INVESTIGADORES
DIEGUEZ Maria Del Carmen
congresos y reuniones científicas
Título:
On the Distribution of Atmospheric Mercury Species in the Tropics, and the North ? South Divide: results from GMOS measurements and models
Autor/es:
HEDGECOCK, I., SPROVIERI, F., PIRRONE, N., ; DIÉGUEZ, MC.,; GARCIA, PE., ; READ, KA., MENDES NEVES, L., ARTAXO, P., GONÇALVES MORAIS, F; GAWLIK, BM., SENA, F., RAMÍREZ ISLAS, M., ARCEGA CABRERA, F., WIP, D., TRAVNIKOV, O
Lugar:
Jeju
Reunión:
Congreso; 12th ICMGP; 2015
Institución organizadora:
ICMGP
Resumen:
The distribution of modern day anthropogenic Hg emissions has been until recently dominated by industrial and energy production activity in the northern hemisphere. This resulted in a noticeable difference in background Hg concentrations between the northern and southern hemispheres. The most recent global anthropogenic Hg emission inventory from AMAP/UNEP (2010), however differs from previous inventories in two major characteristics. The first is that coal combustion is no longer the dominant source of anthropogenic Hg to the atmosphere, but has been overtaken by artisanal and small scale gold mining (ASGM). This has implications for both the speciation of Hg emissions and the height of their release. The second is that the geographical distribution of anthropogenic emissions has shifted southwards as most ASGM occurs within the tropics, and away from industrial centres. The location of a number of the Global Mercury Observation System (GMOS) monitoring sites falls within or just outside the tropics, while others are at background southern hemisphere sites. In most instances the monitoring stations are situated in areas for which no previous measurement data is available. This provides an opportunity to test and refine atmospheric Hg models in an unprecedented manner. Preliminary results from global models are promising, the north-south difference in background atmospheric Hg concentrations seen in the results is reproduced in the models. A study, using a regional model over Europe and the Mediterranean, illustrates how the diminishing local emissions mean that long-range transport of atmospheric Hg is playing an increasing role in Hg deposition fluxes. This study also highlighted how the role of marine emissions is becoming proportionally more important on a regional scale. The role of re-emission of Hg from the world´s oceans is a major factor in determining atmospheric Hg concentrations, and can be a significant source of uncertainty in modelling studies. The coastal and island sites within GMOS are of particular importance therefore in constraining the ocean exchange flux of Hg. How the distribution of Hg emissions change in the future as economies expand or contract, and as the price of gold fluctuates is open to question. However the necessity of observations in tropical regions, and in particular the measurement data with which to compare model output is fundamental in estimating Hg loading to tropical seas and oceans which provide a vast number of resources to local communities.