Miracle-dz/UniFAR-FTUs huggingface dataset:
The local surface energy balance of the Ecology Glacier, King George Island, Antarctica: measurements and modelling

Meteorological measurements performed during the austral summer of 1990–91 are used to evaluate the surface energy balance and ablation at an elevation of 100 m asl on the Ecology Glacier, which is an outlet glacier of the main ice cap of King George Island, Antarctica. Strong, gusty westerly winds prevail, although occasional south-easterly winds from the Weddell Sea reach the island. Generally, the climate can be characterized as relatively warm and humid with mean summer temperatures well above 0°C. As a result, considerable ablation (0.75 m water equivalent per month) takes place in the lower parts of the Ecology Glacier. The surface energy balance and ablation are calculated using a model with input from meteorological data. In spite of the large amount of cloud (0.83), solar radiation provided most of the energy used for melting (70.3 W m−2). The longwave radiation, sensible heat flux and latent heat flux contributed −9.5, 27.4 and 7.4 W m−2 respectively. Calculations show that a temperature rise of 1°C increases the ablation by almost 15%. This indicates that the ice caps and glaciers currently present on the subantarctic islands and the Antarctic Peninsula may be quite sensitive to climate change.
Heavy metal concentrations and correlations in rain‐fed farm soils of Sifangwu village, central Gansu Province, China

Concentrations of copper (Cu), lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg), arsenic (As), organic carbon (abbreviated to OC) content and pH were measured in rain‐fed farm soils collected in Sifangwu Village which is located central Gansu Province, Northwest China. Concentrations of Cu, Pb, Cd, Hg and As are higher than the background values in grey calcareous soil. Cd concentration exceeds the Threshold of Secondary Environmental Quality Standard for Soil in China by 261 per cent. By bivariate analysis, it was found that OC does not correlate with heavy metal in the village. This is due to the semiarid conditions and agricultural activities. Principal component analysis (PCA) was used to assess the soil data, applying varimax rotation with Kaiser Normalization. The result shows that the data set is defined for three latent components. 1) PC1, which consists of Cu and Cr, and what is characterized as a component subject to strong lithological influence. 2) PC2, dominantly loaded by OC, Pb and Cd, is linked to agricultural influence, i.e. fertilization and cultivation. 3) PC3, the heavy metals Hg and As, in this component are from aerial deposition, thus this PC is named the atmospheric factor. Because PC1 explains 45·026 per cent of total variance, the source of the heavy metal in topsoil in the study area is assumed to be mainly derived from the lithology. Copyright © 2006 John Wiley & Sons, Ltd.
Shrub characterization using terrestrial laser scanning and implications for airborne LiDAR assessment

Sagebrush-steppe ecosystems across the United States Intermountain West are experiencing major structural and functional changes. Scientists and managers need effective technologies to understand such dynamic changes across broad spatial scales. We tested the capacity of terrestrial laser scanning (TLS) to automatically determine structural information of individual shrubs (principally Artemisia tridentata) and shrub canopies in eastern Washington, USA. Because current airborne LiDAR systems have technological constraints that may limit their utility in shrub-dominated ecosystems, we used the TLS data both in their basic form and to simulate high resolution discrete-return airborne LiDAR data with sample densities of 4 and 16 points m−2. Through spatial wavelet analysis we automatically detected the locations of up to 78% of all individual shrubs identified in the field and up to 88% of shrubs with a crown diameter > 1.5 m. Shrub height and canopy cover derived from TLS data were significantly correlated with field measurements (respectively, r2 = 0.94 and 0.51, p < 0.001, α = 0.05). Automated detection of individual shrub crown area using the high resolution simulated airborne LiDAR dataset was also significantly correlated with field measurements (r2 = 0.47, p ≤ 0.01). Our results indicate that TLS data are useful for automatic quantification of shrub structure and provide a glimpse to the utility of the next generation of small-footprint airborne LiDAR instruments in quantifying shrub biophysical parameters across broad areas.
Evapotranspiration estimates using NOAA AVHRR imagery in the Pampa region of Argentina

