Spatial and Temporal Analysis of Carbon Dioxide Concentrations over Italy by means of OCO‑2 Satellite Data Series

Abstract

Carbon dioxide is a greenhouse gas with sink and source related to natural cycles and anthropic activities. OCO‑2 is a NASA carbon dioxide dedicated mission launched in 2014 aimed to measure the CO2 concentrations in the atmosphere by recording sunlight reflected off the Earth and provides, at the state of the art, the highest spatial resolution for mapping CO2 at global scale. In this work, for the first time, we statistically analyse 8 years of OCO‑2 acquisitions over Italian territory, obtaining the main trend and the seasonal behaviour of CO2 over land. After data reprocessing and compensating on temporal frequency of OCO‑2 acquisitions over Italy, a mean of 21 ppm of increment in the period from 2015 to 2022 has been found. In the data time series, we also noticed a significant acceleration in the trend between 2019 and 2020 and a return to average values of the trend after the COVID19 pandemic lockdown. In addition, such trends have been compared with those achieved by the European Centre for Medium Range Weather Forecasts (ECMWF) model. The data time series was also used to perform a spatial analysis of areas characterized by lower/higherc CO2 concentrations to detect sinks/sources in Italy due to the land use. The analysis reveals that the North Italian regions, with more population and industries, are the source of CO2; moreover, the fundamental role of vegetation as a sink of CO2 is confirmed.