651 research outputs found
Integrative Environmental Queries Using Geospatial Web Services
The paper explores the use of geospatial web services for querying and analytical functions on distributed heterogeneous biological databases. A case study and web service implementation was tested on biological collections in Australia. Open geospatial specifications for web services were adequate for the test implementation, although some performance issues on XML-encoded data were identified. More significantly, we highlighted the need for domain specific formats to improve their precision and content to support queries that need to determine value-based identity. We also developed analytical functions well suited to geoprocessing web services that utilised statistical summaries and localised searches versus traditional algorithms that require access to the full dataset
Late Holocene palynology and palaeovegetation of tephra-bearing mires at Papamoa and Waihi Beach, western Bay of Plenty, North Island, New Zealand.
The vegetation history of two mires associated with Holocene dunes near the western Bay of Plenty coast, North Island, New Zealand, is deduced from pollen analysis of two cores. Correlation of airfall tephra layers in the peats, and radiocarbon dates, indicate that the mires at Papamoa and Waihi Beach are c. 4600 and c. 2900 conventional radiocarbon years old, respectively. Tephras used to constrain the chronology of the pollen record include Rotomahana (1886 AD), Kaharoa (700 yr B.P.), Taupo (Unit Y; 1850 yr B.P.), Whakaipo (Unit V; 2700 yr B.P.), Stent (Unit Q; 4000 yr B.P.), Hinemaiaia (Unit K; 4600 yr B.P.), and reworked Whakatane (c. 4800 yr B.P.) at Papamoa, and Kaharoa and Taupo at Waihi Beach. Peat accumulation rates at Papamoa from 4600 - 1850 yr B.P. range from 0.94 to 2.64 mm/yr (mean 1.37 mm/yr). At Waihi Beach, from 2900 yr B.P. - present day, they range from 0.11 to 0.21 mm/yr (mean 0.20 mm/yr). Peat accumulation at both sites was slowest from 1850 to 700 yr B.P., suggesting a drier overall climate during this interval. At both sites, the earliest organic sediments, which are underlain by marine or estuarine sands, yield pollen spectra indicating salt marsh or estuarine environments. Coastal vegetation communities declined at both sites, as sea level gradually fell or the coast prograded, and were eventually superseded by a low moor bog at Papamoa, and a mesotrophic swamp forest at Waihi Beach. These differences, and the marked variation in peat accumulation rates, probably reflect local hydrology and are unlikely to have been climatically controlled. The main regional vegetation during this period was mixed northern conifer-angiosperm forest. Kauri (Agathis australis) formed a minor component of these forests, but populations of this tree have apparently not expanded during the late Holocene at these sites, which are near its present southern limit. Occasional shortlived forest disturbances are detectable in these records, in particular immediately following the deposition of Taupo Tephra. However, evidence for forest clearance during the human era is blurred by the downward dislocation of modern adventi ve pollen at these sites, preventing the clear differentiation of the Polynesian and European eras
Re-identification of c. 15 700 cal yr BP tephra bed at Kaipo Bog, eastern North Island: implications for dispersal of Rotorua and Puketarata tephra beds.
A 10 mm thick, c. 15 700 calendar yr BP (c. 13 100 14C yr BP) rhyolitic tephra bed in the well-studied montane Kaipo Bog sequence of eastern North Island was previously correlated with Maroa-derived Puketarata Tephra. We revise this correlation to Okataina-derived Rotorua Tephra based on new compositional data from biotite phenocrysts and glass. The new correlation limits the known dispersal of Puketarata Tephra (sensu stricto, c. 16 800 cal yr BP) and eliminates requirements to either reassess its age or to invoke dual Puketarata eruptive events. Our data show that Rotorua Tephra comprises two glass-shard types: an early-erupted low-K2O type that was dispersed mostly to the northwest, and a high-K2O type dispersed mostly to the south and southeast, contemporary with late-stage lava extrusion. Late-stage Rotorua eruptives contain biotite that is enriched in FeO compared with biotite from Puketarata pyroclastics. The occurrence of Rotorua Tephra in Kaipo Bog (100 km from the source) substantially extends its known distribution to the southeast. Our analyses demonstrate that unrecognised syn-eruption compositional and dispersal changes can cause errors in fingerprinting tephra deposits. However, the compositional complexity, once recognised, provides additional fingerprinting criteria, and also documents magmatic and dispersal processes
Penetrating component of cosmic radiation in the upper atmosphere
The primary object of this research was to
establish with accuracy the variation of the vertical
intensity of the penetrating component of cosmic radiation as a function of altitude in the neighbourhood of
Edinburgh, geomagnetic latitude 59 °N. By the use of
Geiger- Mueller counters connected in coincidence to form
vertical telescopes, and carried to great heights by
free balloons, it was intended to measure the intensity
of the penetrating radiation from ground level to within
1 per cent of the "top of the atmosphere ".At this time (July 1947) the altitude variation of the total cosmic ray intensity was regarded as
fairly well established. Counter measurements, notably
those of Pfotzer had shown an increase in the total
vertical intensity from ground level to a maximum in the
region of 100 mb. Beyond this point the coincidence
rate decreased rapidly.Similar experiments had been performed with
telescopes containing sufficient lead absorber to exclude
the soft radiation, to determine the altitude variation
of the penetrating component. The results published
prior to 1947, however, disagreed with one another both
qualitatively and quantitatively, and the discrepancies
between tnem could not readily be explained in terms of
either the various geographical locations at which the
measurements were made, or the different geometrical
arrangements used in the counter telescopes. A summary of these results is now given
Macrofossils and pollen representing forests of the pre-Taupo volcanic eruption (c. 1850 yr BP) era at Pureora and Benneydale, central North Island, New Zealand.
