Miracle-dz/UniFAR-FTUs huggingface dataset:
Global NO x , HNO3, PAN, and NO y distributions from fossil fuel combustion emissions: A model study

The 11-level Geophysical Fluid Dynamics Laboratory global chemical transport model (GCTM) which explicitly treats NOx, HNO3, and PAN as transported species has been used to assess the impact of fossil fuel combustion emissions on the distribution of reactive nitrogen compounds (NOy ) in various regions of the troposphere. The GCTM is driven by 6-hour time-averaged wind and total precipitation fields derived from a parent general circulation model. PAN production rates are calculated using background, two-dimensional ethane and propane fields, which are then adjusted to parameterize the effect of short-lived hydrocarbons over continental regions. From an analysis of our model results, we conclude that (1) the model reproduces the observed spatial patterns of wet deposition near the major fossil fuel combustion source regions. Wet and dry deposition in source regions account for 30% and 40–45% of the emissions, respectively, with the remainder being exported over the adjacent ocean basins; (2) the fossil fuel source accounts for a large fraction of the observed surface concentrations and wet deposition fluxes of HNO3 in the extra tropical North Atlantic; (3) while it appears that a significant fraction of NOy observed in the marine free troposphere during the NASA Global Tropical Experiment/CITE 2 experiment in the eastern North Pacific cannot be explained in terms of the fossil fuel source, this may simply indicate that in this region subgrid-scale transport from adjacent continental source regions is not being adequately resolved by the model; (4) at the more remote Mauna Loa, Hawaii site, less than 30% of the observed NOy during May 1988, appears to be due to distant fossil fuel sources; (5) even with the explicit treatment of PAN as a transported species, the fossil fuel source has only a minor impact on NOy, levels in the remote tropics and in the southern hemisphere; (5) model calculations indicate that the relatively high levels of NOy observed over western Alaska during the ABLE 3A experiment in July-August 1988, cannot be explained in terms of long-range transport of fossil fuel combustion emissions from the northern hemisphere mid-latitude surface source regions; and (6) away from source regions, PAN is a major component of fossil fuel NOy, and is the dominant component poleward of 45°N. However, the relative impact of this sequestered PAN on regional spring time NOx levels has yet to be established.
Provenance of the Mesoproterozoic (1.45 Ga) Belt basin (western North America): Another piece in the pre-Rodinia paleogeographic puzzle

The Mesoproterozoic (1.47-1.40 Ga) Belt basin in western North America contains a thick succession of siliciclastic strata dominated by sediment derived from source areas that lay to the west and southwest of the present basin. The age and identity of this source area is important for reconstruction of the Mesoproterozoic history of western North America. Over 400 new SHRIMP U-Pb ages for detrital zircons, supplemented by Ar-Ar ages of detrital muscovite from sandstones within the Belt basin, document distinctive provenances of the basin fill; the predominant sediment influx came from a western craton, whereas subordinate input came from Laurentian sources to the east and south of the basin. During deposition of the lower two-thirds of the Belt basin, the western source was composed predominantly of Proterozoic rocks with 1920-1460 Ma ages; abundant grains have 1610-1500 Ma ages. These latter ages are unrepresentative of Laurentian sources, falling within the North American magmatic gap (1610-1490 Ma), but are widespread in central and eastern Australia and Baltica, the former being the most likely candidate for a former fluvial connection to western North America. The presence of detrital-zircon grains (1480-1440 Ma) with ages contemporary with sedimentation in the Belt basin suggests that the western source area hosted active magmatism during Belt sedimentation. The Missoula Group in the upper Belt records the sedimentologic effects of basin reorganization, which introduced sediment from a new southwestern source that, in contrast to earlier Belt history, resembles crust of the southwestern United States and lacks grains within the North American magmatic gap. Evidence for extension is widespread in the Belt basin in the form of mafic volcanic rocks, rapid rates of sedimentation, and intrabasinal syndepositional faults. The predominant contribution of detrital material from the western source area throughout Belt deposition, in concert with the large-scale facies patterns and evidence for rapid rates of subsidence, is taken to suggest that the Belt basin represents an extensional basin with a tectonically active western side. Although a wholly extensional environment has been suggested by previous workers, we suggest that an alternative model, wherein the Belt basin developed within an extensional domain along a collisional/convergent plate margin, analogous to Tethyan sedimentary basins such as the Black and Caspian Seas, is equally viable and paints a different picture of western North America at ca. 1450 Ma.
Evidence for rapid retreat and mass loss of Thwaites Glacier, West Antarctica

