Comprehensive aerial survey quantifies high methane emissions from the New Mexico Permian Basin

Limiting emissions of climate-warming methane from oil and gas (O&G) is a major opportunity for short-term climate benefits. We deploy a basin-wide airborne survey of the New Mexico Permian Basin, spanning 35,923 km^2, 26,292 active wells, and over 15,000 km of natural gas pipelines using an independently-validated hyperspectral methane point source detection and quantification system. We estimate total O&G methane emissions in this area at 194 (+72/-68, 95% CI) metric tonnes per hour (t/h), or 9.4% (+3.5%/-3.3%) of gross gas production. 50% of observed emissions come from large emission sources with persistence-averaged emission rates over 308 kg/h. This result emphasizes the importance of capturing low-probability, high-consequence events through basin-wide surveys when estimating regional O&G methane emissions.

Prediction of peat depths using airborne radiometric data: optimization of ground surveys.

<p>The use of remote sensing data can lead to great efficiencies when mapping soil variables across broad regions. However, remote sensors rarely make direct measurements of the soil property of interest. Instead, an empirical model is required to relate the remote sensing data to ground measurements of the property of interest. We discuss how a survey of ground measurements required to calibrate such a model can be optimized. We make reference to the mapping of peat depth within the Dartmoor National Park (UK) using radiometric potassium data from an airborne survey of the region (http://www.tellusgb.ac.uk/). We expand the standard linear mixed model to accommodate nonlinear relationships between radiometric potassium and peat depths. The attenuation of the radiometric signal is seen to increase with peat depth, but the depth is particularly uncertain when the radiometric signal is small. When a spatial simulated annealing algorithm is used to optimize the locations for a survey of peat depth measurements to minimize the errors in the maps of peat depth upon use of the radiometric data, the complete range of the radiometric data are sampled but ground measurements are particularly focussed where the radiometric signal is small. We see that an optimized survey of 30 ground measurements combined with the radiometric data lead to more accurate maps than can be achieved from interpolation of more than 200 peat depth measurements.</p>

Sparse 3D seismic and magnetic imaging at Escondida porphyry copper mine, Chile

Seismic is often inferred to be synonymous with high cost. In a mineral environment, it is typically assumed to be viable only for mining operations or brownfield exploration. For greenfield exploration, other geophysical and geochemical/lithogeochemical methods are usually preferred, due in part to their affordability. We show results of a low-cost seismic survey over the Escondida porphyry copper deposit. The results show that low-cost 3D acquisition can improve structural understanding of established porphyry deposits and that there is potential for 3D seismic to be applied in brownfield and perhaps even greenfield exploration. The sparse 3D seismic reflection survey acquired at Escondida illuminates the structural setting and images stock genetically related to the Escondida intrusive complex at depth. The seismic results are compared to a magnetization vector inversion calculated from a regional airborne survey. This illustrates the potential for jointly utilizing the two methods to identify and prioritize anomalies for targeted drilling-based follow-up in exploration settings.

Impact of Arctic sea ice floe-scale anisotropy on airborne electromagnetic surveys

Airborne electromagnetic induction sensors have demonstrated their extensive capacities to measure sea-ice thickness distributions. However, biases can emerge when comparing these 1-D measurements to a broader 2-D regional scale due to the spatial anisotropy inherent to sea-ice cover. Automated processing of available sea-ice maps could significantly ease the decision on how to set up an optimised flight pattern, which would result in representative ice thickness numbers for the region. In this study, first we investigate the extent to which the sea-ice anisotropy can influence the representativeness of an airborne survey compared to the regional situation. Second, we propose a method to process sea-ice maps prior to flights to help preparing the most representative flight plan possible for the local area. The method is based on automated segmentation of radar satellite images and extensive simulation of flight transects over the image. The spatial analysis of these transects enables for the identification of the most representative survey trajectories for the area. The method was applied for seven different synthetic aperture radar satellite images over Arctic sea ice north of Svalbard. The results indicate that the proposed method improved the representativeness of the airborne survey by identifying the most suitable transect over the ice pack.

