176 research outputs found
Observed relationships between El Niño-Southern Oscillation, rainfall variability and vegetation and fire history on Halmahera, Maluku, Indonesia
No full textA temporally high-resolution palynological study of the uppermost section of core MD98-2180 from Kau Bay, Halmahera, Indonesia, provides a vegetation and fire record covering the last 250 years. The record is compared with the Maluku Rainfall Index, Southern Oscillation Index (SOI) and southern hemisphere winter sea surface temperatures (SST) for the central Pacific Ocean based on instrumental data, as well as reconstructions of the SOI and the central Pacific SST and historically recorded El Nino events. The results show that significant El Nino events are generally associated with increased representation of Dipterocarpaceae pollen, probably reflecting the mass-flowering of this taxon during El Nino-Southern Oscillation (ENSO) droughts, and elevated charcoal levels, reflecting a greater incidence of fires during these extremely dry periods, while humid phases show increased fern numbers. Our findings demonstrate that pollen records 'ecological' in scale can provide useful additional proxy records of ENSO events
The microscale cooling effects of water sensitive urban design and irrigation in a suburban environment
No full text© 2017, Springer-Verlag GmbH Austria. Prolonged drought has threatened traditional potable urban water supplies in Australian cities, reducing capability to adapt to climate change and mitigate against extreme. Integrated urban water management (IUWM) approaches, such as water sensitive urban design (WSUD), reduce the reliance on centralised potable water supply systems and provide a means for retaining water in the urban environment through stormwater harvesting and reuse. This study examines the potential for WSUD to provide cooling benefits and reduce human exposure and heat stress and thermal discomfort. A high-resolution observational field campaign, measuring surface level microclimate variables and remotely sensed land surface characteristics, was conducted in a mixed residential suburb containing WSUD in Adelaide, South Australia. Clear evidence was found that WSUD features and irrigation can reduce surface temperature (T s ) and air temperature (T a ) and improve human thermal comfort (HTC) in urban environments. The average 3 pm T a near water bodies was found to be up to 1.8 °C cooler than the domain maximum. Cooling was broadly observed in the area 50 m downwind of lakes and wetlands. Design and placement of water bodies were found to affect their cooling effectiveness. HTC was improved by proximity to WSUD features, but shading and ventilation were also effective at improving thermal comfort. This study demonstrates that WSUD can be used to cool urban microclimates, while simultaneously achieving other environmental benefits, such as improved stream ecology and flood mitigation.sponsorship: Ashley Broadbent was funded by the Cooperative Research Centre for Water Sensitive Cities. While at Arizona State University, Ashley Broadbent was supported by NSF Sustainability Research Network (SRN) Cooperative Agreement 1444758, NSF grant EAR-1204774, and NSF SES-1520803. Nigel Tapper and Andrew Coutts are funded by the Cooperative Research Centre for Water Sensitive Cities. The contribution of Matthias Demuzere is funded by the Flemish regional government through a contract as a FWO (Fund for Scientific Research) post-doctoral research fellow. We are indebted to all those who assisted during the Mawson Lakes field campaign: Darren Hocking, Emma White, Naim Daliri-Milani, Stephen Livesley, and Margaret Loughnan. Finally, a sincere thank you to the two anonymous reviewers who provided helpful suggestions and comments. (Cooperative Research Centre for Water Sensitive Cities, NSF Sustainability Research Network (SRN)|1444758, NSF|EAR-1204774, NSF|SES-1520803, Flemish regional government through a contract as a FWO (Fund for Scientific Research) post-doctoral research fellow, Directorate For Geosciences; Division Of Earth Sciences|1204774)status: Publishe
Urban Tethys-Chloris (UT&C v1.0)
No full text<p>Urban Tethys-Chloris (UT&C v1.0) is a mechanistic urban ecohydrological model combining principles of ecohydrological land surface modelling with urban canopy modelling. UT&C is a fully coupled energy and water balance model that calculates 2 m air temperature, 2 m humidity, and surface temperatures. It explicitly resolves biophysical and ecophysiological characteristics of ground vegetation, urban trees, and green roofs and models all urban water fluxes including evapotranspiration, canopy interception, infiltration, and soil moisture transport. UT&C accounts for variations in urban densities, building properties, and urban irrigation schemes. Hence, the model is able to account for the effects of different plant types on the urban climate and hydrology, as well as the effects of the urban environment on plant well-being and performance. UT&C is one of the first urban canyon parameterizations to include detailed ecohydrology. Its low computational demand allows for analyses spanning multiple years with an hourly time step, therefore, facilitating long-term and seasonal analysis.</p>
<p>The model development and validation is presented in:</p>
<p>Naika Meili, Gabriele Manoli, Paolo Burlando, Elie Bou-Zeid, Winston T.L. Chow, Andrew<br>
M. Coutts, Edoardo Daly, Kerry A. Nice, Matthias Roth, Nigel J. Tapper, Erik Velasco,<br>
Enrique R. Vivoni, and Simone Fatichi (2019). <strong>An urban ecohydrological model to quantify the effect of vegetation<br>
on urban climate and hydrology (UT&C v1.0)</strong>, <em>Geoscientific Model Development, under review</em></p>Data and codes are open and free for scientific and educational purposes but their use should comply with a fair use policy. Specifically, proper acknowledgment and citations should be given to the model and all data used in a peer reviewed publication.
