Analysis of Saint-Petersburg`s CO2 anthropogenic emissions estimation by differential spectroscopy method

Needs in obtaining independent and high-quality information on anthropogenic emissions of important for climate and ecology gases led to the development of spectroscopic (ground-based and satellite) methods of the emission determination. This challenge can be reduced to two sequential inverse problems - the inverse problem of atmospheric optics and atmospheric transport. Here we studied the merits and disadvantages of differential IR methods for the emissions estimation. Also we investigated the main factors determining their errors such as:

• Quality and number of the observations of spatio-temporal distribution of gases studied
• Capabilities of the numerical models to simulate atmospheric transport
• Spatial and temporal resolutions of emissions estimated
• etc.

In the current study integral anthropogenic CO₂ emissions of Saint-Petersburg were determined using observation data of the city`s anthropogenic contribution to the gas content. In addition we implemented a new approach of inverse problem solution which was based on a priori CO<sub>2</sub> emission data and scale coefficients applied only to the city`s areas covered by the observations. Integral anthropogenic CO₂ emissions obtained were in a range from approximately 52 to 72 Mt/year. These emissions are significantly higher than inventory-based estimates which constitute ⁓30 Mt/year. Nevertheless, the minimal value of the range (~52 Mt/year) is lower by ~21% than emissions which we calculated earlier also using observations (~65 Mt/year).