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GEOPHYSICAL RESEARCH LETTERS,
VOL. 31,
L20506,
doi:10.1029/2004GL020915,
2004
Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes
Dev Niyogi
Department of MEAS, North Carolina State University, Raleigh, North Carolina, USA
Hsin-I Chang
Department of MEAS, North Carolina State University, Raleigh, North Carolina, USA
V. K. Saxena
Department of MEAS, North Carolina State University, Raleigh, North Carolina, USA
Teddy Holt
Department of MEAS, North Carolina State University, Raleigh, North Carolina, USA
Kiran Alapaty
University of North Carolina at Chapel Hill, Raleigh, North Carolina, USA
Fitzgerald Booker
USDA-ARS Air Quality–Plant Growth and Development Unit, Raleigh, North Carolina, USA
Fei Chen
National Center for Atmospheric Research, Boulder, Colorado, USA
Kenneth J. Davis
Department of Meteorology, Pennsylvania State University, University Park, Pennsylvania, USA
Brent Holben
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Toshihisa Matsui
Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, USA
Tilden Meyers
Atmospheric Turbulence and Diffusion Division, National Oceanic and Atmospheric Administration, Oak Ridge, Tennessee, USA
Walter C. Oechel
San Diego State University, San Diego, California, USA
Roger A. Pielke Sr.
Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, USA
Randy Wells
Department of Crop Science, North Carolina State University, Raleigh, North Carolina, USA
Kell Wilson
Atmospheric Turbulence and Diffusion Division, National Oceanic and Atmospheric Administration, Oak Ridge, Tennessee, USA
Yongkang Xue
Department of Geography, University of California, Los Angeles, Los Angeles, California, USA
Abstract
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.
Received 5
July
2004;
accepted 29
September
2004;
published 29
October
2004.
Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 1610 Global Change: Atmosphere (0315, 0325); 1615 Global Change: Biogeochemical processes (4805).
Read Full Article (file size: 206703 bytes) Cited by
Citation: Niyogi, D., et al.
(2004),
Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes,
Geophys. Res. Lett.,
31,
L20506,
doi:10.1029/2004GL020915.
Copyright 2004 by the American Geophysical Union.
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