青藏高原1985年冬季异常少雪和1986年异常多雪的环流及气候特征对比研究

利用青藏高原冬季异常积雪资料对比分析了 1 985年冬季异常少雪和 1 986年冬季异常多雪时期大气环流及热带海洋特征。分析结果表明 ,高原冬季多雪与少雪时中高纬度大气环流显著不同。与此同时 ,低纬热带环流及海洋特征也有明显的差异。探讨了造成这种差异的可能原因。     

Relationship between pulse width and energy in GRB 060124: from X-ray to γ-ray bands

GRB 060124 is the first event that both prompt and afterglow emission were observed simultaneously by the three Swift instruments. Its main peak also triggered Konus-Wind and HETE-II. Therefore, investigation on both the temporal and spectral properties of the prompt emission can be extended to X-ray bands. We perform a detailed analysis on the two well identified pulses of this burst, and find that the pulses are narrower at higher energies, and both X-rays and γ-rays follow the same w–E relation for an individual pulse. However, there is no a universal power-law index of the w–E relation among pulses. We find also that the rise-to-decay ratio r/d seems not to evolve with E and the r/d values are well consistent with that observed in typical GRBs. The broadband spectral energy distribution also suggests that the X-rays are consistent with the spectral behavior of the γ-rays. These results indicate that the X-ray emission tracks the γ-ray emission and the emissions in the two energy bands are likely to be originated from the same physical mechanism.     

关于高速滑坡的几个问题

高速滑坡问题是当前工程地质和环境地质学界极为关注的问题。本文对诸如滑体高速滑动所对应的时空界限、滑体滑动过程所产生的热效应以及空气浮托力等高速滑坡产生机制问题进行了初步探讨。     

Rock magnetic properties and palaeomagnetic results of sediments from a stone implement layer in the Bose Basin,Guangxi

Directional samples were taken to study rock magnetism and palaeomagnetic records from the Dong- sheng profile, which is 5 m thick and on the northwest edge of the Bose Basin. Mineralogy and rock magnetism of typical samples indicate that coarse granular titanomagnetite, and fine-grained hematite, superparamagnetic maghemite formed by pedogenesis are in the sediment, which has undergone many transformative processes during different stages of pedogenesis. Parallel samples were taken for thermal demagnetization (TH) (0 to 680℃) and alternating field (AF) demagnetization (0 to 80 mT) respectively. Experimental results of these two kinds of demagnetization illustrate that there are two or more magnetic components in the samples. Intensity of NRM decreases by almost 60% to 90% rapidly when the temperature ranges from 100℃ to 350℃, with a steady magnetic component. It is impossible to analyze the magnetic components at high temperature because those fluctuate widely when the temperature is higher than 400℃. Steady magnetic components from 100℃ to 350℃ indicate that the remanence was mainly carried by fine-grained hematite formed by pedogenesis, reflecting a change in the geomagnetic field while the magnetite was being oxidized into hematite by chemical weathering after deposition. The formative age of the sediments cannot be obtained by magnetic methods in this profile.     

拉萨地磁台地磁相对记录室磁场梯度对比分析

测量拉萨地磁台观测区内自然地磁场梯度和建成地磁记录室后的地磁场梯度,并测量新建记录室内不同高度磁场梯度,对比分析新建地磁记录室内的磁场稳定性,进而找出潜在干扰源,并采取有效措施予以去除,为产出连续可靠的地磁相对记录数据提供环境条件.     

