Miracle-dz/UniFAR-FTUs huggingface dataset:
An objective determination of the polar vortex using Ertel's potential vorticity

We have developed objective criteria for choosing the location of the northern hemisphere polar vortex boundary region and the onset and breakup dates of the vortex. By determining the distribution of Ertel's potential vorticity (Epv) on equivalent latitudes, we define the vortex edge as the location of maximum gradient of Epv constrained by the location of the maximum wind jet calculated along Epv isolines. We define the vortex boundary region to be at the local maximum convex and concave curvature in the Epv distribution surrounding the edge. We have determined that the onset and breakup dates of the vortex on the 450 K isentropic surface occur when the maximum wind speed calculated along Epv isolines rises above and falls below approximately 15.2 m s -1 . We use 1992-1993 as a test case to study the onset and breakup periods, and we find that the increase of polar vortex Epv values is associated with the dominance of the term in the potential vorticity equation involving the movement of air through the surface due to the diabatic circulation. We also find that the decrease is associated with the dominance of the term involving radiatively induced changes in the stability of the atmosphere.
Effects of lunar cumulate mantle overturn and megaregolith on the expansion and contraction history of the Moon

Gravity anomalies derived from recent Gravity Recovery and Interior Laboratory data suggest the presence of early volume expansion of the Moon. The absence of identifiable thrust faults limits the total net contraction that has occurred. These observations provide constraints on the lunar thermal evolution which raise questions for giant impact origin of the Moon. To study the lunar expansion/contraction history, we perform 3‐D thermochemical mantle evolution models, with solidifying core overlain by a layer of ilmenite‐bearing cumulates (IBCs) resulting from mantle overturn after magma ocean solidification. Our models focus on the effects of the overturn‐produced density stratification with a deep heat‐producing element (HPE) distribution and a top insulating megaregolith layer. The deep HPE can cause an early expansion up to 1.5 km radius due to the heating of thedeep mantle. This HPE distribution also reduces the present‐day contraction by ~7 km. Compared to the models without overturn, an end‐member model with a stable IBC‐rich layer on the core‐mantle boundary shows an overall present‐day contraction as small as 1.1 km. The low thermal conductivity of megaregolith also affects the present‐day contraction, reducing it by ~3 km.
Modeling Carbon Dioxide Production and Transport in a Mixed‐Grass Rangeland Soil

The ability to quantify soil–plant–atmosphere water, heat, and gaseous exchange is important for understanding the linkages between terrestrial ecosystems and Earth's climate. We combined a one‐dimensional vertical soil water flow and heat transport algorithm with a soil CO2 production and transport algorithm to study water, heat, and CO2 exchange for vegetated areas in cold climates that are subject to seasonal snow accumulation and soil water freeze–thaw. The model was applied to a semiarid high‐elevation mixed‐grass rangeland near Laramie, WY. Calibration was achieved by optimizing seven parameters describing plant growth respiration, soil profile CO2 production due to roots and microbes, and the depth distribution of roots and microbes using global parameter optimization. Modeling efficiency (ME) for the calibration and validation periods was high for soil temperature (ME = 0.93–0.96) and variable for soil water content (ME = −0.93 to 0.74), soil CO2 concentration (ME = 0.01–0.59), ecosystem respiration (Reco, ME = −0.71 to 0.59), and snow height (ME = 0.09). The calculated annual C budget for 2 yr yielded a gross primary production (GPP) of 92 to 107, an Reco of 183 to 188, and a net ecosystem exchange (NEE) of −81 to −90 g C m−2 yr−1. The NEE values, suggesting that the site served as a significant C source, were deemed unrealistic considering the fact that precipitation for the site was about average for both years. Sensitivity analysis was used to explore the impact of N‐limitation and soil–plant‐respiration parameters on GPP, Reco, and NEE.
Megamullions and mullion structure defining oceanic metamorphic core complexes on the Mid-Atlantic Ridge

