Journal articles on the topic 'Rain and rainfall Northern Territory Darwin'

The wet–dry tropics of northern Australia are characterised by extreme seasonal variation in rainfall and atmospheric vapour pressure deficit, although temperatures are relatively constant throughout the year.This seasonal variation is associated with marked changes in tree canopy cover, although the exact determinants of these changes are complex. This paper reports variation in microclimate (temperature, vapour pressure deficit (VPD)), rainfall, soil moisture, understorey light environment (total daily irradiance), and pre-dawn leaf water potential of eight dominant tree species in an area of savanna near Darwin, Northern Territory, Australia. Patterns of canopy cover are strongly influenced by both soil moisture and VPD. Increases in canopy cover coincide with decreases in VPD, and occur prior to increases in soil moisture that occur with the onset of wet season rains. Decreases in canopy cover coincide with decreases in soil moisture following the cessation of wet season rains and associated increases in VPD. Patterns of pre-dawn water potential vary significantly between species and between leaf phenological guilds. Pre-dawn water potential increases with decreasing VPD towards the end of the dry season prior to any increases in soil moisture. Decline in pre-dawn water potential coincides with both decreasing soil moisture and increasing VPD at the end of the dry season. This study emphasises the importance of the annual transition between the dry season and the wet season, a period of 1–2 months of relatively low VPD but little or no effective rainfall, preceded by a 4–6 month dry season of no rainfall and high VPD. This period is accompanied by markedly increased canopy cover, and significant increases in pre-dawn water potential, which are demonstrably independent of rainfall. This finding emphasises the importance of VPD as a determinant of physiological and phenological processes in Australian savannas.

During wet and dry seasons and transitions of the monsoonal cycle, rates of water turnover and nutritional variables were measured on a population of Rattus colletti which fluctuated between extremes of high and low abundance. Rate of water turnover (RWT in millilitres per day) and body weight ( W, in kilograms) were related allometrically: RWT = aW*O.742 � 0.061, where a varied between seasons and sexes. Seasonal rates of water turnover were consistent with physiological adaptation in R. colletti to seasonal aridity. Rate of water turnover correlated with seasonal hydric regime, varying by a factor of 3.5 between dry and wet seasons. During the wet season, low body weight and lack of breeding seemed to be caused by flooding and its physical and social consequences. During dry season aridity the rats were short of food and water, but not in a dry season when rain fell and breeding ensued. Reproduction increased requirements for food and water in both sexes. Juveniles had relatively high requirements, and shortages appeared to retard growth. Very large populations resulted from prolific breeding after dry season rain had sustained high consumption of food and water on the riverine plains, the dry season habitat. Population decline resulted from very high wet season rainfall followed by a rainless dry season when food and water intakes were depressed, probably because the previous rainfall pattern reduced the availability of sedge corms, the dry season source of food and water. This climatic pattern recurred in the next wet and dry seasons, reinforcing the effects on R, colletti, which became rare for several years on both riverine systems studied.

Within Australia the northern short-nosed bandicoot, Isoodon macrourus, occurs in coastal areas from the Kimberleys to the monsoonal tropics of the Northern Territory and from Cape York Peninsula to the Hawkesbury River, New South Wales (Gordon 1983). The reproductive ecology of I. macrourus has been studied in two captive (Hall 1983; Gemmell 1988) and five natural populations (Gordon 1971, 1974; Gemmell 1982; Hall 1983; Friend 1990; Kem- per et al. 1990; Budiawan 1993). Three of the latter (Darwin, the Mitchell Plateau and Townsville) were in the tropics; breeding at these sites occurred dur- ing the wetter months of the year but not during the summer of 1982/3 in Darwin when the monsoon failed (Friend 1990) or during the relatively dry winter/spring of 1991 in Townsville (Budiawan 1993), suggesting a dependence on rainfall (Friend 1990; Budiawan 1993). We report on differences in the reproduction, growth and development of I. macrourus in Rockhampton, Queensland, from March - October 1993 at four adjacent sites which received different amounts of artificial watering.

The present study analyzes the impacts of global warming of 1.5ºC, 2ºC, and 4ºC above pre-industrial levels in the Brazilian territory. Climate change projected among the different global warming levels has been analyzed for rainfall, temperature and extreme climate indices. The projections are derived from the global climate model HadGEM3-A, from the High-End cLimate Impacts and eXtremes (HELIX) international project, from the United Kingdom, forced by sea surface temperature and sea ice concentration of a subset of six CMIP5 (Coupled Model Intercomparison Project phase 5) global climate models and considering the RCP 8.5 (Representative Concentration Pathways) emissions scenario throughout the 21st century. Projections indicate robust differences in regional climate characteristics. These differences include changes: in the minimum and maximum air temperature close to the surface to all the country’s regions, in extremes of heat, particularly in northern Brazil, in the occurrence of heavy rainfall (Southern and Southeastern regions), and in the probability of droughts and rain deficits in some regions (Northern and Northeastern Brazil).

The present study analyzes the impacts of global warming of 1.5ºC, 2ºC, and 4ºC above pre-industrial levels in the Brazilian territory. Climate change projected among the different global warming levels has been analyzed for rainfall, temperature and extreme climate indices. The projections are derived from the global climate model HadGEM3-A, from the High-End cLimate Impacts and eXtremes (HELIX) international project, from the United Kingdom, forced by sea surface temperature and sea ice concentration of a subset of six CMIP5 (Coupled Model Intercomparison Project phase 5) global climate models and considering the RCP 8.5 (Representative Concentration Pathways) emissions scenario throughout the 21st century. Projections indicate robust differences in regional climate characteristics. These differences include changes: in the minimum and maximum air temperature close to the surface to all the country’s regions, in extremes of heat, particularly in northern Brazil, in the occurrence of heavy rainfall (Southern and Southeastern regions), and in the probability of droughts and rain deficits in some regions (Northern and Northeastern Brazil).

