军情密报与信息公开:宋代边报走进新闻传播的途径及影响

宋代边报有广义与狭义之分。广义边报,即沿边政府发出的公文,狭义的边报本质上就是由边疆地区发至中央的机密军情公文。二者相比,后者更能体现出事物的独特性,更具有逻辑价值。狭义边报的内容走进新闻传播分为制度化和非制度化两种途径。制度化新闻传播主要借由邸报录载与出榜示众实现;非制度化新闻传播主要借由民间流言与小报等完成。制度化传播体现当权者宣传、慰抚等目的,实质属于政治传播;非制度化传播满足时人对安全信息的需求,是真正的新闻传播,代表了历史进步的方向。宋代的邸报、小报不仅可以成为边情的有效传递者,还具备了打破封建专制政府信息垄断的潜质,但统治者出于维护旧制度的需要,极力限制它们功能的发挥和正常的发展。宋代边情与新闻的转化机制大体上是失败的,为导致其国防力量衰弱的重要因素之一。本文通过对边报传播现象的分析,发现宋代媒介发达程度与传播开放度、自由度之间的非同步性。这种非同步性与统治集团维护自身狭隘利益密切相关,证明了当时专制主义中央集权制度已经暴露其腐朽、阻碍社会发展的一面。如果放宽历史的视距,宋代又并非中国专制主义中央集权制度衰落期,上述发现恰好为社会领域发展的不平衡性提供了一个历史注解。

论宋代新闻载体的形式及其特征

宋代的新闻载体,既包括代表官方立场的进奏院报状(“邸报”“朝报”)、榜文、边报,也包括出于牟利目的民间小报。朝廷官报由进奏院负责采编,依照定本制度进行新闻内容的严格审查,有助于政令畅通,实施舆论引导。榜文、边报在较小范围内发布应对紧急事态的军政信息,在历史关键时刻可以发挥特殊作用。民间小报满足了广大民众获知政坛内幕的心理期待,产生了广泛影响,也受到了朝廷的查禁。但是它屡禁不绝,打破了朝廷官报的垄断局面,揭开了中国民间办报的序幕。宋朝实现了新闻载体的多元创新,呈现出近代报刊的诸多特征,在中国新闻史上具有重要的历史地位。

EXPERIMENTAL STUDY OF THE ROLE OF INITIAL AND BOUNDARY CONDITIONS IN MESOSCALE NUMERICAL WEATHER PREDICTION

Based on the real case of a frontal precipitation process affecting South China, 27 controlled numerical experiments was made for the effects of hydrostatic and non-hydrostatic effects, different driving models, combinations of initial/boundary conditions, updates of lateral values and initial time levels of forecast, on model predictions. Features about the impact of initial/boundary conditions on mesoscale numerical weather prediction (NWP) model are analyzed and discussed in detail. Some theoretically and practically valuable conclusions are drawn. It is found that the overall tendency of mesoscale NWP models is governed by its driving model, with the initial conditions showing remarkable impacts on mesoscale models for the first I0 hours of the predictions while leaving lateral boundary conditions to take care the period beyond; the latter affect the inner area of mesoscale predictions mainly through the propagation and movement of weather signals (waves) of different time scales; initial values of external model parameters such as soil moisture content may affect predictions of more longer time validity, while fast signals may be filtered away and only information with time scale 4 times as large as or more than the updated period of boundary values may be introduced, through lateral boundary, to mesoseale models, etc. Some results may be taken as important guidance on mesoseale model and its data a.ssimilation developments of the future.

Numerical simulation of an extreme haze pollution event over the North China Plain based on initial and boundary condition ensembles

