Darwin Area Research Articles

Reducing the Cooling Loads of Buildings Using Shading Devices: A Case Study in Darwin

It is estimated that almost 40% of the world’s energy is consumed by buildings’ heating, ventilation, and air conditioning systems. This consumption increases by 3% every year and will reach 70% by 2050 due to rapid urbanisation and population growth. In Darwin, building energy consumption is even higher and accounts for up to 55% due to the hot and humid weather conditions. Singapore has the same weather conditions but less energy consumption, with only 38% compared to Darwin. Solar radiation can be defined as electromagnetic radiation emitted by the Sun and the Darwin area receives a large amount of solar radiation; building energy consumption can be reduced hugely if this radiation is blocked effectively by analysing appropriate shading devices. This study investigated the influence of different types of shading devices on the cooling load of a town hall building located in Darwin, Australia, and proposed the optimal shading device. The results showed that the horizontal fins led to a 5% reduction in the cooling load of the building. In contrast, adding a variation to the device angles and length increased the savings to 8%. The results demonstrated that the overhangs were more efficient than the fins, contributing 9.2% energy savings, and the cooling reduction savings were increased to 15.5% with design and length variations.

Macroclimatic conditions as main drivers for symbiotic association patterns in lecideoid lichens along the Transantarctic Mountains, Ross Sea region, Antarctica

Lecideoid lichens as dominant vegetation-forming organisms in the climatically harsh areas of the southern part of continental Antarctica show clear preferences in relation to environmental conditions (i.e. macroclimate). 306 lichen samples were included in the study, collected along the Ross Sea coast (78°S–85.5°S) at six climatically different sites. The species compositions as well as the associations of their two dominant symbiotic partners (myco- and photobiont) were set in context with environmental conditions along the latitudinal gradient. Diversity values were nonlinear with respect to latitude, with the highest alpha diversity in the milder areas of the McMurdo Dry Valleys (78°S) and the most southern areas (Durham Point, 85.5°S; Garden Spur, 84.5°S), and lowest in the especially arid and cold Darwin Area (~ 79.8°S). Furthermore, the specificity of mycobiont species towards their photobionts decreased under more severe climate conditions. The generalist lichen species Lecanora fuscobrunnea and Lecidea cancriformis were present in almost all habitats, but were dominant in climatically extreme areas. Carbonea vorticosa, Lecidella greenii and Rhizoplaca macleanii were confined to milder areas. In summary, the macroclimate is considered to be the main driver of species distribution, making certain species useful as bioindicators of climate conditions and, consequently, for assessing the consequences of climate change.

Taxonomic revision of Australasian diving beetles in the genus Leiodytes Guignot, 1936 (Coleoptera: Dytiscidae, Bidessini).

Bidessus migrator Sharp, 1882, so far assigned to Clypeodytes Régimbart, 1894, and widely distributed in Australia and New Guinea, is re-described. Based on morphological and molecular evidence, it is here transferred to Leiodytes Guignot, 1936. Bidessus loriae Régimbart, 1892 is found to be a junior subjective synonym of L. migrator. We describe the following new species: Leiodytes surianiae sp. nov. (eastern New Guinea, northeast coast of Queensland), and Leiodytes wattsi sp. nov. (southern New Guinea and Darwin area to northern Queensland). We delineate the species using characters such as male genital structure and beetle size, shape and color pattern. Mitochondrial Cox1 data for 27 individuals, representing all three Australasian species, were generated and revealed clusters congruent with the morphological evidence. In Australia Leiodytes only occurs in the tropical and subtropical northern part of the continent. None of the species is endemic to Australia. The species are mainly lentic, occurring in seasonal swamps, flooded meadows and pools of intermittent rivers and temporary creeks.

Has mandatory fortification with iodine made a difference? Results from two cohort studies in the Darwin area

Has mandatory fortification with iodine made a difference? Results from two cohort studies in the Darwin area

A Boom for Whom? Exploring the Impacts of a Rapid Increase in the Male Population Upon Women’s Services in Darwin, Northern Territory

A rapidly expanding natural-resource extraction industry and a growing military presence mean an increasingly male-skewed population for the city of Darwin, Australia. This has sparked concerns about the potential for increased violence against women. In this article, we present qualitative research detailing the views of 13 participants from 10 women's support services in the Darwin area. We argue that women's support services bear witness to and are tasked with responding to the impacts of population change on women, yet their work is undermined by uncertainties that stem from neoliberal funding rationales and limited demands on companies to address social issues.

