防雹作业指挥中的雷达探测方法

711数字化气象雷达因其操控方便、响应速度快、探测范围满足要求,在我国人工防雹作业指挥中起着重要作用。根据711数字化气象雷达设备的特点,研究快速、全面获取冰雹云回波特征参数及监测冰雹云初始回波的雷达探测方法,通过对不同雷达探测模式对比分析,提出三线切割法。     

Emission-line properties of Seyfert 2 nuclei

This is the third paper of a series devoted to the study of the global properties of Joguet's sample of 79 nearby galaxies observable from the southern hemisphere, of which 65 are Seyfert 2 galaxies. We use the population synthesis models of Paper II to derive 'pure' emission-line spectra for the Seyfert 2 galaxies in the sample, and thus explore the statistical properties of the nuclear nebular components and their relation to the stellar populations. We find that the emission-line clouds suffer substantially more extinction than the starlight, and we confirm the correlations between stellar and nebular velocity dispersions and between emission-line luminosity and velocity dispersions, although with substantial scatter. Nuclear luminosities correlate with stellar velocity dispersions, but Seyferts with conspicuous star-forming activity deviate systematically towards higher luminosities. Removing the contribution of young stars to the optical continuum produces a tighter and steeper relation,   L ∝σ⁴_★  , consistent with the Faber–Jackson law.
Emission-line ratios indicative of the gas excitation such as [O  iii ]/Hβ and [O  iii ]/[O  ii ] are statistically smaller for Seyferts with significant star formation, implying that ionization by massive stars is responsible for a substantial and sometimes even a dominant fraction of the Hβ and [O  ii ] fluxes. We use our models to constrain the maximum fraction of the ionizing power that can be generated by a hidden active galactic nucleus (AGN). We correlate this fraction with classical indicators of AGN photoionization (i.e. X-ray luminosity and nebular excitation), but find no significant correlations. Thus, while there is a strong contribution of starbursts to the excitation of the nuclear nebular emission in low-luminosity Seyferts, the contribution of the hidden AGN remains elusive even in hard X-rays.     

地震引起地球自转速率变化的分析

由地震引起地球内部质量重新分布将影响地球惯量矩的变化，从而引起地球自转速率的变化，即日长的变化。一般说，大地震产生大的附加位移场。它对地球自转特性有较强的影响。本文采用Ｈａｒｖａｒｄ目录中１９７７－１９９４年间的地震有关参数，和根据地震激发地球自转的变化理论及Ｄａｈｌｅｎ和Ｌａｍ－ｂｅｃｋ推出有关公式计算了地震引起地球轴向惯量矩的变化。结果表明：由单个地震引起的日长变化要比观测值小几个量级，它的累积效应表现出长期的变化即日长减小，就是地震活动加速地球自转。地震使地球自转能量随时间稳定地增加。并表明，虽地震活动影响日长，但它不是十年尺度变化的主要原因，它可能是地球自转非潮汐加速机制之一     

新疆伽师强震群震源应力环境分析

本文基于能量辐射系数（Ag)和环境剪应力（τ0）讨论了伽师强震群发生的应力环境背景。1988年以来11年的环境剪应力τ0值表明,伽师震群发生在相对低的应力环境下,1992年以来8年的能量辐射系数Ag值显示震源区介质强度较弱,震中位于介质性质发生变化的过渡区。同时,震源区（喀什）能量辐射系数Ag自1994年5月起系统性地降低,较好地显示了1996年3月19日至1998年8月27日期间震源区发生的10次强震前（包括1996年3月19日阿图什6．9级地震）震源区介质性质的前兆性异常变化,本文由此对伽师强震群的成因进行了讨论。     

Porphyry and Skarn Cu-Mo-Pb-Zn-Ag-Au Metallogeny of the Gangdise Plutonic-Volcanic Arc, Tibet

PORPHYRY AND SKARN Cu-Mo-Pb-Zn-Ag-Au METALLOGENY OF THE GANGDISE PLUTONIC -VOLCANIC ARC, TIBETtheNational973Project“MetallogenicBackgroundandProspectiveEvaluationoftheGangdiseBelt”     

