Chemistry-transport model

Examination of equation 5 shows that if there are no chemical reactions, (R = 0), or if R is linear in and uncoupled, then a set of linear, uncoupled differential equations are formed for determining poUutant concentrations. This is the basis of transport models which may be transport only or transport with linear chemistry. Transport models are suitable for studying the effects of sources of CO and primary particulates on air quaUty, but not for studying reactive pollutants such as O, NO2, HNO, and secondary organic species. 

Refinement and Application of a Global Multicompartment Chemistry-Transport Model... 

The three dimensional multicompartmental chemistry transport model MPI-MCTM [Lammel et al (2001), Semeena and Lammel (2003), Gughelmo (2008)] was run for 40 years with a resolution of T21L19 in the atmosphere and GR30L40 in the ocean. The ocean biogeochemistry started from spin-up fields and the atmosphere from an initial run, necessitating a physical spin-up of 2 years prior to the actual simulation. Within a mn of 40 years the model produces its own climate based... 

Semeena VS, Lammel G (2003) Effects of various scenarios of entry of DDT and y-HCH on the global environmental fate as predicted by a multicompartment chemistry-transport model. Fresenius Environmental Bulletin 12 925-939... 

Laboratory measurements (17) next showed that reaction R19 proceeded about 40 times faster than determined earlier, strongly promoting ozone production and increasing HO concentrations with major consequences for tropospheric and stratospheric chemistry. Table I presents an ozone budget calculated with a three-dimensional chemistry transport model of the troposphere which takes into account the afore mentioned reactions. 

Model calculations performed during PAUR I included three-dimensional regional Chemistry-Transport Models to study chemical processes and transport at the regional and the urban level and radiation transfer models. These models were applied for a number of ozone depletion scenaria. 

Wauben W.M.F., P.F.J. van Velthoven and H. Kelder, 1997a A 3-D chemistry transport model study of changes in atmospheric ozone due to aircraft NO emissions, Atmos. Env.,31, 1819-1836. 

Schaap et al. [145] proposed a simple methodology to account for traffic re-suspension emissions in a large-scale modelling application by means of the 3D chemistry-transport model LOTOS-EUROS [150] ... 

During the last two decades or so several chemistry-transport models have been developed in Europe and elsewhere. They are already widely applied for PM exposure and health-related issues, at local, urban and regional scales, but an effort is still needed to take more advantage of this third generation models (Chemical Transport Models including aerosol chemistry) on epidemiological studies. 

Vautard R, Builtjes PHJ, Thunis P, Cuvelier C, Bedogni M, Bessagnet B, Honore C, Moussiopoulos N, Pirovano G, Schaap M, Stem R, Tarrason L, Wind P (2007) Evaluation and intercomparison of Ozone and PM10 simulations by several chemistry transport models over four European cities within the CityDelta project. Atmos Environ 41 173-188... 

Such a complicated interactivity of processes can both directly and indirectly affect formation of the atmospheric greenhouse effect. Derwent et al. (2001) described a global 3-D Lagrangian chemistry transport model (STOCHEM) which reproduces chemical processes including MGC transport and can be used to reproduce interrelated fields of TO and methane concentration (Johnson et al., 2002) under conditions of emission to the atmosphere of short-lived TO precursors such as CH4, CO, NOx, and hydrogen. At the same time, the radiative forcing (RF) of NOx emissions depends on the location of emissions near the surface or in the upper troposphere, in the Northern or Southern Hemisphere. For each short-lived MGC/... 

Stratosphere Troposphere Interactions and the Biosphere A global 3-D Lagrangian chemistry transport model Scientific and Technical Translation... 

Wolke R, Hellmuth O, Knoth O, Schroder W, Heinrich B, Renner E (2003) The chemistry-transport modelling system LM-MUSCAT description and CITYDELTA applications. Proceedings of the 26th international technical meeting on air pollution and its application. Istanbul, May 2003, pp 369-379... 

Coupling Global Atmospheric Chemistry Transport Models to ECMWF Integrated Forecasts System for Forecast and Data Assimilation Within GEMS... 

