Open AccessAnthropogenic and natural contributions to regional trends in aerosol optical depth, 1980–2006
Author(s) -
Streets David G.,
Yan Fang,
Chin Mian,
Diehl Thomas,
Mahowald Natalie,
Schultz Martin,
Wild Martin,
Wu Ye,
Yu Carolyne
Publication year - 2009
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 - 10.1029/2008jd011624
Subject(s) - aerosol , environmental science , volcano , air quality index , climatology , natural (archaeology) , east asia , storm , geography , physical geography , atmospheric sciences , meteorology , geology , china , archaeology , seismology
Understanding the roles of human and natural sources in contributing to aerosol concentrations around the world is an important step toward developing efficient and effective mitigation measures for local and regional air quality degradation and climate change. In this study we test the hypothesis that changes in aerosol optical depth (AOD) over time are caused by the changing patterns of anthropogenic emissions of aerosols and aerosol precursors. We present estimated trends of contributions to AOD for eight world regions from 1980 to 2006, built upon a full run of the Goddard Chemistry Aerosol Radiation and Transport model for the year 2001, extended in time using trends in emissions of man‐made and natural sources. Estimated AOD trends agree well ( R > 0.5) with observed trends in surface solar radiation in Russia, the United States, south Asia, southern Africa, and East Asia (before 1992) but less well for Organization for Economic Co‐operative Development (OECD) Europe ( R < 0.5). The trends do not agree well for southeast Asia and for East Asia (after 1992) where large‐scale inter‐ and intraannual variations in emissions from forest fires, volcanic eruptions, and dust storms confound our approach. Natural contributions to AOD, including forest and grassland fires, show no significant long‐term trends (<1%/a), except for a small increasing trend in OECD Europe and a small decreasing trend in South America. Trends in man‐made contributions to AOD follow the changing patterns of industrial and economic activity. We quantify the average contributions of key source types to regional AOD over the entire time period.