05/18/1993 - Eastern\u27s 1993 All Student Show Winner Laura Brahos.pdf

This paper reports on the stages forming a model evaluation protocol for urban flow and dispersion models proposed within the COST Action 732 on "Quality Assurance and Improvement of Micro-Scale Meteorological Models". It discusses the different components forming model evaluation with emphasis on validation and implementation of the protocol for the test case Mock Urban Setting Test (MUST). The protocol was proposed with building-resolving models in mind, but integral models have also been included. The suggested approach can be used for further micro-scale model evaluation and for the standardisation of their applications

Comparisons of model simulations with observations of mean flow and turbulence within simple obstacle arrays

A three-dimensional numerical code with unstructured tetrahedral grids, the finite element flow solver (FEFLO), was used to simulate the mean flow and the turbulence within obstacle array configurations consisting of simple cubical elements. Model simulations were compared with observations from a hydraulic water flume at the University of Waterloo. FEFLO was run in large eddy simulation mode, using the Smagorinsky closure model, to resolve the larger scales of the flow field. There were four experiment test cases consisting of square and staggered arrays of cubical obstacles with separations of 1.5 and 0.5 obstacle heights. The mean velocity profile for the incoming neutral boundary layer was approximated by a power law, and the turbulent fluctuations in the approach flow were generated using a Monte Carlo model. The numerical simulations were able to capture, within 40% on average, the general characteristics of the mean flow and the turbulence, such as the strong mean wind shears and the maximum turbulence at the elevation of the obstacles and the nearly constant mean wind and the 50% reduction in the turbulent velocity within the obstacle canopy. As expected, the mean wind speeds were significantly decreased (by about a factor of two or three) in the array with closer obstacle packing. It was found that, a “street canyon” effect was more obvious for the square arrays, with higher flow speeds in between the obstacles, than for the staggered arrays

THE MUST MODEL EVALUATION EXERCISE: PATTERNS IN MODEL PERFORMANCE

As part of the COST 732 action more than a dozen different research groups have modelled the MUST experiment, as simulated in a wind tunnel. The model evaluation guidance developed within COST 732 recommends \u27exploratory data analysis\u27 as one of the elements in model validation. Experience has shown that such exploratory analysis is crucial to reveal shortcomings of models that might otherwise pass unnoticed. Conditions are best for detecting common patterns and anomalies if you have a situation where several models are put into a common framework – like the case at hand. The available material provides a unique opportunity to identify and explore patterns within model performance

THE MUST MODEL EVALUATION EXERCISE: STATISTICAL ANALYSIS OF MODELLING RESULTS

The first validation exercise of the COST action 732 lead to a substantial number of simulation results for comparison with the MUST wind tunnel experiments. Validation metrics for selected simulation results of the flow field and the concentrations are presented and compared to the state of the art. In addition mean metrics and corresponding scatter limits are computed from the individual results

Identification and Characterization of Two Novel RNA Viruses from Anopheles gambiae Species Complex Mosquitoes

Mosquitoes of the Anopheles gambiae complex display strong preference for human blood-meals and are major malaria vectors in Africa. However, their interaction with viruses or role in arbovirus transmission during epidemics has been little examined, with the exception of O'nyong-nyong virus, closely related to Chikungunya virus. Deep-sequencing has revealed different RNA viruses in natural insect viromes, but none have been previously described in the Anopheles gambiae species complex. Here, we describe two novel insect RNA viruses, a Dicistrovirus and a Cypovirus, found in laboratory colonies of An. gambiae taxa using small-RNA deep sequencing. Sequence analysis was done with Metavisitor, an open-source bioinformatic pipeline for virus discovery and de novo genome assembly. Wild-collected Anopheles from Senegal and Cambodia were positive for the Dicistrovirus and Cypovirus, displaying high sequence identity to the laboratory-derived virus. Thus, the Dicistrovirus (Anopheles C virus, AnCV) and Cypovirus (Anopheles Cypovirus, AnCPV) are components of the natural virome of at least some anopheline species. Their possible influence on mosquito immunity or transmission of other pathogens is unknown. These natural viruses could be developed as models for the study of Anopheles-RNA virus interactions in low security laboratory settings, in an analogous manner to the use of rodent malaria parasites for studies of mosquito anti-parasite immunity

Intercomparison of two modeling approaches for traffic air pollution in street canyons

International audienceWe present an intercomparison of two models applied to a major boulevard in a Paris suburb accounting for building effects: (1) a computational fluid dynamics (CFD) model providing a detailed three-dimensional representation of the atmospheric flow and pollutant dispersion (Code_Saturne) and (2) a street-network model with well-mixed steady-state concentrations within street segments coupled with a regional chemical-transport model (SinG). Simulations were performed for five cases representing different meteorological conditions (wind direction and speed) and two sensitivity cases with different emissions. We compare model results to measurements of NOx at two monitoring stations on either side of the street. Results exhibit (a) a complex behavior highlighting effects of the street-network configuration and emission patterns on the cross-street concentration gradient and (b) a satisfactory performance with assumption of well-mixed concentrations within street-canyons for mean NOx (MNE of 39% and 22%; and NMB of −29% and − 7% for Code_Saturne and SinG, respectively)