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Regional and nationwide geophysical merges consisting of magnetic and radiometric datasets have become standard practice within Australia and some parts of the world. The best practice for geophysical merges is to ensure the highest quality survey data is incorporated in all given areas. However, the traditional means of accomplishing this determination is quite qualitative without a well-defined methodology. Here, a quantitative algorithmic approach is provided, reducing user "guesswork" regarding which survey supersedes others when occupying the same space within geophysical merges. This is accomplished by assessing a wide range of survey specifications and applying weighted scores to their relative importance. This algorithm is applied to 889 datasets flown in New South Wales between 1957 and 2023 and provides a clear efficacy in determination of data quality based on survey design. Results from this algorithm have demonstrated proficiency in ranking surveys from highest to lowest quality and have formed the basis of all statewide geophysical merges in NSW since 2020. [ABSTRACT FROM AUTHOR]

The Wikki Warm Spring is one of the promising locations for the development of geothermal projects in Nigeria. Radiometric and remote sensing data were interpreted to enhance the understanding of the factors controlling the geothermal energy sources in the Wikki Warm Spring. Thus, mapping locations of concealed heat sources offer concentration areas for follow-up geothermal exploration. Landsat-8 imagery was used to produce the land surface temperature (LST) map, which reveals surface temperature variation that ranges from 50 to 95 °C. In comparison, the radiogenic heat map of the region generated from the radiometric data of the study area shows radiogenic heat production rate, which ranged from less than 0.69 to above 3.91 µWm−3. The radiogenic heat and LST maps show similar features, indicating that Basement Complex terrain exhibits high radiogenic and surface temperature than the Benue Trough. Monte Carlo simulation reveals statistical values that suggest that the most likely radiogenic heat value is 1.95 µWm−3 around the warm spring, the highest possible (best case scenario) heat value is 2.23 µWm−3, and the least possible value (worst case scenario) is 1.69 µWm−3. The Basement Complex terrain northwest of the warm spring produced high radiogenic heat, generating values above 3.91 μWm−3. The outcome of this investigation is very important for explorationists to institute sustainable geothermal energy mitigation plans and produce a clean and renewable energy in Wikki Warm Spring. [ABSTRACT FROM AUTHOR]

Earth observation aims at monitoring the Earth in increasingly more detail by improving the spatial, spectral and temporal resolution of image acquisitions. This can now be achieved in more cost-efficient ways by the miniaturization of instruments and platforms. New initiatives have emerged to accommodate hyperspectral instruments on CubeSats despite inherent platform limitations in terms of volume, power consumption, computing and downlink capacity. However, the adoption of CubeSat data for operational and scientific applications requires sufficient trust in dependability and data quality. Achieving reliable data quality from CubeSats remains challenging and requires advanced geometric, radiometric, and spectral calibration techniques. We present the successful in-orbit calibration of the HyperScout-1 mission. This In-Orbit Demonstration (IOD) mission, equipped with a miniaturized hyperspectral instrument based on Linear Variable Filter technology (LVF), was launched in 2018 by the European Space Agency (ESA). Rigorous inflight calibration has been applied to HyperScout-1 to ensure the accuracy of its data. The radiometric calibration of the HyperScout-1 instrument was performed vicariously based on modelled spectral radiances over a desert site. Independent validation using data from a CEOS RadCalNet site showed good radiometric accuracy with absolute radiometric errors <5%. Geometric errors due to inaccuracies in attitude measurements and sensor focal plane distortions were corrected using a bundle adjustment technique combined with matching to accurate Ground Control Points. This resulted in excellent geometric performance, with sub-pixel average absolute geolocation errors (~0.48 pixels across track and 0.51 pixels along track). The very limited data budget was a major challenge, forcing us to make some trade-offs in the calibration. Despite this, our robust vicarious calibration strategy allowed effective instrument calibration. As a result, the HyperScout-1 demonstrated the capability of an LVF Hyperspectral instrument on a CubeSat to deliver high-quality imagery and serve applications like land cover classification, change detection and disaster monitoring. [ABSTRACT FROM AUTHOR]

• Investigation of inter-satellite radiofrequency measurement-based autonomous orbit determination. • Range data type provides better state estimation than range-rate or line-of-sight angle data type. • The navigation system in the mesh topology provides better overall state estimation than the centralized topology. • Measurement biases and high measurement intervals reduce the overall system performance. Recent advances in space technology provide an opportunity for small satellites to be launched in cislunar space. However, tracking these small satellites still depends on ground-based operations. Autonomous navigation could be a possible solution considering the challenges presented by costly ground operations and limited onboard power available for small satellites. There have been various studies on autonomous navigation methods for cislunar missions. One of them, LiAISON, provides an autonomous orbit determination solution solely using inter-satellite measurements. This study aims at providing a detailed performance analysis of crosslink radiometric measurements based on autonomous orbit determination for cislunar small satellite formations considering the effects of measurement type, measurement accuracy, bias, formation geometry, and network topology. This study shows that range observations provide better state estimation performance than range-rate observations for the autonomous navigation system in cislunar space. Line-of-sight angle measurements derived from radiometric measurements do not improve the overall system performance. In addition, less precise crosslink measurement methods could be an option for formations in highly observable orbital configurations. It was found that measurement biases and measurements with high intervals reduce the overall system performance. In case there are more than two spacecraft in the formation, the navigation system in the mesh topology provides a better overall state estimation than the centralized topology. [ABSTRACT FROM AUTHOR]

