Miracle-dz/UniFAR-FTUs huggingface dataset:
Simulations of the West African monsoon with a superparameterized climate model. Part I: The seasonal cycle

AbstractThe West African monsoon seasonal cycle is simulated with two coupled general circulation models: the Community Climate System Model (CCSM), which uses traditional convective parameterizations, and the “superparameterized” CCSM (SP-CCSM), in which the atmospheric parameterizations have been replaced with an embedded cloud-resolving model. Compared to CCSM, SP-CCSM better represents the magnitude and spatial patterns of summer monsoon precipitation over West Africa. Most importantly, the region of maximum precipitation is shifted from the Gulf of Guinea in CCSM (not realistic) to over the continent in SP-CCSM. SP-CCSM also develops its own biases—namely, excessive rainfall along the Guinean coast in summer. Biases in rainfall from both models are linked to a misrepresentation of the equatorial Atlantic cold tongue. Warm sea surface temperature (SST) biases are linked to westerly trade wind biases and convection within the intertropical convergence zone. Improved SST biases in SP-CCSM are linked to .
Spatial gradients in ecohydrologic properties within a pinyon‐juniper ecosystem

The influence of woody vegetation and biological soil crusts on infiltration capacity is one of the several uncertainties associated with the ecohydrologic effects of woody plant encroachment into arid and semi‐arid land systems. The objective of this study was to quantify the effects of Utah juniper (Juniperus osteosperma) and pinyon pine (Pinus edulis) on subcanopy and intercanopy ecohydrologic properties. We measured soil sorptivity, unsaturated hydraulic conductivity [K(h)], soil water content (SWC), and water repellency along radial line transects from under Juniperus and Pinus trees into the centre of the intercanopy space between trees. In the subcanopy, litter mounds, hydrophobic soils, and roots all appear to contribute to preferential flow to below‐surface soils via wetted patches. For both Juniperus and Pinus, K(h) was significantly lower in the subcanopy than the intercanopy average; however, line transect measurements did not show distinct boundaries in K(h) between the two regions. K(h) increased by eight‐fold across a gradient extending outward from near the edge of the canopy to approximately 2 times the canopy radius (CR). This suggests that the influence of these species on hydrologic properties extends significantly into the intercanopy region. Analysis of biological soil crust cover within the intercanopy showed that beyond the gradient zone, increasing structural development of biological soil crust was associated with increased K(h). Furthermore, these results indicate that the distance from the canopy and direction should be considered in the assessment and modelling of woody plant and biological soil crust influence on infiltration capacity. Copyright © 2008 John Wiley & Sons, Ltd.
Importance of covariance components in inversion analyses of densely sampled observed data: an application to waveform data inversion for seismic source processes

SUMMARY Nominally continuous data in space and/or time is obtained in various observations in geophysics. Due to an enhanced technology of computers, we can now invert such observed data with a very high sampling rate. Densely sampled observed data are usually not completely independent of each other, and so we must take this effect into account. As for seismic waveform data, they have at least temporal correlation due to the effect of inelastic attenuation of the Earth. Taking the data covariance into account, we have developed a method of seismic source inversion and applied it to teleseismicP-wave data of the 2003 Boumerdes-Zemmouri, Algeria earthquake. From the comparison of the final slip distributions inverted with and without the covariance components, we found that the effect of covariance components is crucial for a data set of higher sampling rates (≥5 Hz). If we neglect the covariance components, the inverted results become unstable due to overestimation of the information from observed data. So far, it has been widely believed that we can obtain a finer image of seismic source processes, by inverting waveform data with a higher sampling rate. However, the covariance components of observed data originated from inelastic effect of the Earth give a limitation on the resolution of inverted seismic source models.
Mapping and Portraying Inundation Uncertainty of Bathtub-Type Models

