Practical Incorporation of Multivariate Parameter Uncertainty in Geostatistical Resource Modeling

There is a need to bridge theory and practice for incorporating parameter uncertainty in geostatistical simulation modeling workflows. Simulation workflows are a standard practice in natural resource and recovery modeling, but the incorporation of multivariate parameter uncertainty into those workflows is challenging. However, the objectives can be met without considerable extra effort and programming. The sampling distributions of statistics comprise the core theoretical notion with the addition of the spatial degrees of freedom to account for the redundancy in the spatially correlated data. Prior parameter uncertainty is estimated from multivariate spatial resampling. Simulation-based transfer of prior parameter uncertainty results in posterior distributions which are updated by data conditioning and the model domain extents and configuration. The results are theoretically tractable and practical to achieve, providing realistic assessments of uncertainty by accounting for large-scale parameter uncertainty, which is often the most important component impacting a project. A simulation-based multivariate workflow demonstrates joint modeling of intrinsic shale properties and uncertainty in estimated ultimate recovery in a shale gas project. The multivariate workflow accounts for joint prior parameter uncertainty given the current well locations and results in posterior estimates on global distributions of all modeled properties. This is achieved by transferring the joint prior parameter uncertainty through conditional simulations.     

Chemical composition of waters and the phytoplankton of the lakes within the delta of the Selenga river

Field observations showed that the characteristics of chemical composition of waters and the development of plankton algae in the lakes within the delta of the Selenga river are determined by their flowage. The most open Lake Nekipelovskoe communicates with the Selenga outlets throughout a year, and Lake Zavernyaikha only at the period of an open channel. Lake Semenovskoe and Lake Khlystov Zaton are located in the islands and are isolated from the outlets. According to composition of main ions, the lakes under investigation refer to the hydrocarbonate class, the calcium group. The sum of ions in the water of Lake Nekipelovskoe approaches the one in the Selenga (86?221 mg/dm³), and the highest sums of ions were recorded in the wintertime in the lakes isolated from the outlets (446?743 mg/dm³). The lakes of the delta are characterized by a high trophicity. The maximum concentrations of total phosphorus in Lake Nekipelovskoe and Lake Zavernyaikha were 68 and 122 μg mg/dm³, and in Lake Semenovskoe and Lake Khlystov Zaton ?0.8 and ?0.63 μg mg/dm³, respectively. The most intense development of algae is observed in Lake Zavernyaikha, which is due to the high population of Baikal endemics. Lake Zavernyaikha showed a close negative correlation between the concentration of NO ₃ ^? , mineral phosphorus and phytoplankton biomass; the correlation coefficient was ?0.8 and ?0.63, respectively. The lakes exhibited increased contents readily hydrolysable organic matter, and a decrease in dissolved oxygen concentration in winter; hydrogen sulfide was repeatedly recorded in Lake Khlystov Zaton. The water quality in the lakes during the springtime varies from “quite clean” to “weakly polluted”; at low-water periods, especially in winters, it can drop to the category of “exceedingly dirty”. The water quality of the Selenga can be influenced by the lakes during spring floods when material accumulated during the wintertime is transported to the river outlets and further to Lake Baikal.     

A Place for Geography in the Liberal Arts College?

This study charts the presence of geography at liberal arts colleges and explores the relationship between the liberal arts and the study of geography. The results of this study reveal a paradox: geography embodies many of the ideals of a liberal arts education and yet this study indicates an absence of degree‐granting geography programs at 93% of institutions. Geography thrives, however, at a select group of liberal arts colleges, and these colleges are disproportionately important as the undergraduate origin for doctorate recipients in geography.     

Proton flux and radiation dose from galactic cosmic rays in the lunar regolith and implications for organic synthesis at the poles of the Moon and Mercury

Galactic cosmic rays are a potential energy source to stimulate organic synthesis from simple ices. The recent detection of organic molecules at the polar regions of the Moon by LCROSS (Colaprete, A. et al. [2010]. Science 330, 463–468, http://dx.doi.org/10.1126/science.1186986), and possibly at the poles of Mercury (Paige, D.A. et al. [2013]. Science 339, 300–303, http://dx.doi.org/10.1126/science.1231106), introduces the question of whether the organics were delivered by impact or formed in situ. Laboratory experiments show that high energy particles can cause organic production from simple ices. We use a Monte Carlo particle scattering code (MCNPX) to model and report the flux of GCR protons at the surface of the Moon and report radiation dose rates and absorbed doses at the Moon’s surface and with depth as a result of GCR protons and secondary particles, and apply scaling factors to account for contributions to dose from heavier ions. We compare our results with dose rate measurements by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) experiment on Lunar Reconnaissance Orbiter (Schwadron, N.A. et al. [2012]. J. Geophys. Res. 117, E00H13, http://dx.doi.org/10.1029/2011JE003978) and find them in good agreement, indicating that MCNPX can be confidently applied to studies of radiation dose at and within the surface of the Moon. We use our dose rate calculations to conclude that organic synthesis is plausible well within the age of the lunar polar cold traps, and that organics detected at the poles of the Moon may have been produced in situ. Our dose rate calculations also indicate that galactic cosmic rays can induce organic synthesis within the estimated age of the dark deposits at the pole of Mercury that may contain organics.     