We used multiple regression analysis to relate evapotranspiration (ET), computed from a water balance technique, to both thermal infrared and normalized difference vegetation index data obtained from the Advanced Very High Resolution Radiometer (AVHRR) sensor on board on the National Oceanic and Atmospheric Administration (NOAA) satellite. This approach, based on only remotely sensed data, provided a reliable estimate of ET over the Pampas, the main agricultural region of Argentina. The relationship between spectral data and ET was more sensitive to the dates than to the sites used to generate the models.
Phosphorus and Nitrogen Dynamics in Streams Associated With Wildfire: a Study of Immediate and Longterm Effects

Stream nutrient data were collected both during a wildfire and over a subsequent five-year period. Sampling was from a series of paired watersheds located within and outside of the wildfire. Phosphorus and nitrogen concentrations increased from 5 to 60 fold over background levels during the first few days of the month-long wildfire with maximum recorded concentrations as high as 135 μg/L soluble reactive phosphorus, 261 μg/L ammonium, and 61 μg/L nitrate. Total phosphorus and total nitrogen during this same time period increased up to 206 μg/L and 349 mμg/L, respectively. Nutrient concentrations declined to background levels ( 40 μg/L soluble reactive phosphorus and >125 μg/L nitrate in impacted streams, concentrations >5 fold over those observed in control streams. In high gradient watersheds, all nutrients were easily transported to the streams with most notable impact during the early years after the fire. In less steep terrain, soluble reactive phosphorus concentrations were significantly higher 3 to 5 years after the fire, which also corresponded to relatively high spring hydrographs. In contrast, nitrogen compounds were observed to be significantly higher in concentration in fire impact streams in the years immediately following the fire. We attribute these differences in the rate of nutrient loads to be the result of the different mobilization mechanisms of phosphorus and nitrogen and the different soil and geomorphic settings of the watersheds drained by the different streams.
North Atlantic versus Southern Ocean contributions to a deglacial surge in deep ocean ventilation

Past glacial-interglacial climate transitions were accompanied by millennial-scale pulses in atmospheric CO2 that are widely thought to have resulted from the release of CO2 via the Southern Ocean. However, direct proxy evidence for a Southern Ocean role in regulating past ocean-atmosphere CO2 exchange is scarce. Here we use combined radiocarbon and neodymium isotope measurements from the last deglaciation to confirm greatly enhanced overturning and/or air-sea exchange rates relative to today, in particular during the Bolling-Allerod warm interval. We show that this deglacial pulse in ocean ventilation was not driven by the North Atlantic overturning alone, and must have involved an increase in the ventilation of southern-sourced deep waters. Our results thus confirm the removal of a physical and/or dynamical barrier to effective air-sea (CO2) exchange in the Southern Ocean during deglaciation, and highlight the Antarctic region as a key locus for global climate/carbon-cycle feedbacks.
Eastern equatorial Pacific cold tongue during the Last Glacial Maximum as seen from alkenone paleothermometry

[1] We present new alkenone-based sea surface temperature (SST) estimates from the eastern equatorial Pacific (EEP) for the last 30 kyr. By combining these new results with recently published records from the region, we reconstruct the spatial pattern of changes in SST during the Last Glacial Maximum (LGM). Alkenone-based SST estimates show a greater glacial cooling in the upwelling environment of the cold tongue than in sites located further north in the equatorial front and eastern Pacific Warm Pool. This result agrees with the paradigm of stronger glacial winds, increased upwelling, steeper zonal thermocline tilt, and stronger advection of cold water in the Peru Current. Furthermore, we investigate possible changes in glacial surface hydrography by using the alkenone-based SST reconstructions to correct planktonic foraminifera δ18O for the temperature effect. After additional correction for the global ice volume effect, the residual changes in seawater δ18O show a clear latitudinal pattern that would be consistent with a southward shift of the Intertropical Convergence Zone. We thus suggest that changes in sea surface salinities could explain contrasting SST reconstructions based on planktonic foraminifera δ18O, which implied a weakening of the cold tongue. The controversial LGM dynamics of the EEP reconstructed by different proxies, i.e., a weakening or a strengthening of the cold tongue, highlight the necessity to better assess the influence of various biases on these proxies.
Science benefits of onboard spacecraft navigation

