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YanMei Cui SiQing Liu A. ErCha QiuZhen Zhong BingXian Luo XianZhi Ao 《中国科学:地球科学(英文版)》2016,59(6):1292-1298
In space weather forecasting, forecast verification is necessary so that the forecast quality can be assessed. This paper provides an example of how to choose and devise verification methods and techniques according to different space weather forecast products. Solar proton events (SPEs) are hazardous space weather events, and forecasting them is one of the major tasks of the Space Environment Prediction Center (SEPC) at the National Space Science Center of the Chinese Academy of Sciences. Through analyzing SPE occurrence characteristics, SPE forecast properties, and verification requirements at SEPC, verification methods for SPE probability forecasts are identified, and verification results obtained. Overall, SPE probability forecasts at SEPC exhibit good accuracy, reliability, and discrimination. Compared with climatology and persistence forecasts, the SPE forecasts are more accurate. However, the forecasts for SPE onset days are substantially underestimated and need to be considerably improved. 相似文献
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“东半球空间环境地基综合监测子午链”（简称子午工程）是我国空间科学领域开工建设的第一个国家重大基础设施项目。子午工程利用沿东半球120°E子午线附近和北纬30°N附近的15个综合性观测台站,运用无线电、地磁、光学和探空火箭等多种探测手段,连续监测地球表面20—30km以上到几百公里的中高层大气、电离层和磁层,以及十几个地球半径以外的行星际的空间环境参数。它将为我国各类用户提供完整、连续、可靠的多学科、多层次的空间环境地基综合监测数据。子午工程总投资1．67亿元,建设期3年,子午工程整体科学寿命预计超过11年。 相似文献
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The time varying conditions in the near-Earth space environment that may affect space-borne or ground-based technological
systems and may endanger human health or life are referred to as space weather. Space weather effects arise from the dynamic
and highly variable conditions in the geospace environment starting from explosive events on the Sun (solar flares), Coronal
Mass Ejections near the Sun in the interplanetary medium, and various energetic effects in the magnetosphere–ionosphere–atmosphere
system. As the utilization of space has become part of our everyday lives, and as our lives have become increasingly dependent
on technological systems vulnerable to the space weather influences, the understanding and prediction of hazards posed by
these active solar events have grown in importance. In this paper, we review the processes of the Sun–Earth interactions,
the dynamic conditions within the magnetosphere, and the predictability of space weather effects on radio waves, satellites
and ground-based technological systems today. 相似文献
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电离层特征参数的实时获取和分析是电离层空间天气监测预报的重要内容.本文针对电离层频高图参数的实时自动度量和分析问题,提出了一种基于电子浓度高度剖面经验正交函数(Empirical Orthogonal Function, 简称EOF)分析的频高图参数自动度量方法,并将该方法应用到位于北京空间环境观测站(403°N,1162°E)的CADI(Canadian Advanced Digital Ionosonde)数字测高仪观测频高图的实时自动度量和分析上.结果表明,该方法具有较好的可靠性和通用性,能实时自动度量频高图的有关参数并反映相关的电离层变化,可作为电离层空间天气实时监测分析的一种有效手段. 相似文献
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Two methods for initialization of ensemble forecasts are compared, namely, singular vector (SV) and conditional nonlinear
optimal perturbation (CNOP). The comparison is done for forecast lengths of up to 10 days with a three-level quasi-geostrophic
(QG) atmospheric model in a perfect model scenario. Ten cases are randomly selected from 1982/1983 winter to 1993/1994 winter
(from December to the following February). Anomaly correlation coefficient (ACC) is adopted as a tool to measure the quality
of the predicted ensembles on the Northern Hemisphere 500 hPa geopotential height. The results show that the forecast quality
of ensemble samples in which the first SV is replaced by CNOP is higher than that of samples composed of only SVs in the medium
range, based on the occurrence of weather regime transitions in Northern Hemisphere after about four days. Besides, the reliability
of ensemble forecasts is evaluated by the Rank Histograms. The above conclusions confirm and extend those reached earlier
by the authors, which stated that the introduction of CNOP improves the forecast skill under the condition that the analysis
error belongs to a kind of fast-growing error by using a barotropic QG model.
