Temporal variations in the specific stream power and total energy expenditure of a monsoonal river: The Tapi River, India

In this study, an attempt has been made to evaluate the temporal variations in specific stream power and the total energy available for geomorphic work during the monsoon season for the Tapi River, in central India. Continuous daily discharge data (1978–1990), hydraulic geometry equations and the relationship between discharge and water surface slope were used to compute the daily specific stream power (ω) for the Savkheda gauging site in the lower Tapi Basin. The total amount of energy generated by all the monsoon flows was estimated by integrating the area under the ω-graph derived for the monsoon season.The analyses of the 13-year daily discharge data reveal that the average and maximum ω values range from 4–20 W m^{− 2}, and 22–964 W m^{− 2} respectively. Specific stream power duration curve derived for the site shows that for 25% of the time the power per unit area is > 10 W m^{− 2}. Furthermore, unit stream power was found to be above the Williams' [Williams, G.P., 1983. Paleohydrological methods and some examples from Swedish fluvial environments. I. Cobble and boulder deposits. Geografiska Annaler 65A, 227–243.] threshold of pebble-movement (1.5 W m^{− 2}), cobble-movement (16 W m^{− 2}) and boulder-movement (90 W m^{− 2}) for 71%, 15% and 2% of the time, respectively. Computations further indicate that the total amount of energy generated by the flows during the monsoon season is in the range of 37 MJ (deficit monsoon years) to 256 MJ (excess monsoon and/or flood years). Large floods have one-third share in the total monsoon energy expenditure. In the absence of appropriate data on the yearwise geomorphic effects, the geomorphic work was evaluated in terms of the total suspended sediment load transported. The total monsoon sediment load is strongly related to the total monsoon energy. The results of the study indicate that the average flow competence and capacity are remarkably higher during wetter monsoon seasons and flood years than during the shorter and drier monsoon seasons.The present analyses demonstrate that the flows are geomorphically effective for a greater part of the monsoon season, except during the deficient monsoon years, and there is little doubt that large-magnitude floods are effective agents of geomorphic change in monsoonal rivers.     

复杂表、浅层地震地质条件激发效果的探讨

在复杂表、浅层地震地质条件区采用常规成孔方式比较困难、成本过高,为改善其激发、接收条件,提高复杂区地震勘探应用效果,选定典型目标区域,结合地震施工因素,对普通炸药（高爆速药柱）、聚能震源弹、地震枪、可控震源四种激发源作了对比试验,同时对检波器的组合接收也进行了试验。从试验资料分析,应优先使用可控震源车进行激发,对可控震源车无法施工的地段（如山坡地带等）采用炸药震源激发,且同等条件下,优先考虑聚能震源弹。     

生态地球化学调查在草莓种植区环境评价中的应用

生态地球化学调查是一项正在兴起的学科,目前主要在环境、农业、土地资源评价等领域中得到应用.本文就地球化学调查在特色农产品种植区环境和种植适宜性评价方面的应用做了初步探讨,对安徽省某草莓种植区的土壤环境质量、土壤条件、种植适宜性进行了评价和种植区规划.     

地质科研与勘查一体化的实践与思考

文章从地质科技管理视角,论述了我院提出地质科研与勘查一体化的理念与含义,阐明了地质科研与勘查一体化的作用与成效,简要介绍了我院与地质科研与勘查一体化找矿相关的几个典型实例,并对我院地质科研与勘查一体化改革实践进行了初步总结。地质科研与勘查一体化不仅解决了行业地质科研的生存和发展问题,而且在当前找矿难度日益增大的背景下,将成为提升地质找矿能力的重要有效途径,具有十分广阔的发展前景。     

福山凹陷白莲流二段储层分类方法

福山凹陷白莲地区流二段砂岩储层具有埋藏深、砾石发育、孔隙结构复杂等特点,测井难以准确评价该区储层的有效性。针对这一问题,首先通过分析岩心实验资料,明确了影响该地区储层孔隙结构的主要因素为骨架颗粒接触性质,即喉道性质;其次在此研究基础上,开展了基于压汞实验数据表征储层有效性方法研究,根据反映岩石孔喉的参数（最大半径、平均半径、中值半径、分选系数）和岩石孔隙度构建了表征储层渗流和储集流体能力的综合性指数,并结合试油资料建立了该地区储层分类标准;最后利用回归分析的方法刻度常规测井数据,实现了利用常规测井数据进行储层有效性的评价,并应用在实际生产中,测井解释符合率由原来的72%提高到80%。     

Evaluating crude oil chemical dispersion efficacy in a flow-through wave tank under regular non-breaking wave and breaking wave conditions

Testing dispersant effectiveness under conditions similar to that of the open environment is required for improvements in operational procedures and the formulation of regulatory guidelines. To this end, a novel wave tank facility was fabricated to study the dispersion of crude oil under regular non-breaking and irregular breaking wave conditions. This wave tank facility was designed for operation in a flow-through mode to simulate both wave- and current-driven hydrodynamic conditions. We report here an evaluation of the effectiveness of chemical dispersants (Corexit^® EC9500A and SPC 1000^™) on two crude oils (Medium South American [MESA] and Alaska North Slope [ANS]) under two different wave conditions (regular non-breaking and plunging breaking waves) in this wave tank. The dispersant effectiveness was assessed by measuring the water column oil concentration and dispersed oil droplet size distribution. In the absence of dispersants, nearly 8-19% of the test crude oils were dispersed and diluted under regular wave and breaking wave conditions. In the presence of dispersants, about 21-36% of the crude oils were dispersed and diluted under regular waves, and 42-62% under breaking waves. Consistently, physical dispersion under regular waves produced large oil droplets (volumetric mean diameter or VMD ? 300 μm), whereas chemical dispersion under breaking waves created small droplets (VMD ? 50 μm). The data can provide useful information for developing better operational guidelines for dispersant use and improved predictive models on dispersant effectiveness in the field.     

