HR: 1340h
AN: A43A-0033    [Abstracts]
TI: ENSO-mediated climate-tree growth relationships in the southeastern United States
AU: * Anchukaitis, K J
EM: kanchuka@ltrr.arizona.edu
AF: Laboratory of Tree-Ring Research, The University of Arizona, Tucson, AZ 85721 United States
AU: * Anchukaitis, K J
EM: kanchuka@ltrr.arizona.edu
AF: Department of Geosciences, The University of Arizona, Tucson, AZ 85721 United States
AU: Evans, M N
EM: mevans@ltrr.arizona.edu
AF: Laboratory of Tree-Ring Research, The University of Arizona, Tucson, AZ 85721 United States
AU: Evans, M N
EM: mevans@ltrr.arizona.edu
AF: Department of Geosciences, The University of Arizona, Tucson, AZ 85721 United States
AU: Evans, M N
EM: mevans@ltrr.arizona.edu
AF: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AU: Vaganov, E A
EM: eavaganov@forest.akadem.ru
AF: Institute of Forest, Russian Academy of Sciences, Krasnoyarsk, 660036 Russian Federation
AU: Grissino-Mayer, H D
EM: grissino@utk.edu
AF: Department of Geography, The University of Tennessee, Knoxville, TN 35720 United States
AU: Hughes, M K
EM: mhughes@ltrr.arizona.edu
AF: Laboratory of Tree-Ring Research, The University of Arizona, Tucson, AZ 85721 United States
AU: Kaplan, A
EM: alexeyk@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AU: Cane, M A
EM: mcane@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AU: Cane, M A
EM: mcane@ldeo.columbia.edu
AF: Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027 United States
AB: We use a mechanistic model of tree-ring formation to evaluate the cause of a shift in climate-tree growth relationships observed after 1976 in the southeastern United States. Principal component analysis demonstrates that the leading EOFs of our simulated (n=8) and real (n=10) chronologies are well correlated (r=0.61, p$<$0.0001) and that the model has substantial skill in reproducing actual regional patterns of tree growth as controlled by climate. Modeled growth rates show a shift toward greater sensitivity to summer drought after 1976. This simulated regional response is consistent with that of our actual tree-ring data from North Carolina. After 1976, narrow ring width years in both our actual and simulated tree-ring series are associated with ENSO warm phase-like anomalies in Pacific sea surface temperatures. These results collectively suggest that summer drought, associated with more frequent ENSO activity, has become an important control on forest growth in the region since the mid-1970s.
DE: 3337 Numerical modeling and data assimilation
DE: 3344 Paleoclimatology
DE: 3309 Climatology (1620)
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting