Miracle-dz/UniFAR-FTUs huggingface dataset:
Detection of layering in the upper cloud layer of Venus northern polar atmosphere observed from radio occultation data

[1] Observations of radio wave scintillations represent an important tool for measuring of small-scale irregularities in the atmosphere of Venus. Prominent features of enhanced scintillation located in the 60-km region were observed in Mariners 5 and 10, Venera 9, and Pioneer Venus occultations. It is possible that the enhanced scintillations are due to the random turbulence in the upper region which is caused by trapped small-scale gravity waves. However, other interpretations are possible. Thin stable layers, which are commonly observed in the Earth stratosphere under cloud-free conditions, could also contribute to scattering in the Venus stratosphere. If scintillations observed in different occultations are correlated, then these scintillations may be attributed to the persistent layers. Cross correlations of 32-cm radio wave amplitude fluctuations have been determined for seven radio occultation measurements of Venus’s northern polar atmosphere using Venera 15 and 16. Significant cross correlations were found between 59.0 and 61.5 km in four different radio occultations. Layering is revealed in the upper layer of the Venus clouds at altitudes of 59.0–61.5 km, which is specified by enhanced turbulence of the atmosphere. It is found that the lifetime of the small-scale layered irregularities is 2 d or more and that their horizontal extension in the meridional direction can exceed 180 km. A possible cause of emergence of the layered structures inside the upper layer of polar clouds of Venus is discussed.
New estimates of radiative forcing due to well mixed greenhouse gases

We have performed new calculations of the radiative forcing due to changes in the concentrations of the most important well mixed greenhouse gases (WMGG) since pre‐industrial time. Three radiative transfer models are used. The radiative forcing due to CO2, including shortwave absorption, is 15% lower than the previous IPCC estimate. The radiative forcing due to all the WMGG is calculated to 2.25 Wm−2, which we estimate to be accurate to within about 5%. The importance of the CFCs is increased by about 20% relative to the total effect of all WMGG compared to previous estimates. We present updates to simple forcing‐concentration relationships previously used by IPCC.
Global and regional sea level change during the 20th century

Sea level variations prior to the launch of satellite altimeters are estimated by analyzing historic tide gauge records. Recently, a number of groups have reconstructed sea level by applying EOF techniques to fill missing observations. We complement this study with alternative methods. In a first step gaps in 178 records of sea level change are filled using the pattern recognition capabilities of artificial neural networks. Afterward satellite altimetry is used to extrapolate local sea level change to global fields. Patterns of sea level change are compared to prior studies. Global mean sea level change since 1900 is found to be 1.77±0.38 mm yr−1 on average. Local trends are essentially positive with the highest values found in the western tropical Pacific and in the Indian Ocean east of Madagascar where it reaches about +6 mm yr−1. Regions with negative trends are spotty with a minimum value of about −2 mm yr−1 south of the Aleutian Islands. Although the acceleration found for the global mean, +0.0042 ± 0.0092 mm yr−2, is not significant, local values range from −0.1 mm yr−2 in the central Indian Ocean to +0.1 mm yr−2 in the western tropical Pacific and east of Japan. These extrema are associated with patterns of sea level change that differ significantly from the first half of the analyzed period (i.e., 1900–1950) to the second half (1950–2000). We take this as an indication of long period oceanic processes that are superimposed to the general sea level rise.
Thermal emission spectroscopy of the silica polymorphs and considerations for remote sensing of Mars

The possible existence of silica‐rich rocks on Mars requires consideration of all of the candidate forms of silica that might exist there. We synthesized coesite and cristobalite, and obtained natural samples of tridymite, opal‐A, and opal‐CT. The thermal emission spectra of these silica phases were analyzed and related to their crystal structure and crystallinity. Structural differences between the polymorphs result in unique spectral character and the degree and type of crystal ordering in opal‐CT results in cristobalite‐ or tridymite‐like spectral features. These spectra will be useful for analysis of Thermal Emission Spectrometer (TES) data from Mars. While silica polymorphs are not modeled in deconvolution of the two main TES surface‐type spectra, this does not preclude the possible detection of local abundances of these minerals on Mars. Spectral detection of silica phases on Mars would have implications for the volcanic and alteration history of the planet.
MEASURING HYDRAULIC CONDUCTIVITY IN A CRACKING CLAY SOIL USING THE GUELPH PERMEAMETER