FIELD OPERATIONS AND PROGRESS OF CHINESE AIRBORNE SURVEY IN EAST ANTARCTICA THROUGH THE “SNOW EAGLE 601”

The Antarctic plays a vital role in the Earth system. However, our poor knowledge of the Antarctic limits predicting and projecting future climate changes and sea level rising due to rapid changing of the Antarctic. Airborne platforms can access most places of this hostile and remote continent and measure subice properties with high resolution and accuracy. China deployed the first fixed-wing airplane of “Snow Eagle 601” for Antarctic expeditions in 2015. Airborne scientific instruments, including radio-echo sounder, gravimeter, magnetometer, laser altimeter etc., were configured and integrated on the airplane. In the past four years, the airborne platform has been applied to survey the Princess Elizabeth Land, the largest data gap in Antarctica, Amery Ice Shelf and other critical areas in East Antarctica, and overall ∼150,000 km flight lines have been completed. Here, we introduced the “Snow Eagle 601” airborne platform and base stations, as well as field operations of airborne survey, including aviation supports, daily cycle of the scientific flight, data processing and quality control, and finally summarized progress of airborne survey in the past four years.

Low-Cost Unmanned Aerial Multispectral Imagery for Siltation Monitoring in Reservoirs

The recent and continuous development of unmanned aerial vehicles (UAV) and small cameras with different spectral resolutions and imaging systems promotes new remote sensing platforms that can supply ultra-high spatial and temporal resolution, filling the gap between ground-based surveys and orbital sensors. This work aimed to monitor siltation in two large rural and urban reservoirs by recording water color variations within a savanna biome in the central region of Brazil using a low cost and very light unmanned platform. Airborne surveys were conducted using a Parrot Sequoia camera (~0.15 kg) onboard a DJI Phantom 4 UAV (~1.4 kg) during dry and rainy seasons over inlet areas of both reservoirs. Field measurements of total suspended solids (TSS) and water clarity were made jointly with the airborne survey campaigns. Field hyperspectral radiometry data were also collected during two field surveys. Bio-optical models for TSS were tested for all spectral bands of the Sequoia camera. The near-infrared single band was found to perform the best (R2: 0.94; RMSE: 7.8 mg L−1) for a 0–180 mg L−1 TSS range and was used to produce time series of TSS concentration maps of the study areas. This flexible platform enabled monitoring of the increase of TSS concentration at a ~13 cm spatial resolution in urban and rural drainages in the rainy season. Aerial surveys allowed us to map TSS load fluctuations in a 1 week period during which no satellite images were available due to continuous cloud coverage in the rainy season. This work demonstrates that a low-cost configuration allows dense TSS monitoring at the inlet areas of reservoirs and thus enables mapping of the sources of sediment inputs, supporting the definition of mitigation plans to limit the siltation process.

Analysis of the Czech magnetic anomaly data obtained by ground-based and airborne magnetic surveys

<p>The modern epoch of ground magnetic surveying activity on the Czech territory was started by the Institute of Geophysics by setting up a fundamental network of the 1<sup>st</sup> order in 1957-58. It consists of 199 points and was reoccupied in 1976-78 and 1994-96. The anomaly maps were constructed by subtraction of the IGRF model.</p><p>Extensive aeromagnetic measurements have been performed from 1959 to 1972 by permalloy probe of Soviet provenience. The accuracy of the instrumentation was about (and often above) 10 nT. The second period of airborne survey started in 1976. Thanks to the deployment of proton precession magnetometer, the accuracy improved to ~ 2 nT. Since 2004 the measurements were carried out by caesium magnetometer. The data were digitized, known anthropogenic anomalies were cleared away and data were transformed to the regular grid with step 250 m. The final data file of magnetic anomalies ΔT, administered by the Czech Geological Survey, represents a substantial contribution to the exploration of ore deposits and to the structure geology in general.</p><p>In view of the fact that data file of magnetic anomalies was compiled from data acquired by heterogeneous methods in the course of more than 50 years, our recent study is aimed at looking into the homogeneity of the data by comparison them with ground-based magnetic survey. A simple comparison of the contour maps showed good similarity of the large regional anomalies. For more detailed analysis, the variation of ΔT in the neighbourhood of all points of the fundamental network was inspected and the basic statistic characteristics were computed. Summary results as well as several examples will be presented accordingly as the INSPIRE compliant services and eventually as the user-friendly web map application and made available on the CGS Portal http://mapy.geology.cz/ and on the updated web of the CzechGeo/EPOS consortium www.czechgeo.cz. Incorporating the map into the World Digital Magnetic Anomaly Map (WDMAM – IAGA) is also under consideration. This data will also be interesting for the EPOS.</p>

