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This study assessed whether dust-storm frequency during major droughts in New South Wales (NSW), Australia, has changed and what may have caused any change. The frequency of days with dust storms, i.e. when visibility is

Dust emissions influence global climate while simultaneously reducing the productive potential and resilience of landscapes to climate stressors, together impacting food security and human health. Vegetation is a major control on dust emission because it extracts momentum from the wind and shelters the soil surface, protecting dry and loose material from erosion by winds. Many of the current dust emission models (TEM) assume that the Earth’s land surface is constantly devoid of vegetation, then adjust the dust emission using a vegetation cover reciprocal, and finally calibrate to dust in the atmosphere. We compare this approach with an albedo-based dust emission model (AEM) which calibrates Earth’s land surface shadow to shelter depending on wind speed, to represent aerodynamic roughness spatio-temporal variation. We also compare these dust emission models with estimates of dust in the atmosphere using dust optical depth frequency (DOD). Using existing datasets of satellite observed dust emission from dust point sources (DPS), we show that during the same period, DOD frequency exceeds DPS frequency by up to two orders of magnitude (RMSEDOD = 67 days). Relative to DPS frequency, both models over-estimated dust emission frequency by up to one order of magnitude (RMSETEM = 6 days; RMSEAEM = 4 days) but showed strong relations with DPS frequency suitable for calibrating models to observed dust emission. Theoretically, the TEM is incomplete in its formulation, which despite the pragmatic adjustment using the vegetation cover reciprocal, causes dust emission to be highly dependent on wind speed and over-estimates large (> 0.1 kg m−2 a−1) dust emission over vast vegetated areas. Consequently, the TEM produces considerable falsely positive change in dust emission, relative to the AEM. Since the main difference between the dust emission models is the treatment of aerodynamic roughness we conclude that its crude representation in the TEM has caused large, previously unknown, uncertainty in Earth System Models (ESMs). Our results indicate that tuning dust emission models to dust in the atmosphere has hidden for more than two decades, these TEM modelling weaknesses and its poor performance. The AEM overcomes these weaknesses and improves performance without tuning. In ESMs the AEM can be driven by available prognostic albedo to represent the fidelity of drag partition physics to reduce uncertainty of aerosol effects on, and responses to, contemporary and future environmental change.

Large‐scale geomorphic drivers that operate at continental scale are often climate driven. Changes in land use can accelerate wind erosion. The range of land management practises within one land use can have dramatic effect on ground cover and wind erosion. This study uses meteorological observations, land use, land management and dust concentration measurements of 129 dust events recorded between 1990 and 2007 to describe a dust chronology of Mildura, in south‐eastern Australia. Frontal and frontal trough weather systems account for 74% of dust events. Furthermore, 88% of dust events come from rangelands in the northwest and the cropping lands to the southwest. The cropping areas to the southwest are the most common source of dust, accounting for 66% of events There is no relationship between rainfall and dust activity in this study, suggesting that land‐management practices, especially on cropping lands, over‐ride the controlling effect of rainfall. When cropping lands received above average rainfall in spring and summer during the 1990s, cultivation for weed control lead to rapid decline in ground cover that predisposed the land to wind erosion in following summer and autumn. In drought years, dust blows into Mildura from all directions suggesting that dust is climate driven rather than controlled by land use.

The advanced Himawari imager (AHI) aboard the Himawari-8 geostationary satellite provides high-frequency observations with broad coverage, multiple spectral channels, and high spatial resolution. In this paper, AHI data were used to develop an algorithm for joint retrieval of aerosol optical depth (AOD) over land and land surface bidirectional reflectance. Instead of performing surface reflectance estimation before calculating AOD, the AOD and surface bidirectional reflectance were retrieved simultaneously using an optimal estimation method. The algorithm uses an atmospheric radiative transfer model coupled with a surface bidirectional reflectance factor (BRF) model. Based on the assumption that the surface bidirectional reflective properties are invariant during a short time period (i.e., a day), multiple temporal AHI observations were combined to calculate the AOD and surface BRF. The algorithm was tested over East Asia for year 2016, and the AOD retrieval results were validated against the aerosol robotic network (AERONET) sites observation and compared with the Moderate Resolution Imaging Spectroradiometer Collection 6.0 AOD product. The validation of the retrieved AOD with AERONET measurements using 14 713 colocation points in 2016 over East Asia shows a high correlation coefficient: $R = 0.88$ , root-mean-square error = 0.17, and approximately 69.9% AOD retrieval results within the expected error of $\pm 0.2\cdot {\mathrm {AOD}}_{\mathrm {AERONET}}\pm 0.05$ . A brief comparison between our retrieval and AOD product provided by Japan Meteorological Agency is also presented. The comparison and validation demonstrates that the algorithm has the ability to estimate AOD with considerable accuracy over land.

