Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes

Dev Niyogi, Hsin I. Chang, V. K. Saxena, Teddy Holt, Kiran Alapaty, Fitzgerald Booker, Fei Chen, Kenneth J. Davis, Brent Holben, Toshihisa Matsui, Tilden Meyers, Walter C. Oechel, Roger A. Pielke, Randy Wells, Kell Wilson, Yongkang Xue

Research output: Contribution to journalArticlepeer-review

185 Scopus citations


We present the first direct, multisite observations in Support of the hypothesis that atmospheric aerosols affect the regional terrestrial carbon cycle. The daytime growing season (summer) CO2 flux observations from six sites (forest, grasslands, and croplands) with collocated aerosol and surface radiation measurements were analyzed for high and low diffuse radiation; effect of cloud cover; and effect of high and low aerosol optical depths (AOD). Results indicate that, aerosols exert a significant impact on net CO2 exchange, and their effect may be even more significant than that due to clouds. The response appears to be a general feature irrespective of the landscape and photosynthetic pathway. The CO2 sink increased with aerosol loading for forest and crop lands, and decreased for grassland. The cause for the difference in response between vegetation types is hypothesized to be canopy architecture.

Original languageEnglish (US)
Pages (from-to)L20506 1-5
JournalGeophysical Research Letters
Issue number20
StatePublished - Oct 28 2004
Externally publishedYes


  • 0305 Atmospheric composition and structure: Aerosols and particles (0345, 4801)
  • 0315 Atmospheric composition and structure: Biosphere/atmosphere interactions
  • 0325)
  • 0345 Atmospheric composition and structure: Pollution - Urban and regional (0305)
  • 1610 Global change: Atmosphere (0315
  • 1615 Global change: Biogeochemical processes (4805)

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences


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