Miracle-dz/UniFAR-FTUs huggingface dataset:
Characteristics of maximum-value composite images from temporal AVHRR data

Abstract Red and near-infrared satellite data from the Advanced Very High Resolution Radiometer sensor have been processed over several days and combined to produce spatially continuous cloud-free imagery over large areas with sufficient temporal resolution to study green-vegetation dynamics. The technique minimizes cloud contamination, reduces directional reflectance and off-nadir viewing effects, minimizes sun-angle and shadow effects, and minimizes aerosol and water-vapour effects. The improvement is highly dependent on the state of the atmosphere, surface-cover type, and the viewing and illumination geometry of the sun, target and sensor. An example from southern Africa showed an increase of 40 per cent from individual image values to the final composite image. Limitations' associated with the technique are discussed, and recommendations are given to improve this approach
AGGREGATE FORMATION IN CHLORITIC AND SERPENTINITIC ALPINE SOILS

Variations in soil-water and mineralogical composition of clay particles are important factors governing the formation and stabilization of soil aggregates. We evaluated the effects of these factors on aggregate genesis in two soils with different mineralogical compositions. One developed from chlorite-rich schists and the other from serpentinite, but they have similar organic matter and Fe oxides contents. The <2-mm fractions were submitted to one cycle of wetting and drying, producing two classes of newly formed aggregates (2-5 and >5 mm in diameter). The aggregates differed in water stability, with those from serpentinitic soil being more stable. The amounts of water-dispersible clay (WDC) were lower in the more stable aggregates than in the original <2 mm fraction, and the WDC showed more positive electrophoretic mobility values, indicating its stabilization during aggregation. In the aggregates obtained from chlorite-rich soil, the WDC amounts were similar to those of the <2-mm fractions, and the electrophoretic mobility values were more negative. The aggregation and stabilization processes differed in the two soils and were affected by the clay dispersion/flocculation behavior. The variations in aggregate stabilization were therefore attributed to different clay-clay and clay-sand interactions caused by the mineralogical differences in the clay fractions involved. No differences were found when comparing the two size classes of newly formed aggregates from the same soil. This indicates that the same mechanism produced aggregates of a variety of sizes.
On the feasibility of temporally upscaling instantaneous evapotranspiration using weather forecast information

Quantification of land-surface evapotranspiration (ET) is highly significant in water resources management, climate change studies, and numerical weather prediction. The constant reference evaporative fraction method (EFr, the ratio of the actual to reference ET), which assumes that the daily EFr is equal to that at the satellite overpass time, is a scheme that has been widely applied to upscale remotely sensed instantaneous ET to daily ET. To overcome the difficulties encountered in the acquisition of tower-based meteorological variables, this study investigates the feasibility of using publicly available weather forecast information to estimate the daily reference ET using the constant EFr method. A two-source energy balance model is adopted to compute the instantaneous ET using Moderate-Resolution Imaging Spectroradiometer (MODIS) remote-sensing data acquired between January 2011 and October 2012 at the Yucheng Comprehensive Experimental Station in the North China Plain. The results show that the daily maximum and minimum air temperatures from weather forecast information are consistent with the corresponding ground-based measurements, with a bias of 0.8 K and a root mean square error (RMSE) of <2.0 K. The daily global solar radiation and daily wind speed were poorly forecast when compared with the ground-based measurements. Using the meteorological variables from the daily weather forecast information produced a small bias of 0.1 mm day–1 and an RMSE of 0.6 mm day–1 when the estimated daily reference ET was compared with that derived using the ground-based meteorological measurements. When the remotely sensed instantaneous ET and half-hourly reference ET were as accurate as the ground-based measurements, the upscaling method produced the daily ET, using the meteorological variables from the weather forecast information, with a bias of 0.1 mm day–1 and an RMSE of 0.7 mm day–1.
Evaluation of Remolded Shear Strength and Sensitivity of Soft Clay Using Full-Flow Penetrometers