The Land Degradation-Neutrality (LDN) framework of the United Nations Convention to Combat Desertification (UNCCD) is underpinned by three complementary interactive indicators (metrics: vegetation cover, net primary productivity; NPP and soil organic carbon; SOC) as proxies for change in land-based natural capital. The LDN framework assumes that SOC changes slowly primarily by decomposition and respiration of CO2 to the atmosphere. However, there is growing evidence that soil erosion by wind, water and tillage also reduces SOC stocks rapidly after land use and cover change. Here we modify a physically-based sediment transport model to estimate wind erosion and better represent the vegetation cover (using land surface aerodynamic roughness; that is the plant canopy coverage, stone cover, soil aggregates, etc. that protects the soil surface from wind erosion) and quantify the contribution of wind erosion to global SOC erosion (2001-2016). We use the wind erosion model to identify global dryland regions where SOC erosion by wind may be a significant problem for achieving LDN. Selected sites in global drylands show SOC erosion by wind accelerating over time. Without targeting and reducing SOC erosion, management practices in these regions will fail to sequester SOC and reduce land degradation. We describe the interrelated nature of the LDN indicators, the importance of including SOC erosion by wind erosion and how by explicitly accounting for wind erosion processes, we can better represent the physical effects of changing land cover on land degradation. Our results for Earth’s drylands show that modelling SOC stock reduction by wind erosion is better than using land cover and SOC independently. Furthermore, emphasising the role of wind erosion in UNCCD and Intergovernmental Panel on Climate Change (IPCC) reporting will better support LDN and climate change mitigation and adaptation globally

Hillslope erosion is the dominant form of erosion in Australia and many parts of the world. ‘Tolerable’ hillslope erosion or tolerable soil loss (TSL) targets needs to be established considering the inherent physical capacity of the land to sustain specific land uses and management practices without degradation to soil, land, air and water resources. The existing methods on TSL estimation vary greatly over different regions and applications, and few practical and dynamic methods are available. In this study, we explored a dynamic approach to set TSL and vegetation cover targets across the state of New South Wales (NSW), Australia considering the prevailing hillslope erosion and the sustainable erosion level. Over 20-year fractional vegetation cover and rainfall erosivity time-series have been used to determine the hillslope erosion and the TSL targets monthly and the 50 th percentile was set as the target. Consequently, the monthly vegetation cover levels have been set to sustain the TSL targets on a pixel-by-pixel (100 m) basis. We further assessed the TSL targets against the land and soil capability classes and their spatial and temporal variation across NSW Local Land Services regions. The findings help to identify the locations and times with hillslope erosion exceeding a tolerable threshold value across NSW. This approach is practical, semi-quantitative and portable as the input datasets are widely available, thus providing a useful tool to determine varying TSL values for sustainable soil and land management at any location and period.

Wind erosion and blowing dust threaten food security, human health and ecosystem services across global drylands. Monitoring wind erosion is needed to inform management, with explicit monitoring objectives being critical for interpreting and translating monitoring information into management actions. Monitoring objectives should establish quantitative guidelines for determining the relationship of wind erosion indicators to management benchmarks that reflect tolerable erosion and dust production levels considering impacts to, for example, ecosystem processes, species, agricultural production systems and human well-being. Here we: 1) critically review indicators of wind erosion and blowing dust that are currently available to practitioners; and 2) describe approaches for establishing benchmarks to support wind erosion assessments and management. We find that while numerous indicators are available for monitoring wind erosion, only a subset have been used routinely and most monitoring efforts have focused on air quality impacts of dust. Indicators need to be related to the causal soil and vegetation controls in eroding areas to directly inform management. There is great potential to use regional standardized soil and vegetation monitoring datasets, remote sensing and models to provide new information on wind erosion across landscapes. We identify best practices for establishing benchmarks for these indicators based on experimental studies, mechanistic and empirical models, and distributions of indicator values obtained from monitoring data at historic or existing reference sites. The approaches to establishing benchmarks described here have enduring utility as monitoring technologies change and enable managers to evaluate co-benefits and potential trade-offs among ecosystem services as affected by wind erosion management.

The aerosol monitoring provides air quality information to the community. Policy and community groups often want to know more than the level of mass concentration, that is, a description of what type of aerosols are being reported. There is a need to more objectively and efficiently, that is, in near real time, classify aerosols. Different instruments are used in different networks, raising the issue of comparability. In New South Wales, Australia, the Air Quality monitoring network uses Tapered Element Oscillating Microbalances (TEOM). The Community DustWatch network uses DustTrak® and subjectively classifies its data into dust, smoke and fog. To understand the instrument measurement differences and the aerosols types in Wagga Wagga (New South Wales, Australia), this paper compares paired continuous PM10 measurements from two instruments, the multi-channel DustTrak DRX model 8532 and the TEOM for the period of August 2011 to December 2014. The Reduced Major Axis (RMA) regression was conducted between TEOM PM10 measurements against subjectively classified DustTrak PM10 for different aerosol types. Two methods namely, a single variable DustTrak PM2.5/PM10 ratio (DTPR) method and the Classification and Regression Trees (CART) method were developed to classify the aerosol type into dust, fog and smoke by their particle size distribution (PSD). Based on the thresholds proposed by a single variable DTPR method, the objective classification was conducted on DustTrak data and the RMA regression was rerun. The major finding is that the multi-channel DustTrak DRX model 8532 can be used to classify aerosol type by their average PSD at Wagga Wagga. The aerosol types were classified by two methods: 1) a single variable DTPR is proposed of ≤ 0.55 as a threshold for dust aerosol; 0.55 0.96 for fog. And 2) the CART analysis that uses two variables PM4–10 and DTPR. The initial cut-off of PM4–10 of The PM10 data measured with TEOM and DustTrak have a poor level of agreement no matter if we use the subjectively or objectively classified data. However, the DustTrak PM10 to the TEOM PM10 ratio improves from 0.38 to 0.76 with objectively classified dust data; the ratio of 0.98 gets closer to 1 with objectively classified smoke data; DustTrak PM10 higher by a factor of 2.4 with objectively classified fog data. We were not expecting a good relationship between the two instruments for fog due to the heated inlet on the TEOM. To improve the characterization of aerosol type in the current DustWatch network (or Rural Air Quality Network since 2018), instruments are suggested to be upgraded to multi-channel instruments.

