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Journal articles on the topic 'Water-borne geophysics'

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Author: Grafiati

Published: 10 December 2022

Last updated: 29 January 2023

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1

Barrett, Brian, Graham Heinson, Michael Hatch, and Andrew Telfer. "River sediment salt-load detection using a water-borne transient electromagnetic system." Journal of Applied Geophysics 58, no. 1 (August 2005): 29–44. http://dx.doi.org/10.1016/j.jappgeo.2005.03.002.

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2

Kusiluka, L. J. M., E. D. Karimuribo, R. H. Mdegela, E. J. Luoga, P. K. T. Munishi, M. R. S. Mlozi, and D. M. Kambarage. "Prevalence and impact of water-borne zoonotic pathogens in water, cattle and humans in selected villages in Dodoma Rural and Bagamoyo districts, Tanzania." Physics and Chemistry of the Earth, Parts A/B/C 30, no. 11-16 (January 2005): 818–25. http://dx.doi.org/10.1016/j.pce.2005.08.025.

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3

Rutishauser, Anja, Hansruedi Maurer, and Andreas Bauder. "Helicopter-borne ground-penetrating radar investigations on temperate alpine glaciers: A comparison of different systems and their abilities for bedrock mapping." GEOPHYSICS 81, no. 1 (January 1, 2016): WA119—WA129. http://dx.doi.org/10.1190/geo2015-0144.1.

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On the basis of a large data set, comprising approximately 1200 km of profile lines acquired with different helicopter-borne ground-penetrating radar (GPR) systems over temperate glaciers in the western Swiss Alps, we have analyzed the possibilities and limitations of using helicopter-borne GPR surveying to map the ice-bedrock interface. We have considered data from three different acquisition systems including (1) a low-frequency pulsed system hanging below the helicopter (BGR), (2) a stepped frequency system hanging below the helicopter (Radar Systemtechnik GmbH [RST]), and (3) a commercial system mounted directly on the helicopter skids (Geophysical Survey Systems Incorporated [GSSI]). The systems showed considerable differences in their performance. The best results were achieved with the BGR system. On average, the RST and GSSI systems yielded comparable results, but we observed significant site-specific differences. A comparison with ground-based GPR data found that the quality of helicopter-borne data is inferior, but the compelling advantages of airborne surveying still make helicopter-borne data acquisition an attractive option. Statistical analyses concerning the bedrock detectability revealed not only large differences between the different acquisition systems but also between different regions within our investigation area. The percentage of bedrock reflections identified (with respect to the overall profile length within a particular region) varied from 11.7% to 68.9%. Obvious factors for missing the bedrock reflections included large bedrock depths and steeply dipping bedrock interfaces, but we also observed that internal features within the ice body may obscure bedrock reflections. In particular, we identified a conspicuous “internal reflection band” in many profiles acquired with the GSSI system. We attribute this feature to abrupt changes of the water content within the ice, but more research is required for a better understanding of the nature of this internal reflection band.

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Foley, Neil, Slawek Tulaczyk, Esben Auken, Cyril Schamper, Hilary Dugan, Jill Mikucki, Ross Virginia, and Peter Doran. "Helicopter-borne transient electromagnetics in high-latitude environments: An application in the McMurdo Dry Valleys, Antarctica." GEOPHYSICS 81, no. 1 (January 1, 2016): WA87—WA99. http://dx.doi.org/10.1190/geo2015-0186.1.

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The McMurdo Dry Valleys are a polar desert in coastal Antarctica, where glaciers, permafrost, ice-covered lakes, and ephemeral summer streams coexist. Liquid water is found at the surface only in lakes and in the temporary streams that feed them. Past geophysical exploration has yielded ambiguous results regarding the presence of subsurface water. In 2011, we used a helicopter-borne, time-domain electromagnetic (TDEM) sensor to map resistivity in the subsurface across the Dry Valleys. The airborne electromagnetic (AEM) method excels at finding subsurface liquid water in polar deserts, where water remains liquid under cold conditions if it is sufficiently saline, and therefore electrically conductive. Over the course of 26 h of helicopter time, we covered large portions of the Dry Valleys and vastly increased our geophysical understanding of the subsurface, particularly with respect to water. Our data show extensive subsurface low-resistivity layers approximately 150–250 m below the surface and beneath higher resistivity layers. We interpret the low-resistivity layers as geologic materials containing freeze-concentrated or “cryoconcentrated” hyper saline brines lying beneath glaciers and frozen permafrost. These brines appeared to be contiguous with surface lakes, subglacial regions, and the Ross Sea, which could indicate a regional-hydrogeologic system, wherein solutes might be transported between surface reservoirs by ionic diffusion and subsurface flow. The presence of such brines underneath glaciers might have implications for glacier movement. Systems such as this, where brines exist beneath glacial ice and frozen permafrost, may exist elsewhere in coastal Antarctica; AEM resistivity is an ideal tool to find and survey them. Our application of TDEM demonstrates that in polar subsurface environments containing conductive brines, such a diffusive electromagnetic method is superior to radar surveying in terms of depth of penetration and ability to differentiate hydrogeologic conditions.