For any questions, please contact Naika Meili ([email protected]) or Simone Fatichi ([email protected]).
The research was conducted at the Future Cities Laboratory at the Singapore-ETH Centre, which was established collaboratively between ETH Zurich and Singapore's National Research Foundation (FI370074016) under its Campus for Research Excellence and Technological Enterprise programme. GM was supported by the "The Branco Weiss Fellowship - Society in Science" administered by ETH Zurich. EV acknowledges a research fellowship granted by the Centre for Urban Greenery and Ecology of Singapore's National Parks Board
A spatial vulnerability analysis of urban populations during extreme heat events in Australian capital cities
No full textExtreme heat events pose a risk to the health of all individuals, especially the elderly and the chronically ill, and are associated with an increased demand for healthcare services.
In order to address this problem, policy makers need information about temperatures above which mortality and morbidity of the exposed population is likely to increase, where the vulnerable groups in the community are located, and how the risks from extreme heat events are likely to change in the future.
This study identified threshold temperatures for all Australian capital cities, developed a spatial index of population vulnerability, and used climate model output to predict changes in the number of days exceeding temperature thresholds in the future, as well as changes in risk related to changes in urban density and an ageing population.
The study has shown that daily maximum and minimum temperatures from the Bureau of Meteorology forecasts can be used to calculate temperature thresholds for heat alert days. The key risk factors related to adverse health outcomes were found to be areas with intense urban heat islands, areas with higher proportions of older people, and areas with ethnic communities.
Maps of spatial vulnerability have been developed to provide information to assist emergency managers, healthcare professionals, and ancillary services develop heatwave preparedness plans at a local scale that target vulnerable groups and address heat-related health risks. The numbers of days exceeding current heat thresholds are predicted to increase over the next 20 to 40 years in all Australian capital cities.
Authors: Margaret E. Loughnan, Nigel J. Tapper, Thu Phan, Kellie Lynch, Judith A. McInne
An investigation of incoming short and long wave radiation over Christchurch
No full textVariations in short and long wave radiation were measured across the city of Christchurch over a five month period to mid-winter 1976. Two fixed climate stations were the basis of data collection, with mobile traverse s completing the spatial pattern of urban/ rural variations in radiation.
Analysis of this data showed an average attenuation of incoming short wave radiation for clear days of 14.9 % in the central city, with peaks as high as 30 %. A definite daily and seasonal trend was perceived with greater attenuation at lower solar elevations. These figures appear to be quite high compared with the attenuation reported from other mid-latitude cities. The atmospheric transmissivity for direct beam radiation was found to be dominantly influenced by smoke pollution, but continued attenuation in the summer months suggested the presence of pollutants not measured in this study.
Long wave radiation was also shown to have a definite urban/rural trend, with the urban excess being an average daily 8.5% for clear days which is comparable with the only other such study. The increase in long wave radiation nearly exactly balanced the short wave deficit in urban areas during daytime, but at night the urban area showed a gain in radiant energy from this source over the rural areas. Examination of possible reasons for the urban excess long wave radiation again indicated the importance of smoke pollution in radiation transfer, but the true influence of urban temperatures was thought to have been masked by an urban thermal lag found to coincide with peak incoming long wave radiation during the day.