Parentage determination of black sea bream(Acanthopagrus schlegelii) for stock enhancement:effectiveness and loss of genetic variation

The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of black sea bream stock enhancement.In order to detect the contribution of released individuals in Zhujiang River Estuary(ZRE) and Daya Bay(DB),six microsatellite markers were used to identify the hatchery-released individuals.In addition,this pedigree of hatchery populations(broodfish and hatchery-released offspring) was traced to detect the number of effective parents(N_e),the inbreeding coefficient and the decrease of genetic variability in the reproduction.The pedigree reconstruction showed that at least 69(out of 93) broodfish had offspring.The estimated N_e was 54.8,consequently the inbreeding coefficient was 0.91%.The genetic diversity of hatchery-released offspring was lower than that in that of broodfish(heterozygosity alleles,0.727-0.774),some alleles(number of alleles,61-69) and genetic variance were lost during reproduction.It was observed that wild samples had higher levels of genetic diversity compared with hatchery populations as well as recaptured samples in releasing area.A total of 128 hatchery-released black sea bream were identified among 487 recaptured samples in ZRE,while a total of 15 samples were identified among 96 samples in DB.In summary,there was a high survival of released fish.Nevertheless,the results provided evidence to consider a loss of genetic variation in hatcheryreleased stock and a negative genetic effect of the stock enhancement.     

华东地区地震条带预报效能评估

对华东地区1970年以来的地震条带进行了预报效能评估。 结果表明: M_L≥3.0地震条带的报准率为0.33, 虚报率为0.67, 漏报率为0.71, R值为0.20; M_L≥3.5地震条带的报准率为0.40, 虚报率为0.60, 漏报率为0.81, R值为0.12; M_L≥4.0地震条带的报准率为0.71, 虚报率为0.29, 漏报率为0.76, R值为0.18; 各震级档条带的R值等于或高于具有97.5%置信水平的R₀值, 具有一定的预报能力。 主震一般发生在条带结束后1年时间内, 多数发生在条带内部和边缘, 条带以北东向或北北东向居多; 对于条带的平均持续时间, 震级下限越大的条带平均持续时间越长; 多数条带分布在江苏及附近海域和赣北及邻区。     

Post-fire soil erosion mitigation at the scale of swales using forest logging residues at a reduced application rate

Mulching with forest residues has proved to be highly effective in reducing post-fire soil losses at the plot scale. However, its effectiveness has not been quantified at the application rates that are typically used in operational post-fire land management (2–3 Mg ha^-1 using straw), as well as at scales larger than 100 m². The present study compared post-fire erosion rates for six convergent hillslopes or swales of 500 to 800 m², three of which were left untreated while the other three were mulched immediately after the fire with shredded eucalypt bark at a rate of 2.4 Mg ha^-1. Erosion rates were monitored at irregular intervals during the first three post-fire years, whilst ground cover was assessed yearly. Selected topsoil properties (0–2 cm) such as organic matter content and aggregate stability were determined at a single occasion – two years after the wildfire, for three micro-environments separately: bare soil, and under mulch/litter and vegetation. Soil losses on the untreated swales decreased with post-fire year from 2.2 to 0.4 and 0.11 Mg ha^-1 yr^-1 (respectively for the first, second and third post-fire years), while the mulched swales produced 84%, 77% and 38% less soil losses than the untreated swales. Soil losses also depended on slope aspect, with the north-facing swales producing less erosion than the west-facing ones. This could be linked to their significant differences in bare soil, vegetation and stone cover, or a combination thereof. The type of micro-environment also played a significant role in topsoil properties (stone content, bulk density, resistance to penetration/shear stress, porosity and organic matter content). The present results add to the increasing evidence that forest residues should be duly considered for operational post-fire land management. Forest residues were highly effective in reducing erosion from swales at application rates as low as the typical 2 Mg ha^-1 of post-fire straw mulch. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.     

华东地区地震空区预报效能评估

对华东地区1970年以来的地震空区进行了预报效能评估。 结果表明: M_L≥3.0地震空区的报准率为0.45, 虚报率为0.55, 漏报率为0.57, R值为0.26; M_L≥3.5地震空区的报准率为0.31, 虚报率为0.69, 漏报率为0.75, R值为0.08; M_L≥4.0地震空区无对应的M_S5.5以上地震。 M_L≥3.0地震空区的R值高于具有97.5%置信水平的R₀值, 具有一定的预报能力, M_L≥3.5和M_L≥4.0地震空区不具有预报能力。 主震一般发生在空区内部边缘, 震前空区一般不会被打破; 空区的持续时间、 空区尺度、 震级下限与主震震级无明显线性关系; 空区主要分布在江苏、 山东及附近海域。