A grid of 447 cells (each 50x50 m) was set up in a wet monsoon rain forest on a gradual slope above the Adelaide River floodplain in the Australian Northern Territory. Surveys of pig (Sus scrofa) rooting were carried out at approximately 3-month intervals from November 1988 to September 1989. The pigs had only limited effects on the forest in both the wet and dry seasons. The seasonally flooded swamp communities (Melaleuca forest and sedgeland) were primarily exploited in the dry season; dryland communities ([Eucalyptus] and Lophostemon forests) were exploited during the wet season. Rainfall during the previous wet season may have influenced the pattern of rooting in the dryland forests. Rooting and ground cover were weakly positively related in 3 out of the 4 surveys.

This paper describes the biogeography at the species level of ants from the Tiwi Islands, and represents the first such analysis for any region in Australia. The Tiwi Islands are located 20 km off the mainland coast near Darwin in northern Northern Territory, and include Australia's second largest insular landmass after Tasmania. The islands receive the highest mean annual rainfall (up to 2000 mm) in monsoonal northern Australia, and they are the closest part of the Australian landmass to south-east Asia. On the basis of ~1300 species records, we list 154 species (including nine introduced) from 34 genera. The richest genera are Polyrhachis (20 species), Monomorium (15), Camponotus (14), Pheidole (12), and Iridomyrmex (11). In all, 66% of the native Tiwi species belong to Torresian (tropical) species groups, which is considerably higher than the 44% for Australia's monsoonal ant fauna as a whole. Fifteen Tiwi ant species are not known from mainland Australia. These include a species of Anonychomyrma, which is the only record of the genus in monsoonal Australia, Polyrhachis debilis, the only representative of the sub-genus Cyrtomyrma known from north-western Australia, and the only species of the araneoides group of Rhytidoponera known from the Northern Territory. Unfortunately, the Tiwi ant fauna also includes the exotic invasive species Pheidole megacephala, which represents a serious conservation threat.

Daily and monthly rainfall data provided by surface rain gauges in the Amazon Basin are sparse and defective, making it difficult to monitor rainfall patterns for certain portions of its territory, in this sense, estimations of precipitation from remote sensing calibrated with rain gauge data are key to overcome this problem. This paper presents a spatiotemporal analysis of the precipitation distribution for Rondônia State, in southwestern Amazonia. Data from Climate Hazards Group InfraRed Precipitation and Station (CHIRPS) were analyzed, using a pooled time analysis of a forty-year period (1981–2020). Data obtained from remote sensing were validated by rain gauges distributed over the study region. Pixel-by-pixel trend analyzes were developed by applying the Mann-Kendall test and Sen’s slope test to study the magnitude of the trend. The analysis revealed that CHIRPS presents a tendency to underestimate precipitation values in most cases. Among the metrics, mean values between very good (<±15%) and good (±15–±35%) were observed using PBIAS; mean RMSE values range from 57.8 mm to 107.9 mm; an average agreement level of 0.9 and an average SES of 0.5; and good fit for the linear regression model (average R2 > 0.70) for about 64.7% of the stations. Sen’ slope spatialization results show a reduction of approximately −15 mm year−1, with decrease mainly in the Northern Region of Rondônia, which has extensive areas where the native forest has been replaced by pasture.

Abstract Variability in the wet season of tropical northern Australia is examined over its main months, November–March, with a focus on zonal differences between the western, central, and eastern domains, which encompass the northern parts of Western Australia, Northern Territory, and Queensland, respectively. The seasonal progression of the wet season is similar across the region, with steadily increasing atmospheric moisture and rainfall into the core months of the monsoon, January and February, decreasing into March. This seasonal progression differs in the eastern domain, where there is an extension of premonsoonal conditions into December, and a delay of the onset of the monsoon until January. An analysis of TRMM precipitation features (PFs) reveals more intense convection during the premonsoon, steadily decreasing in intensity to much shallower convection by March, with a steady increase in the overall number of PFs throughout the wet season. Regionally, the intensity of PFs steadily decreases eastward across northern Australia with significantly weaker, shallower PFs over the eastern domain. Intraseasonal variability associated with the Madden–Julian oscillation (MJO) has a consistent impact on the rainfall and the total number of TRMM PFs across northern Australia, with both increasing and decreasing during the active and suppressed phases, respectively. However, regional variations in the effect of the MJO lead to radically different characteristics of PFs during the suppressed phases; intense convection and thunderstorms become more frequent over the western and central domains, while shallow PFs associated with the warm rain precipitation process increase in number over the eastern domain.

A series of vegetation sites was established in Australia's Northern Territory between Darwin and Tennant Creek, a distance of approximately 1000 km and 7° latitude (12°30'–19°30'S). This region encompasses a strong environmental gradient in mean annual moisture availability (450–1600 mm) whilst remaining within a predominantly summer monsoonal rainfall regime. All sites are within eucalypt-savanna habitats on lighter textured soils (sands–loams). Major changes in family and species representation occur at approximately 16–17° latitude, supporting findings of other workers. Within these eucalypt-savanna communities, the percentage of annual species is consistently around 30% regardless of latitude. However, the distribution of resource allocation strategies used by perennial plants exhibits distinct latitudinal trends. The proportion of deciduous and seasonally perennial species declines with latitude whilst suffrutescent shrub species become increasingly abundant. Species possessing root structures adapted for storage purposes appear to be limited to latitudes north of 15°S.