In a study of geological and geophysical data from the Mid-Atlantic Ridge, we have identified 17 large, domed edifices (megamullions) that have surfaces corrugated by distinctive mullion structure and that are developed within inside-corner tectonic settings at ends of spreading segments. The edifices have elevated residual gravity anomalies, and limited sampling has recovered gabbros and serpentinites, suggesting that they expose extensive cross sections of the oceanic crust and upper mantle. Oceanic megamullions are comparable to continental metamorphic core complexes in scale and structure, and they may originate by similar processes. The megamullions are interpreted to be rotated footwall blocks of low-angle detachment faults, and they provide the best evidence to date for the common development and longevity (∼1–2 m.y.) of such faults in ocean crust. Prolonged slip on a detachment fault probably occurs when a spreading segment experiences a lengthy phase of relatively amagmatic extension. During these periods it is easier to maintain slip on an existing fault at the segment end than it is to break a new fault in the strong rift-valley lithosphere; slip on the detachment fault probably is facilitated by fault weakening related to deep lithospheric changes in deformation mechanism and mantle serpentinization. At the segment center, minor, episodic magmatism may continue to weaken the axial lithosphere and thus sustain inward jumping of faults. A detachment fault will be terminated when magmatism becomes robust enough to reach the segment end, weaken the axial lithosphere, and promote inward fault jumps there. This mechanism may be generally important in controlling the longevity of normal faults at segment ends and thus in accounting for variable and intermittent development of inside-corner highs.
Buffer Curves of Acid Clays as Affected by the Presence of Ferric Iron and Aluminum 1

Buffer curves of Al- or Fe-montmorillonites and hectorite in 1.0N KCl had appreciably smaller slopes between pH 5 and 8.5 than did curves for corresponding H-clays. Aluminum or ferric hydrous oxide-clay complexes gave buffer curves indicative of almost no exchangeable Al, Fe, or H on permanent-charge sites, but rather showed a regular increase in pH with additions of NaOH. The behavior of the clay-sesquioxide complexes is thought due to the existence, at pH below about 5, of hydroxy-Al or Fe-ions on exchange sites, with the progressive conversion of these to the corresponding hydroxides upon the addition of base. That such a reaction can result in apparent pH-dependent cation-exchange capacity (CEC) was shown by the reasonably good correspondence between CEC's measured at various pH values and the amounts of base necessary to titrate the complexes to those pH's. It is suggested that the pH-dependent CEC's of some soils may be due to the presence of clay-sesquioxide complexes. In other cases, apparent pH-dependent exchange capacity can be “created” during the neutralization of Al- or Fe-clay, through the interaction of positively charged metal ion-hydroxy complexes with exchange sites. Aluminum- or Fe-hydroxy complexes with montmorillonite were not stable upon digestion in dilute salt solutions, but underwent dismutation to produce the corresponding metal ion and hydroxide. While sesquioxide-montmorillonite complexes resembled many acid soils so far as titration behavior and pH-dependent CEC are concerned, the chlorite-like complexes were far less stable than those found in soils.
The xenon isotopic composition of the primordial Martian atmosphere : Contributions from solar and fission components

Previous models of the evolution of the isotopic composition of Xe in the Martian atmosphere have little room for any Xe produced by fission of 244 Pu, although there is a contribution from the decay of shorter-lived 129 I. We find that the previously calculated ratios of I-derived to Pu-derived Xe can only be matched if Mars accreted very early and outgassing of I-derived Xe after atmospheric loss was much stronger than outgassing of Pu-derived Xe. Alternatively, we find that if we assume that primordial Xe on Mars had the isotopic composition of the solar wind, rather than the previously assumed chondritic Xe, a larger contribution from 244 Pu is allowed, and it is much easier to generate models of outgassing and atmospheric loss that match the present atmosphere. Furthermore, the isotopic composition of solar wind Xe matches that of the Chassigny meteorite (widely considered to represent a sample of Martian interior Xe), so it is not necessary to postulate separate sources of Xe for the interior and atmosphere of Mars.
Spatial pattern analyses of post-fire residual stands in the black spruce boreal forest of western Quebec

