The geomagnetic Hpo index is a Kp-like index with a time resolution of half an hour, called Hp30, and one hour, called Hp60. besides that, the Hpo index is not capped at 9 like Kp, but is an open ended index that describes the strongest geomagnetic storms more nuanced than the three-hourly Kp, which is limited to the maximum value of 9. Next to the Hpo we also provide the linear apo index (ap30 and ap60). The Hpo index was developed in the H2020 project SWAMI and is described in Yamazaki et al (2022). The newest version Hpo V3.0 is described in this preprint. It is based on an improved algorithm for very high Hpo values and extends the time series back to January 1985
GFZ also offers an Hpo-prediction.