An atmospheric perspective on North American carbon dioxide exchange: CarbonTracker.
We present an estimate of net CO(2) exchange between the terrestrial biosphere and the atmosphere across North America for every week in the period 2000 through 2005. This estimate is derived from a set of 28,000 CO(2) mole fraction observations in the global atmosphere that are fed into a state-of-the-art data assimilation system for CO(2) called CarbonTracker. By design, the surface fluxes produced in CarbonTracker are consistent with the recent history of CO(2) in the atmosphere and provide constraints on the net carbon flux independent from national inventories derived from accounting efforts. We find the North American terrestrial biosphere to have absorbed -0.65 PgC/yr (1 petagram = 10(15) g; negative signs are used for carbon sinks) averaged over the period studied, partly offsetting the estimated 1.85 PgC/yr release by fossil fuel burning and cement manufacturing. Uncertainty on this estimate is derived from a set of sensitivity experiments and places the sink within a range of -0.4 to -1.0 PgC/yr. The estimated sink is located mainly in the deciduous forests along the East Coast (32%) and the boreal coniferous forests (22%). Terrestrial uptake fell to -0.32 PgC/yr during the large-scale drought of 2002, suggesting sensitivity of the contemporary carbon sinks to climate extremes. CarbonTracker results are in excellent agreement with a wide collection of carbon inventories that form the basis of the first North American State of the Carbon Cycle Report (SOCCR), to be released in 2007. All CarbonTracker results are freely available at http://carbontracker.noaa.gov.
National Oceanic and Atmospheric Administration Earth System Research Laboratory, 325 Broadway R/GMD1, Boulder, CO 80305, USA. wouter.peters@noaa.gov
Wouter
W
Peters
Andrew R
AR
Jacobson
Colm
C
Sweeney
Arlyn E
AE
Andrews
Thomas J
TJ
Conway
Kenneth
K
Masarie
John B
JB
Miller
Lori M P
LM
Bruhwiler
Gabrielle
G
Pétron
Adam I
AI
Hirsch
Douglas E J
DE
Worthy
Guido R
GR
van der Werf
James T
JT
Randerson
Paul O
PO
Wennberg
Maarten C
MC
Krol
Pieter P
PP
Tans
D000383:Agriculture; D000388:Air / Q000032:analysis; D001272:Atmosphere / Q000032:analysis*; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis*; D018556:Crops, Agricultural / Q000378:metabolism; D004190:Disasters; D004784:Environmental Monitoring / Q000295:instrumentation*; D005390:Fires; D005579:Fossil Fuels; D017752:Greenhouse Effect; D006802:Human Activities; D009656:North America; D006109:Poaceae / Q000378:metabolism; D014197:Trees / Q000378:metabolism
D005579:Fossil Fuels; D002245:Carbon Dioxide