In geological mapping, maps of K, Th, and U concentrations provided by airborne radiometric surveys are widely used to delineate geological units in tropical regions from the few rare outcrops. Indeed, thanks to their specific geochemical properties and behaviors, K, Th, and U allow us to trace geological processes. However, the combination of the concentrations of these radioelements does not allow us to determine the lithology in a unique way. We examined the potential of delineating the statistical parameters of K, Th, and U concentrations for geological mapping using the purpose airborne radiometric data in eastern Senegal. The mean, standard deviation, skewness, and kurtosis were calculated and mapped at a baseline of 3000 m. We noted the narrow dispersion of skewness and kurtosis values away from the expected curve for the log-normal distribution, implying that log-normal distributions dominate at the scale of analysis. The higher moments (kurtosis and skewness) varied more over shorter distances than lower order moments (mean and standard deviation). Mixtures of log-normal distributions across some lithological contacts with large differences in statistical parameters may account for this behavior. The area covered by the airborne radiometric data was classified into eight units according to the statistical parameters. The eight clusters do not show obvious correlations with geological units, but they may be interpreted in terms of the superposition of lithology and recent superficial processes (erosion and weathering). [ABSTRACT FROM AUTHOR]

In this paper, a rapid method for the determination of ash content of coal from the Oltenia quarry is presented. Ash is the main determining factor of coal quality. Natural coal contains carbon, mineral substances contained in the ash. Volatile content and moisture are in the same quantities, in geological structures and vary within insignificant intervals in terms of influence on the measurement result. Ash contains oxides of non-metals and metals in different conditions, but very little in its geological structure, so that radiometric measurements can be made accurately. This method of determining ash content is based on the interaction of gamma radiations with matter. [ABSTRACT FROM AUTHOR]

The presence of anthropogenic radioisotopes in the environment may be due to inappropriate discards, nuclear tests and accidents, which requires and justifies constant monitoring to ensure the safety of nuclear applications. The radiometric analysis is a necessary condition for exporting sugar for world consumption. The investigation of 134Cs and 137Cs in a sugar matrix is required to predict radiometric anomalies. This work aimed to standardise a semi-empirical radiometric model to characterise and quantify caesium isotopes in sugar. The research was carried out with high-resolution gamma spectrometry, a non-destructive method. The results were applied to the analysis of different types of sugar for export. The models allowed us to determine with excellent resolution the minimum quantifiable activities of 0.74 Bq kg−1 and 0.48 Bq kg−1 for 134Cs and 137Cs, respectively, which are lower than 600 Bq kg−1, reference values adopted by the EU for isotopes in food. [ABSTRACT FROM AUTHOR]

An estimate of the radiogenic heat production (RHP) across the different petrologic units of northeastern, Nigeria was previously not performed. Hence, their geothermal potentials are not widely known. However, an airborne radiometric data of equivalent uranium, (eU), equivalent thorium (eTh,) and percentage potassium (% K) acquired by Nigerian geological survey agency (NGSA) in the year 2009 was deployed in the evaluation of the RHP across the major petrologic outcrops of northeastern, Nigeria. The objective of this study is to estimate the quantity of RHP across the 13 petrologic units of the northeastern Nigerian terrain via the use of an empirical equation (RHP=ρ(0.0952Cu+0.0256CTh+0.0348Ck)). The petrologic units studied are; medium-coarse grained biotite-hornblende granites (OGe), porphyritic biotite-hornblende granites (OGp), banded gneiss (bG), charnokytes (Ch), ignimbrites (JYG), migmatites-gneiss (MG), basalts (bb), Gombe sandstones (GS), Pindiga Formation (PS), Yolde Formation (YL), Bima sandstones (BS), Keri-Keri Formation (KK), and alluvium (AL). Basic/preliminary processing such as; signal integration, signal validation, and examination of spurious data were applied prior to the RHP computation. The results of the heat production analysis performed show the range of RHP to be from 1.11μW/m3 to 3.35μW/m3 Hence, the maximum heat production value of 3.35μW/m3 was recorded along porphyritic biotite-hornblende granites (OGp) rock block, while the least value of 1.11μW/m3 was recorded over alluvium (AL) rock outcrops. Furthermore, the spatial distribution of the RHP values over the study location shows a gradual increase from the middle, low heat production (sedimentary zones) to the high heat producing areas (granitic and metamorphic zones) around eastern and western parts. The petrologic units arranged in order of decreasing magnitude of radiogenic heat generation are; OGp > MG > OGe/bG > bb > GS > Ch > JYG > BS > PS/YL > KK > AL. On a general note, the petrologic units studied were classified as low in terms of geothermal character based on comparison with other previous global RHP studies.

