HR: 1340h
AN: B33D-1573    [Abstracts]
TI: Vegetation and Climatic Controls on the Interannual Variability of Land Surface Energy Balances and Evapotranspiration Over an Oak-Savanna Ecosystem and an Annual Grassland
AU: * Ryu, Y
EM: yryu@nature.berkeley.edu
AF: Ecosystem Sciences Division, Department of Environmental Science, Policy and Management, 40 Hilgard Hall, Berkeley, CA 94720, United States
AU: Baldocchi, D D
EM: baldocchi@nature.berkeley.edu
AF: Ecosystem Sciences Division, Department of Environmental Science, Policy and Management, 40 Hilgard Hall, Berkeley, CA 94720, United States
AB: We report on a 6-year record of land surface energy balances and evapotranspiration (ET) measurements using the eddy covariance technique over an oak-savanna ecosystem (OS) and an annual grassland (AG) in California. Although two sites are just 2 km apart and received similar solar radiation, they revealed pronounced differences in net radiation, sensible heat flux and ET on an annual scale due to different phenological traits (i.e. live trees in summer at OS whereas dead grasses in summer at AG). Normalized ET (ETN, ET/ETeq) scaled with bulk surface conductance at both sites and ETN was higher for AG than OS on a monthly time scale. In contrast, annual ET was higher for OS than AG. The primary climatic driver for interannual variability of ET was precipitation and cloudiness in May and June. Annual ET at both sites decreased with annual solar radiation amount, indicating that these ecosystems are water-limited.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0476 Plant ecology (1851)
DE: 1719 Hydrology
DE: 1818 Evapotranspiration
SC: Biogeosciences [B]
MN: 2007 Fall Meeting