Journal of Atmospheric Chemistry - Rapid transport by deep convection is an important mechanism for delivering surface emissions of reactive halocarbons and other trace species to the tropical... 相似文献
Submarine groundwater discharge (SGD) is herein recognized as a significant pathway of material transport from land to the coastal SW Atlantic Ocean and thus, it can be a relevant factor affecting the marine biogeochemical cycles in the region. This paper focuses on the initial measurements of 226Ra, 228Ra and 222Rn made in Patagonia’s coastal zone of Chubut and Santa Cruz provinces (42°S–48°S, Argentina). 226Ra activity ranged from 2.9 to 73.5 dpm 100 L?1, and 228Ra activity ranged from 11.9 to 311.0 dpm 100 L?1 in groundwater wells. The radium activities found in Patagonia’s marine coastal regions and adjacent shelf indicate significant enrichment throughout the coastal waters. Groundwater samples presented the largest 222Rn activity and ranged from 2.66 to 1083 dpm L?1. Conversely, in the coastal marine environment, the 222Rn activity ranged from 1.03 to 6.23 dpm L?1. The Patagonian coastal aquifer showed a larger enrichment in 228Ra than in 226Ra, which is a typical feature for sites where SGD is dominant, probably playing a significant role in the biogeochemistry of these coastal waters. 相似文献
Modelling cumulative impacts of basin-scale coal seam gas (CSG) extraction is challenging due to the long time frames and spatial extent over which impacts occur combined with the need to consider local-scale processes. The computational burden of such models limits the ability to undertake calibration and sensitivity and uncertainty analyses. A framework is presented that integrates recently developed methods and tools to address the computational burdens of an assessment of drawdown impacts associated with rapid CSG development in the Surat Basin, Australia. The null space Monte Carlo method combined with singular value decomposition (SVD)-assisted regularisation was used to analyse the uncertainty of simulated drawdown impacts. The study also describes how the computational burden of assessing local-scale impacts was mitigated by adopting a novel combination of a nested modelling framework which incorporated a model emulator of drawdown in dual-phase flow conditions, and a methodology for representing local faulting. This combination provides a mechanism to support more reliable estimates of regional CSG-related drawdown predictions. The study indicates that uncertainties associated with boundary conditions are reduced significantly when expressing differences between scenarios. The results are analysed and distilled to enable the easy identification of areas where the simulated maximum drawdown impacts could exceed trigger points associated with legislative ‘make good’ requirements; trigger points require that either an adjustment in the development scheme or other measures are implemented to remediate the impact. This report contributes to the currently small body of work that describes modelling and uncertainty analyses of CSG extraction impacts on groundwater. 相似文献
This paper presents the experience of a service-learning course which used community geography to study a proposed research and community center in DeKalb, IL. The center was proposed as a jointly-developed project by the Northern Illinois University and local governmental entities. The original goal of the course was to explore the viability of the proposed project and solicit feedback from the community through traditional engaged planning and public participation. As students began interacting with university and residential communities, it became clear that both communities had input for the center, and found similarities in their experiences and perceptions. While noted divisions in interest groups are known in DeKalb, both communities found themselves surprisingly interested in meaningful discussion to better understand each other through their shared experiences. In response, our theoretical approach shifted to community geography. Students, university employees, and local residents introduced and analyzed questions together as researchers and participants, and developed recommendations to address shared concern. Students then prepared a report advocating for those concerns to submit to university and community leaders. Following the evolution of this project, this paper presents lessons learned and areas for application of community geography as a pedagogical technique, as an important component of geography curriculum, and as a research framework for town-gown relationship inquiry.
From a scientist’s viewpoint a web site is one tool used to conduct research. From an artist’s viewpoint web sites are a form of visual composition. From a developer’s point of view a web site is a type of application. While web sites are a relatively new medium with a particular set of constraints, they do adhere to the same basic design principles that apply to other art forms. These design principles are the basic assumptions that affect the arrangement of elements within a composition. A successful design uses the principles and elements to achieve a visual goal in the composition. A web site designed for scientists has unique properties which are not shared by many other types of web sites. These properties influence the overall visual design of the web sites. Recently at the Institute of Geophysics and Planetary Physics at UCLA undertook a re-design of a number of its websites. In the effort, the use of visual design principles combined with the properties of a science web site were put to the test. In all, six different web sites were designed each with a difference science focus. We describe the process used to design the web sites which involve forming teams of designers, scientists and developers. We present example pages from each design and conclude with a discussion of what was learned during the process. 相似文献