Identification of air quality redundant stations through a clustering ensemble method

T Stolz,M Huertas,A Mendoza

doi:10.1088/1755-1315/489/1/012019

Abstract

The main purpose of this study is to assess the performance of three air quality monitoring networks of Mexico. Emphasis is placed on an ensemble method to combine the results of the different clustering techniques: Principle Component Analysis, Hierarchical Clustering and k-means. The specific objectives of this paper are: (i) finding similar and redundant stations using the ensemble method and (ii) giving a physical meaning to groups of similar stations by evaluating additional information like emission sources, meteorology and topography of the area of interest. The study was applied on time series data of particulates that have aerodynamic diameters less than or equal to 10 μm (PM10) and ozone (O3), acquired from the air pollutant monitoring systems in the metropolitan areas of Mexico City (MCMA), Monterrey (MMA) and Guadalajara (GMA). These three conurbations are characterized by diverse meteorological and geographical conditions. The findings show that the GMA has a well distributed air quality network with the fewest number of similar stations. The MMA presents the same clusters of stations for PM10 and O3, while in the MCMA a cluster of possible redundant stations is found. Results confirm that the clustering ensemble method is a confidence tool to identify similar stations.

Highlights

Accretionary wedge systems result from scraping of clastic sedimentary sequences off a descending oceanic plate at active subduction zones (Morley et al, 2011)
Numerical experiments with a visco-elasto-plastic rheology are applied to test the importance of backstop geometry, flexural rigidity, décollement strength, and surface erosion on the structural evolution of accretionary wedges undergoing different modes of sediment accretion, where underplating is introduced by the implementation of two, a basal and an intermediate, décollement levels
I present eleven experiments that were conducted to test the effects of backstop geometry, flexural rigidity of the oceanic lithosphere, décollement strength, and surface erosion on the structural evolution of accretionary wedge systems involving underplating

Summary

Introduction

Accretionary wedge systems result from scraping of clastic sedimentary sequences off a descending oceanic plate at active subduction zones (Morley et al, 2011). Sediments covering the incoming, subducting oceanic plate may be accreted at the wedge front, forming typical imbricate fans (Fig. 1A). On the other hand, buried parts of the stratigraphic sequence may underthrust the wedge body and subsequently accrete (underplate) at its base (Fig. 1A). Underplating may occur deeper in subduction zones and concern rocks other than sedimentary rocks, i.e., during basal accretion of continental basement or slicing of oceanic crust along the subduction interface (Angiboust et al, 2014; Calvert et al, 2006; Ruh et al, 2015). Underplating in accretionary wedges has been intensively investigated during the past four decades.

Methods

Results

Discussion

Conclusion