Monsoon rainforest in the Northern Territory exists as an archipelago of tiny patches thought to be previously more continuous but having had retracted to a fragmented state by the Pleistocene. However, there is evidence of some more recent rainforest expansion, and many species have seeds that are dipsersed by small frugivores (birds and bats). Carpentaria acuminata and Ptychosperma bleeseri are endemic to the Northern Territory and Syzygium nervosum is endemic to the Northern Territory within its Australian distribution. Carpentaria acuminata and S. nervosum are common through moist rainforest, but P. bleeseri is rare, found in eight locations near Darwin. All have frugivore-dispersed seeds. The three species were surveyed across their geographic range to compare their population genetics. The results from C. acuminata and S. nervosum were analysed to investigate the distribution of allelic diversity, the effect of patch size and isolation on genetic diversity, and the effectiveness of seed dispersal by vagile frugivores. Genetic diversity (expected heterozygosity) was correlated with mean annual rainfall in both S. nervosum and C. acuminata. Genetic diversity (alleles per locus, percentage of polymorphic loci, expected heterozygosity) was also negatively correlated with population isolation but not patch size in C. acuminata. There was significant heterogeneity and low gene flow among C. acuminata populations (FST 0.379, Nm = 0.39) but not among S. nervosum populations, which had substantial evidence of gene flow (FST 0.118, Nm = 1.67). The distribution of rare alleles in C. acuminata was consistent with the theory of Pleistocene retraction to refugia. Ptychosperma bleeseri was genetically uniform across all sites. Only four individuals differed in their genotypes. The results suggest that the present populations originated from a single founder population rather than having independently contracted from a more extensive distribution. All three species had evidence of some more recent population expansion.

Abstract. Northern Italy is frequently affected by severe precipitation conditions often inducing flood events with associated loss of properties, damages and casualties. The capability of correctly forecast these events, strongly required for an efficient support to civil protection actions, is still nowadays a challenge. This difficulty is also related with the complex structure of the precipitation field in the Alpine area and, more generally, over the Italian territory. Recently a new generation of non-hydrostatic meteorological models, suitable to be used at very high spatial resolution, has been developed. In this paper the performance of the non-hydrostatic Lokal Modell developed by the COSMO Consortium, is analysed with regard to a couple of intense precipitation events occurred in the Piemonte region in Northern Italy. These events were selected among the reference cases of the Hydroptimet/INTERREG IIIB project. LM run at the operational resolution of 7km provides a good forecast of the general rain structure, with an unsatisfactory representation of the precipitation distribution across the mountain ranges. It is shown that the inclusion of the new prognostic equations for cloud ice, rain and snow produces a remarkable improvement, reducing the precipitation in the upwind side and extending the intense rainfall area to the downwind side. The unrealistic maxima are decreased towards observed values. The use of very high horizontal resolution (2.8 km) improves the general shape of the precipitation field in the flat area of the Piemonte region but, keeping active the moist convection scheme, sparse and more intense rainfall peaks are produced. When convective precipitation is not parametrised but explicitly represented by the model, this negative effect is removed.

Four supplementation treatments to investigate wet seasons responses were imposed on eight Brahman/Shorthom cross herds totalling 870 animals of all classes (cows and calves, bulls, heifers and steers). They grazed 12,300 ha of native pasture in the Darwin district of the Northern Territory. The treatments were: (i) control (no wet season supplement), (ii) Mineral (Ultraphos - supplementation with 13 minerals during the wet season), (iii) +Protein (Ultrapro-50 - the same 13 minerals plus non-protein nitrogen (WN) and true protein over the wet season), and (iv) Strategic (strategic use of salt, mineral and hTN supplements over the early wet, mid wet and late wet seasons respectively). All treatments received an hTN plus mineral supplement (Uramol) during the dry season. Supplement intakes by the herds were measured monthly for three years. Intake of Salt, Ultraphos and Ultrapro-50 supplements averaged 43, 124 and 149 g/animal/day respectively during the three wet seasons. Losses of the molasses-based block formulations due to rain were small (7%) during the wet season. However, up to one third of each pure salt block was eroded. Intake of Uramol during the three dry seasons averaged 182 g/animal/day across all herds. No urea toxicity problems were noticed over the three years of the supplement programme, despite high intakes during the dry season. All animals consumed some supplement. However, levels of supplement intake: (i) increased with the seasonal decrease in native pasture quality, (ii) decreased with an increase in proportion of paddock burnt, (iii) varied between animal classes, with lactating cows consuming 64% more supplement than non-lactating cows in two of the three years, and (iv) varied between individuals within classes. Individual intake varied widely (from 10 to 835 glanirnallday for lactating cows) with no significant correlation between individual intake and the pregnancy rate or average daily liveweight gain.

Embedded in the extensive Eucalyptus open forests and savanna woodlands that dominate the northern Australian landscape are patches of monsoon rain forest and Acacia thickets and woodlands. In this paper, the vertebrate species composition of patches of lancewood (Acacia shirleyi) thickets and woodlands of the Northern Territory was compared with that of other environments of this region: pindan woodlands (A. eriopoda and A. tumida), gidgee woodlands (A. georginae), patches of monsoon rain forests and the extensive Eucalyptus open forests and woodlands. The vertebrate fauna of lancewood thickets is distinct for that of Eucalyptus open forests, and has fewer species. Differences in species composition and richness are associated with substantial differences in resource availability, with lancewood thickets having far less grass cover (and hence relatively few granivorous birds and rodents, but more ground-feeding insectivorous and omnivorous birds), fewer nectar-bearing flowers (and hence fewer nectarivorous birds) and lower structural and floristic diversity than Eucalyptus forests. There was little difference in species richness or total abundance between the three types of Acacia woodlands sampled. Lancewood thickets had fewer species than monsoon rain forests to coastal dry monsoon rain forests to inland dry monsoon rain forests to lancewood thickets to pindan woodlands to gidgee woodlands, in accord with the pronounced rainfall gradient of this region and with canopy cover and height. Within this broad continuum the three Acacia woodlands were most closely grouped. Species turnover along this gradient consisted of substantial decrease or loss of some foraging groups (e.g. frugivorous birds) or replacement of species within broad foraging groups. The faunal relationship of the monsoon rain forests and Acacia communities provides some support for considering these fire-sensitive environments as fragments of a formerly extensive continuum. Three species (Pomatostomus temporalis, Struthidea cinerea and Melanodryas cucullata), all ground-foraging insectivorous or omnivorous birds, were significantly associated with lancewood in this region, but all three have extensive ranges beyond this area.

