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The Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory(SDO) returns high-resolution images of the solar atmosphere in seven extremeultraviolet (EUV) wavelength channels. The images are processed on the groundto remove intensity spikes arising from energetic particles hitting theinstrument, and the despiked images are provided to the community. In thisarticle a three-hour series of images from the 171 A channel obtained on 28February 2017 was studied to investigate how often the despiking algorithm gavefalse positives caused by compact brightenings in the solar atmosphere. Thelatter were identified through spikes appearing in the same detector pixel forthree consecutive frames. 1096 examples were found from the 900 image frames.These "three-spikes" were assigned to 126 dynamic solar features, and it isestimated that the three-spike method identifies 20% of the total number offeatures affected by despiking. For any ten-minute sequence of AIA 171 A imagesthere are therefore around 35 solar features that have their intensity modifiedby despiking. The features are found in active regions, quiet Sun, and coronalholes and, in relation to solar surface area, there is a greater proportionwithin coronal holes. In 96% of the cases, the despiked structure is a compactbrightening of size two arcsec or less and the remaining 4% have narrow,elongated structures. By applying an EUV burst detection algorithm, we foundthat 96% of the events could be classed as EUV bursts. None of the spike eventsare} rendered invisible by the AIA processing pipeline, but the total intensityover an event's lifetime can be reduced by up to 67%. Users are recommended toalways restore the original intensities to AIA data when studying short-livedor rapidly evolving features that exhibit fine-scale structure.

An Analysis of Spikes in Atmospheric Imaging Assembly (AIA) Data