Effects of land-cover and watershed protection futures on sustainable groundwater management in a heavily utilized aquifer in Hawai‘i (USA)     

Bremer  Leah L.  Elshall  Ahmed S.  Wada  Christopher A.  Brewington  Laura  Delevaux  Jade M.S.  El-Kadi  Aly I.  Voss  Clifford I.  Burnett  Kimberly M. 《Hydrogeology Journal》2021,29(5):1749-1765

Hydrogeology Journal - Groundwater sustainability initiatives, including sustainable yield and watershed policy protection policies, are growing globally in response to increasing demand for...  相似文献   

Farm-scale adaptation and vulnerability to environmental stresses: Insights from winegrowing in Northern California     

Kimberly A. Nicholas  William H. Durham 《Global Environmental Change》2012,22(2):483-494

The wine industry is increasingly recognized as especially vulnerable to climate change due to the climate sensitivity of both winegrape yields and quality, making it an important model system for the agricultural impacts of global changes. However, agricultural production is strongly influenced by the management decisions of growers, including their practices to modify the microclimate experienced by the growing crop; these adaptations have not been studied at the vineyard level, where managers on the ground are on the front lines of responding to global change.We conducted 20 in-depth interviews with winegrowers to examine farm-scale adaptive responses to environmental stresses, to understand the views and motivations of agricultural managers, and to explore adaptive capacity in practice. We found that growers tend to respond to stresses individually rather than collectively, except when facing severe, unfamiliar pests and diseases. Responses may be reactive or anticipatory; most anticipatory strategies have been short-term, in response to imminent threats. Growers tend to rely on their own experience to guide their management decisions, which may offer poor guidance under novel climate regimes. From using a Vulnerability Scoping Diagram, we find that changing exposure (vineyard location) and sensitivity (planting choices such as vine variety) have the biggest impact on reducing vulnerability, but that adaptations in growing or processing the crop in the vineyard and winery are easier to implement, much more commonly undertaken, and may also offer substantial adaptive capacity. Understanding the context of adaptations, as well as the decision-making processes motivating them, is important for understanding responses to global change.These findings highlight some innovations in adapting to global change, as well as some of the barriers, and point to the need for strategic investments to enhance agricultural resilience to climate change. In particular, strategies to enhance both effective and easy to implement farming adaptations, as well as broader-scale anticipatory, collective responses, could reduce vulnerability in the context of climate change.  相似文献   

The Homo habitat niche: using the avian fossil record to depict ecological characteristics of Palaeolithic Eurasian hominins     

Clive Finlayson  José Carrión  Kimberly Brown  Geraldine Finlayson  Antonio Sánchez-Marco  Darren Fa  Joaquín Rodríguez-Vidal  Santiago Fernández  Elena Fierro  Marco Bernal-Gómez  Francisco Giles-Pacheco 《Quaternary Science Reviews》2011,30(11-12):1525-1532

Although hardly applied to human palaeoecology, bird fossils offer a unique opportunity for quantitative studies of the hominin habitat. Here we reconstruct the Homo habitat niche across a large area of the Palaearctic, based on a database of avian fauna for Pleistocene sites. Our results reveal a striking association between Homo and habitat mosaics. A mix of open savannah-type woodland, wetlands and rocky habitats emerges as the predominant combination occupied by Homo across a wide geographical area, from the earliest populations of the Lower Palaeolithic to the latest hunter-gatherer communities of the Upper Palaeolithic. This observation is in keeping with the view that such landscapes have had long standing selective value for hominins.  相似文献   

Place,culture, and peace; treaty cities and national culture in mediating contemporary international disputes     

Stanley D. Brunn  Vaseema Nooruddin  Kimberly Sims 《GeoJournal》1996,39(4):331-343