The North China Plain often su ers heavy haze pollution events in the cold season due to the rapid industrial development and urbanization in recent decades.In the winter of 2015,the megacity cluster of Beijing Tianjin Hebei experienced a seven-day extreme haze pollution episode with peak PM2.5(particulate matter(PM)with an aerodynamic diameter≤2.5μm)concentration of 727μg m 3.Considering the in uence of meteorological conditions on pollu-tant evolution,the e ects of varying initial conditions and lateral boundary conditions(LBCs)of the WRF-Chem model on PM2.5 concentration variation were investigated through ensemble methods.A control run(CTRL)and three groups of ensemble experiments(INDE,BDDE,INBDDE)were carried out based on difierent initial conditions and LBCs derived from ERA5 reanalysis data and its 10 ensemble members.The CTRL run reproduced the meteorological conditions and the overall life cycle of the haze event reasonably well,but failed to capture the intense oscillation of the instantaneous PM2.5 concentration.However,the ensemble forecasting showed a considerable advantage to some extent.Compared with the CTRL run,the root-mean-square error(RMSE)of PM2.5 concentration decreased by 4.33%,6.91%,and 8.44%in INDE,BDDE and INBDDE,respectively,and the RMSE decreases of wind direction(5.19%,8.89%and 9.61%)were the dominant reason for the improvement of PM2.5 concentration in the three ensemble experiments.Based on this case,the ensemble scheme seems an e ective method to improve the prediction skill of wind direction and PM2.5 concentration by using the WRF-Chem model.

Edge Feature Based Fast Mode Decision Algorithm for H.264 Intra Prediction

A fast intra mode decision algorithm is proposed in this paper to reduce the complexity of H. 264 encoder. The proposed algorithm adopted the pre-processing method based on edge feature in pictures to filter out some impossible prediction modes. Context information and pre-computed threshold are used to determine whether it is necessary to check the DC mode. This method is able to get rid of most of candidate modes so that only 66--150 modes are left for the final mode decision, instead of 592 modes in the case of full search （FS） method of H. 264. Simulation results demonstrate that the coding time of the proposed algorithm falls down 71.7% compared with FS method, while the performance loss is trivial compared with FS mode decision scheme.

Evaluation of an ocean data assimilation system for Chinese marginal seas with a focus on the South China Sea

Data assimilation is a powerful tool to improve ocean forecasting by reducing uncertainties in forecast initial conditions.Recently,an ocean data assimilation system based on the ensemble optimal interpolation(EnOI) scheme and HYbrid Coordinate Ocean Model(HYCOM) for marginal seas around China was developed.This system can assimilate both satellite observations of sea surface temperature(SST) and along-track sea level anomaly(SLA) data.The purpose of this study was to evaluate the performance of the system.Two experiments were performed,which spanned a 3-year period from January 1,2004 to December 30,2006,with and without data assimilation.The data assimilation results were promising,with a positive impact on the modeled fields.The SST and SLA were clearly improved in terms of bias and root mean square error over the whole domain.In addition,the assimilations provided improvements in some regions to the surface field where mesoscale processes are not well simulated by the model.Comparisons with surface drifter trajectories showed that assimilated SST and SLA also better represent surface currents,with drifter trajectories fitting better to the contours of SLA field than that without assimilation.The forecasting capacity of this assimilation system was also evaluated through a case study of a birth-and-death process of an anticyclone eddy in the Northern South China Sea(NSCS),in which the anticyclone eddy was successfully hindcasted by the assimilation system.This study suggests the data assimilation system gives reasonable descriptions of the near-surface ocean state and can be applied to forecast mesoscale ocean processes in the marginal seas around China.

Effective approaches to extending medium-term forecasting of persistent severe precipitation in regional models

A set of methods designed to improve （i.e.extend） the medium-term forecasting of persistent severe rainfall （PSR） events in China using the regional Weather Research and Forecasting model are summarized.Simulations show that achieving a more efficient use of large-scale atmospheric variations of the global model and retaining small-scale features in the regional model are critical for better forecasting PSR events.For precipitation,the larger the magnitude and longer the lead time,the more significant the improvement-especially for the methods of spectral nudging and updated initial conditions.In terms of large-scale circulation,the anomaly correlation coefficient can be distinctly improved for 1-5-day lead times by adopting the spectral nudging technique,whereas lateral boundary filtering results in marked improvement for 7-11-day lead times.