Micro- and macrofossil data from the remains of forests overwhelmed and buried at Pureora and Benneydale during the Taupo eruption (c. 1850 conventional radiocarbon yr BP) were compared. Classification of relative abundance data separated the techniques, rather than the locations, because the two primary clusters comprised pollen and litter/wood. This indicates that the pollen:litter/wood within-site comparisons (Pureora and Benneydale are 20 km apart) are not reliable. Plant macrofossils represented mainly local vegetation, while pollen assemblages represented a combination of local and regional vegetation. However, using ranked abundance and presence/absence data, both macrofossils and pollen at Pureora and Benneydale indicated conifer/broadleaved forest, of similar forest type and species composition at each site. This suggests that the forests destroyed by the eruption were typical of mid-altitude west Taupo forests, and that either data set (pollen or macrofossils) would have been adequate for regional forest interpretation.
The representation of c. 1850 yr BP pollen from the known buried forest taxa was generally consistent with trends determined by modern comparisons between pollen and their source vegetation, but with a few exceptions.
A pollen profile from between the Mamaku Tephra (c. 7250 yr BP) and the Taupo Ignimbrite indicated that the Benneydale forest had been markedly different in species dominance compared with the forest that was destroyed during the Taupo eruption. These differences probably reflect changes in drainage, and improvements in climate and/or soil fertility over the middle Holocene
Sedimentation in an artificial lake -Lake Matahina, Bay of Plenty
Lake Matahina, an 8 km long hydroelectric storage reservoir, is a small (2.5 km2), 50 m deep, warm monomictic, gorge-type lake whose internal circulation is controlled by the inflowing Rangitaiki River which drains a greywacke and acid volcanic catchment. Three major proximal to distal subenvironments are defined for the lake on the basis of surficial sediment character and dominant depositional process: (a) fluvial-glassy, quartzofeld-spathic, and lithic gravel-sand mixtures deposited from contact and saltation loads in less than 3 m depth; (b) (pro-)deltaic-quartzofeldspathic and glassy sand-silt mixtures deposited from graded and uniform suspension loads in 3-20 m depth; and (c) basinal-diatomaceous, argillaceous, and glassy silt-clay mixtures deposited from uniform and pelagic suspension loads in 20-50 m depth. The delta face has been prograding into the lake at a rate of 35-40 m/year and vertical accretion rates in pro-delta areas are 15-20 cm/year. Basinal deposits are fed mainly from river plume dispersion involving overflows, interflows, and underflows, and by pelagic settling, and sedimentation rates behind the dam have averaged about 2 cm/year. Occasional fine sand layers in muds of basinal cores attest to density currents or underflows generated during river flooding flowing the length of the lake along a sublacustrine channel marking the position of the now submerged channel of the Rangitaiki River
Incorporating Level Set Methods in Geographical Information Systems (GIS) for Land-Surface Process Modeling
Land-surface processes include a broad class of models that operate at a landscape scale. Currentmodelling approaches tend to be specialised towards one type of process, yet it is the interaction of processesthat is increasing seen as important to obtain a more integrated approach to land management. This paperpresents a technique and a tool that may be applied generically to landscape processes. The technique tracksmoving interfaces across landscapes for processes such as water flow, biochemical diffusion, and plantdispersal. Its theoretical development applies a Lagrangian approach to motion over a Eulerian grid space bytracking quantities across a landscape as an evolving front. An algorithm for this technique, called level setmethod, is implemented in a geographical information system (GIS). It fits with a field data model in GIS andis implemented as operators in map algebra. The paper describes an implementation of the level set methodsin a map algebra programming language, called MapScript, and gives example program scripts forapplications in ecology and hydrology
A Modelling Framework Incorporating a Map Algebra Programming Language