First results from the generation and assimilation of 10-minute atmospheric motion vectors in the Australian region

Ten-minute interval infrared and visible satellite images, available from MTSAR-1R (Himawari-6) for a limited period over and around Australia, have been used to generate atmospheric motion vectors. These vectors—which were available every 10 minutes—have been quality controlled, error characterised and assimilated into the Australian Bureau of Meteorology's next generation operational regional forecast model as part of the new operational database. Results from this study indicate that this high temporal resolution imagery has the ability to produce high spatial and temporal density atmospheric motion vectors, and the quality of these vectors is such that they have the potential to improve numerical analysis and prognosis. In late 2013 and early 2014 the Japanese Meteorological Agency (JMA) provided several months of MTSat-1R rapid scan imagery in support of the 2014 High Altitude Ice Crystal (HAIC) – High Ice Water Content (HIWC) field campaign in the Darwin area. This 10-minute imagery was also provided in support of activities in preparation for Himawari-8. The imagery was renavigated, calibrated and used to generate atmospheric motion vectors (AMVs) over much of the Australian region including the HAIC-HIWC test area. Each vector was error characterised and assigned an expected error. In preparation for the operational assimilation of 10-minute data from the full disk footprint of Himawari-8, these high temporal and spatial resolution data generated over the Australian region test area were combined with the operational database—including high spatial but lower temporal density local Bureau and also JMA AMV data from MTSat-2—to provide forecasts using the next generation operational regional forecast model ACCESS APS2. This model will be used during the introduction of operational Himawari-8 data. First results from these tests indicate the 10-minute data have the potential to produce high density, high quality AMVs which will improve model initialisation and forecasts. This includes cases associated with extreme weather. The results have also provided indications of appropriate timing, data selection and application methods for the effective use of these high temporal resolution data. The quality and density of the 10-minute MTSat-1R data have also been compared to that available from imagery using a new processing paradigm which is to be used in future for the operational Himawari-8 AMV generation.

The Rate of Lexical Change in Australia: Evidence from Larrakia

A paper by Barry Alpher compared earlier and later attestations of Australian languages in ways that may seem to suggest that lexical change in Australia could be unusually rapid, despite Alpher's own disclaimers about the problematic nature of such evidence. The present paper first relates this possibility to recent work in lexically-based language classification and dating. It then proceeds to show that comparing earlier and later attestations of the Larrakia language, of the Darwin area, could also suggest rapid change if the attestations are considered individually, but that all evidence considered together suggests that the Larrakia lexicon was actually quite stable during this period. This casts doubts on what we might hope to learn about the rate of lexical change from comparisons of attestations of languages more poorly attested than Larrakia.

Mating strategy of Oecophylla smaragdina (Hymenoptera: Formicidae) in northern Australia

AbstractThe aim of this study was to elucidate the mating strategy of Oecophylla smaragdina (Fabricius, 1775) and to clarify the factors that related to the nuptial flight. The nuptial flight was investigated over three seasons in the Darwin area, Australia, in which a total of 19 swarmings were observed. All swarmings were observed on days where no rain fell before 15:00 h, and with wind speed ≤18 km/h. On days of swarming air pressure was significantly higher (mean ± SD: 1009.3 ± 1.6 hPa) than on rainless days without swarming (mean ± SD: 1006.9 ± 1.2 hPa). Several swarmings took place during the season, and the production of alate queens occurred more or less continuously over a period of at least 2 months. Therefore, the number of individuals in each swarming depends on the time elapsed since the last swarming. Swarming commenced with males gathering on the external surfaces of nests at sunrise, and about 15 min later they started departing, which took about 10 min. When the males commenced flying the females came out of the nests. When most males had flown, the females started flying, which also took about 10 min. Both males and females flew straight up towards an opening in the canopy. After swarming, alate queens were observed coming down to the canopy after 15–20 min. No queens were found in artificial queen traps 2 h after swarming. A few queens were observed flying around 13:00 h, and later in the afternoon many fertilised queens were found in queen traps. From field observation and laboratory experiments, we conclude that it is most plausible that alate queens meet the males in the air, proceed to the tree canopy to conclude the mating, and then after midday the mated alate queens fly individually to find a nesting site.

