共查询到20条相似文献，搜索用时 15 毫秒
1.
中国降水测量误差的研究 总被引：19，自引：0，他引：19
20世纪 ,国际上许多国家对降水测量进行了对比试验工作 ,以研究降水测量中的误差大小与分布。由于各个国家降水测量仪器的型式、尺寸以及安装高度不同 ,试验对比的降水测量误差的大小也就不同。为了弄清中国降水测量误差的大小 ,中国气象局选择了 30个基准基本站 ,建立标准雨量站网进行试验对比。本文介绍了中国标准雨量站网的设置以及对比资料的获取情况 ,对比分析了中国降水测量的随机误差、沾湿与蒸发误差、风场变形误差。经 30个标准雨量站 7a 2 90 0 0多次的 1台坑式雨量器、2台台站雨量器的对比观测 ,给出了中国降水量测量误差的大小、降水测量中的随机误差与系统误差的分布情况。经分析 ,对于收集口口径为 2 0cm ,安装高度为 70cm的台站普通雨量器 ,每次测量随机误差累计平均值为 0 .0mm ,沾湿误差为 0 .2mm ,蒸发误差为 0 .0mm ,降雨风场变形误差为 0 .19mm ,降雪为 0 .32mm。降雨测量的平均相对误差约为 4 .34%～ 15 .2 8% ,降雪测量的平均相对误差约为 6 .17%～ 39.99%。 相似文献
2.
3.
In this paper, a modern techniqne for correction of precipitation measured with a Nipher shielded rain gauge, with the use of the Valdai Control System as an intercomparison reference, is presented. This technique allows obtaining unbiased daily and timed precipitation data not affected by the rain gauge systematic errors. In conjunction with the existing method of the bias correction for precipitation measured with the Tretyakov precipitation gauge, the problem of generation of unbiased precipitation time series, which includes both types of measurements, covers the entire period of measurements, and has any (i.e., daily through yearly) temporal resolution, is solved. The results of correction for nine stations located in different climatic zones of the Russian Federation are shown. The results are summarized and presented in the form of long-term averages. Statistically homogeneous precipitation time series for the period from 1936 to 2000 are obtained. Temporal trends of annual and cold-season precipitation are calculated and analysed, and their statistical significance is estimated. 相似文献
4.
为了更好地使用降水观测数据,对引起称重观测和人工观测的差异原因进行分析,选取北京市15个国家级地面观测站2012年11月—2014年1月称重式降水传感器与人工观测降水量业务资料,探讨称重观测与人工观测累积降水量的差异,并细化为对固态降水和液态降水两种降水类型进行相关性研究。结果表明:称重观测与人工观测日降水量相关系数为0.9990, 88.0%的对比次数中, 两者日降水量差值满足业务要求;在出现固态降水时,称重观测较人工观测降水量偏大,在出现液态降水时,称重观测较人工观测降水量偏小;两者在日降水量等级判断差异较小,小量降水时称重观测的能力较优;防风圈可显著提高称重观测固态降水的捕捉率,而称重观测内筒蒸发对夏季降水测量有一定影响。 相似文献
5.
Liquid precipitation amounts below 0.05 mm in combination with intervals of measurement greater than 3 min and temperature above 15 °C can considerably affect the measured precipitation using electronic weighing gauges. This was shown by tests using different weights put in the gauge in different intervals in order to simulate different precipitation amounts and measuring intervals. These results were confirmed by field intercomparison measurements using pit gauges in two locations in Slovakia. In total, 1571 weight tests consisting of combinations of simulated precipitation amounts of 0.025, 0.05, 0.2 mm and measuring intervals of 1, 2, 3, 5 and 10 min were carried out. Based on these tests and special software, a new gauge was developed. Using this gauge, the abovementioned error sources were minimized. The Slovak Hydrometeorological Institute now uses it at 90 gauge sites. This type of gauge was selected to participate in the current World Meteorological Organization, WMO, Intercomparison measurements of recording precipitation gauges. 相似文献
6.
The WMO recommendations on solid precipitation correction, based on generalized results of precipitation gauge intercomparisons performed in 1985–1996, do not take into account systematic errors in precipitation measurements such as wind-induced at high winds and false precipitation blown by wind into the precipitation gauge during strong blizzards at low temperatures, typical of high latitudes. To eliminate these biases in solid precipitation measurements in the Arctic latitudes, special procedures are proposed for three different national methods of precipitation measurement in Russia, the United States (Alaska), and Canada. Differences in the correction methods in these countries are caused by differences in the design of instruments, observation technique, climate, and content of data archives for calculating the measurement errors. Results of application of the proposed procedures for precipitation correction in the Arctic regions of the above-mentioned countries are discussed. The results are compared against the maps of corrected precipitation in the world water budget and snow, ice resources atlases and in the Handbook for Climate of the USSR. 相似文献
7.