The essential biodiversity variables (EBV) framework was developed primarily to improve the detection of significant changes in global biodiversity. Its application at national level must support county-specific policy and management needs as well as allowing comparisons of estimates of biodiversity change between countries and their aggregation for reporting at regional, continental and global scales. Here we outline a process for prioritising biodiversity variables at national scale using the EBV framework. The process involves separately identifying candidate EBVs that are useful for tracking important changes in biodiversity in each major ecological feature in each ecoregion within a country. The list is then prioritised based on the proportion of ecological feature ecoregion combinations using each variable within and across terrestrial, marine and freshwater realms. We showcased this process in Australian state of New South Wales (NSW) using terrestrial, marine and freshwater ecoregions of the world as bioregional strata; vegetation formations as terrestrial ecological features, and broad aquatic ecosystem types as marine and freshwater ecological features. There was sufficient knowledge of ecological processes to identify useful variables for 85% of the ecological feature ecoregion combinations in NSW. Eleven candidate EBVs covering all six EBV classes, were useful in all three environmental realms. Our structured, stepwise approach to variable selection provides a transparent process for identifying important elements of ecological theory underpinning biodiversity monitoring within countries. Worldwide adoption of a process for prioritising biodiversity variables such as the one we propose here would help ensure consistency of national contributions to global biodiversity assessments.

Connecting people with nature improves well-being, but how people connect with natural places is not well documented. We asked 43 people (19 Aboriginal Australians, 24 non-Aboriginal people) about the messages they received from Country during an interactive experience in the remote Mungo National Park, Australia, and analysed the physical senses, emotions and cognitive processes they mentioned. The physical senses mentioned by most respondents were sight, hearing and motion (particularly walking). These senses helped people receive messages from Country and connect with place. We used the primary-process emotional systems of Panksepp [2010. Dialogues in Clinical Neuroscience, 12 (4), 533–545] as a framework to capture the emotional dimension of experience. Most people reported positive emotions; they spoke about being nurtured by the group and the land (CARE), and the intense joy (PLAY) of being part of the community, being on Country and being accompanied by Aboriginal people. However, our resul...

This editorial represents a clarion call for the aeolian research community to provide increased scientific input to the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Convention to Combat Desertification (UNCCD) and an invitation to apply for ISAR funding to organize a working group to support this engagement.

Wind erosion processes affect soil surfaces across all land uses worldwide. Understanding the spatial and temporal scales of wind erosion is a challenging undertaking because these processes are diverse and highly variable. Wind tunnels provide a useful tool as they can be used to simulate erosion at small spatial scales. Portable wind tunnels are particularly valued because erosion can be simulated on undisturbed soil surfaces in the field. There has been a long history of use of large portable wind tunnels, with consensus that these wind erosion simulation tools can meet real world aerodynamic criteria. However, one consequence of striving to meet aerodynamic reality is that the size of the tunnels has increased, making them logistically difficult to work with in the field and resulting in a tendency to homogenise naturally complex soil surfaces. This homogenisation is at odds with an increasing awareness of the importance that small scale processes have in wind erosion. To address these logistical and surface homogenisation issues we present here the development and testing of a micro wind tunnel (MWT) designed to simulate wind erosion processes at high spatial resolution. The MWT is a duct-type design—0.05 m tall 0.1 m wide and with a 1.0 m working section. The tunnel uses a centrifugal motor to suck air through a flow‐conditioning section, over the working section and then through a sediment collection trap. Simulated wind velocities range from 5 to 18 m s−1, with high reproducibility. Wind speeds are laterally uniform and values of u* at the tunnel bed (calculated by measuring the pressure gradients within the MWT) are comparable with those of larger tunnels in which logarithmic profiles can be developed. Saltation sediment can be added. The tunnel can be deployed by a single person and operated on slopes ranging from 0 to 10°. Evidence is presented here that the MWT provides new and useful understanding of the erodibility of rangelands, claypans and ore stockpiles.

The development of fractional vegetation cover products for Australia that resolve cover into photosynthetic vegetation (FPV), non-photosynthetic vegetation (FNPV) and bare soil/rock (FBS) provides a new basis for examination of responses of vegetation cover to long term precipitation cycles, and to explore the interaction between these responses and land cover type, land use and other land surface properties. In this study, the relationship between accumulated antecedent precipitation (AAP) from 1 to 60 months and average monthly FPV and FNPV from the MODIS Fractional Cover Product is examined over a 17 year period from 2001 to 2018. The maximum R2 value, regression coefficients for the maximum R2, and number of accumulated months to the maximum R2 were mapped for each month of the year for FPV and FNPV. Behaviour of responses in relation to land use, land cover, and soil water holding capacity was analysed based on pixel frequencies of classes at sub-region scale in the Interim Biogeographic Regionalisation of Australia. The analysis showed that FPV is largely dependent upon AAP in the preceding 12 months, however responses to longer periods of AAP also occur in specific land use-vegetation type combinations. The study also showed that positive responses in FNPV could be driven by AAP from as much as 60 months, but that FNPV is reduced in many areas in response to increased AAP. The presence or absence of domesticated livestock grazing as defined by Australian land use mapping was a major influence on response to AAP of both FPV and FNPV with statistical analysis indicating interactions between major natural vegetation type and grazing. In highly responsive areas (R2 > 0.6) monitoring of land condition could be enhanced by testing of regional cover levels for major deviations from the long terms responses that might suggest land management concerns.

