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11.
Lauren M. Candlish Richard L. Raddatz Geoffrey G. Gunn Matthew G. Asplin David G. Barber 《大气与海洋》2013,51(3):249-264
Abstract This study presents a semi‐analytic non‐iterative solution for the Monin‐Obukhov similarity equations under unstable surface conditions. The solution is represented in terms of the non‐dimensional Monin‐Obukhov stability parameter z/L. This parameter is given as a function of the bulk Richardson number and other surface parameters including the heat and momentum roughness lengths which are generally assumed to be different in this formulation. The proposed formulations give results that are both quantitatively and qualitatively consistent with the fully iterated numerical solution for a wide range of surface parameters. 相似文献
12.
N. Brice Orange Hakeem M. Oluseyi David L. Chesny Maulik Patel Katie Hesterly Lauren Preuss Chantale Neira Niescja E. Turner 《Solar physics》2014,289(5):1557-1584
Since their discovery 20 year ago, transition region bright points have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a transition region bright point (TR BP), a coronal bright point (CBP) and a blinker. We use time-series observations of the extreme-ultraviolet emission lines of a wide range of temperature T (logT=5.3?–?6.4) from the EUV Imaging Spectrometer (EIS) onboard the Hinode satellite. We present the EIS temperature maps and Doppler maps, which are compared with magnetograms from the Michelson Doppler Imager (MDI) onboard the SOHO satellite. Doppler velocities of the TR BP and blinker are ≤?25 km?s?1, which is typical of transient TR phenomena. The Doppler velocities of the CBP were found to be ≤?20 km?s?1 with exception of those measured at logT=6.2 where a distinct bi-directional jet is observed. From an EM loci analysis we find evidence of single and double isothermal components in the TR BP and CBP, respectively. TR BP and CBP loci curves are characterized by broad distributions suggesting the existence of unresolved structure. By comparing and contrasting the physical characteristics of the events we find that the BP phenomena are an indication of multi-scaled self-similarity, given the similarities in both their underlying magnetic field configuration and evolution in relation to EUV flux changes. In contrast, the blinker phenomena and the TR BP are sufficiently dissimilar in their observed properties as to constitute different event classes. Our work is an indication that the measurement of similar characteristics across multiple event types holds class-predictive power, and is a significant step towards automated solar atmospheric multi-class classification of unresolved transient EUV sources. Finally, the analysis performed here establishes a connection between solar quiet region CBPs and jets. 相似文献
13.
Lauren E. Watt Phil A. Bland Dave J. Prior Sara S. Russell 《Meteoritics & planetary science》2006,41(7):989-1001
Abstract— Fabric analysis of the interstitial matrix material in primitive meteorites offers a novel window on asteroid formation and evolution. Electron backscatter diffraction (EBSD) has allowed fabrics in these fine‐grained materials to be visualized in detail for the first time. Our data reveal that Allende, a CV3 chondrite, possesses a uniform, planar, short‐axis alignment fabric that is pervasive on a broad scale and is probably the result of deformational shortening related to impact or gravitational compaction. Interference between this matrix fabric and the larger, more rigid components, such as dark inclusions (DIs) and calcium‐aluminium‐rich inclusions (CAIs), has lead to the development of locally oriented and intensified matrix fabrics. In addition, DIs possess fabrics that are conformable with the broader matrix fabric. These results suggest that DIs were in situ prior to the deformational shortening event responsible for these fabrics, thus providing an argument against dark inclusions being fragments from another lithified part of the asteroid (Kojima and Tomeoka 1996; Fruland et al. 1978). Moreover, both DIs and Allende matrix are highly porous (?25%) (Corrigan et al. 1997). Mobilizing a highly porous DI during impact‐induced brecciation without imposing a fabric and incorporating it into a highly porous matrix without significantly compacting these materials is improbable. We favor a model that involves Allende DIs, CAIs, and matrix accreting together and experiencing the same deformation events. 相似文献
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The “White male effect” has been presented in past literature as a way to explain the tendency for White males to have lower environmental concern and risk perceptions than female and non-White individuals. Recently, research has proposed the “White male effect” may be a “conservative White male effect,” due to findings that political ideology impacts environmental concern. This study used a sample of young college-educated adults from Generation Z to test whether the conservative White male effect is present for environmental concern and ambivalence toward a proenvironmental worldview in this younger generation. Online surveys were distributed to undergraduate students at a large northeastern university in spring of 2016. A total of 1,940 surveys were returned. Results showed a lack of a unique White male, or conservative White male, effect above and beyond differences explained by gender, Whiteness, and political affiliation. The implications of this effect’s absence are discussed. 相似文献
16.
