scholarly journals Satellite data interpretation of causes and controls on groundwater-seawater flow directions, Merseyside, UK: implications for assessing saline intrusions

2005 ◽  
Vol 2 (3) ◽  
pp. 887-916 ◽  
Author(s):  
S. Mukherjee ◽  
E. A. Mohammad ◽  
R. H. Worden
Keyword(s):  
Satellite Data ◽  
Intertidal Zone ◽  
Near Infrared ◽  
Water Movement ◽  
Coastal Region ◽  
Chloride Concentration ◽  
Fault Zones ◽  
Fault Rocks ◽  
Grain Crushing ◽  
Clay Deposits

Abstract. Groundwater in the Triassic Sherwood Sandstone aquifer, Liverpool, UK, has locally elevated chloride concentrations (~4000 mg/l) in parts of the coastal region although there is freshwater right up to the coast line in other areas. The aquifer is cut my numerous faults with vertical displacements of as much 300 m. SPOT satellite data have been used for the Merseyside area of Liverpool. The satellite data revealed and confirmed the location of some of the main faults since the fault zones of the aquifer have low permeability (due to grain crushing, cataclasis, and clay smearing). Where fault zones outcrop at the surface, below the well-developed regolith, there is locally elevated soil water and thus anomalous vegetation patterns in comparison to unfaulted and highly porous aquifer. The ability to identify fault zones by this satellite-based method strongly suggests that they are at least partially sealing, sub-vertical features in the aquifer. Digitally enhanced and processed satellite data were used to define the relative proportions of sand and clay in the near-coastal (inter-tidal) part of the Mersey estuary. Sand-dominated sediment has higher pixel values in comparison with clay deposits in the near infrared spectral region (NIR). Where open and weathered fault rocks crop out at the surface near the intertidal zone, water movement in these potential surface water conduits is limited where the intertidal zone is clay-dominated since clay will plug the conduit. Where these weathered and open fault-rocks crop out against sand-dominated parts of the coastline, fresh water outflux into the seawater has been imaged using the satellite data. Furthermore, the high and low chloride concentration parts of the aquifer are separated by major, sub-vertical fault zones and have allowed a very steep water table gradient to remain in the aquifer.

scholarly journals Use of multi-spectral visible and near-infrared satellite data for timely estimates of the Earth's surface reflectance in cloudy conditions: Part 2 - image restoration with HICO satellite data in overcast conditions

2021 ◽  
Author(s):  
Joanna Joiner ◽  
Zachary Fasnacht ◽  
Bo-Cai Gao ◽  
Wenhan Qin
Keyword(s):  
Spatial Resolution ◽  
Satellite Data ◽  
Precision Agriculture ◽  
Land Surface ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Space Station ◽  
Water Quality Assessment ◽  
Low Contrast

Satellite-based visible and near-infrared imaging of the Earth's surface is generally not performed in moderate to highly cloudy conditions; images that look visibly cloud covered to the human eye are typically discarded. Here, we expand upon previous work that employed machine learning (ML) to estimate underlying land surface reflectances at red, green, and blue (RGB) wavelengths in cloud contaminated spectra using a low spatial resolution satellite spectrometer. Specifically, we apply the ML methodology to a case study at much higher spatial resolution with the Hyperspectral Imager for the Coastal Ocean (HICO) that flew on the International Space Station (ISS). HICO spatial sampling is of the order of 90 m. The purpose of our case study is to test whether high spatial resolution features can be captured using multi-spectral imaging in lightly cloudy and overcast conditions. We selected one clear and one cloudy image over a portion ofthe panhandle coastline of Florida to demonstrate that land features are partially recoverable in overcast conditions. Many high contrast features are well recovered in the presence of optically thin clouds. However, some of the low contrast features, such as narrow roads, are smeared out in the heavily clouded part of the reconstructed image. This case study demonstrates that our approach may be useful for many science and applications that are being developed for current and upcoming satellite missions including precision agriculture and natural vegetation analysis, water quality assessment as well as disturbance, change, hazard, and disaster detection.

scholarly journals Retrieval and Validation of Water Turbidity at Metre-Scale Using Pléiades Satellite Data: A Case Study in the Gironde Estuary

