caa a22 4500 445874457 CHVBK 20180317145523.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s10652-010-9194-8 doi (NATIONALLICENCE)springer-10.1007/s10652-010-9194-8 Concentration fluctuations in a downtown urban area. Part I: analysis of Joint Urban 2003 full-scale fast-response measurements [Elektronische Daten] [P. Klein, Duick Young] Statistics are investigated for concentration time series measured with fast-response analyzers during the Joint Urban 2003 experiment in Oklahoma City. Data collected at nine different sites for a total of six 30-min continuous releases were analyzed. After a short description of the measurements and meteorological conditions prevailing during the two chosen intensive observation periods, the variation of mean concentrations, fluctuation intensity, peak-to-mean ratio, concentration percentiles, and intermittency are discussed. High intermittency is only observed at sites close to the edge of the urban plumes. Even though the meteorological conditions during all six releases were quite similar, all concentration parameters generally show great variability. This highlights the difficulty of obtaining representative statistics from full-scale experiments, during which only relatively short time series can be recorded and diurnal variations of weather patterns are typical. In addition to the concentration statistics, the measured cumulative probability (CDF) and exceedance probablity (EDF) functions are compared with two-parametric gamma and 3-parametric clipped-gamma CDFs and EDFs. It can be shown that both gamma distributions agree well with the observations particularly in the upper tail of the distributions, and that realistic 95 and 98 concentration percentiles are predicted for plumes dispersing in an urban environment. The clipped-gamma distribution, which better captures important dispersion physics, performs slightly better for highly intermittent signals but its performance depends on which relationship between intermittency and fluctuation intensity is assumed, and is thus not necessarily a better choice for practical applications. The issues of limited statistical representativeness of the analyzed data is further addressed in a second part of this paper which includes the analysis of wind-tunnel concentration time series. Springer Science+Business Media B.V., 2010 Atmospheric dispersion nationallicence Concentration fluctuations nationallicence Peak concentrations nationallicence Urban air quality nationallicence Klein P. School of Meteorology, University of Oklahoma, 120 David L. Boren Blvd., 73072, Norman, OK, USA aut Young Duick King's College London, London, UK aut Environmental Fluid Mechanics Springer Netherlands 11/1(2011-02-01), 23-42 1567-7419 11:1<23 2011 11 10652 https://doi.org/10.1007/s10652-010-9194-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10652-010-9194-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Klein P. School of Meteorology, University of Oklahoma, 120 David L. Boren Blvd., 73072, Norman, OK, USA aut NATIONALLICENCE 700 1- Young Duick King's College London, London, UK aut NATIONALLICENCE 773 0- Environmental Fluid Mechanics Springer Netherlands 11/1(2011-02-01), 23-42 1567-7419 11:1<23 2011 11 10652 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer