Reports from the Smithsonian’s Global Volcanism Network, December 2009     

Edward Venzke  Sally Kuhn Sennert  Richard Wunderman 《Bulletin of Volcanology》2010,72(5):639-640

Information included in this summary is based on more detailed reports published in the Bulletin of the Global Volcanism Network, vol. 34, no. 12, December 2009 (on the Internet at ). Edited by scientists at the Smithsonian, this bulletin includes reports provided by a worldwide network of correspondents. The reports contain the names and contact information for all sources. Please note that these reports are preliminary and subject to change as events are studied in more detail. The Global Volcanism Program welcomes further reports of current volcanism, seismic unrest, monitoring data, and field observations.  相似文献   

Reports from the Smithsonian’s Global Volcanism Network, April 2010     

Edward Venzke  Sally Kuhn Sennert  Richard Wunderman  Jen Fela  Jacquelyn Gluck 《Bulletin of Volcanology》2010,72(9):1137-1138

Information included in this summary is based on more detailed reports published in the Bulletin of the Global Volcanism Network, vol. 35, no. 4, April 2010 on the Internet at (). Edited by scientists at the Smithsonian, this bulletin includes reports provided by a worldwide network of correspondents. The reports contain the names and contact information for all sources. Please note that these reports are preliminary and subject to change as events are studied in more detail. The Global Volcanism Program welcomes further reports of current volcanism, seismic unrest, monitoring data, and field observations.  相似文献   

How much does dry‐season fog matter? Quantifying fog contributions to water balance in a coastal California watershed          下载免费PDF全文

Michaella Chung  Alexis Dufour  Rebecca Pluche  Sally Thompson 《水文研究》2017,31(22):3948-3961

The seasonally‐dry climate of Northern California imposes significant water stress on ecosystems and water resources during the dry summer months. Frequently during summer, the only water inputs occur as non‐rainfall water, in the form of fog and dew. However, due to spatially heterogeneous fog interaction within a watershed, estimating fog water fluxes to understand watershed‐scale hydrologic effects remains challenging. In this study, we characterized the role of coastal fog, a dominant feature of Northern Californian coastal ecosystems, in a San Francisco Peninsula watershed. To monitor fog occurrence, intensity, and spatial extent, we focused on the mechanisms through which fog can affect the water balance: throughfall following canopy interception of fog, soil moisture, streamflow, and meteorological variables. A stratified sampling design was used to capture the watershed's spatial heterogeneities in relation to fog events. We developed a novel spatial averaging scheme to upscale local observations of throughfall inputs and evapotranspiration suppression and make watershed‐scale estimates of fog water fluxes. Inputs from fog water throughfall (10–30 mm/year) and fog suppression of evapotranspiration (125 mm/year) reduced dry‐season water deficits by 25% at watershed scales. Evapotranspiration suppression was much more important for this reduction in water deficit than were direct inputs of fog water. The new upscaling scheme was analyzed to explore the sensitivity of its results to the methodology (data type and interpolation method) employed. This evaluation suggests that our combination of sensors and remote sensing allows an improved incorporation of spatially‐averaged fog fluxes into the water balance than traditional interpolation approaches.  相似文献   

Enabling adaptation? Lessons from the new ‘Green Revolution’ in Malawi and Kenya     

Sally Brooks 《Climatic change》2014,122(1-2):15-26

This article explores the extent to which efforts to improve productivity of smallholder agriculture through a new ‘Green Revolution’ in Sub Saharan Africa are likely to enhance the capacity of smallholder farmers to adapt to the impacts of climate change. Drawing on empirical material from Malawi and Kenya, the paper finds more conflicts than synergies between the pursuit of higher productivity through the promotion of hybrid maize adoption and crop diversification as a strategy for climate change adaptation. This is despite an oft-assumed causal link between escape from the ‘low maize productivity trap’ and progression towards crop diversification as an adaptive strategy. In both countries, a convergence of interests between governments, donors and seed companies, combined with a historical preference for, and dependence on maize as the primary staple, has led to a narrowing of options for smallholder farmers, undermining the development of adaptive capacities in the longer term. This dynamic is linked to the conflation of market-based variety of agricultural technologies, as viewed ‘from the top down’, with diversity-in-context, as represented by site-specific and locally derived and adapted technologies and institutions that can only be developed ‘from the bottom up’.  相似文献   

Impact of chemical and meteorological boundary and initial conditions on air quality modeling: WRF-Chem sensitivity evaluation for a European domain     

Mathias Ritter  Mathias D. Müller  Oriol Jorba  Eberhard Parlow  L.-J. Sally Liu 《Meteorology and Atmospheric Physics》2013,119(1-2):59-70

