集合预报的现状和前景

综合论述了近年来已在国际上引起高度重视的新一代动力随机预报方法 ——— 集合预报。 随着计算机技术的迅猛发展和由于大气初值和数值模式中物理过程存在着不确定性的事实, 这一方法无疑代表了数值天气预报未来演变发展的方向。 未来的天气预报产品预计将从“决定论”的预报转变为“随机论”的预报来正确地表达气象科学中这一所谓“可预报性问题”, 以便更好地为用户服务。 文中扼要地叙述了集合预报的概念、基本问题及其最新的研究动态和发展, 包括(1)如何建立和评估一个集合预报系统;(2)如何正确地表征大气初值和模式物理过程的不确定性与随机性;(3)如何从集合预报中提炼有用的预报信息和合理地解释、检验集合预报的产品, 特别是概率预报。 除了直接在天气预报上的应用, 还提到集合预报在气象观测和资料同化方面应用的动态, 以引起有关研究人员的注意。     

Operative Scheme for the Short-range Complex Forecasting of Surface Air Temperature and Humidity

The statistical scheme is proposed for the forecast of surface air temperature and humidity using operative weather forecasts with 3–5-day lead time from the best forecasting hydrodynamic models as well as the archives of forecasts of these models and observational data from 2800 weather stations of Russia, Eastern Europe, and Central Asia. The output of the scheme includes the forecasts of air temperature for the standard observation moments with the period of 6 hours and extreme temperatures with the lead times of 12–120 hours. The accuracy of temperature and humidity forecasts for the period from July 2014 till June 2017 is much higher than that for the forecasts of original hydrodynamic models. The skill scores for extreme temperature forecasts based on the proposed method are compared with the similar results of the Weather Element Computation (WEC) forecasting scheme and forecasts by weathermen.     

Errors in forecasting social phenomena

In this paper, we examine the nature of forecasting errors associated with social phenomena. We introduce the notion of predictive likelihood and conclude a) that there is a need to separate the problem of parametric estimation and inference from the problem of forecasting, b) that all forecasts linked to decisions require at least an implicit structural model, c) that conventional cost functions have adversely affected the quality of social science forecasts, and d) that there is a need to develop forecasting procedures robust to different kinds of cost functions.     

Forecasting health status changes in an aging U.S. population: Assessment of the current status and some proposals

Much interest has been recently focused on forecasting population health changes such as population aging and life expectancy increases at advanced ages, qualitative changes in health and survival, changes in federal reimbursement systems, and the need to forecast for long-range capital investment in specialized health facilities. Recent efforts at forecasting health and morbidity changes in the population are reviewed in this paper and the recent lack of methodological innovation in health forecasting strategies is examined. Two forecasting models—stochastic compartmental systems and mixed multivariate continuous state—discrete state processes—are described. We show how these models can be applied to health forecasting using existing data, how they can be used in a complementary fashion to improve health projections made from any one type of data, and how the mixed multivariate stochastic process model can be used to evaluate assumptions made in the compartment modeling approach.     

美国天气预报的效果与预报估价

本文介绍美国天气预报的效果与对预报的估价。根据检验美国国家天气局从1967年到1985年逐日天气预报的效果表明，目前的预报水平明显高于15到20年前的预报水平。特别是客观预报效果明显的提高是值得引起注意的。预报的估价是一个很复杂的问题。本文主要介绍了美国的气象预报正确与否的得失估价及给经济带来获益或损失的经济评价工作。     

A study of effectiveness of the ensemble long-term forecasts of spring floods issued with physically based models of the river runoff formation

In this paper, possible ways to increase effectiveness of the long-term ensemble spring floods forecasting and to assess their uncertainty based on the physical-mathematical model of the runoff formation (for the Vyatka River case study) are studied. It is shown that deterministic forecasts issued by using this approach are more accurate than those obtained from the traditional forecasting methods based on regression relationships. Probabilistic methods of forecasting of the spring flood volume and maximum discharge, which are issued by using various ways of the weather ensembles setting, are compared. Reliability of probabilistic forecasts of the volume and maximum discharge is estimated.     