In this study, we characterised the composition and configuration of post-fire residual habitats belonging to two physiographic zones of the black spruce–moss domain in western Quebec. Thirty-three large fires (2000–52 000 ha) were selected and extracted on classified Landsat satellite imagery. The results show that a minimum of 2% and a maximum of 22% of burned areas escaped fire, with an overall average of 10.4%. The many forest patches that partially or entirely escaped fire formed residual habitats (RHs). It was found that although the area of RHs follows a linear relationship with fire size, their proportion appears relatively constant. Spatial analyses showed that the fires could be separated into two groups depending on the physiographic zones (East-Canadian Shield v. West-Clay Belt Lowlands). Fires in the west zone generate less RHs and appear to be associated with more extreme weather conditions. In most cases there was no association with water or wetlands; in some fires the presence of RHs is associated with the proximity of water bodies. The failure to find an association between RHs and wetlands suggests that this type of environment is part of the fuel. Coniferous woodland with moss appears particularly overrepresented within RHs. Our results suggest that the local and regional physiographic conditions strongly influence the creation of RHs; therefore, it is important to consider those differences when applying ecosystem-based management.
The 1992 summer circulation in the Northeast Water Polynya from acoustic Doppler current profiler measurements

A July–August 1992 snapshot of the circulation in the Northeast Water Polynya located off the coast of Greenland is presented using data collected with an acoustic Doppler current profiler (ADCP) during the cruise of the USCGC Polar Sea. The data reveal anticyclonic circulation with velocity and transport cores aligned with the local topographic trough. Transport through the trough is between 0.5 and 0.9 Sv. The total ADCP measured velocities are generally less than 10 cm s−1, but some regions have velocities larger than 20 cm s−1. The ratio of the average velocity of the upper 100 m to the average velocity below 100 m shows surface layer flows faster by a factor of between 1.2 and 2. This ratio in the ice-free northwest portion of the polynya is smaller (≈1.5) than found over the adjacent continental shelf (≈2.0), indicating smaller vertical shear. The data show northward flow along the coast, supporting the idea that ice carried by this flow is blocked from entering the polynya by a persistent ice wedge to the south that extends from the coast, east over the topographic trough, to a shallow central bank. By blocking ice advecting from the south, the ice wedge enhances the polynya, supporting the idea that the Northeast Water Polynya is a latent heat polynya.
Toxic cyanobacteria in water: a guide to their public health consequences, monitoring and management.

This book describes the present state of knowledge regarding the impact of cyanobacteria on health through the use of water. It considers aspects of risk management and details the information needed for protecting drinking water sources and recreational water bodies from the health hazards caused by cyanobacteria and their toxins. It also outlines the state of knowledge regarding the principal considerations in the design of programmes and studies for monitoring water resources and supplies and describes the approaches and procedures used. The development of this publication was guided by the recommendations of several expert meetings concerning drinking water (Geneva, December 1995; Bad Elster, June 1996) and recreational water (Bad Elster, June 1996; St Helier, May 1997). An expert meeting in Bad Elster, April 1997, critically reviewed the literature concerning the toxicity of cyanotoxins and developed the scope and content of this book. A draft manuscript was reviewed at an editorial meeting in November 1997, and a further draft was reviewed by the working group responsible for updating the Guidelines for Drinkingwater Quality in March 1998.
Sodium and chloride levels in rainfall, mist, streamwater and groundwater at the Plynlimon catchments, mid-Wales: inferences on hydrological and chemical controls

