Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

Authors:

Jingfeng Xiao

Publications

Qianlai Zhuang

Publications

Beverly Law

Publications

Dennis Baldocchi

Publications

Jiquan Chen

Publications

Andrew Richardson

Publications

Jerry Melillo

Publications

Kenneth Davis

Publications

David Hollinger

Publications

Sonia Wharton

Publications

Ram Oren

Publications

Asko Noormets

Publications

Marc Fischer

Publications

Shashi Verma

Publications

David Cook

Publications

Ge Sun

Publications

Steve McNulty

Publications

Steven Wofsy

Publications

Paul Bolstad

Profile Publications

Sean Burns

Publications

Peter Curtis

Publications

Bert Drake

Publications

Matthias Falk

Publications

David Foster

Publications

Lianhong Gu

Publications

Julian Hadley

Publications

Gabriel Katul

Publications

Marcy Litvak

Publications

Siyan Ma

Publications

Timothy Martin

Publications

Roser Matamala

Publications

Tilden Meyers

Publications

Russell Monson

Publications

William Munger

Publications

Walter Oechel

Publications

Kyaw Paw

Publications

Hans Schmid

Publications

Russell Scott

Publications

Gregory Starr

Publications

Andrew Suyker

Publications

MARGARET TORN

Publications

+36 more

Publication Type:

Journal Article

Year of Publication:

2011

Secondary Title:

Agricultural and Forest Meteorology

ISSN:

01681923

DOI:

10.1016/j.agrformet.2010.09.002

Pages:

60-69

Volume:

151

Year:

2011

Date:

1/2011

Abstract

More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr-1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr-1 over the period 2001–2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by \~20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.