Catálogo de publicaciones - libros

During a nuclear accident in which radionuclides are released to the atmosphere automatic off-site gamma radiation measurements may be used to assess the source strength and the dispersion of radionuclides. In the following, a newly developed sequential data assimilation method for such on-line source term estimation is presented and results are shown using both real and simulated radiation data.1 The method is based on a discrete-time, stochastic state space model describing the dynamics of the significant plume parameters (the state variables) and their coupling to measurements through a non-linear atmospheric dispersion model.

The advances examined by the Air Qulity Modelling Systems have been quite important in the last five years. The tirad generation of Air Quality Modelling Systems such as MM5 (PSU/NCAR) and CMAQ (EPA, USA) is a reliable software tool to simulate the air quality concentrations. Advances in computer capabilities in recent years have been also considerable and the capability to use a set of PC’s (clusters) to run complex models such as MM5 and CMAQ is nowadays a real issue. The Eulerian non-hydrostatic mesoscale meteorological models and dispersión models including chemistry with clouds and aerosols are today reliable software tools which can be used in real-time and forecasting mode

Currently within the licensing procedure of nuclear facilities in Germany, atmospheric dispersion calculations are still predominantly based on the simple Gaussian plume approach. Advanced model systems consisting of a diagnostic flow model together with a Lagrangian particle simulation model, as e.g. described in a guideline of the German Association of Engineers (VDI 3945 part 3)1, have less restrictions with respect to terrain effects, source configuration and nonstationary conditions.

Residential buildings in cities are ventilated using different systems for ventilation. Except for systems that consist in opening windows, there are more sophisticated systems that are controlled by different manners. Among them, hybrid systems are recently gaining more attention as they promise to be energy effective with a good control of indoor air quality. Operation of such ventilation systems can be significantly influenced by airflow in street canyons. Thus, correct prediction of airflow is a prerequisite for efficient functioning of such systems. Authors of this paper choose Agiou Fanouriou street canyon in Athens as a test canyon for comparison of modeling and field measurements.

The objective of this study is to analyse the meteorological fields and the dispersion patterns of different pollutants released by several types of industries on a heavily industrialized region located in the NE part of Spain. Petrochemical industries and several chemical plants are concentrated in an industrial park placed near the shoreline of the Mediterranean Sea and close to a relatively high mountain range, facts which increase the complexity of the wind fields in the region and therefore of the resultant pollutant dispersion patterns. Numerical modelling has been carried out with two different models: the 3-D Urban Airshed Model with variable grid (UAM-V) (Biswas et al., 2001), implemented to MM5 meteorological model (Grell et al. 1994); and an Australian model TAPM ( Luhar and Hurley, 2003), which has its own photochemical module. The models have been run from the 7th to 9th of August 2003, during a summer ozone episode mainly characterized by a synoptic situation of high pressures which favour the development of mesoscale circulations forced by the topography. First results show how meteorological fields are certainly a critical component of the dispersion modeling systems because in this area local wind circulations are the main cause of the plume dispersion. In consequence, its evaluation is considered as a preliminary and an important point of this study. Afterwards a comparison between the dispersion patterns given by the two different photochemical is carried out and agreements and differences are analyzed.

Odor episodes are of particular concern in Catalonia, a region in NE Spain with an important industrial sector whose facilities, on many occasions, are located very close to population areas. In this contribution we show a methodology that has been applied to investigate the origin of bad odors episodes. The procedure combines, on one hand, an analytical approach, based on the acquisition of samples, and which requires the participation of the affected population; and on the other hand, a modeling approach, based on the use of mesoscale meteorological models to track back in time the origin of the air mass responsible of the discomfort. The system has been applied to the investigation of odor episodes suspected to be caused by a landfill facility.

Backward trajectories from Buenos Aires, Argentina, were used in an exploratory study to characterize the airflow and the relationship with synoptic patterns and to contribute to the identification of air pollution source regions. Buenos Aires is the most populated city of the country. Air pollution climatology studies have shown that there is an important frequency of reduced ventilation conditions, especially during the cold season (Ulke, 2000). Case studies have demonstrated the transport of biomass burning products from Brazil during the tropical dry season toward the region (Longo et al, 1999).

Receptor-oriented methodologies have been recently used to provide maps of potential sources for particular target species. Here, a receptor-oriented methodology has been applied to the chemistry of precipitation data collected at a background site in NE Spain (La Castanya rural station, LC) in order to identify the likely sources of anthropogenic pollutants (SO4 2-, NO3-, NH4+) and alkaline species to this site. The concentration fields were obtained on the basis of the residence time of the air mass trajectories in each source region.

The lateral dispersion parameter is a statistical quantity of great interest both for dispersion modelling and for the derivation of fundamental relations associated to the turbulence study. The purpose of the present investigation is to derive a new expression for the turbulence dissipation rate. The development consists on a binomial expansion of an algebraic relation for the lateral dispersion parameter originated from the fitting of esperimental data.

The literature regarding the Convective Boundary Layer (CBL) at early morning transition is scarce. Most papers are focused on the growth after convection is fully established. Tennekes (1973) proposes a conceptual model for the time required to erode the nocturnal inversion, while Kaimal et al. (1976) show a ‘typical’ diurnal cycle of surface heat flux and Convective Boundary Layer depth, but this begins after the surface heat flux is already positive. Wyngaard (1983) discusses the morning (‘neutral-convective’) transition briefly, and makes the point that only a relatively small buoyancy flux is needed to cause the transition. In this work, starting from the spectral form of the turbulent energy equation, a model for the CBL growing is described.