Most conservation research aims to inform management of environmental challenges, but scientific evidence is used inconsistently in environmental programmes and practice. We used semi-structured retrospective interviews to ask 12 environmental scientists and 14 practitioners (land managers, park rangers, project managers and planners from natural resource management agencies) about factors that facilitated and hindered the use of scientific input during 15 environmental projects. We used the common factors from interviews to develop a process model describing how scientific input informs programmes and practice. The model emphasised the social dimensions of environmental projects which are often overlooked when these projects are planned, managed and evaluated. It highlighted the pivotal role of relationships in achieving outcomes which include creating practical, useful products and tools, and robust, credible and trusted evidence. By clarifying the process of how scientific knowledge informs environmental programmes and practice, the model enabled us to provide guidance about how to undertake transdisciplinary work and suggest indicators to track progress. Although derived from environmental projects, the guidance is likely to apply to other fields, particularly where different disciplines work together.

Since the pioneering work of Bagnold in the 1940s, aeolian research has grown to become an integral part of earth-system science. Many individuals have contributed to this development, and Dr. Michael R. Raupach (1950–2015) has played a pivotal role. Raupach worked intensively on wind erosion problems for about a decade (1985–1995), during which time he applied his deep knowledge of turbulence to aeolian research problems and made profound contributions with far-reaching impact. The beauty of Raupach’s work lies in his clear conceptual thinking and his ability to reduce complex problems to their bare essentials. The results of his work are fundamentally important and have many practical applications. In this review we reflect on Raupach’s contribution to a number of important aspects of aeolian research, summarise developments since his inspirational work and place Raupach’s efforts in the context of aeolian science. We also demonstrate how Raupach’s work provided a foundation for new developments in aeolian research. In this tribute, we concentrate on five areas of research: (1) drag partition theory; (2) saltation roughness length; (3) saltation bombardment; (4) threshold friction velocity and (5) the carbon cycle.

The roles of pre-frontal, frontal and post-frontal winds as the primary wind systems for dust entrainment and transport in Australia are well established. While the relevance of each system has been observed across different wind erosion events in central Australia, the entrainment of dust by all three winds during the passage of an individual front has not been demonstrated until now. Synoptic information, satellite aerosol and imagery, meteorological and dust concentration data are presented for a single case study erosion event in the lower Lake Eyre Basin. This event demonstrates variable dust transport in three different directions from one of the southern Hemisphere's most significant source regions, and the changing nature of the active dust pathways during the passage of a frontal system. While only a single dust event is considered, the findings show the complexity of mineral aerosol emission and transport patterns even within an individual dust outbreak. For the lower Lake Eyre Basin, this appreciation of pathway behaviour is significant for better understanding the role of aeolian inputs from the dominant Australian source to surrounding marine systems. In a wider context, the findings exhibit the detailed insights into major dust source dynamics that can be obtained from high resolution spatial and particularly temporal data, as used in combination. This work highlights the importance of adequately resolved data for the accurate determination of dust entrainment and transport patterns of major dust sources.

An estimated 110 Mt of dust is eroded by wind from the Australian land surface each year, most of which originates from the arid and semi-arid rangelands. Livestock production is thought to increase the susceptibility of the rangelands to wind erosion by reducing vegetation cover and modifying surface soil stability. However, research is yet to quantify the impacts of grazing land management on the erodibility of the Australian rangelands, or determine how these impacts vary among land types and over time. We present a simulation analysis that links a pasture growth and animal production model (GRASP) to the Australian Land Erodibility Model (AUSLEM) to evaluate the impacts of stocking rate, stocking strategy and land condition on the erodibility of four land types in western Queensland, Australia. Our results show that declining land condition, over stocking, and using inflexible stocking strategies have potential to increase land erodibility and amplify accelerated soil erosion. However, land erodibility responses to grazing are complex and influenced by land type sensitivities to different grazing strategies and local climate characteristics. Our simulations show that land types which are more resilient to livestock grazing tend to be least susceptible to accelerated wind erosion. Increases in land erodibility are found to occur most often during climatic transitions when vegetation cover is most sensitive to grazing pressure. However, grazing effects are limited during extreme wet and dry periods when the influence of climate on vegetation cover is strongest. Our research provides the opportunity to estimate the effects of different land management practices across a range of land types, and provides a better understanding of the mechanisms of accelerated erosion resulting from pastoral activities. The approach could help further assessment of land erodibility at a broader scale notably if combined with wind erosion models.

Australia’s rangeland communities, industries, and environment are under increasing pressures from anthropogenic activities and global changes more broadly. We conducted a horizon scan to identify and prioritise key challenges facing Australian rangelands and their communities, and outline possible avenues to address these challenges, with a particular focus on research priorities. We surveyed participants of the Australian Rangeland Society 20th Biennial Conference, held in Canberra in September 2019, before the conference and in interactive workshops during the conference, in order to identify key challenges, potential solutions, and research priorities. The feedback was broadly grouped into six themes associated with supporting local communities, managing natural capital, climate variability and change, traditional knowledge, governance, and research and development. Each theme had several sub-themes and potential solutions to ensure positive, long-term outcomes for the rangelands. The survey responses made it clear that supporting ‘resilient and sustainable rangelands that provide cultural, societal, environmental and economic outcomes simultaneously’ is of great value to stakeholders. The synthesis of survey responses combined with expert knowledge highlighted that sustaining local communities in the long term will require that the inherent social, cultural and natural capital of rangelands are managed sustainably, particularly in light of current and projected variability in climate. Establishment of guidelines and approaches to address these challenges will benefit from: (i) an increased recognition of the value and contributions of traditional knowledge and practices; (ii) development of better governance that is guided by and benefits local stakeholders; and (iii) more funding to conduct and implement strong research and development activities, with research focused on addressing critical knowledge gaps as identified by the local stakeholders. This requires strong governance with legislation and policies that work for the rangelands. We provide a framework that indicates the key knowledge gaps and how innovations may be implemented and scaled out, up and deep to achieve the resilience of Australia’s rangelands. The same principles could be adapted to address challenges in rangelands on other continents, with similar beneficial outcomes.