Operative Scheme for the Short-range Complex Forecasting of Wind

We describe our scheme of the operative wind (and possible gusts) forecasts with the lead time up to 3 days and evaluate its success. It uses joint statistical processing of the results of several best operative forecasting hydrodynamic weather forecasting schemes. This approach allowed us to reduce the error with respect to original schemes. The operative forecast and its evaluation for the period of 2014–2016 is implemented for ~ 2800 cities of Russia, Belarus, and Central Asia. The update results are represented at the official site of the Hydrometeorological Center of Russia every day at 8:30 (a.m. and p.m.), Moscow time.     

Multischeme ensemble forecasting of surface temperature using neural network over Turkey

The ensemble method has long been used to reduce the errors that are caused by initial conditions and/or parameterizations of models in forecasting problems. In this study, neural network (NN) simulations are applied to ensemble weather forecasting. Temperature forecasts averaged over 2 weeks from four different forecasts are used to develop the NN model. Additionally, an ensemble mean of bias-corrected data is used as the control experiment. Overall, ensemble forecasts weighted by NN with feed forward backpropagation algorithm gave better root mean square error, mean absolute error, and same sign percent skills compared to those of the control experiment in most stations and produced more accurate weather forecasts.     

The Meta-Gaussian Bayesian Processor of Forecasts and Associated Preliminary Experiments

Public weather services are trending toward providing users with probabilistic weather forecasts, in place of traditional deterministic forecasts. Probabilistic forecasting techniques are continually being improved to optimize available forecasting information. The Bayesian Processor of Forecast (BPF), a new statistical method for probabilistic forecast, can transform a deterministic forecast into a probabilistic forecast according to the historical statistical relationship between observations and forecasts generated by that forecasting system. This technique accounts for the typical forecasting performance of a deterministic forecasting system in quantifying the forecast uncertainty. The meta-Gaussian likelihood model is suitable for a variety of stochastic dependence structures with monotone likelihood ratios. The meta-Gaussian BPF adopting this kind of likelihood model can therefore be applied across many fields, including meteorology and hydrology. The Bayes theorem with two continuous random variables and the normal-linear BPF are briefly introduced. The meta-Gaussian BPF for a continuous predictand using a single predictor is then presented and discussed. The performance of the meta-Gaussian BPF is tested in a preliminary experiment. Control forecasts of daily surface temperature at 0000 UTC at Changsha and Wuhan stations are used as the deterministic forecast data. These control forecasts are taken from ensemble predictions with a 96-h lead time generated by the National Meteorological Center of the China Meteorological Administration, the European Centre for Medium-Range Weather Forecasts, and the US National Centers for Environmental Prediction during January 2008. The results of the experiment show that the meta-Gaussian BPF can transform a deterministic control forecast of surface temperature from any one of the three ensemble predictions into a useful probabilistic forecast of surface temperature. These probabilistic forecasts quantify the uncertainty of the control forecast; accordingly, the performance of the probabilistic forecasts differs based on the source of the underlying deterministic control forecasts.     

GRAPES全球模式的误差评估和订正

以欧洲中期预报中心的ERA-interim再分析资料为参考,对GRAPES全球模式的数值预报结果误差进行了评估,并运用基于历史资料的模式距平积分订正（ANO）方法,对数值预报结果进行了订正试验,检验了ANO方法对GRAPES模式全球中期天气预报的订正改进效果。对1984~2014逐年7月15~24日10天的预报结果订正前后对比分析表明,ANO方法对不同区域位势高度、温度等要素预报订正效果明显,31个个例200 hPa位势高度一周预报距平相关系数平均提高0.05、均方根误差减少12 gpm。其它各层误差订正也显示类似结果,验证了ANO方法对提高GRAPES全球模式10天数值天气预报技巧的有效性,并与MOS（Model Output Statistics）方法对比,更便利、更经济,具有更好的可操作性以及业务预报应用能力。     

Forecasting in the social and natural sciences: An overview and analysis of isomorphisms