Application of simple models to predict incoming short and long wave radiation achieved varied success, but also showed the importance of particulates in the transfer of short and long wave radiation. The use of models helped in the development of a hypothesis using the urban pollutant layer to explain the urban/rural divergence in both long and short wave radiation
Geochemical and microbiological fingerprinting of airborne dust that fell in Canberra, Australia, in October 2002
No full textDuring the night of 22-23 October 2002, a large amount of airborne dust fell with rain over Canberra, located some 200 km from Australia's east coast, and at an average altitude of 650 m. It is estimated that during that night about 6 g m-2 of aeolian dust fell. We have conducted a vast number of analyses to "fingerprint" some of the dust and used the following techniques: grain size analysis; scanning electron microscope imagery; major, trace, and rare earth elemental, plus Sr and Nd isotopic analyses; organic compound analyses with respective compound-specific isotope analyses; pollen extraction to identify the vegetation sources; and molecular cloning of 16S rRNA genes in order to identify dust bacterial composition. DNA analyses show that most obtained 16S rRNA sequences belong mainly to three groups: Proteobacteria (25%), Bacteriodetes (23%), and gram-positive bacteria (23%). In addition, we investigated the meteorological conditions that led to the dust mobilization and transport using model and satellite data. Grain sizes of the mineral dust show a bimodal distribution typical of proximal dust, rather than what is found over oceans, and the bimodal aspect of size distribution confirms wet deposition by rain droplets. The inorganic geochemistry points to a source along/near the Darling River in NW New South Wales, a region that is characteristically semiarid, and both the organic chemistry and palynoflora of the dust confirm the location of this source area. Meteorological reconstructions of the event again clearly identify the area near Bourke-Cobar as being the source of the dust. This study paves the way for determining the export of Australian airborne dust both in the oceans and other continents.No Full Tex
Associated results of Phase 1 of the Urban-PLUMBER model evaluation project
No full textArchive of: https://urban-plumber.github.io/AU-Preston/plots/
Files in this folder are associated with the manuscript:
“Evaluation of 30 urban land surface models in the Urban-PLUMBER project: Phase 1 results”
Files are an archive of the website https://urban-plumber.github.io/AU-Preston/plots/ as of 2nd December 2022.
Use of any data must give credit through citation of the above manuscript, the data repository, and other site references as appropriate.
Corresponding author: Mathew Lipson ([email protected])
Usage
Load the "index.html" to navigate through plots and results subpages
Description
These files include results from Phase 1 of the Urban-PLUMBER model evaluation project for urban areas.
Data includes:
- individual model results (error metrics) and submission metadata
- individual model plots (timeseries, subsets, energy closure, distributions)
- collective timeseries for every submitted output in the baseline experiment
- collective timeseries for every submitted output in the detailed experiment
- supplementary material for the manuscript
- variable definitions
Authors
Mathew Lipson, Sue Grimmond, Martin Best, Gab Abramowitz, Andrew Coutts, Nigel Tapper,
Jong-Jin Baik, Meiring Beyers, Lewis Blunn, Souhail Boussetta, Elie Bou-Zeid,
Martin G. De Kauwe, Cécile de Munck, Matthias Demuzere, Simone Fatichi,
Krzysztof Fortuniak, Beom-Soon Han, Maggie Hendry, Yukihiro Kikegawa, Hiroaki Kondo,
Doo-Il Lee, Sang-Hyun Lee, Aude Lemonsu, Tiago Machado, Gabriele Manoli, Alberto Martilli,
Valéry Masson, Joe McNorton, Naika Meili, David Meyer, Kerry A. Nice, Keith W. Oleson,
Seung-Bu Park32, Michael Roth33, Robert Schoetter34, Andres Simon35, Gert-Jan Steeneveld,
Ting Sun, Yuya Takane, Marcus Thatcher, Aristofanis Tsiringakis, Mikhail Varentsov,
Chenghao Wang, Zhi-Hua Wan
A role for alpha4(non-alpha6)* nicotinic acetylcholine receptors in motor behavior