Abstract. The Apuan Alps region is one of the rainiest areas in Italy (more than 3000 mm/year), in which frequently heavy and concentrated rainfall occurs. This is particularly due to its geographical position and conformation: the Apuan chain is located along the northern Tuscan coast, close to the Ligurian Sea, and the main peaks reach almost 2000 m. In several cases, the storms that hit the area have triggered many shallow landslides (soil slip-debris flows), which exposed the population to serious risks (during the 19 June 1996 rainstorm about 1000 landslides were triggered and 14 people died). The assessment of the rainfall thresholds is very important in order to prepare efficient alarm systems in a region particularly dedicated to tourism and marble activities. With the aim of contributing to the landslide hazard evaluation of the southern Apuan Alps territory (upper Versilia area), a detailed analysis of the main pluviometric events was carried out. The data recorded at the main rain gauge of the area from 1975 to 2002 were analysed and compared with the occurrence of soil slips, in order to examine the relationship between soil slip initiation and rainfall. The most important rainstorms which triggered shallow landslides occurred in 1984, 1992, 1994, 1996, 1998 and 2000. Many attempts were made to obtain a possible correlation between rainfall parameters and the occurrence of soil slip phenomena and to identify the local rainfall threshold for triggering shallow landslides. A threshold for soil slip activity in terms of mean intensity, duration and mean annual precipitation (MAP) was defined for the study area. The thresholds obtained for the southern Apuan Alps were also compared with those proposed by other authors for several regions in the world. This emphasized the high value of the rain threshold for shallow landslide activity in the Apuan area. The high threshold is probably also linked to the high mean annual precipitation and to the high frequency of rainstorms.

The fall of phyllodes from Acacia aneura F.Muell. ex Benth. (mulga) in central Australia was studied over 22 months from mid-1958 at four locations within a livestock reserve north of Alice Springs in the Northern Territory, in order to identify rainfall or seasonal triggers. Phyllode fall increased by at least an order of magnitude for short periods following rain of 15–20mm or more on a ‘mature’ mulga site and similar trends were apparent for ‘young’ and ‘desert form’ mulga on the same site, and on a second, independent, ‘mature’ site. When rates of phyllode fall were high after substantial rain, at both ‘mature’ locations, ~30% of nitrogen and ~50% of phosphorus were withdrawn before abscission, suggesting that mulga was markedly conservative of these nutrients. Conversely, under dry conditions, when phyllode fall was relatively low (&lt;200mgm−2day−1), concentrations of nitrogen and phosphorus in fallen phyllodes were higher. Concentrations of potassium, calcium, magnesium and sodium did not vary consistently with increasing rate of phyllode fall, although overall levels of calcium and potassium were considerably higher in the second ‘mature’ location. This legacy study is of renewed interest given the potential of mulga communities to contribute to national carbon stocks, and the consequent need for robust field-based data on growth dynamics and carbon fluxes.

The paper presents the results of research of heavy and extreme precipitation in the form of rain (> 50 mm / 12 h) and snow (> 20 mm / 12 h) using the data from the atmospheric reanalysis ERA5 for the period of 1979-2019. According to the data of the European Centre for Medium-Range Weather Forecasts obtained through the numerical modeling and resulting from the data assimilation at the nodes of a regular grid with a spatial resolution of 0,25°×0,25°, there are 131 and 136 days with rain and snow during which precipitation intensity reached the criteria of meteorological phenomena of the 2nd and 3rd levels of danger. It was discovered that the last 40 years in Ukraine proved to have a tendency of an increased number of cases of heavy snowfall, and a slightly decreased number of heavy rains. The research pays considerable attention to the spatial-temporal analysis of the frequency and intensity of heavy rainfall with consideration of geographical factors. It determines the seasonal course of heavy and extreme precipitation, the maximum and minimum values of which did not differ from the climatic standard values observed during meteorological observations. Rainfalls with precipitation rates of more than 50 mm over 12 hours were observed almost over the entire territory of Ukraine and the maximum frequency zones were detected over the Carpathian Mountains, Donetsk Ridge, Podolsk Upland, and the south-western part of the country. Heavy snowfalls with more than 20 mm precipitation over 12 hours mostly occurred in the Carpathian region. The analysis of the geographical distribution revealed a center with maximum values of rain intensity (120-133 mm over 12 h) off the coast of the Sea of Azov, and the heaviest snowfalls (34-38 mm over 12 h) mainly formed in the Carpathian region. The paper established the types of elementary circulation mechanisms of Dzerdzeevsky’s synoptic classification of Northern Hemisphere atmospheric circulation. These types, when continuous in nature, resulted in a significantly increased precipitation in the form of rain and snow. According to the reanalysis data, cases with the maximum rain intensity were found over the period of 23 to 27 July 2008 when a catastrophic flood was observed in the Ukrainian Carpathians. This fact indicates that the structure of the field of heavy precipitation over the territory of Ukraine was adequately reproduced by the respective model of the European Centre for Medium-Range Weather Forecasts.

