Evaluating transport in the WRF model along the California coast 1Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0244, USA
19 Feb 2013
2Atmospheric, Earth, and Energy Division; Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA94550, USA
Received: 18 Jun 2012 – Published in Atmos. Chem. Phys. Discuss.: 10 Jul 2012 Abstract. This paper presents a step in the development of a top-down method to
complement the bottom-up inventories of halocarbon emissions in California
using high frequency observations, forward simulations and inverse methods.
The Scripps Institution of Oceanography high-frequency atmospheric
halocarbons measurement sites are located along the California coast and
therefore the evaluation of transport in the chosen Weather Research Forecast
(WRF) model at these sites is crucial for inverse modeling. The performance
of the transport model has been investigated by comparing the wind direction
and speed and temperature at four locations using aircraft weather reports as
well at all METAR weather stations in our domain for hourly variations.
Different planetary boundary layer (PBL) schemes, horizontal resolutions
(achieved through nesting) and two meteorological datasets have been tested.
Finally, simulated concentration of an inert tracer has been briefly
investigated. All the PBL schemes present similar results that generally
agree with observations, except in summer when the model sea breeze is too
strong. At the coarse 12 km resolution, using ERA-interim (ECMWF
Re-Analysis) as initial and boundary conditions leads to improvements
compared to using the North American Model (NAM) dataset. Adding higher
resolution nests also improves the match with the observations. However, no
further improvement is observed from increasing the nest resolution from 4 km
to 0.8 km. Once optimized, the model is able to reproduce tracer
measurements during typical winter California large-scale events (Santa Ana).
Furthermore, with the WRF/CHEM chemistry module and the European Database for
Global Atmospheric Research (EDGAR) version 4.1 emissions for HFC-134a, we
find that using a simple emission scaling factor is not sufficient to infer
emissions, which highlights the need for more complex inversions.
Revised: 22 Dec 2012 – Accepted: 08 Feb 2013 – Published: 19 Feb 2013
Citation: Yver, C. E., Graven, H. D., Lucas, D. D., Cameron-Smith, P. J., Keeling, R. F., and Weiss, R. F.: Evaluating transport in the WRF model along the California coast, Atmos. Chem. Phys., 13, 1837-1852, doi:10.5194/acp-13-1837-2013, 2013.