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热融湖影响下多年冻土退化的数值模拟 总被引:2,自引:0,他引:2
在柱坐标下,运用带相变的数值热传导模型,预测了千年尺度上热融湖对多年冻土退化的影响。预测结果表明,受热融湖的影响,湖底下部及周围多年冻土温度状态发生了较大变化。在湖深相同的情况下,湖底年平均温度越高,对多年冻土的热扰动越明显。当湖底年平均温度等于0℃时,湖底下部及周围多年冻土一般不会形成融化层,只可能引起地温升高;当湖底年平均温度大于0℃时,多年冻土不但温度升高,上限下移,而且可能形成融化层,最终导致多年冻土可能被融穿。湖底年平均温度越高,地温增加越快,融穿多年冻土的时间越短。在湖底年平均温度相同的情况下,水深差异对多年冻土退化的影响不明显。 相似文献
995.
MAPGIS是在地质行业,尤其是在地质图的制作过程中被广泛应用的一种地理信息系统,利用MAPGIS软件制作一张复杂的地质图,其地层颜色的修改和属性的填写是极其繁琐的过程。通过利用点图元、面图元的注释、属性和参数间的关系可以很方便的添写地层颜色,利用投影参数将图元的地理坐标信息方便的挂接为图元的属性,可达到事半功倍的效果。 相似文献
996.
High-rate precise point positioning (PPP) to measure seismic wave motions: an experimental comparison of GPS PPP with inertial measurement units 总被引:2,自引:1,他引:1
Peiliang Xu Chuang Shi Rongxin Fang Jingnan Liu Xiaoji Niu Quan Zhang Takashi Yanagidani 《Journal of Geodesy》2013,87(4):361-372
High-rate GPS has been widely used to construct displacement waveforms and to invert for source parameters of earthquakes. Almost all works on internal and external evaluation of high-rate GPS accuracy are based on GPS relative positioning. We build an experimental platform to externally evaluate the accuracy of 50-Hz PPP displacement waveforms. Since the shake table allows motion in any of six degrees of freedom, we install an inertial measurement unit (IMU) to measure the attitude of the platform and transform the IMU displacements into the GPS coordinate system. The experimental results have shown that high-rate PPP can produce absolute horizontal displacement waveforms at the accuracy of 2–4 mm and absolute vertical displacement waveforms at the sub-centimeter level of accuracy within a short period of time. The significance of the experiments indicates that high-rate PPP is capable of detecting absolute seismic displacement waveforms at the same high accuracy as GPS relative positioning techniques, but requires no fixed datum station. We have also found a small scaling error of IMU and a small time offset of misalignment between high-rate PPP and IMU displacement waveforms by comparing the amplitudes of and cross-correlating both the displacement waveforms. 相似文献
997.
AbstractThis study investigates the terrestrial hydrological processes during a dry climate period in Southwest China by analysing the frequency-dependent runoff and soil moisture responses to precipitation variability. Two headwater sub-basins, the Nanpan and Guihe basins of the West River (Xijiang), are studied to compare and contrast the terrestrial responses. The variable infiltration capacity (VIC) model is used to simulate the hydrological processes. Using wavelets, the relationships between observed precipitation and simulated runoff/soil moisture are expressed quantitatively. The results indicate that: (a) the Guihe basin shows a greater degree of high-frequency runoff variability in response to regional precipitation; and (b) the Nanpan basin exhibits less capability in accommodating/smoothing extreme precipitation deficits, reflected in terms of both higher scale-averaged (for 3–6 months) and time-averaged (for the year 1963) wavelet power of soil moisture.Editor Z.W. Kundzewicz; Associate editor C.-Y. XuCitation Niu, J. and Chen, J., 2013. Terrestrial hydrological responses to precipitation variability in Southwest China with emphasis on drought. Hydrological Sciences Journal, 59 (2), 325–335. 相似文献
998.
Thermoluminescence(TL)in marine carbonate has been proposed as a potential proxy for reconstruction of paleoceanography history,and has already been used in defining the Quaternary environment.However,its availability in the geological time scale,such as Permian,is still on debate.The mass extinction event caused by drastic changes of global marine environment in Middle-Late Permian provides a typical example to testify the applicability of this proxy.Here we measured the natural thermoluminescence of the carbonate-dominating marine sediments collected from the strata through the Guadalupian-Lopingian mass extinction boundary(G/LB)in the Penglaitan Section in Laibin,Guangxi,China.Our results reveal that TL intensities of carbonate are much higher than those of siliceous rocks,which indicates that the carbonate is the main contributor to the TL.The variation of TL intensities are related with Mn and Fe contents in the carbonate lattices while high Mn and low Fe(e.g.,high Mn/Fe ratio)in carbonate will release stronger TL.Due to the better storage of carbonate lattices for original information of Mn and Fe in seawater,thermoluminescence of carbonate-dominating sediments/rocks could sensitively reflect marine environment and biological productivity in geological time scale. 相似文献
999.
为推进土地市场化建设,全面准确地分析、评估当前房地产用地形势,沂源县国土资源局组成专项调查队伍,在短时间内对2004,2005年度沂源县辖区内房地产(商业、住宅)开发用地的数量质量、供应管理和投资销售等进行了一次综合性专项调查。调查中主动与建设、规划、计划、统计、房管等有关部门衔接,采取现场实地调研、电话咨询、与购买客户座谈等方式多渠道获取资讯,确保调查数据和调查结果的准确性、完整性。通过调查摸清了沂源县房地产用地市场价格趋势和市场供需状况,为政府宏观调控房地产市场,制定土地供应计划提供了重要依据,对于稳定房地产市场,促进经济社会发展打下了坚实基础。 相似文献
1000.
Continuous Rapid Deformation (CRD) may be an important precursor before some strong earthquakes with magnitude greater than MsS. 0. This paper shows some characteristics of CRD, and proposes a method for identifying precursory CRD that is closely related to the process of earthquake preparation. From the deformation data in Yunnan-Sichan provinces, we obtained the tilt and strain thresholds of 4.5ms/d and 5 × 10-7/d, respectively. Compared the tilt CRD in this region before 9 earthquakes (short-term fore-shocks and after-shocks not included) with magnitude greater than 5.8 in the period from January of 1990 to May of 2001, we found that 8 earthquakes occurred within 5 months after the CRD with a duration of more than 20 days and a tilt velocity of more than 4. 5ms/d without false prediction, but with one failure in earthquake prediction. For the strain CRD, 5 earthquakes occurred after the CRD; there was no false prediction, but 4 earthquakes unpredicted. We have tried to increase the thresholds, but found either the failure ratio or the rate of false prediction increased, while the success rate not obvious increased. 相似文献