{"HAPI":"3.3.1","status":{"code":1200,"message":"OK"},"startDate":"1932-01-01T12:00:00Z","stopDate":"2026-09-14T19:00:00Z","cadence":"P1D","timeStampLocation":"center","modificationDate":"2026-09-14T10:35:02Z","title":"Ap Index (Best Available, daily)","description":"Daily planetary geomagnetic index Ap: the arithmetic mean of the eight 3-hourly ap values of the UT day (unit: 2 nT), derived from the Kp index (introduced by Bartels, 1949, and endorsed by IAGA; based on K-values recorded at 13 geomagnetic observatories). Produced by GFZ Potsdam, redistributed by WDC for Geomagnetism, Kyoto. Best Available version: highest processing level per period (currently definitive only). Timestamps are bin centers of the UT day (12:00 UT; timeStampLocation=center).","resourceID":"doi:10.5880/Kp.0001","datasetCitation":"Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O., & Morschhauser, A. (2021). The Geomagnetic Kp Index and Derived Indices of Geomagnetic Activity. Space Weather, 19, e2020SW002641. doi:10.1029/2020SW002641. Kp index data: Matzka, J., Bronkalla, O., Tornow, K., Elger, K., & Stolle, C. (2021), Geomagnetic Kp index, V. 1.0, GFZ Data Services, doi:10.5880/Kp.0001. Redistributed via WDC for Geomagnetism, Kyoto.","licenseURL":"https://creativecommons.org/licenses/by/4.0/","parameters":[{"name":"Time","type":"isotime","units":"UTC","fill":null,"length":24,"label":"Time"},{"name":"apValue","type":"integer","units":null,"fill":"999","label":"Ap","description":"Daily equivalent planetary amplitude (unit: 2 nT); mean of the eight 3-hourly ap values."},{"name":"versionCode","type":"integer","units":null,"fill":null,"label":"Version Code","description":"Processing status code Mm (major*10+minor). Currently a single definitive version (versionCode 20)."}]}