No full textFirst author Lindsey G. Soll r is a doctoral student in the Neuroscience program in the Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.Nicotinic acetylcholine receptors (nAChRs) containing either the alpha4 and/or alpha6 subunit are robustly expressed in dopaminergic nerve terminals in dorsal striatum where they are hypothesized to modulate dopamine (DA) release via acetylcholine (ACh) stimulation from cholinergic interneurons. However, pharmacological blockade of nAChRs or genetic deletion of individual nAChR subunits, including alpha4 and alpha6, in mice, yields little effect on motor behavior. Based on the putative role of nAChRs containing the alpha4 subunit in modulation of DA in dorsal striatum, we hypothesized that mice expressing a single point mutation in the alpha4 nAChR subunit, Leu9'Ala, that renders nAChRs hypersensitive to agonist, would exhibit exaggerated differences in motor behavior compared to WT mice. To gain insight into these differences, we challenged WT and Leu9'Ala mice with the alpha4beta2 nAChR antagonist dihydro-beta-erythroidine (DHbetaE). Interestingly, in Leu9'Ala mice, DHbetaE elicited a robust, reversible motor impairment characterized by hypolocomotion, akinesia, catalepsy, clasping, and tremor; whereas the antagonist had little effect in WT mice at all doses tested. Pre-injection of nicotine (0.1 mg/kg) blocked DHbetaE-induced motor impairment in Leu9'Ala mice confirming that the phenotype was mediated by antagonism of nAChRs. In addition, SKF82958 (1 mg/kg) and amphetamine (5 mg/kg) prevented the motor phenotype. DHbetaE significantly activated more neurons within striatum and substantia nigra pars reticulata in Leu9'Ala mice compared to WT animals, suggesting activation of the indirect motor pathway as the circuit underlying motor dysfunction. ACh evoked DA release from Leu9'Ala striatal synaptosomes revealed agonist hypersensitivity only at alpha4(non-alpha6)* nAChRs. Similarly, alpha6 nAChR subunit deletion in an alpha4 hypersensitive nAChR (Leu9'Ala/alpha6 KO) background had little effect on the DHbetaE-induced phenotype, suggesting an alpha4(non-alpha6)* nAChR-dependent mechanism. Together, these data indicate that alpha4(non-alpha6)* nAChR have an impact on motor output and may be potential molecular targets for treatment of disorders associated with motor impairment.Neuroscienc
Stem and leaf gas exchange and their responses to fire in a north Australian tropical savanna
No full textWe measured stem CO2 efflux and leaf gas exchange in a tropical savanna ecosystem in northern Australia, and assessed the impact of fire on these processes. Gas exchange of mature leaves that flushed after a fire showed only slight differences from that of mature leaves on unburned trees. Expanding leaves typically showed net losses of CO2 to the atmosphere in both burned and unburned trees, even under saturating irradiance. Fire caused stem CO2 efflux to decline in overstory trees, when measured 8 weeks post-fire. This decline was thought to have resulted from reduced availability of C substrate for respiration, due to reduced canopy photosynthesis caused by leaf scorching, and to priority allocation of fixed C towards reconstruction of a new canopy. At the ecosystem scale, we estimated the annual above-ground woody-tissue CO2 efflux to be 275 g C m−2 ground area year−1 in a non-fire year, or approximately 13% of the annual gross primary production.
We contrasted the canopy physiology of two co-dominant overstory tree species, one of which has a smooth bark on its branches capable of photosynthetic re-fixation (Eucalyptus miniata), and the other of which has a thick, rough bark incapable of re-fixation (Eucalyptus tetrodonta). Eucalyptus miniata supported a larger branch sapwood cross-sectional area in the crown per unit subtending leaf area, and had higher leaf stomatal conductance and photosynthesis than E. tetrodonta. Re-fixation by photosynthetic bark reduces the C cost of delivering water to evaporative sites in leaves, because it reduces the net C cost of constructing and maintaining sapwood. We suggest that re-fixation allowed leaves of E. miniata to photosynthesize at higher rates than those of E. tetrodonta, while the two invested similar amounts of C in the maintenance of branch sapwood
Validating digital evidence for legal argument
No full textDigital evidence is now common in legal cases, but the understanding of the legal fraternity as to how far conventional ideas of evidence can be extended into the digital domain lags behind. Evidence determines the truth of an issue but its weight is subject to examination and verification through existing forms of legal argument. There is a need for a practical ‘roadmap’ that can guide the legal practitioner in identifying digital evidence relevant to support a case and in assessing its weight. A vital, but sometimes under estimated stage is that of validating the evidence before evaluating its weight. In this paper we describe a process by which the validation of relevant evidence required for legal argument can be facilitated, by an interrogative approach that ensures the chain of reasoning is sustained
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