The undrained remolded shear strength of soft clays is of importance in geosystem design, particularly for offshore structures. Common methods to estimate remolded shear strength, such as correlations with cone penetration data, direct measurement with an in situ field vane shear device, and laboratory measurements, produce varied results and can be particularly costly and time consuming. Full-flow penetrometers (T-bar and Ball) provide an alternative rapid method to estimate remolded shear strength and soil sensitivity through remolding soil by repeated cycling of the penetrometer up and down over a given depth interval. The cyclic penetration resistance degradation curve inherently contains information regarding remolded strength and sensitivity. The objective of this paper is to assess the ability of full-flow penetrometers to predict remolded strength and soil sensitivity, and to develop a suite of predictive correlations in which these properties can be estimated in the absence of complementary laboratory or in situ test data. To accomplish this, full-flow penetration profiles and cyclic tests were performed at five well characterized soft clay sites, which together represent the broad range of soils in which the penetrometers will be often used. A previously developed model for the reduction in penetration resistance with cycling is modified to predict the entire degradation curve, including the remolded penetration resistance using only measurements obtained during initial penetrometer penetration and extraction. Using field vane shear strength as the reference measurement, correlations are developed to predict soil sensitivity and remolded shear strength based solely on full-flow penetrometer data, which is particularly useful in site investigation programs where site specific data are not yet available or are sparse. Finally, the usefulness of these relationships is demonstrated by implementing them for two additional soft clay sites.
The Rezé Urban Catchments Database

The database of the Rezé urban catchments includes not only rainfall and flow rates from two small catchments recorded continuously with a time step of l min over a 7‐year period, but also tensiometric, piezometric, and meteorological measurements. This database has been complemented by information on the catchments themselves by means of digitized land use and topographic maps. This database is regularly updated and available to researchers through the Internet file transfer protocol.
The Little Ice Age glacier maximum in Iceland and the North Atlantic Oscillation: evidence from Lambatungnajökull, southeast Iceland

This article examines the link between late Holocene fluctuations of Lambatungnajökull, an outlet glacier of the Vatnajökull ice cap in Iceland, and variations in climate. Geomorphological evidence is used to reconstruct the pattern of glacier fluctuations, while lichenometry and tephrostratigraphy are used to date glacial landforms deposited over the past ˜400 years. Moraines dated using two different lichenometric techniques indicate that the most extensive period of glacier expansion occurred shortly before c. AD 1795, probably during the 1780s. Recession over the last 200 years was punctuated by re‐advances in the 1810s, 1850s, 1870s, 1890s and c. 1920, 1930 and 1965. Lambatungnajökull receded more rapidly in the 1930s and 1940s than at any other time during the last 200 years. The rate and style of glacier retreat since 1930 compare well with other similar‐sized, non‐surging, glaciers in southeast Iceland, suggesting that the terminus fluctuations are climatically driven. Furthermore, the pattern of glacier fluctuations over the 20th century broadly reflects the temperature oscillations recorded at nearby meteorological stations. Much of the climatic variation experienced in southern Iceland, and the glacier fluctuations that result, can be explained by secular changes in the North Atlantic Oscillation (NAO) Advances of Lambatungnajökull generally occur during prolonged periods of negative NAO index. The main implication of this work relates to the exact timing of the Little Ice Age in the Northeast Atlantic. Mounting evidence now suggests that the period between AD 1750 and 1800, rather than the late 19th century, represented the culmination of the Little Ice Age in Iceland.
Basin‐scale geohydrologic drought flow features of riparian aquifers in the Southern Great Plains

