A multi-city urban atmospheric greenhouse gas measurement data synthesis

Abstract

Urban regions emit a large fraction of anthropogenic emissions of greenhouse gases (GHG) such as carbon dioxide (CO₂) and methane (CH₄) that contribute to modern-day climate change. As such, a growing number of urban policymakers and stakeholders are adopting emission reduction targets and implementing policies to reach those targets. Over the past two decades research teams have established urban GHG monitoring networks to determine how much, where, and why a particular city emits GHGs, and to track changes in emissions over time. Coordination among these efforts has been limited, restricting the scope of analyses and insights. Here we present a harmonized data set synthesizing urban GHG observations from cities with monitoring networks across North America that will facilitate cross-city analyses and address scientific questions that are difficult to address in isolation.

Fig. 1

Schematic of the CO₂-USA project. The map shows the eight cities currently in the CO2-USA network (there are two measurement networks in San Francisco). (a) Workshops were held to determine community, stakeholder and policymaker needs. (b) This paper describes the harmonized multi-city dataset of atmospheric CO₂, CH₄ and CO. (c) Inventories of biospheric and anthropogenic emissions were created. (d) Updates were made to atmospheric models. (e) All of these components can be used together to create estimates of urban carbon emissions using inverse analyses. (f) These results can be presented to the community, stakeholders, and policymakers.

Fig. 2

Time series of the CO₂-USA data synthesis data set. The columns show CO₂ (left), CH₄ (middle), and CO (right) while the rows show the CO₂-USA cities in alphabetical order. Each colored line represents an inlet at a site while the thicker black lines are the background mole fractions (shown for species/cities where a published background is available). BAAQMD: Bay Area Air Quality Management District. BEACO₂N: Berkeley Environmental Air-quality & CO₂ Network.

Fig. 3

The number of inlets and measurement sites in each city in the CO₂-USA network over time. BAAQMD: Bay Area Air Quality Management District. BEACO₂N: Berkeley Environmental Air-quality & CO₂ Network.