ABSTRACT Schmid, K. ; Hadley, B. , and Waters, K. , 2014. Mapping and portraying inundation uncertainty of bathtub-type models. Data errors are an unavoidable reality in maps of present conditions, but with the prevalence of ease-of-use formats and software these errors are becoming less evident. In earlier maps, the resolution or scale of the information and its presentation on a physical medium (e.g., contours) could inherently convey a level of vagueness that corresponded to the accuracy limitations. Maps of modeled output have additional accuracy considerations, especially if extrapolating future or potential events (e.g., 100-year storm). Sea-level rise (SLR) mapping falls into this category but is also highly dependent on present topographic conditions. SLR and other ecological models use continuous surfaces or digital surface models to generate derived information; however, presentation of the uncertainty information can be difficult or confusing. A technique that conveys uncertainty boundaries for a given confidence level was developed for the National Oceanic and Atmospheric Administration Coastal Services Center's SLR and inundation-visualization tool. The technique and definition of uncertainty levels described herein varies from other common methods, but the use of root-mean-square error (RMSE) to derive the assessment is similar. The technique uses the reported RMSE of both elevation and tidal surface and their relationship to a normal distribution. In this way, user-defined confidence levels can be used to map uncertainty both above and below the deterministic value produced in typical single-surface or bathtub models. The technique is used in this context for SLR and inundation mapping but also has applicability in mapping other phenomena.
Comparison of measured and modeled stratospheric UV/Visible actinic fluxes at large solar zenith angles

Measured and modeled stratospheric filter sensitivity weighted ultraviolet/visible (UV/vis) actinic fluxes—approximating the NO2 photolysis rate coefficients (jNO2)— are compared. The measurements were performed with two calibrated 2π‐actinometers assembled on the azimuth angle‐controlled LPMA/DOAS (Laboratoire de Physique Moléculaire et Applications/Differential Optical Absorption Spectroscopy) gondola during a series of balloon flights. Since the actinometer's spectral sensitivity curve did not exactly match the actinic spectrum of NO2 and the skylight's spectrum shape changes with atmospheric height and solar illumination, only proxies (proxy‐)jNO2 rather than true jNO2 values were monitored during balloon ascents (0–30 km) for solar zenith angle (SZA) 75° < SZA < 86°, and at balloon float altitude during solar occultation (86° < SZA < 95°). The measured direct and diffuse total proxy‐jNO2 values compare excellently with radiative transfer (RT) modeling. That finding allows us to rule out uncertainties in computing UV/vis actinic fluxes as a significant factor in the still insufficient modeling of stratospheric NO2 at large SZAs.
The most recent megalandslides of the Canary Islands: El Golfo debris avalanche and Canary debris flow, west El Hierro Island

Two major landsliding events have been identified west of the island of El Hierro: The El Golfo debris avalanche and the Canary debris flow. These landslides were identified from swath bathymetry, seismic reflection, and TOpographic PArametric Sonar (TOPAS) data obtained in December 1994 during a cruise on board the Spanish R/V Hesperides. The El Golfo debris avalanche originated subaerially on the western flank of the island of El Hierro and has an associated 150 km3 rock debris deposit on the base of slope. The Canary debris flow, which dislocated some 400 km3 of sediment, resulted from a different failure originated between 3200 and 3700 m depth at the base of slope of the island of El Hierro. According to the studied data set, its source area seems to have been covered by the El Golfo debris avalanche deposit. The triggering of the El Golfo debris avalanche (between 136 and 21 ka) is related to tensional stresses on the rift zones of the island. These rift zones control the emplacement and morphology of the landslide scar. In the Canary Islands, a relation between landslide ages and island ages can be established, indicating a link between subsidence history, age of shield phases, and giant landslides.
Relation entre perceptions paysannes de la variabilité climatique et observations climatiques au Sud-Bénin