Abstract. Variations in sodium and chloride in atmospheric inputs (rainfall and mist), stream runoff and groundwater stores are documented for the upper Severn River (Afon Hafren and Afon Hore catchments), Plynlimon, mid-Wales. The results show five salient features. Sodium and chloride concentrations are highly variable and highly correlated in rainfall and mist. The sodium-chloride relationship in rainfall has a slope close to the sodium/chloride ratio in sea-water, and an intercept that is not significantly different from zero. This indicates that sea-salt is the dominant source of both sodium and chloride in rainfall, which would be expected given the maritime nature of the metrology. For mist, there is also a straight line with near-zero intercept, but with a slightly higher gradient than the sea-salt ratio, presumably due to small additional sodium inputs from other sources. There is an approximate input-output balance for both sodium and chloride, with the exception of one groundwater well, in which high chemical weathering results in an anomalous high Na/Cl ratio. Thus, atmospheric deposition is the dominant source of both sodium and chloride in groundwater and streamflow. The fluctuations in sodium and chloride concentrations in the streams and groundwaters are strongly damped compared to those in the rain and the mist, reflecting the storage and mixing of waters in the subsurface. On all timescales, from weeks to years, sodium fluctuations are more strongly damped than chloride fluctuations in streamflow. The additional damping of sodium is consistent with ion exchange buffering of sodium in the catchment soils. Sodium and chloride concentrations are linearly correlated in the streams and groundwaters, but the slope is almost universally less than the sea-salt ratio and there is a non-zero intercept. The Na/Cl ratio in streamflow and groundwater is higher than the sea-salt ratio when salinity is low and lower than the sea-salt ratio when salinity is high. This pattern of behaviour is again consistent with ion exchange buffering of sodium in the catchment soils. The core features of this study are two fold. Firstly, sodium and chloride concentrations are highly damped within the streams and groundwaters relative to the atmospheric input. Secondly, streamflow sodium and chloride respond in similar ways across the catchments, except for the added cation exchange damping of the sodium signal. These findings are remarkable given the heterogeneous nature of the catchments and the complexity of the chemical time series signals in the streams. Keywords: Sodium; chloride; rainfall; mist; stream water; groundwater; Plynlimon; Hafren; Hore; Tanllwyth; moorland; Sitka spruce; forest; cation exchange; fractal
The application of ecological theory to the remediation of macroinvertebrate communities impacted by acid mine drainage

1 Literature Review.3 Background.3 Acid mine drainage and its longevity . 4 Effects of acid mine drainage on aquatic macroinvertebrate communities . 5 Remediation of acid mine drainage and the response of aquatic macroinvertebrate communities.12 Factors limiting the successful recovery of aquatic macroinvertebrate communities . 13 Thesis structure . 23 Environmental and spatial determinants of stream macroinvertebrate communities in an acid mine drainage impacted landscape. 25 Introduction.25 Method . 27 Results.32 Discussion . 42 Sources of aquatic insect colonists to remediated streams: the relative importance of macroinvertebrate drift and adult insect flight.49 Introduction.49 Methods.51 Results.58 Discussion . 63 Remediating macroinvertebrate communities in streams post-mining: responses to habitat and organic matter additions . 68 Introduction.68 Methods.70 Results.76 Discussion . 88 Synthesis . 94 Background.94 Key findings from my research.96 Stream remediation plan . 102 Acknowledgements.110 References.112 Appendix 1.143 Appendix 2.147
Large-scale mapping of the riverbanks, mud flats and salt marshes of the Scheldt basin, using airborne imaging spectroscopy and LiDAR

For maintaining the tidal waterways in the Scheldt basin, including the rivers Rupel and Durme and a large part of the Nete catchment, and for ecological monitoring of the mud flats, salt marshes and riverbank vegetation, the Flemish government needs detailed maps of these rivers and their bank structures. These maps indicate not only vegetation types, plant associations and sediment types but also hard structures, such as quays, locks, sluices and roads. Different remote sensing techniques were used to collect the data necessary to produce the required detailed maps. During the months of July and August 2007 an airborne flight campaign took place to collect hyperspectral and LiDAR data of the Scheldt basin and the Nete catchments. These rivers have a total length of about 240 km. The Airborne Imaging Spectrometer for Applications (AISA) Eagle sensor acquired hyperspectral data in 32 spectral bands covering the visible/near-infrared (VIS/NIR) part of the electromagnetic spectrum with a ground resolution of 1 m. A multiple binary classification algorithm based on Fisher's linear discriminant analysis (LDA) was used to map the salt marshes and riverbank vegetation. Ground truth information, that is vegetation and sediment types, together with their geographical locations collected around the time of the flight campaign, was used to train the classifier in the later classification step. Laser scanning was performed using the Riegl LMS-Q560. The LiDAR dataset obtained had a resolution of at least 1 point per m2 and was used to produce a digital elevation model (DEM) that contains all elements of the terrain. From this DEM a digital terrain model (DTM) was derived by applying appropriate filtering techniques. The elevation models were used primarily to derive information on the height, slope and aspect of the banks and dikes, but they also served as expert knowledge in the classification of the mud flats and bank vegetation. Overall, this work illustrates how airborne hyperspectral and LiDAR data can be used to derive highly detailed maps of the sediments, vegetation and hard structures along tidal rivers in large river basins. It also shows how large datasets can be handled in an expert system, in combination with different classification techniques, to produce the required result and accuracy.
A Weather-Type Approach to Analyzing Winter Precipitation in France: Twentieth-Century Trends and the Role of Anthropogenic Forcing