Knowing the variation of field-saturated hydraulic conductivity (Kfs) with space, time and antecedent soil moisture conditions can be important for optimum management of cracking clay soils. The Guelph Permeameter (GP) method is a potentially valuable technique for measuring Kfs and its variation in cracking soils, but concerns exist regarding (1) impacts of smearing and compaction in the GP well on the Kfs measurement, (2) accurate detection of when steady flow from the GP is attained, and (3) time required for the GP to reach steady flow (equilibration time). These concerns were investigated for a series of GP measurements in a cracking clay soil (Vertic Xerochrept) in Sicily by testing a plucking implement for removal of smearing and compaction, and by comparing three approaches for detecting steady flow and equilibration time. The mean Kfs values (11.4-22.1 mm h–1) obtained from the GP measurements were 1-3 orders of magnitude larger than what might be expected for a clayey texture, indicating that ponded infiltration from the GP wells occurred primarily through highly permeable soil shrinkage cracks, rather than through the low permeability clayey matrix. Wells that were treated with the plucking implement produced a non-significant (P < 0.05) factor of 1.94 increase in mean Kfs relative to untreated wells, suggesting that this method for removing smearing and compaction functioned primarily by reopening partially smeared-over shrinkage cracks or other macropores. Relatively short mean equilibration times were obtained for the GP measurements (11-42 min), suggesting that the GP method can measure the soil’s antecedent Kfs before wetting from the well causes enough soil swelling to produce a declining permeability. The traditional “four equal readings” (FR) procedure for estimating GP equilibration time substantially underestimated the more recent “visual estimation” (VE) and the new “cumulative drop” (CD) procedures. This underestimation by the FR procedure resulted in overestimates of Kfs relative to the VE and CD procedures for Kfs values less than about 4 mm h–1. It was concluded that the GP method can be a viable technique for measuring Kfs in cracking clay soil.
Exact sparse recovery with L0 projections

Many applications (e.g., anomaly detection) concern sparse signals. This paper focuses on the problem of recovering a K-sparse signal x ∈ R/1×N, i.e., K << N and ∑N/i=1 1{xi ≠ 0} = K. In the mainstream framework of compressed sensing (CS), × is recovered from M linear measurements y = xS ∈ R/1×M, where S ∈ RN×M is often a Gaussian (or Gaussian-like) design matrix. In our proposed method, the design matrix S is generated from an α-stable distribution with α ≈ 0. Our decoding algorithm mainly requires one linear scan of the coordinates, followed by a few iterations on a small number of coordinates which are "undetermined" in the previous iteration. Our practical algorithm consists of two estimators. In the first iteration, the (absolute) minimum estimator is able to filter out a majority of the zero coordinates. The gap estimator, which is applied in each iteration, can accurately recover the magnitudes of the nonzero coordinates. Comparisons with linear programming (LP) and orthogonal matching pursuit (OMP) demonstrate that our algorithm can be significantly faster in decoding speed and more accurate in recovery quality, for the task of exact spare recovery. Our procedure is robust against measurement noise. Even when there are no sufficient measurements, our algorithm can still reliably recover a significant portion of the nonzero coordinates.
Glacial‐Holocene Biogenic Sedimentation Patterns in the South China Sea: Productivity Variations and Surface Water pCO2

