Parameterization of gaseous dry deposition in atmospheric chemistry models: Sensitivity to aerodynamic resistance formulations under statically stable conditions (original) (raw)
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Journal of Geophysical Research, 1995
A dry deposition scheme has been developed for the chemistry general circulation model to improve the description of the removal of chemically reactive trace gases at the earth's surface. The chemistry scheme simulates background CH4-CO-NO x-HOx photochemistry and calculates concentrations of, for example, HNO3, NO•, and 0 3. A resistance analog is used to parameterize the dry deposition velocity for these gases. The aerodynamic resistance is calculated from the model boundary layer stability, wind speed, and surface roughness, and a quasi-laminar boundary layer resistance is incorporated. The stomatal resistance is explicitly calculated and combined with representative cuticle and mesophy|| resistances for each trace gas. The new scheme contributes to internal consistency in the model, in particular with respect to diurnal and seasonal cycles in both the chemistry and the planetary boundary layer processes and surface characteristics that control dry deposition. Evaluation of the model indicates satisfactory agreement between calculated and observed deposition velocities. Comparison of the results with model simulations in which the deposition velocity was kept constant indicates significant relative differences in deposition fluxes and surface layer trace gas concentrations up to about _+35%. Shortcomings are discussed, for example, violation of the constant flux approach for the surface layer, the lacking canopy description, and effects of surface water layers. 20,999 21,000 GANZEVELD AND LELIEVELD: DRY DEPOSITION PARAMETERIZATION IN CHEMISTRY GCM
A revised parameterization for gaseous dry deposition in air
Atmospheric …, 2003
A parameterization scheme for calculating gaseous dry deposition velocities in air-quality models is revised based on recent study results on non-stomatal uptake of O 3 and SO 2 over 5 different vegetation types. Non-stomatal resistance, which includes in-canopy aerodynamic, soil and cuticle resistances, for SO 2 and O 3 is parameterized as a function of friction velocity, relative humidity, leaf area index, and canopy wetness. Non-stomatal resistance for other chemical species is scaled to those of SO 2 and O 3 based on their chemical and physical characteristics. Stomatal resistance is calculated using a two-big-leaf stomatal resistance sub-model for all gaseous species of interest. The improvements in the present model compared to its earlier version include a newly developed non-stomatal resistance formulation, a realistic treatment of cuticle and ground resistance in winter, and the handling of seasonally-dependent input parameters. Model evaluation shows that the revised parameterization can provide more realistic deposition velocities for both O 3 and SO 2 , especially for wet canopies. Example model output shows that the parameterization provides reasonable estimates of dry deposition velocities for different gaseous species, land types and diurnal and seasonal variations. Maximum deposition velocities from model output are close to reported measurement values for different land types. The current parameterization can be easily adopted into different air-quality models that require inclusion of dry deposition processes.
A revised parameterization for gaseous dry deposition in air-quality models
Atmospheric Chemistry and Physics, 2003
A parameterization scheme for calculating gaseous dry deposition velocities in airquality models is revised based on recent study results on non-stomatal uptake of O 3 and SO 2 over 5 different vegetation types. Non-stomatal resistance, which includes in-canopy aerodynamic resistance, soil resistance and cuticle resistance, for SO 2 and O 3 is parameterized as a function of friction velocity, relative humidity, leaf area index, and canopy wetness. Non-stomatal resistance for all other species is scaled to those of SO 2 and O 3 based on their chemical and physical characteristics. Stomatal resistance is calculated using a leaf-stomatal-resistance model for all gaseous species of interest. The improvements in the present model compared to its earlier version include a newly developed non-stomatal resistance formulation, a realistic treatment of cuticle and ground resistance in winter and the handling of seasonally-dependent input parameters. Model evaluation shows that the revised parameterization can provide more realistic deposition velocities for both O 3 and SO 2 , especially for wet canopies. Example model output shows that the parameterization provides reasonable estimates of dry deposition velocities for different gaseous species, land types and diurnal and seasonal variations. Maximum deposition velocities from model output are close to reported measurement values for different land types. The current parameterization can be easily adopted into different air-quality models that require inclusion of dry deposition processes.
