固态存储雨量计与虹吸式雨量计降水资料初步对比分析

通过对JDZ05型、OTT Pluvio称重式雨量计与虹吸式自记雨量计不同时段的降水量数值和误差进行对比分析。结果表明,JDZ05翻斗式雨量计和称重式雨量计存在一定误差,但多数数据精度满足规范的要求。(1)JDZ05型、OTT Pluvio称重式雨量计汛期降水量一般均少于虹吸式;(2)两种雨量计与虹吸式雨量计日降水量的平均相对误差一般在0.1%~4%之间;(3)两种雨量计短历时降水平均相对误差符合规范要求的比例随着降水历时增长并趋于稳定,一般在63%~91%之间,称重式雨量计一般大于翻斗式雨量计;(4)翻斗式雨量计与虹吸式自记雨量计相比,日降水量偏多、偏少日数基本相当,称重式雨量计大多偏多。     

称重式与虹吸式雨量计观测雨量精度对比分析

为满足水文资料即时整编的需要,加快水文监测自动化建设步伐,准确了解自动化雨量计监测的合理性,以北京市降雨资料为研究对象,选取2016—2018年26个站点的雨量数据,分别从年降水量、降水日数、日降水量、典型降水过程4个方面,对称重式雨量计与虹吸式雨量计的观测雨量进行对比分析,分析结果表明,两者的观测序列具有较好的相关性与一致性,去除通信不佳造成称重式雨量计缺测的情况,两者的相关系数均值达0.94,平均绝对误差和均方根误差均值分别为-0.15、2.35,符合《降水量观测规范》(SL 21—2015)要求的站点达88%,因此称重式雨量计可以较好地替代虹吸式雨量计,表明自动化雨量计监测具有一定的可靠性。     

大伙房水文站自动测报与人工观测降雨量对比分析

文章通过对FDY-05-02型翻斗式雨量计和普通式雨量计测量结果进行对比分析,选取大伙房水文站2010～2016年5～10月降雨量进行误差分析,结果表明:翻斗式雨量计与普通式雨量计年降雨量误差为1%;翻斗式雨量计月平均降雨量整体比普通式雨量计偏大,5月和10月降雨误差百分率误差小于1%,其余五个月降雨量误差百分率在1%～2%之间;日降雨量以人工观测降雨量为标准,系统偏差在0～40. 5%之间;并对其误差进行了详细分析。     

虹吸式雨量计与称重式雨雪量计降水资料对比分析

文章通过对壶流河水库水文站2017年汛期使用的虹吸式雨量计和称重式雨雪量计的降水量数据和误差进行统计对比分析,结果表明由于两种设备工作原理的差异,在观测记录过程中存在一定误差,但多数误差在规范的允许误差范围内,称重式雨雪量计汛期观测值较虹吸式雨量计偏小。通过汛期阶段的使用,称重式雨雪量计相较于传统的人工监测方式有这不可比拟的优势。     

JEZ02型融雪式雨量计在平凉市泾渭河流域的适用性研究

以平凉市泾渭河流域典型黄土高原地区为例,对研究区域内的45处JEZ02型融雪式雨量计降水量数据进行分析,对其适用性进行研究.在对区域内雨量站点数据分类收集的基础上,利用水文资料整编系统HDP5.0、甘肃省水文测验系统等软件进行整编,通过水文统计学方法比测分析,结果表明:①JEZ02型融雪式降水量数据受限于提取方式与数据...     

翻斗式雨量计运作过程误差分析

翻斗式雨量计是一种观测自然界降雨量的设备,它将一定的降雨量转换为开关信息输出,其不同的误差来源对雨量数据采集精度具有不同程度的影响。如何减小雨量数据采集误差,对水资源利用、洪水预报、水文资料整编等工作具有重要意义。通过对翻斗式雨量计进行误差分析,提出通过调节翻斗感量,并根据常年降雨强度统计数据,以及不同雨强下的滴定结果,将翻斗式雨量计应用到更适合的区域,从而减小翻斗式雨量计的降雨量观测误差。     

