Microclimate Monitoring in the Carcer Tullianum: Temporal and Spatial Gradients Evidenced by Multivariate Analysis; First Campaign

For the exploration and study of a hypogean site priority should be given to microclimate monitoring, even before starting any excavation activity. Except for fortuitous findings during the planning of excavations, recoveries, restoration and conservation monitoring of chemical and physical microclimate parameters (e.g. temperature, relative humidity, light irradiance, concentrations of CO2, CO, O3, SOx, NOx, VOC, etc.) is desirable in order to identify their spontaneous values. Generally few sensors, sometimes only one, are applied and time series obtained, which are then analysed by means of control cards and/or univariate graphs. Contrarily in this study 15 cheap but accurate dataloggers were applied (Fig.1) for monitoring three environmental parameters every 5 minutes along a vertical axis between two environments on the ground floor and the basement (6 sensor points), along a horizontal axis in the ground floor room (3 sensor points) and in the basement along a vertical (6 sensor points) and a horizontal axis (2 sensor points). In the basement concentrations of CO, CO2 and O2 were measured and the two environments were not entered during the 15 days measurement campaign. Multivariate analysis aims to study the interaction with the external environment and to identify mutual variations of parameters and gradients in space and time.