降水临近预报及其在水文预报中的应用研究进展          下载免费PDF全文

刘佳  邱庆泰  李传哲  焦裕飞  王维  于福亮 《水科学进展》2020,31(1):129-142

随着全球气候变化、自然变迁及陆表生境改变,极端天气频发且呈现出多尺度时空变异特征,对其进行预报和预警一直是气象水文领域关注的焦点。临近预报可较准确地预报未来短时间天气显著变化,是当前预报强降水等极端事件的主要手段。从基于天气雷达0~3 h外推临近预报、融合数值模式0~6 h临近预报的发展历程梳理了临近预报的研究进展,阐述了雷达外推算法的发展进程、雷达外推预报与数值模式预报融合技术进展,指出"取长补短"的0~6 h融合预报在提高降水预报精度、延长降水预见期等多方面有较大的发展潜力,进一步探寻及提升融合技术是未来融合预报发展的核心。将临近预报以气象水文耦合的方式引入水文预报是从源头提高水文预报精度、保障水文预报效果的主要途径,总结了现阶段主流耦合方式、空间尺度匹配技术、水文模型不确定等陆气耦合中的关键问题,阐述了外推临近预报、融合临近预报作为水文预报输入的研究进展,明确了融合临近预报在延长洪水预见期、提高洪水预报精度中存在优势,并讨论了未来的研究重点及发展方向。  相似文献   

Necessary and sufficient conditions for the existence of a solution to the one-dimensional magnetotelluric inverse problem     

E. Yee  K. V. Paulson 《Geophysical Journal International》1988,93(2):279-293

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Comparison of methods for applying the Priestley–Taylor equation at a regional scale     

F. Castellvi  C. O. Stockle  P. J. Perez  M. Ibaez 《水文研究》2001,15(9):1609-1620

The scenario assumed for this study was that of a region with a complete or first‐order weather station surrounded by a network of second‐order stations, where only monthly air temperature data were available. The objective was to evaluate procedures to estimate the monthly α parameter of the Priestley–Taylor equation in the second‐order stations by adjusting and extrapolating α values determined at the first‐order station. These procedures were applied in two climatic zones of north‐east Spain with semi‐arid continental and semi‐arid Mediterranean climates, respectively. Procedure A assumed α to be constant over each zone for each month (direct extrapolation). Procedure B accounted for differences in vapour pressure deficit and available energy for evapotranspiration between the first‐ and second‐order stations. Procedure C was based on equating the Penman–Monteith (P–M) and Priestley–Taylor (P–T) equations on a monthly basis to solve for α. Methods to estimate monthly mean vapour pressure deficit, net radiation and wind speed were developed and evaluated. A total of 11 automated first‐order weather stations with a minimum period of record of 6 years (ranging from 6 to 10 years) were used for this study. Six of these stations were located in the continental zone and five in the Mediterranean zone. One station in each zone was assumed to be first‐order whereas the remainder were taken as second‐order stations. Monthly α parameters were calibrated using P–M reference crop evapotranspiration (ET₀) values, calculated hourly and integrated for monthly periods, which were taken as ‘true’ values of ET₀. For the extrapolation of monthly α parameters, procedure A was found to perform slightly better than procedure B in the Mediterranean zone. The opposite was true in the continental zone. Procedure C had the worst performance owing to the non‐linearity of the P–M equation and errors in the estimation of monthly available energy, vapour pressure deficit and wind speed. Procedures A and B are simpler and performed better. Overall, monthly P–T ET₀ estimates using extrapolated α parameters and R_n?G values were in a reasonable agreement with P–M ET₀ calculated on an hourly basis and integrated for monthly periods. The methods presented for the spatial extrapolation of monthly available energy, vapour pressure deficit and wind speed from first‐ to second‐order stations could be useful for other applications. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Numerical integration for the real time production of fundamental ephemerides over a wide time span     