Primitive bodies (asteroids and comets), which have remained relatively unaltered since their formation, are important targets for scientific missions that seek to understand the evolution of the solar system. Often the first step is to fly by these bodies with robotic spacecraft. The key to maximizing data returns from these flybys is to determine the spacecraft trajectory relative to the target body—in short, navigate the spacecraft—with sufficient accuracy so that the target is guaranteed to be in the instruments' field of view. The most powerful navigation data in these scenarios are images taken by the spacecraft of the target against a known star field (onboard astrometry).
AVALIAÇÃO DA DISSIPAÇÃO NO AMBIENTE DO RATICIDA BRODIFACUM FORMULADO COMO BLOCO PARAFINADO

In the chemical control of rodents in the Sao Paulo city – Brazil, mainly rats, paraffined blocks containing the active ingredient (a.i.) brodifacoum, are put in gutters being subject to the action of the bad weather that could cart alterations in a.i. and transfer to other environments. Aiming to verify those possibilities, experimental systems with paraffined blocks were mounted simulating the field conditions. Also 100 blocks were put at gutters monitored weekly. Three blocks were weekly collected, for 10 weeks, of the systems and of the gutters, and analyzed by high performance liquid chromatography. The obtained data were used for the evaluation of the dissipation of active ingredient. The results pointed the stability of the molecule under real application environmental conditions, because 100% of a.i. was recuperated after exposition of the block. Although, in the experimental systems, about 50% of the blocks unfastened from the fixation wire to the fifth week of exhibition and the recovery of a.i. decreased gradually along the 10 weeks of the study, reaching 50% of the initial concentration.
Mapping the ancient port at the archaeological site of Itanos (Greece) using shallow seismic methods

A shallow seismic survey was carried out at the archaeological site of Itanos, Crete to locate and map the ancient port. The target layer in the area surveyed consists of Permian–Triassic phyllites covered by alluvial deposits. Seismic refraction and reflection experiments were carried out along eight profiles with a total length 580 m.
Initial results of a global circuit model with variable stratospheric and tropospheric aerosols

[1] A new model of the global circuit has been constructed that treats more realistically than previous models the external influences due to varying charged particle fluxes from space, the internal variability due to the transport of radon by atmospheric dynamics, and the varying aerosol populations. An approximate treatment of the effects of explosive volcanic eruptions, that introduce SO2 and H2O into the stratosphere, involves the creation of ultrafine aerosol particles in the downward branch of the Brewer-Dobson circulation from sulfuric acid aerosol particles vaporized in the upward branch. A large increase in stratospheric column resistance occurs at high latitudes, but for much of the time this column resistance is reduced by stratospheric ionizing radiation due to relativistic electron precipitation. Here we present results for the variability of the global circuit due to the variations of the aerosol populations in the stratosphere and troposphere, the variability of the cosmic ray flux, and the geographical and seasonal variability of the near-surface radioactivity. We discuss inferred changes in the circuit parameters associated with climate change, on interannual to Milankovich timescales.
Neotectonic activity of the Skawa River Fault Zone (Outer Carpathians, Poland)