The ley farming systems proposed for the Australian semi-arid tropics involve rotating an annual pasture (usually legume) with crops sown using no-tillage. These systems were developed to overcome many of the climatic constraints that beset previous attempts at cropping in the region. However, difficulties in the timing of farm operations also contributed to past failures. No analysis of the operational aspects of ley farming had been made; this was the objective of this paper. During the transition between wet and dry seasons rainfall is extremely variable. These periods were shown to be the most critical time for operations in ley farming systems. During the dry-wet transition, management of ley pastures is very difficult because pastures must provide grazing for livestock as well as sufficient soil cover for timely sowing of a following crop. Legume pastures have reduced grazing value at this time due to spoilage by early rain. Similarly, during the wet-dry transition annual pastures must be allowed to set seed at a time when crops are yet to be harvested and stubbles are not available for grazing. It was suggested that including separate paddocks of perennial pasture could reduce the demand on annual pastures during the seasonal transitions. A limited number of days to sow a crop combined with severe yield penalties for late sowing restrict the area that can be sown in any season. Sowing opportunities were determined for 3 locations in the Northern Territory. No-tillage was shown to increase the potential number of sowing days. However, the time available to apply glyphosate before sowing using no-tillage was confined to the morning due to risk of afternoon rainshowers reducing efficacy. The number of seasons where a particular crop or cultivar could not be sown was independent of the method of tillage. The wet-dry transition was shown to be important for harvest operations. Our analysis of 3 sites in the Northern Territory suggests that for mungbean and sorghum, later maturity combined with prompt harvest will reduce the risk of poor seed quality due to weathering and could permit earlier sowing. However, for sorghum, an economic assessment of these practices required research that can quantify the interaction between sowing date, time-to-maturity and grain yield.

Abstract A forecast product focusing on the onset of the north Australian wet season using a dynamical ocean–atmosphere model is developed and verified. Onset is defined to occur when a threshold rainfall accumulation of 50 mm is reached from 1 September. This amount has been shown to be useful for agricultural applications, as it is about what is required to generate new plant growth after the usually dry period of June–August. The normal (median) onset date occurs first around Darwin in the north and Cairns in the east in late October, and is progressively later for locations farther inland away from these locations. However, there is significant interannual variability in the onset, and skillful predictions of this can be valuable. The potential of the Predictive Ocean–Atmosphere Model for Australia (POAMA), version 2, for making probabilistic predictions of onset, derived from its multimember ensemble, is shown. Using 50 yr of hindcasts, POAMA is found to skillfully predict the variability of onset, despite a generally dry bias, with the “percent correct” exceeding 70% over about a third of the Northern Territory. In comparison to a previously developed statistical method based solely on El Niño–Southern Oscillation, the POAMA system shows improved skill scores, suggesting that it gains from additional sources of predictability. However, the POAMA hindcasts do not reproduce the observed long-term trend in onset dates over inland regions to an earlier date despite being initialized with the observed warming ocean temperatures. Understanding and modeling this trend should lead to further enhancements in skill.

Farmers often experience inconsistent responses when using herbicides to terminate an established lucerne pasture prior to cropping. In an attempt to redress this problem, a series of field experiments were conducted between 1999 and 2002 at various locations in southern and northern New South Wales, the Australian Capital Territory, and south Western Australia that aimed to identify management guidelines that improved the efficacy of herbicide mixtures commonly used to remove lucerne. Collectively, these studies indicated that herbicides were generally less effective when applied either early (less than 2 weeks) or late (6 weeks or more) in the regrowth cycle of lucerne after defoliation. Herbicide efficacy tended to be greatest if applied to regrowth 3–5 weeks after defoliation, which corresponds to a time when the lucerne crown and root reserves are likely to be in the process of being replenished by photoassimilates transported from the shoot. The impact of timing of herbicide application in relation to season was compared at a number of locations. Across all the sites and years, spring herbicide applications were generally the most effective, removing on average 87% of the lucerne (range 53–100%) compared with 72% in summer (24–100%) and 60% in autumn (7–92%). Spring applications were also more consistent in their effect, removing >80% of the lucerne plants in 9 out of 12 experiments, whereas similar rates of removal occurred on 4 occasions in 9 summer applications and only twice in 8 autumn applications. Some of the seasonal variation could be explained by differences in the amount of rainfall prior to herbicide applications. It was assumed that the relationship between rainfall and herbicide efficacy reflected the stimulation of lucerne shoot and root growth by the additional soil moisture before herbicide treatment. Herbicide mixtures that contained ingredients such as picloram that retain residual activity in the soil tended to be more effective and were less influenced by lucerne growth and season than those herbicides with little or no residual activity. However, such chemicals could potentially restrict which crops can subsequently be grown after a lucerne pasture has been removed. It was concluded that >80% of lucerne plants were likely to be removed using herbicides provided that the herbicide treatment was applied to actively growing lucerne 3–5 weeks after defoliation, and when greater than 70–95 mm rain had fallen in the 6–8 weeks prior to application.

This paper presents a comparative study in predicting the monthly average solar radiation for Darwin, Australia (latitude 12.46 deg S longitude 130.84 deg E). The city of Darwin, Northern Territory (NT), has the highest and most consistent sunshine duration among all the other Australian states. This unique climate presents an opportunity for photovoltaic (PV) applications. Reliable and accurate predictions of solar radiation enable potential site locations, which exhibit high solar radiations and sunshine hours, to be identified for PV installation. Three predictive models were investigated in this study—the linear regression (LR), Angstrom–Prescott–Page (APP), and the artificial neural network (ANN) models. The mean global solar radiation coupled with the climate data (mean minimum and maximum temperatures, mean rainfall, mean evaporation, and sunshine fraction) obtained from the Australian Bureau of Meteorology (BoM) formed the basis of the dataset. Using simple and easily obtainable climate data presents an added advantage by reducing model complexity. Predictive results showed the root mean square errors (RMSEs) obtained were 6.72%, 13.29%, and 8.11% for the LR, APP, and ANN models, respectively. The predicted solar exposure from the LR model was then compared with the satellite-derived data to assess the accuracy of the LR method.

