δ~(18)O, δD and d-excess signatures of ground ice in permafrost in the Beiluhe Basin on the Qinghai-Tibet Plateau,China

In this paper, stable isotope(δ~(18)O, δD) investigations were completed in ground ice from a deep borehole in the Beiluhe Basin on northern Qinghai-Tibet Plateau to unravel the isotopic variations of ground ice and their possible source water. The δ~(18)O and δD of ground ice show distinctive characteristics compared with precipitation and surface water. The near-surface ground ice is highly enriched in heavier isotopes(δ~(18)O and δD), which were gradually depleted from top to bottom along the profile. It is suggestive of different origin and ice formation process. According to isotopic variations, the ice profile was divided into three sections: the near-surface ground ice at 2.5 m is frozen by the active-layer water which suffered evaporation. It is possible that ground ice between 3 and 4.2 m is recharged by the infiltration of snowmelt. From 5 to 6 m, the ground ice show complex origin and formation processes. Isotopic variations from 6 to 11.1 m and 20.55 m indicate different replenishment water. The calculated slope of freezing line(S=6.4) is larger than the experimental value(5.76), and is suggestive of complex origin and formation process of ground ice.     

The geometry of space-time prisms with uncertain anchors

Space-time prisms envelop all spatio-temporal locations that moving objects may have visited between two of their known spatio-temporal locations, given a bound on their travel speed. In this context, the known locations are often the result of observations or measurements, and they are called ‘anchor points’. The classic space-time prism, in isotropic two-dimensional space, as well as in transportation networks, assumes that the measurements of these anchor points are exact. Whereas, in many applications, we can assume that time can be measured fairly precisely, this assumption is unrealistic for the spatial components of measured locations (we think of Global Positioning System (GPS) errors, for instance). In this paper, we extend the classical prism from anchor points to circular ‘anchor regions’ that capture the uncertainty or error on their measurement. We define the notion of a space-time prism with uncertain anchor points, called uncertain prism, for short. We study the geometry of uncertain prisms in an arbitrary metric space to make this concept as widely applicable as possible. We also focus on the rims of uncertain space-time prisms, which demarcate the area that a moving object can have visited between two anchor regions (given some local speed limitations).     

“雪龙”号科考船在冰区航行的船体振动测量研究

船舶在冰区航行时,船体会受到多种类型激振力的作用而产生不同程度的结构振动。船体振动会对船体结构安全以及船上人员的正常工作产生不利影响。船体结构振动的现场测量可较为准确地分析船体振动的基本特性,确定船体振动与外界荷载因素的对应关系。在2015—2016年中国第32次南极科学考察过程中,对"雪龙"号极地科学考察船的冰激振动开展了现场测量。本研究对比了船体在无冰区和冰区航行过程中的船体振动变化,分析了船体在不同航速、冰厚以及不同破冰航行方式下的振动规律。测量结果表明:船体冰激振动随着航速和冰厚的增加而显著增大;在船体采用冲撞式破冰时横向振动最为明显,而在连续式破冰时,垂向振动最为明显。以上研究可为冰区航行中船体振动的现场监测技术提供有益参考,并有助于分析海冰对船体振动规律的影响。     

我国省级太阳总辐射测量标准量值传递的不确定度分析和评估

通过对世界辐射基准传递到我国省级工作级标准总辐射表的不确定度进行分析和评估,确定了量值传递过程中不确定度来源主要包括测量重复性、输出电压值、太阳入射角变化、热偏移以及标准器等引入的不确定度,得出我国省级工作级标准总辐射表校准结果的不确定度为0.6%。我国采用"成分和"法对省级太阳总辐射标准量值进行传递,其标准器引入的不确定度系标准直接辐射表(0.3%)和标准散射辐射表(1.0%)的合成,标准器引入的不确定度所占比例达90%以上,因此提高标准直接辐射和标准散射辐射的测量确定度是减小量值传递不确定度的关键。此外太阳辐射量值传递的准确性受天气条件的影响较大,选择天气稳定,大气透明度高的天气以及太阳高度角大于30°的时段;增加测量次数以减小测量数据的分散性,降低重复性测量引入的不确定度;对被校准总辐射表进行通风,以减小热偏移的影响;保证仪器安装水平以及准确跟踪遮光,可以进一步减小量值传递的不确定度,提高我国短波辐射的测量水平。     

