An application programming interface (API) isa form of interface that allows applications to access the features or dataof an operating system, application, or other service. An API may have arequired
protocol or set of principles. Some examples of protocols are SOAP,XML-RPC and JSON-RPC. An example of an API with a set of principles is REST.
A mean, 3-hourly ”equivalent amplitude” of magnetic activity based on K index data from a planetary network of 11 Northern and 2 Southern Hemisphere magnetic observatories between the geomagnetic lati
tudes of 46° and 6° by the lnstitut fur Geophysik at Gottingen, Germany; ap values are given in units of 2 nT.
Formally determined from the eight daily ap indices. However, for daily operational uses, NOAA/SWPC estimates the value of the Ap index by measuring the geomagnetic field in near-real time at several
magnetometer stations around the world. The real-time station indices are used to estimate the official Kp and Ap based on historical data. The value of this estimated Ap index is reported in NOAA daily and weekly summaries of geophysical activity.