Effects of Serial Dependence and Large-Scale Tropospheric Circulation on Midlatitude North American Terrestrial Carbon Dioxide Exchange

• Main Authors: Robbie A. Hember, Peter M. Lafleur
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2006
• Subjects: Pacific; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.511.7969; http://flux.aos.wisc.edu/twiki/pub/Main/WetlandPapers/i1520-0442-21-4-751.pdf

Linear regression was used to relate modes of tropospheric circulation variability to estimates of gross ecosystem production (GEP) and ecosystem respiration (ER) measured at 14 midlatitude North American eddy covariance (EC) towers. The North Atlantic Oscillation (NAO) exhibited a north–south gradient in its effect on fluxes, with negative influence on fluxes at central and northeastern stations and positive influence on fluxes at southeastern stations. During spring, average values of GEP and ER within the northern “cold ” sector decreased by 22 and 12 g C m2 (18 % and 11%), respectively, in response to a unit increase (1 standard deviation) in the expansion coefficient of the NAO mode. Despite a northward advancement of the “warm ” sector during summer, GEP and ER remained negatively correlated with the NAO at northern stations, decreasing on average by 48 and 30 g C m2 (8 % and 6%), respectively. During spring, the North Pacific Oscillation (NPO) reduced GEP and ER at central and northeastern stations on average by 20 and 7 g C m2 (16 % and 6%) and increased GEP and ER at southern and west coast stations on average by 53 and 49 g C m2 (12 % and 17%) in response to a unit increase in the NPO. This pattern persisted into summer, only shifted northward, with flux decreases of 19 and 24 g C m2 (3 % and 5%) at northern stations and increases of 72 and 82 g C m2 (9 % and 16%) at central stations. The direction of the