数值天气预报业务模式现状与展望

动力统计结合是提高天气、气候预报水平的重要途径之一,关键问题是如何将数值模式与历史资料进行有效结合;相似预报这一传统方法与动力统计的结合是未来提高天气、气候预报水平的一个重要方向,尽管其原理目前仍停留在相似假设基础上且缺乏坚实的物理基础。文中从准确模式的初值问题出发,提出准确模式初值扰动概念,进而发展了动力统计相似集合预报（Dynamical Statistical Analog Ensemble Forecast,DSAEF）理论。DSAEF理论不仅回答了为什么可以进行相似预报,同时还指出了如何进行相似预报,即其原理是利用准确模式来做预报,并采用集合预报的方式实现预报。基于 DSAEF 理论,建立了登陆台风降水动力统计相似集合预报DSAEF_LTP （Landfalling Typhoon Precipitation,LTP）模型,该模型包括4个步骤：台风路径预报、广义初值构建、初值相似性判别和台风降水集合,其中广义初值由影响台风降水的物理因子构成。DSAEF_LTP模型具有可持续发展特性—可通过引入新因子或改善模型参数来改进模型的性能;目前该模型发布了广义初值包含台风路径、登陆季节和台风强度3个物理因子的1.0版和在此基础上改进了“相似区域”和“集合方案”的1.1版。该模型的性能提升很快,已完成的最新版本（1.1版）3次大样本预报试验均显示,与ECMWF、CMA-GFS、NCEP-GFS和SMS-WARMS （上海区域模式）对比,对≥100 mm和≥250 mm台风过程降水预报的TS评分,DSAEF_LTP模型（V1.1）排名第1。今后,围绕广义初值不断改善,研究引入更多影响登陆台风降水的物理因子,DSAEF_LTP 模型的发展前景广阔。     

Primordial black holes

Primordial black holes (PBHs) are a profound signature of primordial cos-mological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are discussed and observational constraints on the PBH spectrum, or effects of PBH evaporation, are shown to re-strict a wide range of particle physics models, predicting an enhancement of the ul-traviolet part of the spectrum of density perturbations, early dust-like stages, first or-der phase transitions and stages of superheavy metastable particle dominance in the early Universe. The mechanism of closed wall contraction can lead, in the inflation-ary Universe, to a new approach to galaxy formation, involving primordial clouds of massive BHs created around the intermediate mass or supermassive BH and playing the role of galactic seeds.     

Gamma-ray bursts from stellar remnants: probing the Universe at high redshift

A gamma-ray burst (GRB) releases an amount of energy similar to that of a supernova explosion, which combined with its rapid variability suggests an origin related to neutron stars or black holes. Since these compact stellar remnants form from the most massive stars not long after their birth, GRBs should trace the star formation rate in the Universe; we show that the GRB flux distribution is consistent with this. Because of the strong evolution of the star formation rate with redshift, it follows that the dimmest known bursts have z  ∼ 6, much above the value usually quoted and beyond the most distant quasars. This explains the absence of bright galaxies in well-studied GRB error boxes. The increased distances imply a peak luminosity of 8.3 × 10⁵¹ erg s⁻¹ and a rate density of 0.025 per million years per galaxy. These values are 20 times higher and 150 times lower, respectively, than are implied by fits with non-evolving GRB rates. This means either that GRBs are caused by a much rarer phenomenon than mergers of binary neutron stars, or that their gamma-ray emission is often invisible to us due to beaming. Precise burst locations from optical transients will discriminate between the various models for GRBs from stellar deaths, because the distance between progenitor birth place and burst varies greatly among them. The dimmest GRBs are then the most distant known objects, and may probe the Universe at an age when the first stars were forming.     

灰色关联理论在国内生产总值构成分析中的应用

国内生产总值能够全面反映全社会经济活动的总规模,是衡量一个国家或地区经济实力,评价经济形势的重要综合指标,世界上大多数国家都采用这一指标.研究国内生产总值的构成对研究国民经济有着重要的贡献.国内生产总值有着众多构成要素,其中包括:农业、工业、建筑业、交通运输仓储及邮电通信业、批发零售贸易及餐饮业、房地产业等等.就国内生产总值的6个主要构成要素,在定性分析的基础上运用灰色关联理论对构成因素进行定量的深入分析.     

