  Sources of geophysical noise (such as wind, sea waves and earthquakes) or of
anthropogenic noise (nearby activities, road traffic, etc.) impact ground-based
gravitational-wave (GW) interferometric detectors, causing transient
sensitivity worsening and gaps in data taking. During the one year-long third
Observing Run (O3: from April 01, 2019 to March 27, 2020), the Virgo
Collaboration collected a large dataset, which has been used to study the
response of the Advanced Virgo detector to a variety of environmental
conditions. We correlated environmental parameters to global detector
performance, such as observation range (the live distance up to which a given
GW source could be detected), duty cycle and control losses (losses of the
global working point, the instrument configuration needed to observe the
cosmos). Where possible, we identified weaknesses in the detector that will be
used to elaborate strategies in order to improve Virgo robustness against
external disturbances for the next data taking period, O4, currently planned to
start in March 2023. The lessons learned could also provide useful insights for
the design of the next generation of ground-based interferometers.