EnMAP airborne soil Greece campaign 2019

<p>In the frame of the science preparation activities for the upcoming German hyperspectral satellite mission EnMAP, an airborne survey took place in September 2019 with hyperspectral VNIR-SWIR-LWIR data using the HySpex sensor and the newly acquired Hyper-Cam LWIR camera from the GeoResearch Center Potsdam (GFZ) mounted on the airborne platform Cessna-T207A from the Free University Berlin (FUB). Although logistically complex conditions with several teams distributed in different locations, all the sites in central and northern Greece could be successfully acquired under clear sky conditions, and all data could be demilitarized providing 45 flight stripes covering a total area of 300 km<sup>2</sup>.</p><p>This abstract is focusing on the Amyntaio soil site in northern Greece, an agricultural area of variable soil composition from carbonate rich to clay/silt content to organic carbon rich fields around the lignite mine south of the area, over which 11 flight stripes could be acquired. The science goals of the Amyntaio soil campaign were: (a) Simulation of hyperspectral satellite imagery and demonstration of the potential of upcoming spaceborne hyperspectral sensors (EnMAP, CHIME) for global soil mapping and monitoring; (b) Large test and validation for existing soil algorithms such as the HYSOMA / ENSOMAP software tools for the prediction of top-soil quantitative surface properties; (c) Data validation and comparison of soil products with recent relevant satellite sensors (e.g. S2, PRISMA, ECOSTRESS); (d) Enlargement of global soil spectral libraries with harmonised standards and testbed for their use as calibration-validation data for soil spectral models.</p><p>Simultaneous to the airborne survey, an intensive ground-based campaign took place in the area focusing on the acquisition of soil data, VNIR-SWIR and LWIR in-situ data with field spectroradiometers (PSR+, ASD FieldSpec3, MEMS, Handheld FTIR), fractional vegetation cover with RGB and UAV RGB data, soil moisture, infiltrometer and spectral data in undisturbed soil crust with the SoilPRO device, and Cal-Val data acquisition at the same time than the overflight (Temperature-loggers, ASD VNIR-SWIR, handheld FTIR) over bare soils and black/white thermal targets.</p><p>We present the project objectives, selected field, airborne, satellite data, with preliminary analyses that show the high data quality and the potential of multi hyperspectral airborne campaigns as a support for basic science developments and satellite mission preparations. The results represent how more sensor flexibility can bridge the gap from in-situ to satellite scale. Further airborne flights and carefully designed in situ campaigns will allow testing and iterative improvement of new observational modalities for soil monitoring based on the integrated information from satellite platforms with the one provided by in-situ systems on the ground and air.</p>

Ophiolites mapping in the Taro Valley (Central Italy) by using an LWIR airborne TASI-600 survey: preliminary results on the Roccamurata complex

