The index ranges from 0, for low activity, to 9, which means that an intense geomagnetic storm is under way. The following information — from the book Your Guide to the Northern lights and night sky above Iceland published in early — describes how different Kp-indices look like as seen from Iceland:. It nevertheless provides a good idea of what to expect.
Always take a Kp-index forecast with a pinch of salt. There is a pronounced diurnal variation in the K index at a single station, with intervals close to local midnight being substantially more disturbed in comparison with those centered on local noon. This diurnal variation also exhibits seasonal and latitudinal dependence.
Mere averaging of the logarithm of activity was therefore not considered proper unless the stations were densely and evenly distributed over the world.
To overcome this, a standardization procedure was developed by J. Bartels for assigning to each K value a standardized alternate - designated by Ks - which could be more refined than K in the sense that it is given in thirds. The present conversion tables for three seasons have been prepared using selected data from to except Niemegk.
The three seasons are:. Julius Bartels was born August 17, in Magdeburg, Germany. After achieving his PhD in , Bartels worked as a postdoc with A. Schmidt at the Potsdam magnetic observatory. His early works dealt with statistical methods especially in atmospheric, geomagnetic and ionospheric tides. In , Bartels became professor in Eberswalde; in , he became director of the Potsdam Geophysical Institute and full professor at Berlin university.
Between and , he also worked as a research associate at the Department of Terrestrial Magnetism at the Carnegie Institution Washington D. In , J. In , Bartels and his friend S. Chapman published Geomagnetism, a standard work of geophysics until today.
In many of his publications, Bartels developed, used and perfected statistical methods. With these statistical methods, he was able to disprove many widely accepted geophysical models on the one hand and develop some very useful and easy to apply geophysical indices on the other. Among these widely accepted and well known indices is the planetary geomagnetic Kp index. Eliminating regular variations of the Earth's magnetic field, he showed the impact of the Sun's wave and particle radiation.
He recognized that seizing this concept in numbers would form a powerful tool for scientists in the research of solar-terrestrial relations. Bartels knew well that this the Kp tables would only be accepted if they were presented in a clearly arranged and lucid manner.
The striking success of the three-hourly geomagnetic Kp indices is also due to their brilliant representation in the Bartels musical diagram musical scales. Using only geomagnetic data and statistical methods, Bartels claimed the existence of M-regions on the sun that are responsible for geomagnetic activity. Not before - with the Skylab mission - was observational data of coronal holes gained.
The claimed M-regions were identified as coronal holes, which are the source of the fast solar wind that intensifies geomagnetic activity. When he died March 6, , he had contributed much to the reputation of geophysics worldwide. It is reserved for outstanding research in solar-terrestrial sciences. Biographical information extracted from W. Toggle Navigation. Direct access to data download:.
Indices of Global Geomagnetic Activity. News for Kp Index Users: filename ambiguity warning. Try to adapt your eyes to the dark, this will help you see it better.
Quite often the factory minimum brightness is still too bright once your out there and your eyes are properly dark adapted, so you should get an app that makes the screen even darker still. Best place to see the Northern Lights? What is solar max and why is it important? All about the Kp index. Everything you need to know about the Kp number system and viewing auroras at lower latitudes The most important thing to know about aurora watching is the kp index.
How the numbers work The kp number system is just a scale of geomagnetic activity. Geomagnetic Storms Geomagnetic storms are labelled G1 to G5. Viewing auroras For best chances you should find a place with un-obscured views North and away from light pollution.
Good luck in your aurora chasing — Tony. Figure showing you where high and low geomagnetic latitudes are. The auroral zone corresponds to high geomagnetic latitudes where the aurora is the most frequent. Even during low geomagnetic activity, the aurora often dances in the sky at these latitudes. Just remember the Kiruna K index jumping to 5 typically meaning nice aurora whereas the global average was only 2! You typically need more powerful storms corresponding to a Kp of minimum 5 to start seeing some aurora on the horizon at lower geomagnetic latitudes in the sub-auroral zone.
Can I use the Kp for aurora chasing or forecasting? The short answer is NO. Despite popular belief, the Kp index is not a good source for aurora forecasting and nowcasting. There are several reasons why. First off, the observed Kp index has a three-hour time resolution. Now some services live-update on their website and social media accounts when thresholds are reached. If the effects of a storm are favorable for a long time, this can be used, especially if you are chasing at low.
However if you are chasing at higher geomagnetic latitudes, chances are bright aurora shows will have already passed before you get a Kp alert! Second off, there are several Kp indices that average different local K index stations. They will sometimes lead to significantly different numbers because of the number of K stations they average and where they are located. Therefore the Potsdam Kp is not very realistic for high latitudes mainly under Kp 5. Sometimes the different services will provide a Kp forecast for the next hour, 3 days or sometimes month!
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