文安MS5.1地震前区域形变异常研究

对2006-07-04文安MS5.1地震前2001~2004年区域GPS站速度场和应变率场使用刚性-线弹性运动模型拟合处理的结果进行研究,获得文安MS5.1地震的1~3 a期的前兆异常。结果表明,地震发生在异常区高异常体发育的边缘梯度带的转折处。     

成都市城市热岛效应分析

城市热岛效应是城市气候最显著的特征之一。基于地理信息系统和不同时次的遥感影像,探讨成都市地表温度、热岛强度、热岛等级的分布特征及其演变。结果表明:成都市热岛效应明显且夜间夏强冬弱,地表温度呈条状分布;日间城市多数区域属于弱热岛以上等级,中心城区偏向强热岛和极强热岛,夜间强热岛面积扩张,冬季热岛等级增加明显;2002~2012年,城市热岛等级增加,强热岛面积扩张,但存在昼夜和季节性差异。     

爆炸应力波作用下缺陷介质裂纹扩展的动态分析

采用透射式焦散线测试系统,进行爆炸应力波作用下缺陷介质裂纹扩展试验,研究了含与炮孔共线的预制裂隙介质裂纹扩展速度、加速度、裂纹尖端动态应力强度因子和动态能量释放率的变化规律以及它们之间的变化关系。试验结果表明,在爆炸应力波作用下裂隙两端产生了两条翼裂纹A、B,翼裂纹A的长度较翼裂纹B长,两条翼裂纹向相反的方向扩展;在翼裂纹扩展过程中,存在着加速与减速的过程,扩展速度瞬间达到峰值,其后逐渐振荡下降;动态应力强度因子也呈现瞬间达最大值到逐渐减小连续振荡变化的趋势,动态应力强度因子 > ;翼裂纹尖端的动态能量释放率对裂纹扩展具有驱动作用。     

Advances in radiative transfer

This review describes advances in radiative transfer theory since about 1985. We stress fundamental aspects and emphasize modern methods for the numerical solution of the transfer equation for spatially multidimensional problems, for both unpolarized and polarized radiation. We restrict the discussion to two-level atoms with noninverted populations for given temperature, density and velocity fields. Unfortunately this article was originally published with typesetter's errors: The correct publication date was 25 February 2006, not 3 January 2006. The content was not in the final form. The publishers wish to apologize for this mistake. The online version of the original version can be found at /10.1007/s00159-005-0025-8.     

On the possibility of investigation of the magnetic field structure in subphotospheric layers of the Sun according to observations of sunspot torsional oscillations

A method of investigation of the magnetic field structure in subphotospheric layers of the Sun has been developed. The method is based on observations of the torisonal oscillations of single sunspots. Characteristics of the torsional oscillations have been obtained from observations of the longitudinal magnetic field and radial velocities of seven single sunspots in the photospheric line Fe I λ5253 Å. The parameters of the torsional oscillations and magnetic tubes in the deep layers have been determined. The radius of the cross section of a magnetic flux tube forming a sunspot is greatest near the Sun’s surface and is approximately equal to the radius of a sunspot umbra. Down to the deeper layers, it decreases quite quickly. The longitudinal electric current appearing in the magnetic tube changes direction. The typical time of the current changes is determined by the period of the torsional oscillations. The intensity of the longitudinal magnetic field in the tube increases with depth. The Alfven wave velocity averaged over the length of a magnetic tube is tens or hundreds of times less than this velocity in a sunspot umbra. It decreases with an increase in the period of oscillations. A decrease in the Alfven wave velocity leads to an increase in the twisting angle of magnetic field lines.     

