雨量器(计)安装不水平造成的测量误差分析及对策

降水量是气象台站重要观测项目之一。目前，大部分基层台站用于降水量观测的仪器主要靠雨量器、翻斗式遥测雨量计和虹吸式雨量计３种。《地面气象观测规范》规定：雨量器在安装和使用过程中都必须水平，以保证所测降水数据的准确性。但在实际工作中，由于各种原因往往会使器口倾斜。尤其是雨量器结构粗糙且每次观测都要取下承水器，稍不注意就会发生倾斜。那么雨量仪器安装不水平对测量水有何影响呢？大部分观测员都认为会比实际雨量偏小，其实不尽然。本文试图通过对不同降水情况下的误差进行分析，同时提供一些消除误差的方法供参考。为了…     

翻斗式遥测雨量计的调试和维修

翻斗式遥测雨量计,是我国新设计定型的雨量自记仪器,这种仪器既可作液态降水的定时测量,又能作降水量的连续记录,同时采用有线遥测,观测使用方便,测量精度为0.1毫米,在降水强度不大于每分4毫米时,误差不大于±4%。能满足气     

浅析遥测雨量计超差原因

降水观测常用仪器是雨量器和遥测雨量计。在使用期间常会出现遥测读数和雨量器读数有偏差 ,有时超出仪器本身允许的误差范围 ,这种现象称为超差。判断仪器是否超差 ,首先进行差值计算。即 :　差值 =(排水量 -遥测雨量 ) /排水量× 1 0 0 %如果差值在± 4 %之内 ,则为正常 ;否则     

虹吸式雨量计的常见故障及其排除方法

虹吸式雨量计是气象台站普遍使用的用于连续自动记录降水变化的仪器。目前多数台站使用的是承雨口面积 314ｃｍ2 的虹吸式雨量计 ,每 10ｍｍ雨量虹吸一次。在测定较小雨量时其效果较好 ,但在降水强度较大或降水时间较长时 ,其误差大、故障多 ,较压、温、湿等自记仪器易出故障。《地面气象观测规范》中 ,对虹吸式雨量计安装与使用做了较详细的讲解 ,但由于多方面原因 ,虹吸式雨量计使用中仍有一些故障发生。该文对房县站虹吸式雨量计使用过程中出现的故障进行了分析 ,并找出了故障的成因及相应的排除方法。1　主要故障及其排除方法多年来 ,房…     

对遥测雨量计使用的一点看法

我站从去年开始使用遥测雨量计,由于是新仪器,对其性能了解不多,但通过一年的使用,对记录认真的观察和分析,基本上了解了它的性能和在工作中存的利弊。下面就谈谈这个问题:气象站从没有虹吸雨量计发展到有虹吸雨量计;又从使用虹吸雨量计到使用遥测雨量计。我们看到在记录降水的仪器上     

几种雨量观测方式比对试验分析

为进一步了解不同雨量观测方式对降水测量的影响,在中国气象局大气探测试验基地进行了几种雨量观测方式的比对试验。本文利用该试验的观测资料,分析了不同雨量计及其不同安装方式对降水测量的影响,并分别给出了各雨量计的测量值。结果表明:降水测量与雨量计的安装方式极其相关,坑式安装测量的雨量值最大,其余依次为双栅、防风圈和平地安装(呈水口高出地面70cm);当前业务观测方式测得的降雨量偏小;降雪测量受风场的影响比液态降水测量更显著。     

Parsivel激光雨滴谱仪观测降水中异常数据的判别及处理

2009年利用Parsivel激光雨滴谱仪连续观测太湖地区自然降水,发现对流云降水采样的粒子谱数据常常包含有少数异常高、低数据.从Parsivel激光雨滴谱仪的测量原理出发,分析了产生测量误差的原因.然后依据3σ准则(莱以特准则)对采集的一次对流云降水粒子谱数据进行分析,对其是否存在粗大误差进行判别和消除.结果表明:异常数据即为仪器测量的粗大误差,消除误差后的数据在表征降雨量、雷达反射率因子等降水特征量时更加接近于仪器自身输出值.同样地将此方法用来分析层状云降水,有利于消减仪器测量中粒子重叠所造成误差.     