Supported by Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KZCX3-SW-230), National Natural Science
Foundation of China (Grant Nos. 40675030, 40633016) 相似文献
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Improvement of the Noah land surface model for warm season processes: evaluation of water and energy flux simulation 总被引：1，自引：0，他引：1
The Noah model is a land surface model of the National Centers for Environmental Prediction. It has been widely used in regional coupled weather and climate models (i.e. Weather Research and Forecasting Model, Eta Mesoscale Model) and global coupled weather and climate models (i.e. National Centers for Environmental Prediction Global Forecast System, Climate Forecast System). Therefore, its continued improvement and development are keys to enhancing our weather and climate forecast ability and water and energy flux simulation accuracy. North American Land Data Assimilation System phase 1 (NLDAS‐1) experiments indicated that the Noah model exhibited substantial bias in latent heat flux, total runoff and land skin temperature during the warm season, and such bias can significantly affect coupled weather and climate models. This paper presents a study to improve the Noah model by adding model parameterization processes such as including seasonal factor on leaf area index and root distribution and selecting optimal model parameters. We compared simulated latent heat flux, mean annual runoff and land skin temperature from the Noah control and test versions with measured latent heat flux, land surface skin temperature, mean annual runoff and satellite‐retrieved land surface skin temperature. The results show that the test version significantly reduces biases in latent heat, total runoff and land skin temperature simulation. The test version has been used for the NLDAS phase 2 (NLDAS‐2) to produce 30‐year water flux, energy flux and state variable products to support the US drought monitor of National Integrated Drought Information System. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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We consider the prospects for developing a forecast system for space weather (SPW) parameters with the use of home facilities for groundbased observations of solar activity. The space weather forecast can be conventionally divided into three components: (i) the prediction of recurrent, slowly changing events connected with the topology of the large-scale magnetic field, (ii) the estimation of fluxes of UV and high-energy radiation, and (iii) the observation of high-speed phenomena, such as solar flares and eruption processes, and the prediction of their consequences at the the Earth’s orbit. At present, to predict recurrent events, data from regular observations of the large-scale field of the Sun by the solar telescope–magnetographs for operative (realtime) prediction (STOP) are effectively used. To estimate high-energy fluxes, to register eruption events, and to estimate their geoefficiency, data from the patrol optical telescope–spectrographs may be used. Patrol telescopes operate in automatic mode and register the processes with an interval of approximately one minute. To detect eruption processes, we propose a method based on the difference between the intensity values in the wings of chromospheric spectral lines. The results of the use of the observational complex of the Kislovodsk Mountain Astronomical Station for the SW forecast are considered in the paper. 相似文献
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We propose a method based on the local breeding of growing modes (LBGM) considering strong local weather characteristics for convection-allowing ensemble forecasting. The impact radius was introduced in the breeding of growing modes to develop the LBGM method. In the local breeding process, the ratio between the root mean square error (RMSE) of local space forecast at each grid point and that of the initial full-field forecast is computed to rescale perturbations. Preliminary evaluations of the method based on a nature run were performed in terms of three aspects: perturbation structure, spread, and the RMSE of the forecast. The experimental results confirm that the local adaptability of perturbation schemes improves after rescaling by the LBGM method. For perturbation physical variables and some near-surface meteorological elements, the LBGM method could increase the spread and reduce the RMSE of forecast, improving the performance of the ensemble forecast system. In addition, different from those existing methods of global orthogonalization approach, this new initial-condition perturbation method takes into full consideration the local characteristics of the convective-scale weather system, thus making convectionallowing ensemble forecast more accurate. 相似文献
