Historical political ecology: On the importance of looking back to move forward     

Diana K. Davis 《Geoforum》2009,40(3):285-286

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Heliospheric Observations of STEREO-Directed Coronal Mass Ejections in 2008?–?2010: Lessons for Future Observations of Earth-Directed CMEs     

N. Lugaz  P. Kintner  C. M?stl  L. K. Jian  C. J. Davis  C. J. Farrugia 《Solar physics》2012,279(2):497-515

We present a study of coronal mass ejections (CMEs) which impacted one of the STEREO spacecraft between January 2008 and early 2010. We focus our study on 20 CMEs which were observed remotely by the Heliospheric Imagers (HIs) onboard the other STEREO spacecraft up to large heliocentric distances. We compare the predictions of the Fixed-?? and Harmonic Mean (HM) fitting methods, which only differ by the assumed geometry of the CME. It is possible to use these techniques to determine from remote-sensing observations the CME direction of propagation, arrival time and final speed which are compared to in-situ measurements. We find evidence that for large viewing angles, the HM fitting method predicts the CME direction better. However, this may be due to the fact that only wide CMEs can be successfully observed when the CME propagates more than 100^° from the observing spacecraft. Overall eight CMEs, originating from behind the limb as seen by one of the STEREO spacecraft can be tracked and their arrival time at the other STEREO spacecraft can be successfully predicted. This includes CMEs, such as the events on 4 December 2009 and 9 April 2010, which were viewed 130^° away from their direction of propagation. Therefore, we predict that some Earth-directed CMEs will be observed by the HIs until early 2013, when the separation between Earth and one of the STEREO spacecraft will be similar to the separation of the two STEREO spacecraft in 2009??C?2010.  相似文献   

Observational Tracking of the 2D Structure of Coronal Mass Ejections Between the Sun and 1 AU     

N. P. Savani  J. A. Davies  C. J. Davis  D. Shiota  A. P. Rouillard  M. J. Owens  K. Kusano  V. Bothmer  S. P. Bamford  C. J. Lintott  A. Smith 《Solar physics》2012,279(2):517-535

The Solar TErrestrial RElations Observatory (STEREO) provides high cadence and high resolution images of the structure and morphology of coronal mass ejections (CMEs) in the inner heliosphere. CME directions and propagation speeds have often been estimated through the use of time-elongation maps obtained from the STEREO Heliospheric Imager (HI) data. Many of these CMEs have been identified by citizen scientists working within the SolarStormWatch project ( www.solarstormwatch.com ) as they work towards providing robust real-time identification of Earth-directed CMEs. The wide field of view of HI allows scientists to directly observe the two-dimensional (2D) structures, while the relative simplicity of time-elongation analysis means that it can be easily applied to many such events, thereby enabling a much deeper understanding of how CMEs evolve between the Sun and the Earth. For events with certain orientations, both the rear and front edges of the CME can be monitored at varying heliocentric distances (R) between the Sun and 1?AU. Here we take four example events with measurable position angle widths and identified by the citizen scientists. These events were chosen for the clarity of their structure within the HI cameras and their long track lengths in the time-elongation maps. We show a linear dependency with R for the growth of the radial width (W) and the 2D aspect ratio (??) of these CMEs, which are measured out to ???0.7?AU. We estimated the radial width from a linear best fit for the average of the four CMEs. We obtained the relationships W=0.14R+0.04 for the width and ??=2.5R+0.86 for the aspect ratio (W and R in units of?AU).  相似文献   

Development and Evaluation of Geostatistical Methods for Non-Euclidean-Based Spatial Covariance Matrices     

Davis  Benjamin J. K.  Curriero  Frank C. 《Mathematical Geosciences》2019,51(6):767-791

Mathematical Geosciences - Customary and routine practice of geostatistical modeling assumes that inter-point distances are a Euclidean metric (i.e., as the crow flies) when characterizing spatial...  相似文献   

Dreading CRISPR: GMOs,Honest Brokers,And Mertonian Transgressions          下载免费PDF全文

Glenn Davis Stone 《Geographical review》2017,107(4):584-591

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Mitigating Risks From Fracking-Related Earthquakes: Assessing State Regulatory Decisions     