称重雨量数据处理卡尔曼滤波应用

降雨量的测量,目前业务上应用较为广泛的是翻斗式雨量计,它只能测降雨,对于冰雹、降雪等固态降水的测量采用人工观测为主,称重式雨量计与翻斗式雨量计相比,其优势在于能实现所有类型降水的全天候自动化观测。本研究随机选择了一天无降水数据确定了滤波参数Q和R(过程噪声方差和观测噪声方差),根据确定的滤波参数,随机选择了无降水(2016年4月3日)和有降水(2015年7月21日、2015年8月7日)日采用卡尔曼滤波,并结合翻斗雨量传感器数据进行验证,结果表明,本研究确定的滤波参数采用卡尔曼滤波后能够有效去除称重雨量中的噪声,使滤波后的曲线变得平稳光滑,减小了数据的抖动频率和误差。     

SL1型翻斗雨量计的结构和使用(上)

SL_1型翻斗式遥测雨量计是气象台站(哨)、水文、农林、科研等部门用以测量及连续记录液体降水量、降水强度和降水起迄时间的一种有线遥测雨量计(见封底照片)。其承水器口的直径为200毫米,允许误差±0.3毫米;降水强度的测量范围,不大于4毫米/分,最小分度为0.1毫米;测量精度在10毫米以内为     

基于漂移克里金融合雷达、雨量计定量估测降水研究

文中介绍了一种新的融合雷达和雨量计数据开展定量估测降水研究的空间信息统计学方法—Kriging with external drift(KED)方法。该方法能很好地融合高精度、低时空分辨率的雨量计数据和低精度、高时空分辨率的雷达数据进行插值。通过变异函数描述降水场的空间结构信息,能够充分利用数据间的空间相关性,来改进估测精度和提高处理速度。利用其优良的数学特性,以期在定量估测降水业务研究上进行新的探索和尝试。选用湖南省有代表意义的3次降水过程资料,通过雷达直接估测降水（RAD）、变分校准（VAR）以及KED 3种方法,分别与雨量计测量值进行对比分析,选用代表站进行交叉验证结果均表明：RAD的均方差、绝对误差、相对误差最大,VAR次之,而KED最小。KED估测的结果与雨量计测量降水最为接近,估测效果最好;3种方法与雨量计实测值计算一定范围的误差频率,KED估测值具有最小的均方差和最小的标准差,且误差分布相对集中在0值附近,斜度和峰度最佳,试验证明该方法不仅能提高降水估测精度,且优于其他方法,VAR均方差次之,RAD均方差效果相对较差。联合雷达、雨量计估测降水的实质是把雷达估测值与雨量计测量的结果相融合,以雨量计来校准雷达估测值,保留了雷达探测到降水的中、小尺度精细特征。校准后的雨量场数值接近雨量计测值,而且能够准确反映雷达测得的降水分布形式。     

区域自动站雨量资料质量控制方法及应用

针对翻斗式雨量计测量地面降雨量时出现误差的原因,介绍了石家庄市区域自动站雨量资料质量控制系统流程、有关质量控制技术及最终数据的输出。提出均值与范围值检查方法,并将时间一致性与内部一致性检查纳入空间一致性检查过程中。该系统人机交互界面友好,自动化程度高,能较好地检出自动站中雨量资料的异常值,保证了区域自动站雨量资料在决策及公共气象服务中的准确、及时和可视性。     

Optimization of the raingauges for a representative all-India and subdivisional rainfall series

