HR: 0800h
AN: U31C-0501    [Abstracts]
TI: Impacts of large-scale oscillations on northern high-latitude terrestrial net primary production
AU: * Zhang, K
EM: zhang@ntsg.umt.edu
AF: Flathead Lake Biological Station, the University of Montana, 32125 Bio Station Lane, Polson, MT 59860-9659, United States
AU: * Zhang, K
EM: zhang@ntsg.umt.edu
AF: Numerical Terradynamic Simulation Group, the University of Montana, 32 Campus Drive #1224, Missoula, MT 59812-1224, United States
AU: Kimball, J S
EM: johnk@ntsg.umt.edu
AF: Flathead Lake Biological Station, the University of Montana, 32125 Bio Station Lane, Polson, MT 59860-9659, United States
AU: Kimball, J S
EM: johnk@ntsg.umt.edu
AF: Numerical Terradynamic Simulation Group, the University of Montana, 32 Campus Drive #1224, Missoula, MT 59812-1224, United States
AU: McDonald, K C
EM: kyle.mcdonald@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 300-233, 4800 Oak Grove Drive, Pasadena, CA 91101, United States
AU: Cassano, J J
EM: John.Cassano@Colorado.EDU
AF: Cooperative Institute for Research in Environmental Sciences and Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309-0216,
AU: Running, S W
EM: swr@ntsg.umt.edu
AF: Numerical Terradynamic Simulation Group, the University of Montana, 32 Campus Drive #1224, Missoula, MT 59812-1224, United States
AB: We derived annual time series of vegetation net primary production (NPP) and growing season dynamics for the pan-Arctic basin and Alaska from 1983-2005. We used the MOD17A2/A3 production efficiency model driven by satellite based monthly leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR) from NOAA AVHRR Pathfinder and NASA EOS MODIS records, with gridded daily surface meteorology developed from a regional correction of the NCEP/NCAR reanalysis and NASA Solar Radiation Budget daily shortwave solar radiation inputs to compute NPP on a grid cell by cell basis across the domain. Analyses of regional climate oscillations and satellite derived NPP and growing season dynamics for the pan-Arctic region indicate that the oscillations influence NPP by regulating seasonal patterns of low temperature and moisture constraints to photosynthesis. Early-spring (Feb-Apr) patterns of the Arctic Oscillation (AO) are proportional to growing season onset (r=-0.653; P=0.001), while growing season patterns of the Pacific Decadal Oscillation (PDO) are proportional to the supply of plant-available moisture for NPP (r=-0.471; P=0.023). Relatively strong, negative PDO phases from 1988-1991 and 1998-2002 coincided with prolonged regional droughts indicated by a standardized moisture stress index. These severe droughts resulted in widespread reductions in NPP, especially for relatively drought prone boreal ecosystems. The influence of AO and PDO patterns on northern high-latitude vegetation productivity appears to be decreasing and increasing, respectively, as low temperature constraints to plant growth relax and NPP becomes increasingly limited by available water supply under a warming climate. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1640 Remote sensing (1855)
SC: Union [U]
MN: 2007 Fall Meeting