Articles | Volume 7, issue 6
Geosci. Model Dev., 7, 2663–2681, 2014
Geosci. Model Dev., 7, 2663–2681, 2014

Development and technical paper 13 Nov 2014

Development and technical paper | 13 Nov 2014

Applicability of an integrated plume rise model for the dispersion from wild-land fires

J. Kukkonen1, J. Nikmo1, M. Sofiev1, K. Riikonen1, T. Petäjä2, A. Virkkula1,2, J. Levula3, S. Schobesberger2, and D. M. Webber4 J. Kukkonen et al.
  • 1Finnish Meteorological Institute, Erik Palménin aukio 1, 00101, Helsinki, Finland
  • 2Department of Physics, University of Helsinki, 00014, Helsinki, Finland
  • 3Hyytiälä Forestry Field Station, University of Helsinki, 35500, Korkeakoski, Finland
  • 4Integral Science and Software Ltd, 484 Warrington Rd, Culcheth, Warrington WA3 5RA, UK

Abstract. We have presented an overview of a mathematical model, BUOYANT, that was originally designed for the evaluation of the dispersion of buoyant plumes originated from major warehouse fires. The model addresses the variations of the cross-plume integrated properties of a buoyant plume in the presence of a vertically varying atmosphere. The model also includes a treatment for a rising buoyant plume interacting with an inversion layer. We have compared the model predictions with the data of two prescribed wild-land fire experiments. For the SCAR-C experiment in Quinault (US) in 1994, the predicted vertical extents of the plume at maximum plume rise were between 500 and 800 m and between 200 and 700 m, using two alternative meteorological data sets. The corresponding observed injection heights of the aerosol particles measured using an airborne lidar (light detection and ranging) ranged from 250 to 600 m. For the prescribed burning experiment in Hyytiälä (Finland) in 2009, the model predictions were compared with plume elevations and diameters, determined based on particulate matter number concentration measurements onboard an aeroplane. However, the agreement between modelled and measured results substantially depends on how the properties of the source term are evaluated, especially regarding the convective heat fluxes from the fire. The results demonstrate that in field experiments on wild-land fires, there are substantial uncertainties in estimating both (i) the source terms for the atmospheric dispersion computations and (ii) the relevant vertical meteorological profiles.