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5

Ikard, Scott J., Andrew P. Teeple, Jason D. Payne, Gregory P. Stanton, and J. Ryan Banta. "New Insights on Scale-dependent Surface-Groundwater Exchange from a Floating Self-potential Dipole." Journal of Environmental and Engineering Geophysics 23, no. 2 (June 2018): 261–87. http://dx.doi.org/10.2113/jeeg23.2.261.

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In south-central Texas the lower Guadalupe River has incised into the outcrop of the Carrizo-Wilcox aquifer. The river and the aquifer are hydraulically connected across the outcrop, although the connectivity is obscured at the surface by alluvium and surface-water and groundwater exchange dynamics are currently poorly understood. To investigate surface-water and groundwater exchange dynamics between the lower Guadalupe River and the Carrizo-Wilcox aquifer, a geophysical study was completed along a 14.86 km reach of the river by using water-borne gradient self-potential (SP) profiling and two-dimensional direct-current electric resistivity tomography. This paper explores the applicability of these water-borne geoelectric methods in delineating gaining and losing channel reaches, and demonstrates that geoelectric signals in the form of total electric field strength can be logged with an electric dipole and decomposed into component SP signals depicting regional and local groundwater flow patterns attributable to regional and localized hydraulic gradients. Localized SP anomalies of several tens of millivolts, indicative of hyporheic exchange flows, are observed and superimposed upon a 124 mV regional SP anomaly indicative of ambient groundwater exchange flows between the river and the aquifer. The observed SP signals are interpreted through two-dimensional finite-element modeling of streaming potentials attributable to ambient groundwater exchange and hyporheic exchange flow patterns. Variables of the channel environment such as temperature and concentration gradients, depth, and velocity are considered and subsequently eliminated as alternative sources of the SP signals that are presented.

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6

Hall, Amanda C., Guy J. P. Schumann, Jonathan L. Bamber, and Paul D. Bates. "Tracking water level changes of the Amazon Basin with space-borne remote sensing and integration with large scale hydrodynamic modelling: A review." Physics and Chemistry of the Earth, Parts A/B/C 36, no. 7-8 (January 2011): 223–31. http://dx.doi.org/10.1016/j.pce.2010.12.010.

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7

Bücker, Matthias, Adrián Flores Orozco, Jakob Gallistl, Matthias Steiner, Lukas Aigner, Johannes Hoppenbrock, Ruth Glebe, et al. "Integrated land and water-borne geophysical surveys shed light on the sudden drying of large karst lakes in southern Mexico." Solid Earth 12, no. 2 (February 24, 2021): 439–61. http://dx.doi.org/10.5194/se-12-439-2021.

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Abstract. Karst water resources play an important role in drinking water supply but are highly vulnerable to even slight changes in climate. Thus, solid and spatially dense geological information is needed to model the response of karst hydrological systems to such changes. Additionally, environmental information archived in lake sediments can be used to understand past climate effects on karst water systems. In the present study, we carry out a multi-methodological geophysical survey to investigate the geological situation and sedimentary infill of two karst lakes (Metzabok and Tzibaná) of the Lacandon Forest in Chiapas, southern Mexico. Both lakes present large seasonal lake-level fluctuations and experienced an unusually sudden and strong lake-level decline in the first half of 2019, leaving Lake Metzabok (maximum depth ∼25 m) completely dry and Lake Tzibaná (depth ∼70 m) with a water level decreased by approx. 15 m. Before this event, during a lake-level high stand in March 2018, we collected water-borne seismic data with a sub-bottom profiler (SBP) and transient electromagnetic (TEM) data with a newly developed floating single-loop configuration. In October 2019, after the sudden drainage event, we took advantage of this unique situation and carried out complementary measurements directly on the exposed lake floor of Lakes Metzabok and Tzibaná. During this second campaign, we collected time-domain induced polarization (TDIP) and seismic refraction tomography (SRT) data. By integrating the multi-methodological data set, we (1) identify 5–6 m thick, likely undisturbed sediment sequences on the bottom of both lakes, which are suitable for future paleoenvironmental drilling campaigns, (2) develop a comprehensive geological model implying a strong interconnectivity between surface water and karst aquifer, and (3) evaluate the potential of the applied geophysical approach for the reconnaissance of the geological situation of karst lakes. This methodological evaluation reveals that under the given circumstances, (i) SBP and TDIP phase images consistently resolve the thickness of the fine-grained lacustrine sediments covering the lake floor, (ii) TEM and TDIP resistivity images consistently detect the upper limit of the limestone bedrock and the geometry of fluvial deposits of a river delta, and (iii) TDIP and SRT images suggest the existence of a layer that separates the lacustrine sediments from the limestone bedrock and consists of collapse debris mixed with lacustrine sediments. Our results show that the combination of seismic methods, which are most widely used for lake-bottom reconnaissance, with resistivity-based methods such as TEM and TDIP can significantly improve the interpretation by resolving geological units or bedrock heterogeneities, which are not visible from seismic data. Only the use of complementary methods provides sufficient information to develop comprehensive geological models of such complex karst environments

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8

Sunilkumar, S. V., M. Muhsin, Maria Emmanuel, Geetha Ramkumar, K. Rajeev, and S. Sijikumar. "Balloon-borne cryogenic frost-point hygrometer observations of water vapour in the tropical upper troposphere and lower stratosphere over India: First results." Journal of Atmospheric and Solar-Terrestrial Physics 140 (March 2016): 86–93. http://dx.doi.org/10.1016/j.jastp.2016.02.014.