A bathymetric transect of cores in the South China Sea extending from 4200-m to less than 1000-m water depth has been examined for glacial-interglacial changes in carbonate and organic carbon sedimentation. Typical “Pacific carbonate cycles” (high carbonate content during glacials and low carbonate content during interglacials) characterize cores from water depths deeper than 3500 m. In contrast, “Atlantic carbonate cycles” (low carbonate during glacials and high carbonate during interglacials) are observed in cores from depths shallower than 3000 m as a result of increased dilution of carbonate by terrigenous material during glacial low stands of sea level. Glacial-interglacial changes in the carbonate chemistry of South China Sea intermediate and deep waters resulted in significant changes in the positions of the carbonate compensation depth (CCD) and the aragonite compensation depth (ACD). During the last glacial the CCD and ACD were at least 400 and 1200 m deeper, respectively, than at present. Organic carbon accumulation rates in the South China Sea were approximately 2 times higher during the last glacial than the Holocene. Carbon isotopic analyses and C/N ratios of the organic matter indicate that only a small fraction of the increase in glacial organic carbon accumulation can be attributed to input of terrestrial carbon. On the basis of this we conclude that surface water productivity in the South China Sea was approximately 2 times higher during the last glacial maximum. This is consistent with previous studies which have demonstrated that glacial productivity was higher in low- to mid-latitude regions of the Atlantic and eastern Pacific. The deglacial decrease in organic carbon accumulation is accompanied by a decrease in δ13Corg. Using the relationship between δ13Corg and [CO2](aq) developed by Popp et al. [1989], we estimate that surface water pCO2 values in the South China Sea during the last 25,000 years were very similar to atmospheric CO2 concentrations.
Alteration, mineralization, and fluid evolution at the Eloise Cu-Au deposit, Cloncurry District, Northwest Queensland, Australia

The Eloise deposit (3.1 million metric tons, Mt,5.5% Cu, 1.4 g/t Au and 16 g/t Ag) is hosted by Proterozoic rocks of the Soldiers Cap Group in the Eastern fold belt of the Mount Isa inlier. The deposit is characterized by very high grade, chalcopyrite-pyrrhotite-rich mineralization hosted by mafic silicate alteration. Alteration and mineralization lie within and adjacent to a major shear zone. The main metasomatism comprised three stages. Early pervasive albite alteration (stage I) was overprinted by stage II hornblende-biotite-quartz veins and alteration; stage III chalcopyrite, pyrrhotite, magnetite, pyrite, calcite, quartz, chlorite, and actinolite replaced and brecciated the earlier mafic silicates. The lodes occupy a narrow portion of a zoned, mineralized system that is at least 2 km in length. Magnetite-pyrite-rich mineralization occurs in the south, with chalcopyrite-pyrrhotite-rich mineralization in the central lode zone, and pyrrhotite-rich mineralization in the north. The system has a distinct chemistry, with enriched Cu, Au, Ag, Co, Ni, and Zn.Fluid inclusions in pre-, syn- and late- to postmineralization veins indicate an evolving fluid history. Primary inclusions and associated hornblende-biotite assemblages in premineralization veins indicate a high-temperature fluid (450 degrees -600 degrees C), and salinity estimates suggest it was an ultrasaline brine (32-68 wt % total salts). Fluid inclusions in stage III quartz in mineralized veins display a wide range of homogenization temperatures ( approximately 100 degrees -500 degrees C), and gangue assemblages (actinolite-chlorite-muscovite) suggest mineralization was a cooler event (200 degrees -450 degrees C). Inclusions associated with the mineralization have a lower salinity (30-47 wt % total salts) than do premineralization inclusions, and variable fluid inclusion types occur within the same clusters, which may reflect fluid mixing. The ultrasaline nature of the fluids and preliminary sulfur isotope results (0.4-2.0ppm) suggest the ore fluid was predominantly magmatic. Metals were carried as chlorocomplexes and H 2 S was the dominant sulfur species. Important factors in ore deposition were a decrease in temperature and salinity, and sulfidation of Fe-silicates. Eloise is interpreted to be a structurally controlled, distal, magmatic, hydrothermal vein deposit.
Double-Averaged Open-Channel Flows with Small Relative Submergence

We investigate the turbulent structure of shallow open channel flows where the flow depth is too small (compared with the roughness height) to form a logarithmic layer but large enough to develop an outer layer where the flow is not directly influenced by the roughness elements. Since the log layer is not present, the displacement height d , which defines the position of the zero plane, and the shear velocity u* cannot be found by fitting the velocity data to the log law. However, these parameters are still very important because they are used for scaling flow statistics for the outer and roughness layers. In this paper we propose an alternative procedure for evaluating d in laboratory conditions, where d is found from additional experiments with the fully developed log layer. We also point out the appropriate procedure for evaluating the shear velocity u* for flows with low submergence. These procedures are applied to our own laboratory flume experiments with uniform sphere roughness, where velocities we.
Hinge Structure in Carbonicola pseudorobusta Trueman and Related Species