2020 ◽  
Vol 12 (6) ◽  
pp. 946 ◽  
Author(s):  
Yafei Luo ◽  
David Doxaran ◽  
Quinten Vanhellemont
Keyword(s):  
Spatial Variability ◽  
Satellite Data ◽  
Near Infrared ◽  
Atmospheric Correction ◽  
Field Measurements ◽  
Quality Parameters ◽  
Satellite Constellations ◽  
Water Turbidity ◽  
Gironde Estuary ◽  
The Difference

This study investigated the use of frequent metre-scale resolution Pléiades satellite imagery to monitor water quality parameters in the highly turbid Gironde Estuary (GE, SW France). Pléiades satellite data were processed and analyzed in two representative test sites of the GE: 1) the maximum turbidity zone and 2) the mouth of the estuary. The main objectives of this study were to: (i) validate the Dark Spectrum Fitting (DSF) atmospheric correction developed by Vanhellemont and Ruddick (2018) applied to Pléiades satellite data recorded over the GE; (ii) highlight the benefits of frequent metre-scale Pléiades observations in highly turbid estuaries by comparing them to previously validated satellite observations made at medium (250/300 m for MODIS, MERIS, OLCI data) and high (20/30 m for SPOT, OLI and MSI data) spatial resolutions. The results show that the DSF allows for an accurate retrieval of water turbidity by inversion of the water reflectance in the near-infrared (NIR) and red wavebands. The difference between Pléiades-derived turbidity and field measurements was proven to be in the order of 10%. To evaluate the spatial variability of water turbidity at metre scale, Pléiades data at 2 m resolution were resampled to 20 m and 250 m to simulate typical coarser resolution sensors. On average, the derived spatial variability in the GE is lower than or equal to 10% and 26%, respectively, in 20-m and 250-m aggregated pixels. Pléiades products not only show, in great detail, the turbidity features in the estuary and river plume, they also allow to map the turbidity inside ports and capture the complex spatial variations of turbidity along the shores of the estuary. Furthermore, the daily acquisition capabilities may provide additional advantages over other satellite constellations when monitoring highly dynamic estuarine systems.

scholarly journals Fault Rocks of the Moine Thrust Zone: A Guide to Their Nomenclature

1982 ◽  
Vol 4 (4) ◽  
pp. 211-221 ◽  
Author(s):  
S. White
Keyword(s):  
Shear Strain ◽  
Country Rock ◽  
Fault Zones ◽  
Fault Rocks ◽  
Fine Grained ◽  
Fine Grain ◽  
Simple Set ◽  
Thrust Zone ◽  
Moine Thrust Zone

The aim of this article is to extract from the existing literature a consistent nomenclature that can be used in the description of coherent fault rocks. The nomenclature is dealt with in this paper. Typical microstructures illustrating each is presented in a later paper (White et al ., 1982). It will be shown that a simple set of nomenclature can be extracted from the literature, so long as genetic connotations are kept to a minimum. The sequence, with increasing shear strain is country rock–protomylonite–blastomylonite–mylonite–ultramylonite if the rock has a well developed foliation; country rock–protocataclasite–cataclasite–ultracataclasite if it is without a foliation.It is emphasized that a mylonite is basically a fine-grained schist that has formed within fault zones. It is the association with faulting that distinguishes a mylonite from a fine grain schist.

scholarly journals Spatial and temporal variation in CO over Alberta using measurements from satellites, aircraft, and ground stations

2015 ◽  
Vol 15 (7) ◽  
pp. 3893-3908 ◽  
Author(s):  
H. S. Marey ◽  
Z. Hashisho ◽  
L. Fu ◽  
J. Gille
Keyword(s):  
Carbon Monoxide ◽  
Biomass Burning ◽  
Satellite Data ◽  
Forest Fires ◽  
Oil Sands ◽  
Near Infrared ◽  
Spatial And Temporal Variation ◽  
Peak Time ◽  
Northern Alberta ◽  
Urban Sites

