A Comparison of Optimized Sentinel-2 Super-Resolution Methods Using Wald’s Protocol and Bayesian Optimization

In the context of earth observation and remote sensing, super-resolution aims to enhance the resolution of a captured image by upscaling and enhancing its details. In recent years, numerous methods for super-resolution of Sentinel-2 (S2) multispectral images have been suggested. Most of those methods depend on various tuning parameters that affect how effective they are. This paper’s aim is twofold. Firstly, we propose to use Bayesian optimization at a reduced scale to select tuning parameters. Secondly, we choose tuning parameters for eight S2 super-resolution methods and compare them using real and synthetic data. While all the methods give good quantitative results, Area-To-Point Regression Kriging (ATPRK), Sentinel-2 Sharpening (S2Sharp), and Sentinel-2 Symmetric Skip Connection convolutional neural network (S2 SSC) perform markedly better on several datasets than the other methods tested in this paper

Analytical geochemical studies on cadmium and some other trace metals in estuarine and coastal environments

A method involving acid digestion, dithizone extraction and atomic absorption spectrometry was developed to determine cadmium, zinc, copper, nickel, cobalt, silver and bismuth in sediments. The determination of lead and indium was also investigated but accurate methods were not developed. A demountable hollow cathode lamp was successfully employed for work on bismuth and indium. Modifications of the method made possible the determination of cadmium, zinc, lead, copper, nickel, cobalt and silver in biological tissues and in natural waters. Precision values were obtained on sediment samples from Southampton Water and the North Atlantic Ocean, Solent sea water samples and a sample of reference kale, and are listed along with detection limits in the following table. Matrix Cd Zn Pb Cu Ni Co Ag iij Cv DI Cv DI v DI V DI V DI Cv DI Cv DI Cv DI Typo I °6 1,n/g pg/o pn/g pg/0 n/s v PO/n po/n 6 ps/nMorinent 10 0,03 7 2,0 4 0,20 2 0 35 3 0,05 26 0,05 7 0,01 SedimeSo. Water 3 0,05 6 0,6 23 0,1 6 0,06 5 0,3 12 0,05 29 0,0513, Geological 7 0,03 3 0,6 13 0,03 4 0,05 11 0,03 15 0,01 0,01 TissueCv : Coefficient of variation DI : Detection limit The method was used on United States Geological Survey rock reference samples and on reference kale and good agreement with listed values found.A technique involving successive leaching with magnesium chloride, Chester-Hughes reagent and basic sodium pyrophosphate followed by hydrofluoric acid digestion was developed to determine the distribution of trace metals between the major sediment components. Iron, manganese, organic carbon, hydrocarbons, free water content and particle size were determined as well as the above trace metals in some samples used in studies on sediments from Southampton Water, the Bristol Channel, the River Liffey and a part of the North Atlantic Ocean. Correlations were often found between cadmium, zinc, copper, nickel, cobalt and silver, especially in polluted situations. Sediments were polluted in the vicinity of the Fawley Oil Refinery, copper being the most enriched trace metal. Manganese, iron, calcium, magnesium, zinc, copper, nickel and cobalt were determined in samples of a deposit, consisting of manganese and iron-rich smectite concretions, from the summit area of Mount Palinuro, a seamount in the Tyrrhenian Sea. The trace metal patterns along with other information were used to establish that the deposit is hydrothermal in origin and that Mount Palinuro is a recently active volcano.</p

Uranium speciation in groundwaters from Parana basin, Brazil

This paper describes the results of a regional study involving the sampling of 60 pumped tubular wells drilled at the Parana sedimentary basin, Brazil, which was carried out with the purpose of evaluating the U speciation in the Botucatu-Piramboia aquifer. Uranium proved to be intensively dissolved even under the enhanced reducing conditions occurring at the most confined zones of the aquifer, and Eh-pH diagrams were utilized to evaluate the influence of temperature and pressure on the migration of the U-species within the aquifer

Soliloquy

Cover for Soliloquy, from the RISD Library Zine Collection.https://digitalcommons.risd.edu/specialcollections_zinecollection/1036/thumbnail.jp