Wheelton hind in his Monograph on Carbonicola gave a critical review of what was known about hinge structure in that genus up to 1896; he described and figured the hinge structure in various species of Carbonicola, notably in shells which he referred to C. acuta (Sowerby). Since that time little has been published about hinge structure in Carbonicola. A paper by M. C. March on the structure and relationships of Carbonicola appears only to have been published in abstract (1913): In that, mention was made of the specialization of the ligament and “cardinal plateau” in the hinge line of Carbonicola, the “cardinal plateau” being grooved for the reception of an internal ligament. It was also stated that hinge structure was absent in C. antiqua, poorly represented in C. turgida and similar forms, and most highly developed in C. aquilina.
Harvesting of Nodularia spumigena in the Baltic Sea: Assessment of Potentials and Added Benefits

ABSTRACT Pechsiri, J.S. ; Risén, E. ; Malmström, M.E. ; Brandt, N. , and Gröndahl, F. , 2014. Harvesting of Nodularia spumigena in the Baltic Sea: assessment of potentials and added benefits. Interest to harvest wild cyanobacteria exists due to the environmental and socioeconomic risks during cyanobacteria blooms coupled with demands for nonterrestrial-based alternatives for biofuel sources. This research, therefore, sought to estimate the wild cyanobacteria harvesting potential using Nodularia spumigena, and using the Baltic Sea as the case study. Data from literature provided during years 2003–2009 were used to perform estimations. Additional benefits of harvesting were also assessed by estimating the nutrient removal and biogas production potentials from the harvested biomass. Results indicate that one boom unit has the potential to harvest approximately 3 to 700 kg dry weight of N. spumigena per hour depending on the algae concentration of the bloom. Results also suggest that nutrient removal and biogas production potentials provide substantial additional incentives to the harvesting operation during years of extensive and highly concentrated blooms. However, during nonextensive or nonconcentrated blooms such potentials are low. ABSTRAKT Intresset för skörd av cyanobakterieblomningar beror på de miljö- och socio-ekonomiska risker som blomningarna medför. Ytterligare en bidragande orsak till detta intresse är efterfrågan efter icke markbaserade biobränslealternativ. Denna studie ämnar därför att undersöka potentialen med skörd av vilt förekommande cyanobakterieblomningar med arten Nodularia spumigena och Östersjön som fallstudie. Litteraturdata från åren 2003–2009 användes för att kvantifiera blomningarna. Ytterligare fördelar med skörden utvärderades också genom en uppskattning av näringsreduktionens och biogasproduktions potentialen av den skördade biomassan. Resultat indikerar att en skördeenhet har potentialen att skörda uppskattningsvis 3 till 700 kg ts Nodularia spumigena per timme beroende på algblomningens koncentration. Resultaten indikerar dessutom att näringsreduktionsförmågan och biogasproduktionspotentialen tillhandahåller ytterligare substantiella incitament för skörd under år med omfattande och koncentrerade blomningar. Dessa ytterligare incitament är dock inte betydande under de år då blomningarna inte är omfattande och koncentrerade.
Retrieving parameters of bare soil surface roughness and soil water content under arid environment from ERS-1, -2 SAR data

Evaluation of the environmental and agricultural potential of arid lands is often limited by the lack of information on soil surface roughness and water content. The current study proposes an efficient method to retrieve these parameters of bare soil from single-channel ERS-1, -2 synthetic aperture radar (SAR) data. New equations were derived by combining the model for vertically co-polarized mode backscattering coefficient the model for the real part of dielectric constant and the empirical equation interrelating parameters of roughness. These equations allowed for calculation of the root mean square (RMS) height h of small surface roughness (h ≤ 1 cm) for naturally sandy, flat areas of the Negev desert (Israel) during dry periods when is extremely low and generally known. As soil roughness was found to be sufficiently constant under the arid environment, this study showed that calculated h could be reliably used to retrieve during the wet period. Statistical analysis of the relative errors of retrieved h and showed their high independence on the absolute values. Retrieved values of h and obtained from ERS-2 SAR data showed acceptable correlation with the direct ground measurements. Therefore, the effectiveness of the proposed methodology for h and retrieval was proved.
Turbulent transport and deposition of the Ito pyroclastic flow: Determinations using anisotropy of magnetic susceptibility

