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[en] Cosmic-ray neutron sensing: from noise to a well established method for non-invasive soil moisture estimation Cosmic ray neutron sensing (CRNS) has been introduced as a new non-invasive large scale method for soil moisture estimation. It is based on the inverse relationship between natural neutrons created by cosmic-ray and the presence of hydrogen at the land-surface, which is predominantly stored as water in the soil (Zreda et al., 2012). Noteworthy, this effect was well known by physicists with studies dating back more than half a century but it was considered as a noise (Hendrick and Edge, 1966). Only several years later, the use of natural neutron fluxes measured at the ground surface for quantifying soil moisture and snow water equivalent has been presented (Kodama et al., 1979). In these experiments, however, the neutron detector was installed below ground and the signal was strongly related to the hydrogen pools close to the probe. For this reason, this set-up probably did not provide relevant advantages in comparison to other point-scale soil moisture techniques (e.g., TDR) and it was considered for monitoring only extreme snowpack conditions (Morin, et al., 2012). In contrast, Zreda et al. (2012) showed that the signal of a neutron detector installed above-ground is sensitive to soil moisture within a large footprint of hundreds of meters horizontally and a soil depth of several decimeters. In such a way, they put CRNS in a new perspective proving to be a valuable technique to estimate soil moisture at an intermediate scale and showing to be a promising method with a range of applications. Above-ground CRNS method for soil moisture estimation is now used by several research groups all around the world and several national networks have been established. Most of the applications focus on detecting temporal soil moisture dynamics but promising results have been shown also as a rover for covering larger areas, for estimation biomass, water interception and large scale snow observations.
[en] Soil-gas radon time series data has been generated at Dharamshala station for seismic studies in NW Himalayas, India. Compared with the influence of temperature and pressure, radon and rainfall have shown a strong correlation. Decomposition of radon time series into three component series (seasonal, trend, and residual) has been done for further recognizing the authentic anomalous values. The irregular patterns in daily and residual radon data have been associated with earthquake events and rainfall. This monitoring station found to be sensitive to the seismic events within a distance of about 70 km. (author)
[en] This paper proposes a meteorological mechanism for large increases in dose rate based on the findings from a high dose rate event that occurred during rainy season in northern Kyushu, Japan. The gamma-ray energy spectrum obtained by NaI(Tl) scintillation spectrometry confirmed the contribution of short-lived 222Rn decay products, such as 214Pb and 214Bi. The locations of monitoring posts, at which the large increases in dose rate were observed, corresponded to rainfall areas. Infrared satellite images and surface weather charts indicate that the intense precipitation was caused by cumulonimbus clouds along a stationary front, which accompanied a low pressure system. The low pressure system had formed in central China approximately 18 to 36 hours before the high dose rate event. Analyses of the backward trajectory and a long-range atmospheric transport model suggest that the low pressure system raised an air mass containing 222Rn to 1 to 2 km altitude above ground level. Then, the air mass that contained the 222Rn was transported laterally to Japan, as the low pressure system advanced to the east along the stationary front. Thus, the high dose rate event was attributed to the eastward advance of the low pressure system that carried the 222Rn and wet deposition of 222Rn decay products. (author)
[en] The hydrological basins and plots dedicated to agriculture and extensive livestock in the Mexico State present serious problems of land degradation due to the slopes of the land, changes in land use, agricultural practices and deforestation due to clandestine logging, this situation causes the redistribution of the land from the mountain ranges, hillsides and slopes towards the plains and bodies of water so is convenient to estimate the redistribution of 137Cs in the soil of the study plot. This work describes the method to calculate the natural inventory of 137Cs of the reference site without degradation by rain, wind or anthropological activity, the procedure to measure the tracer in the study plot or hydrological basin is presented, emphasising an example of a plot dedicated to the cultivation of corn and cattle grazing in the Mexico State. The half-hectare corn growing plot was divided into four transect s, from which three soil samples were obtained per transect at a depth of 15 cm, obtaining a total of 12 soil samples from the plot. The 137Cs inventory was calculated from the 50 cm deep soil profile of two reference sites. The conversion model was used, obtaining a soil redistribution rate with values of -4.2, -1.9, 5.5 and -13.3 t ha-1 a-1 in each transect, which represent the soil gain in the twelve study sites, because the eroded soils from the hill are transported to the lower part where they accumulated in the plot. (author)
[en] A temperature stepped-combustion method for separating soil organic carbon (SOC) fractions and their 14C ages was developed to investigate SOC fixation and stability in soils. After acid-leaching, SOC was sequentially oxidized, and extracted from three temperature intervals: (1) 25-400 °C, (2) 400-600 °C, and (3) 600-900 °C. The acid-soluble carbon and SOC released below 600 °C are labile components, with relatively younger 14C ages, while the SOC released above 600 °C is stable with older 14C ages. We applied this method in a grassland, maize cropland and forest nursery cropland, to assist in understanding the stability of carbon in soils under different land use conditions. (author)
[en] Ethiopia’s vulnerability to the impacts of climate change is due to social, economic and environmental factors particularly population growth, and high level of reliance on rain-fed agriculture and environmental degradation. GHG emissions are increasing because of unsustainable use of natural resources and other antagonistic environmental effects. The Government initiated the Climate-Resilient Green Economy (CRGE) initiative to reduce such adverse effects of climate change. This initiative is a road map for achieving its ambition of reaching middle income status before 2025. Different priority project ideas were also identified through the National Adaptation Program of Action (NAPA) process which addresses climate change adaptation needs of the country. The projects mainly focus in the areas of human and institutional capacity building, improving natural resource management. One of the priority and critical indicators of progress towards achieving the development goals is access to modern energy services. Though; the country is reach in renewable energy sources; it utilizes small portions of hydro, wind solar, wind and geothermal energies. Hence; the Government is planning to embark nuclear power as an alternative option to enhance the energy mix. In this regard it has taken the first step and signed an agreement with Russia setting out a three-year plan to lay the ground for the construction of a center for nuclear science and technology and a nuclear power plant.