Abstract Thwaites Glacier, the second largest ice stream in West Antarctica, drains an area of 166 500 ± 2000 km2 which accumulates 55 ± 5 Gt a−1 (or 60 ± 6 km3 ice a−1) into the Amundsen Sea, unrestrained by an ice shelf. Using interferometric synthetic-aperture radar (InSAR) data collected by the European Remote-sensing Satellites (ERS-1 and -2) in 1996, an output flux of 71 ±7 Gt a−1 (or 77 ± 8 km3 ice a−1) is estimated at the grounding line, where ice thickness is deduced from hydrostatic equilibrium. A similar flux, 70 ± 7 Gt a−1 (or 76 ± 8 km3 ice a−1), is obtained at a gate located 20 km upstream, where ice thickness was measured in 1978 by ice-sounding radar. Total accumulation in between the two gates is 1.6 Gt a−1, or 1.8 km3 ice a−1. Ice discharge therefore exceeds mass accumulation by 30 ± 15%, and Thwaites Glacier must be thinning and retreating at present. The InSAR data show that the glacier floating ice tongue exerts no back pressure on the inland ice, calves into tabular icebergs along a significant fraction of its grounding line, and has a grounding-line thickness which exceeds a prior-calculated limit for stability. Glacier thinning is confirmed at the coast by the detection of a 1.4 ± 0.2 km retreat of its grounding line between 1992 and 1996 with InSAR, which implies 3.2 ± 0.6 m ice a−1 thinning at the glacier center and less near the sides. These results complement the decimeter-scale annual surface lowering observed with satellite radar altimetry several hundred km inland of the grounding line. The magnitude of ice thinning estimated at the coast, however, rules out temporal changes in accumulation as the explanation for surface lowering. Ice thinning must be due to changes in ice flow.
Modelagem hidrológica chuva-vazão com dados de radar e pluviômetros

A principal informacao de entrada para os modelos chuva-vazao e a precipitacao; uma variavel fundamental do ciclo hidrologico com caracteristicas que dependem de seu tipo. O objetivo desde trabalho e analisar o impacto de diferentes formas de medida da precipitacao em saidas de modelos chuva-vazao. As simulacoes hidrologicas foram realizadas com o modelo IPH II para 3 conjuntos de dados de precipitacao como entrada do modelo: 1) pluviometros, 2) chuva de radar, 3) radar mais pluviometro – chuva analisada. A area escolhida para a realizacao do estudo foi a bacia do rio Barigui, na regiao metropolitanade Curitiba, Parana. Os resultados indicaram que as medidas de pluviometros apresentam bons resultados para eventos de precipitacao estratiforme. Por outro lado, simulacoes para eventos de precipitacao com distribucao espacial irregular nao apresentaram bom desempenho. Alem disso, as simulacoes hidrologicas com precipitacao estimada apenas pelo radar nao apresentaram resultados satisfatorios, ora subestimando ou superestimando a vazao. Os melhores resultados foram produzidos com o campo de precipitacao analisada com a ANOBES.
Optimization of spectral bands for hyperspectral remote sensing of forest vegetation

Optimization principles of accounting for the most informative spectral channels in hyperspectral remote sensing data processing serve to enhance the efficiency of the employed high-productive computers. The problem of pattern recognition of the remotely sensed land surface objects with the accent on the forests is outlined from the point of view of the spectral channels optimization on the processed hyperspectral images. The relevant computational procedures are tested using the images obtained by the produced in Russia hyperspectral camera that was installed on a gyro-stabilized platform to conduct the airborne flight campaigns. The Bayesian classifier is used for the pattern recognition of the forests with different tree species and age. The probabilistically optimal algorithm constructed on the basis of the maximum likelihood principle is described to minimize the probability of misclassification given by this classifier. The classification error is the major category to estimate the accuracy of the applied algorithm by the known holdout cross-validation method. Details of the related techniques are presented. Results are shown of selecting the spectral channels of the camera while processing the images having in mind radiometric distortions that diminish the classification accuracy. The spectral channels are selected of the obtained subclasses extracted from the proposed validation techniques and the confusion matrices are constructed that characterize the age composition of the classified pine species as well as the broad age-class recognition for the pine and birch species with the fully illuminated parts of their crowns.
The nature and origin of Argentine loess

