Highly Resolving Models

The quality of numerical simulations is limited by the horizontal and vertical model resolution. An obvious aspect of enhanced model resolution is the better representation of the bathymetry. Especially the structured coastline of the Danish Straits and the sills between the basins of the Baltic Sea are represented more accurately. Another aspect is the representation of processes with small characteristic dynamic scales in the model. Although in many cases details on unresolved processes are not needed, parameterizations for such processes are sources of numerical uncertainty. Enhanced model resolution means less parameterization and the model dynamics is represented preferably by the hydrodynamic equations. 

Horizontal and vertical advection of heat and dissolved substances implies numerical mixing, which is the less important the smaller the grid cell volume is. Hence, abetter model resolution conserves the signamre of inflowing saltwater, which is essential for the simulation of bottom water renewal in the deep basins of the Baltic Sea. Also for the representation of frontal or river plume dynamics, a sufficient model resolution is required. 

Generally, the appropriate representation of baroclinic flows in the model requires the resolution of the baroclinic Rossby radius as the typical horizontal length scale. If this resolution is not achieved, baroclinic processes are governed by friction and advection, while the important contribution of barotropic waves is hidden in parameterizations. 

To illustrate the effects of the enhancement of the model resolution, we show an example 

FIGURE 19.17 Snapshot of the vertically averaged velocity from similar models with different 

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The cylinder stretching protocol appears to work very well for simple solvent-free membrane models [111, 113, 114], but with more refined models this method suffers from two drawbacks, both related to the equifibration of a chemical potential. First, the cylinder separates the simulation volume into an inside and an outside. If solvent is present, its chemical potential must be the same in these two regions, but for more highly resolved models the solvent permeability through the bilayer is usually too low to ensure automatic relaxation. Second, the chemical potential of lipids also has to be the same in the two bilayer leaflets, and again for more refined models the lipid flip-flop rate tends to be too low for this to happen spontaneously. 

Furthermore, there can be identified two opposing trends in model development. One is a trend toward more detailed models with higher fidelity to the real system, driven by the availability of highly resolved environmental data, increases in computer power, and progress in atmospheric and earth sciences. The other trend is toward models that are tailor-made to specific scientific questions or decision-making problems, driven by the philosophy of parsimony and the increase in the need for scientific results as a basis for decision-making in modem society. 

Many protein kinases show indistinct substrate specificity, especially in in vitro experiments. Certain phosphorylation sites of the histone HI can be phosphorylated by various protein kinases. Insight into the specificity requirements of protein kinases was only possible once highly resolved structural information on the binding of model substrates to protein kinases was available (see 7.1.4). 

Spectroscopic methods can yield the required understanding of the complexes. Especially optical spectroscopy provides very detailed information about electronic and vibronic structures, in particular, when highly resolved spectra are available. However, without the development of suitable models, which are usually based on perturbation theory, group theory, and recently also on ab-initio calculations, a thorough understanding of the complexes is very difficult to achieve. In this volume and in a subsequent one some leading researchers will show that such a detailed description of... 

Photodissociation of small polyatomic molecules is an ideal field for investigating molecular dynamics at a high level of precision. The last decade has seen an explosion of many new experimental methods which permit the study of bond fission on the basis of single quantum states. Experiments with three lasers — one to prepare the parent molecule in a particular vibrational-rotational state in the electronic ground state, one to excite the molecule into the continuum, and finally a third laser to probe the products — are quite usual today. State-specific chemistry finally has become reality. The understanding of such highly resolved measurements demands theoretical descriptions which go far beyond simple models. 

The astrophysical models of protoplanetary disks based on optical observations and laboratory experiments and meteoritic measurements provide the basis for theories of nebular evolution. The best and most precise relevant measurements are from meteoritic analysis. Meteorites from the Asteroid Belt of our Solar System are the best record of the evolution of the solar nebula from a gas-dust mixture to an organized planetary system. The addition of cometary and solar-wind sample analysis complement these data. Combination of fundamental laboratory-based experiments and modeling efforts has led to a highly resolved understanding of the chemical conditions and processes in the primordial solar nebula (see Chapter 6). In this chapter an overview of recent advances in our understanding of the chemical and isotopic evolution of the early Solar System and protoplanetary disks is presented. 

The model system generally uses EMEP emissions. For the countries - Austria, Czech Republic, Slovakia and Hungary - the original 50 x 50 km data are down-scaled to 5 X 5 km based on an inventory from 1995 (Winiwarter and Zueger 1996). The EMEP data for 1999 (used for 2005 forecast) have been substituted by data for 2003 (Vestreng et al. 2004). In addition, a new highly resolved emission inventory for the city of Vienna, Austria (Orthofer et al. 2005) is used for this area. 

The recent electron spectrometer provides highly resolved spectrum for valence state XPS, which supplies us with very useful information for discussion on chemical bonding, when combined with an appropriate theoretical analysis as mentioned above. Therefore, an accurate calculation of electronic state is required for such a purpose. The DOS calculated by DV-Xa method has been demonstrated to reproduce well the valence state XPS for some oxyanions compared with other theoretical calculations. The calculation was made using a simple model cluster XO4 " with T symmetry, thus the theoretical analysis was insufficient for the valence structure in details. This has significantly been improved by a careful analysis with more realistic model clusters which are determined from crystallographic data for those oxyanions. The comparison of the theoretical and experimental spectra for PO4 ions is shown in Fig.8. The agreement is very good even for the fine structure in the valence band. 

In an ATR imaging study, Kazarian and Chan described the behavior of polymer blends under high-pressure COj. Under these conditions and at 40 °C, initially homogeneous blends were seen to undergo a phase separation. By using this method, it was also possible to examine the influence of other gases on the material properties of polymers [17]. Likewise, in 2006, Kaun et al. demonstrated an FT-IR imaging system for the examination of a chemical reaction in a solution, and the time-resolved model reaction of formaldehyde and sulfite was also visualized [18]. 

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