Characterization of the Advanced LIGO detectors during their first observing run

The Advanced LIGO gravitational wave detectors have recently completed their first observing run from September 2015 - January 2016. Characterization of non-astrophysical transient artifacts in the detectors is crucial to the mitigation of noise sources that contaminate the astrophysical gravitational wave transient searches as well as the interpretation of any candidate event identified by these algorithms. This talk addresses transient noise sources during the first Advanced LIGO observing run and summarizes techniques to monitor and mitigate their impact on the astrophysical searches.