The Skawa River catchment basin in the Outer Western Carpathians of Poland is situated upon morphostructures showing differentiated mobility in the Quaternary. Long profile of river channel reveals the lowest values of concavity index among the Polish Outer Carpathian rivers, pointing to low degree of river profile maturity, particularly in its middle reach coinciding with a zone of abnormally high river bed gradients. The Skawa River valley utilizes in its middle and northern reaches the Skawa River Fault Zone (SRFZ) composed of differently oriented oblique-slip faults, visible on DEM images as well-marked, rectilinear topolinea- ments. The NNW–SSE to N–S faults in the Silesian Nappe were probably reactivated in Late Pleistocene times as normal faults downthrowing their eastern sides, as shown by abnormally high position of the Weichselian Early Glacial straths on the western valley side. Such an episode of neotectonic activity (late Early Glacial times of the Last Glacial stage) has not been recognized so far in the other river valleys of the Polish segments of the Western Outer Carpathians. We conclude that some of the NNW–SSE to N–S trending faults were reactivated as strike-slip faults. This would conform to the present day stress arrangement within the Polish segment of Carpathians. Moreover, deformations of the Pleistocene straths between Osielec in the south and Wadowice–Zator areas in the north appear to indicate both pre-Weichselian and Weichselian reactivation of the Silesian and – to a lesser extent – Magura frontal thrusts. These movements continued also in the Holocene, although to a smaller extent, most probably due to moderately strong and/or strong earthquakes of magnitudes exceeding 5.5–5.7, resulting in clast fracturing within Holocene alluvium, particularly strong on the Silesian frontal thrust, and less intensive on the Carpathian marginal and Magura frontal thrusts, as well as on some faults that belong to the SRFZ. We are convinced that the record of seismically-induced clast fracturing on one of major fault zones in the Outer Carpathians should lead to revision of the hitherto-existing seismic risk assessment of this region, and particularly of the city of Krakow and other urbanized areas, as well as the planned artificial water reservoir at Świnna Poreba.
The role of permafrost soils in the global carbon-cycle on the timescales of centuries to multi-millennia. A modelling study

The cause of the fast rise in atmospheric CO2 concentration seen in ice core data during the last glacial termination is not fully understood. Most studies indicate the deep Southern ocean as a possible source of this carbon released to the atmosphere. In this study, the role of high carbon soils associated with permafrost is considered. We found that changes in summer insolation in high northern latitudes resulted in a permafrost thaw, that then released carbon to the atmosphere, causing the atmospheric CO2 to rise. This mechanism would have been active during all insolation cycles. The extent of ice sheets on the land was found to be a strong controller for the permafrost-carbon response. The deep Southern ocean still had an important role to play for atmospheric CO2 concentrations. The permafrost-carbon mechanism significantly changed the carbon cycle response to climatic changes. It also improved the match between model output and data.
Pollen‐inferred palaeoclimate reconstructions in mountain areas: problems and perspectives

Transfer functions are an efficient tool for the quantitative reconstruction of past climate from low to mid‐elevation pollen sites. However, the application of existing methods to high‐altitude pollen assemblages frequently leads to unrealistic results. In the aim of understanding the causes of these biases, the standard ‘best modern analogue’ method has been applied to two high‐altitude pollen sequences to provide quantitative climate estimates for the Lateglacial and Holocene periods. Both pollen sequences (Laghi dell'Orgials, 2130 m, SW aspect and Lago delle Fate, 2240 m, E aspect) are located in the subalpine belt, on opposing sides of the St. Anna di Vinadio Valley (Italian Maritime Alps). Different results were obtained from the two sequences. The largest differences occurred in palaeotemperature reconstruction, with notable differences in both the values and trends at each site. These biases may be attributed to: (1) a lack of high elevation ‘best modern analogues’ in the database of modern samples; (2) the problem of pollen taxa that have multiple climatic significance; (3) problems related to the complexity of mountainous ecosystems, such as the phenomenon of uphill transport of tree pollen by wind. Possible improvements to the reconstruction process are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
The velocity probability density of upper atmospheric turbulence

