Carbon and water fluxes over a temperate Eucalyptus forest and a tropical wet/dry savanna in Australia: measurements and comparison with MODIS remote sensing estimates

摘要: Measurements over a period of 33 months are presented for the fluxes carbon, sensible heat and water vapour tropical wet/dry savanna in northern Queensland (Virginia Park), 38 cool temperate Eucalyptus forest southeast Australia (Tumbarumba), as part OzFlux network. Fluxes were measured using micrometeorological methods neural network analysis was used to fill gaps hourly flux time series. Productivity at Virginia Park is controlled by rainfall amount timing during wet season since this determines leaf area index (Lai) C4 grass understorey which varies greatly compared Lai trees. The lost 99 g C m � 2 July 2001‐March 2004 due failure 2002‐2003 when lowest 20th percentile. Net uptake carbon Tumbarumba 2510 from February 2001 March 2004, with annual productivity ranging 1060 year 1 normal 360 drought affected all eastern Australia. Annual matched evapotranspiration, indicating there no surface runoff or deep drainage our study. Trees both sites able extract within soil profile maintain transpiration above 2002‐2003. gross primary production (PG) two estimates Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data products. MOD15 algorithm overestimated factor but gave reasonable magnitudes seasonal variation savanna. At Tumbarumba, MOD17 excellent amplitude PG less satisfactory predicting phase variations. dry low-rainfall summer results other seasons. Most variance explained absorbed photosynthetically active radiation. Significantly improved predictions obtained modifying account potential evaporation antecedent 3 months, surrogate availability. # 2005 Elsevier B.V. All rights reserved.