以用户为导向的交互式预报系统及应用研究

基于近年来涌现的有关新一代气象预报系统发展的认识,本文提出用户导向的交互式预报系统的概念模型。新系统强调在用户信息分析的基础上,发展从用户出发再回到用户不断自我改善的预报流程。系统组成的关键模块包括：用户端风险决策动态需求分析模块、物理预测模块、用户目标量的降尺度模块,用户端专业耦合模块及用户风险决策模块。文中阐述了系统中各模块间的联系、用户端信息在系统中的反馈作用以及具体的“交互式”方式。以临沂地区水文用户为例,以引发洪涝的降水事件为预报对象,利用TIGGE全球超集合预报,初步构建了一个临沂水文用户导向的可能致洪降水交互式预报系统。这个具备迭代式自我完善功能的新型预报系统包含了汛期随时变化的用户决策信息、由前期影响雨量和当前水文条件决定的可变致洪降水阈值以及一个动态的用户端预报水平和不确定性评估模块。初步结果表明,结合用户端信息的预报优于未考虑用户信息的预报结果,从而更直接地帮助用户进行防汛决策。个例研究也为发展更完整的用户导向预报系统提供了参考。     

Improving global rainfall forecasting with a weather type approach in Japan

An automated version of the weather type classification scheme was performed over Japan to characterize daily circulation conditions. A daily gridded field of mean sea-level pressure (MSLP) from the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis dataset (ERA-interim) and the THORPEX Interactive Grand Global Ensemble (TIGGE) daily forecast dataset were used. The weather type is advantageous as it provides an opportunity to improve global rainfall prediction by refining statistical bias correction. We distinguished 11 weather types: anticyclone, cyclone, hybrid and eight purely wind directions. The results indicate that the main weather types contributing to the total volume of rainfall are cyclone, hybrid, purely westerly and northwest winds. A gamma-based bias correction decreases the global rainfall forecast root mean square by 10%, while specific weather type gamma bias correction accounts for 5–10% root mean square error reduction, with a total decrease of errors up to a maximum of 20%. Both global and weather type bias corrections improve the extreme dependency scores (EDS), but for different extreme rainfall thresholds. The study advocates the use of weather type bias-correction methods for extreme event rainfall intensity corrections higher than 100 mm/d.

EDITOR

A. Castellarin

ASSOCIATE EDITOR

A. Jain     

基于TIGGE资料的西太平洋热带气旋多模式集成预报方法比较

基于TIGGE资料中CMA、ECMWF、JMA和NCEP四中心2010、2011和2012年3年的资料,采用集合平均（EMN）、加权集合平均（WEMN）、消除偏差集合平均（BREM）和加权消除偏差集合平均（即超级集合,SUP）四种方法,对西太平洋地区热带气旋路径与中心气压进行时效为24、48、72、96和120 h的多模式集成预报,评估了不同单中心预报结果,并分析了不同多模式集成预报方法的特点,对比了不同多模式集成方法的效果。结果表明,对于热带气旋路径和中心气压预报,各中心预报技巧不同,其中3年的CMA预报效果均较差,2010、2011年的ECMWF预报和2012年的NCEP预报效果最优;总体上几种多模式集成方法在120 h预报时效内均优于单模式预报,其中EMN作为一种最简单的集成预报方法,具有一定的局限性,而WEMN由于给不同单模式预报赋予了权重,因此相对于EMN能够得到更好的多模式集成预报结果;BREM方案由于消除了模式预报中的系统性偏差,因此集成预报效果也优于EMN;由于去除了模式预报偏差,同时给不同模式赋予了权重,SUP方案得到的集成预报效果最优。     

降水集合预报集成方法研究

基于TIGGE(the THORPEX Interactive Grand Global Ensemble)资料,对中国气象局(CMA)、欧洲中期天气预报中心(ECMWF)、美国国家环境预报中心(NCEP)和日本气象厅(JMA)的集合数值预报结果进行降水集成.采用算术平均法、TS评分集成法和BS评分集成法在我国东南地区进行降水集成,对比分析结果表明:基于TS评分的多模式降水集成无论在分区降水评分中,还是在东南地区的台风型降水和非台风型降水实例中,都有效地改进了大雨以上的降水预报效果;基于BS评分的集成方法和算数平均集成法预报效果次之.东南地区5个子区域的降水集成试验结果表明:各子区域基于TS评分集成后降水的平均绝对误差普遍小于基于BS评分后的降水平均绝对误差.广东东南和浙江北部区域基于TS集成后的降水TS评分值最优,浙闽沿海和广东西北部区域基于TS集成后的降水TS评分次之,处于中上水平.基于算术平均集成和BS集成的降水的TS评分值只有在广东东南区域表现出较好的效果.     

