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Abstract:
Global geomagnetic indices are extensively used not only to characterize the geomagnetic disturbance level but also, e.g., for the parameterization of physical and empirical models of the near-Earth space environment and in data (re)analysis. One of the most utilized indices are Kp and Kp-related ap, Ap, Cp, and C9 indices derived and disseminated by the GFZ German Research Centre for Geosciences. Kp is extensively used for scientific and operational purposes and has proven to be a significant and reliable index. But still, Kp has two essential limitations, the temporal resolution (three-hourly interval) and the upper limit of 9 (geomagnetic activity is not accurately represented under extremely disturbed conditions).
We developed the new open-ended, high-cadence, Kp-like, global geomagnetic Hpo index family (half-hourly Hp30, hourly Hp60 and linearly scaled ap30, ap60 indices) that overcomes these limitations. These Hpo indices are based on the same 13 geomagnetic observatory data as Kp and are designed to represent planetary geomagnetic activity similarly to Kp but with higher time resolution and without an upper limit. The near real-time Hpo indices and their values back to 1995 are available for download at https://kp.gfz-potsdam.de/en/hp30-hp60/data.
Here, we present a comparison of local indices K and H30 and H60 as well as recent studies that used Hpo indices and a comparison of Hpo with hemispheric power, which is an important input to thermosphere-ionosphere models. Also, we analyse the Kp, Hp60 and Hp30 indices for the strongest geomagnetic storms over a several-day interval according to the minimum value of the Dst index.