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9

Pruvost, P., J. Ovarlez, J. Lenoble, and W. P. Chu. "Comparison of Stratospheric Aerosol and Gas Experiment II and balloon-borne stratospheric water vapor measurements." Journal of Geophysical Research: Atmospheres 98, no. D3 (March 20, 1993): 4889–96. http://dx.doi.org/10.1029/92jd02337.

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10

Kent, Graham M., Isaac I. Kim, Alistair J. Harding, Robert S. Detrick, and John A. Orcutt. "Suppression of sea‐floor‐scattered energy using a dip‐moveout approach—Application to the mid‐ocean ridge environment." GEOPHYSICS 61, no. 3 (May 1996): 821–34. http://dx.doi.org/10.1190/1.1444007.

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Multichannel seismic (MCS) images are often contaminated with in‐ and out‐of‐plane scattering from the sea floor. This problem is especially acute in the mid‐ocean ridge environment where sea‐floor roughness is pronounced. Energy shed from the unsedimented basaltic sea floor can obscure primary reflections such as Moho, and scattering off of elongated sea‐floor features like abyssal hills and fault scarps can produce linear events in the seismic data that could be misinterpreted as subsurface reflections. Moreover, stacking at normal subsurface velocities may enhance these water‐borne events, whose stacking velocity depends on azimuth and generally increases with time, making them indistinguishable from subsurface arrivals. To suppress scattered energy in deep water settings, we propose a processing scheme that invokes the application of dip moveout (DMO) to deliberately increase the differential moveout between sea‐floor‐scattered and subsurface events, thereby facilitating the removal of unwanted energy in the stacked section. After application of DMO, all sea‐floor scatterers stack at the water velocity, while subsurface reflections like Moho still stack at their original velocity. The application of DMO in this manner is contrary to the intended use that reduces the differential moveout between dipping events and allows a single stacking velocity to be used. Unlike previous approaches to suppress scattered energy, dip filtering is applied in the common‐midpoint (CMP) domain after DMO. Moveover, our DMO‐based approach suppresses out‐of‐plane scattering, and therefore is not limited to removal of in‐plane scattering as is the case with shot and receiver dip filtering techniques. The success of our DMO‐based suppression scheme is limited to deep water (a few kilometers of water depth for conventional offsets), where the traveltime moveout of energy scattered from the sea floor has a hyperbolic moveout with a stacking velocity that depends on the cosine of the scatterer steering angle in a manner analogous to how the moveout of a dipping reflector depends on the dip angle. The application of DMO‐based suppression to synthetics and MCS data collected along the southern East Pacific Rise demonstrates the effectiveness of our approach. Cleaner images of primary reflectors such as Moho are produced, even though present shot coverage along the East Pacific Rise is unduly sparse, resulting in a limited effective spatial bandwidth.

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11

Melet, A., P. Teatini, G. Le Cozannet, C. Jamet, A. Conversi, J. Benveniste, and R. Almar. "Earth Observations for Monitoring Marine Coastal Hazards and Their Drivers." Surveys in Geophysics 41, no. 6 (June 5, 2020): 1489–534. http://dx.doi.org/10.1007/s10712-020-09594-5.

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Abstract Coastal zones have large social, economic and environmental values. They are more densely populated than the hinterland and concentrate large economic assets, critical infrastructures and human activities such as tourism, fisheries, navigation. Furthermore, coastal oceans are home to a wealth of living marine resources and very productive ecosystems. Yet, coastal zones are exposed to various natural and anthropogenic hazards. To reduce the risks associated with marine hazards, sustained coastal zone monitoring programs, forecasting and early warning systems are increasingly needed. Earth observations (EO), and in particular satellite remote sensing, provide invaluable information: satellite-borne sensors allow an effective monitoring of the quasi-global ocean, with synoptic views of large areas, good spatial and temporal resolution, and sustained time-series covering several years to decades. However, satellite observations do not always meet the precision required by users, in particular in dynamic coastal zones, characterized by shorter-scale variability. A variety of sensors are used to directly monitor the coastal zone and their observations can also be integrated into numerical models to provide a full 4D monitoring of the ocean and forecasts. Here, we review how EO, and more particularly satellite observations, can monitor coastal hazards and their drivers. These include coastal flooding, shoreline changes, maritime security, marine pollution, water quality, and marine ecology shifts on the one hand, and several physical characteristics (bathymetry, topography, vertical land motion) of coastal zones, meteorological and oceanic (metocean) variables that can act as forcing factors for coastal hazards on the other hand.

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12

Hoppenbrock, Johannes, Matthias Bücker, Jakob Gallistl, Adrián Flores Orozco, Carlos Pita de la Paz, César Emilio García García, José Alberto Razo Pérez, Johannes Buckel, and Liseth Pérez. "Evaluation of Lake Sediment Thickness from Water-Borne Electrical Resistivity Tomography Data." Sensors 21, no. 23 (December 2, 2021): 8053. http://dx.doi.org/10.3390/s21238053.