• Understanding the significance of emissivity at cryogenic temperature. • Overview of different methods for measuring emissivity, including calorimetric and radiometric techniques. • Detailed analysis of emissivity characteristics of metals, focusing on aluminum and stainless steel. In recent years, the development in measurement techniques of thermal radiative properties has attracted much attention to cryogenic applications, including space exploration, cryogenic research, medical applications, instrument design, planetary exploration and remote sensing, cryogenic storage and transportation. This paper discusses the importance of emissivity / absorptivity measurement, the factors they depend on, and the respective measurement methods, including calorimetric and radiometric. This paper also summarizes the published data on emissivity and absorptivity related to aluminum and stainless steel. It highlights the importance of surface treatment of materials, providing valuable insight into the significance of emissivity in cryogenic applications, which can serve as a reference for future research in this field. [ABSTRACT FROM AUTHOR]

In this study, it was examined whether the radiographic measurements taken from the tarsal region, especially the calcaneus, can be used in sex determination. In addition, two different horse breeds were used and whether these values would cause any difference between the breed was examined. 213 race horses were used in this study. Radiographic images of the left tarsal joint of Arabian horses (30 females, 57 males) and Thoroughbred horses (57 females, 69 males) were taken from the lateromedial direction. The widest point of the trochlea was seen to be a determinant in sex determination of Arabian horses. In Thoroughbred horses, it was seen that the value of the calcaneus body was the most important factor in sex determination. As a result of the discriminant analysis, 71.26% of male and female Arabian horses and 66.67% of Thoroughbred horses, respectively were classified correctly. It was observed that 88.26% of the horses between the two breeds were classified correctly regardless of sex. In the correlation test between measurements, negative correlation value with age was seen in the talus measurement (correlation value: -0.139-099). In conclusion, radiological measurements of this clinically important region can be used as an alternative method for sex and breed discrimination.

In geological mapping, maps of K, Th, and U concentrations provided by airborne radiometric surveys are widely used to delineate geological units in tropical regions from the few rare outcrops. Indeed, thanks to their specific geochemical properties and behaviors, K, Th, and U allow us to trace geological processes. However, the combination of the concentrations of these radioelements does not allow us to determine the lithology in a unique way. We examined the potential of delineating the statistical parameters of K, Th, and U concentrations for geological mapping using the purpose airborne radiometric data in eastern Senegal. The mean, standard deviation, skewness, and kurtosis were calculated and mapped at a baseline of 3000 m. We noted the narrow dispersion of skewness and kurtosis values away from the expected curve for the log-normal distribution, implying that log-normal distributions dominate at the scale of analysis. The higher moments (kurtosis and skewness) varied more over shorter distances than lower order moments (mean and standard deviation). Mixtures of log-normal distributions across some lithological contacts with large differences in statistical parameters may account for this behavior. The area covered by the airborne radiometric data was classified into eight units according to the statistical parameters. The eight clusters do not show obvious correlations with geological units, but they may be interpreted in terms of the superposition of lithology and recent superficial processes (erosion and weathering).

This study concerns the applied use of the natural radioactivity in soils. The relevance of airborne radiometric (gamma ray) survey data to peat mapping is now well established and such data have been used in a stand-alone sense and as covariates in machine learning algorithms. Here we present a method to use these data to accurately map the boundaries of peat (raised bogs). This has the potential to assist with the estimation of carbon stocks using a property-based assessment of soil. The significance of such regionally-uniform survey data lies in the subsurface information carried by the measurement which contrasts with the surficial nature of many other covariates. Soils attenuate radiometric flux by virtue of their bulk density (and associated carbon content) and water saturation level. The high attenuation levels in low density, wet peat materials give rise to a distinctive soil response. Here an entirely physics-based assessment of flux attenuation is carried out both theoretically and empirically. Radiometric data from the ongoing Tellus airborne survey of Ireland are used. The study area is characterised by an extensive assemblage of discrete raised peat bogs in a framework of largely mineral soils. Peat is detected by a property contrast with adjacent soils and so we consider all soils within the study area. The relatively low lateral resolution of the airborne data is demonstrated by modelling and we examine the behaviour of a combined spatial derivative of the data. The procedure allows the identification of the edges of the 128 peat polygons considered and indicates other additional potential areas of subsurface peat. The data appear to resolve the differences that exist across three available soil/peat databases that are used for the validation of the results obtained. [Display omitted] • 2D/3D modelling of airborne radiometric (gamma ray) flux over low density peat. • Detection of soil-peat contrasts demonstrated using spatial derivatives of flux. • Radiometric flux attenuation and edge-detection compared with existing soil mapping. • Results assessed using an extensive patchwork of raised bogs at individual and regional scales. [ABSTRACT FROM AUTHOR]

Soil samples from a mine site in Ijero, Ekiti State South-west Nigeria, were investigated for their elemental and radionuclides (40K, 232Th and 238U) concentrations to assess the contaminations levels. Twenty (20) soil samples were randomly collected using Dutch stainless steel Auger around the mine sites but largely dictated by the miners activities and locations. Elemental and radioactivity (40K, 232Th and 238U) components of the soils were determined using particle induced X-ray emission and Gamma spectrometers respectively. To assess the level of contamination and the possible anthropogenic impact, the pollution indices and the geo-accumulation indices of some elements were calculated. Twenty-six elemental (Na, Mg, Al, Si, Cl, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Rb, Zr, Nb, Cd, Sn, Ba, Nd, Bi, Pb, Pa, Th and U) concentrations were quantified. Average concentrations of these toxic elements; V (327 μg g-1), Cu (276 μg g-1), Nb (806 μg g-1), Cd (785 μg g-1), Pb (394 μg g-1), Th (473 μg g-1) and U (500 μg g-1) were particularly high, exceeding recommended values. Activity concentrations of the radionuclides ranged from 1 to 3, 4 to 10 and 415 to 15520 kBq kg-1 for 232Th, 238U, and 40K respectively with an average exceeding world limit which could lead to possible radiological consequences. Geo-accumulation and the pollution risk factor studies revealed that Pb could pose significant potential health risk to the miners and ecosystem.