Low‐streamflow hydrographs from 22 subbasins in the U.S. Department of Agriculture‐Agricultural Research Service (USDA‐ARS) Washita River Experimental Watershed complex in central Oklahoma were subjected to recession slope analysis; this method, after that of Brutsaert and Nieber [1977], was derived from a Dupuit‐Boussinesq formulation for the groundwater outflows from the adjoining phreatic aquifers. The longtime aquifer response characteristics were generally found to be close to linear, and the short‐time response characteristics were consistent with Boltzmann similarity. Representative values of the resulting basin‐scale effective groundwater parameters were (35 days)−1 for the low‐flow extinction coefficient (i.e., a storage half‐life of 25 days); 0.021 m2 s−1 for the hydraulic diffusivity, Dh; 0.0035 m2s−½ for the hydraulic desorptivity, Deh; 8 × 10−4 ms−1 for the hydraulic conductivity k; and 0.018 for the drainable porosity (or specific yield), ƒ. The variabilities of Dh, Deh, and k from basin to basin could be better represented by the log‐normal than by the normal distribution; ƒ could be described nearly equally well by both. The storage half‐life is moderately and positively correlated with basin size; in the case of k the correlation is negative but weaker. Any scale dependence of Dh, Deh, and ƒ appears to be negligible.
New species of organic-walled dinoflagellate cysts from the Maastrichtian–Danian boundary interval at Ouled Haddou, northern Morocco

Slimani, H. , Louwye, S. & Toufiq, A. , September 2012. New species of organic-walled dinoflagellate cysts from the Maastrichtian–Danian boundary interval at Ouled Haddou, northern Morocco. Alcheringa 36, 341–358. ISSN 0311-5518. Seven new dinoflagellate cyst species and subspecies, previously figured under open nomenclature, from Maastrichtian and Danian deposits of Ouled Haddou (eastern external Rif Chain) in northern Morocco are formally described, and their stratigraphic ranges are clarified. Conosphaeridium lifum sp. nov. and Kenleyia chabaka sp. nov. have fibrous and reticulate wall surfaces, respectively. Oligosphaeridium saghirum sp. nov. is a small cyst with funnel-shaped distal process extremities. Spiniferella cornuta subsp. kacira subsp. nov. and Fibrocysta brevispinosa sp. nov. are distinguishable by their very short processes. Riculacysta chaouka sp. nov. is characterized by its perforate spinose ectophragm. Andalusiella bacita sp. nov. is a small and spindle-shaped cyst with only a single antapical horn.
Chlorophyll concentration mapping with MIVIS data to assess crown discoloration in the Ticino Park oak forest

Airborne hyperspectral remote observations, characterized by high spatial and spectral resolution, allow the estimation of quantitative vegetation variables useful in forest condition assessment. In this research, total chlorophyll (a + b) concentration (C ab), a biochemical variable describing crown discoloration rate, was mapped to assess oak (Quercus robur L.) condition in the Ticino Regional Park. A simulation experiment was conducted to evaluate the error in C ab estimation due to ecological variables (i.e. canopy leaf area index and understorey characteristics) and to sun-sensor configurations when optical indices are used. Canopy reflectance was simulated by means of the PROSPECT leaf radiative transfer model (Jacquemoud and Baret 1990) coupled with the SAILH canopy radiative transfer model, a variation of the SAIL (Scattering by Arbitrarily Inclined Leaves) model modified to include the hot spot effect (Verhoef 1984, Kuusk 1991). The vegetation was modelled as a two layer medium with oak canopy as the top layer and the understorey as the bottom layer. Simulations were performed for varying leaf C ab and canopy Leaf Area Index (LAI) of the top layer, θl (mean leaf inclination angle) and LAI of the bottom layer (LAIu) and sun-sensor geometry. Optical indices were calculated and used in C ab retrieval. Simulations demonstrated that errors in C ab estimation were negligible when MTCI (MERIS Terrestrial Chlorophyll Index) was used, thus indicating that MTCI was the most reliable index in mapping C ab in this forest environment. Empirical models based on optical indices were developed to map C ab from Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) images acquired by an airborne survey on the Park forested area. A regression analysis between C ab concentration measured in leaves sampled in field and optical indices computed from hyperspectral MIVIS data was conducted. The MTCI index showed the highest performances and was therefore used to map C ab concentration of the Ticino Park oak forest. The C ab map was then used to assess crown discoloration level.
Numerical studies of ice flow over subglacial geothermal heat sources at Grímsvötn, Iceland, using Full Stokes equations