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Lakes are integrators of past climate and ecological change. This information is stored in the sediment record at the lake bottom, and to make it available for paleoclimate research, potential target sites with undisturbed and continuous sediment sequences need to be identified. Different geophysical methods are suitable to identify, explore, and characterize sediment layers prior to sediment core recovery. Due to the high resolution, reflection seismic methods have become standard for this purpose. However, seismic measurements cannot always provide a comprehensive image of lake-bottom sediments, e.g., due to lacking seismic contrasts between geological units or high attenuation of seismic waves. Here, we developed and tested a complementary method based on water-borne electrical-resistivity tomography (ERT) measurements. Our setup consisted of 13 floating electrodes (at 5 m spacing) used to collect ERT data with a dipole–dipole configuration. We used a 1D inversion to adjust a layered-earth model, which facilitates the implementation of constraints on water depth, water resistivity, and sediment resistivity as a priori information. The first two parameters were readily obtained from the echo-sounder and conductivity-probe measurements. The resistivity of sediment samples can also be determined in the laboratory. We applied this approach to process ERT data collected on a lake in southern Mexico. The direct comparison of ERT data with reflection seismic data collected with a sub-bottom profiler (SBP) showed that we can significantly improve the sediment-thickness estimates compared to unconstrained 2D inversions. Down to water depths of 20 m, our sediment thickness estimates were close to the sediment thickness derived from collocated SBP seismograms. Our approach represents an implementation of ERT measurements on lakes and complements the standard lake-bottom exploration by reflection seismic methods.

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13

Karaoulis, Marios, Ipo Ritsema, Chris Bremmer, Marco De Kleine, Gualbert Oude Essink, and Edvard Ahlrichs. "Drone-Borne Electromagnetic (DR-EM) Surveying in The Netherlands: Lab and Field Validation Results." Remote Sensing 14, no. 21 (October 25, 2022): 5335. http://dx.doi.org/10.3390/rs14215335.

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In the past decade, drones have become available and affordable for civil applications, including mapping and monitoring the Earth with geophysical sensors. In 2017 and 2019, the feasibility of executing frequency domain electromagnetic (FDEM) surveys using an off-the-shelf drone was investigated at Deltares Institute. This paper reports firstly the preparatory tests executed to determine the optimal instrumental configuration, flight path, data processing and inversion schemes and secondly the three field validation tests executed to demonstrate the feasibility of the drone-borne electromagnetic survey in real-scale applications. At several test sites, the optimal configuration of the drone and electromagnetic instruments, such as the mounting device and distance of the electromagnetic (EM) sensor with respect to the drone, the flight altitude, the coil separation and frequency of the EM source, efficiency and safety, and the assemblage of instrument and drone data were investigated. This has resulted in a robust method to acquire accurate and repeatable in-phase, quadrature and apparent resistivity data, and a workflow for data correction, processing and inversion scheme was developed. During those tests, three EM instruments were tested. The drone-borne electromagnetic (DR-EM) system has the ability and efficacy to fly over inaccessible areas and surface water. Compared to helicopter-borne electromagnetic surveys, the spatial resolution is much higher, which allows very detailed 3D mapping of subsurface targets, and the survey costs are relatively low. Repeated drone-borne electromagnetic (DR-EM) surveys allow low-cost monitoring of local changes in water saturation and salinity.

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14

Reid, J. E., A. Pfaffling, A. P. Worby, and J. R. Bishop. "In situ measurements of the direct-current conductivity of Antarctic Sea ice: implications for airborne electromagnetic Sounding of Sea-ice thickness." Annals of Glaciology 44 (2006): 217–23. http://dx.doi.org/10.3189/172756406781811772.

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AbstractAirborne, Ship-borne and Surface low-frequency electromagnetic (EM) methods have become widely applied to measure Sea-ice thickness. EM responses measured over Sea ice depend mainly on the Sea-water conductivity and on the height of the Sensor above the Sea-ice–sea-water interface, but may be Sensitive to the Sea-ice conductivity at high excitation frequencies. We have conducted in Situ measurements of direct-current conductivity of Sea ice using Standard geophysical geoelectrical methods. Sea-ice thickness estimated from the geoelectrical Sounding data was found to be consistently underestimated due to the pronounced vertical-to-horizontal conductivity anisotropy present in level Sea ice. At five Sites, it was possible to determine the approximate horizontal and vertical conductivities from the Sounding data. The average horizontal conductivity was found to be 0.017 Sm–1, and that in the vertical direction to be 9–12 times higher. EM measurements over level Sea ice are Sensitive only to the horizontal conductivity. Numerical modelling has Shown that the assumption of zero Sea-ice conductivity in interpretation of airborne EM data results in a negligible error in interpreted thickness for typical level Antarctic Sea ice.

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15

Siemon, Bernhard, Annika Steuer, Nico Deus, and Jörg Elbracht. "Comparison of manually and automatically derived fresh-saline groundwater boundaries from helicopter-borne EM data at the Jade Bay, Northern Germany." E3S Web of Conferences 54 (2018): 00032. http://dx.doi.org/10.1051/e3sconf/20185400032.