增大适应雨强范围的新型翻斗式雨量计设计

分析了翻斗式雨量计的动作过程误差随雨强增大而增大的关系,设计了一种增大适应雨强范围的分流式翻斗式雨量计,并在理论上对分流式翻斗式雨量计和现有的单翻斗式雨量计的适应雨强范围进行了比较。结果表明:分流式翻斗式雨量计可解决翻斗式雨量计因误差随雨强增大而增大导致的对雨强适应性不强的问题,增大翻斗式雨量计的适应雨强范围,既能保证大雨强时次雨量的计量精度,又能保证小雨强或微雨时的降雨计量次数。     

陆水水库（坝上）站两种不同分辨率雨量计观测数据对比分析

为提高降水量观测成果精度,且为防汛测报工作提供有力的数据支撑,基于陆水水库(坝上)站使用的两种不同分辨率雨量计同期测得2017～2019年降水观测资料,分别从仪器的结构性能、年降水量、月降水量、日降水量、降水日数等方面进行了对比分析,研究了不同分辨率的雨量计对雨量观测结果的影响程度。分析结果表明:在雨强较大时,分辨率为0.5 mm的20 cm JDZ05-1型翻斗式雨量计雨量观测数据代表性较好,反之,分辨率为0.1 mm的JFZ-01型数字雨量计雨量观测数据代表性较好。     

称重式雨量计与虹吸雨量计降水数据对比分析

选用2019年OTT型称重式雨量计与虹吸雨量计5～9月降水数据采用日量、月量、场次、极值4方面进行对照,通过误差分析研究两套设备之间是否存在差异,以合格率判定称重式雨量计观测降水是否准确,为新设备的普及提供数据支持。     

虹吸式雨量计的误差分析

虹吸式雨量计是利用虹吸原理进行工作,连续记录以毫米的单位的液态降水量,并可测定雨强和降雨起迄时间的计量仪器。本文主要分析虹吸式雨量计的计量误差。1 虹吸式雨量计的结构 虹吸式雨量计主要由承水部分、虹吸部分和自记部分组成(图1)。承水部分由一个内径为200mm的承水器和大、小漏斗组成,     

Quantifying the Uncertainty Interaction Between the Model Input and Structure on Hydrological Processes

Input error is one of the main sources of uncertainty in hydrological models. It mainly comes from the uncertainty of precipitation data, which is caused by inaccurate measurement at the point scale and imperfect representation at the regional scale. The structural error of the hydrological model is dependent on the input, and the uncertainty interaction between the model input and structural will increase the cumulative error of the hydrological process. Therefore, the objective of this study is to investigate the impacts of the uncertainties of rain gauge station input levels and hydrological models on flows with different magnitudes by setting nine input levels of rain gauge stations using three hydrological models (i.e., HyMod, XAJ and HBV). The variance decomposition method based on subsampling was used to dynamically quantify the contribution rates of rain gauge station input levels, hydrological models, and their interaction to the runoff simulation uncertainty. The results show that different rain gauge station input levels and hydrological models dynamically affected the hydrological simulation due to an uneven spatiotemporal distribution of precipitation. Moreover, the simulation accuracy was poor at low flow but better at high flow. Increasing the number of rainfall stations input under a certain threshold could significantly improve the hydrological simulation accuracy. In addition, the contributions of the uncertainties of the rain gauge station input levels and its interaction with the hydrological model to runoff were significantly enhanced in the flood season, but the contribution of the hydrological model uncertainty was still dominant. The results of this study can provide a decision-making basis and scientific guidance for the management and planning of water resources within basins under the influence of a changing environment.

     

Empirical and theoretical assessment of the wind induced error of rain measurement

The computational fluid dynamics and the simulation of precipitation trajectories was applied to assess the wind induced error of precipitation measurements using the Hellmann gauge. The results agree well with the empirical correction formula for the same gauge type derived from field data obtained from inter comparison measurements of paired Hellmann elevated and pit gauges in Les Avants (982m asl), Switzerland. This means that correction procedures can be derived for any type of gauge using the theoretical approach instead of the empirical one. The computational and empirical results fit a model which uses the intensity of rain as an independent variable and produces a set of one parameter curves (wind speed) with increasing threshold value of intensity for increasing wind speed. Below the threshold values the wind-induced error increases quickly with decreasing intensity of precipitation; above it the increase is slow.     