This article identifies and analyzes several points of similarity in the structure and context of forecasting in the social and natural sciences. These include: the limits of identities or universal laws as a basis for forecasts; the corresponding need for simplifying parametric representations of one or more of the variables that enter into identities; various sources of uncertainty about parameterizations; intrinsic limitations on predictability or forecasting accuracy in large-scale systems; the need for sensitivity analyses of model responses to changes in exogenous variables and/or parametric structures; problems of model linkage; and the social (organizational and political) context of forecasts. Suggestions for future lines of inquiry are made in each case. Several of these are such that they can benefit from a sharing of experience and expertise across disciplinary lines.The research reported herein was supported in part by the IC² Institute, The University of Texas at Austin, and in part by National Science Foundation Grant Number SES-8411702. However, the opinions expressed in the paper are those of the authors and do not necessarily reflect those of the sponsoring organizations. We appreciate the advice and comments of Jesse H. Ausubel, Robert S. Chen, Judith Jacobsen, and Richard C. Rockwell on earlier versions of this paper.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

Diagnosis and forecast of the Caspian Sea level with the operational hydrodynamic model

The observational data on sea level at Tyulenii Island station were compared with the results of the Caspian Sea level simulation with the three-dimensional hydrodynamic model with different spatial horizontal resolution (3 and 1 nautical miles). The sea motion is induced by the air pressure gradients and tangential wind stress that are obtained from the COSMO model forecast and specified on the surface. The results of diagnostic calculations of the sea level for June-October 2014 and 60 forecasts for September 2014 demonstrated that the model with the 1-mile resolution meets the simulation accuracy requirements of the Hydrometcenter of Russia and can be used for the short-range forecasting of the Caspain Sea level.     

Verification of mesoscale forecasts in the 2014 Olympic Games region for the first test period. Part I: Verification techniques and polygonal quality assessments of the COSMO model forecasts

Described is a system of verification of mesoscale hydrodynamic forecasts for the territory of Sochi-2014 Winter Olympic Games worked out within the framework of FROST-2014 international project. A technological line comprises the observational and model output databases, the computing verification complex, and the optional program aids for aggregation and visualization of products. The METv4.0 verification complex developed in cooperation with forecasting and research centers of the USA is used as a core. The effectiveness of the verification system is demonstrated with the COSMO model products for the period of December 1, 2011–March 31, 2012. Preliminary assessments of the model potential in forecasting the surface air temperature, the velocity of the scalar wind, and the sea-level air pressure are made with the quality score aggregation over the selected polygons of verification.     

Forecasts in urban transportation planning: Uses,methods, and dilemmas

Legislation and regulation require cities to prepare forecasts of patronage and J. cost when they compete for federal funds with which to build urban rapid transit systems. Experience shows that these forecasts routinely overestimate patronage and underestimate costs. The explanation for this phenomenon is to be found not in technical shortcomings in the forecasting methods, but in the fact that the forecasts are critically dependent on assumptions of key parameters. Assumptions are chosen to produce forecasts which justify projects favored on the basis of local politics. In an environment in which competition for funds is vigorous, effective advocacy becomes more important than objectivity in the use of forecasting methods. This paper reviews forecasting models widely used by transportation consultants, and shows how the models are manipulated in order to promote systems which have been chosen on the basis of political criteria.     

北京地区中尺度数值业务预报的客观检验

对北京地区中尺度数值天气预报客观检验系统的框架和方法进行了详细的介绍，分析了北京地区冬季（2001年11月1日~2002年2月28日）主要预报要素的客观检验结果，在此基础上给出北京地区冬季中尺度数值预报业务的误差特征，并根据检验结果定性地分析了模式预报系统性和非系统性误差的可能来源。结果表明，模式地形的强迫作用是地面和对流层低层预报系统性误差的重要来源；测站高空预报要素的非系统性误差显著，初始时刻存在的误差在积分过程中被进一步放大；对北京 (54511) 单站地面要素预报的检验结果发现，2-m温度预报冬季整体偏低。在系统性误差为主要误差分量时对模式的平均误差进行订正能有效地提高温度预报的准确率。     

Stratospheric circulation in seasonal forecasting models: implications for seasonal prediction