IntroductionTraditionally, suburbs have been conceived as dormitory – in binary opposition to the inner-city (Powell). Supporting this stereotypical view have been gendered binaries between inner and outer city areas; densely populated vs. sprawl; gentrified terraces and apartment culture vs. new estates and first home buyers; zones of (male) production and creativity against (female) sedate, consumer territory. These binaries have for over a decade been thoroughly criticised by urban researchers, who have traced such representations and demonstrated how they are discriminatory and incorrect (see Powell; Mee; Dowling and Mee). And yet, such binaries persist in popular media commentaries and even in academic research (Gibson and Brennan-Horley). In creative city research, inner-city areas have been bestowed with the supposed correct mix of conditions that may lead to successful creative ventures. In part, this discursive positioning has been borne out of prior attempts to mapthe location of creativity in the city. Existing research on the geography of creativity in the city have relied on proxy data forms: mapping data on firms and/or employment in the creative industry sectors (e.g. Gibson, Murphy and Freestone; Markusen et al.; Watson). In doing so, the focus has rested on “winners” – i.e. headquarters of major arts and cultural institutions located in inner city/CBD locations, or by looking for concentrations of registered creative businesses. Such previous studies are useful because they give some indication of the geographical spread and significance of creative activities in cities, and help answer questions about the locational preferences of creative industries, including their gravitational pull towards each other in an agglomerative sense (Scott). However, such studies rely on (usually) one proxy data source to reveal the presence of creative activities, rather than detail how creativity is itself apparent in everyday working lives, or embedded in the spaces, networks and activities of the city. The latter, more qualitative aspects of the lived experience of creativity can only at best be inferred from proxy data such as employment numbers and firm location. In contrast, other researchers have promoted ethnographic methods (Drake; Shorthose; Felton, Collis and Graham) including interviewing, snowballing through contacts and participant observation, as means to get ‘inside’ creative industries and to better understand their embeddedness in place and networks of social relations. Such methods provide rich explanation of the internal dynamics and social logics of creative production, but having stemmed from text-based recorded interviews, they produce data without geographical co-ordinates necessary to be mapped in the manner of employment or business location data – and thus remain comparatively “aspatial”, with no georeferenced component. Furthermore, in such studies relational interactions with material spaces of home, work and city are at best conveyed in text form only – from recorded interviews – and thus cannot be aggregated easily as a mapped representation of city life. This analysis takes a different tack, by mapping responses from interviews, which were then analysed using methods more common in mapping and analysing proxy data sources. By taking a qualitative route toward data collection, this paper illustrates how suburbs can actually play a major role in creative city economies, expanding understandings of what constitutes a creative workplace and examining the resulting spatial distributions according to their function. Darwin and the Creative Tropical City Project This article draws on fieldwork carried out in Darwin, NT a small but important city in Australia’s tropical north. It is the government and administration capital of the sparsely populated Northern Territory and continues to grapple with its colonial past, a challenging climate, small population base and remoteness from southern centres. The city’s development pattern is relatively new, even in Australian terms, only dating back to the late 1970s. After wholesale destruction by Cyclone Tracy, Darwin was rebuilt displaying the hallmarks of post-1970 planning schemes: wide ring-roads and cul-de-sacs define its layout, its urban form dominated by stout single-story suburban dwellings built to withstand cyclonic activity. More recently, Darwin has experienced growth in residential tower block apartments, catering to the city’s high degree of fly-in, fly-out labour market of mining, military and public service workers. These high rise developments have been focussed unsurprisingly on coastal suburbs with ample sections of foreshore. Further adding to its peculiar layout, the geographic centre is occupied by Darwin Airport (a chief military base for Australia’s northern frontier) splitting the northern suburbs from those closer to its small CBD, itself jutting to the south on a peninsula. Lacking then in Darwin are those attributes so often heralded as the harbingers of a city’s creative success – density, walkability, tracts of ex-industrial brownfields sites ripe for reinvention as creative precincts. Darwin is a city dominated by its harsh tropical climate, decentralised and overtly dependant on private car transport. But, if one cares to look beyond the surface, Darwin is also a city punching above its weight on account of the unique possibilities enabled by transnational Asian proximity and its unique role as an outlet for indigenous creative work from across the top of the continent (Luckman, Gibson and Lea). Against this backdrop, Creative Tropical City: Mapping Darwin’s Creative Industries (CTC), a federally funded ARC project from 2006 to 2009, was envisaged to provide the evidential base needed to posit future directions for Darwin’s creative industries. City and Territory leaders had by 2004 become enchanted by the idea of ‘the creative city’ (Landry) – but it is questionable how well these policy discourses travel when applied to disparate examples such as Darwin (Luckman, Gibson and Lea). To provide an empirical grounding to creative city ideas and to ensure against policy fetishism the project was developed to map the nature, extent and change over time of Darwin’s creative industries and imagine alternate futures for the city based on a critical appraisal of the applicability of national and international creative industry policy frameworks to this remote, tropical location (Lea et al.). Toward a Typology of Darwin’s Creative Workplaces This article takes one data set gathered during the course of the CTC project, based around a participatory mapping exercise, where interviewees responded to questions about where