Use of Predictive Weather Uncertainties in an Irrigation Scheduling Tool Part II: An Application of Metrics and Adjoints

We apply predictive weather metrics and land model sensitivities to improve the Colorado State University Water Irrigation Scheduler for Efficient Application (WISE). WISE is an irrigation decision aid that integrates environmental and user information for optimizing water use. Rainfall forecasts and verification performance metrics are used to estimate predictive rainfall probabilities that are used as input data within the irrigation decision aid. These input data errors are also used within a land model sensitivity study to diagnose important prognostic water movement behaviors for irrigation tool development purposes simultaneously performing the analysis in space and time. Thus, important questions such as “how long can a crop water application be delayed while maintaining crop yield production?” are addressed by evaluating crop growth stage interactions as a function of soil depth (i.e., space), rainfall events (i.e., time), and their probabilistic uncertainties. Editor’s note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.     

淮南市降水化学组成特征与来源分析

2013—2014年,逐次采集淮南城市大气降水样品,对其离子化学组分进行分析测试,并利用酸度分析、中和因子和富集系数等方法对其酸碱物质平衡和离子来源进行了分析。化学组分分析结果表明,淮南城市降水pH为6.23~7.03,雨量加权平均值为6.68,整体上降水没有呈现酸化,大部分酸性物质能被碱性物质中和。主要阴离子为SO_4~(2-)、NO_3~-,雨量加权平均值分别为147.02、62.16μeq/L,两者分别占阴离子总浓度的60.3%、25.3%;主要阳离子为Ca~(2+)、NH_4~+,雨量加权平均值分别为126.42、96.43μeq/L,分别占阳离子总浓度的44.9%、34.3%。利用富集系数法计算结果表明,SO_4~(2-)、NO_3~-主要来源于人为活动排放,Cl~-主要为海洋输入,而Ca~(2+)、Mg~(2+)、K~+则主要来自陆源输入和人为活动。     

1961~2015年西南地区降水及洪涝指数空间分布特征

利用西南地区98个气象站连续完整的日降水序列数据，整合降水强度、持续性指数及等级指数形成降水指数体系并研究该区域降水及洪涝指数的空间分布特征，得到以下主要结论：（1） 1961~2015年，西南地区年降水量（PRCPTOT）与极端降水量（R95PTOT）都呈现出“东多西少、南多北少”的分布形态；持续降水日数（CWD）则表现为“南高北低、西高东低”的分布格局。区域多年平 均PRCPTOT、R95PTOT、CWD分别以-13.12 mm/10 a、1.34 mm/10 a、-0.29 d/10 a的速率变化。（2）西南地区不同等级降水日数具有相似的空间分布特征，均呈现出“南高北低、东高西低”的分布形态。（3）西南地区洪涝强度指数呈由东北向西南递减的分布特征；降水总量越多的地区，洪涝强度反而越低，主要由于单站洪涝强度表征的是降水的波动情况，降水量越多波动越不明显。21世纪以来，该 地区洪涝等级以重级为主，2010年以来连续多年出现特重级洪涝。此外，洪涝强度越大，区域性年度灾害等级越高。该研究对于掌握西南地区极端气候变化规律，从而服务于防灾减灾具有一定的理论意义。     

智能家电的低待机功耗研究

从智能家电待机工作状态入手,分析电器产品中参与待机工作的各部分电路原理,提出降低潜在功耗设计思路和计算方法,从家电设计研发阶段对待机功耗进行控制,同时对待机功耗精确测量方法关键点进行解读以控制低功耗测试不确定度,有助于低待机功耗设计和测量的标准化和规范化。     

Does the Temporal Resolution of Precipitation Input Influence the Simulated Hydrological Components Employing the SWAT Model?

This study aimed to evaluate the influence of sub‐daily precipitation time steps on model performance and hydrological components by applying the Green and Ampt infiltration method using the Soil and Water Assessment Tool (SWAT). Precipitation was measured at a resolution of 0.1 mm and aggregated to 5‐, 15‐, 30‐, and 60‐min time steps. Daily discharge data over a 10‐year period were used to calibrate and validate the model. Following a global sensitivity analysis, relevant parameters were optimized through an automatic calibration procedure using SWAT‐CUP for each time step. Daily performance statistics were almost equal among all four time steps (NSE ≈ 0.47). Discharge mainly consisted of groundwater flow (55%) and tile flow (42%), in reasonable proportions for the investigated catchment. In conclusion, model outputs were almost identical, showing simulations responded nearly independently of the chosen precipitation time step. This held true for (1) the selection of sensitive parameters, (2) performance statistics, (3) the shape of the hydrographs, and (4) flow components. However, a scenario analysis revealed that the precipitation time step becomes important when saturated hydraulic conductivities are low and curve numbers are high. The study suggests that there is no need in using precipitation time steps <1 h for lowland catchments dominated by soils with a low surface runoff potential if daily flow values are being considered. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series.     

