昆明高空大气活动与天文视宁度关系初探

本文初步对比分析了昆明大气探空资料与大气视宁度观测资料之间的相关关系。结果表明，它们之间有着明显的关系和规律，但关系式的确立还需更多的资料分析才能确定。     

大气热力状况在地球自转速度季节变化中的作用

木文根据多年观测资料,计算了各月各层大气南北半球赤道与极地之间和南北半球之间的温度差以及地球自转角速度季节变化值,分析了它们与全球大气角动量以及潮汐引起的日长变化的关系。结果表明,两个半球之间的空气温度差是大气角动量、地球角动量和地球自转角速度产生季节变化的主要原因。     

日长年际变化,ElNino／南方涛动和大气准两年振荡的小波分析

本文采用1964-1993年期间日长变化序列、海平面气压和纬向风速资料，通过小波变换等技术研究分析日长年际变化与ElNino／南方涛动、大气准两年振荡之间的关系．结果表明，日长年际变化与ElNino／南方涛动存在着相似的谱结构，而且ElNino／南方涛动叠加上大气准两年振荡后，与日长变化序列的小波变换时频谱更趋于一致．本文研究结果证实，ElNino／南方涛动和大气准两年振荡的贡献基本能够解释地球自转的年际变化．     

用地球自转的历史观测资料反演大气环流的年际变化特征

运用近代天和气象观测技术所测得的资料证实了，固体地球自转的速率变化与大气角动量之间，在几年以下的时间尺度上是非常符合的。 因此，本作首先探讨际用历史上的地球自转观测资料序列作为表征大气环流的一种数据的可能性，用多级数字滤波方法反演了过去近三个世纪的大气年际变化过程，并揭示了历史上大气活动的某些特征。     

红团簇巨星的光谱分析及其作为I、K波段标准烛光的研究

基于高分辨率、高信噪比光谱观测资料，确定了19颗贫金属红团簇巨星的恒星大气参数，得到样本星4种α族元素(O、Mg、Ca、Si)的化学丰度．讨论了铁丰度与恒星大气参数的相关性以及α族元素丰度随金属丰度的变化，计算了共58颗红团簇巨星在I、K波段的绝对星等，讨论了它们与恒星铁丰度之间的关系．结果表明，在分析铁丰度范围内相对于I波段，K波段的绝对星等与铁丰度的相关性更弱，并且与利用理论模型得到的红团簇巨星I、K波段绝对星等与铁丰度的关系进行了比较与验证。     

Chandler摆动周期和Q值对激发函数估计与比较的影响

用1984-1999年期间的地极坐标序列和两个大气角动量序列。分析了不同Chandler周期和品质因子Q的取值对Chandler摆动周期激发的功率谱密度，以及观测激发与大气激发之间的相干系数和相干相位的影响，结果表明，不同Chandler周期和品质因子Q的取值对观测激发的功率谱密度，以及观测激发与大气激发之间的相干系数有很大影响。因此，在分析Chandler摆动的观测激发与地球物理激发的关系时，不能仅以观测激发与某个地球物理激发序列（如大气激发）的更好逼近来选择Chandler摆动的最佳周期，因为Chandler摆动是多种地球物理激发共同作用的结果。     

大气角动量变化以及对地球自转季节变化的激发

利用日本气象局AMIPⅡ大气数值模式的输出结果，基于BP方法和SP方法计算了1979年至1996年大气角动量变化以及对地球自转季节变化激发的差异。利用最小二乘谐波拟合方法和气候平均图方法，分析了大气角动量的季节变化，并与同时期采用NCEP再分析资料和JMA客观分析资料计算的大气角动量进行比较。     

大气折射母函数方法、大气折射解析解和映射函数

回顾了作为实用天学和大地测量学中基本研究课题之一的大气折射映射函数研究的进展。介绍了近几年上海天台发展的大气折射母函数方法，以及由此导出的大气折射解析解。对如今广泛地应用在空间测量技术中的几种映射函数做出评述；分析了NMF模型的优点和不足之处。介绍了由大气折射母函数方法引出的大气延迟新连分式映射函数和天大气折射的映射函数方法。利用VLBI实验中高度截止角与基线长度重复率的关系、探空气球(radiosonde)观测资料、PRARE资料比较了各种映射函数的结果。特别指出了映射函数方法对天大气折射和光学波段测距精度的改进。讨论了大气折射计算中的主要误差源。     

全国大气水汽含量分布

根据1961～2008年全国210个台站的地面气象要素资料,发现地面水汽压与降水量之间的经验关系,建立了由降水量估算地面水汽压的经验表达式,由此进一步求得天文选址所需考察的大气水汽含量.研究结果表明,不同季节的地面水汽压同降水量之间存在着稳定的函数对应关系,利用各地区的降水量计算出的水汽压,符合当地水汽压的实际测量,所求得的各地区大气水汽含量也均能较好地反映当地长年平均情况.     