creative industry activities took place in Darwin by drawing on paper maps. Known as mental maps, these were used to gather individual representations of place (Tuan), but in order to extend their applicability for spatial querying, responses were transferred to a Geographic Information System (GIS) for storage, collation and analysis (Matei et al.). During semi-structured interviews with 98 Darwin-based creative industry practitioners, participants were provided with a base map of Darwin displaying Statistical Local Area (SLA) boundaries and roads for mark up in response to specific questions about where creative activities occurred (for more in depth discussion of this method and its varied outputs, refer to Brennan-Horley and Gibson). The analysis discussed here only examines answers to one question: “Where do you work?” This question elicited a total of 473 work locations from 98 respondents – a fourfold increase over statistics gleaned from employment measures alone (Brennan-Horley). Such an increase resulted from participants identifying their everyday work practices which, by necessity, took place across multiple locations. When transferring the spatial location of workplaces into the GIS, each site was coded depending on whether it was cited by the interviewee as their “major” or primary place of work, or if the place being discussed played a secondary or “minor” role in their creative practice. For example, an artist’s studio was categorised as major, but other minor sites also featured in their mental maps, for example, galleries, supply locations and teaching sites. Each worksite was then assigned to one of four categories: Front, Back, Networking and Supply (Table 1). In a similar fashion to McCannell’s work on the “front and back regions” of tourist towns (597), the creative industries, predicated on the production and exchange of texts, objects and ideas also display front spaces of sorts – sites that facilitate interactions between practitioner and audiences, spaces for performance and consumption. Operating behind these front spaces, are sites where creative endeavours take place – perhaps not as so readily seen or engaged with by wider publics. For example, a rehearsal room, artist’s studio or a theatre company’s office may not be key sites of interaction between creator and audience but remain nonetheless important sites of creative work. However, a binary of Front versus Back could not encapsulate the variety of other everyday, prosaic work sites evident in the data. Participants indicated on their maps visits to the post office to send artworks, going to Bunnings to buy paint (and inadvertently networking with others), through to more fleeting spaces such as artist materials fossicked from parklands to photoshoot locations. These supply sites (each themselves positioned along a continuum of “creative” to “mundane”) were typified as supply locations: sites that act as places to gather inputs into the creative process. Finally, sites where meetings and networking took place (more often than not, these were indicated by participants as occurring away from their major work place) were assigned under a heading of networking spaces. Table 1: A typology of creative workplaces Space Definition Coded examples Front A space for consumption/exchange of creative goods, outputs or expertise. Performance space, Market, Gallery, Client Location, Shopfront, Cinema, Exhibition space, Museum, Festival space Back A site of production, practice or business management Office, Studio, Rehearsal Space, Teaching Space, Factory, Recording Studio Networking A space to meet clients or others involved in creative industries Meeting places Supply Spaces where supplies for creative work are sourced Supplier, Photoshoot Location, Story Location, Shoot Location, Storage Coding data into discrete units and formulating a typology is a reductive process, thus a number of caveats apply to this analysis. First there were numerous cases where worksites fell across multiple categories. This was particularly the case with practitioners from the music and performing arts sector whose works are created and consumed at the same location, or a clothing designer whose studio is also their shopfront. To avoid double counting, these cases were assigned to one category only, usually split in favour of the site’s main function (i.e. performance sites to Front spaces). During interviews, participants were asked to locate parts of Darwin they went to for work, rather than detail the exact role or name for each of those spaces. While most participants were forthcoming and descriptive in their responses, in two percent of cases (n=11) the role of that particular space was undefined. These spaces were placed into the “back” category. Additionally, the data was coded to refer to individual location instances aggregated to the SLA level, and does not take into account the role of specific facilities within suburbs, even though certain spaces were referred to regularly in the transcripts. It was often the case that a front space for one creative industry practitioner was a key production site for another, or operated simultaneously as a networking site for both. Future disaggregated analyses will tease out the important roles that individual venues play in Darwin’s creative economy, but are beyond this article’s scope. Finally, this analysis is only a snapshot in time, and captures some of the ephemeral and seasonal aspects of creative workplaces in Darwin that occurred around the time of interviewing. To illustrate, there are instances of photographers indicating photo shoot locations, sites that may only be used once, or may be returned to on multiple occasions. As such, if this exercise were to be carried out at another time, a different geography may result. Results A cross-tabulation of the workplace typology against major and minor locations is given in Table 2. Only 20 per cent of worksites were designated as major worksites with the remaining 80 per cent falling into the minor category. There was a noticeable split between Back and Front spaces and their Major/Minor designation. 