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The definition and abnormality discriminatory criteria of earthquake flow function are introduced in this paper based on the algorithm of Space Increased Probability (SIP). Nine earthquake flow functions were defined by the method. The retrospect test that applied the SIP algorithm with the nonlinear earthquake flow function to 7 earthquakes, which occurred from 1975 to 1989 in Eastern China, with a magnitude of 6 or greater depicted that 6 of the 7 strong earthquakes (86%) were located in the SIP areas, and the SIP covers about 32% of the total research time-space domain. These suggest that the R-value, an effective scale for earthquake forecast, is 54% and may imply that the nonlinear earthquake flow function introduced in this paper can be applied to the intermediate-term earthquake forecast research. 相似文献
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对推进地震预测、预报工作的一些政策问题的讨论 总被引：2，自引：0，他引：2
推进地震预测、预报不能只是地震局工作的改进,国家对待地震预测、预报的工作必须有一个政策的调整。当前地震预测预报工作基本上沿用气象工作的模式,但地震预报和气象预报的水平完全不在一个水平上。地震预测预报工作要把科学研究放到首位,在地震工作的管理体制、财政体制方面都应有一个大的调整。 相似文献
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《Astronomy& Geophysics》2010,51(1):1.05-1.05
In December the British National Space Centre released the results of its Space Exploration Review, which makes the case for increased investment in space as a driver for scientific, technological and societal benefit. 相似文献
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On the basis that hydrological users need to know the forecast uncertainty at the time that the forecast is issued, we computed distributions of radar rainfall forecast uncertainty as a function of forecast lead time, basin size, and forecasted rainfall intensity using data from the US 3-D National Mosaic of radar data. We document how exceptional forecasts such as those of heavy rainfall are generally biased. Since forecast uncertainty is also weather dependent, we tried to find good predictors to help either reduce the forecast uncertainty or better define it. These predictors were based either on characteristics of the current precipitation field or on the performance of the nowcast in the immediate past. The value of some predictors, especially those based on the properties of large-scale rainfall patterns, was significant though modest, the predictors being generally more skillful at characterizing forecast uncertainty than at improving forecast accuracy. 相似文献
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Space physics is a young discipline in Turkey. Since 1970 various national near-Earth space research activities and several
international collaborations have been conducted in Turkey and some of these are continuing. In May 2004 a four-week Graduate
Course on “Space and Atmospheric Physics I and II” was held at the Tübitak Feza Gürsey Institute in Istanbul, Turkey. This
paper explains the background behind this initiative, and gives an introduction to the topics that were covered during the
course, especially emphasizing how solar-terrestrial physics is applied to space weather. During the course the students,
in parallel with the lectures delivered, performed projects based on the curriculum, and using information available on the
Internet and in the literature. A resumé of their results concerning the well-known “space weather” event at the end of 2003
is given. 相似文献
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ABSTRACTAssessment of forecast precipitation is required before it can be used as input to hydrological models. Using radar observations in southeastern Australia, forecast rainfall from the Australian Community Climate Earth-System Simulator (ACCESS) was evaluated for 2010 and 2011. Radar rain intensities were first calibrated to gauge rainfall data from four research rainfall stations at hourly time steps. It is shown that the Australian ACCESS model (ACCESS-A) overestimated rainfall in low precipitation areas and underestimated elevated accumulations in high rainfall areas. The forecast errors were found to be dependent on the rainfall magnitude. Since the cumulative rainfall observations varied across the area and through the year, the relative error (RE) in the forecasts varied considerably with space and time, such that there was no consistent bias across the study area. Moreover, further analysis indicated that both location and magnitude errors were the main sources of forecast uncertainties on hourly accumulations, while magnitude was the dominant error on the daily time scale. Consequently, the precipitation output from ACCESS-A may not be useful for direct application in hydrological modelling, and pre-processing approaches such as bias correction or exceedance probability correction will likely be necessary for application of the numerical weather prediction (NWP) outputs.
