A shallow subsurface controlled release facility in Bozeman, Montana, USA, for testing near surface CO2 detection techniques and transport models   总被引：1，自引：0，他引：1  

Lee H. Spangler  Laura M. Dobeck  Kevin S. Repasky  Amin R. Nehrir  Seth D. Humphries  Jamie L. Barr  Charlie J. Keith  Joseph A. Shaw  Joshua H. Rouse  Alfred B. Cunningham  Sally M. Benson  Curtis M. Oldenburg  Jennifer L. Lewicki  Arthur W. Wells  J. Rodney Diehl  Brian R. Strazisar  Julianna E. Fessenden  Thom A. Rahn  James E. Amonette  Jon L. Barr  William L. Pickles  James D. Jacobson  Eli A. Silver  Erin J. Male  Henry W. Rauch  Kadie S. Gullickson  Robert Trautz  Yousif Kharaka  Jens Birkholzer  Lucien Wielopolski 《Environmental Earth Sciences》2010,60(2):227-239

A controlled field pilot has been developed in Bozeman, Montana, USA, to study near surface CO₂ transport and detection technologies. A slotted horizontal well divided into six zones was installed in the shallow subsurface. The scale and CO₂ release rates were chosen to be relevant to developing monitoring strategies for geological carbon storage. The field site was characterized before injection, and CO₂ transport and concentrations in saturated soil and the vadose zone were modeled. Controlled releases of CO₂ from the horizontal well were performed in the summers of 2007 and 2008, and collaborators from six national labs, three universities, and the U.S. Geological Survey investigated movement of CO₂ through the soil, water, plants, and air with a wide range of near surface detection techniques. An overview of these results will be presented.  相似文献   

Ensemble-based Kalman filters in strongly nonlinear dynamics   总被引：1，自引：1，他引：0  

Zhaoxia PU  Joshua HACKER 《大气科学进展》2009,26(3):373-380

This study examines the effectiveness of ensemble Kalman filters in data assimilation with the strongly nonlinear dynamics of the Lorenz-63 model, and in particular their use in predicting the regime transition that occurs when the model jumps from one basin of attraction to the other. Four configurations of the ensemble-based Kalman filtering data assimilation techniques, including the ensemble Kalman filter, ensemble adjustment Kalman filter, ensemble square root filter and ensemble transform Kalman filter, are evaluated with their ability in predicting the regime transition (also called phase transition) and also are compared in terms of their sensitivity to both observational and sampling errors. The sensitivity of each ensemble-based filter to the size of the ensemble is also examined.  相似文献   

A northwest North American training set: distribution of freshwater midges in relation to air temperature and lake depth     

Erin M. Barley  Ian R. Walker  Joshua Kurek  Les C. Cwynar  Rolf W. Mathewes  Konrad Gajewski  Bruce P. Finney 《Journal of Paleolimnology》2006,36(3):295-314

Freshwater midges, consisting of Chironomidae, Chaoboridae and Ceratopogonidae, were assessed as a biological proxy for palaeoclimate in eastern Beringia. The northwest North American training set consists of midge assemblages and data for 17 environmental variables collected from 145 lakes in Alaska, British Columbia, Yukon, Northwest Territories, and the Canadian Arctic Islands. Canonical correspondence analyses (CCA) revealed that mean July air temperature, lake depth, arctic tundra vegetation, alpine tundra vegetation, pH, dissolved organic carbon, lichen woodland vegetation and surface area contributed significantly to explaining midge distribution. Weighted averaging partial least squares (WA-PLS) was used to develop midge inference models for mean July air temperature (r _boot² = 0.818, RMSEP = 1.46°C), and transformed depth (ln (x+1); r _boot² = 0.38, and RMSEP = 0.58).  相似文献   

Structures of Mesocirculations Producing Tornadoes Associated with Tropical Cyclone Frances (1998)     

Gandikota V. Rao  Joshua W. Scheck  Roger Edwards  Joseph T. Schaefer 《Pure and Applied Geophysics》2005,162(8-9):1627-1641