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The Federal Institute for Geosciences and Natural Resources (BGR) conducted many airborne geophysical surveys in Northern Germany during the last decades. The coastal regions of Lower Saxony were investigated by frequency-domain helicopter-borne electromagnetics (HEM) to reveal the bulk resistivity of the subsurface (sediments and pore fluids). The State Authority for Mining, Energy and Geology (LBEG) is preparing a statewide “saltwater map” for Lower Saxony with a focus on the coastal aquifers influenced by seawater intrusion. For this purpose, the HEM resistivities are used in combination with groundwater data and a geological model to derive the lower fresh-water boundary. As appropriate depth values are manually picked from vertical resistivity sections, this procedure is time consuming. Therefore, we tested an alternative, which automatically derives the fresh-saline groundwater boundary directly from the HEM resistivity models. The ambiguity between brackish/saline water and clayey sediments as source for low resistivities can somewhat be reduced by the application of gradients instead of threshold values for searching an appropriate boundary. We compare results of both methods using a dataset from a coastal region at the Jade Bay.

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16

Dierking, Wolfgang, Oliver Lang, and Thomas Busche. "Sea ice local surface topography from single-pass satellite InSAR measurements: a feasibility study." Cryosphere 11, no. 4 (August 29, 2017): 1967–85. http://dx.doi.org/10.5194/tc-11-1967-2017.

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Abstract. Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere–ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR) for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that, theoretically, surface height variations can be retrieved with relative errors ≤ 0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.

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17

Sulzbacher, H., H. Wiederhold, B. Siemon, M. Grinat, J. Igel, T. Burschil, T. Günther, and K. Hinsby. "Numerical modelling of climate change impacts on freshwater lenses on the North Sea Island of Borkum using hydrological and geophysical methods." Hydrology and Earth System Sciences 16, no. 10 (October 16, 2012): 3621–43. http://dx.doi.org/10.5194/hess-16-3621-2012.

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Abstract. A numerical, density dependent groundwater model is set up for the North Sea Island of Borkum to estimate climate change impacts on coastal aquifers and especially the situation of barrier islands in the Wadden Sea. The database includes information from boreholes, a seismic survey, a helicopter-borne electromagnetic (HEM) survey, monitoring of the freshwater-saltwater boundary by vertical electrode chains in two boreholes, measurements of groundwater table, pumping and slug tests, as well as water samples. Based on a statistical analysis of borehole columns, seismic sections and HEM, a hydrogeological model is set up. The groundwater model is developed using the finite-element programme FEFLOW. The density dependent groundwater model is calibrated on the basis of hydraulic, hydrological and geophysical data, in particular spatial HEM and local monitoring data. Verification runs with the calibrated model show good agreement between measured and computed hydraulic heads. A good agreement is also obtained between measured and computed density or total dissolved solids data for both the entire freshwater lens on a large scale and in the area of the well fields on a small scale. For simulating future changes in this coastal groundwater system until the end of the current century, we use the climate scenario A2, specified by the Intergovernmental Panel on Climate Change and, in particular, the data for the German North Sea coast. Simulation runs show proceeding salinisation with time beneath the well fields of the two waterworks Waterdelle and Ostland. The modelling study shows that the spreading of well fields is an appropriate protection measure against excessive salinisation of the water supply until the end of the current century.

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18

Sulzbacher, H., H. Wiederhold, B. Siemon, M. Grinat, J. Igel, T. Burschil, T. Günther, and K. Hinsby. "Numerical modelling of climate change impacts on freshwater lenses on the North Sea Island of Borkum." Hydrology and Earth System Sciences Discussions 9, no. 3 (March 15, 2012): 3473–525. http://dx.doi.org/10.5194/hessd-9-3473-2012.

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Abstract. A numerical variable-density groundwater model is set up for the North Sea Island of Borkum to estimate climate change impacts on coastal aquifers and especially the situation of barrier islands in the Wadden Sea. The database includes information from boreholes, a seismic survey, a helicopter-borne electromagnetic survey (HEM), monitoring of the freshwater-saltwater boundary by vertical electrode chains in two boreholes, measurements of groundwater table, pumping and slug tests, as well as water samples. Based on a statistical analysis of borehole columns, seismic sections and HEM, a hydrogeological model is set up. The groundwater model is developed using the finite-element programme FEFLOW. The variable-density groundwater model is calibrated on the basis of hydraulic, hydrological and geophysical data, in particular spatial HEM and local monitoring data. Verification runs with the calibrated model show good agreement between measured and computed hydraulic heads. A good agreement is also obtained between measured and computed density or total dissolved solids data for both the entire freshwater lens on a large scale and in the area of the well fields on a small scale. For simulating future changes in this coastal groundwater system until the end of the current century we use the climate scenario A2, specified by the Intergovernmental Panel on Climate Change and in particular the data for the German North Sea coast. Simulation runs show proceeding salinization with time beneath the well fields of the two waterworks Waterdelle and Ostland. The modelling study shows that spreading of well fields is an appropriate protection measure against excessive salinization of the water supply until the end of the current century.

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19

Delene, David J., Terry Deshler, Perry Wechsler, and Gabor A. Vali. "A balloon-borne cloud condensation nuclei counter." Journal of Geophysical Research: Atmospheres 103, no. D8 (April 1, 1998): 8927–34. http://dx.doi.org/10.1029/98jd00053.