Aldo Vitagliano 《Celestial Mechanics and Dynamical Astronomy》1996,66(3):293-308

A simplified model of the solar system has been developed along with an integration method, enabling to compute planetary and lunar ephemerides to an accuracy better than 1 and 2 milliarcsecs, respectively. On current personal computers, the integration procedure (SOLEX) is fast enough that by using a relatively small ( 20 Kbytes/Cy) database of starting conditions, any epoch in the time interval (up to ±100 Cy) covered by the database can be reached by the integrator in a few seconds. This makes the algorithm convenient for the direct computation of high precision ephemerides over a time span of several millennia.  相似文献   

波阻抗映射法外推   总被引：4，自引：1，他引：3       下载免费PDF全文

林小竹  钱绍新 《地球物理学报》1998,41(1):109-116

首先介绍了自适应滤波的方法和波阻抗映射法外推的基本原理．在小反射系数的假设条件下推导了对数波阻抗和地震道之间近似为线性映射的关系,应用自适应滤波的方法可以实现这种映射．实际资料的试算结果表明,该方法能够提供分辨率明显高于常规方法的波阻抗或层速度剖面,并与测井资料较吻合．因此,它作为测井约束反演的补充手段,是一种可用于开发地震的新方法．最后讨论了映射法波阻抗反演的局限性．  相似文献   

Vapour source and spatiotemporal variation of precipitation isotopes in Southwest Spain     

Claus Kohfahl  Rolf Fonseca Rodríguez  Fernando Ruiz Bermudo  Iñaki Vadillo 《水文研究》2021,35(12):e14445

The δ²H and δ¹⁸O composition of 77 precipitation samples collected between January 2014 and April 2019 from two sites across the Guadalquivir Basin, SW Spain, were analysed. The first site is located in an urban area of Seville at 100 km distance to the Atlantic coast and the second site is located in a dune area of the Doñana National Park a few kilometres from the coast. Sampling was performed within intervals of at least 14 days if rain occurred but frequently intervals were longer according to the rainfall incidence. Samples from both sites are available for the period February 2016 to June 2018 with six samples containing identical rain events at both locations. Precipitation weighted averages and local meteoric water lines produced by weighting and non-weighting regression methods are presented for its use in hydrological applications. Results show a remarkably high variability in δ²H and δ¹⁸O values and precipitation weighted average d-excess values of 11.8‰ and 13‰ at the sites Plaza de España and Doñana, respectively. Temperature and amount effects were found to be weak. A significant influence of secondary evaporation for single rainfall events during summer was identified by enriched isotopic signatures with reduced d-excess values plotting close or below the global meteoric water line. Backward trajectory analysis of 115 days with daily rainfall above 3 mm yield a predominant Atlantic Ocean vapour source with negligible Mediterranean influence and therefore, d-excess variability is attributed to the different ocean surface conditions of relative humidity and sea surface temperature. Parallel sampling indicate very similar isotopic signatures at both sites and point to the existence of thermal effects of the Plaza de España site in Seville city during the summer season.  相似文献   

Application of Multi-Scale Tracking Radar Echoes Scheme in Quantitative Precipitation Nowcasting     

WANG Gaili  WONG Waikin  LIU Liping  WANG Hongyan 《大气科学进展》2013,30(2):448-460

A new radar echo tracking algorithm known as multi-scale tracking radar echoes by cross-correlation(MTREC) was developed in this study to analyze movements of radar echoes at different spatial scales.Movement of radar echoes,particularly associated with convective storms,exhibits different characteristics at various spatial scales as a result of complex interactions among meteorological systems leading to the formation of convective storms.For the null echo region,the usual correlation technique produces zero or a very small magnitude of motion vectors.To mitigate these constraints,MTREC uses the tracking radar echoes by correlation(TREC) technique with a large "box" to determine the systematic movement driven by steering wind,and MTREC applies the TREC technique with a small "box" to estimate small-scale internal motion vectors.Eventually,the MTREC vectors are obtained by synthesizing the systematic motion and the small-scale internal motion.Performance of the MTREC technique was compared with TREC technique using case studies:the Khanun typhoon on 11 September 2005 observed by Wenzhou radar and a squall-line system on 23 June 2011 detected by Beijing radar.The results demonstrate that more spatially smoothed and continuous vector fields can be generated by the MTREC technique,which leads to improvements in tracking the entire radar reflectivity pattern.The new multi-scale tracking scheme was applied to study its impact on the performance of quantitative precipitation nowcasting.The location and intensity of heavy precipitation at a 1-h lead time was more consistent with quantitative precipitation estimates using radar and rain gauges.  相似文献   