Abstract. Alberta is Canada's largest oil producer, and its oil sands deposits comprise 30% of the world's oil reserves. The process of bitumen extraction and upgrading releases trace gases and aerosols to the atmosphere. In this study we present satellite-based analysis to explore, for the first time, various contributing factors that affect tropospheric carbon monoxide (CO) levels over Alberta. The multispectral product that uses both near-infrared (NIR) and the thermal-infrared (TIR) radiances for CO retrieval from the Measurements of Pollution in the Troposphere (MOPITT) is examined for the 12-year period from 2002 to 2013. The Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly product from 2001 to 2013 is employed to investigate the seasonal and temporal variations in forest fires. Additionally, in situ CO measurements at industrial and urban sites are compared to satellite data. Furthermore, the available MOZAIC/IAGOS (Measurement of Ozone, Water Vapor, Carbon Monoxide, Nitrogen Oxide by Airbus In-Service Aircraft/In service Aircraft for Global Observing System) aircraft CO profiles (April 2009–December 2011) are used to validate MOPITT CO data. The climatological time curtain plot and spatial maps for CO over northern Alberta indicate the signatures of transported CO for two distinct biomass burning seasons: summer and spring. Distinct seasonal patterns of CO at the urban sites (Edmonton and Calgary) point to the strong influence of traffic. Meteorological parameters play an important role in the CO spatial distribution at various pressure levels. Northern Alberta shows a stronger upward lifting motion which leads to larger CO total column values, while the poor dispersion in central and southern Alberta exacerbates the surface CO pollution. Interannual variations in satellite data depict a slightly decreasing trend for both regions, while the decline trend is more evident from ground observations, especially at the urban sites. MOPITT CO vertical averages and MOZAIC/IAGOS aircraft profiles were in good agreement within the standard deviations at all pressure levels. There is consistency between the time evolution of high-CO episodes monitored by satellite and ground measurements and the fire frequency peak time, which implies that biomass burning has affected the tropospheric CO distribution in northern Alberta. These findings have further demonstrated the potential use of the MOPITT V5 multispectral (NIR + TIR) product for assessing a complicated surface process.

Thermophysical reservoir properties of the Hauptdolomit-facies underneath the Viennese basin across fault zones analogues – a reservoir study for the GeoTief EXPLORE project

2020 ◽  
Author(s):  
Doris Rupprecht ◽  
Sven Fuchs ◽  
Andrea Förster ◽  
Mariella Penz-Wolfmayr
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Fractured Rocks ◽  
Damage Zone ◽  
Fault Zones ◽  
Rock Properties ◽  
Zone Model ◽  
Geothermal Resources ◽  
Fault Rocks ◽  
The Impact

<p>The GeoTief EXPLORE project aims to explore the geothermal potential and quantify the geothermal resources of the Vienna Basin (Austria) and the underlying Northern Calcareous Alpine basement. The main target of geothermal interest is the massive and tectonically remolded Hauptdolomite facies that has been identified as potential geothermal reservoir in previous studies. Now, this formation is studied using outcrop analogues for the investigation of their petrophysical characterization and specific thermal properties (thermal conductivity and thermal diffusivity).</p><p> </p><p>Here, we report new measurements on a total of 60 samples from 6 outcrops in and around the area of Vienna applying different methods for the laboratory measurement of thermal and hydraulic rock properties. The petrophysical analysis considers the impact of deformation along and across fault zones, which introduces heterogeneity of storage properties and consequently in the thermophysical properties. Using the standard fault core and damage zone model, outcrop samples were grouped into unfractured and fractured protoliths, as well as in fault rocks, like breccias and cataclasites. Rock samples are then classified by their fracture density (m² fracture surface per m³ rock) and by their matrix content and differences in grain sizes, respectively.</p><p> </p><p>The measured thermal rock properties vary significantly between the selected rock groups. The total range [90 % of values] is between 3.2 and 5.0 W/(mK) for thermal conductivity and between 1.3 and 2.7 mm²/s for thermal diffusivity. The results generally met the expected trend for fractured rocks as conductivity and diffusivity decreases with increasing porosity under unsaturated and saturated conditions. The total porosities are less than 5%. The variability of thermal conductivity under saturated conditions shows complex trends depending on the different rock classifications where fault rocks and highly fractured rocks of the damage zone show lower increase in thermal conductivities.</p><p> </p><p>The new petrophysical characterization will be the base for further numerical investigations of the hydraulic and thermal regime as well as for the analysis of the geothermal resources of the Hauptdolomite.</p><p> </p><p> </p><p> </p><p> </p>

A spectrophotometric study of Fe(II)-chloride complexes in aqueous solutions from 10 to 100°C