Open for Business but at What Cost? Housing issues in ‘boomtown’ Darwin

ABSTRACTThe Greater Darwin area has long experienced high housing costs and high rates of homelessness. Into this already stressed housing context have come large-scale, natural resource development projects, which are predicted to bring thousands of new workers to town, and exciting property investor interest. While many view these developments as positive, there is concern about the impacts upon the most vulnerable members of the population. This paper presents the findings of a qualitative research project exploring current housing issues in the Greater Darwin area. Interviews with housing support service providers and real estate agents reveal that the current population and investment growth have exacerbated longstanding housing issues. Increased housing stress in Darwin, and a myopic focus on rapid economic growth, may disenfranchise current residents and undermine service and support industries. We argue that while there may be some economic benefits from a ‘booming’ Darwin, greater planning and partnership between government, community organisations and corporates is required to ensure the benefits are spread across the population. Unfortunately, the Northern Territory government's dilatory approach to both housing issues and the social costs of the resources boom makes it highly unlikely innovative partnerships will occur.

Remarks on the spatial distribution of some butterflies and diurnal moths (Lepidoptera) in the Top End of the Northern Territory, Australia

The geographical distribution is reviewed and/or new spatial data are given for 15 species of butterflies and diurnal moths from the Top End of the Northern Territory. Three species of day-flying moths, the Zodiac Moth (Alcides metaurus) (family Uraniidae), Mimeusemia centralis (Noctuidae) and Euchromia creusa (Arctiidae), are recorded from the Northern Territory for the first time. Two extant locations of the Purple Beak butterfly (Libythea geoffroyi) from Fish River Station and Gregory National Park represent the first confirmed resident breeding populations of this species in the Northern Territory. The Monarch (Danaus plexippus) is recorded for the first time from the Top End and western Gulf Country where a large-scale range expansion occurred during April-May 2013; other records from the Darwin area comprise intentional introductions facilitated by 'butterfly releases'. New records of the Plain Tiger (Danaus chrysippus) and Northern Argus (Junonia erigone) suggest these species have limited ranges in northern Australia; both are considered to be rare vagrants or immigrants from Indonesia, East Timor, or adjacent islands. The White Migrant (Catopsilia pyranthe) appears to be a rare seasonal migrant to the Darwin area and nearby locations from further inland. The White-banded Line-blue (Nacaduba kurava) is confirmed as occurring in the Darwin area. The Samphire Blue (Theclinesthes sulpitius) and the Glistening Line-blue (Sahulana scintillata) are newly recorded from the western Gulf of Carpentaria and Gove Peninsula, respectively, extending their distribution considerably further east in the Top End. In contrast, the Plumbago Blue (Leptotes plinius) is considered to be erroneous, and accordingly this species is removed from the lepidopteran inventory for the Top End. The Orchard Swallowtail (Papilio aegeus), No-brand Grass-yellow (Eurema brigitta) and Lurcher (Yoma sabina) have narrower ranges within the Northern Territory than previously suspected, being restricted to north-eastern Arnhem Land and/or the Gulf of Carpentaria. Within the Top End, six species, including the Gove Crow (Euploea alcathoe enastri), are restricted to northeastern Arnhem Land, but three others, A. metaurus, E. brigitta, and Red-banded Jezebel (Delias mysis), are probably rare vagrants from northern Queensland.

Expecting a boomtown? Exploring potential housing - related impacts of large scale resource developments in Darwin

Darwin is a city in the Northern Territory of Australia expecting a 'boomtown' scenario due to significant natural resource developments in the Greater Darwin area. The experience of 'booming' has a range of impacts upon communities. Housing is a key area of impact, particularly for the most vulnerable members of a population, who may not reap the benefits of the 'boom'. In Darwin, new resource developments will begin in the context of record high house prices, high rents and high homelessness rates. This literature review explores what is known about the housing-related impacts of boomtowns and considers the likely housing-related impacts of a boomtown scenario in Darwin. While the city's diverse economy and population size may provide some insulation from severe boomtown impacts, housing availability and affordability is likely to be negatively impacted. The implications of this for the most vulnerable members of the greater Darwin population require careful consideration.