<p>In the framework of the INAL/BRIC research contract #ID57 (2016) different remote sensing technologies, from proximal to remote (from airborne to satellite), and processing classification technique have been exploited to detect both manmade materials containing asbestos and natural occurring asbestos (NOA) formations.</p><p>Asbestos minerals show characteristic spectral features in the LWIR spectral regions centered at about 9.6 µm. The VNIR-SWIR spectral region was well explored by multi and hyperspectral airborne, while the LWIR spectral range, at present, is still less explored for the detection and identification of the NOA. The LWIR range should have a high potential as asbestos minerals absorption feature are far from the ones of the other minerals commonly associated with them (e.g., carbonates).</p><p>The area surveyed by the multispectral LWIR airborne TASI-600 corresponds to a peridotitic ophiolite of great thickness and extension referring to the ophiolitic complex (i.e. including Roccamurata) along the banks of the Taro river [1], [3]. The ultramafic rock outcrops occurring in the Taro Valley (Italy), belong to the External Ligurid Units of the Northern Apennines within Cretaceous-Eocene sedimentary formation [2]. These ultramafic rocks formations include natural asbestos minerals that have a high potential hazard to human health if inhaled [3].</p><p>The airborne survey has been carried out using the airborne hyperspectral TASI-600 sensor acquiring 32 spectral bands in the 8.0 - 11.5 µm spectral range with a spectral resolution of 100 nm. The airborne survey was performed on a test area NW to the Borgo Val di Taro town along the Taro Valley for about 50 km2 at an altitude of about 1000 m a.s.l.. The survey covers two quarries of massive ophiolites (almost serpentine) on which samples have been collected in view of a further spectral and chemical analysis.</p><p>This communication will present the preliminary results of multispectral LWIR TASI survey performed on the Roccamurata study area in terms of: (i) radiometric and geometric correction; (ii) LST, by using a split window technique, and emissivity calculation by using a TES algorithm (iii) a preliminary result of the serpentine mapping compared with the available 2016 geological map (http://www.isprambiente.gov.it/Media/carg/note_illustrative/216_Borgo_Val_di_Taro.pdf).</p><ul><li>[1] Boschetti, T., & Toscani, L. (2008). Springs and streams of the Taro–Ceno Valleys (Northern Apennine, Italy): reaction path modeling of waters interacting with serpentinized ultramafic rocks. Chemical Geology, 257(1-2), 76-91.</li> <li>[2] Marroni, M., Molli, G., Montanini, A., Ottria, G., Pandolfi, L., & Tribuzio, R. (2002). The external Ligurian units (Northern Apennine, Italy); from rifting to convergence of a fossil ocean-continent transition zone. Ofioliti, 27(2), 119-131.</li> <li>[3] Gaggero, L., Crispini, L., Isola, E., & Marescotti, P. (2013). Asbestos in natural and anthropic ophiolitic environments: a case study of geohazards related to the Northern Apennine ophiolites (Eastern Liguria, Italy). Ofioliti, 38(1), 29-40.</li> <li>[4] Beghè, D., Dall’Asta, L., Garavelli, C., Pastorelli, A. A., Muscarella, M., Saccani, G., ... & Chetta, A. (2017). Sarcoidosis in an Italian province. Prevalence and environmental risk factors.PloS one,12(5), e0176859.</li> </ul>

ESA’s next-generation gravity mission concepts

The paper addresses the preparatory studies of future ESA mission concepts devoted to improve our understanding of the Earth’s mass change phenomena causing temporal variations in the gravity field, at different temporal and spatial scales, due to ice mass changes of ice sheets and glaciers, continental water cycles, ocean masses dynamics and solid Earth deformations. The ESA initiatives started in 2003 with a study on observation techniques for solid Earth missions and continued through several studies focusing on the satellite system, technology development for propulsion and distance metrology, preferred mission concepts, the attitude and orbit control system, as well as the optimization of the satellite constellation. These activities received precious inputs from the GOCE, GRACE and GRACE-FO missions. More recently, several studies related to new sensor concepts based on cold atom interferometry (CAI) were conducted, mainly focusing on technology development for different instrument configurations (GOCE-like and GRACE-like) and including validation activities, e.g. a first successful airborne survey with a CAI gravimeter. The latest results concerning the preferred satellite architectures and constellations, payload design and estimated science performance will be presented as well as remaining open issues for future concepts.