Abstract The relationship between large-scale atmospheric circulation and November–March precipitation over France during the twentieth century is investigated. A long daily MSLP dataset is used to derive daily weather types that are discriminant for precipitation. A linear regression model is then used to relate the November–March-accumulated precipitation amount and the occurrence frequency of the weather types. This simple model shows that an important part of the interannual variability of precipitation is directly linked to large-scale circulation changes. Trends in observed precipitation and precipitation series reconstructed by regression are computed and compared. Spatially coherent trends in November–March precipitation during the second half of the twentieth century are observed, with an increase in the north and a decrease in the south. The spatial pattern of the trends in reconstructed precipitation is very similar to that observed, even if an underestimation of the positive trends in the nort.
Carbon Dioxide Fixation within Mine Wastes of Ultramafic-Hosted Ore Deposits: Examples from the Clinton Creek and Cassiar Chrysotile Deposits, Canada

Carbon dioxide (CO2) is sequestered through the weathering and subsequent mineralization of the chrysotile mine tailings at Clinton Creek, Yukon Territory, and Cassiar, British Columbia, Canada. Accelerated weathering is attributed to a dramatic increase in surface area, which occurs during the milling of ore. We provide a detailed account of the natural process of carbon trapping and storage as it occurs at Clinton Creek and Cassiar, including mineralogy, modes of occurrence, methods of formation for carbonate alteration, light stable isotope geochemistry, and radiocarbon analysis. Powder X-ray diffraction data were used to identify weathering products as the hydrated magnesium carbonate minerals nesquehonite [MgCO3⋅3H2O], dypingite [Mg5(CO3)4 (OH)2⋅5H2O], hydromagnesite [Mg5(CO3)4(OH)2⋅4H2O], and less commonly lansfordite [MgCO3⋅5H2O]. Textural relationships suggest that carbonate precipitates formed in situ after milling and deposition of tailings. Samples of efflorescent nesquehonite are characterized by δ13C values between 6.52 and 14.36 per mil, δ18O values between 20.93 and 26.62 per mil, and F14C values (fraction of modern carbon) between 1.072 and 1.114, values which are consistent with temperature-dependent fractionation of modern atmospheric CO2 during mineralization. Samples of dypingite ± hydromagnesite collected from within 0.2 m of the tailings surface give δ13C values between ‐1.51 and +10.02 per mil, δ18O values between +17.53 and +28.40 per mil, and F14C values between 1.026 and 1.146, which suggests precipitation from modern atmospheric CO2 in a soil-like environment. Field observations and isotopic data suggest that hydrated magnesium carbonate minerals formed in two environments. Nesquehonite formed in an evaporative environment on the surface of tailings piles, and dypingite and hydromagnesite formed in the subsurface environment with characteristics similar to soil carbonate. In both cases, these minerals
Landscape evolution in Martian mid-latitude regions: insights from analogous periglacial landforms in Svalbard

Abstract Periglacial landforms on Spitsbergen (Svalbard, Norway) are morphologically similar to landforms on Mars that are probably related to the past and/or present existence of ice at or near the surface. Many of these landforms, such as gullies, debris-flow fans, polygonal terrain, fractured mounds and rock-glacier-like features, are observed in close spatial proximity in mid-latitude craters on Mars. On Svalbard, analogous landforms occur in strikingly similar proximity, which makes them useful study cases to infer the spatial and chronological evolution of Martian cold-climate surface processes. The analysis of the morphological inventory of analogous landforms on Svalbard and Mars allows the processes operating on Mars to be constrained. Different qualitative scenarios of landscape evolution on Mars help to better understand the action of periglacial processes on Mars in the recent past.