The most common type of coupling is 2D in space, i.e. the coupled models cover separate 3D domains, such as atmosphere and ocean, which are connected to each other by a 2D interface. Less common is 3D coupling in which both models cover the same or an overlapping spatial domain, e.g. the atmosphere, but consider different aspects of it as in the case of weather forecasts models and chemistry transport models. The amount of data to be exchanged is bigger in 3D coupling and there are further consistency issues if both models simulate the same processes such as transport but in a different way (see Section 10.2.4). 

Coupling Global Atmospheric Chemistry Transport Models... 

Coupling Global Atmospheric Chemistry Transport Models Couple IFS / CTM run memory in kB... 

The Atmospheric Chemistry Transport modelling system used is based on the off-line coupled CAMx and HIRLAM models has been developed to simulate particulate and gas-phase air pollution on different scales. It has been used to simulate short and longterm releases of different chemical species and air pollution episodes. At present it is run in a pre-operational mode 4 times per day based on 3D meteorological fields produced by the HIRLAM NWP model. Currently this modelling system is setup to perform chemical weather forecasts for a series of chemical species (such as O3, NO, NO2, CO and SO2) and forecasted 2D fields at surface are available for each model as well as an ensemble of models (based on 12 European regional air quality models). The simulated output is publicly available and it is placed at the ECMWF website (http //gems.ecmwf.int/d/products/raq/forecasts/) of the EC FP6 GEMS project. 

The global chemistry transport model (CTM) part is based on the CHASER model, which is based on CCSR/NIES/FRCGC atmospheric general circulation model (AGCM) version 5.7b. The basic features of the model have been already described in Sect. 2. The regional CTM part is based on WRF/Chem (Grell et al. 2005). The databases used are the following ... 

The multiscale meteorology and chemistry model system M-SYS consists of the mesoscale models MEsoscale TRAnsport and Stream (METRAS Schliinzen 1990 Schliinzen and Katzfey 2003) and MEsoscale Chemistry Transport Model (MECTM Muller et al. 2000 Schliinzen and Meyer 2007), which are used in... 

Lenz C-J, Muller F, Schliinzen KH (2000) The sensitivity of mesoscale chemistry transport model results to boundary values. Environ Monit Assess 65 287-298 L6pez SD, Liipkes C, Schliinzen KH (2005) The effects of different k-e-closures on the results of a micro-scale model for the flow in the obstacle layer. Meteorol Z 14 839-848 Muller F, Schliinzen KH, Schatzmann M (2000) Test of numerical solvers for chemical reaction mechanisms in 3D air quality models. Environ Model Softw 15 639-646 Schliinzen KH (1990) Numerical studies on the inland penetration of sea breeze fronts at a coastline with tidally flooded mudflats. Beitr Phys Atmos 63 243-256 Schliinzen KH, Katzfey JJ (2003) Relevance of subgrid-scale land-use effects for mesoscale models. Tellus 55A 232-246... 

There is a clear difference in needs for the on-line coupling of chemistry transport models and the off-line coupling. For the off-line coupled models it would advantageous to improve the quality of meteorological outputs, especially for fair weather conditions (including calm conditions and a focus on extreme situations). Parameters that can be used directly in off-line coupled models and that are important for processes like rainout should also be readily available. (It is important to remember that the couplings can be done in two directions not only from NWP to atmospheric CTM, but also from atmospheric CTM to NWP, see above). 

Tijm S, Baklanov A, Rontu L (2007) HIRLAM air chemistry transport modelling and numerical weather prediction. Conclusions from HIRLAM/HARMONIE-ACT models integration session, COST728-NetFAM workshop, 28.5.2007. http //netfam.fmi.fi/Integ07/HARMONIE followup.doc... 

Leip, A. and Lammel, G. (2004) Indicators for persistence and long-range transport potential as derived from multicompartment chemistry-transport modelling. Environmental Pollution, 128, 205-221. 

Brasseur, G.P., and S. Madronich, Chemistry-transport models, in Climate System Modeling. K.E. Trenberth, ed., Cambridge University Press, 1992. 

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