2001 ◽  
Vol 79 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Renhai Zhao ◽  
Pujing Pan
Keyword(s):  
Stability Constants ◽  
Near Infrared ◽  
Chloride Concentration ◽  
Pitzer Model ◽  
Nonlinear Least Squares ◽  
Ionic Species ◽  
Spectrophotometric Study ◽  
Chloride Complexes ◽  
Near Ir ◽  
Coordination Change

The absorption spectra of Fe(II)-chloride solutions were measured in both the UV (ultraviolet) and near-IR (near infrared) regions at temperatures ranging from 10 to 100°C with chloride concentrations from 0.1 to 16 mol kg-1. The stability constants of all Fe(II)-chloride complexes were derived from the spectra using a non-negative nonlinear least-squares computer program (SQUAD). Earlier work on this system reported in the literature was rigorously reassessed. The activity coefficients of the ionic species were calculated using both the Pitzer model and the Helgeson model. The results obtained with UV and near-IR spectra and with different activity coefficient calculation models are in general agreement. Other useful thermodynamic data, including the Gibbs energies, enthalpies, and entropies for complex formation, were also obtained. It was found that the Fe(II)-chloride complexes gradually undergo a configuration transformation from octahedral to tetrahedral coordination as the temperature and (or) chloride concentration increases. This coordination change is of significant importance to the nuclear reactors, as the presence of the tetrahedral complex can increase the solubility of iron in steam generator crevices.Key words: Fe(II)-chloride complexes, stability constants, solution thermodynamics, spectrophotometry, reactor chemistry.

scholarly journals Hoar crystal development and disappearance at Dome C, Antarctica: observation by near-infrared photography and passive microwave satellite

2013 ◽  
Vol 7 (1) ◽  
pp. 175-217 ◽  
Author(s):  
N. Champollion ◽  
G. Picard ◽  
L. Arnaud ◽  
E. Lefebvre ◽  
M. Fily
Keyword(s):  
Wind Speed ◽  
Satellite Data ◽  
Wind Direction ◽  
Near Infrared ◽  
Microwave Remote Sensing ◽  
Passive Microwave ◽  
Infrared Photography ◽  
Surface Mass ◽  
Prevailing Direction ◽  
Strong Winds

Abstract. Hoar crystals episodically cover the snow surface in Antarctica and affect the roughness and reflective properties of the air-snow interface. However, little is known about their evolution and the processes responsible for their development and disappearance despite a probable influence on the surface mass balance and energy budget. To investigate hoar evolution, we use continuous observations of the surface by in-situ near-infrared photography and by passive microwave remote sensing at Dome C in Antarctica. From the photography data, we retrieved a daily indicator of the presence/absence of hoar crystals using a texture analysis algorithm. The analysis of this 2-yr long time series shows that Dome C surface is covered almost half of the time by hoar. The development of hoar crystals takes a few days and seems to occur whatever the meteorological conditions. In contrast, the disappearance of hoar is rapid (a few hours) and coincident with either strong winds or with moderate winds associated with a change in wind direction from Southwest (the prevailing direction) to Southeast. From the microwave satellite data, we computed the polarisation ratio (i.e. horizontal over vertical polarised brightness temperatures), an indicator known to be sensitive to hoar in Greenland. Photography data and microwave polarisation ratio are correlated, i.e. high values of polarisation ratio which theoretically correspond to low snow density values near the surface are associated with the presence of hoar crystals in the photography data. Satellite data over nearly ten years (2002–2011) confirm that a strong decrease of the polarisation ratio (i.e. signature of hoar disappearance) is associated with an increase of wind speed or a change in wind direction from the prevailing direction. The photography data provides, in addition, evidence of interactions between hoar and snowfall. Further adding the combined influence of wind speed and wind direction results in a complex picture of the snow-atmosphere interactions in Antarctica which deserves further quantification and modelling.

scholarly journals CORRELATION ANALYSIS OF SATELLITE DATA ON CARBON DIOXIDE EMISSIONS AND VEGETATION INDEXES IN THE TERRITORY OF DONBASS

2020 ◽  
Vol 2 (5) ◽  
pp. 104-110
Author(s):  
F.V. Nedopekin ◽  
◽  
N.S. Shestavin ◽  
V.V. Yurchenko ◽  
◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Satellite Data ◽  
Carbon Dioxide Emissions ◽  
Power Plants ◽  
Near Infrared ◽  
Thermal Power ◽  
Anthropogenic Sources ◽  
The Black Sea ◽  
Control Points ◽  
Vegetation Indexes