Invasive parasites in multiple invasive hosts: the arrival of a new host revives a stalled prior parasite invasion

The success of a biological invasion can depend upon other invasions; and in some cases, an earlier invader may fail to spread until facilitated by a second invader. Our study documents a case whereby an invasive parasite has remained patchily distributed for decades due to the fragmented nature of available hosts; but the recent arrival of a broadly distributed alternative invasive host species provides an opportunity for the parasite to expand its range considerably. At least 20 years ago, endoparasitic pentastomids (Raillietiella frenata) were brought with their native host, the invasive Asian house gecko Hemidactylus frenatus, to the port city of Darwin in tropical Australia. These geckos rarely disperse away from human habitation, restricting the transmission of their parasites to urban environments – and thus, their pentastomids have remained patchily distributed and have only been recorded in scant localities, primarily surrounding Darwin. The recent range expansion of the invasive cane toad Rhinella marina into the Darwin area has provided an alternative host for this pentastomid. Our results show that the cane toad is a competent host for Ra. frenata– toads shed fully embryonated pentastomid eggs in their faeces – and that pentastomids are now common in cane toads near Darwin. Likely reflecting the tendency for the parasite's traditional definitive host (the Asian house gecko) and only known intermediate host (the cockroach) to reside around buildings, we found the prevalence of this parasite follows an urban distribution. Because cane toads are widely distributed through urban and rural habitat and can shed viable pentastomid eggs, the toad invasion is likely to facilitate the parasite's spread across the tropics, into areas (and additional susceptible hosts) that were previously inaccessible to it.

Absence of black parlatoria scale,Parlatoria ziziphi(Lucas) (Hemiptera: Diaspididae) from Australia

The black parlatoria scale, Parlatoria ziziphi, is considered to be absent from Australia despite previous reports of its presence in the Darwin area of the Northern Territory in 1914 and 1915.Asearch of the National Australian Plant Pest Database revealed the existence of only five samples of this species from Australia, three samples from Darwin and two further collections from interceptions likely at the international quarantine border in Sydney. Intensive plant pest surveillance activities over the past 20 years, which included specific surveys for P. ziziphi, have not detected this pest species in the Darwin area or any other region of Australia. It is probable that the scale was incidentally eliminated from the country during an eradication program for citrus canker that, between 1916 and 1922, removed all known citrus plants in the Northern Territory above latitude 19°S.

Biological control of the fruit‐spotting bug Amblypelta lutescens using weaver ants Oecophylla smaragdina on African mahoganies in Australia

African mahogany Khaya senegalensis is a high‐value timber tree. Pilot plantings showed that the fruit‐spotting bug Amblypelta lutescens causes severe damage of the tree in the wet–dry tropics of northern Australia. The weaver ant Oecophylla smaragdina is an efficient biocontrol agent in some horticulture crops. To investigate whether the ants control this pest, field experiments were conducted from April 2006 to January 2009 at two study sites in the Darwin area, Australia. A laboratory experiment was carried out in March 2007 at Berrimah Farm. During the experimental period, in the weaver ant treatments, the overall percentage of trees damaged by the pest was 0–8% at both sites, and the damaged trees were attacked once only. In the treatments without weaver ants, however, the damage level was > 80% at Berrimah Farm and 31–100% at Howard Springs, and the damaged trees were attacked more than once. The mean percentage of trees damaged per monitoring occasion was 0–2.6% in the weaver ant treatments at both sites, whereas, in the treatments without the ants, the damage percentages were 14.2–27.0% at Howard Springs and 28.2–48.6% at Berrimah Farm. Extrafloral nectar of African mahoganies is attractive to weaver ants. Fruit‐spotting bugs only damage the tender parts of flushing shoots and growing tips. Weaver ants live on sugar solution and meat, and they frequently harvest extrafloral nectar on growing shoots, on which they catch nymphs of the pest for their meat supply. The aggressive behaviour of the ants also repels the pest away from flushing shoots. The data suggest that weaver ants were effective biocontrol agents of fruit‐spotting bugs, and the ants can be used to manage the pest on African mahoganies. The present study demonstrates that the introduced African mahogany comprises another major host of the fruit‐spotting bug.

Anthropogenic Ecological Change and Impacts on Mosquito Breeding and Control Strategies in Salt-Marshes, Northern Territory, Australia