Indirect detection of subsurface outflow from a Rift Valley lake

Naivasha, highest of the Kenya (Gregory) Rift Valley lakes, has no surface outlet. However, unlike other Rift lakes it has not become saline despite high potential evaporation rates, which indicates that there must be some subsurface drainage. The fate ofthis outflow has been the subject of speculation for many years, especially during the general decline in lake water level during the I980's. Particularly to the south of the lake, there are few opportunities to obtain information from direct groundwater sampling. However, the stable isotopic composition of fumarole steam from late Quaternary volcanic centres in the area has been used to infer groundwater composition. Using a simple mixing model between Rift-flank groundwater and highly-evaporated lakewater, this has enabled subsurface water flow to be contoured by its lakewater content. By this method, outflow can still be detected some 30 km to the south of the lake. Stable isotope data also confirm that much of the steam used by the local Olkaria geothermal power station is derived from lakewater, though simple balance considerations show that steam use cannot alone be responsible for the fall in lake level observed during the 1980's

CO2 emissions and heat flow through soil, fumaroles, and steam heated mud pools at the Reykjanes geothermal area, SW Iceland

Carbon dioxide emissions and heat flow through soil, steam vents and fractures, and steam heated mud pools were determined in the Reykjanes geothermal area, SW Iceland. Soil diffuse degassing of CO2 was quantified by soil flux measurements on a 600 m by 375 m rectangular grid using a portable closed chamber soil flux meter and the resulting data were analyzed by both a graphical statistical method and sequential Gaussian simulations. The soil temperature was measured in each node of the grid and used to evaluate the heat flow. The heat flow data were also analyzed by sequential Gaussian simulations. Heat flow from steam vents and fractures was determined by quantifying the amount of steam emitted from the vents by direct measurements of steam flow rate. The heat loss from the steam heated mud pools was determined by quantifying the rate of heat loss from the pools by evaporation, convection, and radiation. The steam flow rate into the pools was calculated from the observed heat loss from the pools, assuming that steam flow was the only mechanism of heat transport into the pool. The CO2 emissions from the steam vents and mud pools were determined by multiplying the steam flow rate from the respective sources by the representative CO2 concentration of steam in the Reykjanes area. The observed rates of CO2 emissions through soil, steam vents, and steam heated mud pools amounted to 13.5 ± 1.7, 0.23 ± 0.05, and 0.13 ± 0.03 tons per day, respectively. The heat flow through soil, steam vents, and mud pools was 16.9 ± 1.4, 2.2 ± 0.4, and 1.2 ± 0.1 MW, respectively. Heat loss from the geothermal reservoir, inferred from the CO2 emissions through the soil amounts to 130 ± 16 MW of thermal energy. The discrepancy between the observed heat loss and the heat loss inferred from the CO2 emissions is attributed to steam condensation in the subsurface due to interactions with cold ground water. These results demonstrate that soil diffuse degassing can be a more reliable proxy for heat loss from geothermal systems than soil temperatures. The soil diffuse degassing at Reykjanes appears to be strongly controlled by the local tectonics. The observed diffuse degassing defines 3–5 elongated N–S trending zones (000–020 ). The orientation of the diffuse degassing structures at Reykjanes is consistent with reported trends of right lateral strike slip faults in the area. The natural CO2 emissions from Reykjanes under the current low-production conditions are about 16% of the expected emissions from a 100 MWe power plant, which has recently been commissioned at Reykjanes

The origin of hydrothermal and other gases in the Kenya Rift Valley

The Kenya Rift Valley (KRV) is part of a major continental rift system from which much outgassing is presently occurring. Previous research on gases in the KRV has tended to concentrate on their geothermal implications; the present paper is an attempt to broaden the interpretation by consideration of new data including helium and carbon isotope analyses from a wide cross-section of sites. In order to do this, gases have been divided into categories dependent on origin. N2 and noble gases are for the most part atmospherically derived, although their relative concentrations may be altered from ASW ratios by various physical processes. Reduced carbon (CH4 and homologues) appears to be exclusively derived from the shallow crust, with thermogenic δ13C values averaging −25‰ PDB for CH4. H2 is likely also to be crustally formed. CO2, generally a dominant constituent, has a narrow δ13C range averaging −3.7‰ PDB, and is likely to be derived with little modification from the upper mantle. Consideration of the ratio C/3He supports this view in most cases. Sulphur probably also originates there. Ratios of 3He/4He reach a MORB-like maximum of 8.0 R/RA and provide the best indication of an upper mantle source of gases beneath the KRV. A correlation between 3He/4He and the hydrocarbon parameter log (C1/ΣC2–4) appears to be primarily temperature related. The highest 3He/4He ratios in spring waters are associated with basalts, perhaps because of the leaching of basalt glasses. There may be a structural control on 3He/4He ratios in the KRV as a whole