A chemical transport model (CTM) is a type of computer numerical model which typically simulates atmospheric chemistry and may give air pollution forecasting.
While related general circulation models (GCMs) focus on simulating overall atmospheric dynamics (e.g. fluid and heat flows), a CTM instead focuses on the stocks and flows of one or more chemical species. Similarly, a CTM must solve only the continuity equation for its species of interest, a GCM must solve all the primitive equations for the atmosphere; but a CTM will be expected to accurately represent the entire cycle for the species of interest, including fluxes (e.g. advection), chemical production/loss, and deposition. That being said, the tendency, especially as the cost of computing declines over time, is for GCMs to incorporate CTMs for species of special interest to climate dynamics, especially shorter-lived species such as nitrogen oxides and volatile organic compounds; this allows feedbacks from the CTM to the GCM's radiation calculations, and also allows the meteorological fields forcing the CTM to be updated at higher time resolution than may be practical in studies with offline CTMs.
CTMs may be classified according to their methodology and their species of interest, as well as more generic characteristics (e.g. dimensionality, degree of resolution).
Jacob (1999) [1] classifies CTMs as Eulerian/"box" or Lagrangian/"puff" models, depending on whether the CTM in question focuses on [1]
An Eulerian CTM solves its continuity equations using a global/fixed frame of reference, while a Lagrangian CTM uses a local/moving frame of reference.
Numerical climate models use quantitative methods to simulate the interactions of the important drivers of climate, including atmosphere, oceans, land surface and ice. They are used for a variety of purposes from study of the dynamics of the climate system to projections of future climate. Climate models may also be qualitative models and also narratives, largely descriptive, of possible futures.
A general circulation model (GCM) is a type of climate model. It employs a mathematical model of the general circulation of a planetary atmosphere or ocean. It uses the Navier–Stokes equations on a rotating sphere with thermodynamic terms for various energy sources. These equations are the basis for computer programs used to simulate the Earth's atmosphere or oceans. Atmospheric and oceanic GCMs are key components along with sea ice and land-surface components.
The Carl-Gustaf Rossby Research Medal is the highest award for atmospheric science of the American Meteorological Society. It is presented to individual scientists, who receive a medal. Named in honor of meteorology and oceanography pioneer Carl-Gustaf Rossby, who was also its second (1953) recipient.
Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied. It is a multidisciplinary approach of research and draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and volcanology and other disciplines. Research is increasingly connected with other areas of study such as climatology.
The Max Planck Institute for Chemistry is a non-university research institute under the auspices of the Max Planck Society in Mainz, Germany. It was created as the Kaiser Wilhelm Institute for Chemistry in 1911 in Berlin.
CLaMS is a modular chemistry transport model (CTM) system developed at Forschungszentrum Jülich, Germany. CLaMS was first described by McKenna et al. (2000a,b) and was expanded into three dimensions by Konopka et al. (2004). CLaMS has been employed in recent European field campaigns THESEO, EUPLEX, TROCCINOX SCOUT-O3, and RECONCILE with a focus on simulating ozone depletion and water vapour transport.
The National Atmospheric Release Advisory Center (NARAC) is located at the University of California's Lawrence Livermore National Laboratory. It is a national support and resource center for planning, real-time assessment, emergency response, and detailed studies of incidents involving a wide variety of hazards, including nuclear, radiological, chemical, biological, and natural emissions.
NAME atmospheric pollution dispersion model was first developed by the UK's Met Office in 1986 after the nuclear accident at Chernobyl, which demonstrated the need for a method that could predict the spread and deposition of radioactive gases or material released into the atmosphere.
The following outline is provided as an overview of and topical guide to air pollution dispersion: In environmental science, air pollution dispersion is the distribution of air pollution into the atmosphere. Air pollution is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing disease, death to humans, damage to other living organisms such as food crops, and the natural or built environment. Air pollution may come from anthropogenic or natural sources. Dispersion refers to what happens to the pollution during and after its introduction; understanding this may help in identifying and controlling it.
Over the last two centuries many environmental chemical observations have been made from a variety of ground-based, airborne, and orbital platforms and deposited in databases. Many of these databases are publicly available. All of the instruments mentioned in this article give online public access to their data. These observations are critical in developing our understanding of the Earth's atmosphere and issues such as climate change, ozone depletion and air quality. Some of the external links provide repositories of many of these datasets in one place. For example, the Cambridge Atmospheric Chemical Database, is a large database in a uniform ASCII format. Each observation is augmented with the meteorological conditions such as the temperature, potential temperature, geopotential height, and equivalent PV latitude.
