重庆“5.6”强风雹天气过程成因分析

利用常规观测、NCEP分析场及雷达、自动站等资料对重庆＂5.6＂强风雹天气的成因进行了分析,结果表明：冷锋和副热带高空急流在风雹发生地近乎重叠的配置结构促进了次级环流的形成并有利于上升运动的强烈发展;风暴天气发生前,下垫面强烈加热、低层增温增湿、中高层干冷对大气对流不稳定性增强的作用显著;对流有效位能（CAPE）、K指数、SI指数高值区边缘的强指数梯度区、对流抑制（CIN）的小值区以及较强的垂直风切变对大风冰雹的预报有重要的指示意义;雷达回波显示多单体风暴具有三体散射、弱回波区等冰雹回波特征,中层径向辐合和反射率因子核心的反复上升下降也是形成地面大风和冰雹的重要特征;四川盆地东部东北西南向山脉对冷空气的移动有阻挡作用,山脉之间的槽状地形为多单体风暴的持续发展保留了较大的空间,明月山南麓的地形起到了强迫抬升和触发的作用,由于地形的阻挡形成狭管效应,加强了下击暴流形成的地面大风,是形成11级大风的重要因素。     

基于Spark Streaming的实时流数据处理模型化研究与实现

通过研究与分析,选取Spark Streaming技术实现对P实时流数据的处理.同时,研究出一套模型化的方式,实现动态装配软件的执行过程;并通过具体的实例展示了两者结合后,在数据处理的易用性、性能及吞吐量方面,都得到了大幅提升.     

利用几何网络提取河网径流节点的方法研究

本文分析了河网径流节点的基本特征及分类,论述了基于ArcGIS水文分析模块提取河网径流的方法,并在此基础上提出了基于几何网络提取河网径流节点的方法.该方法提取得到的径流节点,除能表达其位置信息外,属性表中还记录了径流节点类型、汇流等级情况信息.实例表明该方法原理简单,易于操作实现,提取效果与实际地貌情况基本相符,可以广...     

Use of LiDAR-derived DEM and a stream length-gradient index approach to investigation of landslides in Zagros Mountains,Iran

This paper presents an approach to stream length-gradient index analysis to identify tectonic signatures. The graded profile of the Dez River in Zagros Mountains, Iran, indicates that the area has been tectonically disturbed, and it triggers landslide hazards. The high-gradient index shows that a steeper gradient could be potentially a signature for landslides identification. The digital surface models acquired by airborne LiDAR were used in this study to generate the HRDEM. Our result shows a great potential for improving landslide investigations by implementing stream length-gradient index derived from the HRDEM in conjunction with the landslide inventories data-set in the GIS environment. We also identified a correlation between the stream length-gradient index and the graded topographic profile with slopes and landslides. This empirical approach was verified by geodata analytics and landslide inventories data-set in conjunction with field observations. This study has identified the locations of high-gradient indices with susceptible to landslides.     

露天矿GPS卡车调度系统数据流处理方法

露天矿GPS卡车调度系统是数字矿山建设中的重要组成部分,是露天矿生产管理利用GPS／GIS技术提高生产效益的有效途径之一。本文根据露天矿GPS卡车调度系统的组成、工作原理和数据流交换模式,提出了基于数据回放条件下的装卸车时序匹配计算方法以及数据流处理的主要内容。抚顺西露天矿的实践证明,该计算方法是一种处理卡车调度系统数据流的有效且可行的办法。     

树状河系主流的自动推理

分析了不同类型河系的空间特征,对非网状河系以180°假设和锐角假设为基础,改进了自动确定河段流向的定量化决策表,当出现流向冲突时,遵守少数服从多数的原则。参考河段的流向、节点处分支河段的累计河段数和累计长度,能自动推理出树状河系的主支流关系。在此基础上,进一步研究了树状河系的编码方法,并用实例验证了所提出的算法。     

BIFoR FACE: Water–soil–vegetation–atmosphere data from a temperate deciduous forest catchment,including under elevated CO2

The ecosystem services provided by forests modulate runoff generation processes, nutrient cycling and water and energy exchange between soils, vegetation and atmosphere. Increasing atmospheric CO₂ affects many linked aspects of forest and catchment function in ways we do not adequately understand. Global levels of atmospheric CO₂ will be around 40% higher in 2050 than current levels, yet estimates of how water and solute fluxes in forested catchments will respond to increased CO₂ are highly uncertain. The Free Air CO₂ Enrichment (FACE) facility of the University of Birmingham's Institute of Forest Research (BIFoR) is the only FACE in mature deciduous forest. The site specializes in fundamental studies of the response of whole ecosystem patches of mature, deciduous, temperate woodland to elevated CO₂ (eCO₂). Here, we describe a dataset of hydrological parameters – seven weather parameters at each of three heights and four locations, shallow soil moisture and temperature, stream hydrology and CO₂ enrichment – retrieved at high frequency from the BIFoR FACE catchment.     

