Sensitivity analysis of a wetland methane emission model based on temperate and arctic wetland sites

Modelling of wetland CH<sub>4</sub> fluxes using wetland soil emission models is used to determine the size of this natural source of CH<sub>4</sub> emission on local to global scale. Most process models of CH<sub>4</sub> formation and soil-atmosphere CH<sub>4</sub> transport processes operate on a plot scale. For large scale emission modelling (regional to global scale) upscaling of this type of model requires thorough analysis of the sensitivity of these models to parameter uncertainty. We applied the GLUE (Generalized Likelihood Uncertainty Analysis) methodology to a well-known CH<sub>4</sub> emission model, the Walter-Heimann model, as implemented in the PEATLAND-VU model. The model is tested using data from two temperate wetland sites and one arctic site. The tests include experiments with different objective functions, which quantify the fit of the model results to the data. <br><br> The results indicate that the model 1) in most cases is capable of estimating CH<sub>4</sub> fluxes better than an estimate based on the data avarage, but does not clearly outcompete a regression model based on local data; 2) is capable of reproducing larger scale (seasonal) temporal variability in the data, but not the small-scale (daily) temporal variability; 3) is not strongly sensitive to soil parameters, 4) is sensitive to parameters determining CH<sub>4</sub> transport and oxidation in vegetation, and the temperature sensitivity of the microbial population. The GLUE method also allowed testing of several smaller modifications of the original model. <br><br> We conclude that upscaling of this plot-based wetland CH<sub>4</sub> emission model is feasible, but considerable improvements of wetland CH<sub>4</sub> modelling will result from improvement of wetland vegetation data

Кубанська музична фольклористика: етапи становлення

On the basis of materials related to the history of the Ukrainians in Kuban (of 1792) the author determines that priests, historians, ethnographers, students of local lore, regents, choirmasters, teachers and poets were at the beginnings of Kuban musical study of folklore. The formation of Kuban musical folklore had 3 stages: concert and representational stage (of 1818), stage of collection (of 1865), transcriptional and publishing stage. Bihday, Kontsevych, Zakharchenko and Koshyts made the most considerable contribution in development of this science. The author of the article gives detailed information about their biographies

Влияние облучения и отжига на термическую стабильность радиационных дефектов в кремнии

Описан отжиг А-центров, дивакансий, А-центров, модифицированных водородом, в n-Si (P ≈ 10^14 см^-3), в отсутствие и при наличии примеси платины, после облучения протонами с энергией 1,8 МэВ. Показано, что энергия активации отжига радиационных дефектов при взаимодействии с водородно-вакансионными дефектами уменьшается с 1,1 до 0,8 эВ при увеличении концентрации платины в кремнии, так как деформационные поля, создаваемые атомами платины, уменьшают энергию переориентации дефектов. Уточнено энергетическое положение в запрещенной зоне кремния донорного уровня А-центра (ЕV + 0,415 эВ) на основании известных данных о положении А-центра, модифицированного атомом углерода (ЕV + 0,38 эВ) или водорода (ЕV + 0,28 эВ).Описано відпал А-центрів, дивакансій, А-центрів, модифікованих воднем, у n-Si (P ≈ 10^14 см^-3), за відсутності та при наявності домішки платини, після опромінення протонами з енергією 1,8 МеВ. Показано, що енергія активації відпалу радіаційних дефектів при взаємодії з воднево-вакансійними дефектами зменшується від 1,1 до 0,8 еВ зі збільшенням концентрації платини в кремнії, оскільки деформаційні поля, які створюються атомами платини, зменшують енергію переорієнтації дефектів. Уточнено енергетичне положення у забороненій зоні кремнію донорного рівня А-центра (ЕV + 0,415 еВ), виходячи із відомих даних щодо положення А-центра, модифікованого атомом вуглецю (ЕV + 0,38 еВ) або водню (ЕV + 0,28 еВ).The annealing of A-centers, divacancies, A-centers modified by hydrogen was described for n-Si (P ≈ 10^14 cm^-3), with and without platinum dopants, after the irradiation by protons with energy 1.8 MeV. It was shown that the activation energy of annealing for radiation defects under their interaction with hydrogen-vacancy defects is decreased from 1.1 to 0.8 eV with the increasing of platinum concentration in silicon, because the deformation fields, creating by platinum atoms, decrease the energy of the defect re-orientation. In the forbidden zone of silicon the energy state for the donor level of A-center (ЕV + 0.415 eV) was specified based on the data about the position of A-center modified by the carbon atom (ЕV + 0.38 eV) or the hydrogen atom (ЕV + 0.28 eV)