Accurate seasonal forecasts rely on the presence of low frequency, predictable signals in the climate system which have a sufficiently well understood and significant impact on the atmospheric circulation. In the Northern European region, signals associated with seasonal scale variability such as ENSO, North Atlantic SST anomalies and the North Atlantic Oscillation have not yet proven sufficient to enable satisfactorily skilful dynamical seasonal forecasts. The winter-time circulations of the stratosphere and troposphere are highly coupled. It is therefore possible that additional seasonal forecasting skill may be gained by including a realistic stratosphere in models. In this study we assess the ability of five seasonal forecasting models to simulate the Northern Hemisphere extra-tropical winter-time stratospheric circulation. Our results show that all of the models have a polar night jet which is too weak and displaced southward compared to re-analysis data. It is shown that the models underestimate the number, magnitude and duration of periods of anomalous stratospheric circulation. Despite the poor representation of the general circulation of the stratosphere, the results indicate that there may be a detectable tropospheric response following anomalous circulation events in the stratosphere. However, the models fail to exhibit any predictability in their forecasts. These results highlight some of the deficiencies of current seasonal forecasting models with a poorly resolved stratosphere. The combination of these results with other recent studies which show a tropospheric response to stratospheric variability, demonstrates a real prospect for improving the skill of seasonal forecasts.     

On upscaling of rain-gauge data for evaluating numerical weather forecasts

Summary One of the main objectives of numerical weather prediction models is reliable forecasting of heavy rain events. This paper discusses problems and strategies of evaluation of daily rain forecasting with operationally available rain station data. The focus is on spatial upscaling of rain station data to the grid of the direct model output. We show limitations of regression – or smoothing – based upscaling like as done, for example, by Kriging analysis and promote probabilistic upscaling by ensembles of stochastic simulations conditioned to the available observations. These ensembles easily provide uncertainties of daily evaluation and unbiased estimates for second moment comparison statistics. As an evaluation exercise we assess the quality of daily forecasts for Austria (total area: 84,000 km²) with the limited-area model ALADIN (horizontal grid-spacing 10 km). A quasi–operational set-up is compared to a physically enhanced but less well tested and tuned set-up. It is shown that the evaluation uncertainty is large, but with a full year of forecasts available it is possible to conclude that the physically enhanced set-up simulates too much rain and significantly more than the operational version with only small differences in simulated patterns and variability. Corresponding author’s address: B. Ahrens, Institut für Atmosph?re und Umwelt, Johann Wolfgang Goethe-Universit?t Frankfurt, Altenh?ferallee 1, 60438 Frankfurt a.M., Germany     

基于重组降水集合预报的洪水概率预报

采用条件亚正态模型方法,生成了具有包含不同可能性的降水集合预报。为了保持各子流域降水集合预报变量之间的空间相关性,采用集合预报重组方法对降水集合预报进行重新排列。使用重组后的降水集合预报驱动水文模型,实现了淮河上游大坡岭-息县、淮河上游息县-王家坝和汝河-洪河上游3个子流域的12次洪水过程的洪水概率预报,并对1988年9月7日和1991年7月31日两次洪水概率预报进行个例分析。结果表明:相对于单一确定性预报,通过条件亚正态分布模型生成降水集合预报后,再经过Schaake洗牌法空间相关性重新组合的降水集合预报,捕捉洪峰出现时间和流量的能力更强。对洪水概率预报来说,降水概率预报更能达到对未来的水文事件进行最大可能估计的目的,并尽可能综合了降水预报不确定性因素,同时也说明维持变量原有的空间相关特征对于降水概率预报具有重要意义。     

Structure, agency and environment: Toward an integrated perspective on vulnerability

We review five perspectives on human vulnerability to environmental change—biophysical, human ecological, political economy, constructivist and political ecology—and assess their respective strengths and weaknesses. While each of these perspectives offers important insights, and some theoretical convergence is evident, the field remains divided along a number theoretical fracture lines. Two deeply rooted metatheoretical assumptions—essentialism and nominalism—are hindering the construction of a more integrated perspective on vulnerability, one capable of addressing the interrelated dynamics of social structure, human agency and the environment. We conclude by suggesting that an evolutionary perspective on social change, grounded in a critical realist epistemology, provides the best prospect for avoiding the above pitfalls and advancing our understanding of vulnerability.     

民用航空气象观测综述

介绍了民用航空气象观测这一全球大气监测网中的重要观测平台的发展历史，航空气象资料的特点及其在气象业务与大气科学研究中的应用现状，详细分析了航空气象资料的获取、优势、存在的局限和未来的改进方向。指出民用航空飞机观测这一常规大气探测手段具有广阔的应用前景，受到了气象部门和航空业的共同重视，航空气象资料对提高天气预报准确率和气象服务水平将起到积极的促进作用，在未来的数值天气预报业务和大气科学研究中占据越来越重要的地位。