Näytä suppeat kuvailutiedot

dc.contributor.authorHelske, Jouni
dc.contributor.authorNyblom, Jukka
dc.contributor.authorEkholm, Petri
dc.contributor.authorMeissner, Kristian
dc.date.accessioned2016-03-14T11:23:20Z
dc.date.available2016-03-14T11:23:20Z
dc.date.issued2013
dc.identifier.citationHelske, J., Nyblom, J., Ekholm, P., & Meissner, K. (2013). Estimating aggregated nutrient fluxes in four Finnish rivers via Gaussian state space models. <em>Environmetrics</em>, 24 (4), 237-247. <a href="http://dx.doi.org/10.1002/env.2204">doi:10.1002/env.2204</a>
dc.identifier.otherTUTKAID_56960
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/49047
dc.description.abstractReliable estimates of the nutrient fluxes carried by rivers from land-based sources to the sea are needed for efficient abatement of marine eutrophication. Although nutrient concentrations in rivers generally display large temporal variation, sampling and analysis for nutrients, unlike flow measurements, are rarely performed on a daily basis. The infrequent data calls for ways to reliably estimate the nutrient concentrations of the missing days. Here, we use the Gaussian state space models with daily water flow as a predictor variable to predict missing nutrient concentrations for four agriculturally impacted Finnish rivers. Via simulation of Gaussian state space models, we are able to estimate aggregated yearly phosphorus and nitrogen fluxes, and their confidence intervals. The effect of model uncertainty is evaluated through a Monte Carlo experiment, where randomly selected sets of nutrient measurements are removed and then predicted by the remaining values together with re-estimated parameters. Results show that our model performs well for rivers with long-term records of flow. Finally, despite the drastic decreases in nutrient loads on the agricultural catchments of the rivers over the last 25 years, we observe no corresponding trends in riverine nutrient fluxes.
dc.language.isoeng
dc.publisherWiley-Blackwell
dc.relation.ispartofseriesEnvironmetrics
dc.subject.othersimulointi
dc.subject.otherharva aineisto
dc.subject.otherinterpolointi
dc.subject.otherKalmanin suodin
dc.subject.otherKalmanin tasoitin
dc.subject.othersimulation
dc.subject.othersparse data
dc.subject.otherinterpolation
dc.subject.otherKalman filter
dc.subject.otherKalman smoother
dc.titleEstimating aggregated nutrient fluxes in four Finnish rivers via Gaussian state space models
dc.typearticle
dc.identifier.urnURN:NBN:fi:jyu-201603141838
dc.contributor.laitosMatematiikan ja tilastotieteen laitosfi
dc.contributor.laitosDepartment of Mathematics and Statisticsen
dc.contributor.oppiaineTilastotiede
dc.type.urihttp://purl.org/eprint/type/SubmittedJournalArticle
dc.date.updated2016-03-14T10:15:08Z
dc.type.coarjournal article
dc.description.reviewstatuspeerReviewed
dc.format.pagerange237-247
dc.relation.issn1099-095X
dc.relation.volume24
dc.type.versionacceptedVersion
dc.rights.copyright© 2013 John Wiley & Sons, Ltd. This is a final draft version of an article whose final and definitive version has been published by John Wiley & Sons.
dc.rights.accesslevelopenAccessfi
dc.relation.doi10.1002/env.2204


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Näytä suppeat kuvailutiedot