[en] This work investigates the ionic content of the upper 28.73 m of the BR-IC-2 core (88°01'21.3S; 82°04'21.7W) collected during the Chilean-Brazilian Antarctic traverser in the austral summer of 2004/05. The concentrations of the major ions Na+ , K+ , Mg2+, Ca2+, Cl- , NO3 - and SO42- and organic acid H3CSO3 - (methanesulfonate - MS- ) were determined by Ion chromatography. Dating, based on the correlation between Na+ and nssSO42- (non sea salt sulfate) concentrations, the δD isotopic ratio and the identification of volcanic eruption layers (Pinatubo / Cerro Hudson in 1993, Agung in 1965 and possibly Bristol Island in 1936) found an age of 85 years (1918-2003) for the core, with precision of ± 3 years. From this dating, it was possible to establish the mean annual precipitation at this site: 0.15 m eq H2 O. A low contribution of sea salts aerosols and a large crustal and biogenic contribution were found, indicated by the concentrations of nssCa2+ and nssSO42-, respectively. The high value of the Cl- / Na+ ratio (4.96) indicates that factors other than the contribution of sea salt contribute to the concentrations of these ions, such as the input or formation of HCl and the lower depletion of Cl- . The K+ and Mg2+ concentrations, although poorly correlated with other ions, are of marine origin. MS- shows low values for the region and NO3 - has no correlation with other ions, due to complex sources since this ion appears as a secondary aerosol. (author)
[en] Understanding the climatic factors that can affect the formation of sea ice in the Southern Ocean has fundamental importance for global climatological studies, especially for the extratropical region. However, there are limitations to the collection of meteorological data in situ due to logistical difficulties in the installation and periodic maintenance of meteorological stations in Antarctica. In view of this, the technique of remote sensing provides information through satellite imagery and atmospheric reanalysis models to understand the impact of climate change on sea ice. This paper presents the state of the art on the influence of major climatic factors on the formation, location and duration of sea ice in Antarctica with the use of remote sensors and atmospheric reanalysis models.(author)
[en] The 41.82 m deep firn core IC-02 (88°01'21.3''S and 82°04'21.7''W) was drilled in the East Antarctic ice sheet during a Chilean-Brazilian scientific traverse in the Austral summer of 2004/2005. This study aimed to determine the stable water isotopes (δ18O e δD) and the snow annual accumulation annual rate. The core was subsampled in a continuous fusion system and the isotopic content determined by a ring-down resonant cavity laser spectrometry (WS-CRDS, Picarro system). The δ18O series ranges from -50.77 ‰ to -41.40 ‰ (mean -46.39 ± 1.37‰), while the δD ranges from -408.18 ‰ to ‑323.85 ‰ (mean -367.43 ± 12.51‰). The excess of deuterium (d) has an average of 4.36 ± 2.66‰. The core represents 85 ± 3 years of snow accumulation, that is, an average rate of 152 ± 64 mm year-1 in water equivalent. From the 1990s onwards, there was a decrease in the mean annual δD concomitant with an increase in the snow accumulation rate (17% from 1974 to 2003). The increase in this accumulation could be associated with a greater mobilization of drift snow to the deposition site, associated with a greater advection of oceanic air masses coming from the Antarctic seas (Amundsen, Bellingshausen, Weddell and Lazarev). Such interpretation is supported by the increase in the zonal winds velocity, as observed in anomalies fields of geopotential height, zonal wind and temperature at 500 mb in the NCEP / NCAR reanalysis. (author)
[en] A new low-cost L1/L2c receiver board is presented in this short letter, along with its first tests. The main strength of the board is its low price tag (around 200 EUR, in quantities of hundreds) as an effective dual-frequency receiver. The effectiveness of the receiver was at first proven by a pedestrian walk experiment on a closed loop, allowing the evaluation of closure errors. Raw measurements were collected and processed in a real-time scenario through a variometric approach implemented in VADASE software. Epoch-by-epoch velocities were estimated on the basis of dual-frequency phase observations and then the trajectory was reconstructed by numerical integration of the estimated velocities. A horizontal closure error lower than 25 cm was achieved; also, a global assessment of the overall 3D trajectory was carried out, performing a comparison to a standard differential solution with respect to a permanent GNSS station, and standard deviations of the differences between 10 and 20 cm for the 3D components (east, north and up) were achieved. Further, static experiments, both in terms of relative positioning and water vapor monitoring by precise point positioning, confirmed the good performance of the new receiver, with coordinates repeatability of a few millimetres for daily solutions, and estimated water vapor behaviour compatible with local rain events. (paper)