Geoeffective Analysis of CMEs Under Current Sheet Magnetic Coordinates

Using 100 CME–ICME events during 1997.01–2002.11, based on the eruptive source locations of CMEs and solar magnetic field observations at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to statistically study the characteristics of the CME–ICME events and the corresponding geomagnetic storm intensity. The transit times of CMEs from the Sun to the Earth are also investigated, by taking into account of the angle between the CME eruption normal (defined as the vector from the Sun center to the CME eruption source) and the Sun-Earth line. Our preliminary conclusions are: 1. The distribution of the CME sources in our CMC system is obviously different from that in the ordinary heliographic coordinate system. The sources of CMEs are mainly centralized near the heliospheric current sheet (HCS), and the number of events decreases with the increment of the angular distance from the CME source to the HCS on the solar surface; 2. A large portion of the total events belong to the same–side events (referring to the CME source located on the same side of the HCS as the Earth), while only a small portion belong to the opposite–side events (the CME source located on the opposite side of the HCS as the Earth). 3. The intense geomagnetic storms are usually induced by the same–side events, while the opposite side events are commonly associated with relatively weak geomagnetic storms; 4. The angle between the CME normal and the Sun–Earth line is used to estimate the transit time of the CME in order to reflect the influence of propagation characteristic of the CME along the Sun–Earth direction. With our new prediction method in context of the CMC coordinate, the averaged absolute error for these 100 events is 10.33 hours and the resulting relative error is not larger than 30% for 91% of all the events.     

大质量年轻星体新的C18O(1-0)发射

利用紫金山天文台青海观测站13.7米的毫米波望远镜对74个大质量年轻星体或候选进行了C^18O(1-0)的谱线观测。在63个源中观测到了C^18O(1-0)发射，其中57个天体第一次探测到C^18O(1-0)谱线发射。根据谱线辐射温度（TR^*)和半宽（△V），利用LTE方法计算了每个测量源的C^18O(1-0)发射的光学厚度和C^18O(1-0)分子的柱密度。讨论了^13CO(1-0)和C^18O(1-0)的谱线强度比和积分强度比。     

鄂尔多斯盆地都思兔河流域白垩系含水层特征及供水前景分析

在鄂尔多斯盆地都思兔河流域供水水文地质详查的基础上,通过水文地质钻探、抽水试验、样品分析等手段,查明了流域含水层的结构、埋深以及含水层和隔水层在水平和垂直方向上的变化规律,探讨了各含水层之间的水力联系,并求取了含水层的水文地质参数;对比圈定了包乐浩晓、巴彦布拉格、好勒包勒吉3处富水区;采用地下水流数值模拟方法对上述3处富水区地下水开采量进行计算,提出了27种地下水开采方案,并经过对比得到地下水开采推荐方案。结果表明:包乐浩晓、巴彦布拉格、好勒包勒吉3处富水区主要补给为侧向径流及大气降水入渗补给,排泄方式以潜水面蒸发及向河流排泄为主;在地下水浅埋区,结合含水层单井涌水量的大小,确定采用管井开采方式、中段悬挂式非完整井结构,平均布井,井深300m,单一开采白垩系环河组的地下水,最大限度夺取潜水蒸发排泄量;根据推荐方案,上述3个富水区总开采量达到123 500m3/d,可为该地区地下水资源开发与利用提供技术保障。     

近40a中国不同量级降水对年降水量变化的影响性分析

采用1968-2007年全国595个气象台站的日降水资料,将降水量分为0．1～9．9mm、10～24．9mm、25～49．9mm和≥50mm共4个不同量级降水,通过趋势系数等统计诊断方法,分析了年雨日与年降水量相关性、年雨日与日平均降水强度的变化趋势、不同量级降水的日数和强度的变化趋势以及它们分别对年降水量变化的影响。...     

黄河口及其邻近水域强壮箭虫密度的时空分布及其与环境因子的关系

为探究强壮箭虫（Sagitta crassa）在黄河口及其邻近水域的时空分布特征及其与生物和非生物环境等因子的关系,本文依据2013—2014年在黄河口及其邻近水域6个航次的调查数据,采用丛生指标（I）、聚块性指标（A）和负二项分布参数的倒数（C_A）等聚集指标,分析了强壮箭虫的空间分布特征;应用广义可加模型（GAM）研究了强壮箭虫密度的时空分布和环境因子的关系。结果表明,黄河口及其邻近水域强壮箭虫平均密度为21.85 ind/m3,春、秋季高,冬、夏季低;其密度的空间分布以黄河入海口附近水域为密集中心,向远岸水域逐渐降低;强壮箭虫在黄河口及其邻近水域的聚集特征随密度的变化存在两次聚集和两次扩散;水深、表层水温和浮游桡足类密度是影响其密度时空分布的主要因子,总偏差解释率为55.11%,强壮箭虫密度随水深的增加而减小,随表层水温的升高先增加后减小,随桡足类密度的增加而增加。强壮箭虫密度受黄河口及其邻近水域环境因子变动的影响,具有明显的季节变化和空间分布规律。