Early Flood Warning for Linyi Watershed by the GRAPES/XXT Model Using TIGGE Data

Early and effective flood warning is essential for reducing loss of life and economic damage.Three global ensemble weather prediction systems of the China Meteorological Administration (CMA),the Europe...     

Evaluation of TIGGE Ensemble Forecasts of Precipitation in Distinct Climate Regions in Iran

The application of numerical weather prediction(NWP) products is increasing dramatically. Existing reports indicate that ensemble predictions have better skill than deterministic forecasts. In this study, numerical ensemble precipitation forecasts in the TIGGE database were evaluated using deterministic, dichotomous(yes/no), and probabilistic techniques over Iran for the period 2008–16. Thirteen rain gauges spread over eight homogeneous precipitation regimes were selected for evaluation.The Inverse Distance Weighting and Kriging methods were adopted for interpolation of the prediction values, downscaled to the stations at lead times of one to three days. To enhance the forecast quality, NWP values were post-processed via Bayesian Model Averaging. The results showed that ECMWF had better scores than other products. However, products of all centers underestimated precipitation in high precipitation regions while overestimating precipitation in other regions. This points to a systematic bias in forecasts and demands application of bias correction techniques. Based on dichotomous evaluation,NCEP did better at most stations, although all centers overpredicted the number of precipitation events. Compared to those of ECMWF and NCEP, UKMO yielded higher scores in mountainous regions, but performed poorly at other selected stations.Furthermore, the evaluations showed that all centers had better skill in wet than in dry seasons. The quality of post-processed predictions was better than those of the raw predictions. In conclusion, the accuracy of the NWP predictions made by the selected centers could be classified as medium over Iran, while post-processing of predictions is recommended to improve the quality.     

TIGGE数据接收问题分析与解决

2010年1月欧洲中期天气预报中心（ECMWF）开始提供高分辨率产品,中国气象局TIGGE （THORPEX Interactive Grand Global Ensemble）数据接收完整性受到较大影响,数据丢失量大,针对此问题,对数据接收环节进行了逐一分析,发现数据共享软件（全球气象数据共享系统）使用的TCP传输协议在高带宽、高时延网络环境下存在性能瓶颈,制约了当前网络吞吐量的提高,不能满足每天大数据量的传输要求。通过对TIGGE系统的TCP接收窗口大小进行调整,提高了TCP协议性能和当前网络吞吐量。调整后,中国气象局数据接收情况与全球其他业务中心基本一致,实现了对全球各中心数据的完整接收。     

Antarctic Radiosonde Observations Reduce Uncertainties and Errors in Reanalyses and Forecasts over the Southern Ocean:An Extreme Cyclone Case

Cyclones with strong winds can make the Southern Ocean and the Antarctic a dangerous environment.Accurate weather forecasts are essential for safe shipping in the Southern Ocean and observational and logistical operations at Antarctic research stations.This study investigated the impact of additional radiosonde observations from Research Vessel"Shirase"over the Southern Ocean and Dome Fuji Station in Antarctica on reanalysis data and forecast experiments using an ensemble data assimilation system comprising the Atmospheric General Circulation Model for the Earth Simulator and the Local Ensemble Transform Kalman Filter Experimental Ensemble Reanalysis,version 2.A 63-member ensemble forecast experiment was conducted focusing on an unusually strong Antarctic cyclonic event.Reanalysis data with(observing system experiment)and without(control)additional radiosonde data were used as initial values.The observing system experiment correctly captured the central pressure of the cyclone,which led to the reliable prediction of the strong winds and moisture transport near the coast.Conversely,the control experiment predicted lower wind speeds because it failed to forecast the central pressure of the cyclone adequately.Differences were found in cyclone predictions of operational forecast systems with and without assimilation of radiosonde observations from Dome Fuji Station.     

THORPEX国际科学研究新进展

2009年9月14—18日,第三届THORPEX国际科学研讨会在美国加州蒙特利市顺利召开。大会就五个专题进行学术交流,分别是全球交互式预报系统,区域活动和交叉研究主题,可预报性和动力过程,资料同化和观测策略,社会和经济效益研究及应用。本文简要总结了参与此次研讨会的各区域、各工作组及与会专家的最新研究成果。从会议的报告来看,THORPEX的进展主要表现在改善高影响天气外场观测活动以及对如何设计全球观测系统的认识、面向TIGGE的集合预报技术的研究等。     

Development and Application of an Atmospheric-Hydrologic-Hydraulic Flood Forecasting Model Driven by TIGGE Ensemble Forecasts

A coupled atmospheric-hydrologic-hydraulic ensemble flood forecasting model,driven by The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) dat...