由岩体失稳讨论地震前兆的复杂性

断层带应变弱化——失稳的地震模式表明,岩体失稳不仅取决于作用的应力水平,而且决定于应变弱化阶段中环境刚度和岩石刚度的相对大小。该模式可能被应用去解释实际观测中出现异常,而其后不发生地震活动的复杂情况。     

南极GPS数据质量分析

以多路径误差和电离层延迟为评价指标,利用TEQC软件和QCVIEW软件对南极埃默里冰架、内陆冰盖、纳拉峡海湾、拉斯曼丘陵的实测GPS数据以及部分IGS站点的数据进行了数据质量分析,得到结论： 1)在同一站点上,L2上的多路径误差总比L1上的多路径误差要大;2)在南极不同环境下的多路径误差不同;3)纬度和太阳活动剧烈程度是影响南极地区GPS数据电离层延迟大小的两个重要因素。     

“95.8”川西大暴雨成因分析

通过对“９５．８”大暴雨过程的全面技术总结，揭示了多种尺度系统间相互作用对产生大暴雨过程的贡献，并指出了云团的发生及其发展源于北方冷空气和南方低空急流持续影响所形成的两个中间尺度垂直环流。     

环境因子及生态补水对乌梁素海“黄苔”年际暴发面积的影响(1986—2021年)

“黄苔”是丝状绿藻大量增殖并漂浮聚集在水面的一种藻类水华,是乌梁素海面临的重大水环境问题之一。本研究基于文献数据整合和Landsat TM/OLI系列卫星影像反演,追溯了乌梁素海近35年(1986—2021年)的水质变化和“黄苔”暴发历程,通过相关性分析和多元线性回归等方法,分析了乌梁素海“黄苔”暴发的年际影响因子。乌梁素海水体化学需氧量、总氮(TN)、总磷(TP)浓度在年尺度上呈下降趋势,但仍处于富营养状态(TLI(∑)>50)。相关性分析结果表明,乌梁素海“黄苔”暴发面积与TP、TN、氨氮、气温呈显著正相关,与出水量、风速、沉水植被面积、入水量呈显著负相关;多元线性回归结果表明,沉水植被面积和出水量是影响乌梁素海“黄苔”暴发面积的主要因子。生态补水工程的实施增加了乌梁素海出入水量,降低了水体TP、TN浓度,也造成沉水植被退化,使“黄苔”暴发的扩张趋势得以遏制。然而,乌梁素海现有营养条件、基质条件仍适宜附着藻生长和“黄苔”暴发。在全球气候变化背景下,气温升高和风力减弱可能会加剧这一现象。建议采取多种措施以防控乌梁素海“黄苔”暴发,如生态补水、外源营养盐管控、沉水植被调控、引水活...     

Distinct groundwater recharge sources and geochemical evolution of two adjacent sub-basins in the lower Shule River Basin,northwest China

Based on analysis of groundwater hydrogeochemical and isotopic data, this study aims to identify the recharge sources and understand geochemical evolution of groundwater along the downstream section of the Shule River, northwest China, including two sub-basins. Groundwater samples from the Tashi sub-basin show markedly depleted stable isotopes compared to those in the Guazhou sub-basin. This difference suggests that groundwater in the Tashi sub-basin mainly originates from meltwater in the Qilian Mountains, while the groundwater in the Guazhou sub-basin may be recharged by seepage of the Shule River water. During the groundwater flow process in the Tashi sub-basin, minerals within the aquifer material (e.g., halite, calcite, dolomite, gypsum) dissolve in groundwater. Mineral dissolution leads to strongly linear relationships between Na⁺ and Cl^? and between Mg²⁺+ Ca²⁺ and SO₄ ^2??+?HCO₃ ^?, with stoichiometry ratios of approximately 1:1 in both cases. The ion-exchange reaction plays a dominant role in hydrogeochemical evolution of groundwater in the Guazhou sub-basin and causes a good linear relationship between (Mg²⁺+ Ca²⁺)–(SO₄ ^2??+?HCO₃ ^?) and (Na⁺+ K⁺)–Cl^? with a slope of ?0.89 and also results in positive chloroalkaline indices CAI 1 and CAI 2. The scientific results have implications for groundwater management in the downstream section of Shule River. As an important irrigation district in Hexi Corridor, groundwater in the Guazhou sub-basin should be used sustainably and rationally because its recharge source is not as abundant as expected. It is recommended that the surface water should be used efficiently and routinely, while groundwater exploitation should be limited as much as possible.