77 per cent of back spaces were major locations, while the majority of Front spaces (92 per cent) fell into the minor category. The four most frequently occurring Minor Front spaces – client location, performance space, markets and gallery – collectively comprise one third of all workplaces for participants, pointing to their important role as interfacing spaces between creative output produced or worked on elsewhere, and wider publics/audiences. Understandably, all supply sites and networking places were categorised as minor, with each making up approximately 20 per cent of all workplaces. Table 2: creative workplaces cross tabulated against primary and secondary workplaces and divided by creative workplace typology. Major Minor Grand Total Back Office 44 1 45 Studio 22 - 22 Rehearsal Space 7 11 18 Undefined - 11 11 Teaching Space 3 1 4 Factory 1 - 1 Recording Studio 1 - 1 Leanyer Swamp 1 - 1 Back space total 79 24 103 Front Client Location - 70 70 Performance Space 2 67 69 Market 1 11 12 Gallery 3 8 11 Site - 8 8 Shopfront 1 3 4 Exhibition Space - 3 3 Cinema 2 1 3 Museum 1 1 2 Shop/Studio 1 - 1 Gallery and Office 1 - 1 NightClub 1 - 1 Festival space - 1 1 Library 1 - 1 Front Space total 14 173 187 Networking Meeting Place - 94 94 Networking space total - 94 94 Supply Supplier - 52 52 Photoshoot Location - 14 14 Story Location - 9 9 Shoot Location - 7 7 Storage - 4 4 Bank - 1 1 Printer - 1 1 Supply Space total - 88 88 Grand Total 93 379 472 The maps in Figures 1 through 4 analyse the results spatially, with individual SLA scores provided in Table 3. The maps use location quotients, representing the diversion of each SLA from the city-wide average. Values below one represent a less than average result, values greater than one reflecting higher results. The City-Inner SLA maintains the highest overall percentage of Darwin’s creative worksites (35 per cent of the total) across three categories, Front, Back and especially Networking sites (60 per cent). The concentration of key arts institutions, performance spaces and CBD office space is the primary reason for this finding. Additionally, the volume of hospitality venues in the CBD made it an amenable place to conduct meetings away from major back spaces. Figure 1: Back spaces by Statistical Local Areas Figure 2: Front spaces by Statistical Local Areas Figure 3: Networking sites, by Statistical Local Areas Figure 4: Supply sites by Statistical Local Areas However this should not deter from the fact that the majority of all worksites (65 per cent) indicated by participants actually reside in suburban locations. Numerically, the vast majority (70 per cent) of Darwin’s Front spaces are peppered across the suburbs, with agglomerations occurring in The Gardens, Fannie Bay, Nightcliff and Parap. The Gardens is the location for Darwin’s biggest weekly market (Mindl Beach night market), and a performance space for festivals and events during the city’s long dry season. Mirroring more the cultures of its neighbouring SE Asian counterparts, Darwin sustains a vibrant market culture unlike that of any other Australian capital city. As the top end region is monsoonal, six months of the year is guaranteed to be virtually rain free, allowing for outdoor activities such as markets and festivals to flourish. Markets in Darwin have a distinctly suburban geography with each of the three top suburban SLAs (as measured by Front spaces) hosting a regular market, each acting as temporary sites of networking and encounter for creative producers and audiences. Importantly, over half of the city’s production sites (Back spaces) were dispersed across the suburbs in two visible arcs, one extending from the city taking in Fannie Bay and across to Winnellie via Parap, and through the northern coastal SLAs from Coconut Grove to Brinkin (Figure 1). Interestingly, 85 per cent of all supply points were also in suburban locations. Figure 4 maps this suburban specialisation, with the light industrial suburb of Winnellie being the primary location for Darwin’s creative practitioners to source supplies. Table 3: Top ten suburbs by workplace mentions, tabulated by workplace type* SLA name Front Back Networking Supply Workplace total Inner City/CBD City - Inner 56 (29.9%) 35 (36%) 57 (60.6%) 13 (14.8%) 162 (34.3%) Inner City Total 56 (29.9%) 35 (36%) 57 (60.6%) 13 (14.8%) 162 (34.3%) Top 10 suburban The Gardens 30 (16%) 3 (2.9%) 6 (6.4%) 5 (5.7%) 44 (9.3%) Winnellie 3 (1.6%) 7 (6.8%) 1 (1.1%) 24 (27.3%) 35 (7.4%) Parap 14 (7.5%) 4 (3.9%) 6 (6.4%) 9 (10.2%) 33 (7%) Fannie Bay 17 (9.1%) 5 (4.9%) 4 (4.3%) 2 (2.3%) 28 (5.9%) Nightcliff 14 (7.5%) 7 (6.8%) 2 (2.1%) 4 (4.5%) 27 (5.7%) Stuart Park 4 (2.1%) 8 (7.8%) 4 (4.3%) 4 (4.5%) 20 (4.2%) Brinkin 1 (0.5%) 8 (7.8%) 9 (9.6%) 2 (2.3%) 20 (4.2%) Larrakeyah 5 (2.7%) 5 (4.9%) 1 (1.1%) 3 (3.4%) 14 (3%) City - Remainder 5 (2.7%) 2 (1.9%) 0 (0%) 6 (6.8%) 13 (2.8%) Coconut Grove 3 (1.6%) 4 (3.9%) 1 (1.1%) 4 (4.5%) 12 (2.5%) Rapid Creek 3 (1.6%) 6 (5.8%) 0 (0%) 0 (0%) 9 (1.9%) Suburban Total** 131 (70.1%) 67 (65%) 37 (39.4%) 75 (85%) 310 (65.7%) City-Wide Total 187 103 94 88 472 *All percentages calculated from city- wide total **Suburban total row includes all 27 suburbs, not just top tens Discussion There are two key points to take from this analysis. First, the results show the usefulness of combining in-depth qualitative research with GIS mapping methods. Interviewing creative workers about where activities in their working days (or nights) take place, rather than defaulting to incomplete industry statistics can reveal a more comprehensive view of where creative work manifests in the city. Second, the role that multiple, decentred and often suburban facilities played as sites of supply, production and consumption in Darwin’s creative economy leads theories about the spatiality of creativity in the city in new directions. These results clearly show that the cultural binaries that theorists have assumed shape perceptions of the city and its suburbs do not appear in this instance to be infusing the everyday nature of creative work in the city. What was revealed by this data is that creative work in the city creates a variegated city produced through practitioners’ ordinary daily activities. Creative workers are not necessarily resisting or reinventing ideas of what the suburbs mean, they are getting on with creative work in ways that connect suburbs and the city centre in complex – and yet sometimes quite prosaic – ways. This is not to say that the suburbs do not present challenges for the effective conduct of creative work in Darwin – transport availability and lack of facilities were consistently cited problems by practitioners – but instead what is argued here is that ways of understanding the suburbs (in popular discourse, and in response in critical cultural theory) that emanate from Sydney or Los Angeles do not provide a universal conceptual framework for a city like Darwin. By not presuming that there is a meta-discourse of suburbs and city centres that everyone in every city is bound to, this analysis captured a different geography. In conclusion, the case of Darwin displayed decentred and dispersed sites of creativity as the norm rather than the exception. 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