There are numerous examples illustrating the integration of Aboriginal knowledge and participation in rangelands management. At the 2019 Australian Rangelands Conference we aimed to explore how Aboriginal culture and its core values have something deeper to contribute to rangelands management. We explore this through a Yungadhu (Malleefowl) cultural depiction and story. The depiction and story explain the often cited, but not well understood, concepts of Kinship, Country, Lore, and Dreaming. The story provides insight into Aboriginal people’s world view and is used in this paper to illustrate how well it aligns with current thinking about resilience in rangelands landscapes and communities. Significantly, we explain how the deep wisdom that resides in Aboriginal cultures has something meaningful to contribute to achieving the conditions for resilience.

Simulations of the dust cycle and its interactions with the changing Earth system are hindered by the empirical nature of dust emission parameterizations in weather and climate models. Here we take a step towards improving dust cycle simulations by using a combination of theory and numerical simulations to derive a physically based dust emission parameterization. Our parameterization is straightforward to implement into large-scale models, as it depends only on the wind friction velocity and the soil's threshold friction velocity. Moreover, it accounts for two processes missing from most existing parameterizations: a soil's increased ability to produce dust under saltation bombardment as it becomes more erodible, and the increased scaling of the dust flux with wind speed as a soil becomes less erodible. Our treatment of both these processes is supported by a compilation of quality-controlled vertical dust flux measurements. Furthermore, our scheme reproduces this measurement compilation with substantially less error than the existing dust flux parameterizations we were able to compare against. A critical insight from both our theory and the measurement compilation is that dust fluxes are substantially more sensitive to the soil's threshold friction velocity than most current schemes account for.

Further developments of a parameterization scheme for convective turbulent dust emission (CTDE) are presented. The scheme is advanced by including (1) a new statistical description of instantaneous momentum flux, (2) a correction function for cohesive force to account for the effect of soil moisture, and (3) a correction function for lifting force to consider the effect of vegetation roughness elements. The probability density function describing instantaneous momentum flux is now derived from large-eddy simulations for different atmospheric stabilities. The vegetation correction function is based on a drag partition theory. Additional improvements on the representations of interparticle cohesive force and particle size distribution are introduced. The new CTDE scheme is tested against the field data obtained at a sand storm monitoring station in the Horqin Sandy Land in China in 2011 and during the Japan-Australia Dust Experiment in Australia in 2006.

This study reports findings on observed visibility reductions and associated concentrations of mineral dust from a detailed Australian case study. An understanding of the relationship between visibility and dust concentration is of considerable utility for wind erosion and aeolian dust research because it allows visibility data, which are available from thousands of weather observation stations worldwide, to be converted into dust concentrations. Until now, this application of visibility data for wind erosion/dust studies has been constrained by the scarcity of direct measurements of co-incident dust concentration and visibility measurements. While dust concentrations are available from high volume air samplers, these time-averaged data cannot be directly correlated with instantaneous visibility records from meteorological observations. This study presents a new method for deriving instantaneous values of total suspended dust from time averaged (filter-based) samples, through reference to high resolution PM10 data. The development and testing of the model is presented here as well as a discussion of the derived expression in relation to other visibility-dust concentration predictive curves. The current study is significant because the visibility-dust concentration relationship produced is based on visibility observations made 10–100 km from the dust sources. This distance from source makes the derived relationship appropriate for a greater number of visibility recording stations than widely-used previous relationships based on observations made directly at eroding sources. Testing of the new formula performance against observed total suspended dust concentrations demonstrates that the model predicts dust concentration relatively well (r2 = 0.6) from visibility. When considered alongside previous studies, the new relationship fits into the continuum of visibility-dust concentration outcomes existing for increasing distance-from-source. This highlights the important influence that distance to source has on the visibility-dust concentration relationship.

Size-resolved dust flux measurements are important for estimation of concentration and physical properties of dust particles in the atmosphere and their impacts on cloud and radiation transfer. In this study, we evaluate the power law relationship between size-resolved dust flux, Fair,d, and friction velocity, u∗. During the Japan–Australia Dust Experiment, size-resolved dust fluxes were estimated with the gradient method by using data from optical particle counters and profile measurements of wind speed and air temperature in a dry, non-crusted fallow wheat field in Australia. When a power law is fitted to the u∗–Fair,d relation, i.e., Fair,d– u ∗ n , the coefficient of determination R2 is largest for n = 4. However, when a power law is fitted separately to data of each particle size range, n is found to depend on the particle size with values of 2.54 (0.7 μm), 3.40 (1.1 μm), 3.80 (1.7 μm), 4.32 (2.6 μm), 4.67 (4.6 μm), and 4.53 (7.0 μm), respectively, and maximum n was 4.67 for the 4.6 μm diameter. This suggests that the Fair,d– u ∗ n relationship is not universal, and embedded in n is the nature of soil aggregation. For practical purposes, n should be determined separately for each particle size range when estimating size-resolved dust fluxes.