8.
The errors in radar quantitative precipitation estimations consist not only of systematic biases caused by random noises but also spatially nonuniform biases in radar rainfall at individual rain-gauge stations.In this study,a real-time adjustment to the radar reflectivity-rainfall rates(Z-R) relationship scheme and the gauge-corrected,radar-based,estimation scheme with inverse distance weighting interpolation was developed.Based on the characteristics of the two schemes,the two-step correction technique of radar quantitative precipitation estimation is proposed.To minimize the errors between radar quantitative precipitation estimations and rain gauge observations,a real-time adjustment to the Z-R relationship scheme is used to remove systematic bias on the time-domain.The gauge-corrected,radar-based,estimation scheme is then used to eliminate non-uniform errors in space.Based on radar data and rain gauge observations near the Huaihe River,the two-step correction technique was evaluated using two heavy-precipitation events.The results show that the proposed scheme improved not only in the underestimation of rainfall but also reduced the root-mean-square error and the mean relative error of radar-rain gauge pairs. 相似文献
9.
湖南省97个国家气象站自2017年开始陆续安装了雨滴谱仪,2018年1月1日起进行平行观测。为分析评估其探测降水量的准确性,选取湖南省12个国家站2018年雨滴谱仪观测资料和自动站翻斗雨量计小时降水资料,从总体观测误差、不同降水量级下观测误差和累积降水量观测误差3个方面进行对比分析,结果表明：（1）雨滴谱仪小时降水量和翻斗雨量计小时降水量存在显著的相关性,R2平均为0.94,其中南岳站R2最低为0.90,浏阳站R2最高为0.98,12个站的小时降水量绝对偏差均值为0.34mm;（2）当小时降水量Rh<1.0mm时,各站雨滴谱仪降水量较翻斗雨量计降水量平均偏大0.05mm,且平均差值绝对值均在0.2mm以下;当1.0mm≤Rh<2.6mm时,大部分站点雨滴谱降水量均大于或与翻斗雨量计降水量相当;当2.6mm≤Rh<5.0mm时,株洲和南岳站雨滴谱降水量较翻斗雨量计降水量明显偏小,武冈和娄底站雨滴谱仪降水量则明显偏高;当5.0mm≤Rh<8.0mm时,除株洲和南岳站外,其它各站雨滴谱降水量均大于或与翻斗雨量计降水量相当;当8.0mm≤Rh<16.0mm 时,除株洲和南岳站雨滴谱仪降水量偏小外,其他各站雨滴谱仪降水量均较翻斗雨量计降水量偏大;当Rh≥16.0mm时,雨滴谱仪降水量偏差明显变大,平均偏差绝对值达到3.570mm;（3）雨滴谱仪累计降水量和翻斗雨量计累计降水量变化趋势基本一致,除汨罗和南岳站外,雨滴谱仪累计降水量常表现为偏多。通过分析可见,湖南省雨滴谱仪雨量观测有较好可靠性,可为强降水监测预警、人工影响天气及降水数据订正等提供数据支撑。 相似文献
10.
中国区域高分辨率多源降水观测产品的融合方法试验 总被引：5，自引：0，他引：5
高质量、高分辨率降水产品研制对于数值天气模式检验、水文陆面模拟、山洪地质灾害监测有着重要意义。利用中国近4万自动气象站逐时降水资料、中国雷达定量降水估计和CMORPH卫星反演降水产品,开展0.05°×0.05°和0.01°×0.01°两种高分辨率下的三源降水融合方法研究试验,探讨如何有效引入雷达高分辨率信息来提高降水产品质量。一方面,在0.05°分辨率上,先以自动气象站观测降水数据为基准,采用概率密度函数（PDF）匹配法订正雷达和卫星估测降水产品的系统偏差,将雷达降水产品的偏差从-0.05 mm/h降至-0.008 mm/h;再采用贝叶斯模型平均（BMA）方法融合雷达和卫星降水产品,形成0.05°分辨率的中国区域覆盖完整且最优的联合降水背景场。此外,在0.01°分辨率上,以0.05°分辨率的卫星-雷达贝叶斯模型平均联合降水产品为背景,采用1 km雷达估测降水的空间结构信息进行降尺度,亦能有效提高0.01°分辨率背景场的质量。然后,分别以不同分辨率的卫星-雷达联合降水产品为背景,采用统计方法量化误差估计,再采用最优插值方法融入地面观测。通过2419个中国国家级气象台站的独立样本检验,评估了多种类型的降水资料及融合试验产品在中国地区的质量。结果表明,两种分辨率的三源融合试验产品的精度均优于任何单一来源的降水产品,特别是在站点稀疏地区,降水精度均较融合前有显著提高,达到了较好的融合效果,其中在0.05°分辨率上采用“概率密度函数+贝叶斯模型平均+最优插值”方法的三源融合降水产品整体质量最好,而0.01°分辨率上基于“概率密度函数+贝叶斯模型平均+降尺度+最优插值”方法的三源融合降水产品在强降水监测上更有优势。 相似文献
11.
