Abstract: The Minamata Convention on Mercury was established to reduce the pressure on the environment caused by mercury by significantly reducing its emissions from anthropogenic activities. However, knowledge gaps still exist concerning emission inventories, emission factors and their integration in modelling frameworks. In addition, tools to facilitate communication between decision-makers and research groups providing measurement and modelling data are still scarce. This work presents the GOS4M Knowledge Hub, a public web application that provides an interactive and user friendly experience to access state-of-the-art modelling tools and data available in the literature. The Knowledge Hub currently integrates a Chemical Transport Model emulator, HERMES, coupled with a biogeochemical model, although it has been designed to house and deploy any number of different modelling components. Using the integrated dashboard, non-experts can perturb mercury releases from different anthropogenic emission sectors, simulating, for example, the application of Best Available Technologies, and then visualise in real-time the short- and long-term effects of the consequent reductions within a source-receptor framework. The dashboard also furnishes an estimate of the statistical significance of the changes in the model results. The analysis of a set of anthropogenic Hg emission reduction scenarios shows how an internationally coordinated effort would be necessary to achieve significant policy goals. It is important to note that the GOS4M Knowledge Hub yields the analysis presented here in a matter of seconds, compared to the days or weeks required by traditional modelling tools.
Abstract: Implementation of the Minamata Convention on Mercury requires all parties to control, and where feasible, reduce mercury (Hg) emissions from a convention-specified set of sources. However, the convention does not specify the extent of the measures to be adopted, which may only be analysed by decision-makers using modelled scenarios. Currently, the numerical models available to study the Hg atmospheric cycle require significant expertise and high-end hardware, with results which are generally available on a time frame of days to weeks. In this work we present HERMES, a statistical emulator built on the output of a global Chemical Transport Model (CTM) for Hg (ECHMERIT), to simulate changes in anthropogenic Hg (Hganthr) deposition fluxes in a source-receptor framework, due to perturbations to Hganthr emissions and the associated statistical significance of the changes. The HERMES emulator enables stakeholders to evaluate the implementation of different Hganthr emission scenarios in an interactive and real-time manner, simulating the application of the different Best Available Technologies. HERMES provides the scientific soundness of a full CTM numerical framework[...]
Abstract: Establishing mercury (Hg) source-receptor (SR) relationship matrices provides a tool to improve the understanding of the geographic relationship between regions of Hg release and its eventual deposition. SR relationship matrices are therefore a useful starting point for the development of policies aimed at reducing the impact of Hg emissions from anthropogenic activities (Hganthr) on sensitive ecosystems and areas potentially at risk of Hg contamination. A global Chemical Transport Model (CTM) has been used to simulate the emission, transport and fate of Hganthr from 12 source regions, considering a range of uncertainty in the modelled chemical and physical processes. This ensemble of simulations gives an estimate of the Hg deposition which derives from each source region, as well as an estimate of the uncertainty of the calculated deposition flux. The uncertainty has been calculated using the bootstrap method to estimate this uncertainty in terms of the normalised confidence interval amplitude of the mean (NCIAM). Within the calculated confidence ranges, for almost all regions the contribution to the Hg deposition flux from remote sources is greater than that from domestic sources. Europe and South[...]
Abstract: The Minamata Convention on Mercury is an international treaty with the objective of protecting human health by controlling and restricting mercury use and its release to the environment. Numerical modeling tools currently used to study the fate of mercury released to the atmosphere tend to answer questions such as ’what would be the result of a 50% decrease in mercury emissions from this region, or that emission sector?’. They are not generally designed to answer the questions of the type, ’How can a, say 25% reduction, in deposition be achieved for a particular terrestrial ecosystem/region or oceanic basin?’. This paper presents an optimization framework which exploits the numerical tractability and the real-time features of an emulator for Global Chemical Transport Mercury Models. The HERMES emulator uses the results of a large number of scenario simulations to provide the user in real-time the impact on mercury deposition resulting from changes in anthropogenic mercury emissions. The changes in emissions can be by emission sector, emission region or changes in the speciation of the emissions. The optimization framework extends the capabilities of the emulator to give the user the possibility to define a deposition reduction target in one or more regions, and the framework calculates the optimal set of emissions reductions from industrial macro-sectors considering all the geographical source regions. The user may set a maximum feasible emission reduction in each of the sectors or regions, and within these constraints the optimization framework calculates the minimum number of regions in which the emission abatement would need to be applied to achieve the target, or informs the user that the desired target is unattainable with the supplied constraints. The results from the case-study presented here not only demonstrate the need for action to implement the Convention to be concerted and coordinated internationally, but also the usefulness of an optimization framework to tailor policies for specific environmental targets.
Abstract: The atmospheric deposition of mercury (Hg) oc- curs via several mechanisms, including dry and wet scaveng- ing by precipitation events. In an effort to understand the at- mospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Interannual differ- ences in total wet deposition are mostly linked with precipi- tation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions such as the South- ern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous mea- surements across the GMOS network as well as new findings in future modeling studies.
Abstract: The overall goal of the on-going Global Mercury Observation System (GMOS) project is to develop a coordinated global monitoring network for mercury, including ground-based, high altitude and sea level stations. In order to ensure data reliability and comparability, a significant effort has been made to implement a centralized system, which is designed to quality assure and quality control atmospheric mercury datasets. This system, GMOS-Data Quality Management (G-DQM), uses a web-based approach with real-time adaptive monitoring procedures aimed at preventing the production of poor-quality data. G-DQM is plugged on a cyberinfrastructure and deployed as a service. Atmospheric mercury datasets, produced during the first-three years of the GMOS project, are used as the input to demonstrate the application of the G-DQM and how it identifies a number of key issues concerning data quality. The major issues influencing data quality are presented and discussed for the GMOS stations under study. Atmospheric mercury data collected at the Longobucco (Italy) station is used as a detailed case study
Abstract: Long-term monitoring of data of ambient mercury (Hg) on a global scale to assess its emission, transport, atmo- spheric chemistry, and deposition processes is vital to under- standing the impact of Hg pollution on the environment. The Global Mercury Observation System (GMOS) project was funded by the European Commission (http://www.gmos.eu) and started in November 2010 with the overall goal to de- velop a coordinated global observing system to monitor Hg on a global scale, including a large network of ground-based monitoring stations, ad hoc periodic oceanographic cruises and measurement flights in the lower and upper troposphere as well as in the lower stratosphere. To date, more than 40 ground-based monitoring sites constitute the global net- work covering many regions where little to no observational data were available before GMOS. This work presents atmo- spheric Hg concentrations recorded worldwide in the frame- work of the GMOS project (2010–2015), analyzing Hg mea- surement results in terms of temporal trends, seasonality and comparability within the network. Major findings high- lighted in this paper include a clear gradient of Hg concentra- tions between the Northern and Southern hemispheres, con- firming that the gradient observed is mostly driven by local and regional sources, which can be anthropogenic, natural or a combination of both.