Impact of royalties from forest resources on community development in Boki Local Government in Cross River State,Nigeria     

Titus E. Amalu  Anim O. Ajake  Patrick O. Obi 《GeoJournal》2016,81(3):475-487

The purpose of the study was to examine the extent to which royalties generated from forest resources contributed to community development in Boki Local Government area of Cross River State, Nigeria. The study used questionnaire survey of house-hold heads and Interview with focus groups to obtain data for this study. A total of 224 household heads representing 20 % of the available house-hold heads in the area was used for the study. The data collected were presented using tables and charts while an inferential statistics (Pearson’s Product Moment correlation) was employed to test the hypothesis of the study. The result of the analysis revealed that there exist a positive correlation coefficient of 0.911 which indicates a strong and positive relationship between royalties collected from forest resources and the number of developmental projects in the study area. Based on the findings of this study, it was recommended that more efforts be directed towards the monitoring and regulation of forest resource exploration activities in the area to ensure that royalties collected are directed towards the establishment of more developmental projects in the area so as to impact more positively on the living standard of the people.  相似文献   

Searching for Added Value in Simulating Climate Extremes with a High-Resolution Regional Climate Model over Western Canada     

Charles L. Curry  Bárbara Tencer  Kirien Whan  Andrew J. Weaver  Michel Giguère  Edward Wiebe 《大气与海洋》2016,54(4):364-384

We evaluate the capacity of a regional climate model to represent observed extreme temperature and precipitation events and also examine the impact of increased resolution, in an effort to identify added value in this respect. Two climate simulations of western Canada (WCan) were conducted with the Canadian Regional Climate Model (version 4) at 15 (CRCM15) and 45?km (CRCM45) horizontal resolution driven at the lateral boundaries by data from the European Centre for Medium-range Weather Forecasts (ECMWF) 40-year Reanalysis (ERA-40) for the period 1973–1995. The simulations were evaluated using the spline-interpolated dataset ANUSPLIN, a daily observational gridded surface temperature and precipitation product with a nominal resolution of approximately 10?km. We examine a range of climate extremes, comprising the 10th and 90th percentiles of daily maximum (TX) and minimum (TN) temperatures, the 90th percentile of daily precipitation (PR90), and the 27 core Climate Daily Extremes (CLIMDEX) indices.

Both simulations exhibit cold biases compared with observations over WCan, with the bias exacerbated at higher resolution, suggesting little added value for temperature overall. There are instances, however, of regional improvement in the spatial pattern of temperature extremes at the higher resolution of CRCM15 (e.g., the CLIMDEX index for the annual number of days when TX?>?25°C). The high-resolution simulations also reveal similarly localized features in precipitation (e.g., rain shadows) that are not resolved at the 45?km resolution. With regard to precipitation extremes, although both simulations generally display wet biases, CRCM15 features a reduced bias in PR90 in all seasons except winter. This improvement occurs despite the fact that spatial and interannual variability of PR90 in CRCM15 is significantly overestimated relative to both CRCM45 and ANUSPLIN. We posit that these characteristics are the result of demonstrable differences between corresponding topographical datasets used in the gridded observations and CRCM, the resulting errors propagated to physical variables tied to elevation and the beneficial effect of subsequent spatial averaging. Because topographical input is often discordant between simulations and gridded observations, it is argued that a limited form of spatial averaging may contribute added value beyond that which has already been noted in previous studies with respect to small-scale climate variability.  相似文献   

Climate adaptation at what scale? Multi-level governance,resilience, and coproduction in Saint Louis,Senegal     

Trond Vedeld  Adrien Coly  Ndèye Marème Ndour  Siri Hellevik 《Natural Hazards》2016,82(2):173-199

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Using radon-222 to study coastal groundwater/surface-water interaction in the Crau coastal aquifer (southeastern France)     

Adriano Mayer  Bach Thao Nguyen  Olivier Banton 《Hydrogeology Journal》2016,24(7):1775-1789

Radon has been used to determine groundwater velocity and groundwater discharge into wetlands at the southern downstream boundary of the Crau aquifer, southeastern France. This aquifer constitutes an important high-quality freshwater resource exploited for agriculture, industry and human consumption. An increase in salinity occurs close to the sea, highlighting the need to investigate the water balance and groundwater behavior. Darcy velocity was estimated using radon activities in well waters according to the Hamada “single-well method” (involving comparison with radon in groundwater in the aquifer itself). Measurements done at three depths (7, 15 and 21 m) provided velocity ranging from a few mm/day to more than 20 cm/day, with highest velocities observed at the 15-m depth. Resulting hydraulic conductivities agree with the known geology. Waters showing high radon activity and high salinity were found near the presumed shoreline at 3,000 years BP, highlighting the presence of ancient saltwater. Radon activity has also been measured in canals, rivers and ponds, to trace groundwater discharges and evaluate water balance. A model of the radon spatial evolution explains the observed radon activities. Groundwater discharge to surface water is low in pond waters (4 % of total inputs) but significant in canals (55 l/m²/day).  相似文献   

Identification of hydrochemical facies in the Roswell Artesian Basin,New Mexico (USA), using graphical and statistical methods     

Brent D. Newman  Kay C. Havenor  Patrick Longmire 《Hydrogeology Journal》2016,24(4):819-839