基于贝叶斯融合方法的高分辨率地面-卫星-雷达三源降水融合试验 总被引：15，自引：1，他引：14
为了探讨一种适用于区域性的地面、雷达、卫星等多源降水资料融合的方法,一种曾用于高分辨雷达、卫星土壤湿度产品反演的贝叶斯融合(Bayesian Merging)方法被尝试应用于江淮地区1 h-0.05°×0.05°经纬度高分辨率的雷达估测降水、卫星反演降水与地面站点观测降水3种资料的融合。在应用该方法时,通过2009年8月样本统计分别估计卫星和雷达反演降水的误差关系,通过曲线拟合建立误差方程,并以卫星资料作为背景场,但在融合时将雷达估测降水作为新的观测信息与地面观测降水同时引入。融合试验检验结果表明:贝叶斯融合方法能够有效实现雷达、地面、卫星3种不同来源资料的融合,该方法生成的多源融合产品的精度均优于任何单一来源的降水产品。 相似文献
12.
为考察概率密度匹配法 (PDF方法) 对中国区域卫星反演降水产品系统误差订正的适用性,基于逐日和逐时我国地面观测降水量资料,引入PDF方法,分别对逐日0.25°×0.25°水平分辨率和逐时0.1°×0.1°水平分辨率的CMORPH (Climate Prediction Center Morphing Technique) 卫星降水产品的系统误差进行订正。在分析CMORPH卫星降水产品误差特征的基础上,根据两种资料不同的时空分辨率和误差特点,调整概率密度匹配时选取样本的时间和空间范围,设计相应的订正方案。评估结果表明: PDF方法订正后, 两种分辨率卫星降水资料在中国区域系统误差均显著减小,达到了理想的订正效果。在我国站点稀疏的西部地区,订正后的CMORPH卫星降水产品仍保持卫星观测的降水空间分布,降水量也明显接近于地面观测降水量。可见,PDF方法是中国区域卫星反演降水产品系统误差订正的一种有效方法。 相似文献
13.
Machine learning models were used to improve the accuracy of China Meteorological Administration Multisource Precipitation Analysis System (CMPAS) in complex terrain areas by combining rain gauge precipitation with topographic factors like altitude, slope, slope direction, slope variability, surface roughness, and meteorological factors like temperature and wind speed. The results of the correction demonstrated that the ensemble learning method has a considerably corrective effect and the three methods (Random Forest, AdaBoost, and Bagging) adopted in the study had similar results. The mean bias between CMPAS and 85% of automatic weather stations has dropped by more than 30%. The plateau region displays the largest accuracy increase, the winter season shows the greatest error reduction, and decreasing precipitation improves the correction outcome. Additionally, the heavy precipitation process’precision has improved to some degree. For individual stations, the revised CMPAS error fluctuation range is significantly reduced. 相似文献
14.
A pattern projection downscaling method is employed to predict monthly station precipitation. The predictand is the monthly precipitation at 1 station in China, 60 stations in Korea, and 8 stations in Thailand. The predictors are multiple variables from the output of operational dynamical models. The hindcast datasets span a period of 21 yr from 1983 to 2003. A downscaled prediction is made for each model separately within a leave-one-out cross-validation framework. The pattern projection method uses a moving window, which scans globally, in order to seek the most optimal predictor for each station. The final forecast is the average of the model downscaled precipitation forecasts using the best predictors and is referred to as DMME. It is found that DMME significantly improves the prediction skill by correcting the erroneous signs of the rainfall anomalies in coarse resolution predictions of general circulation models. The correlation coefficient between the prediction of DMME and the observation in Beijing of China reaches 0.71; the skill is improved to 0.75 for Korea and 0.61 for Thailand. The improvement of the prediction skills for the first two cases is attributed to three steps: coupled pattern selection, optimal predictor selection, and multi-model downscaled precipitation ensemble. For Thailand, we use the single-predictor prediction, which results in a lower prediction skill than the other two cases. This study indicates that the large-scale circulation variables, which are predicted by the current operational dynamical models, if selected well, can be used to make skillful predictions of local precipitation by means of appropriate statistical downscaling. 相似文献
15.