EDITOR M.C. Acreman ASSOCIATE EDITOR A. Viglione 相似文献
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Review On The Calculation Of Surface Electric And Magnetic Fields And Of Geomagnetically Induced Currents In Ground-Based Technological Systems 总被引：2，自引：0，他引：2
Risto Pirjola 《Surveys in Geophysics》2002,23(1):71-90
Space weather is a popular and important research topic today. Its origin isin the Sun. Space weather effects extend to the surface of the Earth where theyare usually called GIC referring to geomagnetically induced currents intechnological systems such as electric power transmission grids, oil and gaspipelines, telecommunication cables and railway equipment. GIC are a possiblesource of problems within such systems, and observations have been made sincethe first telegraph systems in the 1800's. This paper is a summary and reviewof present knowledge and of possibilities of modelling GIC in a system.Modelling efforts require a determination of the electric field occurring inconnection with a magnetic storm at the Earth's surface and a calculation ofthe resulting GIC. Different modelling techniques of the electric and magneticfields are evaluated in this paper, and special attention is paid to thecomplex image method (CIM) which is suitable for time-critical purposes likeforecasting of GIC. A discretely-earthed power system and a buried pipelineneed different calculation methods of GIC. The former can be treated by amatrix formalism while the distributed-source transmission line (DSTL) theoryis applicable to the latter. 相似文献
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The proper orthogonal decomposition (POD) method is used to construct a set of basis functions for spanning the ensemble of
data in a certain least squares optimal sense. Compared with the singular value decomposition (SVD), the POD basis functions
can capture more energy in the forecast ensemble space and can represent its spatial structure and temporal evolution more
effectively. After the analysis variables are expressed by a truncated expansion of the POD basis vectors in the ensemble
space, the control variables appear explicitly in the cost function, so that the adjoint model, which is used to derive the
gradient of the cost function with respect to the control variables, is no longer needed. The application of this new technique
significantly simplifies the data assimilation process. Several assimilation experiments show that this POD-based explicit
four-dimensional variational data assimilation method performs much better than the usual ensemble Kalman filter method on
both enhancing the assimilation precision and reducing the computation cost. It is also better than the SVD-based explicit
four-dimensional assimilation method, especially when the forecast model is not perfect and the forecast error comes from
both the noise of the initial filed and the uncertainty of the forecast model.
Supported by the National Natural Science Foundation of China (Grant No. 40705035), National High Technology Research and
Development Program of China (Grant No. 2007AA12Z144), Knowledge Innovation Project of Chinese Academy of Sciences (Grant
Nos. KZCX2-YW-217 and KZCX2-YW-126-2), and National Basic Research Program of China (Grant No. 2005CB321704) 相似文献
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《Journal of Atmospheric and Solar》2002,64(16):1723-1733
The space environment continues to be a major cause of anomalies in communications satellites, in spite of much knowledge gained over the past three decades. The two most common causes of anomalies are surface charging and deep dielectric (dis)charging, but other effects, such as total radiation dose, must be accounted for in the design, particularly of solar arrays and electronics. Many space environments are difficult to predict accurately, for example the peak intensity of the developing Solar Cycle 23, and in particular the radiation dose to be expected from it. The recent Leonid storm provides an example of the extreme variation possible between prediction and reality. Telesat's investigations into space-weather-related anomalies are described, and our approach to minimizing susceptibility of satellites to space weather is outlined. Space environment specifications for procurement contracts are reviewed and some general design guidelines are described. 相似文献
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Since 1998, the Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN) has had an operating heliogeophysical service—the Center for Space Weather Forecasts. This center transfers the results of basic research in solar–terrestrial physics into daily forecasting of various space weather parameters for various lead times. The forecasts are promptly available to interested consumers. This article describes the center and the main types of forecasts it provides: solar and geomagnetic activity, magnetospheric electron fluxes, and probabilities of proton increases. The challenges associated with the forecasting of effects of coronal mass ejections and coronal holes are discussed. Verification data are provided for the center’s forecasts. 相似文献