Wind erosion of soils is a natural process that has shaped the semi-arid and arid landscapes for millennia. This paper describes the Dust Storm Index (DSI); a methodology for monitoring wind erosion using Australian Bureau of Meteorology (ABM) meteorological observational data since the mid-1960s (long-term), at continental scale. While the 46 year length of the DSI record is its greatest strength from a wind erosion monitoring perspective, there are a number of technical challenges to its use because when the World Meteorological Organisation (WMO) recording protocols were established the use of the data for wind erosion monitoring was never intended. Data recording and storage protocols are examined, including the effects of changes to the definition of how observers should interpret and record dust events. A method is described for selecting the 180 long-term ABM stations used in this study and the limitations of variable observation frequencies between stations are in part resolved. The rationale behind the DSI equation is explained and the examples of temporal and spatial data visualisation products presented include; a long term national wind erosion record (1965–2011), continental DSI maps, and maps of the erosion event types that are factored into the DSI equation. The DSI is tested against dust concentration data and found to provide an accurate representation of wind erosion activity. As the ABM observational records used here were collected according to WMO protocols, the DSI methodology could be used in all countries with WMO-compatible meteorological observation and recording systems.

Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks.

The dust storm on 22 and 23 September 2009, called “Red Dawn”, was the largest to pass over Sydney in term of reduced visibility (400 m) since reliable records began in 1940. The maximum hourly PM 10 concentration measured near Sydney was 15,366 μg/m 3 at Bringelly and is the highest ever recorded for Sydney and possibly any Australian capital city. The Australian air quality standard of 50 μg/m 3 per 24 h was massively exceeded at Randwick (1734 μg/m 3 ) and Newcastle (2426 μg/m 3 ). Red Dawn was caused by drought and the extreme wind conditions caused by a low pressure trough and cold front associated with a deep cut-off low pressure system. The source of the dust was the red sandplains of western New South Wales, the sandplains, riverine channels and lakes of the lower Lake Eyre Basin and Channel Country of Queensland. Between 22 September 2009 at 1400 and 23 September 2009, 0.3 Mt of PM 10 dust was transported off the coast between Albion Park and Newcastle (182 km length) near Sydney. The maximum hourly rate of PM 10 dust lost off the coast near Sydney was 71,015 t/h on 22 September at 2100. Calculating the total suspended particulate sediment lost off the Australian coast for the 3000 km long Red Dawn dust storm gives an estimate of 2.54 Mt for a plume height of 2500 m. This is the first and largest off-continent loss of soil ever reported using measured, as apposed to modelled, dust concentrations for Australia.

Environmental reporting and understanding of aeolian processes at different spatial and temporal scales require both extensive temporal and spatial data sources. The Bureau of Meteorology (BoM) SYNOP data have been used for environmental reporting in Australia by McTainsh and colleagues since 1998; however, with the current trend to replace meteorological observers with automated surface observation systems such as weather stations, these data sources are not sustainable. DustWatch was established to fill some of the gaps in the BoM network by strategically adding a community network of observers and instruments. Satellite imagery is also utilized when it is available. This paper outlines the nature of the DustWatch network, describes some of the educational and awareness outputs, outlines the types of data gathered and gives examples of how the data are being used both for environmental reporting and research into aeolian processes and activity. Copyright © 2008 John Wiley & Sons, Ltd.

Two sites on a playa (claypan) in south western Queensland, Australia were chosen to represent the variability in soil surface conditions known to control wind erosion and dust production in the region. The material was very fine and comprised of large amounts and different types of salts, high electrical conductivity, a propensity for slaking and the presence of cyanobacteria. The surfaces of 4 plots at each site were modified using in situ rainfall simulation and wind tunnel abrasion. The changes in the surface conditions were recorded using digital images and multi-angular spectral measurements of reflectance and inverted against a soil bi-directional spectral reflectance model. Optimised values of the model parameters produced the single scattering albedo (SSA) and a description of the scattering behaviour of the soil surfaces that included an estimate of microscopic roughness. The model parameters removed the effect of the measurement conditions (illumination and viewing geometry) on the spectral reflectance. Abrasion of the untreated surfaces demonstrated that the variability in the antecedent surface conditions played an important role in their response. Rainfall, drying and subsequent abrasion appeared to reset the soil surface conditions and controlled the spatial and temporal variation in the soil surface conditions. Redundancy analyses, conducted separately for SSA of selected wavebands, model parameter values and treatments elucidated the subtle and interactive effects of the treatments and surface responses. The results showed that high intensity rainfall and abrasion was associated with wavebands in the visible region and reduced roughness. Low intensity rainfall was associated with wavebands in the near-infrared and short-wave infrared regions and increased roughness. The analysis was interpreted as the result of eluviation due to rainsplash impact which caused size segregation and the preferential translocation of iron oxides to the surface and the creation of a thick surface seal and caused a thin crust which enabled the movement of salts and/or mineral clays to the surface because of the strong evaporation gradient. A poor relationship between aerodynamic resistance and microscopic roughness suggested that features of soil surface erodibility created by natural environmental processes such as rainsplash and wind erosion required a correction for macroscopic roughness. The values of the model parameters appeared to be insensitive to the directional nature of the abrasion process. The findings are significant for the development of this work towards an airborne or satellite-based assessment of soil surface erodibility and erosion.

Introduction We present what we believe to be the first case in the literature of rhabdomyolysis-induced renal failure caused by a probable drug interaction between elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF) and pravastatin/fenofibrate. Case presentation A 68-year old Caucasian man presented with progressive pain in both legs two weeks after commencing treatment with EVG/COBI/FTC/TDF. He was found to have biochemical evidence of rhabdomyolysis and acute renal failure. Conclusion We emphasize the need for post marketing surveillance of adverse effects of new products. Pharmacokinetic studies are necessary to investigate the levels of pravastatin in patients taking COBI and fenofibrate with and without other comorbidities. Meanwhile, we suggest that creatine kinase levels should be monitored and patients advised to report myalgias when using concomitant EVG/COBI/FTC/TDF and pravastatin/fenofibrate. This case serves as an important reminder to use estimated glomerular filtration rates rather than serum creatinine levels when choosing new medications. If potentially nephrotoxic combinations are started in patients with borderline estimated glomerular filtration rates, it may be prudent to check these filtration rates more frequently than usual. In patients with reduced estimated glomerular filtration rates, potentially nephrotoxic combinations should be avoided wherever possible.