PERFORMANCE COMPARISON OF A LINEARLY COMBINED ORDERED-STATISTIC DETECTORS UNDER POSTDETECTION INTEGRATION AND NONHOMOGENEOUS SITUATIONS

Several Constant False Alarm Rate （CFAR） architectures, where radar systems often employ them to automatically adapt the detection threshold to the local background noise or clutter power in an attempt to maintain an approximately constant rate of false alarm, have been recently proposed to estimate the unknown noise power level. Since the Ordered-Statistics （OS） based algorithm has some advantages over the Cell-Averaging （CA） technique, we are concerned here with this type of CFAR detectors. The Linearly Combined Ordered-Statistic （LCOS） processor, which sets threshold by processing a weighted ordered range samples within finite moving window, may actually perform somewhat better than the conventional OS detector. Our objective in this paper is to analyze the LCOS processor along with the conventional OS scheme for the case where the radar receiver incorporates a postdetection integrator amongst its contents and where the operating environments contain a number of secondary interfering targets along with the primary target of concern and the two target types fluctuate in accordance with the Swerling Ⅱ fluctuation model and to compare their performances under various operating conditions.

Correlation Analysis of Gridding of Earthquakes in Datong and Its Surrounding Areas and Implication for Earthquake Prediction

On the basis of the earthquake （gL I〉3.0） catalog in North China from 1970 to 2009, the pattern of temporal and spatial distribution of medium-small earthquakes in Datong and its surrounding areas is studied by correlation analysis with a focus on its anomaly before moderate and strong earthquakes. With different spatial scales, temporal scales and time steps, the spatial distribution of earthquakes is converted to a sequence, then the correlation coefficients between the spatial distribution of medium-small earthquakes in a long-term and a longer time are calculated for the analysis of anomalies before moderate and strong earthquakes. In the study region center on the epicenter of the 1989 Datong- Yanggao earthquake （Ms5. 9） within a radius of less than 0.8~, with the time length of 3600 days, the longer time length of 3700 days, and the time step of 100 days, the correlation coefficient from 1980 to 2009 is steady between 0.94 and 1.00, but there were anomalies with values less than 0. 94 in the 2 years before the 1989 Datong-Yanggao earthquake （Ms 5.9）, the 1991 Datong earthquake （ Ms 5.8） and 1999 Hunyuan earthquake （Ms 5. 6 ）, which indicates the spatial distribution of a medium-small earthquake is very different from steady background seismicity. The implication for earthquake prediction from the anomaly of the correlation coefficient is also discussed with the three conclusions： （1） Before moderate and strong earthquakes in Datong and its surrounding areas, the obvious change of spatial distribution patterns of medium-small earthquake can be a kind of seismic precursor of the 2-year time scale for the prediction of an earthquake＇s time. （2） As the study region is restricted within a radius of less than 0. 8~, the result of correlation analysis is also good for the prediction of an earthquake＇s location. （3） The method of correlation analysis in this paper helps recognize the anomaly of spatial distribution of medium-small earthquake.

Simultaneous bilateral patellar tendon rupture without predisposing systemic disease or steroid use： a case report

There is a dearth of case reports describing simultaneous bilateral patellar tendon ruptures in the medical literature.These ruptures are often associated with systemic disorders such as lupus erythematosus or chronic steroid use.The author describes a case of a 24-year-old man who sustained traumatic bilateral patellar tendon ruptures without any history of systemic disease or steroidal medication.We repaired and reattached the ruptured tendons to the patella and augmented our procedure with allogeneic tendon followed by wire loop reinforcement.One year after operation,the patient regained a satisfactory range of motion of both knees with good quadriceps strength and no extensor lag.The recurrent microtrauma from a history of intense sports activity and a high body mass index may have played an important role in this trauma event.

Challenges and Opportunities in Urban Meteorology Research and Forecast

An international workshop on urban meteorology. observation and modeling, was jointly held by the Institute of Urban Meteorology （ China ） and the National Center for Atmospheric Research （US） in Beijing, October, 2004. The workshop was intended to share recent progress in urban meteorological research, discuss issues related to research and development priorities faced by diverse Chinese institutions, and explore collaboration opportunities between Chinese and US research institutions. This article summarizes the major issues discussed at the workshop, including observation on urban boundary layer, urban landuse modeling, socio-economic impacts of weather and climates, and air quality in urban environment. It includes recommendations for future urban meteorology observational and modeling research, and potential collaborative opportunities between China and US.