双层翻斗式雨量计翻斗特性的试验和模拟分析

为探究双层翻斗式雨量计(DTBR)减小计量误差的作用机理以及进一步提高DTBR的计量精度,利用试验和数值模拟相结合的方法,通过高速摄像掌握翻斗翻转特性,结合动网格和流体体积法(VOF)模型对DTBR上层翻斗的翻转过程进行流体动力学模拟,并进一步优化了DTBR的结构设计。结果表明:DTBR依靠上层翻斗,通过中间漏斗将自然降水强度下的出流量稳定在1.01.g/s左右注入下层计量翻斗,可明显降低降水强度对雨量计计量误差的影响,且在高降水强度下的效果更加明显；中间漏斗在不同降水强度下的流量均稳定在1.g/s(等效1.91 mm/min降水强度)左右,在DTBR标定中,可考虑只对下层的计量翻斗进行1.91 mm/min降水强度的标定,即可满足DTBR的计量要求；中间漏斗存在震荡出流过程,出流最大可达2.g/s左右；降低上层翻斗的中轴高度可在一定程度上稳定中间漏斗的出流过程。     

基准降水对GPM数据精度的影响——以南京“20170610”极端降水事件为例

现有文献多采用两种途径生成评价GPM等卫星遥感反演降水数据精度的基准资料：站点基准降水和插值基准降水，然而，关于基准资料生成方法对卫星降水数据精度的影响以及应优先采纳哪种基准资料尚缺乏深入研究。因此，本文以南京“20170610”极端降水事件为例，利用地面稠密雨量站的观测资料，设计了不同地表雨量站点密度下的随机抽取试验，解析了不同地表基准降水条件下IMERG Early、IMERG Late和GSMaP NOW三种GPM数据的精度特征。结果发现，基准降水对GPM数据精度的影响与雨量要素、数据类型、指标类型、站点密度有关。进一步以高超密度站点插值降水作为“真实”降水，量化了不同站点密度条件下两种基准降水的误差，发现对于24 h累积雨量和逐小时降水过程，存在一定的雨量站点平均密度临界值。若雨量站点密度高于该临界值，以插值降水为基准评价GPM数据的精度更合理，否则采用插值降水和站点降水为基准均可。本文研究深化了对GPM降水数据误差特性的认识，可为合理选取评估卫星降水数据的地表基准数据生成方法提供参考。     

风场对雨量计收集降水影响的流体动力学研究

为研究风场对雨量计收集降水精确性的影响,对单个雨量计以及Alter和Tretyakov防风圈的风场特性进行数值模拟。结果表明:单个雨量计中心线上速度最大增比达19%,出现在器口上8 cm左右;加入Alter和Tretyakov防风圈可有效减少雨量计器口上方的风速大小和梯度:Alter防风圈使中心线上最大速度减小11%,并在主流方向90°位置产生两个强烈涡旋区域,破坏到达雨量计收集区域的流场强度和均匀性,使其流向较为紊乱,可能对降雪的收集产生不利影响;Tretyakov防风圈使雨量计中心线上最大速度减小7%,并由于叶片特殊勾角结构,使到达雨量计降水收集区域的流向更一致,更有利于对降雪的收集。Alter防风圈对风速大小和梯度的减弱程度优于Tretyakov防风圈,但低风速下Tretyakov防风圈在雨量计器口上方的涡核心区域范围小于Alter防风圈,更有利于降水收集。Tretyakov防风圈的直径比Alter防风圈小约0.3 m,如对Tretyakov防风圈进行改进,可增加其直径以及叶片个数来规避高风速下Tretyakov防风圈叶片产生的涡核心区域对雨量计收集区域的影响。对Alter防风圈改进,可参考Tretyakov防风圈,增加叶片倾斜角,以提高降水收集率。     

JDZ-1型固态存储雨量器降水量误差成因分析

对JDZ-1型固态存储雨量器与虹吸自记雨量计平行观测资料进行了系统分析,分析了两者存在误差的影响因素。对JDZ-1型固态存储雨量器在北方地区使用过程中存在的问题提出了解决方法,以保证和提高JDZ-1型固态存储雨量器资料质量。     