Widespread drought and record maximum temperatures in eastern Australia produced a large dust storm on 23 October, 2002 which traversed a large proportion of eastern Australia and engulfed communities along a 2000 km stretch of coastline from south of Sydney (NSW) to north of Mackay (Queensland). This event provided an opportunity for a study of the impacts of rural dust upon the air quality of four Australian cities.

The dust storm of 23 October 2002 covered most of eastern Australia and carried one of the largest recorded dust loads in Australia. In the 6 months leading up to the event, severe drought conditions in eastern Australia, plus above average maximum temperatures resulted in high potential evapo-transpiration rates, producing severe soil moisture deficits and reduced vegetation cover. Although increased wind speeds associated with a fast moving cold front were the meteorological driving force, these winds speeds were lower than those for the previously documented large dust storms. The dust storm was 2400 km long, up to 400 km across and 1.5-2.5 km in height. The plume area was estimated at 840,860 km 2 and the dust load at 0900 h was 3.35-4.85 million tones (Mt). These dust load estimates are highly sensitive to assumptions, regarding visibility-dust concentration relationships, vertical dust concentration profiles and dust ceilings. The event is examined using meteorological records, remote sensing and air quality monitoring. (C) 2004 Elsevier Ltd. All rights reserved.

This paper describes a series of tests designed to evaluate the capacity of a personal computer (PC) based statistical curve-fitting program called MIX to quantify composite populations within multi-modal particle-size distributions. Three natural soil samples were analysed by a Coulter Multisizer, and their particle-size distributions analysed using MIX software to identify the modes, standard deviations and proportions of their composite populations. The particle-size distributions of the three natural soil samples were then numerically combined in equal proportions using a spreadsheet program to create synthetic particle-size distributions of known populations. MIX was then tested on the synthetic particle-size distributions to see if the modes and proportions it identified were similar to those modes and proportions known to characterize the synthetic particle-size distributions. The main outcome is that MIX can very accurately describe the modal particle size and proportions of the major composite populations within a particle-size distribution. However MIX has difficulty in identifying small populations (those contributing

A portable wind tunnel was used to test the contribution of biological and physical elements to overall soil aggregation on a soil dominated by biological soil crusts in south-eastern Australia. After moderate disturbance and simulated wind erosion, 90% of surface aggregates on the loamy soil and 76% on the sandy soil were dominated by biological elements (cryptogams). Lower levels of biological bonding were observed on the severely disturbed treatment. Linear regression indicated a significant positive relationship ( r 2 =0·72) between biological soil crust cover and dry aggregation levels greater than 0·85mm. To maintain sediment transport below an erosion control target of 5gm −1 s −1 for a 65kmh −1 wind at 10m height, a crust cover of approximately 20% is required. When a multiple regression model which sequentially fitted biological crust cover and dry aggregation greater than 0·85mm was applied to the data, dry aggregation accounted for more of the variation in sediment transport rate than biological crust cover. These data were used to develop a conceptual model which integrates crust cover and dry aggregation, and provides a useful framework within which to predict the likely impacts of changes in soil crust cover and aggregation.

The sampling frequency in space and time is often inadequate to estimate the accuracy and precision of aeolian sediment transport. The problem stems from a lack of knowledge about the spatial and temporal scale of variation in aeolian transport and is compounded by a shortage of resources (aeolian sediment traps and labour). This study developed a geostatistical methodology for estimating sediment transport at unsampled locations and tested the extent to which it was dependent on sampling networks (nested, grid and random) and frameworks (mobile or static sampling framework between wind erosion events). Aeolian transport data were collected in an area of Australia influenced by wind erosion (Diamantina Lakes National Park, southwestern Queensland) to evaluate the combination of events used for mapping transport. Insufficient wind erosion events occurred to test sediment sampling strategies and hence simulated sampling was conducted using maps of sediment transport produced with existing models of aeolian sediment transport in the same study area. Independent validation data were used to test the estimation performance. The results suggested that sampling networks that did not include information on the spatial scale of variation (i.e. grid and random sampling) did not represent adequately the sediment transport population. In contrast, a bespoke nested sampling network performed consistently better than the other networks. Overall the static framework with a nested network was recommended for estimation and mapping of sediment transport with few resources and was likely to be especially important for use over large areas. This approach has the advantage of requiring only a single pooled within-event variogram for sediment transport to be used to derive the model parameters for kriging or stochastic simulation for each event. Copyright © 2003 John Wiley & Sons, Ltd.

