices are predicted for each 3-hour interval throughout the next 3 days (72 hours), and the daily Ap index is forecast for the next 27 days.

Also included are the daily forecasts of space weather and its expected impact on geomagnetic activity, which are put together by the forecaster on duty at the British Geological Survey and issued every weekday.

Alerts are issued automatically for each of the contributing BGS operated observatories when geomagnetic activity crosses defined storm thresholds.

Using the Select Data dialog you can view tables and plots of real-time forecasts and alerts, and download data.

Use the Information drop down menu to see a description of the forecast or alert you have selected.

The British Geological Survey (BGS) operates three magnetic observatories in the United Kingdom.

These provide the high quality, near-real-time data that underpin products provided to both commercial and academic users.

The observatories provide a good spatial coverage across the country. They are located in Lerwick (Shetland Islands), Eskdalemuir (Scottish Borders) and Hartland (North Devon). These observatories have operated for many years, providing a long-term record of changes in the magnetic field.

The magnetic field is sampled every second and these data are filtered to one-minute mean values.

The electric field at each UK observatory is also measured, collecting data at 10Hz before filtering to ten-second values. These data have been collected since Nov 2012 at Eskdalemuir and from 2013 at Lerwick and Hartland.

Images of the aurora are captured by cameras at the Lerwick and Eskdalemuir observatories if an activity threshold is exceeded. A selection of captured images is available to view.

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BGS observatory codes and locations

Geomagnetic disturbances resulting from space weather can lead to disruption in ground-based technological infrastructure. During a geomagnetic storm the Earth's magnetic field becomes highly variable which leads to electrical currents being induced in the ground, called Geomagnetically Induced Currents (GICs). These GICs can flow into grounded infrastructure, such as transformers in a power network, or buried steel pipelines, causing disruption and, in the worst cases, damage.

Real-time measurements of the geomagnetic field from the 3 UK observatories are used in combination with a model of the conductivity structure of the ground to model the electric field induced across the UK. This electric field is then used to model the currents flowing in technological networks, such as the power grid and high-pressure gas transmission network.

In this product the modelled surface electric field is presented on a map of UK and Ireland. The peak and average GIC in the UK power grid, and Pipe-to-Soil Potentials (PSPs) in UK pipeline-networks are presented for the whole UK as well as Scotland, England and Wales separately. Also presented are the peak and average PSPs for a pipeline along the East coast of Scotland.

Using the Select Data dialog you can choose the model output of interest. The electric field model is displayed as maps, and the GIC and PSP models as tables and plots. Each are of near real-time nowcasts as well as allowing review of historical model results. For the GIC data, Scotland, England and Wales can each be selected separately, or you can select data for the UK as a whole. The regions are the same for the PSP data, with the additional ability to select the East of Scotland pipeline. For both GIC and PSP products it is also possible to select and view multiple regions at a time.

Use the Information drop down menu to see a description of the model output you have selected.

The K-indices from the three UK observatories presented here are classed as definitive. The 3-hour K-index is a measure of disturbance in the horizontal components of Earth's magnetic field over a 3-hour interval. Each period is designated with a code in the range 0-9, with 1 or less being 'quiet' and 5 or more indicating a geomagnetic storm.

The K-index was first introduced by Julius Bartels in 1939 and the label comes from the German word Kennziffer meaning "characteristic digit".

The designated code is derived from the range of the variations observed outside the expected normal 'quiet-day' daily variation and the K-scale can be considered quasi-logarithmic.

Additional note about the UK observatory K-index data base:

• Prior to 1991 - Traditional hand scaling methods were used
• From 1991 onwards - Indices are automatically derived

The UK K-indices are available for:

• Lerwick observatory in the Shetland Islands (1940 - yesterday)
• Eskdalemuir observatory in the Scottish Borders (1940 - yesterday)
• Hartland observatory in North Devon (1957 - yesterday)

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BGS K categories and colour code

The 3-hourly aa-index is a simple global geomagnetic activity index. It is derived from the K indices from two approximately antipodal observatories and has units of 1 nT.