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20

Sen, B., G. C. Toon, J. F. Blavier, E. L. Fleming, and C. H. Jackman. "Balloon-borne observations of midlatitude fluorine abundance." Journal of Geophysical Research: Atmospheres 101, no. D4 (April 1, 1996): 9045–54. http://dx.doi.org/10.1029/96jd00227.

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21

Merlaud, Alexis, Frederik Tack, Daniel Constantin, Lucian Georgescu, Jeroen Maes, Caroline Fayt, Florin Mingireanu, et al. "The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) and its operations from an unmanned aerial vehicle (UAV) during the AROMAT campaign." Atmospheric Measurement Techniques 11, no. 1 (January 29, 2018): 551–67. http://dx.doi.org/10.5194/amt-11-551-2018.

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Abstract. The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) is a compact remote sensing instrument dedicated to mapping trace gases from an unmanned aerial vehicle (UAV). SWING is based on a compact visible spectrometer and a scanning mirror to collect scattered sunlight. Its weight, size, and power consumption are respectively 920 g, 27 cm × 12 cm × 8 cm, and 6 W. SWING was developed in parallel with a 2.5 m flying-wing UAV. This unmanned aircraft is electrically powered, has a typical airspeed of 100 km h−1, and can operate at a maximum altitude of 3 km. We present SWING-UAV experiments performed in Romania on 11 September 2014 during the Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign, which was dedicated to test newly developed instruments in the context of air quality satellite validation. The UAV was operated up to 700 m above ground, in the vicinity of the large power plant of Turceni (44.67∘ N, 23.41∘ E; 116 ma.s.l.). These SWING-UAV flights were coincident with another airborne experiment using the Airborne imaging differential optical absorption spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP), and with ground-based DOAS, lidar, and balloon-borne in situ observations. The spectra recorded during the SWING-UAV flights are analysed with the DOAS technique. This analysis reveals NO2 differential slant column densities (DSCDs) up to 13±0.6×1016 molec cm−2. These NO2 DSCDs are converted to vertical column densities (VCDs) by estimating air mass factors. The resulting NO2 VCDs are up to 4.7±0.4×1016 molec cm−2. The water vapour DSCD measurements, up to 8±0.15×1022 molec cm−2, are used to estimate a volume mixing ratio of water vapour in the boundary layer of 0.013±0.002 mol mol−1. These geophysical quantities are validated with the coincident measurements.

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22

López-Moreno, J. J., R. Rodrigo, and S. Vidal. "Radiative contamination in rocket-borne infrared photometric measurements." Journal of Geophysical Research 90, A7 (1985): 6617. http://dx.doi.org/10.1029/ja090ia07p06617.

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23

Heaps, William S., and Thomas J. McGee. "Progress in stratospheric hydroxyl measurement by balloon-borne LIDAR." Journal of Geophysical Research: Atmospheres 90, no. D5 (August 20, 1985): 7913–21. http://dx.doi.org/10.1029/jd090id05p07913.

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24

Milani, L., F. Porcù, D. Casella, S. Dietrich, G. Panegrossi, M. Petracca, and P. Sanò. "Analysis of long-term precipitation pattern over Antarctica derived from satellite-borne radar." Cryosphere Discussions 9, no. 1 (January 8, 2015): 141–82. http://dx.doi.org/10.5194/tcd-9-141-2015.

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Abstract:

Abstract. Mass accumulation is a key geophysical parameter in understanding the Antarctic climate and its role in the global system. The local mass variation is driven by a number of different mechanisms: the deposition of snow and ice crystals on the surface from the atmosphere is generally modified by strong surface winds and variations in temperature and humidity at the ground, making it difficult to measure directly the accumulation by a sparse network of ground based instruments. Moreover, the low cloud total water/ice content and the varying radiative properties of the ground pose problems in the retrieval of precipitation from passive space-borne sensors at all frequencies. Finally, numerical models, despite their high spatial and temporal resolution, show discordant results and are difficult to be validated using ground-based measurements. A significant improvement in the knowledge of the atmospheric contribution to the mass balance over Antarctica is possible by using active space-borne instruments, such as the Cloud Profiling Radar (CPR) on board the low earth orbit CloudSat satellite, launched in 2006 and still operating. The radar measures the vertical profile of reflectivity at 94 GHz (sensitive to small ice particles) providing narrow vertical cross-sections of clouds along the satellite track. The aim of this work is to show that, after accounting for the characteristics of precipitation and the effect of surface on reflectivity in Antarctica, the CPR can retrieve snowfall rates on a single event temporal scale. Furthermore, the CPR, despite its limited temporal and spatial sampling capabilities, also effectively observes the annual snowfall cycle in this region. Two years of CloudSat data over Antarctica are analyzed and converted in water equivalent snowfall rate. Two different approaches for precipitation estimates are considered in this work. The results are analyzed in terms of annual and monthly averages, as well as in terms of instantaneous values. The derived snowfall maps are compared with ERA-Interim reanalysis and with in situ measurements, showing overall agreement. The effects of coastlines in enhancing precipitation rates and cloud precipitation efficiency are recognized. A significant seasonal signal also affects the averaged spatial extent of snowfall patterns. A comparison with snow accumulation ground measurements of single snowfall events shows consistency with the CPR retrievals: all the retrieved snowfall episodes correspond to an increase of snow accumulation at the ground, while several episodes of increase of snow stack height are not related to significant retrieved snowfall rate, likely indicating the local contribution of blowing snow. The results show that CPR can be a valuable source of snowfall rate data in Antarctica that can be used at different temporal scales, providing support to the sparse network of ground-based instruments both for numerical model validation and climatological studies.

