中国区际价值链协作的网络特征与空间格局及其演变——基于增加值分解和复杂网络的分析

利用增加值分解和复杂网络分析方法,基于2007年、2010年和2012年的省际投入产出表,构建中国区际价值链协作网络,考察区际价值链协作的网络特点与空间格局及其演变。结果表明,中国区际价值链协作存在显著的网络特点,显示出小世界网络特征;各地区的网络中心性有明显的地区差异,且该差异在不断缩小,而工业化水平等是引起节点网络中心性地区差异的重要因素。节点聚类和社区划分的结果发现,中国区际价值链协作网络存在3~4个网络社区,地区间的局部网络互动显著;且各网络社区内部的节点地区表现出显著的空间毗邻与地理成片,特别是上海等8个地区在网络中的局部互动最为稳定。     

Star formation and clustering in the Hubble Deep Field

We have derived a complete and reliable flux limited sample of15 μm selected galaxies in the ISO-HDF. These galaxies have been shown to produce a large fraction of the Cosmic Infrared Background. From their mid-infrared luminosities, we deduce their star formation rates, and compare then to the ones that can be derived from their radio emission. We find excellent agreement, except for a few objects that are known to be AGN-dominated from their X-ray properties. We show that our sample is more strongly clustered than optical samples, and discuss the constraints it puts on hierarchical models of galaxy evolution. This revised version was published online in September 2006 with corrections to the Cover Date.     

鲜切花高产优质气象影响因子分析

以主要鲜切花品种马蹄莲、香石竹为材料，用常规观测气象资料与其产量波动和质量进行相关分析。结果表明：日照时数和气温对笠年春季出花数有滞后作用。马蹄莲花茎高度与日平均气温１０～２５℃有效积温成对数关系，达优质花高度还需一定营养体大小。气温和日照时数对香石竹产量波动有一定影响     

察尔汗盐湖首采区晶间卤水水化学分异特征的统计研究

本文应用系统分析观点、数理统计方法研究了察尔汗盐湖首采区晶间卤水分异的特征，认为晶间卤水的分异是在外部环境系统作用下，盐湖卤水系统整体发展、演化的结果。     

Association between winter temperature in China and upper air circulation over East Asia revealed by canonical correlation analysis

Canonical correlation analysis (CCA) was used to study the relationship between the winter temperature in China and the circulation at 500 hPa over East Asia. CCA identifies a number of paired patterns that depend on Principle Component (PC) truncation of the two fields. Retaining more PCs usually gives more physically meaningful CCA patterns, but the leading paired pattern has often less explained variance. When fewer PCs are adopted, the leading pattern possesses larger variance. However, it is often distorted in comparison with PC or rotated PC patterns. Various combinations with different PC and CCA patterns remained were tried, which shows that retaining as many PCs as possible and using the first several CCAs instead of only the first give most reasonable connection mechanisms. A statistical downscaling model based on CCA modes linking temperature with circulation was established to quantify the extent to which temperature variation can be explained by circulation. The model was optimised by varying numbers of the PCs and the CCA modes retained. With 13th PC truncation in the circulation and 8th PC truncation in the temperature as well as five CCA modes retained, the optimal CCA model is achieved based on cross-validation. The optimal downscaling model accounts for 47.5% temperature variance on average. However, there is a remarkable regional difference, which ranges from 10% to 70% in brier-based score (BBS). It is concluded that 500-hPa circulation is strongly linked to surface temperature in parts of the country, but it alone is not sufficient to achieve a successful statistical downscaling of the temperature for whole China.     

