Modelling atmospheric transport of α-hexachlorocyclohexane in the Northern Hemispherewith a 3-D dynamical model: DEHM-POP

[摘要] The Danish Eulerian Hemispheric Model (DEHM) is a 3-D dynamicalatmospheric transport model originally developed to describe theatmospheric transport of sulphur into the Arctic. A new version ofthe model, DEHM-POP, developed to study the atmospheric transportand environmental fate of persistent organic pollutants (POPs) ispresented. During environmental cycling, POPs can be deposited andre-emitted several times before reaching a final destination. Adescription of the exchange processes between the land/oceansurfaces and the atmosphere is included in the model to accountfor this multi-hop transport. The α-isomer of the pesticidehexachlorocyclohexane (α-HCH) is used as tracer in themodel development. The structure of the model and processesincluded are described in detail. The results from a modelsimulation showing the atmospheric transport for the years 1991 to1998 are presented and evaluated against measurements. The annualaveraged atmospheric concentration of α-HCH for the 1990sis well described by the model; however, the shorter-term averageconcentration for most of the stations is not well captured. Thisindicates that the present simple surface description needs to berefined to get a better description of the air-surface exchangeprocesses of POPs.

[学科分类] 大气科学