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25

Rosen, James M., and Norman T. Kjome. "Balloon-borne measurements of the aerosol extinction-to-backscatter ratio." Journal of Geophysical Research: Atmospheres 102, no. D10 (May 1, 1997): 11165–69. http://dx.doi.org/10.1029/97jd00363.

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26

Few, A. A., and A. J. Weinheimer. "Factor of 2 error in balloon-borne atmospheric conduction current measurements." Journal of Geophysical Research 91, no. D10 (1986): 10937. http://dx.doi.org/10.1029/jd091id10p10937.

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27

Massie, S. T., J. A. Davidson, C. A. Cantrell, A. H. McDaniel, J. C. Gille, V. G. Kunde, J. C. Brasunas, et al. "Atmospheric infrared emission of ClONO2observed by a balloon-borne Fourier spectrometer." Journal of Geophysical Research 92, no. D12 (1987): 14806. http://dx.doi.org/10.1029/jd092id12p14806.

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28

Beig, G., J. S. Sidhu, S. R. Das, and D. K. Chakrabarty. "Balloon-borne measurements of the stratospheric ion conductivity profile at low latitude." Journal of Geophysical Research 94, no. D8 (1989): 11070. http://dx.doi.org/10.1029/jd094id08p11070.

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29

Li, Ya Qi, Robert H. Holzworth, Hua Hu, Michael McCarthy, R. Dayle Massey, Paul M. Kintner, Juan V. Rodrigues, Umran S. Inan, and W. C. Armstrong. "Anomalous optical events detected by rocket-borne sensor in the WIPP Campaign." Journal of Geophysical Research: Space Physics 96, A2 (February 1, 1991): 1315–26. http://dx.doi.org/10.1029/90ja01727.

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30

Ramachandran, S., A. Jayaraman, Y. B. Acharya, and B. H. Subbaraya. "Balloon-borne photometric studies of the stratospheric aerosol layer after Mt. Pinatubo eruption." Journal of Geophysical Research 99, no. D8 (1994): 16771. http://dx.doi.org/10.1029/94jd00966.

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31

Eastes, Richard W., and William E. Sharp. "Rocket-borne spectroscopic measurements in the ultraviolet aurora: The Lyman-Birge-Hopfield bands." Journal of Geophysical Research 92, A9 (1987): 10095. http://dx.doi.org/10.1029/ja092ia09p10095.

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32

Ogura, Koichi, and Masahiro Kodama. "Ghost images of auroral X ray sources observed by directional balloon-borne detectors." Journal of Geophysical Research 94, A2 (1989): 1508. http://dx.doi.org/10.1029/ja094ia02p01508.

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33

Goldman, A., F. J. Murcray, D. G. Murcray, J. J. Kosters, C. P. Rinsland, J. M. Flaud, C. Camy-Peyret, and A. Barbe. "Isotopic abundances of stratopheric ozone from balloon-borne high-resolution infrared solar spectra." Journal of Geophysical Research: Atmospheres 94, no. D6 (June 20, 1989): 8467–73. http://dx.doi.org/10.1029/jd094id06p08467.

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34

Orsolini, Yvan J., Gloria L. Manney, Andreas Engel, Joelle Ovarlez, Chantal Claud, and Larry Coy. "Layering in stratospheric profiles of long-lived trace species: Balloon-borne observations and modeling." Journal of Geophysical Research: Atmospheres 103, no. D5 (March 1, 1998): 5815–25. http://dx.doi.org/10.1029/97jd03131.

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35

Jonsson, Haflidi H. "Possible sources of errors in electrical measurements made in thunderclouds with balloon-borne instrumentation." Journal of Geophysical Research 95, no. D13 (1990): 22539. http://dx.doi.org/10.1029/jd095id13p22539.

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36

Rawlins, W. T., A. M. Woodward, and D. R. Smith. "Aeronomy of infrared ozone fluorescence measured during an aurora by the SPIRIT 1 rocket-borne interferometer." Journal of Geophysical Research: Space Physics 98, A3 (March 1, 1993): 3677–91. http://dx.doi.org/10.1029/92ja02607.

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37

Kochel, Jeanne-Marie, Jean-Michel Hartmann, Claude Camy-Peyret, Rodolphe Rodrigues, and Sébastien Payan. "Influence of line mixing on absorption by CO2Q branches in atmospheric balloon-borne spectra near 13 μm." Journal of Geophysical Research: Atmospheres 102, no. D11 (June 1, 1997): 12891–99. http://dx.doi.org/10.1029/97jd00405.