Charles Davis  Jonathan M. Fisk 《社会与自然资源》2017,30(8):1009-1025

Public concern about earthquakes linked to wastewater injection from fracking operations is rising. However, few have examined how “induced seismicity” is acted upon by state officials. For some, an incremental response to smaller quakes can be viewed as an acceptable risk policy orientation because of the sizeable economic benefits that accompany drilling activities while others prefer risk mitigation policies (such as the use of “threshold policies”) as a better way to address quake-related problems. To account for state response to induced seismicity impacts, we examine three factors: the emergence of quakes as focusing events, the economic importance of oil and gas to state jobs and revenue, and selected characteristics of earthquakes as a policy issue, i.e., complexity and categorical precedence. Using information drawn from documentary sources, we consider which factors are most helpful in accounting for agency decisions aimed at reducing seismic risks linked to nearby injection wells.  相似文献   

Demonstration held in the geology department of the Anglo-Iranian Oil company,Ltd., at Britannic house,London: Saturday, 3rd December, 1938     

A.G. Davis 《Proceedings of the Geologists' Association. Geologists' Association》1940,51(2):207

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Indigenous Land Management in Peri-Urban Landscapes: An Australian Example     

Rachele S. Wilson  Kerry Jones  Sean Fleischfresser  Bridgette Davis  Genevieve Jones 《社会与自然资源》2018,31(3):335-350

This article examines roles, opportunities, and challenges for Indigenous land management in rapidly developing landscapes through a case study of Bunya Bunya Country Aboriginal Corporation, a not-for-profit organization on the Sunshine Coast, Queensland, Australia. An analysis of data collected through semistructured interviews, participant observation, and analysis of secondary sources reveals that Aboriginal land managers work in a variety of roles to manage issues affecting the local environment and cultural heritage sites. These efforts are challenged by the absence of Native Title and colonial land management policies, which restrict Aboriginal involvement in land management. We conclude that there is a need for alternative pathways to engage with Aboriginal land managers who cannot, or choose not to, proceed with Native Title. Decolonized decision-making tools and sustainable enterprises are viable opportunities that partially address these challenges and could deliver tangible socio-economic and cultural benefits to local Aboriginal and non-Aboriginal people.  相似文献   

Towards the Construction of Climate Change Scenarios   总被引：3，自引：2，他引：1  

John F. B. Mitchell  T. C. Johns  M. Eagles  W. J. Ingram  R. A. Davis 《Climatic change》1999,41(3-4):547-581

Climate impacts assessments need regional scenarios of climate change for a wide range of projected emissions. General circulation models (GCMs) are the most promising approach to providing such information, but as yet there is considerable uncertainty in their regional projections and they are still too costly to run for a large number of emission scenarios. Simpler models have been used to estimate global-mean temperature changes under a range of scenarios. In this paper we investigate whether a fixed pattern from a GCM experiment scaled by global-mean temperature changes from a simple model provides an acceptable estimate of the regional climate change over a range of scenarios. Changes estimated using this approximate approach are evaluated by comparing them with results from ensembles of a coupled ocean-atmosphere model. Five specific emissions scenarios are considered. For increases in greenhouse gases only, the 'error' in annual mean temperature for the cases considered is smaller than the sampling error due to the model's internal variability. The method may break down for scenarios of stabilisation of concentrations, because the patterns change as the model approaches equilibrium. The inclusion of large local perturbations due to sulphate aerosols can lead to significant deviations of the temperature pattern from that obtained using greenhouse gases alone. Combining separate patterns for the responses to greenhouse gases and aerosols may improve the accuracy of approximation. Finally, the accuracy of the scaling approach is more difficult to assess for deriving changes in regional precipitation because many of the regional changes are not statistically significant in the climate change projections considered here. If precipitation changes are only marginally significant in other models, the apparent disagreement between different models may be as much due to sampling error as to genuine differences in model response.  相似文献   

Jan Eduard Harff: 1996 Krumbein Medalist     

John C. Davis 《Mathematical Geology》1999,31(2):245-248

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