Open AccessThe impacts of changing transport and precipitation on pollutant distributions in a future climate
Author(s) -
Fang Yuanyuan,
Fiore Arlene M.,
Horowitz Larry W.,
Gnanadesikan Anand,
Held Isaac,
Chen Gang,
Vecchi Gabriel,
Levy Hiram
Publication year - 2011
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jd015642
Subject(s) - precipitation , environmental science , pollutant , climate change , atmospheric sciences , deposition (geology) , climatology , air pollution , particulates , climate model , ozone , pollution , troposphere , meteorology , chemistry , geology , geography , oceanography , organic chemistry , paleontology , ecology , sediment , biology
Air pollution (ozone and particulate matter in surface air) is strongly linked to synoptic weather and thus is likely sensitive to climate change. In order to isolate the responses of air pollutant transport and wet removal to a warming climate, we examine a simple carbon monoxide–like (CO) tracer (COt) and a soluble version (SAt), both with the 2001 CO emissions, in simulations with the Geophysical Fluid Dynamics Laboratory chemistry‐climate model (AM3) for present (1981–2000) and future (2081–2100) climates. In 2081–2100, projected reductions in lower‐tropospheric ventilation and wet deposition exacerbate surface air pollution as evidenced by higher surface COt and SAt concentrations. However, the average horizontal general circulation patterns in 2081–2100 are similar to 1981–2000, so the spatial distribution of COt changes little. Precipitation is an important factor controlling soluble pollutant wet removal, but the total global precipitation change alone does not necessarily indicate the sign of the soluble pollutant response to climate change. Over certain latitudinal bands, however, the annual wet deposition change can be explained mainly by the simulated changes in large‐scale (LS) precipitation. In regions such as North America, differences in the seasonality of LS precipitation and tracer burdens contribute to an apparent inconsistency of changes in annual wet deposition versus annual precipitation. As a step toward an ultimate goal of developing a simple index that can be applied to infer changes in soluble pollutants directly from changes in precipitation fields as projected by physical climate models, we explore here a “Diagnosed Precipitation Impact” (DPI) index. This index captures the sign and magnitude (within 50%) of the relative annual mean changes in the global wet deposition of the soluble pollutant. DPI can only be usefully applied in climate models in which LS precipitation dominates wet deposition and horizontal transport patterns change little as climate warms. Our findings support the need for tighter emission regulations, for both soluble and insoluble pollutants, to obtain a desired level of air quality as climate warms.