Proposed course of study in general science for non-college preparatory students

This item was digitized by the Internet Archive. Thesis (Ed.M.)--Boston Universit

Seeking for the Rational Basis of the Median Model: The Optimal Combination of Multi-model ENSEMBLE Results

In this paper we present an approach for the statistical analysis of multi-model ENSEMBLE results. The models considered here are operational long-range transport and dispersion models, also used for the real-time simulation of pollutant dispersion or the accidental release 5 of radioactive nuclides. We first introduce the theoretical basis (with its roots sinking into the Bayes theorem) and then apply this approach to the analysis of model results obtained during the ETEX-1 exercise. We recover some interesting results, supporting the heuristic approach called ‘median model’, originally introduced in Galmarini et al., 2004 a,b. This approach also provides a way to systematically reduce (and quantify) model uncertainties, thus supporting the decision-making process and/or regulatory-purpose activities in a very effective manner.JRC.H.4-Transport and air qualit

Modeling the transport of Saharan dust toward the Mediterranean region: an important issue for its ecological implications

Airborne particulate matter (PM) is presently an environmental problem of primary concern, whose role in air quality, climatic and ecological issues is well recognized, though still a matter of extensive investigations (Intergovernmental Panel on Climate Change, 2007).It is of great scientific interest to detect sources of atmospheric particulate matter and quantify their influence on the global and local scales. Unfortunately, emissions are usually not directly available, while PM concentration time series are experimentally accessible, so that the problem often consists in "inverting" these data to determine the region of influence that caused the measured concentration. In this paper we are concerned with an alternative approach to inverse modeling based on backward trajectory analysis (BTA); this approach has the potential to overcome some limitations associated with traditional BTA.We apply this method to the analysis of PM time series from the Monte Cimone observatory, hereafter MCT, a high altitude station on the top of the Italian Northern Apennines, with the aim of estimate the contribution of Saharan dust transport on PM concentration levels registered in the Mediterranean region

Seasonal variation of size-resolved aerosol fluxes in a Peri-urban deciduous broadleaved forest

Eddy covariance measurements of aerosol fluxes were performed above an oak-hornbeam forest in the Po Plain (Northern Italy), from February to May and from September to December 2019. Measurements aimed at assessing the influence of forest phenology and leaf presence/absence on the seasonal evolution of size-segregated aerosol fluxes. The size-resolved aerosol concentration in the range 0.006-10 μm was sampled with a 14-stage impactor (ELPI+, Dekati, FI), and the filters exposed in May were subjected to chemical analysis. Over the whole sampling period, the forest removed from the atmosphere an average of 3.12 mg of aerosol m−2 d−1. The direction and the intensity of the aerosol fluxes were not constant through the year, as a strong seasonal and size-dependent variability emerged. In particular, leaf-presence drove a net deposition of the accumulation mode aerosol (100 nm< particle diameter Dp<1000 nm) and an emission of the Aitken (10 nm< Dp<100 nm) and coarse mode (Dp>1000 nm) aerosols. On the contrary, in absence of leaves all the sub-micrometer aerosol size-classes showed net daily upward fluxes, while coarse mode aerosol fluxes were prevalently downward. Monthly averages of deposition velocities of Aitken and accumulation mode aerosols correlated with the Leaf Area Index (LAI) seasonal trend, thus indicating an important role of the amount of the leaf surface area on the deposition and emission of these size-classes. Furthermore, an influence of the stomatic activity was suggested for the Aitken mode aerosol, since its deposition velocity followed the same diel course of the stomatal conductance to water. The analysis of the influence of meteorological parameters on aerosol deposition velocities highlighted that dynamic and convective turbulence (described by friction velocity, u* and Deardorff velocity, w*) enhanced the vertical aerosol exchanges, both upward and downward, while the approaching of condensing conditions reduced the flux intensities

some remarks about a community open source lagrangian pollutant transport and dispersion model

Nowadays fishes and mussels farming is very important, from an economical point of view, for the local social background of the Bay of Naples. Hence, the accurate forecast of marine pollution becomes crucial to have reliable evaluation of its adverse effects on coastal inhabitants' health. The use of connected smart devices for monitoring the sea water pollution is getting harder because of the saline environment, the network availability and the maintain and calibration costs2. To this purpose, we designed and implemented WaComM (Water Community Model), a community open source model for sea pollutants transport and dispersion. WaComM is a model component of a scientific workflow which allows to perform, on a dedicated computational infrastructure, numerical simulations providing spatial and temporal high-resolution predictions of weather and marine conditions of the Bay of Naples leveraging on the cloud based31FACE-IT workflow engine27. In this paper we present some remarks about the development of WaComM, using hierarchical parallelism which implies distributed memory, shared memory and GPGPUs. Some numerical details are also discussed. Peer-review under responsibility of the Conference Program Chairs

Multi-aircraft environmentally-scored weather-resilient optimised 4D-trajectories

