Hourly nowcast ap60 index

Hourly (60-minute ap-like) sub-auroral geomagnetic activity indicator provided by GFZ Potsdam, Germany. The near real-time computation is based on 1-minute geomagnetic data from the contributing observatories. The quiet magnetic field is subtracted and the remaining disturbance is translated into H60 value. The H60 values are standardized at each observatory to obtain Hs60 values, from which Hp60 value is derived as a mean. The ap60 index is obtained as a linear scale representation of Hp60 according to a mapping table.