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ABSTRACT: Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes above 35 degrees N. Two distinct periods of increasing plant growth are apparent: 1982-1991 and 1992-1999, separated by a reduction from 1991 to 1992 associated with global cooling resulting from the volcanic eruption of Mt. Pinatubo in June 1991. The average May to September normalized difference vegetation index from 45 degrees N to 75 degrees N increased by 9% from 1982 to 1991, decreased by 5% from 1991 to 1992, and increased by 8% from 1992 to 1999. Variations in the normalized difference vegetation index were associated with variations in the start of the growing season of -5.6, +3.9, and -1.7 days respectively, for the three time periods. Our results support surface temperature increases within the same period at higher northern latitudes where temperature limits plant growth.
International Journal of Bioclimatology Biometeorology 12/2001; 45(4):184-90. · 2.25 Impact Factor
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M J Behrenfeld,
J T Randerson,
C R McClain,
G C Feldman, S O Los,
C J Tucker,
P G Falkowski,
C B Field,
R Frouin,
W E Esaias,
D D Kolber,
N H Pollack
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ABSTRACT: The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provides global monthly measurements of both oceanic phytoplankton chlorophyll biomass and light harvesting by land plants. These measurements allowed the comparison of simultaneous ocean and land net primary production (NPP) responses to a major El Niño to La Niña transition. Between September 1997 and August 2000, biospheric NPP varied by 6 petagrams of carbon per year (from 111 to 117 petagrams of carbon per year). Increases in ocean NPP were pronounced in tropical regions where El Niño-Southern Oscillation (ENSO) impacts on upwelling and nutrient availability were greatest. Globally, land NPP did not exhibit a clear ENSO response, although regional changes were substantial.
Science 04/2001; 291(5513):2594-7. · 31.20 Impact Factor
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ABSTRACT: Images are presented that show the mean and coefficient of variation of nine years (1981-1989) of NOAA AVHRR normalized difference vegetation index (NDVI) data for the growing season (July-October) in Africa, north of the equator. The variation in the growing season NDVI is represented by the coefficient of variation image that shows the large variation in the Sahelian growing season between years. It is concluded that these images illustrate some aspects of the perspective being brought to regional and continental scale processes by coarse resolution satellite sensors and the potential of these sensors to provide consistent, long-term datasets.
07/1991;
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XF2006306672.
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Global Change Biology. 8:722-735.
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Geophysical Research Letters. 29.
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Global Biogeochemical Cycles. 11:367-392.
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XF2006306670.
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D.A. Randall,
P. J. Sellers,
J. A. Berry,
D. A. Dazlich,
C. Zhang,
G. J Collatz,
A. S. Denning, S. O. Los,
C. B. Field,
I. Fung,
C. O. Justice,
C. J. Tucker
Journal of Climate. 9:738-763.
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M.J. Behrenfeld,
J.T. Randerson,
C.R. McClain,
G.C. Feldman, S.O. Los,
C.J. Tucker,
P.G. Falkowski,
C.B. Field,
R. Frouin,
W.E. Esaias,
D.D. Kolber,
N.H. Pollack
Science. 291(5513):2594-2597.