A collaborative study on temperature diurnal tide in the midlatitude mesopause region (41°N, 105°W) with Na lidar and TIMED/SABER observations

The na lidar-observed temperature diurnal tidal perturbations, based on full-diurnal-cycle observations from 2002 to 2008, are compared with tidal wave measurements by the TIMED/SABER instrument to elucidate the nature of diurnal tidal-period perturbations observed locally. The diurnal amplitude and phase profiles deduced by the two instruments are in very good agreement most of the year. However, the lidar-observed diurnal amplitudes during winter months and early spring are considerably larger than SABER observations, leading to the existence of a significant amplitude maximum of 12 K near 90 km in February and a different seasonal structure of temperature diurnal amplitude from the two instruments. The lidar-observed diurnal phase shows propagating wave characteristics during equinoctial months, but exhibit “evanescent wave” behavior in winter months, whereas SABER diurnal tidal phase exhibits propagating diurnal tidal character all year long with small seasonal variation. This anomalous tidal characteristic from the lidar observations repeats almost every winter. The exact mechanism behind this tidal feature is not fully understood, therefore further investigation and more experimental observations are necessary.     

L-M优化算法在爆破振动参数预测中的应用

当前,以振动峰值作为单一爆破振动安全指标的回归经验公式,在国内外爆破工程界得到广泛应用.但由于爆破机理和爆破介质环境复杂,影响因素诸多,很难用一个经验公式把这些因素都考虑进去;再加上回归分析方法固有的局限性(要求数据有较好的分布规律和大样本量),经验公式方法进行振动预测的效果不甚理想(李保珍,1997;陈寿如,2001;张继春,2001).     

Estimation of high-frequency seismic wave radiation on fault plane of 2008 Wenchuan earthquake based on improved empirical Green’s function

A new strategy for inversion of high-frequency wave radiation condition on the fault plan is exhibited. One-dimensional source model of large earthquake was divided into subfaults, each subfault contains a series of subsources to express high-frequency wave radiation. Envelope of large earthquakes can be expressed as a root-mean-squared with combination of envelope attenuation relationship from all subsources. The envelope attenuation relationship is considered as the empirical Green’s function. Distribution of subsources is estimated by envelope inversion. According to this method, the high-frequency (>?1 Hz) wave radiation areas of 2008 Wenchuan earthquake are generally inverted by the differential evolution using acceleration data from 27 near-field stations, while acceleration waveforms of the Lushan earthquake from 43 near-field stations were utilized to create attenuation envelope. High-frequency waves radiated in: (1) surface rupture areas, including Yingxiu and Beichuan areas; (2) close to the boundaries of asperities near Yingxiu, Yuejiashan, Beichuan and Nanba areas; (3) within 30 km length near the fault northeastern tip; (4) around Qingchuan area.

     

内蒙古乌拉特中旗294地区遥感蚀变异常信息提取研究

294地区位于内蒙古中部地槽褶皱系宝音图隆起北东端,是重要的多金属成矿区。研究工作运用遥感技术,结合野外调查资料,对该区围岩蚀变异常信息进行了提取和分析。结果显示,铁染、羟基蚀变异常遥感信息分布于断裂构造的旁侧,以NE向、近EW向呈带状分布,并且与已知矿床(点)具有很好的吻合性。从而证明蚀变异常遥感信息能够指示出成矿的潜在部位,对进一步找矿勘查具有指导作用。     

森林火险气象指数的应用研究

利用全国575个国家级基本气象站1971年1月1日至2005年5月31日的气象观测资料, 选用了5种已得到国际普遍认可或我国国家级预警业务中使用的森林火险气象指数计算方法, 计算了我国长序列的历史逐日森林火险气象指数, 并对这些指数在我国的实际使用效果进行对比分析和应用研究。结果表明: IFFD, INMC, IN, IMN指数可在我国大范围推广使用 (除长江中下游及附近地区), 其中以IFFD指数总体应用效果最好, IMN指数次之。     

Experimental study of three-dimensional breaking wave kinematics

Particle image velocimetry has been used to examine three-dimensional breaking wave kinematics. Two cases of wave breaking were studied. In the first case, the wave field contains a single frequency with a uniform angular spreading within a given range {{ — , .}}. The wave field of the second case consists of a number of frequencies with a uniform angular spreading applied to each frequency. In both cases, the waves are designed such that the wave energy is focused at a given point. The degree of angular spreading has been found to have great effects on the breaking characteristics and kinematics. Two types of breaker were observed, the first being plunging and the second being spilling. Increasing the angular spreading had the effect of making the velocities within the extreme waves larger. The ratio of the crest velocity to the breaking wave speed was approximately unity under both single and multiple frequency conditions, regardless of the angular spreading.     

中国气候与环境演变评估(Ⅱ)：气候与环境变化的影响与适应、减缓对策

 气候与环境变化对我国的影响表现在自然、社会、经济和政治等各个方面。通过对我国气候与环境影响的评估，从生态系统、农业、水资源、重大工程等方面进行了论述。在此基础上，从冰冻圈、生态系统、土地退化、工业、交通、服务业、城市与生活等几个方面进行了气候影响的利弊分析。进而评估了气候变化对我国区域可持续发展的影响，提出了气候变化的适应与减缓对策。     

分形在下庄铀矿田中的应用

本文运用分形理论对下庄地区铀矿床(矿点)的空间分布进行了研究。结果表明,铀矿床(矿点)的空间分布具有统计自相似性的分形特征,分数维可以用来定量描述铀矿床(矿点)的分布规律;应用盒计维数的统计方法计算了铀矿床(矿点)空间分布的分数维D值,并对西、中、东成矿活动区的分数维D值进行了比较,探讨了分数维D值的地质意义。实际资料计算结果显示网格数与标度之间具很好的相关性,其相关系数均达0.98以上。     

新疆阿拉套山花岗岩类的K-Ar和~(40)Ar-~(39)Ar同位素定年

新疆西北部阿拉套山南坡的花岗岩体的４０Ａｒ－３９Ａｒ和Ｋ－Ａｒ定年结果表明它们都是海西期侵入体。侵入活动可分为三个阶段：最早的是东部的岩基,岩性为花岗间长岩和钾长花岗岩,年龄约３０５Ｍａ,而后是西部的二长花岗岩和钾长花岗岩,与钨锡成矿有关,年龄约２９０Ｍａ;最晚的是最西部的二长花岗岩,年龄约２８０～２７０Ｍａ。岩浆活动中心有自东或北东向西或南西迁移的趋势。     

Long-term variability in mesopause region temperatures over Fort Collins, Colorado (41°N, 105°W) based on lidar observations from 1990 through 2007

During 1990–2007, there were 894 lidar observations of nocturnal mesopause region temperatures over Fort Collins, Colorado. In an earlier analysis with data to April 1997, an unexpected episodic warming, peaking in 1993 with a maximum value over 10 K, was reported and attributed to the Mount Pinatubo eruption in June 1991. With all data, long-term temperature trends from a 7-parameter linear regression analysis including solar cycle effect and long-term trends leads to a cooling of as much as 6.8 K/decade at 100 km, consistent with some reported observations but larger than model predictions. Including the observed episodic warming response in an 11-parameter nonlinear regression analysis reduces the maximum long-term cooling trends to 1.5 K/decade at 91 km, with magnitude and altitude dependences consistent with the prediction of two models, Spectral Mesosphere/Lower Thermosphere Model (SMLTM) and Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA). In addition, the mid-latitude middle-atmospheric response to solar flux variability in Thermosphere–Ionosphere-Energetics and Dynamics (TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperatures is presented.