Summary An objective approach similar to the forward selection of independent variables in the multiple linear regression has been attempted to optimize the network of raingauges for the summer monsoon rainfall (June–September total) series (1871–1984) of India as well as its 29 selected meteorological subdivisions prepared involving the data of 306 raingauges. For the all-India monsoon rainfall series twenty seven gauges entered the selection whose mean showed the correlation coefficient (CC) of 0.9869. Keeping in view the difficulties of getting data from all the 306 gauges, 35 India Meteorological Department (IMD) gauges with mean showing CC of 0.9898 have been identified for updating this series. The constructed all-India monsoon rainfall series for the period 1871–1992 using 35 selected observations is presented. It was interesting to note that the set of 35 gauges selected for the monsoon total has shown equally promising results for the all-India monsoon monthly (June–September) as well as the annual rainfall series.For the 29 subdivisional monsoon rainfall series, however, in total 188 IMD-gauges (62% of the total of 306 gauges) entered the selection. For 17 subdivisions the CC exceeded 0.98, for 3 subdivisions it varied between 0.97 and 0.98, for 5 subdivisions between 0.96 and 0.97 and for the remaining 4 subdivisions between 0.90 and 0.94. They showed equally encouraging results for the monsoon monthly and annual rainfall series for the different subdivisions.Limitations and implications of the optimization technique are also briefly discussed.With 9 Figures     

Parsivel与LNM激光雨滴谱仪降水观测的差异

为研究Parsivel与LNM两种激光雨滴谱仪观测性能的差异,通过分析北京南郊观象台试验场地的两台激光雨滴谱仪2014年7—11月(北方雨季条件下123天)的观测数据,并辅以同期的人工观测作为参考标准,将上述两种设备的累积降水量、起止时间、粒子采样信息等采集数据进行对比。分析结果表明:LNM激光雨滴谱仪较Parsivel激光雨滴谱仪的反映时间短,总是提早观测到降水现象的发生。Parsivel激光雨滴谱仪粒子等级信息较为丰富,同一降水过程中,Parsivel输出的粒子直径比LNM大。在降水量方面,两台设备与翻斗雨量计的结果基本一致,但累积降水量大于10mm时,LNM累积降水量的输出值明显大于Parsivel。     

Modelling the spatial and temporal distribution of rainfall intensity at local scale

Summary Accurate estimates of rainfall intensity distribution with high temporal and spatial resolution are necessary in most urban hydrological studies, such as planning, simulation or control of sewer networks. Traditionally, these data are obtained from intensity-duration-frequency (IDF) curves at sites with long rainfall intensity time-series, however, little attention is given to the spatial features of precipitation. In this paper, a mathematical model of a local scale storm that takes account of the spatial variability of rainfall and rain-cell movement is proposed. The model has been calibrated with a dense network of raingauges and a long rainfall intensity timeseries (60 years) and its parameters have been calculated for convective storms of return periods up to 15 years with their most frequently-observed rain-cell velocities (1 to 4 m/s).This work has been supported by the DGICYT, Project NAT91-0596.With 6 Figures     

Rainfall fluctuations over Italy and their association with solar activity

Summary Selected records from hundreds of raingauges located along the river basins of the largest Italian rivers, throughout the whole of Italy, show a fairly similar interannual variability. Analysis of the historical time series of these data determined very significant 11-yr, 22-yr and 44-yr variabilities that are possibly linked to coherent fluctuations in the high-speed solar wind precipitation into the atmosphere. The combined effect of such signals is found to explain 60% of the yearly rainfall variance.With 6 Figures     

雨量自动采集与Web图像制作技术

利用C^＋＋ Builder语言编写雨量计数软件,每计数一次数字信号即为0．1mm,同时存入数据库,实现对翻斗式遥测雨量器的雨量自动采集,并在Web中生成当日实时雨量的曲线图像,直观显示当天雨量、雨强等降水信息。该项技术现已在泉州气象网（www．qzqxw．com）上成功体现。     

雷达定量测量降水在佛子岭流域径流模拟中的应用

以位于合肥雷达西南100 km的佛子岭闭合流域 (1813 km2) 及该流域的6个子流域为研究区域, 用地面雨量计和雷达-雨量计联合校准两种方法进行流域面雨量计算, 将两种方法计算的面雨量分别作为TOPMODEL (TOPography based hydrological MODEL) 降水-径流模型的输入, 对模型输出结果进行比较。个例分析表明:雷达-雨量计联合测量降水的精度是否高于单独用地面雨量计计算的精度, 在一定程度上取决于用于校准的地面雨量计数目和代表性; 即使雨量计计算的整个流域面雨量与雷达-雨量计联合校准后的结果接近, 对应子流域面雨量的结果仍然会存在差别; 不同方法计算的某一子流域面雨量的差别越大, 则TOPMODEL水文模型输出的该子流域径流深的差别也越大。     