Weather phenomena are one of the biggest causes for significant delays and unpredictable disruptions within air traffic management (ATM) network operations. The changing global climate increases the future severity and frequency of these air traffic disturbing weather phenomena. This deteriorates the predictability of 4D trajectory ATM network planning and potentially increases the delays within air traffic operations. Furthermore, aviation itself has a responsibility to mitigate its climate impact to improve the long-term sustainability of the ATM operations and to contribute to the global effort towards the reduction of anthropogenic climate change. The SESAR2020 exploratory research project CREATE (Grant 890898) aims to find answers on how to improve the weather-resilience of ATM-operations and to reduce its climate impact. A concept of operations (ConOps) has been developed which describes an integrated trajectory optimisation framework to tactically define environmentally-scored optimised 4D trajectories, for a multi-aircraft airspace configuration, using advanced numerical weather prediction models, combined with air traffic control (ATC) driven demand-capacity balancing methods. The framework will be applied to an en-route use-case focusing on the unorganised traffic over the North Atlantic, and a Terminal Manoevring Area (TMA) use-case focusing on the Naples Capodichino airspace. The optimised trajectories aim to evade thunderstorms and contrail formation regions, whilst minimising CO2, non-CO2 and local air quality (LAQ) impacts.This project has received funding within the framework of the SESAR Joint Undertaking project “Innovative Operations and Climate and Weather Models to Improve ATM Resilience and Reduce Impacts” (SESARH2020-ER4 CREATE) within the European Union's Horizon 2020 research and innovation programme under grant agreement No 890898. The CREATE consortium is formed by ATM/Meteo/Environmental specialists from the Royal Netherlands Aerospace Centre (NLR), Universitat Politècnica de Catalunya (UPC), Centro Italiano Ricerche Aerospaziali (CIRA), Università degli Studi di Napoli Parthenope (UNIPARTH, project coordinator), ARIANET, Ilmatieteen Laitos (Finnish Meteorological Institute, FMI), and Institute for Sustainable Society and Innovation (ISSNOVA).Peer ReviewedPostprint (published version

CO2 and non-CO2 balanced environmental scores module for flight performance evaluation and optimisation

The SESAR2020 exploratory research (ER4) programme CREATE (Grant 890898) developed a climate and weather aware Concept of Operations (ConOps) which encompasses a multi-aircraft 4D trajectory optimisation framework, which utilises a CO2 and non-CO2 balanced Environmental Scores Module (ESM) for the en-route flight phase. The ESM provides a computational method to evaluate the “greenness” of aircraft trajectories. Some components related to the internal ESM scoring are based on expert judgement, which is in line with the technology readiness level (TRL) 1 of the solution. Fast-time simulations were performed to demonstrate the proof-of-concept of the ESM in a multi-aircraft tactical optimisation scenario in the North-Atlantic region. The results show that, because of the simplicity of the metric, the ESM could be well used for trajectory optimisation and tactical replanning, and most likely as well as flight and ATC sector environmental performance evaluations.The work presented in this paper has received funding from the SESAR Joint Undertaking (JU) under grant agreement No 890898, corresponding to the project “Innovative Operations and Climate and Weather Models to Improve ATM Resilience and Reduce Impacts” (SESAR-H2020-ER4 CREATE) within the European Union's Horizon 2020 research and innovation program.Peer ReviewedPostprint (published version

Alternative 4D trajectories for the avoidance of weather- and contrail-sensitive volumes

We present a framework to generate, in a multi-aircraft environment, 4D optimized trajectories in a scenario with several weather constraints obtained with advanced weather prediction models. We focus on the trajectory optimization module of this framework, which is based on a point-mass representation of the aircraft. By tuning some of the parameters of this module, we compute several alternative trajectories avoiding these constraints both laterally and vertically. The experiment conducted involves flights crossing the North Atlantic region, while in the en-route phase. This preliminary framework is also used to run the experiments in multiple cycles or consecutive time periods, assuming different update times for the weather constraints, and choosing the best trajectory per flight and per cycle. The ultimate goal of the framework is to develop innovative procedures in the air traffic management system to reduce the climate and environmental impact of aviation, while increasing the resilience of air operations to weather phenomena.Peer ReviewedPostprint (published version

delta C-13 signatures of organic aerosols:Measurement method evaluation and application in a source study

Analysis of the stable carbon isotope 13C in organic carbon (OC) can give insight into sources and atmospheric processing of carbonaceous aerosols, provided the 13C source signatures are known. However, only few data on 13C signatures of OC emitted by common sources of carbonaceous aerosol are available in Europe. We present and evaluate an improved version of a measurement method to obtain δ13C signatures on organic aerosols desorbed from filter samples at three different desorption temperatures (200 °C, 350 °C and 650 °C) and apply it in a source study. With our calibration approach, the reproducibility of a L-Valine reference material desorbed at a single temperature step of 650 °C shows a standard deviation of 0.19‰ over a period of more than one year. The average δ13C value for this reference material over 248 measurements is −24.10‰, which shows only a slight bias to the nominal value of −24.03‰. Repeated analysis of ambient filter samples desorbed at three temperature steps show typical standard deviations of about 0.3‰ for all temperature steps (200 °C, 350 °C and 650 °C). Isotopic fractionation due to partial thermal desorption during the individual temperature steps was tested on single compound reference materials. It showed significant isotopic fractionation only at temperature steps, in which a very minor fraction of the compound was desorbed. Possible isotope effects caused by charring of organic material were investigated and found to be not significant. The thermal desorption method was applied to various source filter samples from the region of Naples, Italy. We analyzed two different biomass burning sources, exhaust from a city bus and traffic emissions collected in a tunnel and compared these to ambient filter samples from the same region. δ13C signatures of the total OC show values in a narrow range of about −28‰ to −26‰ for all sources, which does not allow a source apportionment only based on 13C. Nevertheless, the results add information to a source inventory of δ13C, where information of 13C in organic aerosol from specific emission sources are rare. City bus emissions show little variation of δ13C over the temperature steps, whereas biomass burning aerosol is enriched in 13C for OC desorbed at 650 °C. For PM10 samples in the urban tunnel an enrichment in δ13C at the 650 °C temperature steps was observed, which is likely caused by the contribution of carbonate carbon to the carbonaceous material desorbed at this temperature step