Radar structures of one mesocyclone and one mesocirculation (the term mesocirculation refers to a class of rotating updrafts, which may or may not be as spatially and temporally large as a typical mesocyclone) that developed a total of four tornadoes in association with Tropical Cyclone (TC) Frances 1998 are presented. One tornado developed within an inner rainband near the time of landfall while three of the other tornadoes developed within an outer rainband nearly 24 hours after the landfall. Radar reflectivities of the tornadic circulations averaged upwards of 40 dBZ while Doppler radar wind components directed toward the radar averaged 11 m s−1. It is realized that although TC Frances was a minimal hurricane it spawned several tornadoes (four of which were studied) causing damage exceeding $2 million. These tornadoes were not all located close to the TC center, serving as a caution to forecasters and emergency personnel that the immediate landfalling area is not the only place to watch.While it is difficult to accurately predict the TC tornado location and time of occurrence, the degree of low-level baroclinicity seems to play an important role in tornadogenesis. Another significant finding is that the tornadoes were produced on the inward side of an inner rainband, as well as the inward side of an outer rainband. Consistent with climatology, the forward right quadrant of the TC developed the four tornadoes studied here.The lead author, Professor G. V. Rao died 31 July 2004 at the age of 70. He fell victime to the waves while swimming in Mazatlan, Mexico. This is the last paper he publilshed as lead author.  相似文献   

Systematic variation of bedrock channel gradients in the central Oregon Coast Range: implications for rock uplift and shallow landsliding     

Jeremiah S. Kobor  Joshua J. Roering 《Geomorphology》2004,62(3-4):239-256

In tectonically active regions, bedrock channels play a critical role in dictating the pace of landscape evolution. Models of fluvial incision into bedrock provide a means of investigating relationships between gradients of bedrock channels and patterns of active deformation. Variations in lithology, orographic precipitation, sediment supply, and erosional processes serve to complicate tectonic inferences derived from morphologic data, yet most tectonically active landscapes are characterized by these complexities. In contrast, the central Oregon Coast Range (OCR), which is situated above the Cascadia subduction zone, has experienced rock uplift for several million years, did not experience Pleistocene glaciation, boasts a relatively uniform lithology, and exhibits minor variations in precipitation. Although numerous process-based geomorphic studies suggest that rates of erosion across the OCR are relatively constant, it has not been demonstrated that bedrock channel gradients in the region exhibit spatially consistent values. Analysis of broadly distributed, small drainage basins (5–20 km) in the central OCR enables us to explore regional variability in bedrock channel gradients resulting from differential rock uplift or other sources. Consistent with previous studies that have documented local structural control of deformed fluvial terraces in the western portion of our study area, our data reveal a roughly 20-km-wide band of systematically elevated channel slopes (roughly twice the background value), roughly coincident with the strike of N–S-trending mapped folds. Although many factors could feasibly generate this pattern, including variable rock strength, precipitation gradients, or temporal or spatial variations in forearc deformation, the elevated bedrock channel slopes likely reflect differential rock uplift related to activity of local structures. Importantly, our analysis suggests that rock uplift and erosion rates may vary systematically across the OCR. Although our calculations were focused on the fluvial-dominated portion of study basins, our results have implications for upstream areas, including unchanneled valleys that often serve as source areas for long-runout debris flows. Zero-order basins (or topographic hollows) within the N–S-trending band of elevated channel slopes tend to be steeper than adjacent areas and may experience more frequent evacuation by shallow landsliding. Thus, this region of the OCR may be highly sensitive to land use practices and high-intensity rainstorms.  相似文献   

Simultaneous multispectral imaging of the discrete aurora     

Joshua Semeter  Dirk Lummerzheim  Gerhard Haerendel 《Journal of Atmospheric and Solar》2001,63(18)