In this study, it was examined whether the radiographic measurements taken from the tarsal region, especially the calcaneus, can be used in sex determination. In addition, two different horse breeds were used and whether these values would cause any difference between the breed was examined. 213 race horses were used in this study. Radiographic images of the left tarsal joint of Arabian horses (30 females, 57 males) and Thoroughbred horses (57 females, 69 males) were taken from the lateromedial direction. The widest point of the trochlea was seen to be a determinant in sex determination of Arabian horses. In Thoroughbred horses, it was seen that the value of the calcaneus body was the most important factor in sex determination. As a result of the discriminant analysis, 71.26% of male and female Arabian horses and 66.67% of Thoroughbred horses, respectively were classified correctly. It was observed that 88.26% of the horses between the two breeds were classified correctly regardless of sex. In the correlation test between measurements, negative correlation value with age was seen in the talus measurement (correlation value: -0.139-099). In conclusion, radiological measurements of this clinically important region can be used as an alternative method for sex and breed discrimination. [ABSTRACT FROM AUTHOR]

The Ozone Mapping and Profiler Suite (OMPS) Nadir Profilers (NPs) are advanced backscatter ultraviolet (BUV) hyperspectral instruments that measure ozone profiles in the Earth atmosphere. The first NP sensor onboard the Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite began its science observations on January 26, 2012, after its aperture door opened. The second OMPS NP, flying on the NOAA-20 satellite, opened its aperture door on January 8, 2018, starting science its data collection. The two NP sensors acquire Earth spectral images along their satellite flight path with a 16.7° wide swath, enabling weekly coverage of vertical ozone distribution in the Earth atmosphere. A successful thorough sensor calibration enables the NP sensors’ data records (SDRs) to meet measurement accuracy requirements. The largest error term in the albedo calibration came from the spectral wavelength calibration. This article provides SDRs accuracy analysis for both NP sensors and discusses important aspects of the SDRs performance in relation to the sensors’ characterization and calibration. [ABSTRACT FROM AUTHOR]

The study presents the results of the analyses of heat flow for geothermal energy exploration on a reconnaissance basis within the Bornu Basin and its environs using an airborne magnetic and radiometric data set. The study area is bounded with latitude 11.00–13.00°N and longitude 11.00–14.00°E with an estimated total area of 72,600 km2. The residual of the total magnetic field of the study area was subdivided into seventy-one (71) overlapping spectral blocks of 55 × 55 and 110 × 110 km2 windows. Spectral analysis by fast Fourier transform was performed on each overlapping block, and centroid depth and depth to the top of the magnetic source were obtained from the plots of the log of energy against wave number. The results showed that the centroid depth for the two windows ranges from 6.28 to 17.70 km and 7.83 km to 23.50 km, respectively. Similarly, the depth to the top of the magnetic source for the two windows also ranges from 1.66 to 6.12 km and 2.27 km to 6.37 km. The Curie point depth obtained for the two windows ranges from 8.78 to 32.69 km and 10 km to 42 km, respectively. The heat flow obtained using an average thermal conductivity of 2.54 Wm−1°C−1 ranges from 55.36 to 161.18 mWm−2 and 34.30 to 126 mWm−2 for the two windows, respectively. The maximum heat flow of 80 to 100 mWm−2 indicates that a geothermal potential source was found at the southeastern part of the study area corresponding to Gwoza and Galdekore. The results of radiogenic heat flow (RHP) range from 0.80 to 2.47 μWm−3. The maximum RHP of 2.2 to approximately 2.5 μWm−3 is considered as radiometric signatures signifying probable geothermal potential sources, which could be found at the southeastern part of the study area corresponding to Gwoza and Galdekore. The agreement between the two heat flows obtained from the analysis of airborne magnetic and radiometric data sets is an indicator that the southeastern part of the study area is a viable source for potential geothermal energy exploration. [ABSTRACT FROM AUTHOR]

Ultraviolet germicidal irradiation uses ultraviolet C (UV-C) energy to disinfect surfaces in clinical settings. Verifying that the doses of UV-C energy received by surfaces are adequate for proper disinfection levels can be difficult and expensive. Our study aimed to test commercially available colorimetric labels, sensitive to UV-C energy, and compare their precision with an accepted radiometric technique. The color-changing labels were found to predictably change color in a dose-dependent manner that would allow them to act as a qualitative alternative to radiometry when determining the minimum UV-C energy dosage received at surfaces. If deployed using careful protective techniques to avoid unintentional exposure to sunlight or other light sources, the use of colorimetric labels could provide inexpensive, easy, and accurate verification of effective UV-C dosing in clinical spaces. [ABSTRACT FROM AUTHOR]