L’etude a pour objectif d’analyser les perceptions paysannes de la variabilite climatique et leur pertinence par rapport aux observations climatiques. A cet effet, elle a compare des donnees climatiques de 14 stations et des perceptions paysannes de la variabilite climatique recueillies a partir d’une enquete aupres de 201 chefs d’exploitation (CE) agricole repartis sur 67 villages au sud-Benin. L’enquete etait constituee d’entretiens collectifs et individuels, a questionnaires ouverts, semi-ouverts et fermes. Les CE sont davantage marques par la degradation de la qualite des saisons des pluies observee entre 1951-1970 et 1971-1990, en l’occurrence la modification des dates de debut et de fin des saisons des pluies, la recrudescence des sequences seches, la diminution du nombre de jours pluvieux et le deficit pluviometrique, que par la relative recente reprise des precipitations au cours des annees 1990 et 2000 sur la region d’etude. Toutefois, le changement d’echelle, de regionale a locale, reduit sensiblement l’ecart entre les perceptions paysannes et les observations climatiques. Les CE citent egalement la baisse des temperatures et l’augmentation de la frequence des vents violents pendant les saisons pluvieuses. Ces perceptions sont contraires aux observations climatiques et suggerent des investigations plus approfondies pour mieux comprendre ces divergences. Face a la variabilite climatique, les CE ont developpe des mesures d’adaptation qui globalement traduisent leur perception. Ceci ouvre des perspectives pour l’elaboration de strategies d’adaptation avec une forte chance d’attirer l’interet des producteurs.
Silicification: The Processes by Which Organisms Capture and Mineralize Silica

Silicification is widespread in the biological world and occurs in bacteria, single-celled protists, plants, invertebrates and vertebrates. Minerals formed in the biological environment often show unusual physical properties (e.g., strength, degree of hydration) and often have structures that exhibit order on many length scales. The minerals are formed from an environment that is undersaturated with respect to silicon and under conditions of around neutral pH and low temperature ca. 4–40°C. Formation of the mineral may occur intra- or extra-cellularly and specific biochemical locations for mineral deposition that include lipids, proteins and carbohydrates are known. The significance of the cellular machinery cannot be over emphasized and it is with advances in experimental techniques (cell biology and materials characterization) and advances in understanding (including the ability to design laboratory experiments to mimic the biological environment) that much progress has been made in the field in recent years. In most cases the formation of the mineral phase is linked to cellular processes and if we understand this process the knowledge so gained could be used to good effect in designing new materials for biomedical, optical and other applications. The study of living organisms could result in wealth generation/creation. It should be noted that although significant advances have been made in the last ten years, new questions have arisen and there are many areas requiring exploration. This contribution will place emphasis on the systems for which most is known, namely sponges and diatoms, however, it should be borne in mind that many other organisms from single-celled species such as choanoflagellates (Mann et al. 1982) and radiolaria through to higher plants and molluscs such as the limpet (Mann et al. 1986) make use of silica and form species-specific structures that show structural organization on several length scales. Examples of some of the silicified structures observed …
Evaluating annual nitrous oxide fluxes at the ecosystem scale

Evaluation of N2O flux has been one of the most problematic topics in environmental biogeochemistry over the last 10–15 years. Early ideas that we should be able to use the large body of existing research on terrestrial N cycling to predict patterns of N2O flux at the ecosystem scale have been hard to prove due to extreme temporal and spatial variability in flux. The vast majority of the N2O flux measurement and modeling activity that has taken place has been process level and field scale, i.e., measurement, analysis and modeling of hourly and daily fluxes with chambers deployed in field plots. It has been very difficult to establish strong predictive relationships between these hourly and daily fluxes and field‐scale parameters such as temperature, soil moisture, and soil inorganic N concentrations. In this study, we addressed the question of whether we can increase our predictive understanding of N2O fluxes by examining relationships between flux and environmental parameters at larger spatial and temporal scales, i.e., to explore relationships between annual rather than hourly or daily fluxes and ecosystem‐scale variables such as plant community and soil type and annual climate rather than field‐scale variables such as soil moisture and temperature. We addressed this question by examining existing data on annual fluxes from temperate forest, cropland, and rangeland ecosystems, analyzing both multiyear data sets from individual sites as well as cross‐site comparison of single annual flux values from multiple sites. Results suggest that there are indeed coherent patterns in annual N2O flux at the ecosystem scale in forest, cropland, and rangeland ecosystems but that these patterns vary by region and only emerge with continuous (at least daily) flux measurements over multiple years. An ecosystem approach to evaluating N2O fluxes will be useful for regional and global modeling and for computation of national N2O flux inventories for regulatory purposes but only if measurement programs are comprehensive and continuous.
Intercomparison among four flux aircraft at BOREAS in 1994