Darwin, in the tropical north of Australia, is subject to high numbers of mosquitoes and several mosquito-borne diseases. Many of Darwin's residential areas were built in close proximity to tidally influenced swamps, where long-term storm-water run-off from nearby residences into these swamps has led to anthropogenic induced ecological change. When natural wet-dry cycles were disrupted, bare mud-flats and mangroves were transformed into perennial fresh to brackish-water reed swamps. Reed swamps provided year-round breeding habitat for many mosquito species, such that mosquito abundance was less predictable and seasonally dependent, but constant and often occurring in plague proportions. Drainage channels were constructed throughout the wetlands to reduce pooled water during dry-season months. This study assesses the impact of drainage interventions on vegetation and mosquito ecology in three salt-marshes in the Darwin area. Findings revealed a universal decline in dry-season mosquito abundance in each wetland system. However, some mosquito species increased in abundance during wet-season months. Due to the high expense and potentially detrimental environmental impacts of ecosystem and non-target species disturbance, large-scale modifications such as these are sparingly undertaken. However, our results indicate that some large scale environmental modification can assist the process of wetland restoration, as appears to be the case for these salt marsh systems. Drainage in all three systems has been restored to closer to their original salt-marsh ecosystems, while reducing mosquito abundances, thereby potentially lowering the risk of vector-borne disease transmission and mosquito pest biting problems.

Model Study of Intermediate-Scale Tropical Inertia–Gravity Waves and Comparison to TWP-ICE Campaign Observations

Abstract A 2-day inertia–gravity wave (IGW) was observed in high-resolution radiosonde soundings of horizontal wind and temperature taken during the 2006 Tropical Warm Pool–International Cloud Experiment (TWP-ICE) experiment in the Darwin area. The wave was observed in the stratosphere above Darwin from 28 January to 5 February. A similar wave event is observed in the European Centre for Medium-Range Weather Forecasts (ECMWF) operational data. A comparison between the characteristics of the IGW derived with the ECMWF data to the properties of the wave derived with the radiosonde data shows that the ECMWF data capture similar structure for this 2-day wave event but with a larger vertical wavelength. A reverse ray-tracing method is used to localize the source region. Using ECMWF data to define the atmospheric background conditions and wave properties observed in the soundings, it is found that the 2-day wave event originated from deep convection in the Indonesian region around 20 January. The Weather Research and Forecasting (WRF) modeling system is used to complement the ECMWF data to assess the influence of vertical resolution and initial conditions on the wave structure. The model domain is configured as a tropical channel and the ECMWF analyses provide the north/south boundaries and initial conditions. WRF is used with the same horizontal resolution (40 km) as the operational ECMWF in 2006 while using a finer vertical grid spacing than ECMWF. The model is run from 18 January to 11 February to cover the wave life cycle. Different experiments are also performed to determine the sensitivity of the wave structure to cumulus schemes, initial conditions, and vertical resolution. The 2-day wave properties resulting from the WRF experiments are compared to those retrieved from the radiosonde data and from the ECMWF analyses. It is demonstrated that higher vertical resolution would be required for ECMWF to accurately resolve the vertical structure of the wave and its effect on the middle-atmospheric circulation.

A simultaneous journal / wiki publication and dissemination of a new species description: Neobidessodes darwiniensis sp. n. from northern Australia (Coleoptera, Dytiscidae, Bidessini)

Here, we describe a new Australian species in journal format and simultaneously open the description in a wiki format on the www.species-id.net. The wiki format will always link to the fixed original journal description of the taxon, however it permits future edits and additions to species' taxonomy and biology. The diving beetle Neobidessodes darwiniensis sp. n. (Coleoptera: Dytiscidae, Bidessini) is described based on a single female, collected in a rest pool of the Harriet Creek in the Darwin Area, Northern Territory. Within Neobidessodes the new species is well characterized by its elongate oval body with rounded sides, short and stout segments of antennae, length of body and dorsal surface coloration. In addition to external morphology, we used mitochondrial cox1 sequence data to support generic assignment and to delineate the new species from other Australian Bidessini including all other known Neobidessodes. Illustrations based on digital images are provided here and as online resources. A modified key is provided. Altogether ten species of the genus are now known worldwide, nine from Australia and one from New Guinea.

Diversity ofLecidea(Lecideaceae, Ascomycota) species revealed by molecular data and morphological characters

AbstractThe diversity of lichens, especially crustose species, in continental Antarctica is still poorly known. To overcome difficulties with the morphology based species delimitations in these groups, we employed molecular data (nuclear ITS and mitochondrial SSU rDNA sequences) to test species boundaries within the genusLecidea.Sampling was done along a north–south transect at five different areas in the Ross Sea region (Cape Hallett, Botany Bay to Mount Suess, Taylor Valley, Darwin Area and Mount Kyffin). A total of 153 specimens were collected from 13 localities. Phylogenetic analyses also include specimens from other regions in Antarctica and non-Antarctic areas. Maximum parsimony, maximum likelihood and Bayesian analyses agreed in placing the samples from continental Antarctica into four major groups. Based on this phylogenetic estimate, we restudied the micromorphology and secondary chemistry of these four clades to evaluate the use of these characters as phylogenetic discriminators. These clades are identified as the following speciesLecidea cancriformis,L. andersoniias well as the new speciesL. polypycnidophoraRuprecht & Türk sp. nov. and another previously unnamed clade of uncertain status, referred to asLecideasp. (L.UCR1).