Squall lines and rainfall over Western Africa during summer 1986 and 87

Summary Using digitized IR images from the European satellite Meteosat, 153 squall lines (SLs) were observed over Western Africa during July, August and September 1986 and 87. The SL mean rainfall volume was computed using the daily rainfall amounts of more than 800 raingauges: 15 km³ in 1986 and 22.5 km³ in 1987. A mean amount of 15 mm was collected per rainy episode at a given station, however, as only about half of the stations situated under a SL experienced a rainy episode, the rainfall amount averaged along the total SL’s swath was 6.8 mm. With the help of the 8 daily Meteosat slots the SL’s area daily variation could be estimated: namely a minimum around noon and a maximum around midnight. Using the SLs displacements (east–west) one had access to the daily variation of the rainfall volume, a minimum in the morning and a maximum toward the end of the afternoon, as already found by several authors who used Meteosat images.     

Design storm prediction and hydrologic modeling using a web-GIS approach on a free-software platform

The aim of this work has been to implement a set of procedures useful to automatise the evaluation, the design storm prediction and the flood discharge associated with a selected risk level. For this purpose a Geographic Information System has been implemented using Grass 5.0.One of the main topics of such a system is a georeferenced database of the highest intensity rainfalls and their assigned duration recorded in Sicily. This database contains the main characteristics for more than 250 raingauges, as well as the values of intense rainfall events recorded by these raingauges. These data are managed through the combined use of the PostgreSQL and GRASS-GIS 5.0 databases. Some of the best-known probability distributions have been implemented within the Geographical Information System in order to determine the point and/or areal rain values once duration and return period have been defined. The system also includes a hydrological module necessary to compute the probable flow, for a selected risk level, at points chosen by the user.A peculiarity of the system is the possibility to querying the model using a web-interface. The assumption is that the rising needs of geographic information, and dealing with the rising importance of peoples participation in the decision process, requires new forms for the diffusion of territorial data. Furthermore, technicians as well as public administrators needs to get customized and specialist data to support planning, particularly in emergencies. In this perspective a Web-interface has been developed for the hydrologic system. The aim is to allow remote users to access a centralized database and processing-power to serve the needs of knowledge without complex hardware/software infrastructures.     

Experimental results on rainfall estimation in complex terrain with a mobile X-band polarimetric weather radar

In this work the capability of reliable rainfall measurements with small weather radars in complex terrain for flood forecasting purposes is examined. Rain measurements were carried out during winter–spring 2007 with a mobile X-band dual-polarization radar in the northwestern mountainous part of the island of Crete in Greece. In this area a 2D-video disdrometer and a network of raingauges was installed for radar calibration and evaluation of rainfall measurements, respectively. The complex terrain of the experimental site may significantly reduce the performance of rain measurements due to ground clutter and partial or total beam blockage. A beam blockage algorithm using high resolution terrain data was applied in order to find areas with significant terrain effects and estimate correction of the radar measurements. Rain attenuation correction was based on modern sophisticated algorithms using differential phase measurements. The accuracy of rainfall estimation from standard or polarimetric algorithms at plan position indicator (PPI) scans was examined for high-temporal resolution (1 min) rainfall rates and accumulated rainfall values for winter and spring time rain events. For high elevation measurements, which were required in order to avoid terrain effects in large areas of interest, a correction for the vertical-profile-of-reflectivity (VPR) was also applied to the radar data. An average VPR model used in the corresponding correction of reflectivity was constructed based on range–height indicator (RHI) scans. It was concluded that quantitative high resolution X-band radar observations of rainfall in complex terrain is possible after careful application of all the above processing steps.