Dry Deposition Methods Based on Turbulence Kinetic Energy: Part 1.
Evaluation of Various Resistances and Sensitivity Studies Using a
Single-Point Model
Abstract
Different functions are used to account for turbulence in the
atmospheric boundary layer for different stability regimes. These
functions are one of the sources for differences among different
atmospheric models’ predictions and associated biases. Also, turbulence
is underrepresented in some of the resistance formulations. To address
these issues with dry deposition, firstly we take advantage of
three-dimensional (3-D) aspects of turbulence in estimating resistances
by proposing and validating a 3-D turbulence velocity scale that is
relevant for different stability regimes of boundary layer. Secondly, we
hypothesize and prove that 3-D sonic anemometer measured friction
velocity, used in 0-D and 1-D models, can be effectively replaced by the
new turbulence velocity scale multiplied by the von Karman constant.
Finally, we (1) evaluate a set of resistance formulations for ozone
(O3), based on the 3-D turbulence velocity scale; and
(2) intercompare estimations of such resistances with those obtained
using the existing formulations and also evaluate simulated
O3 fluxes using a single-point dry deposition model
against long-term observations of O3 fluxes at the
Harvard Forest site. Results indicate that the new resistance
formulations work very well in simulating surface latent heat and
O3 fluxes when compared to respective existing
formulations as well as measurements at decadal time scale. Findings
from this research may help to improve the capability of dry deposition
schemes for better estimation of dry deposition fluxes and create
opportunities for the development of a community dry deposition model
for use in regional/global air quality models.