16.
17.
针对我国华南前汛期（4—6月）降水,基于国家气候中心第2代月动力延伸模式（DERF2.0）结果,利用非参数百分位映射方法将模式预测结果转化为概率预报,并进行概率订正。分别选用交叉建模与独立样本建模两种订正方法,并利用偏差、偏差百分率、时间相关系数、均方根误差等统计方法检验订正效果。结果表明:订正方法对预报技巧的改善与起报时间无显著相关,且具有误差稳定性,其订正效果受预报误差影响较小;与订正前模式预测降水落区的范围和平均强度相比,订正后结果与观测更接近;按百分位区间统计的不同强度降水订正预报均有明显改进;预测时段的订正效果与回报时段的订正效果基本一致。 相似文献
18.
最优多因子动态配置的东北汛期降水相似动力预报试验 总被引：4，自引：0，他引：4
基于中国气象局国家气候中心季节预报业务模式27a(1983—2009年)预报结果和同期美国气候预报中心组合降水分析(CMAP)资料及国家气候中心气候系统诊断预报室74项环流指数和NOAA40个气候指数(1951—2009年),提出了客观定量化的最优多因子动态配置汛期降水相似-动力预测新技术,并对中国东北地区汛期降水进行了预报试验。利用历史资料有用信息估算模式预报误差原理,选取4个历史相似年对应模式误差来估算当前模式预报误差。通过单因子交叉检验距平相关系数确定主导因子及演化相似因子,结合当前及前期优化多因子组合配置确定预报因子集,最后利用历史相似年对应模式误差来估算当前模式预报误差并订正国家气候中心季节预报业务模式的预报结果,得到预报的汛期降水。对2005—2009年进行独立样本检验的结果表明,此技术对中国东北地区汛期降水有一定预报技巧。证实了利用历史资料估计业务模式预报误差的另类途径是可行的,显示了在业务预报应用中的潜在能力。 相似文献
19.
利用1998-2013年TRMM月降水量产品与新疆同期的105个气象站地面观测降水量,运用逐步回归与BP神经网络方法,选取1998-2010年数据建立新疆地区的降水订正模型,并利用2011-2013年月降水量进行检验。结果表明:加入地形因子对TRMM月降水量产品订正效果明显,整体上两种模型对TRMM月降水量产品订正的相关系数从最初的0.66分别提高到0.75和0.80,相对误差由10.75%分别降低为4.88%和3.19%;月尺度上,TRMM月降水量产品相对误差为-5.68%~54.44%,经逐步回归模型订正后为-4.26%~32.57%,而BP神经网络模型订正后为-5.33%~24.48%,表明BP神经网络模型订正效果更好;从综合时间技巧评分ST看,订正后TRMM月降水量产品在各月的效果均有不同程度提高,逐步回归模型订正后提高0.01~0.49,BP神经网络模型订正后提高0.03~0.70。因此,基于逐步回归模型与BP神经网络模型订正的TRMM降水量产品均能够准确、定量地再现降水分布,为TRMM降水量产品质量改进提供一种较实用的参考方法。 相似文献
20.
大气降水中离子成分的电导率具有可加和性, 国际上已经普遍应用该原理对大气降水离子成分观测的数据质量进行分析和评估, 即所谓的相对电导率差 (conductance percent difference, CPD) 方法。该文应用CPD方法对我国4个大气本底观测站的电导率和降水离子成分数据进行了数据质量分析, 针对我国的降水电导率范围偏高等特点, 对国外推荐的CP D统计检验指标的适用性进行了讨论, 指出在我国应用CPD方法时宜采取pH值分组的方式, 并根据这种分组方式的统计分析, 估计4个大气本底观测站的部分pH值观测数据可能存在-0.05左右的测量误差。该文还依据降水中离子成分电导率的可加和性原理, 提出K-pH不等式方法, 可以用于中国气象局酸雨观测站网的pH值和电导率数据的现场校验和数据质量的分析评估。应用K-pH不等式方法对观测数据进行现场质量检验时, 对pH值小于5.0范围的酸性降水效果尤其显著。应用K-pH不等式方法对1992—2005年间全国酸雨观测站观测数据的统计分析显示, 部分酸雨观测站的pH值测量数据可能存在-0.1~-0.3左右的系统性负偏差。 相似文献