A21H-0249
Modelling urban δ13C variations in the Greater Toronto Area
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Stephanie Pugliese1, Felix R Vogel2, Jennifer G Murphy3, Doug E. J. Worthy4, Junhua Zhang5, Qiong Zheng4 and Michael D Moran5, (1)University of Toronto, Toronto, ON, Canada, (2)LSCE Laboratoire des Sciences du Climat et de l'Environnement, Gif-Sur-Yvette Cedex, France, (3)University of Toronto, Chemistry, Toronto, ON, Canada, (4)Environment Canada, Toronto, Canada, (5)Environment Canada Toronto, Toronto, ON, Canada
Abstract:
Even in urbanized regions, carbon dioxide (CO2) emissions are derived from a variety of biogenic and anthropogenic sources and are influenced by atmospheric transport across borders. As policies are introduced to reduce the emission of CO2, there is a need for independent verification of emissions reporting. In this work, we aim to use carbon isotope (13CO2 and 12CO2) simulations in combination with atmospheric measurements to distinguish between CO2 sources in the Greater Toronto Area (GTA), Canada. This is being done by developing an urban δ13C framework based on existing CO2 emission data and forward modelling using a chemistry transport model, CHIMERE. The framework is designed to use region specific δ13C signatures of the dominant CO2 sources together with a CO2 inventory at a fine spatial and temporal resolution; the product is compared against highly accurate 13CO2 and 12CO2 ambient data. The strength of this framework is its potential to estimate both locally produced and regionally transported CO2. Locally, anthropogenic CO2 in urban areas is often derived from natural gas combustion (for heating) and gasoline/diesel combustion (for transportation); the isotopic signatures of these processes are significantly different (approximately d13CVPDB = -40 ‰ and -26 ‰ respectively) and can be used to infer their relative contributions. Furthermore, the contribution of transported CO2 can also be estimated as nearby regions often rely on other sources of heating (e.g. coal combustion), which has a very different signature (approximately d13CVPDB = -23 ‰). We present an analysis of the GTA in contrast to Paris, France where atmospheric observations are also available and 13CO2 has been studied. Utilizing our δ13C framework and differences in sectoral isotopic signatures, we quantify the relative contribution of CO2 sources on the overall measured concentration and assess the ability of this framework as a tool for tracing the evolution of sector-specific emissions.