Integrated geophysical techniques involving magnetic and radiometric data were used to investigate the subsurface geometry of Igarra schist belt in Precambrian basement complex of southwestern Nigeria which falls within the latitude range of 7° 1635.6” to 7° 1736.0’ North and longitude range of 6° 0534.1” to 6°05’44”East, with a view to interpret the geology of part of Igarra schist belt and estimate the depth to basement of magnetic source in the area. Six profiles were established with the objective of delineating the metasediments and its structural attributes, and geophysical measurements were made at 5m intervals along these profiles. The results of magnetic datasets were presented as maps and profiles of varying magnetic intensities and the causative rock types. Qualitative interpretation of the magnetic data using Reduction to pole, Analytical signal, first vertical, horizontal and tilt derivatives, upward continuation filters shows what has been interpreted as the signature of a near-vertical fault, trending along a NE-SW and NW-SE direction while radiometric datasets gave geochemical rates of U, Th and K as well as the effect of water contents on the rocks present within the study area. Qualitative and quantitative interpretation of individual magnetic anomalies and geological knowledge of the survey area yielded information on the depth of the geological features (e.g. rock contact, faults or fractures), structure and magnetic properties of rock units. 3D Euler deconvolution and Average radial spectrum were adopted to estimate the depth of the magnetic sources which ranges from - 92.895m to 73.95m; -115.45m to 57.44m and 63m to 44.1m; 88.2m to 81.9 m respectively. The Igarra schist belt has evolved different episodes of orogenies and the metasediments were formed from low grade regional metamorphism of argillaceous sediments such as shales or sediments of varying composition.

In this work, aeroradioactivity (airborne radiometric) data was used to characterize the lithology of Ijebu Ife, Southwest Nigeria. Measurements were made using Sodium Iodide [NaI (Tl)] detector mounted on a fixed-wing aircraft by Nigerian Geological Survey. Geochemical information on potassium (40K), thorium (232Th) and uranium (238U) concentrations were extracted from the raw data after correction and normalization due to contributions from soil, atmosphere, aircraft and cosmic radiation. The data was further subjected to photogeological analysis and image-enhancing techniques using minimum curvature gridding with cell size of 25 m after which single band, ratio and ternary images were generated and used to characterize the lithology of the area. Six lithologies including granite lithology, shale lithology, sandstone lithology, Lekki lagoon lithology, schist and clay lithologies were characterized after combining the single band, ratio and ternary maps. Results of radiometric analysis showed the relative abundances of each radioelement concentration within each lithologic unit. 232Th had 16.33 ± 0.62 ppm as the highest mean value of radioelement abundance within the granite lithology with the range of 2.93–62.42 ppm. 40K had the lowest mean concentration of 0.04 ± 0.00% within the Lekki lagoon lithology. These values reflected the overall average concentration and the nature of bedrock lithologies within their respective location of occurrence. This work showed the usefulness of aeroradioactivity data in the characterization of lithologies, environmental monitoring and assessment in terms of radiological distributions and radionuclide concentrations. [ABSTRACT FROM AUTHOR]

The workflow for estimating the temperature in agricultural fields from multiple sensors needs to be optimized upon testing each type of sensor’s actual user performance. In this sense, readily available miniaturized UAV-based thermal infrared (TIR) cameras can be combined with proximal sensors in measuring the surface temperature. Before the two types of cameras can be operationally used in the field, laboratory experiments are needed to fully understand their capabilities and all the influencing factors. We present the measurement results of laboratory experiments of UAV-borne WIRIS 2nd GEN and handheld FLIR E8-XT cameras. For these uncooled sensors, it took 30 to 60 min for the measured signal to stabilize and the sensor temperature drifted continuously. The drifting sensor temperature was strongly correlated to the measured signal. Specifically for WIRIS, the automated non-uniformity correction (NUC) contributed to extra uncertainty in measurements. Another problem was the temperature measurement dependency on various ambient environmental parameters. An increase in the measuring distance resulted in the underestimation of surface temperature, though the degree of change may also come from reflected radiation from neighboring objects, water vapor absorption, and the object size in the field of view (FOV). Wind and radiation tests suggested that these factors can contribute to the uncertainty of several Celsius degrees in measured results. Based on these indoor experiment results, we provide a list of suggestions on the potential practices for deriving accurate temperature data from radiometric miniaturized TIR cameras in actual field practices for (agro-)environmental research.

Airborne magnetic and radiometric datasets have, over the past few years, become powerful tools in the identification of porphyry systems which may host economic porphyry copper–gold–molybdenum ore bodies. Magnetisation contrasts with the unaltered host rocks, coupled with the elevated radiometric signature, compared to the host rock, makes identification of large-scale porphyry copper systems possible. Integrating these two different datasets with stream sediment data and other geochemical exploration methods results in a higher degree of confidence. Stream sediment data were analysed to see the distribution of copper and gold elements throughout the study area, located within the Eastern Papuan Peninsula of Papua New Guinea. Airborne geophysics data over the same area were also processed for magnetic and radiometric responses. The processing of the magnetic data revealed several magnetic anomalies related to concealed intrusive rock units, with associated radiometric signatures. The distribution of gold and copper anomalism was correlated with the geology and geophysical signatures. Results indicate varying degrees of correlation, with some areas showing a strong correlation between gold/copper occurrence and geophysical signatures, compared to other areas. Some factors that we believe impact the level of correlation may include tectonic history, volcanic cover, and weathering patterns. We recommend caution when applying multi-data exploration for porphyry copper systems.