Spread <Emphasis Type="Italic">F</Emphasis> in the Midlatitude Ionosphere According to DPS-4 Ionosonde Data

The results of studying spread F obtained from the DPS-4 ionosonde data at the observatory of the Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (Moscow) are presented. The methodical questions that arise during the study of a spread F phenomenon in the ionosphere are considered; the current results of terrestrial observations are compared with previously published data and the results of sounding onboard an Earth-satellite vehicle. The automated algorithm for estimation of the intensity of frequency spread F, which was developed by the authors and was successfully verified via comparison of the data of the digisonde DPS-4 and the results of manual processing, is described. The algorithm makes it possible to quantify the intensity of spread F in megahertz (the dFs parameter) and in the number of points (0, 1, 2, 3). The strongest spread (3 points) is shown to be most likely around midnight, while the weakest spread (0 points) is highly likely to occur during the daytime. The diurnal distribution of a 1–2 point spread F in the winter indicates the presence of additional maxima at 0300–0600 UT and 1400–1700 UT, which may appear due to the terminator. Despite the large volume of processed data, we can not definitively state that the appearance of spread F depends on the magnetic activity indices Kp, Dst, and AL, although the values of the dFs frequency spread interval strongly increased both at day and night during the magnetic storm of March 17–22, 2015, especially in the phase of storm recovery on March 20–22.     

Modeling of circulation and salinity in Hooghly estuary

The circulation and salinity distribution in the Hooghly Estuary have been studied by developing a two‐dimensional depth‐averaged numerical model for the lower estuary, where the flow is vertically well mixed. This has been coupled with a one‐dimensional model for the upper estuary, where the flow is assumed to be unidirectional and well mixed over the depth and breadth. The Hooghly River receives high freshwater discharge during the monsoon season (June to September), which has significant effect on the salinity distribution in the estuary. The model‐simulated currents, elevations, and salinities are in good agreement with observations during the dry season. However, during the wet season the computed salinities seem to deviate slightly from the observed values.     

Food gardens as important elements of urban agriculture: Spatio-developmental trends and future prospects for urban gardening in Czechia

The main research goals of the article are to explain the historical context of urban food gardens in Czechia, to describe the current spatial pattern of allotment gardens, and to introduce and analyse recent trends in urban gardening. The main method for achieving the first goal was a literature study. For the second goal, geographical mapping and analysis of data relating to the spatial distribution of allotment gardens were used. For the third goal, mapping together with analysis of semi-structured interviews carried out in community gardens in Prague were used. The analysis showed a strong tradition of urban agriculture and urban food gardening activities in Czechia. Both allotment gardens and newly emerged community gardens were concentrated mainly in the biggest cities and in areas with a rich industrial and mining tradition. This finding supports the significance of gardening as an important element of urban agriculture. However, uncertainty regarding land tenure and long-term sustainability were among the greatest obstacles for the future of allotment and community gardens. The authors’ main recommendations are that urban agriculture should be included as primary land use in sustainable planning and there should be broader community involvement in planning and decision-making processes.     

A model of impulsive loop flares revisited

A critical examination of the components of the recent impulsive loop flare model of Takakura is made. It is found that his analysis of the stability of the electron distribution resulting from anomalous heat conduction is in error and electron plasma waves would not be excited. Rather, in the regions where the electron/proton temperature ratioT _e/T _i 10, electrostatic ion-cyclotron waves would be excited and in the regions whereT _e 10, ion-acoustic waves would be excited. Ratios ofT _e/T _i 10 occur only in the late time development behind the conduction fronts. Since the anomalous resistivity due to electrostatic ion-cyclotron waves is fortuitously about 70% of the one used by Takakura, the general development will follow closely the one calculated by him. Because the anomalous resistivity due to ion-acoustic waves is about 95 times the one used by Takakura, the development in the parts of the loop whereT _e/T _i 10 for late times would be altered considerably.Also Guest Worker at NOAA Space Environment Laboratory, Boulder, Colorado, U.S.A.