Current observatories are Hartland in the UK, operated by the British Geological Survey and Canberra in Australia, operated by Geoscience Australia. The observatories used in the index derrivation have changed over the time span of the series. More details can be found within the relevant section of the BGS geomagnetism website.

Based on data from only two observatories, the aa-index is the simplest of all the K-based planetary indices. Averaging over 12 hours or longer ensures a good correlation with the ap and am indices, which are derived using data from more extensive observatory networks.

The advantages of the aa indices are that the time series spans further back (to 1868) than any of the other 3-hourly planetary index time series; and they are relatively simple to derive in near-real time.

The daily Aa index is the average of the eight 3-hourly aa values for that day.

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About the data

Rollover the data values in the table for pop-up information about the data

Data supplied here are derived by the British Geological Survey with final values available weekly following the publication of the Canberra K indices. Definitive data are marked as "BGS-definitive".

In between the weekly updates, values are estimated. All estimates are marked as "BGS-estimate".

Nowcasts (values provided for the current time period) are available when input data covering at least 10% of the time period are available. i.e. 18 minutes within a 3 hour period and 2 hours, 24 minutes within a day.
Nowcasts are therefore likely to change from one computation to the next (in this case, every 5 minutes) as new data become available. These are marked at "BGS-nowcast".

Definitive aa are published by the International Service for Geomagnetic Indices (ISGI), a service of the International Association of Geomagnetism and Aeronomy (IAGA).

Data in JSON format is previewed and can be downloaded as a file.

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BGS aa categories and colour code

The 3-hour Kp-index is a mid-latitude/sub-auroral planetary magnetic activity index, first devised by Bartels (1939). As an intermediate product derived in the computation of ap, it is based on a quasi-logarithmic 28 point scale, ranging from 0 to 9, with sub-divisions of one third between each whole value.

The Kp-index is calculated by combining the local K-indices at 13 magnetic observatories. These provide the peak-to-peak range (after discounting local and seasonal quiet diurnal variations) in activity in the horizontal magnetic field over each 3-hour UT interval. Before final computation of Kp, each of the local K-indices are standardised to discount further diurnal, seasonal and latitudinal biases

Although classed as a global index, historically the Kp network of observatories was heavily weighted to the northern hemisphere, in particular to Europe and Northern America. In order to maintain homogeniety over the entire Kp and ap time series the same network has been preserved through time as far as possible.

The Kp-index was officially adopted in 1951 by what is now the International Association for Geomagnetism and Aeronomy (IAGA) and the series was extended backwards to 1932. These days, twice per month, the definitive values of Kp are published by GFZ German Research Centre for Geosciences on behalf of the International Service for Geomagnetic Indices (ISGI), a service of IAGA.

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About the data

Data supplied here include the ISGI definitive values with estimates and nowcasts derived by BGS in between the twice-monthly updates.

Rollover the data values in the table for pop-up information. Definitive data are marked as "IGSI-definitive". All estimates are marked with the letters "BGS-estimate".

Nowcasts (values provided for the current time period) are available when input data covering at least 10% of the time period are available. i.e. 18 minutes within a 3 hour period and 2 hours, 24 minutes within a day.
Nowcasts are therefore likely to change from one computation to the next (in this case, every 5 minutes) as new data become available. These are marked at "BGS-nowcast".

Data in JSON format is previewed and can be downloaded as a file.

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The Kp-index is a global geomagnetic activity index.

BGS Kp categories and colour code

The 3-hourly ap-index is a planetary magnetic activity index on a linear scale with units of 2nT. Devised by Bartels (1939) and related to the Kp-index, which is the quasi-logarithmic equivalent, ap is a measure of global geomagnetic activity at mid- and sub-auroral latitudes.

The ap-index is calculated from the peak-to-peak range (after discounting local and seasonal quiet diurnal variations) in activity in the horizontal magnetic field at 13 (mainly northern hemisphere) magnetic observatories over each 3-hour UT interval. Averaging the eight 3-hourly ap values over a day provides the daily Ap index.