This study describes the development of a prototype bi-spectral microbolometer sensor system designed explicitly for radiometric measurement and characterization of wildfire mid- and long-wave infrared radiances. The system is tested experimentally over moderate-scale experimental burns coincident with FLIR reference imagery. Statistical comparison of the fire radiative power (FRP; W) retrievals suggest that this novel system is highly reliable for use in collecting radiometric measurements of biomass burning. As such, this study provides clear experimental evidence that mid-wave infrared microbolometers are capable of collecting FRP measurements. Furthermore, given the low resource nature of this detector type, it presents a suitable option for monitoring wildfire behaviour from low resource platforms such as unmanned aerial vehicles (UAVs) or nanosats.

The results of simultaneous radar, radiometric, and lightning location measurements are analyzed to reveal interrelations between the characteristics of electric discharges and the parameters of a cumulonimbus cloud developing near Saint Petersburg. The dependences of the cloud electric activity on the radar characteristics as well as on the parameters derived from the Meteosat SEVIRI radiometer measurements are considered. It is found that lightning frequency highly correlates with the volume of supercooled cloud regions with high values of reflectivity. An increase in the lightning frequency occurs about 20 minutes after the moment when supercooled cloud volumes with reflectivity above 35–55 dBZ reach the maximum values. The maximum precipitation flux precedes the maximum lightning frequency. [ABSTRACT FROM AUTHOR]

The optimal installation angle of photovoltaic arrays was one of the effective means to make full use of solar power. The best installation angle was based on the sun altitude angle of the local summer solstice, and the effect of the local regional climatic conditions was less taken into account. The installation angle of photovoltaic array was optimized by data fitting method. Based on the astronomical basis, a formula for calculating the radiation of photovoltaic arrays was introduced by combining with the local periodic climatic characteristics. The experimental results show that the optimum azimuth angle of the distributed photovoltaic power station in Guilin university of technology is 11.3° and the best tilt angle is 27.5°. At this time the photovoltaic power generation is the highest. [ABSTRACT FROM AUTHOR]

Abstract Radiogenic heat production in Finland has been previously studied using airborne gamma-ray surveys and glacial till measurements alike. For the first time, this paper presents a detailed survey on the spatial variation in radiogenic heat production determined using outcrop samples obtained from all important lithologies of the country. The dataset of 6465 samples represents mostly Mesoarchean (about 2.7 Ga), Paleoproterozoic (ca. 2.2–1.8 Ga) and Mesoproterozoic (ca. 1.6–1.3 Ga) rocks. Nearly all data are from Precambrian Fennoscandian Shield area, but heat production appears to be highly variable, and above global Archean and Proterozoic averages. Spot readings show an arithmetic average of 1.34 ± 1.19 μWm−3, and a range from 0.02 to 19.4 μWm−3. The interpolated areal average of the whole area is 1.42 ± 1.41 μWm−3. The high standard deviation of data is related to the geochemical characteristics of uranium (U), thorium (Th) and potassium (K) resulting in a skewed distribution of heat production. Mesoproterozoic anorogenic rapakivi granites, and late Paleoproterozoic Svecofennian granitoids show the highest heat production values in the range of 3–5 μWm−3. The results show no distinct dependencies of heat production with geological age, metamorphic grade nor seismic P-wave velocity, but an increasing trend of heat production with SiO 2 content and decreasing trends of heat production with Fe 2 O 3 content and with rock density are evident. Surface heat flow (44 borehole data values) correlates weakly with heat production (r = 0.35). The general heterogeneity of heat production calls for supporting information from other geophysical methods for better understanding of the thermal state of the lithosphere in Finland and beyond. Graphical abstract Unlabelled Image Highlights • Radiogenic heat production was mapped using Finnish lithogeochemical data. • Data were available from 6465 rock outcrops, mostly from the Fennoscandian Shield. • Data were averaged spatially using regular grid and actual geological units. • Heat production appeared to be highly variable and largest in granitoid areas. • Heat production and heat flow have weak positive correlation. [ABSTRACT FROM AUTHOR]

The partial discharge (PD) leads to catastrophic failure of the medium voltage (MV) switchgear insulation. Determination of the PD source (defect) location in high voltage (HV) equipment is very important in the maintenance procedures and in isolating the root cause of PD generation. In this paper, the transient earth voltage (TEV) detection method was used to acquire defect-initiated PD signals in a simulated MV switchgear model. An array of four TEV sensors were placed on the surface walls outside an MV switchgear tank to acquire the PD signals generated from the known location(s)/coordinates of sharp needle type defect inside the tank. The time difference of arrival (TDOA) between signals that are captured by the TEV sensors array was critically analyzed. Estimating the TDOA between PD signals generated by PD source at a known location with high accuracy is of great importance for accurate defect localization. The cumulative energy method (CEM) is used to estimate the onset time point of each TEV signal. The estimated TDOA by the cumulative energy method is compared with actual and expected TDOA based on known coordinates of PD source and TEV sensors. Experimental data are used as a basis for determining the TEV method accuracy for PD source localization. Experimental results show the average error of time difference is about 1.34 ns, which is equivalent to the propagation distance of 0.4 m.