ABSTRACT Though the loess deposits of Argentina (Pampean Formation) are geologically well known, their granulometric and mineralogical composition has hitherto not been analyzed. The data obtained from a study of more than fifty samples are here summarized. It is shown that Argentine loess is similar in field appearance and texture to the North American and European loess. However, the mineralogical composition is completely different, especially in the coarse fractions where an assemblage of volcanic minerals is predominant. The presence of abundant montmorillonite and glass shards in the fine fraction is a point of resemblance between the Argentine and the American sediments. All this material, doubtless of volcanic-pyroclastic origin, has been transported by winds to the place of deposition
Validation of stratospheric nitric acid profiles observed by Improved Limb Atmospheric Spectrometer (ILAS)–II

[1] The Improved Limb Atmospheric Spectrometer-II (ILAS-II) was launched aboard the Advanced Earth Observing Satellite-II (ADEOS-II) in December 2002. Stratospheric vertical profiles of nitric acid (HNO3) concentration observed by ILAS-II (version 1.4) are validated using coincident HNO3 measurements by balloon-borne instruments (MIPAS-B2 and MkIV) in March and April 2003. Further validation is performed by making climatological comparisons of lower stratospheric HNO3-ozone (O3) correlations obtained by ILAS-II and ILAS (the predecessor of ILAS-II) for specific potential vorticity-based equivalent latitudes and seasons where and when ILAS data showed very compact correlations in 1997. The reduced scatter of ILAS-II HNO3 values around the reference HNO3, which is derived from ILAS-II O3 using the ILAS HNO3-O3 correlation, shows that the precision of the ILAS-II HNO3 data is better than 13–14%, 5%, and 1% at 15, 20, and 25 km, respectively. Combining all of the comparisons made in the present study, the accuracy of the ILAS-II HNO3 profiles at 15–25 km is estimated to be better than −13%/+26%.
Redistribution by deep convection and long‐range transport of CO and CH4 emissions from the Amazon basin, as observed by the airborne campaign TROPOZ II during the wet season

Flights performed over South America in the Austral summer, during the airborne campaign Tropospheric Ozone Experiment (TROPOZ II, January 1991), have shown an upper tropospheric maximum (UTM) of carbon monoxide, methane, and relative humidity above 7 km altitude and between 30°S and 5°N. The study of chemical characteristics and convective/transport processes associated with this UTM shows that the air came from the Amazon basin boundary layer, was lifted by convective processes to upper levels, and was then redistributed over South America, and even across the South Atlantic toward the African coast, by the upper level anticyclone present during the wet season over tropical South America. The chemical composition of this UTM (high CO, CH 4 , and relative humidity; medium NOy, NO, and alkanes; low ozone and acetylene) agrees with the observations from the Atmospheric Boundary Layer Expedition ABLE 2B over the Amazon basin during the wet season and supports a biogenic origin for methane and carbon monoxide. The slow (or even absent) photochemical activity associated with this UTM can be explained by the low levels of active hydrocarbons and reactive nitrogen species. The TROPOZ II results complete and extend observations from previous expeditions by demonstrating that large biogenic emissions of ozone precursors from the Amazon basin can enter the upper general circulation during the Austral summer (December-January-February) and, though they do not contribute significantly to the ozone budget over South America, on being exported to the rest of the global circulation they will certainly become involved in the global ozone budget.
Stratosphere-Troposphere Exchange and Its Impact on the Structure of the Lower Stratosphere