Twice per month, the definitive values of ap and Ap are published by GFZ German Research Centre for Geosciences on behalf of the International Service of Geomagnetic Indices (ISGI), a service of the International Association of Geomagnetism and Aeronomy (IAGA).

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About the data

Data supplied here include the ISGI definitive values with estimates and nowcasts derived by BGS in between the twice-monthly updates.

Rollover the data values in the table for pop-up information. Definitive data are marked as "IGSI-definitive". All estimates are marked with the letters "BGS-estimate".

Nowcasts (values provided for the current time period) are available when input data covering at least 10% of the time period are available. i.e. 18 minutes within a 3 hour period and 2 hours, 24 minutes within a day.
Nowcasts are therefore likely to change from one computation to the next (in this case, every 5 minutes) as new data become available. These are marked at "BGS-nowcast".

Data in JSON format is previewed and can be downloaded as a file.

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BGS Ap categories and colour code

The daily Ap index is the average of the eight 3-hourly ap values for that day.

The 3-hourly ap-index is a planetary magnetic activity index on a linear scale with units of 2nT. Devised by Bartels (1939) and related to the Kp-index, which is the quasi-logarithmic equivalent, ap is a measure of global geomagnetic activity at mid- and sub-auroral latitudes.

The ap-index is calculated from the peak-to-peak range (after discounting local and seasonal quiet diurnal variations) in activity in the horizontal magnetic field at 13 (mainly northern hemisphere) magnetic observatories over each 3-hour UT interval. Averaging the eight 3-hourly ap values over a day provides the daily Ap index.

Twice per month, the definitive values of ap and Ap are published by GFZ German Research Centre for Geosciences on behalf of the International Service of Geomagnetic Indices (ISGI), a service of the International Association of Geomagnetism and Aeronomy (IAGA).

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About the data

Data supplied here include the ISGI definitive values with estimates and nowcasts derived by BGS in between the twice-monthly updates.

Rollover the data values in the table for pop-up information. Definitive data are marked as "IGSI-definitive". All estimates are marked with the letters "BGS-estimate".

Nowcasts (values provided for the current time period) are available when input data covering at least 10% of the time period are available. i.e. 18 minutes within a 3 hour period and 2 hours, 24 minutes within a day.
Nowcasts are therefore likely to change from one computation to the next (in this case, every 5 minutes) as new data become available. These are marked at "BGS-nowcast".

Data in JSON format is previewed and can be downloaded as a file.

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BGS Ap categories and colour code

The daily Aa index is the average of the eight 3-hourly aa values for that day.

The 3-hourly aa-index is a simple global geomagnetic activity index. It is derived from the K indices from two approximately antipodal observatories and has units of 1 nT.

Current observatories are Hartland in the UK, operated by the British Geological Survey and Canberra in Australia, operated by Geoscience Australia. The observatories used in the index derrivation have changed over the time span of the series. More details can be found within the relevant section of the BGS geomagnetism website.

Based on data from only two observatories, the aa-index is the simplest of all the K-based planetary indices. Averaging over 12 hours or longer ensures a good correlation with the ap and am indices, which are derived using data from more extensive observatory networks.

The advantages of the aa indices are that the time series spans further back (to 1868) than any of the other 3-hourly planetary index time series; and they are relatively simple to derive in near-real time.

The daily Aa index is the average of the eight 3-hourly aa values for that day.

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About the data

Rollover the data values in the table for pop-up information about the data

Data supplied here are derived by the British Geological Survey with final values available weekly following the publication of the Canberra K indices. Definitive data are marked as "BGS-definitive".

In between the weekly updates, values are estimated. All estimates are marked as "BGS-estimate".

Nowcasts (values provided for the current time period) are available when input data covering at least 10% of the time period are available. i.e. 18 minutes within a 3 hour period and 2 hours, 24 minutes within a day.
Nowcasts are therefore likely to change from one computation to the next (in this case, every 5 minutes) as new data become available. These are marked at "BGS-nowcast".