Many changes in the political map are the result of negotiation between disputing states. Those discussions are held in states acceptable to the parties themselves and in sites selected by the host. Two significant cultural and political features of those discussions are the selection of the treaty site and the negotioting styles of the disputing parties and negotiator. We examine these themes with examples and suggest their importance in regional and global peace processes.  相似文献   

雪地上的森林冠层混合反照率模型   总被引：2，自引：0，他引：2  

蒋玲梅  杨华  王锦地  李小文  Kimberly J. Schaudt 《遥感学报》2003,7(6):433-439

反照率通常定义为出射与入射的能量之比，是地表能量平衡中的关键因子。气候变化对反照率也很敏感。典型的气候变化预测是通过GCM与地表模型的结合进行的。目前在地表模型(如BATS模型)中，是通过空气动力学粗糙度Z0与降雪深度d两个参数来估计雪地上树冠的反照率的。在他们的工作基础上，重点考虑对于不同的太阳天顶角，直入一扇出反照率的方向性及其与叶面积指数(LAI)的关系。同时，为了保持BATS模型所需反照率模型的基本特征，主要在几何光学-辐射传输混合模型(GORT)的基础上做了一些近似来达到此目的。最后，以针叶林为例，用MODIS的反照率数据和BOREAS地面观测数据做了初步的模型验证。结果显示模型较符合实际情况。  相似文献   

THE IMPACT OF METAL AND ORGANIC CONTAMINANTS ON THE STRUCTURE OF PERIPHYTON IN LOTIC SEDIMENTS: OBSERVATIONS AT VARIOUS SCALES     

Jill A. KOSTEL  Kimberly A. GRAY  Ann L. St. AMAND 《国际泥沙研究》2003,(2)

1 INTRODUCTION While wastewater discharge regulations have significantly reduced water column pollution, historical and accidental releases of organic pollutants and heavy metals continue to pose an ecological threat as these contaminants have become 搃n-place?sediment pollutants. It had been previously assumed that natural attenuation processes, such as burial or biodegradation, would decrease the contamination levels in surface sediments and, thus, diminish the environmental impact of t…  相似文献   

Forest-Landscape Structure along an Urban-To-Rural Gradient*     

Kimberly E. Medley  Mark J. McDonnell  Steward T. A. Pickett 《The Professional geographer》1995,47(2):159-168

Human activities and forest-landscape structure are examined along a belt transect that extends 140 km from New York City to northwestern Connecticut. The study quantifies urban structures (population density, land use. transportation) and processes (population growth, urban land development) in the transect, and tests for relationships with the distribution, sizes, and shapes of forests. Our results identify distinct characteristics of urban and suburban environments based on the landscape structure of native forest vegetation. These findings are applicable to the management of natural areas along a gradient of urbanization.  相似文献   

Sources and transformations of organic matter in surface soils and sediments from a tidal estuary (North Inlet, South Carolina, USA)   总被引：5，自引：0，他引：5  

Miguel A. Goñi  Kimberly A. Thomas 《Estuaries and Coasts》2000,23(4):548-564

Surface soil and sediment samples collected along a forest-brackish marsh-salt marsh transect in a southeastern U.S. estuary were separated into three different fractions (sand, macro-organic matter, and humus) based on size and density. Elemental, stable carbon isotope, and lignin analyses of these samples reveal important contrasts in the quantity, composition, and sources of organic matter, between forest and marsh sites. Elevated nitrogen contents in humus samples suggest nitrogen incorporation during humification is most extensive in forest soils relative to the marsh sites. The lignin compositions of the macro-organic and humus samples reflect the predominant type of vegetation at each site. Lignin phenol ratios indicate that woody and nonwoody litter from, gymnosperm and angiosperms trees (pines and oaks) is the major source of vascular plant-derived organic matter in the forest site and that angiosperm, grasses (Juncus andSpartina) are the major sources of lignin at the marsh sites. The phenol distributions also reveal that oxidative degradation of lignin is most extensive in the forest and brackish marsh zones whereas little lignin decay occurs in the salt marsh samples. In forest soils, most organic matter originates from highly altered forest vegetation while at the brackish marsh site organic matter is a mixture of degradedJuncus materials and microbial/algal remains. Organic matter in the salt marsh appears to be composed of a more complex mixture of sources, including degradedSpartina detritus as well as algal and microbial inputs. Microbial methane oxidation appears to be an important process and a source of¹³C depleted organic carbon in subsurface sediments at this site.  相似文献   