[1] The importance of studying geothermal heat sources under glaciers lies in: (1) the potential for jokulhlaups from such sites; (2) the potential for enhanced sliding of ice masses caused by meltwater lubrication of the ice-bedrock interface; and (3) the potential to gain a deeper understanding of the interaction between the geothermal system and the overlying ice. We study the temporal evolution of an elongated depression on the eastern side of the geothermally active Grimsvotn caldera through numerical 2-dimensional forward modeling, solving the full Stokes equation. The 100-150 m deep depression formed gradually between 1998 and 2004. The model results show that heat flux estimates based on depression volume are strongly dependent on the value of the rate factor A in Glen's flow law. If flow of ice into the depression is not taken into account, heat flux underestimates of 15-75% occur, corresponding to rate factors of 10-68 x 10 -16 s -1 kPa -3 . The estimated heat flux at the study site was 260-390 W m -2 , with the best estimate being 280 W m -2 , obtained from the best estimate of A = 23 × 10 -16 s -1 kPa -3 . The total power of the modeled site was 250-300 MW, about one tenth of the total heat output of Grimsvotn. This heat flux is of comparable magnitude to that of other powerful subglacial geothermal areas. Finally, as the maximum modeled strain rates (1 x 10 -7 s -1 ) are within the range of the applicability of Glen's flow law, this suggests that the full Stokes approach should be valid for the study of many subglacial geothermal areas.
Lifetime estimation for a land-fast ice sheet subjected to ocean swell

Abstract It is well known that an incoming ocean swell produces a strain field in a land-fast ice sheet. The attenuation and spectral content of this strain field can be calculated and has been measured. The response of the sea ice to this type of cyclic forcing has also been measured, and in particular we are able to estimate the number of cycles to failure for sea ice loaded at constant amplitude. In this paper we consider the response of the land-fast ice sheet or vast floe to a measured ice-coupled wave field of variable amplitude. We use the Palmgren-Miner cumulative damage law and stress-lifetime curves taken from field experiments to predict the lifetime of the sea-ice sheet as a function of significant wave height and sea-ice brine fraction. Calculations are performed to account for the swell entering a land-fast sea-ice sheet at arbitrary angle, and the influence of c-axis alignment and the presence of pre-existing cracks are discussed.
Measurements of initial potential gradient and particle charges in a Montana summer thunderstorm

An Aerocommander aircraft made three passes through a small isolated thunderstorm on July 19, 1981. These passes were made at a temperature of −5°C and were in conjunction with other aircraft at different altitudes. The Aerocommander was equipped to measure the vertical component of the ambient potential gradient, particle charge, particle size and character, cloud liquid water content, temperature, and vertical velocity. Evidence is presented for the association of charge with ice particles. The development of the potential gradient in relation to movement of these ice particles is discussed. In general, the highest charge densities, of order −0.5 C km−3, were coincident with regions of high graupel concentration and the highest potential gradients, of order −15 kV m−1, were measured below regions with the highest radar reflectivities. Only a small fraction ( ±5 pC), but these were found even at the earliest stages of electrification. The results are compared to concepts derived from recent laboratory experiments on the charge produced during ice particle collisions.
Holocene Record of Gradual, Catastrophic, and Human-Influenced Sedimentation from a Backbarrier Wetland, Northern New Zealand

Abstract An infilled backbarrier wetland located behind a stationary-type coastal bay barrier is used to reconstruct a 6000-year paleo-environmental record that incorporates gradual, catastrophic, and human-influenced sedimentation styles on the New Zealand coast. The record is assembled from a range of proxy indicators (grain size, magnetic susceptibility, organic content, diatoms, and pollen) and is temporally constrained by tephrochronology, radiocarbon dating, and optical dating. Postglacial sea-level rise, volcanism, tsunami, and catchment clearance are all evident in the sediment record, either as artifacts or indirect indicators. Results from optical dating also provide insights into the process of sediment reworking and mixing from multiple sources during tsunami transport. We argue that backbarrier wetlands formed behind stationary-type (aggraded) bay barriers are of greater value (more sensitive) for longer-term paleo-environmental reconstruction than wetlands associated with prograded-type and receded-type barriers, where the sediment record is typically less complete.
Earthworms produce granules of intricately zoned calcite