Little is known about the spatial and temporal scales of variation in aeolian processes. Studies that aim to investigate surface erodibility often sample aeolian sediment transport at the nodes of a regular grid of arbitrary size. Few aeolian transport investigations have the resources to obtain sufficient samples to produce reliable models for mapping the spatial variation of transport. This study reports the use of an innovative nested strategy for sampling multiple spatial scales simultaneously using 40 sediment samplers. Reliable models of the spatial variation in aeolian sediment transport were produced and used for ordinary punctual kriging and stochastic simulated annealing to produce maps for several wind erosion events over a 25 km 2 playa in western Queensland, Australia. The results support the existence of a highly dynamic wind erosion system that was responding to possibly cyclic variation in the availability of material and fluctuations in wind energy. The spatial scale of transport was considerably larger than the small scale expected of the factors controlling surface erodibility. Thus, it appears that transport cannot be used as a surrogate of erodibility at the scale of this investigation. Simulation maps of transport provided considerably more information than those from kriging about the variability in aeolian sediment transport and its possible controlling factors. The proposed optimal sampling strategy involves a nested approach using ca 50 samplers. Copyright  2003 John Wiley & Sons, Ltd.

Simulations of the global dust cycle and its interactions with a changing Earth system are hindered by the empirical nature of dust emission parameterizations in climate models. Here we take a step towards improving global dust cycle simulations by presenting a physically-based dust emission model. The resulting dust flux parameterization depends only on the wind friction speed and the soil's threshold friction speed, and can therefore be readily implemented into climate models. We show that our parameterization's functional form is supported by a compilation of quality-controlled vertical dust flux measurements, and that it better reproduces these measurements than existing parameterizations. Both our theory and measurements indicate that many climate models underestimate the dust flux's sensitivity to soil erodibility. This finding can explain why dust cycle simulations in many models are improved by using an empirical preferential sources function that shifts dust emissions towards the most erodible regions. In fact, implementing our parameterization in a climate model produces even better agreement against aerosol optical depth measurements than simulations that use such a source function. These results indicate that the need to use a source function is at least partially eliminated by the additional physics accounted for by our parameterization. Since soil erodibility is affected by climate changes, our results further suggest that many models have underestimated the climate sensitivity of the global dust cycle.

The pesticide endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide) has been detected in rivers in the cotton (Gossypium hirsutum L.)-growing area of northern New South Wales at a 5 yr mean (1991-1995) concentration of 0.06 mu g L-1. One pathway by which endosulfan reaches the riverine environment is transport on contaminated dust. Our objectives were to examine: (i) dust deposition from vehicular traffic on an unsealed road on a cotton farm, and around a cotton field in the 11 to 65 h period after endosulfan application; (ii) endosulfan deposition in the 11 to 65 h period after endosulfan application, and over a 3-mo period at on-farm and off-farm (nontarget) locations. Dust deposition rates from vehicular traffic varied from 0.013 g m(-2) vehicle(-1) at 1 m distance, to 0.002 g m(-2) vehicle(-1) at 100 m distance from an unsealed road (soil surface, no gravel added). The maximum endosulfan deposition in the 11 to 65 h post-spraying period was 95 mu g m(-2) at 5 m from the field. Over a 3-mo monitoring period (December 1996-March 1997), the average daily deposition rate of endosulfan was 0.16 mu g m(-2) d(-1) for the off-farm sites compared with 0.35 mu g m(-2) d(-1) for the on-farm site. As the measurement period was one of the wettest on record and the number of endosulfan applications was less-than-normal, the dust and endosulfan deposition results may be interpreted as minima.

A portable field wind tunnel was used to assess the sediment flux rates of loam and sand textured soils in the Mallee region of southeastern Australia. Three levels of crust disturbance (nil, moderate and severe) simulating stock trampling were investigated. The results demonstrated the importance of cryptogamic crusts in binding the soil surface and providing roughness after the soil was moderately disturbed. On the loamy soil, the crust helped maintain sediment flux rates below the erosion control target to 5 g m -1 s -1 for a 65 km h -1 wind measured at 10 m height. Once the crust was severely disturbed, sediment fluxes increased to 1·6 times the erosion target. On the sandy soil, even with no crust disturbance the sediment flux was 1·6 times the erosion control target. Disturbing the crust increased sediment fluxes to a maximum of 6·7 times the erosion control target. Removal of the crust also decreased the threshold wind velocity that resulted in an increase to the ris k of erosion from

Dust has been implicated as a pathway for endosulfan transport to the riverine environment in New South Wales. Anthropogenic dust, expressed as total suspended sediment (TSP), and particle associated endosulfan emissions were estimated on a cotton (Gossypium hirsutum L.) farm in northern New South Wales, Australia, using a combination of direct measurements and modelling. A vehicle travelling at 80 km h−1 on an unsealed road was a greater source of TSP emission (3.7 g m−1) than an 8-m wide inter-row cultivator travelling at 8 km h−1 (1.7 g m−1). However, the particle size distribution of the TSP from inter-row cultivation was finer (mode of 19–22 μm) than that from vehicular traffic on unsealed roads (mode of 32 μm) and hence may be transported further. Endosulfan source strength from inter-row cultivation was 3.6 μg m−1 of travel (or 0.45 μg m−2) which was only 6.0E-4% of that applied, 4 days after endosulfan application. This was slightly higher than the endosulfan source strength from vehicular traffic on an unsealed road (3.1 μg m−1 of travel), only 2 days after spraying. On unsealed roads, particle-associated endosulfan mass fractions declined rapidly with time due to volatilisation and photodegradation and a decrease in endosulfan-enriched source sediment due to the removal by repeated vehicle passes. For unsealed roads, TSP at 0.63 m height showed endosulfan-enrichment ratios of approximately four, compared to the surface soil 0–1 cm depth, for inter-row cultivation and vehicular traffic.

Grain-size characteristics and the flux of sediment transported by wind from a cultivated paddock in a Quaternary relict dune field are described. Sediments were collected at seven heights between 0.7 and 2.0 m. The distribution of sediment mass with height is explained by a power function (of the order of −1), which is highly skewed towards the bed. The distribution of