Definitive aa are published by the International Service for Geomagnetic Indices (ISGI), a service of the International Association of Geomagnetism and Aeronomy (IAGA).

Data in JSON format is previewed and can be downloaded as a file.

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BGS aa categories and colour code

The 3-hourly K_GBI index is a regional version of the planetary Kp magnetic activity index covering UK and Eire. It is based on a quasi-logarithmic 28 point scale, ranging from 0 to 9, with sub-divisions of one third between each whole value.

The K_GBI index is calculated by combining the local K-indices from magnetic observatories in the UK and in Ireland (Note: currently the Ireland data are unavailable for real-time production however these will be added as soon as possible). The local K-indices provide the peak-to-peak range (after discounting local and seasonal quiet diurnal variations) in activity in the horizontal magnetic field over each 3-hour UT interval. Before final computation of K_GBI, each of the local K-indices are standardised, using the same method as Bartels devised for Kp, to discount further diurnal, seasonal and latitudinal biases

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About the data

Data supplied here are estimates and nowcasts derived by BGS.

Rollover the data values in the table for pop-up information. All estimates are marked with the letters "BGS-estimate".

Nowcasts (values provided for the current time period) are available when input data covering at least 10% of the time period are available. i.e. 18 minutes within a 3 hour period

Nowcasts are therefore likely to change from one computation to the next (in this case, every 5 minutes) as new data become available. These are marked as "BGS-nowcast".

Data in JSON format is previewed and can be downloaded as a file.

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BGS Kgbi categories and colour code

The Ap-index is a daily planetary magnetic activity index on a linear scale with units of 2nT. It is a measure of global geomagnetic activity levels at mid- and sub-auroral latitudes.

The Ap forecasts are for the next 27 days, with today counting as day 1. They are derived using a combination of a linear and non-linear methods. The first three days are predicted using a neural network with the Ap time series itself and a solar activity index time series used as input data. The remaining predictions (from day 4 to day 27) are produced from auto-regressive, integrated, moving-average (ARIMA) models built using the Ap time series as input.

The forecast models are normally run once per day at around 07:00UT.

The plot of the forecast shows a mixture of forecast and estimated data. A grey background is shown on the plot to indicate the section of data that is not a forecast.

Data in JSON format is previewed and can be downloaded as a file.

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BGS Ap categories and colour code

The ap-index is a 3-hour planetary magnetic activity index on a linear scale with units of 2nT. It is a measure of global geomagnetic activity levels at mid- and sub-auroral latitudes.

The ap forecasts are for the next 72 hours (or 3 days). They are derived from auto-regressive, integrated, moving-average (ARIMA) linear models built using the ap time series as input.

The forecast models are normally re-run every 10 minutes as the most recent ap (estimates and nowcast) are updated.

The plot of the forecast shows a mixture of forecast and estimated data. A grey background is shown on the plot to indicate the section of data that is not a forecast.

Data in JSON format is previewed and can be downloaded as a file.

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BGS Ap categories and colour code

The 3-hourly K_GBI index is a regional version of the planetary Kp magnetic activity index. It is based on a quasi-logarithmic 28 point scale, ranging from 0 to 9, with sub-divisions of one third between each whole value.

The K_GBI index forecasts are for the next 72 hours (or 3 days). They are derived from auto-regressive, integrated, moving-average (ARIMA) linear models built using the K_GBI time series as input.

The forecast models are normally re-run every 10 minutes as the most recent K_GBI (estimates and nowcast) are updated. The plot of the forecast shows a mixture of forecast and estimated data. A grey background is shown on the plot to indicate the section of data that is not a forecast.

Data in JSON format is previewed and can be downloaded as a file.

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BGS Kgbi categories and colour code

Rapid variations of the geomagnetic field, caused by space weather, produce an electric field in the Earth's surface. This electric field is the source of electrical currents - called Geomagnetically Induced Currents or GIC - that can, for example, cause damage to transformers in the power grid and cause corrosion to pipelines.

