Document Type

Article

Publication Date

August 2017

Publication Title

Journal of Applied Meteorology and Climatology

Volume

56

Issue Number

8

First Page

2289

Last Page

2299

DOI

10.1175/JAMC-D-16-0384.1

Keywords

Convection, Entrainment, Updrafts, Forest fires, Wildfires

Disciplines

Climate | Meteorology | Other Oceanography and Atmospheric Sciences and Meteorology

Abstract

The time-mean and time-varying smoke and velocity structure of a wildfire convective plume is examined using a high-resolution scanning Doppler lidar. The mean plume is shown to exhibit the archetypal form of a bent-over plume in a crosswind, matching the well-established Briggs plume-rise equation. The plume cross section is approximately Gaussian and the plume radius increases linearly with height, consistent with plumerise theory. The Briggs plume-rise equation is subsequently inverted to estimate the mean fire-generated sensible heat flux, which is found to be 87 kW m22 . The mean radial velocity structure of the plume indicates flow convergence into the plume base and regions of both convective overshoot and sinking flow in the upper plume. The updraft speed in the lower plume is estimated to be 13.5 m s21 by tracking the leading edge of a convective element ascending through the plume. The lidar data also reveal aspects of entrainment processes during the plume rise. For example, the covariation of the radial velocity and smoke perturbations are shown to dilute the smoke concentration with height.

Comments

© 2017 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
This article was published in the Journal of Applied Meteorology and Climatology, volume 56, issue 8, 2017, and can be found online at the following link: https://doi.org/10.1175/JAMC-D-16-0384.1
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