Design and construction of the MicroBooNE detector

This paper describes the design and construction of the MicroBooNE liquid argon time projection chamber and associated systems. MicroBooNE is the first phase of the Short Baseline Neutrino program, located at Fermilab, and will utilize the capabilities of liquid argon detectors to examine a rich assortment of physics topics. In this document details of design specifications, assembly procedures, and acceptance tests are reported

The influence of groundwater and land cover change on evapotranspiration in the Amazon Rainforest transition zone

The Amazon rainforest's moisture recycling system provides water for rainfed agriculture, hydroelectric power generation and human consumption, and is, therefore, an important ecosystem service which is hugely important for the Brazilian economy. However, forest conversion to agriculture in the Amazon severally reduces the evapotranspiration (ET) flux, especially over varying groundwater levels. During the dry season, when precipitation is limiting, access to groundwater can help maintain ET rates. This strongly depends on the rooting depth of vegetation and groundwater depth. These effects on ET may lead to lowering atmospheric moisture, and in turn, less moisture available for downstream precipitation. Understanding how land cover changes impact the moisture recycling systems could significantly influence future decision making. The aim of this research is to improve our understanding of the influence of groundwater depth, land use change and their interaction with ET of forest and agricultural land cover. We used one of the most commonly utilised remote sensing data products from MODIS (MOD16 - 8-day ET at 500m resolution) to investigate the temporal and spatial patterns of land cover change and evapotranspiration in the Amazon region from 2002 to 2017. First, we investigated groundwater's influence on the seasonality of ET under "stable" conditions, i.e., over areas that did not undergo land cover change during the study period. We found differences in seasonality as well as differences between deep and shallow groundwater for agricultural land cover types - Rangeland and Cropland. Secondly, we examined periods of land-use transitions where forest has been converted to agriculture in order to investigate the effect of transition on ET. The loss of ET following land cover change was clear although the time until the new land cover's ET reflected that of a "stable" land cover was highly variable. Lastly, areas of forest gain were examined to assess ET of secondary forest and the length of time until recovery of this ecosystem service. This analysis showed that secondary forests take several years until ET reaches "stable" values but it does return to values within the range of those for primary forest. These results suggest that groundwater and land use changes interact in their effect on ET especially in the seasonality and the time to recover

Linking Hydrology and Biogeochemistry to assess the impact of Lateral Nutrient Fluxes

Until recently, it has been challenging to couple hydrological and biogeochemical processes at the watershed scale. We have coupled two models, WTB and MEL, to simulate lateral water and nutrient fluxes and their influence on ecosystem functioning. WTB is a spatially explicit water balance model. Vertical flow was simulated using a capacitance model with lateral flow dependent on head development and the local slope of the confining layer. The Multiple Element Limitation (MEL) model is an ecosystem model, developed to examine limitation in vegetation acclimating to changes in the availability of two resources (carbon and nitrogen). MEL also incorporates the recycling of resources through the soil. In our coupled model, nutrients are treated as inert solutes and are transported vertically as well as laterally using a mixing model. Nutrients moving down the slope are repeatedly taken up, cycled through vegetation and soils, and released back into the soil solution. We are currently identifying the possibilities for incorporating flood dynamics into the model. We evaluated the impact of adding lateral nutrient fluxes to the original MEL model using a virtual experiment. The model (coupled and MEL only) was applied to a small, well defined catchment. After a simulation period of three years, we detect a redistribution of the stock of inorganic N. A larger amount of N is present near the river than at the top of the slopes of the catchment, largely due to lateral fluxes. Comparing the coupled model to the MEL model, we also find large losses of inorganic N in the coupled model due to large vertical fluxes out of the root zone. These vertical out-fluxes cause a smaller N uptake by plants. To detect if Carbon (C) uptake by plants is affected due to the changes in N distribution, the simulation period has to be increased due to a lag time in the optimization of the C:N ratio in plant biomass