In a series of recent papers [Justus, 1966, 1967a, b] some of the properties of turbulence in the 90–110-km region were discussed. This note will present some preliminary findings concerning the velocity probability density function (pdf) of the turbulence in this region. The probability density p(υi) for a turbulent velocity component υi is defined so that p(υi)dvi is the probability of observing a turbulent velocity component with a value between υi and υi + dυi. The function p(υi) may be characterized by the moments μk about the average velocity υ¯i, where the μ's are given by Of particular interest are the standard deviation σ, the skewness α, and the ‘flatness’ β, which are defined by
Panel regression techniques for identifying impacts of anthropogenic landscape change on hydrologic response

Statistical models relating anthropogenic modifications of the watershed landscape to alterations in streamflow are often plagued by heterogeneity in background watershed conditions and coinciding trends in climate that can complicate the interpretation of clear statistical relationships. This study introduces the use of panel regression as a modeling approach that can better accommodate basin heterogeneity and identify more robust signals between anthropogenic impacts on the watershed landscape and hydrologic response. Panel regression techniques pool multidimensional data recorded across individuals (i.e., watersheds) and through time to better characterize within‐ and between‐variability in the hydrologic data set. The separate attribution of variability to both time and space dimensions enables the method to better identify response characteristics that are generalizable across watersheds. This study introduces in detail two broad classes of panel regression models (the fixed effects and random effects models) that may be particularly useful in the context of identifying and quantifying the impact of human‐induced landscape alterations on hydrologic response. The technique is presented in a case study relating watershed urbanization to changes in the annual runoff coefficient for 19 watersheds in the Northeast United States. Comparisons are made against more standard cross‐sectional and time‐based regression analyses. The results show that the estimated relationship between urbanization and the annual runoff coefficient in this region is highly dependent on the dimensions of data examined (space or time) and model structure selected, with the most sophisticated and appropriate model suggesting that no significant relationship can be detected.
Diversity of the marine cyanobacterium Trichodesmium : characterization of the Woods Hole culture collection and quantification of field populations

Abstract : Trichodesmium is a colonial, N2-fixing cyanobacterium found in tropical oceans. Species of Trichodesmium are genetically similar, but several species coexist. In order to coexist, species may occupy different niche spaces through differential utilization of resources and responses to physical characteristics. To investigate niche differentiation in Trichodesmium, I characterized cultured strains of Trichodesmium, identified and enumerated Trichodesmium clades in the field, and investigated P stress and N2 fixation in field populations. Species of Trichodesmium group into two morphologically diverse clades that are coherent with respect to pigment composition: clade I (Trichodesmium erythraeum and Trichodesmium contortum), and clade II (Trichodesmium thiebautii, Trichodesmium tenue, Trichodesmium hildebrandtii, and Trichodesmium pelagicum). I developed a quantitative polymerase chain reaction (qPCR) method to distinguish between these clades and applied it to field populations in the Atlantic and Pacific. Clade II Trichodesmium spp. were more prominent than clade I in the open ocean. Neither clade correlated with nutrients, but clade I had wider temperature and depth distributions than clade II. Trichodesmium populations in the North Atlantic were more P stressed and had higher N2 fixation rates than the Pacific. Unraveling differences among Trichodesmium spp. enables us to understand their coexistence and factors controlling global N2 fixation.
Ocean Wave Dynamics and El Niño

Abstract The response of an ocean general circulation model to specified wind stress is used to understand the role of ocean wave propagation in the evolution of El Nino events in sea surface temperature (SST) in the equatorial Pacific Ocean. In a control experiment the ocean model reproduces observed equatorial Pacific interannual variability in response to forcing by the observed wind stress. The ocean model is then forced with the same wind stress but with the time evolution of the wind stress forcing reversed. An analysis of the anomalies from the annual cycle in these two experiments delineates the parts of the response that are in equilibrium with and out of equilibrium with the wind stress forcing. In the western equatorial Pacific the SST anomalies are in equilibrium with the wind stress anomalies. In the eastern equatorial Pacific the SST anomalies are not in equilibrium with the wind stress anomalies but rather tend toward equilibrium with the upper-ocean beat content anomalies. The experiment d.