North American forests provide multiple ecosystem services, such as carbon storage, biodiversity, and recreation. These services are often coordinated through multifunctional management, whereby various users and owners contribute to collective agendas. Forests in exurban “transition” zones are crucial components in the sustainability of broader metropolitan landscapes, but represent a particularly understudied confluence of ecosystem services and multifunctional management. In this paper, we develop a place-based approach to assess ecosystem services in transitional forests (those between rural and urban). We demonstrate how trajectories of forest composition are linked with shifting ecosystem services that both shape and are shaped by management activities. Sited in Stinchfield Woods, a forest in southeast Michigan, this study draws on a household survey, interviews, ecological data, and archival information. Given variations in priorities over time and among different users, we suggest that coordinated, adaptive management may improve provisioning of ecosystem services in ways that benefit multiple users. 相似文献
17.
Social scientists and science communicators are concerned about the apparent discrepancy between the scientific consensus on climate change (Anderegg et al. Proc Natl Acad Sci 107:12107–12109, 2010; Doran and Zimmerman EOS Trans Am Geophys Union 90:22–3, 2009) and the general public’s views (Knight Environ Sociol 2:101–113, 2016; Lee et al. Nat Clim Chang 5:1014–1020, 2015). It is reasoned that increased public awareness and perceived threat of climate change may pressure governments to enact policy to counteract climate change (e.g. setting stringent carbon emissions targets). Despite a logical link between public awareness and government-set emissions targets, this relationship remains untested. We examined the relationship between public awareness about and perceived threat of climate change and governmental emissions targets across 71 countries and 1 region. We found a positive association between the proportions of a country’s population that are aware of climate change and the unconditional emissions reduction targets set by that country in the Paris Agreement (Rogelj et al. Nature 534:631–639, 2016). However, the proportion of people in a country who perceive climate change as a personal threat was not associated with higher emissions reduction targets. Our results suggest that public awareness may be an important part of garnering the public support required for policies designed to mitigate climate change to succeed. 相似文献
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Jordan A. Rosencranz Lauren N. Brown James R. Holmquist Yareli Sanchez Glen M. MacDonald Richard F. Ambrose 《Estuaries and Coasts》2017,40(5):1371-1384
Salt marsh resilience to sea-level rise depends on marsh plain elevation, tidal range, subsurface processes, as well as surface accretion, of which suspended-sediment concentration (SSC) is a critical component. However, spatial and temporal patterns of inorganic sedimentation are poorly quantified within and across Salicornia pacifica (pickleweed)-dominated marshes. We compared vertical accretion rates and re-examined previously published suspended-sediment patterns during dry-weather periods at Seal Beach Wetlands, which is characterized by a mix of Spartina foliosa (cordgrass) and pickleweed, and for Mugu Lagoon, where cordgrass is rare. Mugu Lagoon occurs higher in the tidal frame and receives terrigenous sediment from an adjacent creek. Feldspar marker horizons were established in winter 2013–2014 to measure accretion. Accretion rates at Seal Beach Wetlands and Mugu Lagoon were 6 ± 0.5 mm/year (mean ± SE) and 2 ± 0.3 mm/year. Also, the estimated sediment flux (g/year) across the random feldspar plots was 3.5 times higher at Seal Beach Wetlands. At Mugu Lagoon, accretion was higher near creeks, although not statistically significant. Dry-weather SSC showed similar concentrations at transect locations across sites. During wet weather, however, SSC at Mugu Lagoon increased at all locations, with concentrations decaying farther than 8 m from tidal creek edge. Based on these results from Mugu Lagoon, we conclude accretion patterns are set by infrequent large flooding events in systems where there is a watershed sediment source. Higher accretion rates at Seal Beach Wetlands may be linked to lower-marsh elevations, and thus more frequent inundation, compared with Mugu Lagoon. 相似文献
20.
Lauren Norman T. Max Friesen 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):261-278
Geografisk Tidsskrift—Danish Journal of Geography 110(2):261–278, 2010 In a comprehensive overview of evidence for fishing in the Thule period of the eastern North American Arctic, Whitridge (2001) noted that fish bones are either extremely rare or absent in archaeofaunal samples, despite the fact that artifact assemblages typically contain a variety of fishing implements. In this paper, we present new faunal data from two sites on southeastern Victoria Island, Nunavut, which offer a marked contrast to this pattern. The Pembroke site, located just north of Cambridge Bay, is a small Thule site probably occupied during an early migration into the region. The Bell site, located on the Ekalluk River, is a more substantial site, occupied for a much longer duration during the Thule period. These sites are located in areas devoid of many taxa preferred by Thule peoples, which led the sites' occupants to rely on caribou and fish for much of their winter subsistence. At the Bell site, storage of caribou and fish was critical for winter survival. However, the occupants of the Pembroke site appear to have been unable to acquire sufficient stores during the fall, and therefore relied on fishing through the ice during winter to supplement their inadequate stores. Although both sites indicate a more important economic role for fish than has been recorded on any other eastern Arctic Thule winter site, the use of fish at the two sites differs markedly, adding nuance to archaeologically known Thule subsistence patterns. 相似文献