Long-term hydrological,biogeochemical, and climatological data from Walker Branch Watershed,East Tennessee,USA

In 1967, the original Walker Branch Watershed (WBW) project was established to study elemental cycling and mass balances in a relatively unimpacted watershed. Over the next 50+ years, findings from additional experimental studies and long-term observations on WBW advanced understanding of catchment hydrology, biogeochemistry, and ecology and established WBW as a seminal site for catchment science. The 97.5-ha WBW is located in East Tennessee, USA, on the U.S. Department of Energy's Oak Ridge Reservation. Vegetation on the watershed is characteristic of an eastern deciduous, second-growth forest. The watershed is divided into two subcatchments: the West Fork (38.4 ha) and the East Fork (59.1 ha). Headwater streams draining these subcatchments are fed by multiple springs, and thus flow is perennial. Stream water is high in base cations due to weathering of dolomite bedrock and nutrient concentrations are low. Long-term observations of climate, hydrology, and biogeochemistry include daily (1969–2014) and 15-min (1994–2014) stream discharge and annual runoff (1969–2014); hourly, daily, and annual rainfall (1969–2012); daily climate and soil temperature (1993–2010); and weekly stream water chemistry (1989–2013). These long-term datasets are publicly available on the WBW website (https://walkerbranch.ornl.gov/long-term-data/ ). While collection of these data has ceased, related long-term measurements continue through the National Ecological Observatory Network (NEON), where WBW is the core terrestrial and aquatic site in the Appalachian and Cumberland Plateau region (NEON's Domain 7) of the United States. These long-term datasets have been and will continue to be important in evaluating the influence of climatic and environmental drivers on catchment processes.     

Shenandoah Watershed Study-Virginia Trout Stream Sensitivity Study (SWAS-VTSSS): Stream water quality and hydrologic monitoring data for mid-Appalachian headwater streams

The Shenandoah Watershed Study (established in 1979) and the Virginia Trout Stream Sensitivity Study (established in 1987) serve to increase understanding of hydrological and biogeochemical changes in western Virginia mountain streams that occur in response to acidic deposition and other ecosystem stressors. The SWAS-VTSSS program has evolved over its 40+ year history to consist of a temporally robust and spatially stratified monitoring framework. Currently stream water is sampled for water quality bi-hourly during high-flow events at three sites and weekly at four sites within Shenandoah National Park (SHEN), and quarterly at 72 sites and on an approximately decadal frequency at ~450 sites within the wider western Virginia Appalachian region. Stream water is evaluated for pH, acid neutralizing capacity (ANC), base cations (calcium, magnesium, sodium and potassium ion), acid anions (sulphate, nitrate and chloride), silica, ammonium, and conductivity with a subset of samples evaluated for monomeric aluminium and dissolved organic carbon. Hourly stream discharge (four sites) and in-situ measurements of conductivity, water and air temperature (three sites) are also measured within SHEN. Here we provide an overview and timeline of the SWAS-VTSSS stream water monitoring program, summarize the field and laboratory methods, describe the water chemistry and hydrologic data sets, and document major watershed disturbances that have occurred during the program history. Website links and instructions are provided to access the stream chemistry and time-series monitoring data in open-access federal databases. The purpose of this publication is to promote awareness of these unique, long-term data sets for wider use in catchment studies. The water chemistry and hydrologic data can be used to investigate a wide range of biogeochemical research questions and provide key inputs for models of these headwater stream ecosystems. SWAS-VTSSS is an ongoing program and quality assured data sets are uploaded to the databases annually.     

Effects of changes in canopy interception on stream runoff response and recovery following clear-cutting of a Japanese coniferous forest in Fukuroyamasawa Experimental Watershed in Japan

Understanding changes in evapotranspiration during forest regrowth is essential to predict changes of stream runoff and recovery after forest cutting. Canopy interception (Ic) is an important component of evapotranspiration, however Ic changes and the impact on stream runoff during regrowth after cutting remains unclear due to limited observations. The objective of this study was to examine the effects of Ic changes on long-term stream runoff in a regrowth Japanese cedar and Japanese cypress forest following clear-cutting. This study was conducted in two 1-ha paired headwater catchments at Fukuroyamasawa Experimental Watershed in Japan. The catchments were 100% covered by Japanese coniferous plantation forest, one of which was 100% clear-cut in 1999 when the forest was 70 years old. In the treated catchment, annual runoff increased by 301 mm/year (14% of precipitation) the year following clear-cutting, and remained 185 mm/year (7.9% of precipitation) higher in the young regrowth forest for 12–14 years compared to the estimated runoff assuming no clear-cutting. The Ic change was −358 mm/year (17% of precipitation) after cutting and was −168 mm/year (6.7% of precipitation) in the 12–14 years old regrowth forest compared to the observed Ic during the pre-cutting period. Stream runoff increased in all seasons, and the Ic change was the main fraction of evapotranspiration change in all seasons throughout the observation period. These results suggest that the change in Ic accounted for most of the runoff response following forest cutting and the subsequent runoff recovery in this coniferous forest.