Probabilistic demand and fragility assessment of welded column splices in steel moment frames          下载免费PDF全文

Carmine Galasso  Kimberly Stillmaker  Christian Eltit  Amit Kanvinde 《地震工程与结构动力学》2015,44(11):1823-1840

An assessment of seismic demands and capacities of welded column splice (WCS) connections in steel moment frames is presented. For demand assessment, nonlinear dynamic analyses are conducted for two case‐study buildings, that is, a 4‐story and a 20‐story moment frame. Results from the nonlinear dynamic analyses are assessed through a probabilistic seismic demand analysis (PSDA) framework to characterize recurrence rates of longitudinal flange stress in these connections. The PSDA is applied in two contexts. First, in the context of WCS connections constructed prior to the M 6.7 1994 Northridge earthquake, the PSDA is combined with sophisticated finite element‐based fracture mechanics analysis to compute the mean annual frequencies of fracture in these connections. The pre‐Northridge WCS are especially critical because they feature partial joint penetration and brittle materials that compromise their resistance to fracture. The analysis indicates that the mean annual frequencies of fracture in these connections may be unacceptably high for both the 4‐story and the 20‐story frames. This warrants a serious and urgent consideration of retrofit strategies. These findings are attributed to the brittleness of the pre‐Northridge splices (as indicated by the fracture mechanics simulations), as well as the force‐controlled nature of these components, wherein low‐intensity ground motions contribute disproportionately to fracture risk, as evidenced by fracture risk disaggregation. Second, in the context of new construction, the PSDA provides meaningful stress magnitudes for design. Currently, WCS connections employ complete joint penetration welds with the intent to develop the smaller column flange in yielding. The PSDA conducted in this study suggests that this requirement may be too stringent because stress demands in the splices corresponding even to high return periods (e.g., 2475 years) are significantly lower (~40 ksi), as compared with the stress required to yield the column (~55 ksi). Limitations of the study are outlined. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Pristinity and petrogenesis of eucrites     

Jasmeet K. Dhaliwal  James M. D. Day  Kimberly T. Tait 《Meteoritics & planetary science》2023,58(2):275-295

New petrography, mineral chemistry, and whole rock major, minor, and trace element abundance data are reported for 29 dominantly unbrecciated basaltic (noncumulate) eucrites and one cumulate eucrite. Among unbrecciated samples, several exhibit shock darkening and impact melt veins, with incomplete preservation of primary textures. There is extensive thermal metamorphism of some eucrites, consistent with prior work. A “pristinity filter” of textural information, siderophile element abundances, and Ni/Co ratios of bulk rocks is used to address whether eucrite samples preserve endogenous refractory geochemical signatures of their asteroid parent body (i.e., Vesta), or could have experienced exogenous impact contamination. Based on these criteria, Cumulus Hills 04049, Elephant Moraine 90020, Grosvenor Range 95533, Pecora Escarpment 91245, and possibly Queen Alexander Range 97053 and Northwest Africa 1923 are pristine eucrites. Eucrite major element compositions and refractory incompatible trace element abundances are minimally affected by metamorphism or impact contamination. Eucrite petrogenesis examined through the lens of these elements is consistent with partial melting of a silicate mantle that experienced prior metal–silicate equilibrium, rather than as melts associated with cumulate diogenites. In the absence of the requirement of a large-scale magma ocean to explain eucrite petrogenesis, the interior structure of Vesta could be more heterogeneous than for larger planetary bodies.  相似文献