Quality control of rain data used for urban runoff systems

When improving software packages such as MOUSE and SAMBA for designing sewers and storage basins, and simulating overflows and flooding the quality of the input becomes important The essential input to these modelling tools are the historical rain series. This paper presente the procedures for collection and quality control of rain data from a network of tipping bucket rain gauges in Denmark carried out by the Danish Meteorological Institute. During rain, the RIMCO gauge counts the number of tips (each of 0.2 mm of precipitation) every minute. The quality control of the rain data includes an automatic and a manual bit marking, where the automatic control basically is pointing out minutes with extreme intensities. In the manual control, the maximum intensities as well as the daily totals of precipitation are inspected, using weather charts, intensity plots and precipitation sums of nearby Hellmann gauges. Shortcomings and improvements of the quality control are discussed. Although, it is possible to improve the efficiency of the quality control, long term corrections will always be necessary.     

Nested Augmentation of Rainfall Monitoring Network: Proposing a Hybrid Implementation of Block Kriging and Entropy Theory

One of the most influential environmental variables is rainfall which has significant effect on water resources management, agricultural development, hydrology, and climate change studies. Due to high spatiotemporal variability of rainfall, its monitoring network design can be considered as a useful tool to improve the efficiency of recorded rain gauge stations within the study area. In this study, a new methodology of augmentation of rain gauge network is developed using coupled Block Kriging (BK) and entropy theory methods. In the proposed method, a nested approach of a two-stage positioning of rain gauge stations has been demonstrated. In the first stage, large-scale or fast positioning was done in which the optimal number of candidate blocks was identified. Then, local scale or fine-tuned positioning was done in the second stage. In this stage, to develop the network, accurate locations of rain gauge stations in each block are determined. Besides the main point of this paper, the effect of two kriging estimators, BK and Ordinary Kriging (OK), on the developed network has been investigated and compared. The study area is the Namak Lake watershed with various climates and altitudes. To assess the performance of the optimal rainfall network, three diagnostics were utilized; spatial distribution of annual precipitation, Estimation Error Variance (EEV) maps and histograms. Based on the results, 30 (more than 30% percent of the current stations) rain gauge stations have been proposed scattered over the watershed. Evaluation of the results has shown that the augmented rain gauge network proposed by the BK method outperformed dramatically that of the OK method. EEV maps and also statistical analysis of EEV values confirms the EEV value reduction of almost 25% in augmented network, as well.

     

The effect of climate change on urban drainage: an evaluation based on regional climate model simulation.

That we are in a period of extraordinary rates of climate change is today evident. These climate changes are likely to impact local weather conditions with direct impacts on precipitation patterns and urban drainage. In recent years several studies have focused on revealing the nature, extent and consequences of climate change on urban drainage and urban runoff pollution issues. This study uses predictions from a regional climate model to look at the effects of climate change on extreme precipitation events. Results are presented in terms of point rainfall extremes. The analysis involves three steps: Firstly, hourly rainfall intensities from 16 point rain gauges are averaged to create a rain gauge equivalent intensity for a 25 x 25 km square corresponding to one grid cell in the climate model. Secondly, the differences between present and future in the climate model is used to project the hourly extreme statistics of the rain gauge surface into the future. Thirdly, the future extremes of the square surface area are downscaled to give point rainfall extremes of the future. The results and conclusions rely heavily on the regional model's suitability in describing extremes at timescales relevant to urban drainage. However, in spite of these uncertainties, and others raised in the discussion, the tendency is clear: extreme precipitation events effecting urban drainage and causing flooding will become more frequent as a result of climate change.     

湘江流域 TRMM 降水数据精度检验

数据精度检验是卫星遥感降水数据应用中的关键问题之一。目前对TRMM数据精度检验多以偏差和相关性分析等方法为主,对不同雨量等级的估计检验比较缺乏。针对湘江流域,引入模糊综合评分方法以解决不同雨量等级降水估计的检验,同时利用泰森多边形法、模糊综合评分方法、相关系数法和散点斜率法,以研究区内14个气象站点实测降水数据为"真值",对TRMM 3B42降水数据在日、月尺度分别进行了定性和定量精度检验。结果表明:研究区TRMM 3B42降水数据在月、日尺度上相关系数分别达到了0.93、0.48,前者偏差值Bias比后者低84%,精度更优;在不同降水量级的预测中,精度由好到差依次为小雨、暴雨、大雨、中雨,其中小雨预报精度最好,达到良好水平,其他雨量级预报精度为中等水平。