Evaluating an Analytical Model to Predict Subsurface LNAPL Distributions and Transmissivity from Current and Historic Fluid Levels in Groundwater Wells: Comparing Results to Numerical Simulations

A recent analytical model predicts free, entrapped, and residual LNAPL saturations and the LNAPL transmissivity in the subsurface from current and historic fluid levels in groundwater wells. As such, the model accounts for effects of fluid level fluctuations in a well. The model was developed to predict LNAPL specific volumes and transmissivities from current fluid level measurements in wells and either recorded historic fluid level fluctuations in wells or estimates. An assumption is made in the model that the predictions are not dependent on whether the historic highest or lowest fluid level elevations in a well occur first. To test the assumption, we conduct two simulations with a modified multiphase flow numerical code TMVOC that incorporates relative permeability‐saturation‐capillary head relations employed in the model. In one simulation, the initial condition is for fluid levels in a well at the historic highest elevations. In the other simulation, the initial condition is for fluid levels in a well at the historic lowest elevations. We change the boundary conditions so both historical conditions occur followed by generating the current condition. Results from the numerical simulations are compared to model predictions and show the assumption in the analytical model is reasonable. The analytical model can be used to develop/refine conceptual site models and for assessing potential LNAPL recovery endpoints, especially on sites with fluctuating fluid levels in wells.     

The influence of sampling design on spatial data quality in a geographic citizen science project

Geographic citizen science has much potential to assist in wildlife research and conservation, but the quality of observation data is a key concern. We examined the effects of sampling design on the quality of spatial data collected for a koala citizen science project in Australia. Data were collected from three samples—volunteers (n = 454), an Internet panel (n = 103), and landowners (n = 35)—to assess spatial data quality, a dimension of citizen science projects rarely considered. The locational accuracy of koala observations among the samples was similar when benchmarked against authoritative data (i.e., an expert‐derived koala distribution model), but there were differences in the quantity of data generated. Fewer koala location data were generated per participant by the Internet panel sample than the volunteer or landowner samples. Spatial preferences for land uses affecting koala conservation were also mapped, with landowners more likely to map locations for residential and tourism development and volunteers less likely. These spatial preferences have the potential to influence the social acceptability of future koala conservation proposals. With careful sampling design, both citizen observations and land use preferences can be included within the same project to augment scientific assessments and identify conservation opportunities and constraints.     

Slow regolith degradation without creep determined by cosmogenic nuclide measurements in Arena Valley, Antarctica

Estimates of regolith degradation in the McMurdo Dry Valleys of Antarctica are currently based on indirect evidence and ancient ashes at or near the soil surface that suggest excellent preservation of surfaces. On the other hand, the existing cosmogenic-nuclide surface exposure ages from many parts of the Dry Valleys are younger than the age of surface deposits inferred from stratigraphic relations. This suggests some combination of surface erosion or past ice cover, both of which would reduce the apparent exposure age. This paper quantifies the regolith degradation and/or past ice cover by measuring ¹⁰Be and ²⁶Al from a landslide deposit that contains 11.3 Ma volcanic ash. The surface sample yields an apparent exposure age of only 0.4 Ma. However, measurements of the subsurface nuclide concentrations show that the deposit has not been shielded by ice, and that the age of the ash does not conflict with the apparent exposure age when slow degradation of the deposit (2 m Ma⁻¹) is taken into account. Soil creep, which is a common degradational process in a wide variety of environments, is non-existent at this field site, which likely reflects the persistent lack of bio- and cryoturbation.     

A Review of Sampling Effects and Response Bias in Internet Participatory Mapping (PPGIS/PGIS/VGI)

Global interest in participatory mapping described as public participation GIS (PPGIS), participatory GIS (PGIS), and volunteered geographic information (VGI) continues to grow, but systematic study of spatial data quality and sampling effects is limited. This article provides a review and meta‐analysis of Internet‐based PPGIS studies conducted during the period 2006–2015 (n=26) to answer the following research questions: (1) How does mapping effort, as a proxy measure for spatial data quality, differ by sampling group? (2) Does the purpose and context of PPGIS influence mapping results? (3) What is the potential for mapping bias through sampling design? (4) Given the results, what should be the focus of future PPGIS research? Mapping effort was highest in sampling groups whose livelihoods were closely related to the purpose of the study, there was greater mapping effort in household sampling groups compared to volunteer groups, and participant domicile had strong effects on mapped results through spatial discounting. The use of online Internet panels provides higher response rates but lower spatial data quality. Future research should focus on increasing sampling response rates, assessing social trade‐offs using alternative spatial weighting schemes, and examining the capacity of the public to select land use alternatives as a complement to traditional expert‐driven planning systems.     

An assessment of the Jenkinson and Collison synoptic classification to a continental mid-latitude location

A weather-type catalogue based on the Jenkinson and Collison method was developed for an area in south-west Russia for the period 1961–2010. Gridded sea level pressure data was obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. The resulting catalogue was analysed for frequency of individual types and groups of weather types to characterise long-term atmospheric circulation in this region. Overall, the most frequent type is anticyclonic (A) (23.3 %) followed by cyclonic (C) (11.9 %); however, there are some key seasonal patterns with westerly circulation being significantly more common in winter than summer. The utility of this synoptic classification is evaluated by modelling daily rainfall amounts. A low level of error is found using a simple model based on the prevailing weather type. Finally, characteristics of the circulation classification are compared to those for the original JC British Isles catalogue and a much more equal distribution of flow types is seen in the former classification.     