Cross tropopause air mass flux plays an important role for the exchange of minor constituents between the troposphere and stratosphere. In general, one can assume net upward air mass fluxes in the tropics and net downward flow in the extratropics. Yet the detailed picture exhibits coexisting up- and downgoing meso-scale flows in the tropopause region probably occurring at all latitudes. This feature of stratosphere-troposphere exchange is particularly addressed in the paper with emphasis on the extratropics. Tropopause depressions like folds and cut-off lows are meso-scale features heavily contributing to downward transport at middle and high latitudes. Statistics derived from global analyses for the period 12/1983 to 11/1991 reveal that folding and cut-off low activity is about twice as strong in the northern hemisphere than in the southern one. A case study ofa folding event over the North Atlantic using a meso-scale meteorological model shows that downward cross-tropopause fluxes are partly compensated by upward fluxes. The ratio of up- and downgoing air mass is about 2:3 during the simulated episode. Note that the upward flux is not a mere return flow. It is expected that this air mass exchange leads to structural and chemical modifications of the lowest stratosphere.
Directivity of slope dynamic response to seismic shaking

A four year‐long accelerometric monitoring of a landslide‐prone slope area in Italy provided evidence of amplifications with systematic directional differences in shaking energy by a factor of 2–3, apparently correlated with the directions of local topographic features. The examination of regional‐scale data revealed similar site response directivity phenomena also on some steep rock slopes not affected by amplification. The spectral properties of the site responses were investigated using HVSR analysis and a new approach based on the multiplication of spectra from several events. The results suggest that such phenomena are caused by a directional redistribution of spectral energy controlled by a combination of interrelated topographic and geologic factors acting in similar directions.
Coherent HF radar backscatter from small-scale irregularities in the dusk sector of the subauroral ionosphere

The Applied Physics Laboratory high-frequency (HF) radar located at Goose Bay, Labrador, observes coherent backscatter from decameter-scale ionospheric plasma density irregularities. Over a period of 5 months centered on winter solstice, the daily activity includes a distinctive feature that appears at dusk and moves in a westerly direction through the radar field of view. The feature typically spans 1 hour in longitude and is observed for 1-1½ hours. In this paper, we give examples and describe the characteristics of this dusk scatter under geomagnetically quiet conditions. We show that it can be readily distinguished from other types of late afternoon/early evening scatter by the extreme equatorward position of its source region and by the low values of its associated radar Doppler velocities (≤ 200 m/s) and spectral widths (≤ 200 m/s). Comparison of the HF radar observations with nearly simultaneous particle precipitation data obtained with the DMSP F6 satellite demonstrates that the source region lies equatorward of the main auroral zone. We argue that the occurrence of dusk scatter is related to the passage through the radar field of view of the area of intersection of the dusk terminator with the mid-latitude trough. It is shown that the plasma drifts in the source region are slow (≤ 150 m/s) and sunward in the inertial reference frame, as described for the poleward portion of the trough in the Spiro et al. [1978] model of trough formation. The narrowness of the Doppler spectra is also consistent with the picture of the trough as a region of slow, uniform plasma drift. The small-scale irregularities responsible for the radar backscatter may be generated by a cascade process from larger-scale (> 100 m) irregularities that are unstable to the action of the gradient drift instability within the evening trough.
Ammonite faunas, OAE and the Pliensbachian–Toarcian boundary (Early Jurassic) in the Apennines

Bilotta, M. , Venturi, F. & Sassaroli, S. 2010: Ammonite faunas, OAE and the Pliensbachian–Toarcian boundary (Early Jurassic) in the Apennines. Lethaia, Vol. 43, pp. 357–380. The critical Jurassic event known as Early Toarcian Oceanic Anoxic Event (OAE) has been the subject of several studies, but its palaeontological characterization is still problematic, and its dating is therefore debated. The rich ammonite faunas of the Mediterranean Tethys (Italy, Greece, Albania, North Africa, southern Spain, etc.) demonstrate that the OAE separates two very different assemblages, resulting from a strong post-OAE biological renewal. Faunas before the anoxic event include many taxa already present in late Pliensbachian (evolute Phylloceratida; Reynesocoeloceratinae, Protogrammoceratinae and Arieticeratinae), whereas after the anoxic event new forms radiated (Nodicoeloceratinae, Harpoceratinae and Hildoceratinae; afterwards also groups as Mercaticeratinae, Phymatoceratidae and Hammatoceratidae). As these assemblages show remarkable differences from their Northwest European equivalents, in the Apennine it is necessary to use a Mediterranean zonation, here formally established. The examined data suggest accurate boundaries for the OAE, which separates our first two Toarcian Zones, corresponding to Tenuicostatum and Serpentinum standard chronozones. Within this context, the Apennine assemblage placed immediately below the anoxic event is an endemic fauna with more than 15 ammonite genera, two of which (Secchianoceras and Petranoceras) are exclusive of the interval in question. Most abundant are Phylloceratidae (Phylloceras, Lavizzaroceras, Calaiceras and Harpophylloceras), Juraphyllitidae (Meneghiniceras) and Lytoceratidae (Lytoceras); Dactylioceratidae (Dactylioceras, Eodactylites and Secchianoceras) and Hildoceratidae are comparatively less numerous, but these latter show the largest taxonomic diversity (Fontanelliceras, Trinacrioceras, Protogrammoceras, Petranoceras, etc.). The description of this fauna improves the knowledge of a poorly understood interval immediately preceding the OAE, thus allowing better correlations in the Mediterranean area. □Ammonites, chronostratigraphy, Early Jurassic, OAE, Tethys.
Lightning: Estimates of the rates of energy dissipation and nitrogen fixation

