Differences in oxygen-18 content of throughfall and rainfall in hardwood and coniferous forests     

David R. Dewalle  Bryan R. Swistock 《水文研究》1994,8(1):75-82

The differences between δ¹⁸O in throughfall and open rainfall were studied for 16 selected spring and summer storms in deciduous, pine and spruce forests in central Pennsylvania, USA. Throughfall δ¹⁸O averaged 0.17, 0.32 and 0.24%_o greater than δ¹⁸O of open rainfall for all storms at the deciduous, pine and spruce sites, respectively. Throughfall ¹⁸O enrichment was greater in low intensity spring rainfall events than higher intensity growing season storms and greater in the coniferous stands than the deciduous hardwood stand. Maximum throughfall ¹⁸O enrichment of l.61%_o occurred in the spruce forest during one spring event. The differences between rainfall and throughfall ¹⁸O observed in this study for individual storm events may have important implications for isotope flow separation studies.  相似文献   

The Development And Application Of A Simple Methodology For Recording Rock Art Using Consumer-Grade Digital Cameras     

Jim H.  Chandler  Paul  Bryan  John G.  Fryer 《The Photogrammetric Record》2007,22(117):10-21

  相似文献   

Fractionation of pyroxene-phyric MORB at low pressure: An experimental study     

Grove  T. L.  Bryan  W. B. 《Contributions to Mineralogy and Petrology》1983,84(4):293-309

Contributions to Mineralogy and Petrology - One-atmosphere melting experiments are used to assess the role of clinopyroxene in producing the compositional variations observed in mid-ocean-ridge...  相似文献   

Dynamics of the down-going lithosphere     

Jack Oliver  Bryan Isacks  Muawia Barazangi  Walter Mitronovas 《Tectonophysics》1973,19(2):133-147

  相似文献   

Contrasted abyssal basalt liquidus trends: evidence for mantle major element heterogeneity     

W.B. Bryan  H.J.B. Dick 《Earth and Planetary Science Letters》1982,58(1):15-26

Natural submarine basalt glasses define liquidus trends which may be summarized as curvilinear regression lines in the normative plagioclase-pyroxene-olivine ternary. Individual basalt suites separated in time or space may differ in major element composition; these differences translate into systematic differences in normative plagioclase, leading to efficient discrimination of individual trends in this ternary. Comparison of two contrasted sets of trends to available experimental and petrographic data confirms the similarity of the natural basalt trends to those predicted by 1-atm experiments, in general agreement with earlier studies based on whole-rock data. These contasted liquidus trends are believed to reflect major element heterogeneity and varying degrees of melting of the mantle source. This major element heterogeneity is not simply correlated with heterogeneity in incompatible trace elements, and like incompatible trace element heterogeneity, there is growing evidence that it may vary abruptly in space and time. The existence of these compositionally contrasted basalt suites must be considered in petrogenetic modelling; specifically, they will introduce scatter in most generalized variation diagrams, and will increase the likelihood of “misfits” in fractionation calculations utilizing parent and residual compositions drawn from different suites.  相似文献   

Calibrating Environment Canada's MESH Modelling System over the Great Lakes Basin     

Amin Haghnegahdar  Bryan A. Tolson  Bruce Davison  Frank R. Seglenieks  Erika Klyszejko  Eric D. Soulis 《大气与海洋》2014,52(4):281-293

This paper reports on recent progress towards improved predictions of a land surface-hydrological modelling system, Modélisation Environmentale–Surface et Hydrologie (MESH), via its calibration over the Laurentian Great Lakes Basin. Accordingly, a “global” calibration strategy is utilized in which parameters for all land class types are calibrated simultaneously to a number of sub-basins and then validated in time and space. Model performance was evaluated based on four performance metrics, including the Nash-Sutcliffe (NS) coefficient and simulated compared with observed hydrographs. Results from two calibration approaches indicate that in the model validation mode, the global strategy generates better results than an alternative calibration strategy, referred to as the “individual” strategy, in which parameters are calibrated individually to a single sub-basin with a dominant land type and then validated in a different sub-basin with the same dominant land type. The global calibration strategy was relatively successful despite the large number of calibration parameters (51) and relatively small number of model evaluations (1000) used in the automatic calibration procedure. The NS values for spatial validation range from 0.10 to 0.72 with a median of 0.41 for the 15 sub-basins considered. Results also confirm that a careful model calibration and validation is needed before any application of the model.  相似文献   