The Ito pyroclastic flow erupted about 22,000 years ago from Aira caldera in southern Kyushu, Japan. Flow directions were determined by anisotropy of magnetic susceptibility (AMS), which measured the preferential alignment of magnetite microphenocrysts, usually ≤0.25 mm in diameter. The microphenocrysts are aligned with the long axis of the clasts during strain and fracture in the vent. The grains are then deposited parallel to the flow direction with an imbrication. There is no evidence of rolling of clasts or nonflow parallel lineations, and thus AMS can be used to determine flow directions that occurred immediately before deposition. Beyond 30 km from the center of the caldera, flow directions were predominantly down paleogradient, indicating expanded flow and that the depositional system was gravity driven and largely decoupled from the transport system. Within 30 km, measured flow directions are random, indicating that sedimentation occurred from a depositional system that was closely coupled to the turbulent transport system. Individual flow directions at all sites except one varied more than the analytical error, demonstrating that a variety of flow directions existed even within a small area of the flow. This implies that the depositional system was turbulent.
Composite Mg II solar activity index for solar cycles 21 and 22

The Mg II core-to-wing index was first developed for the Nimbus 7 solar backscatter ultraviolet spectrometer (SBUV) instrument as an indicator of solar middle ultraviolet activity that is independent of most instrument artifacts. This index is defined as the ratio of the irradiance in the core of the unresolved Mg II doublet at 280 nm to the nearby continuum irradiance and measures solar variability on both rotational and solar cycle time scales. Mg II index data sets have also been derived for the NOAA 9 and NOAA 11 SBUV/2 instruments. The combined Mg II index data record from the Nimbus 7, NOAA 9, and NOAA 11 instruments presented in this paper extends from November 1978 to January 1992. Differences in the absolute value of the Mg II index and long-term response to solar variations due to differences in wavelength scale and band pass among the three instruments require the use of linear regression fits to create a single composite Mg II index data set which includes more than 13 years of data. This paper documents version 1.0 of the composite Mg II index data set, which has been widely distributed on CD-ROM. Using this composite data set, the change in 27-day running average of the Mg II index from solar maximum to solar minimum is approximately 8% for solar cycle 21 and approximately 9% for solar cycle 22 through January 1992. This difference is not statistically significant when the errors in the linear regression fits used to construct the composite Mg II index are considered. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets are developed for each instrument to estimate solar variability at mid-ultraviolet and near-ultraviolet wavelengths. A set of composite scale factors are derived for use with the composite Mg II index presented here. Near 205 nm, where solar irradiance variations are important for stratospheric photochemistry, the estimated change in irradiance during solar cycle 22 is approximately 10(±1)% using the composite Mg II index (version 1.0) and scale factors. However, the actual magnitude of ΔF205 is probably closer to 9% due to unconnected SBUV/2 wavelength scale drift in the current composite Mg II index data set.
Small Cruziana, rusophycus, and related ichnotaxa from eastern Canada: The nomenclatural debate and systematic ichnology

Research by the authors and colleagues in eastern Canada has uncovered, from both marine and nonmarine strata, a variety of trace fossils that have disputed nomenclature. Such are the problems that, elsewhere, other occurrences of each of these trace fossils has often resulted in assignment to hopodichnus. In several of these cases, assignment has been based on criteria such as stratigraphy, environment, or phylogeny of the producer, although recent ichno‐logical practice has stressed that trace fossils be named exclusively on morphological grounds. Morphological criteria have been utilized in the identification of hopodichnus, for example, the identification of a coffee‐bean‐shaped structure adjoining a bilobate ribbon structure (i.e., a compound specimen), or a one‐dimensional size parameter distinction (i.e., width of less than 5 mm). Unfortunately, such parameters have never been used consistently. Additionally, since compound ichnotaxa are intergradational trace fossils in which one ichnotaxon passes.