ORCID Profile
0000-0003-3881-9065
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Publisher: Copernicus GmbH
Date: 31-10-2016
Abstract: Abstract. OzFlux is the regional Australian and New Zealand flux tower network that aims to provide a continental-scale national research facility to monitor and assess trends, and improve predictions, of Australia's terrestrial biosphere and climate. This paper describes the evolution, design, and current status of OzFlux as well as provides an overview of data processing. We analyse measurements from all sites within the Australian portion of the OzFlux network and two sites from New Zealand. The response of the Australian biomes to climate was largely consistent with global studies except that Australian systems had a lower ecosystem water-use efficiency. Australian semi-arid/arid ecosystems are important because of their huge extent (70 %) and they have evolved with common moisture limitations. We also found that Australian ecosystems had a similar radiation-use efficiency per unit leaf area compared to global values that indicates a convergence toward a similar biochemical efficiency. The two New Zealand sites represented extremes in productivity for a moist temperate climate zone, with the grazed dairy farm site having the highest GPP of any OzFlux site (2620 gC m−2 yr−1) and the natural raised peat bog site having a very low GPP (820 gC m−2 yr−1). The paper discusses the utility of the flux data and the synergies between flux, remote sensing, and modelling. Lastly, the paper looks ahead at the future direction of the network and concludes that there has been a substantial contribution by OzFlux, and considerable opportunities remain to further advance our understanding of ecosystem response to disturbances, including drought, fire, land-use and land-cover change, land management, and climate change, which are relevant both nationally and internationally. It is suggested that a synergistic approach is required to address all of the spatial, ecological, human, and cultural challenges of managing the delicately balanced ecosystems in Australasia.
Publisher: Copernicus GmbH
Date: 28-04-2016
DOI: 10.5194/BG-2016-152
Abstract: Abstract. OzFlux is the regional Australian and New Zealand flux tower network that aims to provide a continental-scale national research facility to monitor and assess trends, and improve predictions, of Australia’s terrestrial biosphere and climate. This paper describes the evolution, design and current status of OzFlux as well as an overview of data processing. We analyse measurements from the Australian portion of the OzFlux network and found that the response of Australian biomes to climate was largely consistent with global studies but that Australian systems had a lower ecosystem water-use efficiency. Australian semi-arid/arid ecosystems are important because of their huge extent (70 %) and they have evolved with common moisture limitations. We also found that Australian ecosystems had similar radiation use efficiency per unit leaf area compared to global values that indicates a convergence toward a similar biochemical efficiency. The paper discusses the utility of the flux data and the synergies between flux, remote sensing and modelling. Lastly, the paper looks ahead at the future direction of the network and concludes that there has been a substantial contribution by OzFlux and considerable opportunities remain to further advance our understanding of ecosystem response to disturbances including drought, fire, land use and land cover change, land management and climate change that are relevant both nationally and internationally. It is suggested that a synergistic approach is required to address all of the spatial, ecological, human and cultural challenges of managing the delicately balanced ecosystems in Australia.
Publisher: Wiley
Date: 09-2013
Abstract: Synthetic fertilizer N additions to soils have significantly increased atmospheric NO concentrations, and advanced methods are needed to track the amount of applied N that is transformed to NO in the field. We have developed a method for continuous measurement of NO isotopologues (NNO, NNO, NNO, and NNO) following 0.4 and 0.8 g N m of N-labeled substrate as KNO or urea [CO(NH)] using Fourier-transform infrared (FTIR) spectroscopy. We evaluated this method using two 4-wk experimental trials on a coastal floodplain site near Nowra, New South Wales, Australia, which is managed for silage production. We deployed an automated five-chamber system connected to a portable FTIR spectrometer with multipass cell to measure NO isotopologue fluxes. Emissions of all isotopologues were evident immediately following N addition. All isotopologues responded positively to rainfall events, but only for 7 to 10 d following N addition. Cumulative N-NO fluxes (sum of the three N isotopologues) per chamber for the 14 d following N addition ranged from 1.5 to 10.3 mg N m. Approximately 1% (range 0.7-1.9%) of the total amount of N applied was emitted as NO. Repeatability (1σ) for all isotopologue measurements was better than 0.5 nmol mol for 1-min average concentration measurements, and minimum detectable fluxes for each isotopologue were <0.1 ng N m s. The results indicate that the portable FTIR spectroscopic technique can effectively trace transfer of N to the atmosphere as NO after N addition, allowing powerful quantification of NO emissions under field conditions.
No related grants have been discovered for Rebecca Phillips.