The nitrogen needed by plants can normally not be directly obtained from the nitrogen present in molecular form in the atmosphere. The reason for this situation is related to the great energy required to break the N-N bond. Only a few organisms, such as algae and certain bacteria, can 'fix' nitrogen. An abiological process for breaking the N-N bond is provided by lightning. The present investigation is concerned with this possibility. It is found that lightning produces approximately 2.6 x 10 to the 9th kg N per year. There are, however, uncertainties, which are mainly related to the energy of a lightning flash.
The Cathedral and the Bazaar: Musings on Linux and Open Source by an Accidental Revolutionary

From the Publisher: The Cathedral and the Bazaar is a must read for anyone who cares about the future of the computer industry or the dynamics of the information economy. Eric Raymond's persuasive manifesto defining the open source revolution has helped propel this collaborative approach to software development into the mainstream. As corporations continue to adopt technologies like Linux, Apache, and Perl, open source is proving to be the competitive advantage in the Internet Age.
Reflectance spectra of 'featureless' materials and the surface mineralogies of M- and E-class asteroids

This study was supported by grants-in-aid of research from the Central Research Fund of the University of Alberta (to D.G.W.S.), from Sigma Xi, The Scientific Research Society and the Geological Society of America 3741-87 (to E.A.C.) and NASA Planetary Geology and Geophysics grant NAGW 642 (to M.J.G.).
Hafnium, neodymium, and strontium isotope and parent‐daughter element systematics in basalts from the plume‐ridge interaction system of the Salas y Gomez Seamount Chain and Easter Microplate

We present a comprehensive data set with Hf, Nd, and Sr isotope ratios and parent‐daughter trace element concentrations in 111 basalts and glasses from seamounts of the western Easter–Salas y Gomez Seamount Chain (ESC), the Easter Microplate (EMP) spreading centers, and the East Pacific Rise (EPR). Sr and Pb radiogenic isotope ratios and related ratios of highly incompatible parent to lesser incompatible daughter elements grade from high values near the Salas y Gomez (SyG) hot spot location to low values 1000 km west. Here the west rift of the EMP is dominated by typical depleted mid‐ocean ridge basalt (MORB). Hf and Nd radiogenic isotope ratios show the opposite gradients, which also reflect the long‐term enriched nature of the hot spot source and mixing of the hot spot with the depleted upper mantle. Gradients of these parameters occur north and south along the EMP boundaries. These observations confirm the plume‐ridge interaction model proposed for this region by Schilling et al. and further characterize the SyG hot spot. The binary mixing relationship evident in the isotope variations of the basalts is somewhat compromised when the trace elements are considered. This complexity can be explained by modification of trace element abundances during the process of partial melting of the two end‐member components (enriched hot spot and depleted upper mantle). In addition, the melting variability is evident in the basalt bulk compositions, which range from tholeiitic (EMP to 108°W) to alkali basalts (108°W to SyG). A single highly correlated data array in Pb‐isotope space and a linear Pb‐Sr isotope relation indicate that the SyG hot spot is homogeneous. The similarity of the Pb isotope ratios of the SyG hot spot to other long‐term high‐U/Pb mantle domains suggests an origin in subduction‐modified altered oceanic crust. The SyG end‐member isotope composition appears to be pervasive in the south central Pacific mantle, evoking a widespread mantle contamination event by the SyG hot spot in the past.