The paper presents a modelling framework to integrate dynamic analysis and spatial analysis, andto apply this to a hydrological application. The dynamic analysis runs a simulation of a set of processmodules. Modules for spatial analysis functionality are implemented in software libraries, or components.Currently we support components for a map algebra language called MapScript, and for spreadsheetcalculations using Excel. An important issue in environmental models and in any modelling framework isdealing with different scale processes. When processes occur over different time or spatial scales but are stillintegrally related, this becomes a problem for applying efficient modelling solutions. The paper reviews twocommon strategies for solving this problem, namely multistep and multigrid methods. Because of theheterogeneous nature of landscapes processes neither is seen as offering a satisfactory solution. We have trieda variant to a multistep solution by allowing the user to specify the timing of different processes that occur ina landscape model. The paper describes the modelling framework and language specification used todescribe module execution. The specification is written in XML to leverage its widespread use in webcomputing environments. The modelling framework may be used for diverse modelling applications inhydrology, landscape assessment, geomorphology and ecology. The paper will demonstrate a mockhydrological application to model runoff in a small watershed
Collaborative Decision-making Processes for Maintaining Biodiversity: Two Australian Case Studies
There have been many models developed by scientists to assist decision-makers in making socio-economic and environmental decisions. It is now recognised that there is a shift in the dominant paradigm to making decisions with stakeholders, rather than making decisions for stakeholders. Our paper investigates two case studies where group model building has been undertaken for maintaining biodiversity in Australia. The first case study focuses on preservation and management of green spaces and biodiversity in metropolitan Melbourne under the umbrella of the Melbourne 2030 planning strategy. A geographical information system is used to collate a number of spatial datasets encompassing a range of cultural and natural assets data layers including: existing open spaces, waterways, threatened fauna and flora, ecological vegetation covers, registered cultural heritage sites, and existing land parcel zoning. Group model building is incorporated into the study through eliciting weightings and ratings of importance for each datasets from urban planners to formulate different urban green system scenarios. The second case study focuses on modelling ecoregions from spatial datasets for the state of Queensland. The modelling combines collaborative expert knowledge and a vast amount of environmental data to build biogeographical classifications of regions. An information elicitation process is used to capture expert knowledge of ecoregions as geographical descriptions, and to transform this into prior probability distributions that characterise regions in terms of environmental variables. This prior information is combined with measured data on the environmental variables within a Bayesian modelling technique to produce the final classified regions. We describe how linked views between descriptive information, mapping and statistical plots are used to decide upon representative regions that satisfy a number of criteria for biodiversity and conservation. This paper discusses the advantages and problems encountered when undertaking group model building. Future research will extend the group model building approach to include interested individuals and community groups
An Integrated Multi-Scaled Decision Support Framework Used in the Formulation and Evaluation of Land-Use Planning Scenarios for the Growth of Hervey Bay
This paper investigates how demographic (socio-economic) and land-use (physical and environmental) data can be integrated within a multi-scaled decision support framework to formulate and evaluate land-use planning scenarios. A case study approach is undertaken using ‘what-if’ planning scenarios for a rapidly growing coastal area in Australia, the Shire of Hervey Bay. The town and surrounding area requires careful planning of future urban growth between competing land-uses. Three potential urban growth scenarios are put forth to address this issue. Scenario A - ‘business as usual’ is based on existing socio-economic trends. Scenario B – ‘maximisation of rates base’ has been derived using optimisation modelling of land valuation data. Scenario C – ‘sustainable development’ has been derived using a number of environmental layers and assigning weightings of importance to each layer using a multiple criteria analysis (MCA) approach. The ‘what-if’ planning scenarios are presented through the use of maps and tables within a geographical information system (GIS), which delineate future possible land-use location-allocations. Work is currently being undertaken to evaluate the effectiveness of each of the three modelling approaches utilised in formulating the different scenarios using both comparative analysis and a goals achievement matrix (GAM), based upon a number of criteria which are derived from key policy objectives outlined in; the regional growth management framework for the Wide Bay Region, and the Hervey Bay City Planning Scheme. The outcomes of this paper discuss the advantages and disadvantages of each of the three modelling approaches with respect to formulating future urban growth scenarios
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