Beyond the boundaries: social place in a protected space

Tourism is increasingly promoted worldwide by public and private agencies as a means of achieving sustainable community development. Rare are the economic windfalls that come without social costs, however, and marketing rural communities as tourist 'products' inevitably forces upon their residents a social transfiguration. Yet, concerns about local places have largely been marginalized in the regionalization and commodification of tourist spaces. As a result, important questions remain unanswered. In response, this study uses the cognitive images of visitors and residents of the twin Alaska 'ghost' towns of Kennicott and McCarthy to describe the evolving landscape of tourism in a protected wilderness community. Specifically, it poses two questions. First, how might disparate perceptions of the tourism landscape serve to define the boundaries of 'place' experience for those who live in or visit Kennicott-McCarthy? Second, can this geographic perspective encourage a proactive planning process more cognizant of the effects on – and responsive to the concerns of – the destination community? A preliminary analysis of the results is presented with a focus on tourism as both agent and process in the structure, identity, and meaning of local places, embedded within larger regions and economies.     

The International Radiation Symposium 2016

正1.Overview The 2016 International Radiation Symposium,a joint venture between the IRC(International Radiation Commission)and IAMAS(International Association of Meteorology and Atmospheric Sciences),took place at the University of Auckland from April 16th to 22nd.The wide scope of atmospheric radiation research was apparent,with focuses rang-     

A merine seismic refraction study of the Santa Barbara Channel,California

Seismic data from a 186 km-long refraction profile in the Santa Barbara Channel have been interpreted using several velocity inversion techniques. Data were obtained during two cruises in 1978 and 1979. Seismic arrivals from fifty explosions of between 1 and 300 lbs. of TNT were recorded by two ocean bottom seismometers, four permanent ocean bottom stations (University of Southern California), and much of the United States Geological Survey/California Institute of Technology southern California seismic network. Travel-time inversion gives a V _p of 6.3 km sec^-1 at 7.2 km depth above 7.2 km sec^-1 at 14.4 km depth at the western end of the channel. At the eastern end, solutions suggest three sediment refractors overlying V _p of 6.4 km sec^-1 at 7.3 km depth, above 7.0 km sec^-1 at 11.6 km depth, above mantle arrivals with V _p of 8.3 km sec^-1 at 21.8 km depth. The velocity structure determined by these methods suggests that the channel has a sedimentary fill of from 4 to 7 km and a layer of mafic plus ultramafic rock 14 to 17 km thick. The greatest thicknesses of sediments are restricted to east of Point Conception. The velocity data also suggest that the Franciscan formation may not be present beneath the channel. Rather, the crust here may represent a thickened portion of the Coast Range ophiolite.     

A relation between magnetic field strength and temperature in sunspots

We present Stokes I Zeeman splitting measurements of sunspots using the highly sensitive (g = 3) Fe i line at = 1.5649 m. The splittings are compared with simultaneous intensity measurements in the adjacent continuum. The relation between magnetic field strength and temperature has a characteristic, nonlinear shape in all the spots studied. In the umbra, there is an approximately linear relation between B ² and T _b, consistent with magnetohydrostatic equilibrium in a nearly vertical field. A distinct flattening of the B ² vs T _brelationship in the inner penumbra may be due to changes in the lateral pressure balance as the magnetic field becomes more horizontal; spatially unresolved intensity inhomogeneities may also influence the observed relation.Operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation.     

Stochastic Modeling of Groundwater Extractions over a Data-Sparse Region of Australia

Setting limit on groundwater extractions is important to ensure sustainable groundwater management. Lack of extraction data can affect interpretations of historical pressure changes, predictions of future impacts, accuracy of groundwater model calibration, and identification of sustainable management options. Yet, many groundwater extractions are unmetered. Therefore, there is a need for models that estimate extraction rates and quantify model outputs uncertainties arising due to a lack of data. This paper develops such a model within the Generalized Linear Modeling (GLM) framework, using a case study of stock and domestic (SD) extractions in the Surat Cumulative Management Area, a predominantly cattle farming region in eastern Australia. Various types of extraction observations were used, ranging from metering to analytically-derived estimates. GLMs were developed and applied to estimate the property-level extraction amounts, where observation types were weighted by perceived relative accuracy, and well usage status. The primary variables found to affect property-level extraction rates were: yearly average temperature and rainfall, pasture, property area, and number of active wells; while variables most affecting well usage were well water electrical conductivity, spatial coordinates, and well age. Results were compared with analytical estimates of property-level extraction, illustrating uncertainties and potential biases across 20 hydrogeological units. Spatial patterns of mean extraction rates (and standard deviations) are presented. It is concluded that GLMs are well suited to the problem of extraction rate estimation and uncertainty analysis, and are ideal when model verification is supported by measurement of a random sample of properties.