The BGS GIC index, Bgic is a measure of geomagnetic activity designed to indicate the level of geomagnetically induced current (GIC) in the UK power grid. It is based on magnetic field measurements at the Eskdalemuir geomagnetic observatory and has a 1-minute cadence.

Bgic is categorised into 10 levels of activity using thesholds based on rate-of-occurence (shown in the table below). Categories UKG1-UKG5 are based on the same rates of occurrence as the NOAA scales for geomagnetic storms G1-G5.

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B_GIC index categories and colour code

Dst (Disturbance Storm Time) is an index designed to measure the intensity of geomagnetic activity over the Atlantic region.

Original attempts for defining Dst were made by Kertz (1958 and 1964) and Sugiura (1964) with a derivation scheme first proposed by Sugiura and Hendricks (1967) and further improved by Sugiura and coworkers (1969) when it was adopted by the International Association for Geomagnetism and Aeronomy (IAGA). The definitive values of Dst are published by Data Analysis Center for Geomagnetism and Space Magnetism, Kyoto, Japan on behalf of the International Service for Geomagnetic Indices (ISGI), a service of IAGA.

The version presented here is an estimate, derived from measurements made at the near-equatorial magnetic observatory on Ascension Island (ASC), in the Atlantic. Dst (ASC) index is derived from the ASC one-minute horizontal magnetic field variations.

Following the method deployed for the derivation of the official Dst, the secular variation trend and solar quiet (Sq) diurnal variations are estimated and removed from the observatory measurements. The data are then transformed to the dipole equator equivalent, giving Dst (ASC).

About the data:

Data supplied here are real-time estimates derived by BGS and, unlike the definitive Dst, which is an hourly index, Dst (ASC) is computed for every one-minute.

Rollover the data values on the plot or in the table for pop-up information. All estimates are marked with the letters "BGS-estimate".

Data in JSON format is previewed and can be downloaded as a file.

The 3-hour telluric index is a measure of disturbance in the horizontal component of the geoelectric field over a 3-hour interval. Each period is designated with a code in the range 0-9, with 1 or less being 'quiet' and 5 or more indicating storm levels.

The designated code is derived from the range of the variations in each 3-hour period

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BGS t categories and colour code

The BGS human global geomagnetic activity forecast is a text-based forecast for the next three 24-hour periods from noon to noon (UTC), put together by the forecaster on duty. A forecast is created every weekday morning, summarising the expected average and maximum global geomagnetic activity levels for each of the next three forecast intervals (where each interval begins at noon (GMT) on the first day and ends at noon the next day). The geomagnetic activity levels over the previous 24 hours (72 hours on a Monday) are also shown for context

The text in the comments section provides an explanation for the forecast activity levels, including information about any Solar sources of space weather and the solar wind conditions.

The activity levels used are based on the Kp index and colour-coded to match (see table below for the categories).

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The Kp-index is a global geomagnetic activity index.

BGS Kp categories and colour code

The map shows the locations of the contributing BGS operated geomagnetic observatories. If an alert is active, a coloured circle is shown at each alert location. The size and colour of the circle corresponds with the alert level at that location. An alert is active if it has been triggered within the past two hours. If there is no active alert, the location marker will show as a grey colour.

The table shows the most recent alerts generated from any of the observatories. If none are within the past 24 hours the page will show text to say that there have been no geomagnetic activity alerts in the last 24-hour period.

Geomagnetic activity alerts are triggered using simple standard deviation over a period of one hour, known as the HSD index. HSD for both Horizontal components - North (X) and East (Y) - of geomagnetic field variations measured at the observatories are used.

HSD is a measure of power in geomagnetic field variations that drive surface electric fields and hence produce GIC in grounded systems. HSD is relatively unaffected by any spikes that would cause false alarms in other indices e.g. range based indices such as K, Kp, aa and ap.

Thresholds have been set for all observatories, which relate the local features of HSD with known properties of the global magnetic field.