Four airplanes measured fluxes of momentum, heat, water vapor, and carbon dioxide in 1994, during the intensive field campaigns of the Boreal Ecosystem-Atmosphere Study (BOREAS): the NOAA/ATDD Long-EZ, the NRC Twin Otter, the University of Wyoming King Air, and the NCAR Electra. This paper presents the results of wing-to-wing formation flights comparing the flux measurements from these airplanes. Comparisons of the spectra of wind components, air temperature, water vapor concentration, and carbon dioxide concentration along with the cospectra of these quantities with vertical velocity showed numerous instructive differences. However, among the three airplanes using established techniques, the fluxes and variances of these quantities generally did not differ by more than one would expect, given the separation of the airplanes. Statistics computed from the Long-EZ data, based on a still evolving application of the Global Positioning System, often differed more strongly.
Broad-band near-field ground motion simulations in 3-dimensional scattering media

The heterogeneous nature of Earth’s crust is manifested in the scattering of propagating seismic waves. In recent years, different techniques have been developed to include such phenomenon in broad-band ground-motion calculations, either considering scattering as a semi-stochastic or purely stochastic process. In this study, we simulate broad-band (0–10 Hz) ground motions with a 3-D ﬁnite-difference wave propagation solver using several 3-D media characterized by von Karman correlation functions with different correlation lengths and standard deviation values. Our goal is to investigate scattering characteristics and its inﬂuence on the seismic waveﬁeld at short and intermediate distances from the source in terms of ground motion parameters. We also examine scattering phenomena, related to the loss of radiation pattern and the directivity breakdown. We ﬁrst simulate broad-band ground motions for a point-source characterized by a classic ω 2 spectrum model. Fault ﬁniteness is then introduced by means of a Haskell-type source model presenting both subshear and super-shear rupture speed. Results indicate that scattering plays an important role in ground motion even at short distances from the source, where source effects are thought to be dominating. In particular, peak ground motion parameters can be affected even at relatively low frequencies, implying that earthquake ground-motion simulations should include scattering also for peak ground velocity (PGV) calculations. At the same time, we ﬁnd a gradual loss of the source signature in the 2–5 Hz frequency range, together with a distortion of the Mach cones in case of supershear rupture. For more complex source models and truly heterogeneous Earth, these effects may occur even at lower frequencies. Our simulations suggests that von Karman correlation functions with correlation length between several hundred metres and few kilometres, Hurst exponent around 0.3 and standard deviation in the 5–10 per cent range reproduce the available observations. perhaps
Cloud microphysical and radiative properties for parameterization and satellite monitoring of the indirect effect of aerosol on climate

[1] The spatial variability of the microphysical fields in stratocumulus clouds is documented in this paper with statistics of droplet number concentration, droplet mean volume radius, and liquid water content for eight cases of the second Aerosol Characterization Experiment. Statistics are calculated in five sublayers, from cloud base to cloud top, and they are utilized for deriving estimates of cloud optical thickness and liquid water path, by assuming either random or maximum overlap. The resulting in situ frequency distributions of optical thickness and liquid water path are validated against distributions of these two parameters retrieved from independent remote sensing measurements of cloud radiances. They are also used for testing parameterizations of optical thickness based on liquid water path and either the droplet effective radius or the cloud droplet number concentration. This unique data set of extensive, concomitant, and independent measurements of cloud microphysical and radiative properties is finally used for assessing the detectability of the aerosol indirect effect through examination of the correlation between cloud optical thickness and droplet effective radius. If only cases of comparable values of geometrical thickness are considered, the correlation between optical thickness and effective radius is negative, as anticipated by Twomey [1977]. However, if the most polluted cases are also accounted for, the trend suggests a positive correlation. In fact, the most polluted cloud systems sampled during ACE-2 were slightly drier, hence thinner, than the marine and intermediate cases, hence producing a positive correlation between optical thickness and droplet effective radius. This study demonstrates that the monitoring of the aerosol indirect effect with satellite observations requires an independent retrieval of the liquid water path together with the cloud optical thickness and droplet effective radius.
Does the Agulhas Current amplify global temperatures during super‐interglacials?