On an analytical framework for voids: their abundances, density profiles and local mass functions

We present a general analytical procedure for computing the number density of voids with radius above a given value within the context of gravitational formation of the large-scale structure of the Universe out of Gaussian initial conditions. To this end, we develop an accurate (under generally satisfied conditions) extension of the unconditional mass function to constrained environments, which allows us both to obtain the number density of collapsed objects of certain mass at any distance from the centre of the void, and to derive the number density of voids defined by collapsed objects. We have made detailed calculations for the spherically averaged mass density and halo number density profiles for particular voids. We also present a formal expression for the number density of voids defined by galaxies of a given type and luminosity. This expression contains the probability for a collapsed object of certain mass to host a galaxy of that type and luminosity (i.e. the conditional luminosity function) as a function of the environmental density. We propose a procedure to infer this function, which may provide useful clues as to the galaxy formation process, from the observed void densities.     

赣江流域生态经济价值与生态补偿研究

借鉴生态补偿研究中生态价值当量的思路,构建森林、草地、农业用地、湿地、河流湖泊和荒地6类不同生态系统指标,对赣江流域的生态经济价值进行测算与分析。结合以生态服务功能价值为基本依据的生态补偿,引入经济学中的博弈论,以赣江流域上游的赣州市和下游的南昌市为例,建立流域生态补偿模型。结果表明:基于修正系数下赣江流域2013年的生态价值当量为730.16万,生态经济价值为46.85亿元,各县域的生态价值当量和生态经济价值差异均较大且二者表现高度一致。从生态价值当量看,最小值为赣州市区的2.87万,最大值为宁都县的31.36万;从生态经济价值来看,最大为宁都县的2.04亿元,最小为赣州市区的0.18亿元。空间上看,赣江流域的生态价值当量和生态经济价值存在一定的地域分异规律,上游明显优于中下游,高值区域集中分布在梅江流域的宁都县、兴国县等县域,低值中心分布在除宜春市区外流域内的各个地级市区,其中林地生态系统的贡献最大,比重达58.98%。利用2004—2013年赣州市的GDP数据和环保投入与南昌市的GDP数据,结合博弈论分析得到上下游的补偿额度在91.53亿~113.18亿元之间。     

初论地洼学说的进展与前景

笔者在研究有关文献和参加一些学术会议后发现.地洼学说近十余年来进展显著,科研成果累累.被称为当代最有生命力的学科之一,但系统地研究其成长过程尚欠缺.为了促进地球科学的不断发展。总结经验与教训。扩大学科间的交流.本文重点论述了地洼学说产生的历史背景:进展阶段与特点;发展总体趋势;学说的前景和展望等问题.     

Semi-analytic simulations of galactic winds: volume filling factor, ejection of metals and parameter study

We present a semi-analytic treatment of galactic winds within high-resolution, large-scale cosmological N -body simulations of a Λ cold dark matter (ΛCDM) universe. The evolution of winds is investigated by following the expansion of supernova-driven superbubbles around the several hundred thousand galaxies that form in an approximately spherical region of space with diameter 52  h ⁻¹ Mpc and mean density close to the mean density of the universe. We focus our attention on the impact of winds on the diffuse intergalactic medium. Initial conditions for mass loss at the base of winds are taken from Shu, Mo & Mao. Results are presented for the volume filling factor and the mass fraction of the intergalactic medium (IGM) affected by winds, and their dependence on the model parameters is carefully investigated. The mass-loading efficiency of bubbles is a key factor to determine the evolution of winds and their global impact on the IGM: the higher the mass loading, the later the IGM is enriched with metals. Galaxies with 10⁹ < M _★ < 10¹⁰ M_⊙ are responsible for most of the metals ejected into the IGM at   z = 3  , while galaxies with   M _★ < 10⁹ M_⊙   give a non-negligible contribution only at higher redshifts, when larger galaxies have not yet assembled. We find a higher mean IGM metallicity than Lyα forest observations suggest, and we argue that the discrepancy may be explained by the high temperatures of a large fraction of the metals in winds, which may not leave detectable imprints in absorption in the Lyα forest.