The HSD activity thresholds for each observatory are:

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Geomagnetically induced Currents (GICs) are modelled in the UK power network using a combination of magnetic field data, a conductance model and a power network model. The 1-minute magnetic field measurements from the 3 UK observatories are interpolated to provide a grid of magnetic field variations across the whole UK. This is then combined with a model of the surface conductance, based on geology, to calculate the electric field. The power network model is constructed from information provided in the National Grid plc. Electricity Ten Year Statement. Using the modelled electric field the size of GICs flowing through each substation in that power network can then be calculated.

The peak GIC is the largest absolute current modelled at any substation for the selected region of the UK. Plots, tabular data and download for Scotland, England and Wales and the UK are selected using the Select Data dialog.

Data in JSON format is previewed and can be downloaded as a file.

Geomagnetically induced Currents (GICs) are modelled in the UK power network using a combination of magnetic field data, a conductance model and a power network model. The 1-minute magnetic field measurements from the 3 UK observatories are interpolated to provide a grid of magnetic field variations across the whole UK. This is then combined with a model of the surface conductance, based on geology, to calculate the electric field. The power network model is constructed from information provided in the National Grid plc. Electricity Ten Year Statement. Using the modelled electric field the size of GICs flowing through each substation in that power network can then be calculated.

The average GIC is the mean of absolute current modelled at all substations for the selected region of the UK. Plots, tabular data and download for Scotland, England and Wales and the UK are selected using the Select Data dialog.

Data in JSON format is previewed and can be downloaded as a file.

Pipe-to-Soil Potentials (PSPs) are calculated for the UK high-pressure gas transmission system using a combination of magnetic field data, a conductance model and a pipeline network model. The 1-minute magnetic field measurements from the 3 UK observatories are interpolated to provide a grid of magnetic field variations across the whole UK. This grid of magnetic variations is then combined with a model of the surface conductance, based on geology, to calculate the electric field. The model of the UK pipeline network (which is shown on the map below) was created using information available on the National Grid plc. website. The electric field is then used to calculate the size of PSPs at each node in the pipeline model.

The peak PSP magnitude anywhere in the grid (UK), in each of the regions (England, Scotland, Wales) and in the East of Scotland pipeline is then found and shown in the plots, tabular data and download provided here. Select a region or regions using the Select Data dialog.

Data in JSON format is previewed and can be downloaded as a file.

Pipe-to-Soil Potentials (PSPs) are calculated for the UK high-pressure gas transmission system using a combination of magnetic field data, a conductance model and a pipeline network model. The 1-minute magnetic field measurements from the 3 UK observatories are interpolated to provide a grid of magnetic field variations across the whole UK. This grid of magnetic variations is then combined with a model of the surface conductance, based on geology, to calculate the electric field. The model of the UK pipeline network (which is shown on the map below) was created using information available on the National Grid plc. website. The electric field is then used to calculate the size of PSPs at each node in the pipeline model.

The average PSP magnitude anywhere in the grid (UK), in each of the regions (England, Scotland, Wales) and in the East of Scotland pipeline is then found and shown in the plots, tabular data and download provided here. Select a region or regions using the Select Data dialog.

Data in JSON format is previewed and can be downloaded as a file.

The British Geological Survey (BGS) run surface electric field monitoring systems at the three magnetic observatories in the United Kingdom. These measure the changing electric field generated near the Earth's surface.

Rapid variations of the geomagnetic field, caused by space weather, produce an electric field in the Earth's surface. This electric field is the source of geomagnetically induced currents that can, for example, cause damage to transformers in the power grid or cause corrosion to pipelines.

Data are recorded at 10 Hz along East-West and North-South electrode lines and automatically transmitted to BGS. Data are filtered to 0.1Hz before presentation on this site.

DISCLAIMER: The data presented are based on raw measurements without any quality control.

The rate of change of the horizontal magnetic field (dH/dt) for the three UK magnetic observatories is presented.

The plots shown are dH/dt in the X (North) component (top plot), and Y (East) component (bottom plot), in nT/min.

dH/dt rises and falls very rapidly during magnetic storms.

Activity is usually greater in the X (North) component - but not always.