Future projections of climate suggest our planet is moving into a ‘super‐interglacial’. Here we report a global synthesis of ice, marine and terrestrial data from a recent palaeoclimate equivalent, the Last Interglacial (ca. 130–116 ka ago). Our analysis suggests global temperatures were on average ∼1.5°C higher than today (relative to the AD 1961–1990 period). Intriguingly, we identify several Indian Ocean Last Interglacial sequences that suggest persistent early warming, consistent with leakage of warm, saline waters from the Agulhas Current into the Atlantic, intensifying meridional ocean circulation and increasing global temperatures. This mechanism may have played a significant positive feedback role during super‐interglacials and could become increasingly important in the future. These results provide an important insight into a future 2°C climate stabilisation scenario. Copyright © 2010 John Wiley & Sons, Ltd.
Terrestrial age measurements using natural thermoluminescence of a drained zone under the fusion crust of Antarctic ordinary chondrites

Abstract— Miono et al. (1990) and Miono and Nakanishi (1994) have proposed that the build‐up of natural thermoluminescence (TL) in a drained layer directly below the meteorite fusion crust can be used to determine terrestrial ages of meteorites in the 40 to 200 ka range. We have measured the natural TL of the drained layer of 15 meteorites. The data indicate that this technique could be used to determine terrestrial ages of meteorites with ages <200 ka, after which TL equilibrium is reached. Comparison of TL build‐up with terrestrial ages for a suite of Antarctic meteorites suggests that the meteorites have been exposed to temperatures of 0 to 5 °C. The close correspondence between natural TL levels and surface exposure TL growth curves suggest that Allan Hills meteorites with ages <200 ka have spent a significant portion of their terrestrial history exposed on the ice surface, rather than being buried in the ice sheet. The technique is, however, sensitive to thermal history; and, for Antarctic meteorites with terrestrial ages <200 ka, natural TL of the drained zone largely reflects exposure on the ice surface.
Increasing the Knowledge on the Management of Cu‐Contaminated Agricultural Soils by Cropping Tomato (Solanum Lycopersicum L.)

This paper increases the knowledge on the potential use of Cu‐contaminated agricultural soils with tomato (Solanum lycopersicum L.). The effect of Cu and its interaction with soil properties on plant biomass production and on the accumulation of this metal in plant tissues were evaluated by conducting biomass assays in four representative Mediterranean agricultural soils contaminated by Cu. Copper toxicity on plant biomass production, evaluated through the effective concentrations of Cu added to soil that reduce the biomass production by 50% (EC50) and by 10% (EC10), was higher in soils having less soil organic matter and clay content and even in soils with favourable properties but having salinity. For the cases in which tomato was collected, Cu concentrations in them were similar for all soils and doses and never exceed the maximum Cu concentration allowed by the Codex Alimentarius Commission Regulation (10 mgCu kg−1 in fresh weight basis). According to our results, tomato could be cropped in Cu‐contaminated Mediterranean agricultural soils when concentrations of Cu determined in them rely between their respective EC50 and EC10, because production and quality of fruits, the latter understood as the Cu concentration in them, would not be compromised. For the soils assayed, these values would range between 32·9 and 1696·5 mg kg−1, depending on soil properties. Because the baseline value considered is similar to those established in other parts of the European Mediterranean region, these results can be used as guidance for this region to establish adequate phytoremediation strategies and prevent land degradation processes. Copyright © 2014 John Wiley & Sons, Ltd.