Eddy covariance input data

Because roughly 70% of humanity’s atmospheric greenhouse gas (GHG) emissions are produced in urban areas, there is much interest in accurate and actionable quantification of urban emissions at the city scale. Emissions quantification can help to address high-level questions such as: • How large are my city’s emissions? • What are the main emissions sources in my city? • Are we on track to meet our emissions goals? • How much have our emissions decreased since implementing specific initiatives? • How can we demonstrate emissions mitigation successes? These distinct but related questions are relevant to a wide range of stakeholders across both the public and private sectors, such as city and national governments, the research community, educational institutions and non-governmental organizations. The good research practice guidelines presented in the present publication are intended for those seeking to answer these sorts of questions by using scientifically robust approaches to estimate urban GHG emissions. In recent decades, technological and methodological advances within the research community have led to the development of diverse approaches to emissions quantification. These approaches require varying intensities of investment in domains including initial instrument acquisition and setup, data collection infrastructure, ongoing expert involvement, ongoing maintenance and computational resources. These quantification approaches span a range of spatial and temporal resolutions, and each approach is suited to a particular subset of high-priority stakeholder questions and needs. These approaches are categorized into two main groups: “emission quantification tools” and “underlying input data”. Emission quantification tools range from traditional activity data-based approaches to quantification of fluxes using atmospheric observations and computational modelling. Underlying input data includes activity data, meteorological data and a suite of methods for atmospheric GHG observations. The present publication highlights case studies and examples of successful applications. The present guidelines are divided into two parts: (1) a concise first part to guide the making of links between high-level emissions questions (for example “are we on track toward our emissions goals”?) and appropriate methodologies; and (2) detailed technical chapters on each of the 31 emissions quantification approaches, to guide practitioners in bestpractice implementation. The guidelines focus primarily on carbon dioxide (CO2) and methane (CH4), because these are the most significant drivers of anthropogenic climate change. Many of the methods discussed are applicable to other GHGs including nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and nitrogen trifluoride (NF3). The gases SF6, HFCs, PFCs and NF3, which are classified as fluorinated GHGs, are commonly called Fgases or synthetic GHGs. This is the second iteration of these guidelines, and they are expected to be updated every few years.