Linking agricultural crop management and air quality models for regional to national-scale nitrogen assessments

Abstract

Abstract. While nitrogen (N) is an essential element for life, human population growth and demands for energy, transportation and food can lead to excess nitrogen in the environment. A modeling framework is described and implemented to promote a more integrated, process-based and systemlevel approach to the estimation of ammonia (NH 3 ) emissions which result from the application of inorganic nitrogen fertilizers to agricultural soils in the United States. The United States Department of Agriculture (USDA) Environmental Policy Integrated Climate (EPIC) model is used to simulate plant demand-driven fertilizer applications to commercial cropland throughout the continental US. This information is coupled with a process-based air quality model to produce continental-scale NH 3 emission estimates. Regional cropland NH 3 emissions are driven by the timing and amount of inorganic NH 3 fertilizer applied, soil processes, local meteorology, and ambient air concentrations. Initial fertilizer application often occurs when crops are planted. A statelevel evaluation of EPIC-simulated, cumulative planted area compares well with similar USDA reported estimates. EPICannual, inorganic fertilizer application amounts also agree well with reported spatial patterns produced by others, but domain-wide the EPIC values are biased about 6 % low. Preliminary application of the integrated fertilizer application and air quality modeling system produces a modified geospatial pattern of seasonal NH 3 emissions that improves current simulations of observed atmospheric particle nitrate concentrations. This modeling framework provides a more dynamic, flexible, and spatially and temporally resolved estimate of NH 3 emissions than previous factor-based NH 3 inventories, and will facilitate evaluation of alternative nitrogen and air quality policy and adaptation strategies associated with future climate and land use changes.

Online coupled regional meteorology chemistry models in Europe: current status and prospects

“…Advanced resistance models accounting for capacitance of leaf surfaces have been developed to simulate the bi-directional NH 3 exchange (e.g. Nemitz et al, 2001;Wu et al, 2009) and incorporated into WRF-CMAQ (Cooter et al, 2012;Bash et al, 2013 andPleim et al, 2013). Wichink Kruit et al (2012) showed that by including bi-directional exchange in the LOTOS-EUROS model, NH 3 concentrations increased almost everywhere in Europe and nitrogen deposition shifted away from agricultural areas towards large natural areas and remote regions.…”

Advances in understanding, models and parameterizations of biosphere-atmosphere ammonia exchange

“…local N deposition impacts assessments Theobald et al, 2004Theobald et al, , 2009Sutton et al, 1998b;, air quality studies (Pinder et al, 2007;Wu et al, 2008), and transboundary air pollution flux estimation Berge et al, 1999). Models of surface/atmosphere NH 3 exchange have been both developed and applied for a number of purposes and at a large range of spatial scales ranging from the leaf or plant (Massad et al, 2010a), the canopy or ecosystem (Sutton et al, 1998a;Nemitz et al, 2001a;Riedo et al, 2002;Personne et al, 2009), the landscape Hertel et al, 2006), to the national/regional level (van Pul et al, 2009; Biogeosciences, 10, 5183-5225, 2013 www.biogeosciences.net/10/5183/2013/ C. R. Flechard et al: Biosphere-atmosphere ammonia exchange 5185 Bash et al, 2012) and to the globe (Dentener and Crutzen, 1994). The objectives of the modelling depend on the spatial and temporal scales at which models are ultimately applied.…”

“…Elsewhere, earlier R c models have also been modified to include a surface NH 3 compensation point, such as: the surface exchange scheme within AURAMS (Zhang et al, 2003(Zhang et al, , 2010) with a 2-layer χ s /χ g /R w structure; the revision of the DEPAC model into DEPAC3.11 with a 1-layer χ s /χ w /R w structure (van Zanten et al, 2010;Wichink Kruit et al, 2010); a revised χ s /R w version of PLATIN (Grünhage and Haenel, 2008); or the inclusion of the 2-layer χ s /χ g /R w by Nemitz et al (2001a) into CMAQ for managed agricultural soils (Cooter et al, 2010(Cooter et al, , 2012Bash et al 2012) (see parameterization details below).…”

“…The model developed by Nemitz et al (2000a) Cooter et al, 2012;Williams et al, 2008), in which soil organic C and N are split into three compartments: microbial biomass, slow humus and passive humus, and organic residues added to the soil surface or belowground are split into metabolic and structural litter compartments as a function of C and N content. Following the CENTURY (Parton et al, 1994) approach, EPIC includes linear partition coefficients and soil water content to calculate movement as modified by sorption, which are used to move organic materials from surface litter to subsurface layers; temperature and water controls affecting transformation rates are calculated internally in EPIC; the surface litter fraction in EPIC has a slow compartment in addition to metabolic and structural litter components; while lignin concentration is simulated as an empirical sigmoidal function of plant age.…”

“…3.1), which was calibrated using data collected during an intensive 2007 maize field study in Lillington, North Carolina Walker et al, 2013). More recently, regional simulations of CMAQ coupled with EPIC have provided dynamic continental (US) scale NH 3 emission estimates from fertilizer applications with a tight coupling between emissions, deposition and agricultural cropping practices (Cooter et al, 2012;Bash et al, 2012) (see Sect. 3.4).…”