Parameterization of the Absorption of the H2O Continuum, CO2, O2, and Other Trace Gases in the Fu-Liou Solar Radiation Program

The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2, CO, N2O, CH4, and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500-14500 cm^-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and CH4 in the spectral region 2850-5250 cm^-1 are taken as a new singlemixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approaches within the context of the CKD method are small and less than 0.48% for the H20 line and continuum in the 2500-14500 cm^-1 solar spectral region, -1% for H2O (line) H2O (continuum) CO2 CH4 in the spectral region 2850-5250 cm^-1, and -1.5% for H2O (line) H2O (continuum) O2 in the 7700-14500 cm^-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm^-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9%-13% (-12 W m^-2) among which the H20 continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6-9 W m^-2. The new, improved program with the incorporation of the preceding gases produces a smaller solar absorption in clouds due to the reduced solar flux reaching the cloud top.     

华北中南部出现强降水“麦莎”、“珊瑚”登陆我国——2005年8月

8月份,全国大部地区月降水量接近常年同期或偏多.辽宁、湖北、吉林等地的部分地区出现严重暴雨洪涝灾害;西北东北部及内蒙古、黑龙江、湖南等地的部分地区旱情持续或发展.全国大部地区月平均气温接近常年同期.黄淮、江淮、四川盆地及鄂、湘等地的部分地区出现阴雨寡照、低温天气.月内,台风麦莎和强热带风暴珊瑚在我国登陆,造成浙、苏、鲁、沪、闽等地损失严重;局地强对流天气发生频繁.     

玲珑-焦家式金矿床流体包裹体的稀土和微量元素特征

应用热爆提取和 ICP-MS 方法,研究了玲珑-焦家式金矿床脉石英和绢英岩中流体包裹体的微量元素特征。结果表明,流体包裹体中 REE 配分模式均表现为 LREE 富集型,轻、重稀土具有较好的分馏,LREE/HREE=6.07～26.41。但轻重稀土内部分异不明显,(La/Sm)、=2.15～5.11,(Gd/Lu)=0.72～5.24。成矿流体具有弱的 Eu 正异常,δEu=1.05～7.09,与中高温、弱酸性的现代地热成矿系统相似。流体包裹体/中国陆壳元素丰度标准化后表明,流体中富集的重金属元素有 Cu、Mo、Pb、Bi 等,它们的富集系数大于1。成矿流体中亏损的元素有 Ti、V、Cr、Co、Li、Zr、Nb、Th、U 等。流体包裹体微量元素、稀土元素特征为金矿床的成因研究增添了新的证据。玲珑-焦家式金矿床的流体包裹体具相似的 REE 特征,而与其它地区的金矿床或其它类型的矿床则明显不同,说明该区金矿床成矿地球动力学背景相同,都与中生代燕山期构造体制转折条下热液活动有关。     

北半球春季大气臭氧变化特征及其对大气温度和环流场的影响

该文利用美国1978～1993年TOMS臭氧资料以及NCEP提供的全球再分析资料,研究北半球大气臭氧变化特征及其对大气温度和环流的影响.研究表明1987年前后北半球40°N以北的中高纬地区春季大气臭氧柱总量的趋势变化存在明显的突变,大部分地区突然减少,与其相对应的对流层(平流层)平均温度突然升高(降低),300 hPa(30 hPa)层位势高度也突然增高(下降).但是在北大西洋北部和哈德逊湾地区大气臭氧柱总量却突然增加,与其相对应的对流层(平流层)平均温度突然降低(升高),300 hPa(30 hPa)位势高度突然下降(增高),平均温度突然升高(降低 )1～2°C.研究还表明,大气温度和环流的趋势变化主要是由于大气臭氧的趋势变化所引起.另一方面,在同一地区1979～1992年春季大气臭氧柱总量强弱异常年的大气温度场和环流场的差异也存在相同的分布特征,这一事实进一步说明大气臭氧柱总量的多少是决定大气温度场和环流场差异的重要原因.