Articles | Volume 9, issue 9
Geosci. Model Dev., 9, 3177–3197, 2016
Geosci. Model Dev., 9, 3177–3197, 2016

Development and technical paper 16 Sep 2016

Development and technical paper | 16 Sep 2016

Enhanced representation of soil NO emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

Quazi Z. Rasool1, Rui Zhang1, Benjamin Lash1,a, Daniel S. Cohan1, Ellen J. Cooter2, Jesse O. Bash2, and Lok N. Lamsal3,4 Quazi Z. Rasool et al.
  • 1Department of Civil and Environmental Engineering, Rice University, Houston, TX, USA
  • 2Computational Exposure Division, National Exposure Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC, USA
  • 3Goddard Earth Sciences Technology and Research, Universities Space Research Association, Columbia, MD 21046, USA
  • 4NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
  • anow at: School of Natural Sciences, University of California, Merced, CA, USA

Abstract. Modeling of soil nitric oxide (NO) emissions is highly uncertain and may misrepresent its spatial and temporal distribution. This study builds upon a recently introduced parameterization to improve the timing and spatial distribution of soil NO emission estimates in the Community Multiscale Air Quality (CMAQ) model. The parameterization considers soil parameters, meteorology, land use, and mineral nitrogen (N) availability to estimate NO emissions. We incorporate daily year-specific fertilizer data from the Environmental Policy Integrated Climate (EPIC) agricultural model to replace the annual generic data of the initial parameterization, and use a 12 km resolution soil biome map over the continental USA. CMAQ modeling for July 2011 shows slight differences in model performance in simulating fine particulate matter and ozone from Interagency Monitoring of Protected Visual Environments (IMPROVE) and Clean Air Status and Trends Network (CASTNET) sites and NO2 columns from Ozone Monitoring Instrument (OMI) satellite retrievals. We also simulate how the change in soil NO emissions scheme affects the expected O3 response to projected emissions reductions.

Short summary
This study updates the representation of soil NO emissions in a regional air quality model. The implementation enhances the representation of biome types and dynamic fertilizer use. Previous modeling of soil NO in CMAQ had tended to under-estimate emissions and misrepresent their response to soil conditions and meteorology. We evaluate results against satellite observations of NO2, and quantify the impacts of the new parameterization on simulations of ozone and particulate matter.