Weaver ants, Oecophylla smaragdina (Hymenoptera: Formicidae), as biocontrol agents on African mahogany trees, Khaya senegalensis (Sapindales: Meliaceae), in the Northern Territory of Australia

African mahogany, Khaya senegalensis, is a high quality timber tree that grows well in the wet-dry tropical areas of Australia. Most trees grown in the latter regions are branched at lower levels on the trunk (a symptom known as ‘low-branching’), which limits timber production per tree. Inferring that it may be caused by herbivorous insects, we sought to establish whether low-branching can be reduced by the presence of predatory weaver ants, Oecophylla smaragdina. Two field experiments on young African mahoganies were conducted at two sites in the Darwin area of Australia from 2006 to 2008. Each experiment had two treatments: trees with weaver ants and trees without the ants. Pest damage was found to be the most important correlate of the multiple branching, and weaver ants were effective in limiting the formation of multiple leaders. In 3-year-old mahoganies at Berrimah Farm, the percentage of trees with pest-caused multiple leaders was 4.8% in the weaver ant treatments (WAT) but 45.5% in the treatments without the ants (TWWA). In 2-year-old mahogany coppices at Howard Springs, no trees developed multiple leaders in WAT, but 22% developed such leaders in TWWA. The average pest damage on flushing shoots at both sites was significantly lower in WAT (1.8–2.5%) than in TWWA (22.9–24.9%).

Lightning characteristics observed by a VLF/LF lightning detection network (LINET) in Brazil, Australia, Africa and Germany

Abstract. This paper describes lightning characteristics as obtained in four sets of lightning measurements during recent field campaigns in different parts of the world from mid-latitudes to the tropics by the novel VLF/LF (very low frequency/low frequency) lightning detection network (LINET). The paper gives a general overview on the approach, and a synopsis of the statistical results for the observation periods as a whole and for one special day in each region. The focus is on the characteristics of lightning which can specifically be observed by this system like intra-cloud and cloud-to-ground stroke statistics, vertical distributions of intra-cloud strokes or peak current distributions. Some conclusions regarding lightning produced NOx are also presented as this was one of the aims of the tropical field campaigns TROCCINOX (Tropical Convection, Cirrus and Nitrogen Oxides Experiment) and TroCCiBras (Tropical Convection and Cirrus Experiment Brazil) in Brazil during January/February 2005, SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) and TWP-ICE (Tropical Warm Pool-International Cloud Experiment) during November/December 2005 and January/February 2006, respectively, in the Darwin area in N-Australia, and of AMMA (African Monsoon Multidisciplinary Analyses) in W-Africa during June–November 2006. Regional and temporal characteristics of lightning are found to be dependent on orographic effects (e.g. S-Germany, Brazil, Benin), land-sea breeze circulations (N-Australia) and especially the evolution of the monsoons (Benin, N-Australia). Large intra-seasonal variability in lightning occurrence was found for the Australian monsoon between the strong convection during build-up and break phases and the weak active monsoon phase with only minor lightning activity. Total daily lightning stroke rates can be of comparable intensity in all regions with the heaviest events found in Germany and N-Australia. The frequency of occurrence of such days was by far the largest in N-Australia. In accordance with radar observed storm structures, the intra-cloud stroke mean emission heights were found distinctly different in Germany (8 km) as compared to the tropics (up to 12 km in N-Australia). The fraction of intra-cloud strokes (compared to all strokes) was found to be relatively high in Brazil and Australia (0.83 and 0.82, respectively) as compared to Benin and Germany (0.64 and 0.69, respectively). Using stroke peak currents and vertical location information, lightning NOx (LNOx) production under defined standard conditions can be compared for the different areas of observation. LNOx production per standard stroke was found to be most efficient for the N-Australian and S-German thunderstorms whereas the yield from Brazilian and W-African strokes was nearly 40% less. On the other hand, the main NO contribution in Brazil was from intra-cloud (IC) strokes whereas in Benin it was due to cloud-to-ground (CG) components. For the German and Australian strokes both stroke types contributed similar amounts to the total NO outcome.