A unique multispectral imager and an associated multispectral analysis framework are described which together constitute a new diagnostic tool for auroral research. By acquiring spatial and spectral data simultaneously, multispectral imaging allows one to exploit physical connections between auroral morphology and the auroral optical spectrum in a way that sequential spectral imaging cannot. The initial research focus is on imaging the transition in the incident energy spectrum during the formation of discrete arcs—that is, when the precipitating population is characterized by <1 keV electrons. A technique is presented which uses two spectral bands (centered at 4278 and 7325 Å) to extend the effective dynamic range of passive imaging to much lower energies.  相似文献   

The Political Life of Urban Streetscapes: Naming,Politics, and Place. Edited by Reuben Rose‐Redwood,Derek Alderman,and Maoz Azaryahu. xxii and 334 pp.: maps,ills. bibliog. index. Abingdon,U.K.: Routledge, 2018. $140.00 (hardcover), isbn 9781472475091.          下载免费PDF全文

Joshua Hagen 《Geographical review》2018,108(4):634-636

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From berries to blocks: carbon stock quantification of a California vineyard     

Jorge Andres Morandé  Christine M. Stockert  Garrett C. Liles  John N. Williams  David R. Smart  Joshua H. Viers 《Carbon balance and management》2017,12(1):5

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Diagnostics of solar flare hard X-ray sources     

Peter Hoyng  Joshua W. Knight  Daniel S. Spicer 《Solar physics》1978,58(1):139-148

The dynamics of hard X-ray producing electron beams in solar flares can be strongly affected by the occurrence of a reverse current. The parameter diagram for a beam can be divided into three regimes, one of which is the usual thick target case, the two others being due to two different possible consequences of the reverse current. The use of this parameter diagram as a possible diagnostic tool for solar flare hard X-ray sources is discussed, together with the necessary observations and their interpretation.The forthcoming Solar Maximum Mission, complemented with concurrent ground-based efforts provide the next possibility to obtain these observations, given a good coordination of observing programs. We stress the importance of microwave (GHz) ratio observations with good temporal (few sec) and spatial resolution (1) in one dimension, and of reliable spectroscopic methods to determine the density in solar flare hard X-ray sources.  相似文献   

Multilateral parametric climate risk insurance: a tool to facilitate agreement about deployment of solar geoengineering?     

Joshua B. Horton  David W. Keith 《Climate Policy》2019,19(7):820-826

States will disagree about deployment of solar geoengineering, technologies that would reflect a small portion of incoming sunlight to reduce risks of climate change, and most disagreements will be grounded in conflicting interests. States that object to deployment will have many options to oppose it, so states favouring deployment will have a powerful incentive to meet their objections. Objections rooted in opposition to the anticipated unequal consequences of deployment may be met through compensation, yet climate policy is inhospitable to compensation via liability. We propose that multilateral parametric climate risk insurance might be a useful tool to facilitate agreement on solar geoengineering deployment. With parametric insurance, predetermined payouts are triggered when climate indices deviate from set ranges. We suggest that states favouring deployment could underwrite reduced-rate parametric climate insurance. This mechanism would be particularly suited to resolving disagreements based on divergent judgments about the outcomes of proposed implementation. This would be especially relevant in cases where disagreements are rooted in varying levels of trust in climate model predictions of solar geoengineering effectiveness and risks. Negotiations over the pricing and terms of a parametric risk pool would make divergent judgments explicit and quantitative. Reduced-rate insurance would provide a way for states that favour implementation to demonstrate their confidence in solar geoengineering by underwriting risk transfer and ensuring compensation without the need for attribution. This would offer a powerful incentive for states opposing implementation to moderate their opposition.

Key policy insights

• States favouring deployment of solar geoengineering will need to address other states’ objections—unilateralism is implausible in practice

• This might be partially achieved using parametric climate risk insurance based on objective indicators

• A sovereign risk pool offering reduced-rate parametric insurance underwritten by states backing deployment could facilitate cooperation on solar geoengineering deployment

• States favouring deployment would demonstrate their confidence in solar geoengineering by supporting the risk pool

• Opposing states would be insured against solar geoengineering risks and proposing states would be incentivized to guard against overconfidence

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