HYSPLIT Dispersion Model Research Articles

Levels and chemical composition of PM in a city near a large Cu-smelter in Spain

A long-term series (2001-2008) of chemical analysis of atmospheric particulate matter (PM(10) and PM(2.5)) collected in the city of Huelva (SW Spain) is considered in this study. The impact of emission plumes from one of the largest Cu-smelters in the world on air quality in the city of Huelva is evidenced by the high daily and hourly levels of As, other potentially toxic elements (e.g. Cu, Zn, Cd, Se, Bi, and Pb) in particulate matter, as well as the high levels of some gaseous pollutants (NO(2) and SO(2)). Mean arsenic levels in the PM10 fraction were higher than the target value set by European Directive 2004/107/EC (6 ngAs m(-3)) for 1(st) January 2013. Hourly peak concentrations of As and other metals and elements (Zn, Cu, P and Se) analyzed by PIXE can reach maximum hourly levels as high as 326 ngAs m(-3), 506 ngZn m(-3), 345 ngCu m(-3), 778 ngP m(-3) and 12 ngSe m(-3). The contribution of Cu-smelter emissions to ambient PM is quantified on an annual basis in 2.0-6.7 µg m(-3) and 1.8-4.2 µg m(-3) for PM(10) and PM(2.5), respectively. High resolution outputs of the HYSPLIT dispersion model show the geographical distribution of the As ambient levels into the emission plume, suggesting that the working regime of the Cu-smelter factory and the sea breeze circulation are the main factors controlling the impact of the Cu-smelter on the air quality of the city. The results of this work improve our understanding of the behaviour of industrial emission plumes and their impact on air quality of a city, where the population might be exposed to very high ambient concentrations of toxic metals during a few hours.

A simulation study of short-range atmospheric dispersion for hypothetical air-borne effluent releases using different turbulent diffusion methods

Radiological impact due to hypothetical air-borne effluent releases for an upcoming fast reactor (PFBR), at a tropical coastal site in Kalpakkam is studied using the HYSPLIT dispersion model. Short range air dispersion simulations are conducted with HYSPLIT for a weakly forced synoptic condition on 3rd March, 2008 with three turbulent diffusion methods, i.e., standard velocity deformation (A), short range isotropic similarity (B) and turbulent kinetic energy (TKE) (C) schemes to assess their performance in predicting the dose distribution at a local scale. The time varying 3-d meteorological parameters for the case study are predicted using a nested grid meso-scale dynamical atmospheric model MM5. Results indicate that the velocity deformation method gives spatially more complex dose pattern while the short-range similarity and TKE methods provide smoother horizontal dose profiles. The downwind dose in different pathways due to elevated releases is found to be the highest for the method A followed by B and C. For the ground releases, the TKE method produced higher doses than the other two. The difference in the dose values from the three methods is due to the variation in the horizontal and vertical mixing calculation and the assumptions involved in the respective methods. The total dose at the site boundary from different pathways is highest from the TKE method. Values from all the methods are about one to two orders less than the values given by a Gaussian Plume model for similar atmospheric conditions. The total dose estimated from the TKE method is 20.62 mSv at the release location and 1.25 mSv at the site boundary.

Atmospheric trajectories and spring bird migration across the Gulf of Mexico

We examined the relationship between the longitude of peak arrival of trans-Gulf migrants on the northern coast of the Gulf of Mexico in spring and wind trajectories over the Gulf at three different altitudes (500, 1,500, and 2,500 m above ground level). We used data from 10 WSR-88D radars (weather surveillance radar-1988-Doppler) from Brownsville, Texas, to Key West, Florida, to record the time and longitude of peak arrival on the northern Gulf coast for four spring migrations (2001–2004). We used the National Oceanic Atmospheric Administration Air Resources Laboratory HYSPLIT transport and dispersion model at the READY Web site to generate backward, 24-h atmospheric trajectories based on archived atmospheric data for each trans-Gulf flight. The trajectories began at the geographic location where radar indicated the greatest concentrations of arriving migrants. Although the longitude of peak arrival varied, peak densities of most trans-Gulf migrants arrived on the northern coast near longitude 95°W. Regression analyses showed that the relationship between the longitude of peak trans-Gulf arrival and the direction of atmospheric trajectory was significant but weak at the 500-m level, where few migrants occurred, and was insignificant for the 1,500- and 2,500-m altitudes, where migrant densities were greater. We conclude that winds aloft over the Gulf have little influence on the longitude of peak trans-Gulf arrival on the northern coast of the Gulf of Mexico, and we speculate that the arrival pattern may reflect the trans-Gulf migration pathways that evolved during the Last Glacial Maximum.