Analysis of groundwater chemistry can yield important insights about subsurface conditions, and provide an alternative and complementary method for characterizing basin hydrogeology, especially in areas where hydraulic data are limited. More specifically, hydrochemical facies have been used for decades to help understand basin flow and transport, and a set of facies were developed for the Roswell Artesian Basin (RAB) in a semi-arid part of New Mexico, USA. The RAB is an important agricultural water source, and is an excellent example of a rechargeable artesian system. However, substantial uncertainties about the RAB hydrogeology and groundwater chemistry exist. The RAB was a great opportunity to explore hydrochemcial facies definition. A set of facies, derived from fingerprint diagrams (graphical approach), existed as a basis for testing and for comparison to principal components, factor analysis, and cluster analyses (statistical approaches). Geochemical data from over 300 RAB wells in the central basin were examined. The statistical testing of fingerprint-diagram-based facies was useful in terms of quantitatively evaluating differences between facies, and for understanding potential controls on basin groundwater chemistry. This study suggests the presence of three hydrochemical facies in the shallower part of the RAB (mostly unconfined conditions) and three in the deeper artesian system of the RAB. These facies reflect significant spatial differences in chemistry in the basin that are associated with specific stratigraphic intervals as well as structural features. Substantial chemical variability across faults and within fault blocks was also observed.  相似文献   

A semi-implicit method for incompressible three-phase flow in porous media     

Justin Dong  Béatrice Rivière 《Computational Geosciences》2016,20(6):1169-1184

In this paper, we present a semi-implicit method for the incompressible three-phase flow equations in two dimensions. In particular, a high-order discontinuous Galerkin spatial discretization is coupled with a backward Euler discretization in time. We consider a pressure-saturation formulation, decouple the pressure and saturation equations, and solve them sequentially while still keeping each equation implicit in its respective unknown. We present several numerical examples on both homogeneous and heterogeneous media, with varying permeability and porosity. Our results demonstrate the robustness of the scheme. In particular, no slope limiters are required and a relatively large time step may be taken.  相似文献   

The Relationship Between Shoreline Armoring and Adjacent Submerged Aquatic Vegetation in Chesapeake Bay and Nearby Atlantic Coastal Bays     

Christopher J. Patrick  Donald E. Weller  Micah Ryder 《Estuaries and Coasts》2016,39(1):158-170

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Structural and Functional Composition of Benthic Nematode Assemblages During a Natural Recovery Process of <Emphasis Type="Italic">Zostera noltii</Emphasis> Seagrass Beds     

Patrick Materatski  Anna-Maria Vafeiadou  Tom Moens  Helena Adão 《Estuaries and Coasts》2016,39(5):1478-1490

In 2008, the stable seagrass beds of the Mira estuary (SW Portugal) disappeared completely; however, during 2009, they have begun to present early symptoms of natural recovery, characterised by a strongly heterogeneous distribution. This study was designed to investigate the spatial and temporal variability patterns of species composition, densities and trophic composition of the benthic nematode assemblages in this early recovery process, at two sampling sites with three stations each and at five sampling occasions. Because of the erratic and highly patchy seagrass recovery and the high environmental similarity of the two sampling sites, we expected within-site variability in nematode assemblages to exceed between-site variability. However, contrary to that expectation, whilst nematode genus composition was broadly similar between sites, nematode densities differed significantly between sites, and this between-site variability exceeded within-site variability. This may be linked to differences in the Zostera recovery patterns between both sites. In addition, no clear temporal patterns of nematode density, trophic composition and diversity were evident. Nematode assemblages generally resembled those of other estuarine muddy intertidal areas, which have a high tolerance of stress conditions.  相似文献   

Feedstocks study on CO<Subscript>2</Subscript> mineralization technology     

Heping Xie  Liang Tang  Yufei Wang  Tao Liu  Zhengmeng Hou  Jinlong Wang  Tao Wang  Wen Jiang  Patrick Were 《Environmental Earth Sciences》2016,75(7):615

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Tidal Marsh Restoration Design Affects Feedbacks Between Inundation and Elevation Change     

Lotte Oosterlee  Tom J. S. Cox  Wouter Vandenbruwaene  Tom Maris  Stijn Temmerman  Patrick Meire 《Estuaries and Coasts》2018,41(3):613-625

Tidal marsh (re)creation on formerly embanked land is increasingly executed along estuaries and coasts in Europe and the USA, either by restoring complete or by reduced tidal exchange. Ecosystem functioning and services are largely affected by the hydro-geomorphologic development of these areas. For natural marshes, the latter is known to be steered by feedbacks between tidal inundation and sediment accretion, allowing marshes to reach and maintain an equilibrium elevation relative to the mean sea level. However, for marsh restoration sites, these feedbacks may be disturbed depending on the restoration design. This was investigated by comparing the inundation-elevation change feedbacks in a natural versus restoration site with reduced tidal exchange in the Scheldt estuary (Belgium). This study analyzes long-term (9 years) datasets on elevation change and tidal inundation properties to disentangle the different mechanisms behind this elevation-inundation feedback. Moreover, subsequent changes in sediment properties that may affect this feedback were explored. In the restoration area with reduced tidal exchange, we found a different elevation-inundation feedback than on natural marshes, which is a positive feedback on initially high sites (i.e., sediment accretion leads to increasing inundation, hence causing accelerating sediment accretion rates) and a gradual silting up of the whole area. Furthermore, there is evidence for the presence of a relict consolidated sediment layer. Consequently, shallow subsidence is less likely to occur. Although short-term ecological development of the tidal marsh was not impeded, long-term habitat development may be affected by the differences in hydro-geomorphological interactions. An increase of inundation frequency on the initially high sites may cause inhibition of habitat succession or even reversed succession. Over time, the climax state of the restoration area may be different compared to natural marshes. Moreover, sediment-related ecosystem services, such as nutrient and carbon burial, may be positively influenced because of continuing sedimentation, although flood water storage potential will decrease with increasing elevation. Depending on the restoration goals, ecosystem trajectories and delivery of ecosystem services can be controlled by adaptive management of the tidal volume entering the restoration area.  相似文献