RT Journal Article
T1 Methods for interpolating missing data in aerobiological databases
A1 Picornell Rodríguez, Antonio
A1 Oteros, Jose
A1 Ruiz-Mata, Rocío
A1 Recio-Criado, María Marta
A1 Trigo-Pérez, María del Mar
A1 Martínez-Bracero, Moisés
A1 Lara, Beatriz
A1 Serrano-García, A.
A1 Galán, Carmen
A1 García-Mozo, Herminia
A1 Alcázar, Purificación
A1 Pérez-Badia, Rosa
A1 Cabezudo-Artero, Baltasar
A1 Romero-Morte, Jorge
A1 Rojo, Jesús
K1 Análisis de series temporales
AB The availability of extensive environmental time series is usually laborious and difficult, and sometimes unexpected failures are not detected until samples are processed. Consequently, environmental databases frequently have some gaps with missing data in it. Applying an interpolation method before starting the data analysis can be a good solution in order to complete this missing information. Nevertheless, there are several different approaches whose accuracy should be considered and compared. In this study, data from 6 aerobiological sampling stations were used as an example of environmental data series to assess the accuracy of different interpolation methods. For that, observed daily pollen/spore concentration data series were randomly removed, interpolated by using different methods and then, compared with the observed data to measure the errors produced. Different periods, gap sizes, interpolation methods and bioaerosols were considered in order to check their influence in the interpolation accuracy. The moving mean interpolation method obtained the highest success rate as average. By using this method, a success rate of the 70% was obtained when the risk classes used in the alert systems of the pollen information platforms were taken into account. In general, errors were mostly greater when there were high oscillations in the concentrations of biotic particles during consecutive days. That is the reason why the pre-peak and peak periods showed the highest interpolation errors. The errors were also higher when gaps longer than 5 days were considered. So, for completing long periods of missing data, it would be advisable to test other methodological approaches. A new Variation Index based on the behaviour of the pollen/spore season (measurement of the variability of the concentrations every 2 consecutive days) was elaborated, which allows to estimate the potential error before the interpolation is applied.
PB Elsevier
YR 2021
FD 2021-05-28
LK https://hdl.handle.net/10630/33729
UL https://hdl.handle.net/10630/33729
LA eng
NO Picornell, A., Oteros, J., Ruiz-Mata, R., Recio, M., Trigo, M.M., Martínez-Bracero, M., Lara, B., Serrano-García, A., Galán, C., García-Mozo, H., Alcázar, P., Pérez-Badia, R., Cabezudo, B., Romero-Morte, J., Rojo, J., 2021. Methods for interpolating missing data in aerobiological databases. Environ Res 200, 111391. https://doi.org/10.1016/j.envres.2021.111391
NO This work was supported by the Spanish Ministry of Economy and Competitiveness [project CGL2014-54731-R]; by the Ministry of Science and Innovation [projects RTI2018-096392-B-C22]; by the Junta de Andalucía [contract 8.06/503.4764]; and by the Area of Environment and Sustainability of the Malaga City Council [contracts 8.06/5.03.4721 and 8.07/5.03.5159], and the Junta Comunidades de Castilla-La Mancha, which provides financial support for the Castilla-La Mancha Aerobiology Network (AEROCAM). Antonio Picornell was supported by a predoctoral grant financed by the Spanish Ministry of Education, Culture and Sport, in the Program for the Promotion of Talent and its Employability [grant number FPU15/01668]. The pollen trap installed in Sierra de las Nieves was funded by the Herbarium MGC of the SCAI (Central Services of Research Support) of the University of Malaga under the agreement signed between the Junta de Andalucía and the University of Malaga [contract 8.07/5.034764].Acknowledgments: The authors specially want to thanks the SCAI (Central Service for Research Support) of the University of Malaga for supporting the acquisition of the pollen trap installed in Sierra de las Nieves; the Parauta City Council, the direction of Sierra de las Nieves Natural Park, Las Conejeras campsite for facilitating the installation of the pollen trap in Sierra de las Nieves; and the staff of Pérez de Guzmán High School for providing support to install and maintain the pollen trap in Ronda, and to Enresa for facilitating the installation and maintenance of the pollen trap in Hornachuelos Natural Park.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 20 ene 2026