Spatial distribution, atmospheric

Assessing the spatial distribution of NHj emissions is of particular interest because of the link with ecological impacts of nitrogen deposition. Using statistical atmospheric transport models, such emission maps may be used to... 

Wilson, D. J., A. G. Robins, and J. E. Fackrell. 1982b. Predicting the spatial distribution of concentration fluctuations from a ground level source. Atmospheric Environ. 16(3) 479-504. 

Budgets and cycles can be considered on very different spatial scales. In this book we concentrate on global, hemispheric and regional scales. The choice of a suitable scale (i.e. the size of the reservoirs), is determined by the goals of the analysis as well as by the homogeneity of the spatial distribution. For example, in carbon cycle models it is reasonable to consider the atmosphere as one reservoir (the concentration of CO2 in the atmosphere is fairly uniform). On the other hand, oceanic carbon content and carbon exchange processes exhibit large spatial variations and it is reasonable to separate the... 

In the individual compartments quasi-steady state is achieved depending on emissions, degradation rates and spatial distribution of DDT. According to the seasonality of the parameters affecting degradation rates, e.g. temperature and oxidant abundance, the compartmental burdens in steady state follow a seasonal cycle. As the sources and consequently most of the DDT mass is located in the northern hemisphere, the cycle is defined by the climate of that hemisphere. Times needed to to achieve quasi staty state in the compartments are equal in the AGG and SAT experiment, as well as amplitude and phase of the burden time series. Vegetation reaches quasi-steady state within 2-4 years, and atmosphere already within 2 years. These... 

DDE The comparison of model data with observations shows significant discrepancies for the spatial distribution in atmosphere and ocean. The observed concentrations show a decrease from low to high latitudes, whereas the model results show an increase of oceanic concentrations. Therefore, modeled concentrations in the Arctic atmosphere strongly exceed observations. In general, possible could be in-... 

A significant amount of lead emitted in a country is transported beyond the national borders contributing to the trans-boundary transport. In 2002 as much as 4.8 kt (around 60% of total anthropogenic emission) of atmospheric lead, emitted in Europe were involved in transport across state borders. Absolute magnitudes of lead transported outside countries vary substantially from country to country. It was calculated as difference between national emission and deposition to the country. This magnitude depends on national emission, size of the territory, climatic conditions and spatial distribution of emission sources within the country. 

One of model s main results is spatial distribution of POP depositions and air concentrations. Calculated fields of depositions and concentrations give the opportunity to assess the changes in atmospheric contamination and deposition of POPs and to select hot spots of contamination. As an example, the spatial distribution ofPCDD/Fs depositions to the EMEP region, calculated for the beginning and the end of the considered period, is given in Figure 4. Hot spots are particular cells of the EMEP... 

Equation (2.2) can be considered as the fundamental governing equation for the concentration of an inert constituent in a turbulent flow. Because the flow in the atmosphere is turbulent, the velocity vector u is a random function of location and time. Consequently, the concentration c is also a random fimction of location and time. Thus, the dispersion of a pollutant (or tracer) in the atmosphere essentiaUy involves the propagation of the species molecules through a random medium. Even if the strength and spatial distribution of the source 5 are assumed to be known precisely, the concentration of tracer resulting from that source is a random quantity. The instantaneous, random concentration, c(x, y, z, t), of an inert tracer in a turbulent fluid with random velocity field u( c, y, z, t) resulting from a source distribution S x, y, z, t) is described by Eq. (2.2). 

Tremolada, P., V. Burnett, D. Calamari, and K. C. Jones, Spatial distribution of PAHs in the UK atmosphere using pine needles , Environ. Sci. Technol., 30, 3570-3577 (1996). 

As previously mentioned, molecules that are present within the interface may be able to bind or release electrons from the outer electron hull that surrounds the positively charged proton-neutron core—i.e., they can be ionized. In systems with interfacial boundaries containing ions that carry a charge, a spatial distribution of counter ions surrounding the interface will develop. The number of counter ions will decrease as the distance from the interface increases. The counter ion atmosphere is also referred to as the ion cloud. The... 

Many studies have shown that in North Europe major biomass burning emissions are mostly linked with wood smoke from fireplaces and stoves, whereas in Southern Europe wildfires can be the most important biomass combustion source. The Mediterranean region is frequently under the influence of this phenomenon, especially during dry periods. Although wildfires can be a major contributor of particulate matter into the atmosphere, forest fire emissions are poorly quantified in the literature, due to the difficulties induced in estimating their temporal and spatial distribution. 

In recent years it has been recognized that dynamic factors contribute much to observed temperature trends. For instance, in 1995 a marked similarity was observed between the spatial distributions of the SAT field and NAM fluctuations for the last 30 years, with a clear increase in the NAM index. The increasing trend of the index was accompanied by mild winters, changes in the spatial distribution of precipitation in Europe, and ozone layer depletion in the latitudinal belt >40°N. Similar data are available for the Southern Hemisphere. The main conclusion is that along with the ENSO event, both NAM and SAM are the leading factors in global atmospheric variability. In this connection, attention should be focused on the problem of the 30-year trend of NAM toward its increase, the more so that after 1995 the index lowered. It is still not clear whether this trend is a part of long-term oscillations. 

All models of the C02 cycle need improvement in the way they detail the spatial distribution of soil-plant formations and in the way they specify exchange processes in the ocean and at the atmosphere-ocean boundary. Accurate parameterizations of all studied elements of the biogeochemical carbon cycle should be synthesized into a single system. Such an attempt was made in the block scheme of the model shown in Figure 3.6. The main sources of C02 are the day-to-day activity of land and marine animals, photochemical reactions, decomposition of dead organic... 

Table 3.15. The spatial distribution of A//32 = //f — //, (GtC/km2/solar year) estimated from averaged values of the assimilation and emission of CO2 at the atmosphere-ocean border since the beginning of industrialization (

There are various approaches to parameterizing the process of formation and destruction of the ozone layer. The difficulty of deriving dynamic models of the ozone cycle in the atmosphere has to do with the participation in the cycle of more than 75 chemical reactions, a qualitative and quantitative description of which is impossible without deriving detailed models of the many minor gas components of the atmosphere. Nevertheless, there are empirical models of the ozone layer, which make it possible, under the present climatic situation, to obtain adequate spatial distributions of ozone. For instance, Bekoryukov and Fedorov (1987) derived a simple empirical model of total ozone content confirmed by observational data for the Southern Hemisphere ... 

The atmospheric transport of heavy metals, oil hydrocarbons, and radionuclides is described by many models (Phillips et al., 1997 Payne et al., 1991 Sportisse, 2000). Application of these models to the reconstruction of the pollution distribution over Q makes it possible to estimate optimal values of Atp, AA and time steps At. The present level of the database for the Arctic Basin provides for use of a single-level Euler model with At = 10 days, A

pollution sources can be located at the Arctic Basin boundary. Detailed distributions of these pollution sources are given as SSMAE input. The transport of pollutants to the Arctic Basin and the formation of their spatial distribution are realized in conformity with the wind velocity field, which is considered as given (Krapivin and Phillips, 2001a, b). 

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