The airborne lidar system has been shown to be an effective and reliable method for spatial data collection. Lidar records the coordinates of point and intensity, dependent on range, incident angle, reflectivity of object, atmospheric condition, and several external factors. To fully utilize the intensity of a lidar system, several researchers have proposed correction models from lidar equations. The radiometric correction models are divided into physically-oriented models and data-oriented models. The lidar acquisition often contains multiple flight lines, and the radiation energy of each flight line can be calibrated independently by calibration coefficient. However, the calibrated radiances in the overlapped area have slightly different measurements. These parameters should be implicitly taken into account if calibrating radiances back to reflectance using known calibration targets. This study used a single-strip physically-oriented model to obtain a backscattering coefficient and a data-oriented model to obtain corrected intensity. We then selected homogeneous tie regions in the overlapped areas, and the differences between strips were compensated by gain and offset parameters in multi-strip radiometric block adjustment. The results were evaluated by the radiometric differences. Nine strips were acquired by Rigel Q680i system, and the experimental results showed that the delta intensity and delta backscattering coefficient of tie regions were improved up to 60% after multi-strip block adjustment.

The first two models of the Sea and Land Surface Temperature Radiometers (SLSTR) for the European Copernicus Sentinel-3 missions were tested prior to launch at the Rutherford Appleton Laboratory space instrument calibration facility. The pre-launch tests provide an essential reference that ensures that the flight data of SLSTR are calibrated to the same standards needed for surface temperature measurements and to those used by shipborne radiometers for Fiducial Reference Measurement (FRM). The radiometric calibrations of the thermal infrared channels were validated against accurate and traceable reference BB sources under flight representative thermal vacuum environment. Measurements were performed in both earth views for source temperatures covering the main operating range, for different instrument configurations and for the full field-of-view of the instruments. The data were used to derive non-linearity curves to be used in the level-1 processing. All results showed that the measured brightness temperatures and radiometric noise agreed within the requirements for the mission. An inconsistency that particularly affected SLSTR-A was observed which has been attributed to an internal stray light error. A correction for the stray light has been proposed to reduce the error. The internal stray light error was reduced for SLSTR-B by replacing the coating on the main aperture stop. We present a description of the test methodology and the key results.

One of the biggest changes in the world of optical remote sensing over the last several years is the sheer increase in the number of sensors that are imaging the Earth in moderate to high spatial resolution. With respect to the calibration of these sensors, they are broadly classified into two types, namely government systems and commercial systems. Because of the differences in the design and mission of these sensor types, calibration approaches are often substantially different. Thus, an opportunity exists to foster discussion between calibration teams for these sensors with the goal of improving overall sensor calibration and data interoperability. The approach used to accomplish this task was a one-day workshop where team members from both government and commercial sensors could share best practices, discuss methods for collaboration and improvement, and make recommendations for continuing activities. Five major recommendations were developed from the event that focused on coordinated activities using pseudo invariant calibration sites (PICS), broader and more consistent communication, collaboration on specific cross-calibration opportunities, developing a reference sensor for all optical systems, and encouraging the coordinated development of surface reflectance products. Workshop participants concluded that regular interactions between these teams could foster a better calibration of all sensor systems and accelerate the improved interoperability of surface products.

The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on 4 May 2002. The AIRS is designed to measure atmospheric temperature and water vapor profiles and has demonstrated exceptional radiometric and spectral accuracy and stability in orbit. The International System of Units (SI)-traceability of the derived radiances is achieved by transferring the calibration from the Large Area Blackbody (LABB) with SI traceable temperature sensors, to the On-Board Calibrator (OBC) blackbody during preflight testing. The AIRS views the OBC blackbody and four full aperture space views every scan. A recent analysis of pre-flight and on-board data has improved our understanding of the measurement uncertainty of the Version 5 AIRS L1B radiance product. For temperatures greater than 260 K, the measurement uncertainty is better than 250 mK 1-sigma for most channels. SI-traceability and quantification of the radiometric measurement uncertainty is critical to reducing biases in reanalysis products and radiative transfer models (RTMs) that use AIRS data, as well as establishing the suitability of AIRS as a benchmark for radiances established in the early 2000s.

In addition to precise 3D coordinates, most light detection and ranging (LIDAR) systems also record “intensity”, loosely defined as the strength of the backscattered echo for each measured point. To date, LIDAR intensity data have proven beneficial in a wide range of applications because they are related to surface parameters, such as reflectance. While numerous procedures have been introduced in the scientific literature, and even commercial software, to enhance the utility of intensity data through a variety of “normalization”, “correction”, or “calibration” techniques, the current situation is complicated by a lack of standardization, as well as confusing, inconsistent use of terminology. In this paper, we first provide an overview of basic principles of LIDAR intensity measurements and applications utilizing intensity information from terrestrial, airborne topographic, and airborne bathymetric LIDAR. Next, we review effective parameters on intensity measurements, basic theory, and current intensity processing methods. We define terminology adopted from the most commonly-used conventions based on a review of current literature. Finally, we identify topics in need of further research. Ultimately, the presented information helps lay the foundation for future standards and specifications for LIDAR radiometric calibration.