地球自转速率的短周期项、大气环流和太阳活动

本文用AR谱分析方法分析了1976—1980年地球自转速率的资料和大气环流的资料,以及用调和分析计算了各周期项的振幅及相位,并计算了大气环流的激发函数。其结果说明:两者存在相应的周期项;北半球的大气环流对自转速率周年项的激励约为60％,对半年项及其他短周期项的贡献约为15％以上。本文对自转速率的不规则变化和太阳耀斑大爆发的关系作了定性的比较。     

An investigation on the relationship between solar irradiance signal from ERBS and 8B solar neutrino flux signals from SNO

In the present work an attempt has been made to investigate statistical association between solar neutrino flux data (both D₂O and Salt data) collected from Sudbury Neutrino Observatory and solar irradiance data detected by Earth Radiation Budget Satellite. To serve the present purpose we have used the Multifractal Detrended Cross Correlation Analysis (MF-DCCA) based on Detrended Fluctuation Analysis (MF-X-DFA) method and the Detrending Moving Average Analysis (MF-X-DMA) which explores the long term power-law cross correlations between above two pairs of data sets. Investigation also has been made to find the frequency and time dependent local phase relationship in each pair of data sets using continuous wavelet transform (CWT) based Semblance Analysis. The Semblance Analysis reveals that there exists positive phase correlation as well as negative phase correlation between solar irradiance and D₂O data at different time sub-intervals. This type of mixed phase correlation is also experienced between solar irradiance and Salt data at different time sub-intervals. The causal relationship between the D₂O and the solar irradiance time series and that between Salt and solar irradiance time series have been revealed using Singular Spectral Analysis (SSA). Calculations indicate that possibly the present solar neutrino flux data (both D₂O and Salt data) is supportive to predict the solar irradiance data but may not the vice versa which in turn suggests that the variability of nuclear energy generation process inside the Sun may influence the solar activity.     

A comparison of the thermal and radar characteristics of Mars

There is a correlation between Martian thermal inertia and radar cross section data centered on +22° latitude. The correlation is strongest with 70-cm radar, except between longitudes 10 and 90° where there is a slight anticorrelation, and gets progressively weaker at 12.5- and 3.8-cm wavelengths, respectively. A correlation is expected because of the dependence of both properties on density, but an increase in the average particle size of the surface with increasing dielectric constant is also required in order to explain the data. This may take the form of an increased number of small rocks. The anticorrelation may result from either the effects of atmospheric dust on the surface temperature or from the effects on radar of local variations in large-scale roughness or scattering by rocks. The relative behavior between the wavelengths can be understood in terms of appropriately sized rocks which act as radar scatterers. The trend of the correlation agrees with the dichotomy of the planet into two types of terrain, as noted in other remote-sensing data, and is consistent with an erosional versus depositional surface nature. Variations in the surface dielectric constant, inferred from the 3.8-cm radar data, can explain discrepancies between 2.8-cm radio emission observations and a simple model based on the global distribution of thermal inertia and albedo.     

An algorithm for a near real-time data processing of GPS common-view observations

Near real-time transfer of GPS common-view data is no longer a problem, but near real-time data processing of the data still calls for study, because it is not yet achieved by the usual smoothing and filtering techniques. Based on the characteristics of the GPS common-view data, a Kalman filtering algorithm is designed for estimating the time difference between two sites, while greatly reducing the observational noise. The algorithm is applied to the time difference between the National Time Service Center (NTSC) of China and the Communications Research Laboratory (CRL) of Japan (Over 2000 km apart), and to that between the CRL and the Korean Research Institute of Standards and Sciences (KRIS) (over 1000 km apart). The root mean square errors of the results obtained by the Kalman filter relative to those obtained from the Circular T of BIPM are less than 2.9 ns and 2.6 ns, in the two cases. Further, it is pointed out that, when multi-site data within a common-view network are available we can further improve the accuracy of the time comparisons by indirect observation adjustment. This statement was justified by application to the data from all three stations, i.e. NTSC, CRL, and KRIS.     

一种新的多变量时间序列数据异常检测方法

介绍了一种通过建立多变量时间序列数据相似度矩阵,对相似度矩阵进行转换以最大化数据之间的相关性,并采用随机游走模型计算数据点之间的连接系数来检测数据点上异常的方法。该方法充分利用了数据之间的相关性,有效减少了数据中不同程度噪声对异常检测的影响,检测过程中的漏报率和误报率明显减少,通过仿真实验验证了该方法的有效性。     