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38

Goldman, A., F. J. Murcray, R. D. Blatherwick, J. J. Kosters, F. H. Murcray, D. G. Murcray, and C. P. Rinsland. "New spectral features of stratospheric trace gases identified from high-resolution infrared balloon-borne and laboratory spectra." Journal of Geophysical Research: Atmospheres 94, no. D12 (October 20, 1989): 14945–55. http://dx.doi.org/10.1029/jd094id12p14945.

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39

Dowd, Michael, and Keith R. Thompson. "Extraction of tidal streams from a ship-borne acoustic Doppler current profiler using a statistical-dynamical model." Journal of Geophysical Research: Oceans 101, no. C4 (April 15, 1996): 8943–56. http://dx.doi.org/10.1029/95jc02693.

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40

Patra, A. K., N. Venkateswara Rao, D. V. Phanikumar, H. Chandra, U. Das, H. S. S. Sinha, T. K. Pant, and S. Sripathi. "A study on the low-latitude daytimeEregion plasma irregularities using coordinated VHF radar, rocket-borne, and ionosonde observations." Journal of Geophysical Research: Space Physics 114, A11 (November 2009): n/a. http://dx.doi.org/10.1029/2009ja014501.

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41

Reiner, Thomas, Markus Hanke, Frank Arnold, Helmut Ziereis, Hans Schlager, and Wolfgang Junkermann. "Aircraft-borne measurements of peroxy radicals by chemical conversion/ion molecule reaction mass spectrometry: Calibration, diagnostics, and results." Journal of Geophysical Research: Atmospheres 104, no. D15 (August 1, 1999): 18647–59. http://dx.doi.org/10.1029/1999jd900312.

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42

Hecht, J. H., A. B. Christensen, D. J. Gutierrez, D. C. Kayser, W. E. Sharp, J. R. Sharber, J. D. Winningham, R. A. Frahm, D. J. Strickland, and D. J. McEwen. "Observations of the neutral atmosphere between 100 and 200 km using ARIA rocket-borne and ground-based instruments." Journal of Geophysical Research 100, A9 (1995): 17285. http://dx.doi.org/10.1029/95ja00229.

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43

Reichle, Henry G., Vickie S. Connors, J. Alvin Holland, Warren D. Hypes, H. Andrew Wallio, Joseph C. Casas, Barbara B. Gormsen, Mary S. Saylor, and Wilfred D. Hesketh. "Middle and upper tropospheric carbon monoxide mixing ratios as measured by a satellite-borne remote sensor during November 1981." Journal of Geophysical Research 91, no. D10 (1986): 10865. http://dx.doi.org/10.1029/jd091id10p10865.

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44

Wang, Xihong, and Diane V. Michelangeli. "Comparison of microphysical modeling of polar stratospheric clouds against balloon-borne and Improved Limb Atmospheric Spectrometer (ILAS) satellite observations." Journal of Geophysical Research: Atmospheres 111, no. D10 (May 18, 2006): n/a. http://dx.doi.org/10.1029/2005jd006222.

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45

Suortti, T., J. Karhu, R. Kivi, E. Kyrö, J. Rosen, N. Kjome, N. Larsen, et al. "Evolution of the Arctic stratospheric aerosol mixing ratio measured with balloon-borne aerosol backscatter sondes for years 1988-2000." Journal of Geophysical Research: Atmospheres 106, no. D18 (September 1, 2001): 20759–66. http://dx.doi.org/10.1029/2000jd000180.

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46

Rosen, James M., Raymond M. Morales, Norman T. Kjome, Volker W. J. H. Kirchhoff, and Francisco R. da Silva. "Equatorial aerosol-ozone structure and variations as observed by balloon-borne backscattersondes since 1995 at Natal, Brazil (6°S)." Journal of Geophysical Research: Atmospheres 109, no. D3 (February 3, 2004): n/a. http://dx.doi.org/10.1029/2003jd003715.

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47

Lettvin, Ellen E., and John F. Vesecky. "Estimation of wind friction velocity and direction at the ocean surface from physical models and space-borne radar scatterometer measurements." Journal of Geophysical Research: Oceans 106, no. C10 (October 15, 2001): 22503–19. http://dx.doi.org/10.1029/1999jc000077.

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48

Vonnegut, B., R. Markson, and C. B. Moore. "Comment on “Factor of 2 error in balloon-borne, atmospheric conduction current measurements” by A. A. Few and A. J. Weinheimer." Journal of Geophysical Research 92, no. D4 (1987): 4337. http://dx.doi.org/10.1029/jd092id04p04337.

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49

Markson, Ralph. "Comment on “Factor of 2 error in balloon-borne atmospheric conduction current measurements” by A. A. Few and A. J. Weinheimer." Journal of Geophysical Research 92, no. D9 (1987): 11003. http://dx.doi.org/10.1029/jd092id09p11003.

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50

Sobral, J. H. A., H. Takahashi, M. A. Abdu, P. Muralikrishna, Y. Sahai, C. J. Zamlutti, E. R. de Paula, and P. P. Batista. "Determination of the quenching rate of the O(¹D) by O(³P) from rocket-borne optical (630 nm) and electron density data." Journal of Geophysical Research: Space Physics 98, A5 (May 1, 1993): 7791–98. http://dx.doi.org/10.1029/92ja01839.

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