An onshore radiometric survey sampled in situ the isotopes U 238 , Th 232 , K 40 , and Rn 222 to build maps of normalized values for each element containing negative and positive radiometric anomalies, which could associate with hydrocarbon deposits in the subsoil. The vertical migration of hydrocarbon, water or other gases would have generated the different isotope anomalies. In four 2D seismic sections of the study area, three on dip direction and another in strike direction, we interpreted unconformities, flooding surface, and maximum flooding surfaces, as well as Cretaceous tops. In structural contour maps made from aforementioned seismic sections, we observe structural highs and structures such as truncations of strata. These structures in-depth coincide with uranium, thorium, potassium and radon anomalies seen on the surface. This oil and gas exploration approach that integrates radiometric and emanometric integrated with seismic prospecting can help to reduce the risk in hydrocarbons projects (however, radiometric anomalies are not uniquely associated with hydrocarbons). This work shows a correlation between radiometric (uranium, thorium, and potassium) and emanometric (radon) data in the surface with structures in the subsurface suck like truncation, that could present hydrocarbon, however, on this sub-basin, there has not been found commercial hydrocarbon. [ABSTRACT FROM AUTHOR]

The paper proposes spectral-brightness pyrometry (SBP) as a new approach to measure the temperature field dynamics on the emitting body surface. The brief review of modern methods of pyrometry – radiometric temperature measurements – is presented. Their properties are analyzed in the Wien’s approximation. The SBP combines the high resolution on temperature, time, and space typical for the brightness pyrometry instruments, and small methodical error of temperature measurements of materials with unknown emissivity intrinsic for spectral pyrometers. The peculiarity of this method is calibration of the brightness pyrometer – thermal vision camera – directly during the measurement process using the integral thermal radiation spectrum of the object. The mathematical model of the SBP measurement system is proposed, the technique of data processing based on this model is verified. The examples of practical implementation of the SBP method for the determination of temperature field dynamics of objects with unknown emissivity are presented. [ABSTRACT FROM AUTHOR]

The El Crispinejo granite forms part of a small, but distinctive late intrusive suite of cordierite-bearing peraluminous granites in the South Portuguese Zone (SPZ). This granite has the best outcrop relationships of the suite. It cross-cuts different members of the Sierra Norte Batholith of the SPZ and the Carboniferous Volcano-Sedimentary Complex of the Iberian Pyrite Belt, producing contact metamorphism. This late pluton has a high K content which results in a contrasting geophysical response (K-Th-U) with respect to the surrounding trondhjemitic granitoids of the TTG suite of the Sierra Norte Batholith. A concordant monazite-zircon U-Pb ID-TIMS age of 300.5 +0.5/-1.5Ma demonstrates Permo-Carboniferous age for this late Variscan magmatic event. The granite is associated with a series of ore showings (F-Pb-Zn and Sn-W) which are completely different from the nearby, massive sulphide and manganese ore deposits of the Iberian Pyrite Belt, indicating the unique character of this intrusion.

Hyperspectral images are of increasing importance in remote sensing applications. Imaging spectrometers provide semi-continuous spectra that can be used for physics based surface cover material identification and quantification. Preceding radiometric calibrations serve as a basis for the transformation of measured signals into physics based units such as radiance. Pushbroom sensors collect incident radiation by at least one detector array utilizing the photoelectric effect. Temporal variations of the detector characteristics that differ with foregoing radiometric calibration cause visually perceptible along-track stripes in the at-sensor radiance data that aggravate succeeding image-based analyses. Especially, variations of the thermally induced dark current dominate and have to be reduced. In this work, a new approach is presented that efficiently reduces dark current related stripe noise. It integrates an across-effect gradient minimization principle. The performance has been evaluated using artificially degraded whiskbroom (reference) and real pushbroom acquisitions from EO-1 Hyperion and AISA DUAL that are significantly covered by stripe noise. A set of quality indicators has been used for the accuracy assessment. They clearly show that the new approach outperforms a limited set of tested state-of-the-art approaches and achieves a very high accuracy related to ground-truth for selected tests. It may substitute recent algorithms in the Reduction of Miscalibration Effects (ROME) framework that is broadly used to reduce radiometric miscalibrations of pushbroom data takes.

Mamuju has been known to have high radiation dose rate which comes from NORM in rock and soil. Major concern is due to its location which is near inhabitant settlement area. Preliminary research has been done by environmental team which is limited to main access road only, while some remote area has left untouched. The purpose of the research is to delineate the location and distribution of thorium and uranium anomaly in Mamuju, and also to provide adequate information regarding the anomaly and high dose rate area to decision makers and stakeholders in neither local nor central government. Method applied is radiometric mapping using spectrometer RS-125 with NaI(Tl) detector in the area of interest Geological Formation of Adang Volcanic, which is more than 800 square km in size. The radiometric mapping method is widely used in uranium/thorium exploration, and now has been added with the measurement of radiation dose rate which is appropriate to environmental surveys. The mapping has been successfully delineated the area of NORM or the area with thorium and uranium anomaly. Thorium and uranium anomaly are related with multi-geological-process resulting the increase of grade into several fold from its original state