The Kinetic PreProcessor (KPP) is an open-source software tool used in atmospheric chemistry. Taking a set of chemical reactions and their rate coefficients as input, KPP generates Fortran 90, FORTRAN 77, C, or Matlab code of the resulting ordinary differential equations (ODEs). Solving the ODEs allows the temporal integration of the kinetic system. Efficiency is obtained by exploiting the sparsity structures of the Jacobian and of the Hessian. A comprehensive suite of stiff numerical integrators is also provided. Moreover, KPP can be used to generate the tangent linear model, as well as the continuous and discrete adjoint models of the chemical system.
Austal2000 is an atmospheric dispersion model for simulating the dispersion of air pollutants in the ambient atmosphere. It was developed by Ingenieurbüro Janicke in Dunum, Germany under contract to the Federal Ministry for Environment, Nature Conservation and Nuclear Safety.
ECHAM is a general circulation model (GCM) developed by the Max Planck Institute for Meteorology, one of the research organisations of the Max Planck Society. It was created by modifying global forecast models developed by ECMWF to be used for climate research. The model was given its name as a combination of its origin and the place of development of its parameterisation package, Hamburg. The default configuration of the model resolves the atmosphere up to 10 hPa, but it can be reconfigured to 0.01 hPa for use in studying the stratosphere and lower mesosphere.
Turbulent diffusion is the transport of mass, heat, or momentum within a system due to random and chaotic time dependent motions. It occurs when turbulent fluid systems reach critical conditions in response to shear flow, which results from a combination of steep concentration gradients, density gradients, and high velocities. It occurs much more rapidly than molecular diffusion and is therefore extremely important for problems concerning mixing and transport in systems dealing with combustion, contaminants, dissolved oxygen, and solutions in industry. In these fields, turbulent diffusion acts as an excellent process for quickly reducing the concentrations of a species in a fluid or environment, in cases where this is needed for rapid mixing during processing, or rapid pollutant or contaminant reduction for safety.
TOMCAT/SLIMCAT is an off-line chemical transport model (CTM), which models the time-dependent distribution of chemical species in the troposphere and stratosphere. It can be used to study topics such as ozone depletion and tropospheric pollution, and was one of the models used the IPCC report on Aviation and the Global Atmosphere. It incorporates a choice of detailed chemistry schemes for the troposphere or stratosphere, and an optional chemical data assimilation scheme.
The history of numerical weather prediction considers how current weather conditions as input into mathematical models of the atmosphere and oceans to predict the weather and future sea state has changed over the years. Though first attempted manually in the 1920s, it was not until the advent of the computer and computer simulation that computation time was reduced to less than the forecast period itself. ENIAC was used to create the first forecasts via computer in 1950, and over the years more powerful computers have been used to increase the size of initial datasets and use more complicated versions of the equations of motion. The development of global forecasting models led to the first climate models. The development of limited area (regional) models facilitated advances in forecasting the tracks of tropical cyclone as well as air quality in the 1970s and 1980s.
The Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT) is a computer model that is used to compute air parcel trajectories to determine how far and in what direction a parcel of air, and subsequently air pollutants, will travel. HYSPLIT is also capable of calculating air pollutant dispersion, chemical transformation, and deposition. The HYSPLIT model was developed by the National Oceanic and Atmospheric Administration (NOAA) Air Resources Laboratory and the Australian Bureau of Meteorology Research Centere in 1998. The model derives its name from the usage of both Lagrangian and Eulerian approaches.
CMAQ is an acronym for the community multiscale air quality model, a sophisticated three-dimensional Eulerian grid chemical transport model developed by the US EPA for studying air pollution from local to hemispheric scales. EPA and state environmental agencies use CMAQ to develop and assess implementation actions needed to attain National Ambient Air Quality Standards (NAAQS) defined under the Clean Air Act. The CMAQ simulates air pollutants of concern—including ozone, particulate matter (PM), and a variety of air toxics — to optimize air quality management. Deposition values from the CMAQ are used to assess ecosystem impacts such as eutrophication and acidification from air pollutants. In addition, the National Weather Service uses the CMAQ to produce twice-daily forecast guidance for ozone air quality across the U.S. The CMAQ unites the modeling of meteorology, emissions, and chemistry to simulate the fate of air pollutants under varying atmospheric conditions. Other kinds of models—including crop management and hydrology models— can be linked with the CMAQ simulations, as needed, to simulate pollution more holistically across environmental media.
CHIMERE is a chemistry-transport model. It is a computer code that unites a set of equations representing the transport and the chemistry of atmospheric species making it possible to quantify the evolution of air masses and pollution plumes as a function of time on different scales. Using meteorological inputs and emission fluxes, CHIMERE calculates three-dimensional concentrations of pollutants in the atmosphere. Due to the input data used, the number of equations that are solved and the physico-chemistry included in the model, CHIMERE is considered to be a mesoscale model, i.e. simulating the troposphere for a horizontal resolution of 1 to 100 km and over study areas ranging from the city to the hemisphere.