利用层次聚类对移动曲面拟合滤波算法快速分类的研究

经典移动曲面滤波算法由于算法简练,适用范围广泛且滤波效果较好,适用于多种地形。但是传统移动曲面滤波方法存在较多缺陷,如计算阈值参数难以确定、各个格网间阈值参数缺少相关性、分类主要依据高差阈值及水平距离相关性较小等缺点。文中提出层次聚类算法,将三维地形转换为二维平面,利用相邻点水平距离和高差构建数据集,进行聚类判断点云的属性,采用ISPRS提供的15组样本,定性和定量分析本算法的滤波精度。为验证本聚类算法的优越性和科学性,同时与改进型移动曲面和PTD滤波算法进行精度对比,充分说明本算法相较于其他算法的优越性和高效性。     

Statistical issues in astrophysical searches for particle dark matter

In this review statistical issues appearing in astrophysical searches for particle dark matter, i.e. indirect detection (dark matter annihilating into standard model particles) or direct detection (dark matter particles scattering in deep underground detectors) are discussed. One particular aspect of these searches is the presence of very large uncertainties in nuisance parameters (astrophysical factors) that are degenerate with parameters of interest (mass and annihilation/decay cross sections for the particles). The likelihood approach has become the most powerful tool, offering at least one well motivated method for incorporation of nuisance parameters and increasing the sensitivity of experiments by allowing a combination of targets superior to the more traditional data stacking. Other statistical challenges appearing in astrophysical searches are to large extent similar to any new physics search, for example at colliders, a prime example being the calculation of trial factors. Frequentist methods prevail for hypothesis testing and interval estimation, Bayesian methods are used for assessment of nuisance parameters and parameter estimation in complex parameter spaces. The basic statistical concepts will be exposed, illustrated with concrete examples from experimental searches and caveats will be pointed out.     

基于TIGGE多模式降水量预报的统计降尺度研究

利用TIGGE资料中欧洲中期天气预报中心、美国国家环境预报中心、英国气象局以及日本气象厅4个中心,1~7 d预报时效的降水量预报资料,以TRMM/3B42RT降水量作为"观测值",对东亚地区降水量进行统计降尺度处理。首先利用逻辑回归方法将天气分为有雨和无雨,再对有雨的情况,利用线性回归方法对插值后的预报结果进行降尺度订正,最后将4个中心的预报值进行消除偏差集合平均,得到多模式集成的降水量预报场。结果表明:逻辑回归能够有效地改善预报中小雨的空报情况,统计降尺度订正后的预报结果比直接插值更加准确,多模式集成的预报效果优于单模式结果,其改进效果随预报时效的延长逐渐减小。     

南京雾-霾天气个例湍流运动特征的对比研究

利用超声风速仪、能见度仪等探测资料,采用Fortran、Matlab、Origin等软件处理数据并绘图分析,对比了南京郊区2013年12月4日一次霾过程、2013年12月7—9日一次雾过程和2013年12月3日一个晴天的湍流运动特征。结果表明,霾天和晴天平均水平风速、平均动能、湍流动能、湍流强度、摩擦速度、动量通量和热量通量都有明显的日变化,而这些参量在雾天没有明显的日变化,不同天气湍流参量大小有差异;霾、雾、晴天近中性层结下,u、v、w三个方向风速归一化标准差近似为常数,霾天分别为3.15、2.72、1.17,雾天分别为3.11、2.45、1.25,晴天分别为3.40、3.45、1.50;不稳定条件下霾、雾、晴天风速归一化标准差和湍流动能归一化标准差符合1/3幂次律,稳定条件下霾、雾、晴天无因次湍流动能均满足1/3幂次律;不稳定条件下霾、雾、晴天温度和湿度归一化标准差满足-1/3幂次律,稳定条件下霾、雾、晴天温度归一化标准差符合-2/3幂次律;雾天归一化u、v、w谱与Kansas谱吻合度比霾天和晴天高,霾天u、v、w谱峰值频率约为0.01 Hz,雾天u谱峰值频率约为0.004 Hz,v、w谱峰值频率约为0.1 Hz,晴天u、v、w谱峰值频率约为0.01 Hz。得出结论:雾天的边界层结构与霾天和晴天有所不同;不稳定条件下霾、雾、晴天风速、湍流动能、温度、湿度归一化标准差均符合莫宁-奥布霍夫相似理论;雾天归一化u、v、w谱比霾天和晴天更加符合莫宁-奥布霍夫局地各向同性理论,且霾天和晴天以机械湍流为主,雾天既有机械湍流也有热力湍流。