Earthworms of the family Lumbricidae, which includes many common species, produce and secrete up to millimeter-sized calcite granules, and the intricate fine-scale zoning of their constituent crystals is unique for a biomineral. Granule calcite is produced by crystallization of amorphous calcium carbonate (ACC) that initially precipitates within the earthworm calciferous glands, then forms protogranules by accretion on quartz grain cores. Crystallization of ACC is mediated by migrating fluid films and is largely complete within 24 h of ACC production and before granules leave the earthworm. Variations in the density of defects formed as a byproduct of trace element incorporation during calcite crystal growth have generated zoning that can be resolved by cathodoluminescence imaging at ultraviolet to blue wavelengths and using the novel technique of scanning electron microscope charge contrast imaging. Mapping of calcite crystal orientations by electron backscatter diffraction reveals an approximate radial fabric to the granules that reflects crystal growth from internal nucleation sites toward their margins. The survival within granules of ACC inclusions for months after they enter soils indicates that they crystallize only within the earthworm and in the presence of fluids containing biochemical catalysts. The earthworm probably promotes crystallization of ACC in order to prevent remobilization of the calcium carbonate by dissolution. Calcite granules vividly illustrate the role of transient precursors in biomineralization, but the underlying question of why earthworms produce granules in volumes sufficient to have a measurable impact on soil carbon cycling remains to be answered.
Statistical derivation of fPAR and LAI for irrigated cotton and rice in arid Uzbekistan by combining multi-temporal RapidEye data and ground measurements

Land surface biophysical parameters such as the fraction of photosynthetic active radiation (fPAR) and leaf area index (LAI) are keys for monitoring vegetation dynamics and in particular for biomass and carbon flux simulation. This study aimed at deriving accurate regression equations from the newly available RapidEye satellite sensor to be able to map regional fPAR and LAI which could be used as inputs for crop growth simulations. Therefore, multi-temporal geo- and atmospherically corrected RapidEye scenes were segmented to derive homogeneous patches within the experimental fields. Various vegetation indices (VI) were calculated for each patch focusing on indices that include RapidEye's red edge band and further correlated with in situ measured fPAR and LAI values of cotton and rice. Resulting coefficients of determination ranged from 0.55 to 0.95 depending on the indices analysed, object scale, crop type and regression function type. The general relationships between VI and fPAR were found to be linear. Nonlinear models gave a better fit for VI-LAI relation. VIs derived from the red edge channel did not prove to be generally superior to other VIs.
Orbital imprint on Holocene palaeohydrological variations in west‐central Europe as reflected by lake‐level changes at Cerin (Jura Mountains, eastern France)

This paper presents a lake‐level record for the Holocene at Lake Cerin (Jura Mountains, eastern France). It is based on a range of sedimentological techniques validated in previous studies, with a combination of systematic lithostratigraphic investigations of the infillings accumulated in the lacustrine basin, and sediment analyses of two selected cores. The chronology is based on 10 radiocarbon dates and pollen stratigraphy. On a millennial scale, the Cerin lake‐level record shows three distinct successive phases characterised by higher lake‐level conditions until ca. 9000 cal. a BP, followed by a maximal lowering at ca. 9000–8500 cal. a BP, and a progressive rise until the present. This rise was punctuated by centennial‐scale fluctuations, with major events around 4000, 2800 and after 1500 cal. a BP. Considered on a multimillennial scale, the general pattern of palaeohydrological changes reconstructed at Cerin reflects the impact of orbitally driven summer insolation. This is in agreement with other regional and extra‐regional palaeoclimatic records, although every record shows peculiarities in timing and shape depending on the proxy used for reconstruction. In this general context, centennial to multicentennial oscillations appear to have been second‐order events in comparison with the major influence of the orbital factor. Copyright © 2011 John Wiley & Sons, Ltd.