Measurement and Estimative Models of Glacier Mass Balance in China

Attributed to high altitude and inland location, the glaciers in China are characterized by very low temperature. The non-negligible contribution of up to 25% of superimposed ice to the net balance has been taken into account in the mass budget calculation. So too has the internal the accumulation in the infiltration zone of the accumulation area.
The prevailing monsoon climate delivers most of the annual precipitation over glaciated areas of China in the summer, making the major accumulation on those glaciers coincide with the ablation period. Therefore, the annual mass balance should be calculated neither by giving the place of annual accumulation to winter balance, nor annual ablation to summer balance. Rather, it is better done by net accumulation and net ablation during the year. In order to get the annual accumulation and the annual ablation on a glacier, the summer precipitation should be measured at the same time.
Frequent snowfall in the summer season results in intensive fluctuation of surface albedo. This means that, for lack of data on the extremes of ablation, reconstruction of mass balance is unsatisfactory when based on the relationships of accumulation and ablation to precipitation and temperature. The establishment of models, either on the relationship of multi-year mass balance to the equilibrium line and the mass balance gradient of a glacier in steady-state, or on the maximum entropy principle and the hydrometeorological data, helps to estimate the multi-year mass balance of the glacierized area in a mountain range or drainage basin.     

同位素丰度比^12C／^13C与恒星演化及其核过程

近２０年中在银河系及河外星系中同位素丰度比＾１２Ｃ／＾１３Ｃ的毫米波及光学观测取得了一些结果,同位素丰度比＾１２Ｃ／＾１３Ｃ在研究恒星演化及其核过程方面具有重要意义,银河系中的＾１２Ｃ／＾１３Ｃ随银心距ＤＧＣ呈梯度分布,附近河外星系中明显较高的＾１２Ｃ／＾１３Ｃ表明银河系中心处于一个较为宁静的物理相,恒星中不同的＾１２Ｃ／＾１３Ｃ值则反映了各自不同的演化阶段,进一步高精度,大样本的观测将有助于人们     

普通铅同位素演化系统模式

已有的几种普通铅同位素模式仅反映了一些封闭体系铅同位素混合的特殊情况,不便于有效地应用于地质历史时期复杂的地质作用过程。本文应用概率论方法,从理论上分析包括开放体系在内的13种不同系统普通铅同位素混合的23种情况,讨论各种情况下铅同位素资料的地质年代学意义与地质事件发生年代的计算方法,从而建立多阶段铅同位素演化的系统模式。应用读系统模式研究燕山地区的成岩成矿时代,所得结果与其它方法测出的年龄一致。     

区域降水分布定量测量及其在IMGRASS综合试验中的应用方案研究

在综合分析现有地基测量降水时空分布方法及设备条件的基础上,我们选择了雷达－雨量计联合测雨及雷达－辐射计联合遥感降水分布方法作为ＩＭＧＲＡＳＳ综合试验中的降水测量方案。除了介绍方法的原理、探测方案外,还讨论了误差来源及改进措施。     

高精度重力资料在胜利油区油气藏探测中的应用

摘要：应用改进的重力归一化总梯度法（ＧＨ法）对胜利油田ＤＢ区的高精度重力测量资料进行了处理。计算了ＧＨ值在地下的三维分布。某一深度ＧＨ平面等值线图中的闭合极小值（ＧＨ低）反映了低密度体的存在及其水平位置,而不同深度等值线图中ＧＨ低的数目的变化可以近似表示低密度体集中的深度范围。ＧＨ平面等值线图还可以为选择ＧＨ铅垂断面图的方向提供依据。ＧＨ铅垂断面等值线图中的闭合极小值更清楚地显示出低密度体的形态及其近似深度。计算出的ＧＨ值的三维分布与钻井资料的比较表明,ＧＨ的闭合极小值与已知油气藏在位置上有较明显的相关关系。     

黄土高原黄土稳定同位素与古季风研究进展

黄土高原黄土-古土壤完好地记录了过去环境信息,进入90年代以来,在利用碳、氧同位素作为气候替代指标研究古植被、降雨量、古环境温度及古季风演化方面取得了长足的进展,文章就这方面的主要研究成果作了综合分析与评述。