Dry deposition by an atmospheric model with horizontal subgrid
2016
Two modules have been developed which qualify mesoscale atmospheric models for simulating the chemical transport at resolutions much higher than the model grid. Compared with total fine-grid application this method proves to be nearly so efficient but more economic. The modules solve the chemical transport equations (a) and submit the horizontal subgrid (b) for the meteorological and chemical calculations: (a) The chemical transport module considers the triad NO-N02-03 together with a simplified hydrocarbon chemistry. Involved are chemical reactions, anthropogenic and biogenic emission, dry deposition, passive transport, and turbulent diffusion. For these calculations a special vertical subgrid was introduced within the lowest atmospheric model layer. lt eliminates the frequently used approach of constant vertical particle fluxes near the surface. (b) The horizontal-subgrid module splits the horizontal model grid equidistantly into subgrid cells. The vertical surface fluxes of momen...
A numerical method for determining the dry deposition of atmospheric trace gases
Boundary-Layer Meteorology, 1989
A diagnostic deposition model based on generally accepted micrometeorological ideas on the transfer of momentum, sensible heat and matter near the Earth's surface is presented. The parameterization of fluxes is based on the flux-gradient relationships in the turbulent region of the surface layer and the sublayer Stanton number as well as the Reynolds analogy between concentration , temperature and wind velocity distributions in the underlying sublayer. The model requires only vertical profile data of wind velocity, dry-and wet-bulb temperatures and trace gas concentrations from the turbulent part of the surface layer. The method has been applied to vertical profile data collected in field experiments such as the GREIV I 1974 project and the Great Plains Turbulence Project. In order to illustrate the way in which the model can be used to evaluate deposition fluxes and velocities of reactive trace gases, it has been applied to observed concentrations of NO, NO, and ozone.
Numerical Investigations Of The Dry Deposition Of Reactive Trace Gases
1970
Results from numerical investigations regarding the dry deposition of reactive trace gases like NO, NO2, and Og are presented. The investigations were carried out with a numerical model of the atmospheric boundary layer, which simulates the meteorological and photochemical processes as well as the heat and moisture transport processes within the vegetation-soil system as a function of height (depth) and time. The model is briefly described here. The model results show that the dry deposition fluxes of reactive trace gases are not only influenced by meteorological and plant-physiological parameters, but also by chemical reactions. In most cases, the trace gas fluxes vary strongly with height and often even show a change in the direction. The fluxes differ considerably from those obtained with the widely used 'big leaf multiple resistance approach. Hence, the constant flux approximation, on which this resistance approach is based, seems to be inappropriate for determining dry depo...
Modelling gaseous dry deposition in AURAMS: a unified regional air-quality modelling system
Atmospheric Environment, 2002
An upgraded parameterization scheme for gaseous dry-deposition velocities has been developed for a new regional air-quality model with a 91-species gas-phase chemistry mechanism, of which 48 species are ''transported'' species. The well-known resistance analogy to dry deposition is adopted in the present scheme, with both O 3 and SO 2 taken as base species. Stomatal resistances are calculated for all dry-depositing species using a ''sunlit/shaded big-leaf '' canopy stomatal resistance submodel. Dry-ground, wet-ground, dry-cuticle, and wet-cuticle resistances for O 3 and SO 2 , and parameters for calculating canopy stomatal resistance and aerodynamic resistance for these two base species are given as input parameters for each of the 15 land-use categories and/or five seasonal categories considered by the scheme. Dry-ground, wet-ground, dry-cuticle, and wet-cuticle resistances for the other 29 model species for which dry deposition is considered to be a significant process are scaled to the resistances of O 3 and SO 2 based on published measurements of their dry deposition and/or their aqueous solubility and oxidizing capacity. Mesophyll resistances are treated as dependent only on chemical species. Field experimental data have then been used to evaluate the scheme's performance for O 3 and SO 2. Example sets of modelled dry-deposition velocities have also been calculated for all 31 dry-deposited species and 15 land-use categories for different environmental conditions. This new scheme incorporates updated information on dry-deposition measurements and is able to predict deposition velocities for 31 gaseous species for different land-use types, seasons, and meteorological conditions.