烟气脱硫溶液中硫酸根的去除

分别采用石灰乳化学沉淀法和低温结晶法去除烟气脱硫溶液中的SO42-。实验结果表明：在室温、CaO溶液质量分数25%的条件下，石灰乳化学沉淀法对SO42-的去除率仅为59.51%，且向溶液中引入了Ca2+，产生的硫酸钙固体废物难以再生利用；采用低温结晶法处理烟气脱硫溶液，在结晶温度7 ℃、结晶时间3 h、NaOH加入量34.8 g/L的条件下，SO42-的去除率为82.04%、滤液中的ρ（Na+）为3.88 g/L。在现场工业应用试验中，采用低温结晶法去除烟气脱硫溶液中的SO42-，平均SO42-的去除率可达70.00%以上，滤液中的ρ（Na+）小于15.00 g/L。该法可有效抑制烟气脱硫溶液中SO42-含量的增加。     

30MHz-1000MHz显示器辐射骚扰测试及其不确定度评定

本文以显示器辐射骚扰测试为例对10米半电波暗室的辐射骚扰试验进行不确定度评定。并与相应标准进行比较，确认该辐射测试系统的测量结果是可信的。     

中国西南酸雨区降水化学特征研究进展

西南酸雨区为我国主要酸雨沉降区,且是全球三大喀斯特集中分布区之一.本文将该区9个地点的降雨资料进行了总结、整理和分析,数据包括pH值和主离子成分(Cl~-、SO_4~(2-)、NO_3~-、Ca~(2+)、NH_4~+、Mg~(2+)、K~+、Na~+).该地区降雨中的主要阴离子为SO_4~(2-)和NO_3~-,主要阳离子为Ca~(2+)和NH_4~+.与我国其它地区相比,其酸性离子、碱性离子和总离子浓度均普遍高于东南地区、而低于我国北方地区.西南酸雨区主要以pH值为4.5~5.6的弱酸性降雨为主,占总降雨频次的58%左右.根据酸、碱性离子的相关性、中和因子等分析结果,该区雨水中的酸性物质可能受到了碱性离子的中和作用,其中起主要中和作用的离子为Ca~(2+)和NH_4~+.将该区雨水pH值和酸、碱性离子浓度与我国其它地区进行对比研究发现,西南酸雨区降雨受到的中和作用要强于东南地区,但弱于北方地区的降雨.通过对西南酸雨区降雨中主要离子来源的分析和估算,降雨中的酸性离子SO_4~(2-)和NO_3~-主要来自于人为污染;99.7%的Ca~(2+)和84.0%的Mg~(2+)为陆源贡献,这可能与西南地区碳酸盐岩广泛分布有关.     

水泥窑协同处置生活垃圾焚烧飞灰的汞排放特性及管控措施探讨

生活垃圾焚烧飞灰资源化利用主要途径之一是作为生产水泥原料。飞灰中富集了高浓度的汞、镉、铅等重金属。新型水泥窑的工艺特点导致高挥发性的汞无法固化在水泥熟料中,汞主要随烟气外排。当水泥窑处置飞灰规模较大、飞灰中汞含量较高时,如不采取控制措施,会导致水泥窑排放烟气中汞浓度超过标准限值。分别从机理分析、数据统计演算及实际检测结果多方面进行了验证,提出应加强对水泥窑协同处置飞灰过程中汞污染的认识及监督管理,探索有效的汞排放控制途径,确保汞排放达标。     

Sensitivity of Precipitation Statistics to Urban Growth in a Subtropical Coastal Megacity Cluster

This short paper presents an investigation on how human activities may or may not affect precipitation based on numerical simulations of precipitation in a benchmark case with modified lower boundary conditions, representing different stages of urban development in the model. The results indicate that certain degrees of urbanization affect the likelihood of heavy precipitation significantly, while less urbanized or smaller cities are much less prone to these effects. Such a result can be explained based on our previous work where the sensitivity of precipitation statistics to surface anthropogenic heat sources lies in the generation of buoyancy and turbulence in the planetary boundary layer and dissipation through triggering of convection. Thus only mega cities of sufficient size, and hence human-activity-related anthropogenic heat emission, can expect to experience such effects. In other words, as cities grow, their effects upon precipitation appear to grow as well.