Using the Emissions Database for Global Atmospheric Research satellite data on the annual global carbon dioxide emissions, their distributions in the Donbass were obtained for the period from 2013 to 2018, indicating their main anthropogenic sources: large cities, thermal power plants and metallurgical plants. Control points were selected near and far from the largest sources of carbon dioxide emissions and, with the help of the resources of the Shared Use Center, systems for archiving, processing and analysis of satellite data of the Institute of Space Research of the Russian Academy of Sciences, the average annual vegetation indexes in the territory of Donbass and at control points for the same period of time were determined. A comparison was made of the reflection intensities in the near infrared and red regions of the spectrum, as well as the normalized relative vegetation indexes at these control points. It is indicated that there is no direct correlation between the values of vegetation indexes and the concentration of carbon dioxide in a given period of time. A sharp decrease in the volume of biomass was noted in a number of control points due to the appearance of signs of drought in the Black Sea region, as well as a significant increase in wild vegetation in the conflict zone in the eastern regions of Donbass.

Acute effects of brief ureteral stasis on urinary and renal papillary chloride concentration

1960 ◽  
Vol 199 (6) ◽  
pp. 1215-1218 ◽  
Author(s):  
Richard H. Kessler
Keyword(s):  
Water Movement ◽  
Collecting Duct ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Contralateral Side ◽  
Acute Effects ◽  
Duct Epithelium ◽  
Collecting Duct Epithelium ◽  
Filtered Load

According to the countercurrent hypothesis urine tonicity depends largely on osmotic equilibrium of collecting duct fluid with the hypertonic interstitium of the papilla. One suggested role of ADH is that of regulating water permeability of collecting duct epithelium. In water deprivation ADH would facilitate water movement from collecting duct to the hypertonic papilla. Support for this hypothesis is offered here. These studies use the observation that ureteral clamping curtails glomerular filtration. Hence, the filtered load of NaCl from which papillary stores are derived is reduced. Accordingly, the chloride content of papillary tissues obtained from dog kidneys subsequent to several minutes of ureteral clamping was compared to those from the opposite kidney. In saline-loaded animals stasis uniformly lowered tissue chloride with the production of urine lower in chloride content and hypotonic to that of the contralateral side. These alterations were minimized following urinary stasis in animals loaded with water, mannitol or saline plus ADH.

scholarly journals Determination of the Youngest Active Domain in Major Fault Zones Using Medical X-ray Computed Tomography-derived Density Estimations

2021 ◽  
Author(s):  
akiyuki iwamori ◽  
Hideo Takagi ◽  
Nobutaka Asahi ◽  
Tatsuji Sugimori ◽  
Eiji Nakata ◽  
...  
Keyword(s):  
Fault Zone ◽  
Atomic Number ◽  
Density Ratio ◽  
Effective Atomic Number ◽  
Fault Zones ◽  
Ct Number ◽  
Fault Rock ◽  
Fault Rocks ◽  
X Ray Computed

Abstract Determination of the youngest active domains in fault zones that are not overlain by Quaternary sedimentary cover are critical for evaluating recent fault activity, determining the current local stress field, and mitigating the impacts of future earthquakes. Considering the exhumation of a fault zone, the youngest active domain in a fault zone is supposed to correspond to the activity at the minimum fault depth of a buried fault, such that the most vulnerable area, which possesses the lowest rock/protolith density ratio, is assumed to be indicative of this recent fault activity. However, it is difficult to measure the density of fault rocks and map the rock/protolith density ratio across a given fault zone. Here we utilize medical X-ray computed tomography (CT), a non-destructive technique for observing and analyzing materials, to investigate the fault characteristics of several fault zones and their surrounding regions in Japan, and attempt to determine the youngest active domain of a given fault zone based on its CT numbers, which are a function of the density and effective atomic number of the fault rock and protolith. We first investigate the density, void ratio, and effective atomic number of active and inactive fault rocks, and their respective protoliths. We then calculate the CT numbers after reducing the beam-hardening effects on the rock samples, and study the relationships among the CT number, density, and effective atomic number. We demonstrate that the density, effective atomic number, and CT number of the fault rock decrease as the youngest active zone is approached, such that the region with the lowest CT number and rock/protolith density ratio defines the youngest active domain of a given fault zone.

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