Activity is typically enhanced the further north the observatory is (e.g. usually Lerwick > Eskdalemuir > Hartland).

Low-cost, experimental aurora cameras are in operation at the Lerwick observatory (Shetland Islands) and the Eskdalemuir observatory (Scottish Borders), both in the UK. This product provides a curated set of images recorded at each observatory.

Camera Equipment

The aurora cameras run on Raspberry Pi computers. The camera at Eskdalemuir runs on Raspberry Pi 3 and is equipped with a 5 megapixel sensor and an off-the-shelf lens (2.9mm focal length, f1.6, ~100 degreee FOV). The camera installed at Lerwick runs on Raspberry Pi 4, with a 26 megapixel sensor and a Nikon Fisheye lens (10.5mm focal length, f2.8, 180 degree FOV). Each camera is held in a waterproof box with a transparent Perspex dome. The software to operate the cameras is written in Python.

When are images captured?

The camera software is configured to capture images once a certain geomagnetic activity threshold is reached. The Hourly Standard Deviation (HSD), a local activity measure updated every five minutes, is used for the activity threshold. The current threshold to trigger the camera is set to 30nT at the Lerwick observatory and 10nT at Eskdalemuir. The camera also only operates if it is between the time of local sunset and sunrise. If activity is high enough, and it is dark, it will continue to capture images once a minute until activity drops or the sun rises.

Modelled surface electric field displayed on a map of UK and Ireland as an indicator of space weather hazard to power, pipe-line and rail networks, and overlaid with measured electric field at three UK observatory locations, see BGS product G.140 Horizontal electric field data (UK).

One pair of map images are shown for the Northwards and Eastwards electric field (EX and EY respectively) modelled at a particular time. A collection of all images for single days are available via a dropdown selector. The number of days in the dropdown depend on the selected period. The selected time period can be set from the Select data Button. The default day is the most recent and the most recent pair of images are shown for that day. All images within the selected day are available in the form of a carousel of small images. A slider control, and arrows at either side of the images enable stepping forward and back through the available images.

Clicking on a single small image provides a pop-out larger version of the image.

The geoelectric field in the UK and Ireland is modelled every 15 minutes using real-time measurements of the magnetic field at the three UK observatories (Hartland, Eskdalemuir and Lerwick). The 1-minute magnetic field measurements are interpolated to provide a grid of magnetic field variations across the UK and Ireland. This is then combined with a model of surface conductance, based on the 1:625000 geological map, to calculate the electric field.

There are also long-term measurements of the geo-electric field at the three UK observatories at 10Hz frequency. The rolling 10-minute mean is subtracted to leave the anomalous electric field, and then the maximum anomalous magnetic field is found and plotted on the map.

A coloured scale bar to the right of each image defines the relationship of map colour to field value. A circular marker is shown at each observatory location. The colour of the marker indicates the measured field value at the location, and the size of the circle is proportional to the value.

Main page

To select the data set you want to see, and the range of dates and/or times you want to see it over, click the Select Data button and enter the relevant information in the dialog.

For data sets that can be viewed at different dates and/or times, use the Previous and Next buttons to step backward and forward by the date/time range currently shown on the page. Use the Most Recent button to see the most recently available data. The Next and Most Recent buttons will be disabled when the most recent data is displayed. The Previous button will be disabled when the page is showing the earliest data available for the current data set.

Select Data dialog

Select the data set you want to see from the drop-down menu.

Where applicable, select the observatory (observatories) or region(s) from the drop-down menu.

Where applicable, enter two dates/times separated by '-' in the input box to specify the date/time you want to see. Alternatively, select a date/time range using the date picker.

Data display area

The data display area is either a single panel, or for time series data, is a set of 3 selectable tabs.

The tabs are labelled Plots, Tabular Data and Download Data.

Plots shows a graphical representation of the selected data.

Tabular Data shows the selected data organised in a structured table.

Download Data shows a preview of the selected data in JSON format and provides a Download button that allows the data to be saved as a JSON format file.