Structure of Saturn's Mesosphere from the 28 Sgr Occultations

We analyze an extensive data set of immersion and emersion lightcurves of the occultation of 28 Sgr by Saturn's atmosphere on 3 July 1989. The data give profiles of number density as a function of altitude at a variety of latitudes, at pressures ranging from about 0.5 to about 20 μbar. The atmosphere is essentially isothermal in this range, with a temperature close to 140 K for an assumed mean molecular weight of 2.135. Owing to favorable ring geometry, an accurate radial scale is available for all observations, and we confirm the substantial equatorial bulge produced by zonal winds of ∼450 m/s first observed in the Voyager radio-occultation experiments. The fact that the bulge is still present at microbar pressures suggests that the equatorial winds persist to high altitudes. According to our radial scale, the 2.4-μbar level, which corresponds to half-flux in the stellar occultations, is at an equatorial radius of 60,960 km. This radial scale is in good agreement with the Voyager radio-occultation data at mbar pressures and allows smooth interpolation of the isothermal structure between the stellar-occultation and radio-occultation regions. We do not have such a smooth interpolation between our data and Voyager ultraviolet occultation data, unless we discard the lowest 200 km of Voyager ultraviolet data. When this is done, we obtain a complete atmospheric model from an equatorial radius of 61,500 km down to an equatorial radius of 60,500 km. This model gives excellent agreement between all 28 Sgr, Voyager, and Pioneer 11 data.     

A search for evidence of solar rotation in Super-Kamiokande solar neutrino dataset

We apply the generalized Lomb–Scargle (LS) periodogram, proposed by Zechmeister and Kurster, to the solar neutrino data from Super-Kamiokande (Super-K) using data from its first five years. For each peak in the LS periodogram, we evaluate the statistical significance in two different ways. The first method involves calculating the False Alarm Probability (FAP) using non-parametric bootstrap resampling, and the second method is by calculating the difference in Bayesian Information Criterion (BIC) between the null hypothesis, viz. the data contains only noise, compared to the hypothesis that the data contains a peak at a given frequency. Using these methods, we scan the frequency range between 7–14 cycles per year to look for any peaks caused by solar rotation, since this is the proposed explanation for the statistically significant peaks found by Sturrock and collaborators in the Super-K dataset. From our analysis, we do confirm that similar to Sturrock et al, the maximum peak occurs at a frequency of 9.42/year, corresponding to a period of 38.75 days. The FAP for this peak is about 1.5% and the difference in BIC (between pure white noise and this peak) is about 4.8. We note that the significance depends on the frequency band used to search for peaks and hence it is important to use a search band appropriate for solar rotation. However, The significance of this peak based on the value of BIC is marginal and more data is needed to confirm if the peak persists and is real.     

Measurement of Kodaikanal white-light images – IV. Axial Tilt Angles of Sunspot Groups

The Kodaikanal sunspot data set, covering the interval 1906–1987, is used in conjunction with the similar Mount Wilson sunspot data set, covering the interval 1917–1985, to examine characteristics of sunspot group axial tilt angles. Good agreement is demonstrated between various results derived from the two independent data sets. In particular, the tendency for sunspot groups near the average tilt angle to be larger than those far from the average tilt angle is confirmed. Similarly the faster residual rotation rate for groups near the average tilt angle is also confirmed. Other confirmations are made for the relationships between latitude drift of sunspot groups and tilt angle, polarity separations, and axial expansion. Evidence is presented that tilt angles averaged over these long time intervals differ between the north and south hemispheres by about 1.4 deg. It is suggested that residual tilt angles show a slight systematic variation with phase in the activity cycle.     

Loss of orbital angular momentum and period changes in Algols

The observational data of Algols have been examined in order to clarify the implication of the assumption concerning the orbital angular momentum loss on their orbital period change. It is found that the agreement between theory and observational data of Algols is much better when a nonconservative approach of evolution is adopted.     

Confidence intervals for the correlation between the gamma-ray burst peak energy and the associated supernova peak brightness

A strong correlation between the gamma-ray burster peak energy and the peak luminosity of the associated supernova was discovered by Li for four GRBs. Despite the fact that the formal significance level of the correlation is 0.3 per cent, the smallness of the data set requires careful further evaluation of the result. Subject to the assumption that the data are bivariate Gaussian, a 95 per cent confidence interval of  (−0.9972, 0.02)  for the correlation is derived. Using data from the literature, it is shown that the distribution of known peak GRB energies is not Gaussian if X-ray flashes are included in the sample. This leads to a proposed alternative to the bivariate Gaussian model, which entails describing the dependence between the two variables by a Gaussian copula. The copula is still characterized by a correlation coefficient. The Bayesian posterior distribution of the correlation coefficient is evaluated using a Markov chain Monte Carlo method. The mean values of the posterior distributions range from −0.33 to about zero, depending on the specifics of the supernova (SN) peak brightness distribution. The implication is that the existing data favour a modest correlation between the GRB peak energy and the SN peak brightness; confidence intervals are very wide and include zero.     

初轨计算中角资料观测误差传播的一些讨论

用非线性规划方法处理初轨计算问题,将观测误差看成参量的微小扰动量。在无摄情况下,建立了非线性规划中的灵敏度分析模型（ｆｈｐ）。由此推导,在无摄情况下关于角资料观测误差对角资料观测真值的影响的误差传播分析公式（一阶近似）。