Home  /  Atmosphere  /  Vol: 8 Núm: 5 Par: May (2017)  /  Article

Optimizing the Spatial Resolution for Urban CO2 Flux Studies Using the Shannon Entropy


The ‘Hestia Project’ uses a bottom-up approach to quantify fossil fuel CO2 (FFCO2) emissions spatially at the building/street level and temporally at the hourly level. Hestia FFCO2 emissions are provided in the form of a group of sector-specific vector layers with point, line, and polygon sources to support carbon cycle science and climate policy. Application to carbon cycle science, in particular, requires regular gridded data in order to link surface carbon fluxes to atmospheric transport models. However, the heterogeneity and complexity of FFCO2 sources within regular grids is sensitive to spatial resolution. From the perspective of a data provider, we need to find a balance between resolution and data volume so that the gridded data product retains the maximum amount of information content while maintaining an efficient data volume. The Shannon entropy determines the minimum bits that are needed to encode an information source and can serve as a metric for the effective information content. In this paper, we present an analysis of the Shannon entropy of gridded FFCO2 emissions with varying resolutions in four Hestia study areas, and find: (1) the Shannon entropy increases with smaller grid resolution until it reaches a maximum value (the max-entropy resolution); (2) total emissions (the sum of several sector-specific emission fields) show a finer max-entropy resolution than each of the sector-specific fields; (3) the residential emissions show a finer max-entropy resolution than the commercial emissions; (4) the max-entropy resolution of the onroad emissions grid is closely correlated to the density of the road network. These findings suggest that the Shannon entropy can detect the information effectiveness of the spatial resolution of gridded FFCO2 emissions. Hence, the resolution-entropy relationship can be used to assist in determining an appropriate spatial resolution for urban CO2 flux studies. We conclude that the optimal spatial resolution for providing Hestia total FFCO2 emissions products is centered around 100 m, at which the FFCO2 emissions data can not only fully meet the requirement of urban flux integration, but also be effectively used in understanding the relationships between FFCO2 emissions and various social-economic variables at the U.S. census block group level.

 Articles related

Kuang Xiao, Yuku Wang, Guang Wu, Bin Fu and Yuanyuan Zhu    

Most cities in China are experiencing severe air pollution due to rapid economic development and accelerated urbanization. Long-term air pollution data with high temporal and spatial resolutions are needed to support research into physical and chemical p... see more

Revista: Atmosphere

Francesca Costabile, Honey Alas, Michaela Aufderheide, Pasquale Avino, Fulvio Amato, Stefania Argentini, Francesca Barnaba, Massimo Berico, Vera Bernardoni, Riccardo Biondi, Giampietro Casasanta, Spartaco Ciampichetti, Giulia Calzolai, Silvia Canepari, Alessandro Conidi, Eugenia Cordelli, Antonio Di Ianni, Luca Di Liberto, Maria Cristina Facchini, Andrea Facci, Daniele Frasca, Stefania Gilardoni, Maria Giuseppa Grollino, Maurizio Gualtieri, Franco Lucarelli, Antonella Malaguti, Maurizio Manigrasso, Mauro Montagnoli, Silvia Nava, Cinzia Perrino, Elio Padoan, Igor Petenko, Xavier Querol, Giulia Simonetti, Giovanna Tranfo, Stefano Ubertini, Gianluigi Valli, Sara Valentini, Roberta Vecchi, Francesca Volpi, Kay Weinhold, Alfred Wiedensohler, Gabriele Zanini, Gian Paolo Gobbi and Ettore Petralia    

In February 2017 the “Carbonaceous Aerosol in Rome and Environs (CARE)” experiment was carried out in downtown Rome to address the following specific questions: what is the color, size, composition, and toxicity of the carbonaceous aerosol in the Mediter... see more

Revista: Atmosphere

Clare Paton-Walsh, Élise-Andrée Guérette, Kathryn Emmerson, Martin Cope, Dagmar Kubistin, Ruhi Humphries, Stephen Wilson, Rebecca Buchholz, Nicholas B. Jones, David W. T. Griffith, Doreena Dominick, Ian Galbally, Melita Keywood, Sarah Lawson, James Harnwell, Jason Ward, Alan Griffiths and Scott Chambers    

We present findings from the Measurements of Urban, Marine and Biogenic Air (MUMBA) campaign, which took place in the coastal city of Wollongong in New South Wales, Australia. We focus on a few key air quality indicators, along with a comparison to regio... see more

Revista: Atmosphere