Development and evaluation of the aerosol dynamics and gas phase chemistry model ADCHEM
Atmospheric Chemistry and Physics, 2011
The aim of this work was to develop a model suited for detailed studies of aerosol dynamics, gas and particle phase chemistry within urban plumes, from local scale (1 × 1 km 2 ) to regional scale. This article describes and evaluates the trajectory model for Aerosol Dynamics, gas and particle phase CHEMistry and radiative transfer (AD-CHEM). The model treats both vertical and horizontal dispersion perpendicular to an air mass trajectory (2-space dimensions). The Lagrangian approach enables a more detailed representation of the aerosol dynamics, gas and particle phase chemistry and a finer spatial and temporal resolution compared to that of available regional 3D-CTMs. These features make it among others well suited for urban plume studies. The aerosol dynamics model includes Brownian coagulation, dry deposition, wet deposition, in-cloud processing, condensation, evaporation, primary particle emissions and homogeneous nucleation. The organic mass partitioning was either modeled with a 2-dimensional volatility basis set (2D-VBS) or with the traditional two-product model approach. In ADCHEM these models consider the diffusion limited and particle size dependent condensation and evaporation of 110 and 40 different organic compounds respectively. The gas phase chemistry model calculates the gas phase concentrations of 61 different species, using 130 different chemical reactions. Daily isoprene and monoterpene emissions from European forests were simulated separately with the vegetation model LPJ-GUESS, and included as in-Correspondence to: P. Roldin (pontus.roldin@nuclear.lu.se) put to ADCHEM. ADCHEM was used to simulate the ageing of the urban plumes from the city of Malmö in southern Sweden (280 000 inhabitants). Several sensitivity tests were performed concerning the number of size bins, size structure method, aerosol dynamic processes, vertical and horizontal mixing, coupled or uncoupled condensation and the secondary organic aerosol formation. The simulations show that the full-stationary size structure gives accurate results with little numerical diffusion when more than 50 size bins are used between 1.5 and 2500 nm, while the movingcenter method is preferable when only a few size bins are selected. The particle number size distribution in the center of the urban plume from Malmö was mainly affected by dry deposition, coagulation and vertical dilution. The modeled PM2.5 mass was dominated by organic material, nitrate, sulfate and ammonium. If the condensation of HNO 3 and NH 3 was treated as a coupled process (pH independent) the model gave lower nitrate PM2.5 mass than if considering uncoupled condensation. Although the time of ageing from that SOA precursors are emitted until condensable products are formed is substantially different with the 2D-VBS and two product model, the models gave similar total organic mass concentrations.
Test of two numerical schemes for use in atmospheric transport-chemistry models
Atmospheric Environment. Part A. General Topics, 1993
Al~traet--Two fast integration methods for chemical kinetics are tested. One is the Quasi-steady State Approximation (QSSA) method and the other is a new Euler Backward Iterative (EBI) method. The EBI method is based on iterative solution of the Euler backward approximation of a coupled system of nonlinear ordinary differential equations of chemical kinetics. The efficiency of the iteration process is increased by using analytical solutions for groups of species which are strongly coupled. The accuracy of both integration methods is evaluated by comparing the results with solutions obtained by a Gear method, the Livermore Solver for Ordinary Differential Equations (LSODE). The chemical scheme used is the Carbon-bond Mechanism IV (CBM-IV). The numerical methods are tested on three chemical scenarios: two scenarios without emissions and with constant reaction rates and one scenario with variable emissions and photodissociation rates. Using a short time step (50 s), both EBI and QSSA perform very well, even under extreme chemical conditions. For larger time steps the EBI method performs better than QSSA. In the case of more realistic chemical conditions, both methods perform well even with a time step of 900 s. The accuracy of QSSA depends highly on the iteration procedure. Without iterations the QSSA method performs poorly.