This study evaluates the impact of different chemical and meteorological boundary and initial conditions on the state-of-the-art Weather Research and Forecasting (WRF) model with its chemistry extension (WRF-Chem). The evaluation is done for July 2005 with 50 km horizontal resolution. The effect of monthly mean chemical boundary conditions derived from the chemical transport model LMDZ-INCA on WRF-Chem is evaluated against the effect of the preset idealized profiles. Likewise, the impact of different meteorological initial and boundary conditions (GFS and Reanalysis II) on the model is evaluated. Pearson correlation coefficient between these different runs range from 0.96 to 1.00. Exceptions exists for chemical boundary conditions on ozone and for meteorological boundary conditions on PM₁₀, where coefficients of 0.90 were obtained. Best results were achieved with boundary and initial conditions from LMDZ-INCA and GFS. Overall, the European simulations show encouraging results for observed air pollutant, with ozone being the most and PM₁₀ being the least satisfying.  相似文献   

Sedimentary stable carbon isotope evidence of late Quaternary vegetation and climate change in highland Costa Rica     

Chad S. Lane  Sally P. Horn  Claudia I. Mora  Kenneth H. Orvis  David B. Finkelstein 《Journal of Paleolimnology》2011,45(3):323-338

Continuous terrestrial records of paleoclimate and paleovegetation that extend to the late Pleistocene are rare for the circum-Caribbean uplands. In this study we analyzed the bulk and compound-specific carbon isotope composition of lake sediments spanning this period from Lago de las Morrenas 1 (LM1), a glacial lake in the highlands of southern Costa Rica, for evidence of climate and vegetation changes that may not have been apparent in previous analyses. The stable carbon isotope ratios of n-alkanes typically derived from terrestrial plants (δ¹³C_C27–C33) indicate an increased abundance of C₄ plant taxa during the late Pleistocene and earliest Holocene that may be related to decreased atmospheric carbon dioxide concentrations, increased aridity, or habitat availability. These n-alkane isotope ratios also provide evidence of more arid conditions during the early and late Holocene, and more mesic conditions during the middle Holocene, a pattern prevalent in other paleoclimate records from the region that is thought to be related to millennial-scale dynamics of the intertropical convergence zone (ITCZ). The sensitivity of the LM1 paleorecord to trade wind dynamics provides further support for the role of millennial-scale shifts in ITCZ dynamics in driving neotropical environmental change, and indicates that the effects of ITCZ migration were not limited to the lowlands.  相似文献   

Discussion of “tectonic activity in West Africa and the Gulf of Guinea since Jurassic times — An explanation based on membrane tectonics” by S.J. Freeth     

R.S. Thorpe  J.B. Wright 《Earth and Planetary Science Letters》1979,42(2):327-328

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LOS and ‘other minerals’     

Sally Meese 《Marine Policy》1983,7(2):123-124

Emphasis on mining of manganese nodules has led to a rules, regulations and procedures lacuna in the provisions for non-nodule minerals mining. Unless the regime governing the exploitation of‘other minerals’ is improved, the mining of polymetallic sulphides and other non-nodule minerals will be seriously affected.  相似文献   

The case for the defence     

Sally Meese 《Marine Policy》1983,7(1):56-57

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Calibrating pollen data in climatic terms: Improving the methods     

Sally Howe  Thompson Webb 《Quaternary Science Reviews》1983,2(1):17-51

When properly calibrated, Holocene pollen data provide an important source of quantitative information about Holocene climates. Multiple linear regression of modern climate and pollen data allows the development of statistical calibration functions that transform percentages of certain pollen types into quantitative estimates of climatic variables, and these functions, when applied to Holocene pollen data, yield estimates of climatic variables for past times. Confidence intervals for the climatic variables provide estimates of the statistical errors. These interval estimates are based upon the following statistical assumptions: (1) the regression model is appropriate; (2) the errors in measuring the climate variables are independent, normally distributed and have constant variance; and (3) no outliers are present. We outline the steps to be followed in calculating calibration functions, including (1) selecting the calibration region; (2) selecting a pollen sum; (3) analyzing scatter diagrams of a given climate variable against each pollen type; (4) deleting outliers and transforming pollen data; (5) performing the regression; and (6) testing the appropriateness of the statistical assumptions. We used available computer programs for most of this study. In addition, we developed new software to compute the Moran statistic to test for spatial autocorrelation among the regression residuals, using the dual of the Voronoi diagram to describe the spatial relationships among the sites. In order to illustrate the sequence of procedures, we used data from the lower peninsula of Michigan to develop a calibration function for July mean temperature and then used Holocene pollen data from central lower Michigan to estimate past temperatures.  相似文献