ENSO modes of the equatorial Pacific Ocean in observations and CMIP5 models     

Bryan C. Weare 《Climate Dynamics》2014,43(5-6):1285-1301

El Niño/Southern Oscillation (ENSO) is the predominant interannual variability of the global climate system. How might ENSO change in a warmer world? The dominant two Combined Empirical Orthogonal Functions (CEOF) of the equatorial ocean temperature and zonal and vertical motion identify two modes that shown a transition in the eastern Pacific from a warming eastward/downward motion to a cooling westward/upward flow. These results also suggest consistent changes to the west and at depths down to 300 m. These dominate CEOFs provide a compact tool for assessing Coupled Model Intercomparison Project Phase 5 ocean model output for both the recent historical period and for the latter part of the twenty first century. Most of the analyzed models replicate well the spatial patterns of the dominant observational CEOF modes, but nearly always underestimate the magnitudes. Comparing model output for the twentieth and twenty first centuries there is very little change between the spatial patterns of the ENSO modes of the two periods. This lack of response to climate change is shown to be partly related to competing influences of climatic changes in the mean ocean circulation.  相似文献   

REDD+ projects and national-level Readiness processes: a case study from Kenya     

Florence Bernard  Peter A. Minang  Bryan Adkins  Jeremy T. Freund 《Climate Policy》2014,14(6):788-800

The Bali Action Plan and Cancun agreements on Reducing Emissions from Deforestation and forest Degradation, plus forest conservation, sustainable management of forests and enhancement of forest carbon stocks (REDD+) have encouraged demonstration activities as part of Readiness and a step towards national approaches. This has enabled important growth in pilot and demonstration projects. Yet an understanding about how these projects are connected and contribute to national-level technical, policy, and institutional preparedness (Readiness) for REDD+ is lacking. This article examines the linkages between national processes and the private-sector-driven Kasigau Corridor REDD+ project in Kenya. The study reveals interesting cross-scale interactions that have increased over time and have high potential for harnessing national-level processes through lessons from the project level. Key innovations from the Kasigau Corridor Project include the implementation of REDD+ in dry forests, operationalization of conservation easements in the context of REDD+, and demonstration of potential ways of obtaining upfront finance for REDD+. The study also provides a number of key recommendations for Kenya and REDD+ in general, including official endorsement of stand-alone REDD+ projects under national Readiness schemes and exploring jurisdictional and nested REDD+ approaches. Additionally, more accommodating national-level frameworks for attracting private-sector engagement and investments, and for integrating, scaling-out, or scaling-up lessons from such projects, would be needed to enhance national REDD+ Readiness.  相似文献   

Modeling land suitability/capability using fuzzy evaluation     

Fang Qiu  Bryan Chastain  Yuhong Zhou  Caiyun Zhang  Harini Sridharan 《GeoJournal》2014,79(2):167-182

Modeling the suitability of land to support specific land uses is an important and common GIS application. Three classic models, specifically pass/fail screening, graduated screening and weighted linear combination, are examined within a more general framework defined by fuzzy logic theory. The rationale underlying each model is explained using the concepts of fuzzy intersections, fuzzy unions and fuzzy averaging operations. These fuzzy implementations of the three classic models are then operationalized and used to analyze the distribution of kudzu in the conterminous United States. The fuzzy models achieve better predictive accuracies than their classic counterparts. By incorporating fuzzy suitability membership of environment factors in the modeling process, these fuzzy models also produce more informative fuzzy suitability maps. Through a defuzzification process, these fuzzy maps can be converted into conventional maps with clearly defined boundaries, suitable for use by individuals uncomfortable with fuzzy results.  相似文献