COTREC方法在江西地区的应用和检验          下载免费PDF全文

邹海波  章毅之  解震华  李蕾 《气象与减灾研究》2019,42(2):105-112

基于江西及其周边地区的雷达组合反射率拼图,将二维Boussinesq(水平无辐散)质量连续方程约束至江西地区的TREC风场,得到改善后的TREC风场(COTREC风场),并基于COTREC风矢量开展了江西地区雷达回波的外推。个例分析表明,经过二维无辐散连续方程约束后,COTREC风中的噪声和不一致得到了显著的平滑,其风速水平梯度和风向切变都显著减小。基于COTREC风外推的雷达回波在形态上也得到了明显的改善,其外推回波中由风场的噪声或不一致引起的异常失真回波明显减少。为了进一步评估TREC和COTREC方法的外推表现,对2018年7月1—31日江西地区有明显降水的287个时次的雷达回波分别进行了1 h和2 h外推。结果表明:相对于TREC方法,COTREC方法在1 h和2 h的外推时间上均能改善外推回波的精度,其外推回波与实况的相关系数和TS评分均较TREC方法高。  相似文献   

基于江西省雷达回波拼图的TREC方法应用及效果检验          下载免费PDF全文

易雪婷  傅文兵  邹海波  贺志明  李蕾 《气象与减灾研究》2019,42(1):16-23

基于江西省及周边16部新一代多普勒天气雷达拼图资料,利用交叉相关跟踪法(TREC)计算江西地区雷达回波的移动矢量(TREC风),并对求解的TREC风进行异常值更正和空洞补齐等质量控制,最后利用后向外推法对江西地区2017年6月29日09:54的雷达回波进行2 h内的外推。结果表明,TREC方法能较好地获得江西地区未来2 h内的雷达回波位置和空间结构,且在0—1 h的外推回波非常接近实况。通过对2018年6月1—9日201个天气过程0—2 h外推的TS评分统计表明,基于该方法外推的2 h内的雷达回波精度都较高(TS评分0.3),但TS评分随外推时间的增长而快速降低,当外推时间为30 min时TS评分高达0.61,外推时间增至60 min时TS评分降至0.48,外推时间延长至120 min时TS评分进一步减至0.31。  相似文献   

基于PSCF与CWT方法的赣江新区大气污染物潜在源区个例分析          下载免费PDF全文

蒋子瑶  彭王敏子  陈琦 《气象与减灾研究》2022,45(3):216-224

利用TrajStat软件和GDAS全球同化气象数据,对江西省赣江新区2011—2020年四季72 h气团后向轨迹进行聚类分析,并结合PM2.5和O3逐小时浓度数据,运用潜在源贡献因子分析法（PSCF）和浓度权重轨迹分析法（CWT）分析了2016年12月2—10日一次污染天气过程中大气污染物输送对赣江新区上空污染物浓度的贡献。结果表明,赣江新区2011—2020年四季气团后向轨迹中占比最大的均为短支气流,其中春季的短支气流来源于东侧,其他季节均来源于东北方向的安徽省,夏季和冬季的长支气流与季风的季节性变化一致。在2016年12月2—10日的污染天气过程中,赣江新区的PM2.5潜在源区主要分布于江西省北部、湖北省东南部,O3潜在源区主要分布于江西省北部、湖北省南部和湖南省东北小部分地区;同时天气形势显示,赣江新区处在槽后脊前,湖北省东南部存在偏强西北风,为大气污染物向赣江新区的输送创造了条件。  相似文献