中国东南部与川渝陕甘地区夏季降水 30～60天CISO的反相现象

利用1979～2010年NCEP/NCAR逐日再分析资料和我国753站逐日降水资料,研究了中国东南部和川渝陕甘地区夏季降水30～60天气候季节内振荡（Climatological IntraSeasonal Oscillation,CISO）的反相现象。结果显示两个区域夏季降水CISO在7月中旬之前存在显著的反相关系,且在传播特征上有明显差异。川渝陕甘地区降水局地低频振荡显著,中国东南部降水CISO北传特征清晰。低频环流分析表明,对流层低层低频槽、脊的更替形成了川渝陕甘地区降水CISO的“驻相”振荡,低频气旋式、反气旋式环流位置的移动则产生了中国东南部降水CISO的北传。CISO垂直环流显示上升支与下沉支正好处于川渝陕甘地区与中国东南部,较好地反映了低频降水在两区域的相反变化。中国东南部、长江中下游与川渝陕甘地区三者之间存在动力学上的关联,这可部分地解释川渝陕甘地区和中国东南部之间降水CISO的反相关系。这种反相关系的形成还与气候态下的西太平洋副热带高压和贝加尔湖附近大陆高压脊的季节内变化有关。揭示中国东南部与川渝陕甘地区之间降水CISO的反相现象对于丰富人们对我国夏季风区低频振荡局地特征的认识和理解降水季节内振荡产生机制有重要意义。     

基于国产卫星数据的矿山遥感监测一体化解决方案——以西藏自治区为例

随着高分辨率国产遥感卫星数据的推广应用,矿山遥感监测必将成为该数据的重要应用领域之一。结合西藏自治区矿山遥感监测工作的特点,以资源一号02C(ZY-1 02C)及高分一号(GF-1)卫星影像为数据源,在ArcGIS环境下,提出并实现了从国产卫星遥感数据管理、增强与校正、信息提取、统计分析以及成果图制作等一体化解决方案。该研究成果有助于推进国产卫星遥感数据在矿山遥感监测领域的应用广度和深度,为大规模开展多期次动态矿山遥感监测工作提供技术支持和应用范例。     

Application of Zr-in-rutile thermometry: a case study from ultrahigh-temperature granulites of the Khondalite belt, North China Craton

Zr-in-rutile thermometry was applied to ultrahigh-temperature (UHT) granulites from three localities, Dongpo, Tuguishan, and Dajing/Tuguiwula of the Khondalite belt, North China Craton. Zr concentrations of analyzed rutiles were detected by LA-ICP-MS and EMP, which display a mutative composition zoning, a large inter-grain variation, a bimodal distribution at around 1,500 and 6,000?ppm, and no relationship with the textural setting (matrix vs. inclusion). These characteristics were likely caused by post-peak diffusional resetting associated with slow cooling rates and the presence of a CO₂-rich fluid. The grains with lower Zr concentrations (~500 to ~3,000?ppm) and temperature estimates (~650 to ~850°C) occur close to or in contact with zircon, which was easily affected by post-peak processes (for example: diffusion, dissolution/reprecipitation). The lowest temperatures (~650 to ~700°C) we obtained represent the closure temperature of Zr-in-rutile. Rutiles with higher Zr concentrations (~3,000 to ~8,000?ppm) and calculated temperatures (~850 to ~1,000°C) were least affected by late resetting, giving near-peak metamorphic temperatures. These temperature results higher than 900°C, even in excess of 1,000°C from the three localities, reconfirm the presence of UHT metamorphism. Our results also suggest that Zr-in-rutile thermometry is valid for ultrahigh-temperature estimates. In addition, there are positive correlations between concentrations of Zr and Hf, Nb and Ta of the investigated rutiles, but the correlations weaken as the concentrations increase, especially for Nb and Ta, implying fractionation of Nb and Ta.     

莎车盆地蒸发岩及盐矿物特征初探

莎车盆地喀什皮拉里剖面岩矿扫描电镜及能谱仪分析表明,大量石膏岩中含有石盐、钙芒硝、杂卤石、天青石、白云石及钾镁硫酸盐组合,说明盆地已达到钾镁盐化学沉积阶段,是成钾找钾重要线索,值得研究关注.     

Sorption and desorption behavior of lead on a Chinese kaolin

The sorption and desorption of Pb on kaolin from Suzhou, China were investigated. The sorption experiment was conducted in a 0.01 M NaNO₃ aqueous solution with respect to the effects of initial Pb concentration, pH, solid/solution ratio, and temperature. Langmuir and Freundlich models well described equilibrium isotherms of Pb sorption. Less than 5% of Pb sorbed was desorbed with 0.01 M NaNO₃ extraction, suggesting a dominant specific sorption of Pb. As the initial pH increased, the sorption of Pb on the kaolin increased. More than 60% of Pb was sorbed at pH 2.69 far below the point of zero net charge of the kaolin at 4.2, indicating a mechanism of Pb inner-sphere complex or by chemisorption. Lead sorption decreased with increasing temperature, indicating a process of exothermic sorption.     

基于有限元方法对鲆鲽网箱耐流特性的数值模拟

鲆鲽网箱结构在海中受到水流的冲击作用会发生运动与变形,针对鲆鲽鱼特有的栖底习性,为确保网底结构的稳定有必要对其进行动力分析。为此利用有限元方法建立了流场中网箱受力和变形的数学计算模型,运用该数学模型对底框中加有支撑管结构并装配方形网目网衣的鲆鲽网箱整体位移进行了数值模拟。数值模拟结果表明,网箱的网衣部分在水流作用下形态变化比较大,网底的水平位移与垂直位移随流速的增加而增大,而网箱的底框架在不同流速条件下均能保持在水平位置,且未发生明显的倾斜。由此可见,此类鲆鲽网箱具有较好的耐流性能。     

Scale issues of wetland classification and mapping using remote sensing images: A case of Honghe National Nature Reserve in Sanjiang Plain,Northeast China

Wetland research has become a hot spot linking multiple disciplines presently. Wetland classification and mapping is the basis for wetland research. It is difficult to generate wetland data sets using traditional methods because of the low accessibility of wetlands, hence remote sensing data have become one of the primary data sources in wetland research. This paper presents a case study conducted at the core area of Honghe National Nature Reserve in the Sanjiang Plain, Northeast China. In this study, three images generated by airship, from Thematic Mapper and from SPOT 5 were selected to produce wetland maps at three different wetland landscape levels. After assessing classification accuracies of the three maps, we compared the different wetland mapping results of 11 plant communities to the airship image, 6 plant ecotypes to the TM image and 9 landscape classifications to the SPOT 5 image. We discussed the different characteristics of the hierarchical ecosystem classifications based on the spatial scales of the different images. The results indicate that spatial scales of remote sensing data have an important link to the hierarchies of wetland plant ecosystems displayed on the wetland landscape maps. The richness of wetland landscape information derived from an image closely relates to its spatial resolution. This study can enrich the ecological classification methods and mapping techniques dealing with the spatial scales of different remote sensing images. With a better understanding of classification accuracies in mapping wetlands by using different scales of remote sensing data, we can make an appropriate approach for dealing with the scale issue of remote sensing images.     

Upscale feedback of high-frequency winds on seasonal SST change over the tropical western North Pacific during boreal summer

Climate Dynamics - Present study compares the contribution of low-frequency (> 90-day) and high-frequency (< 90-day) variation-related latent heat flux (LHF) to seasonal...     

近7年蒙自自动站与人工站气温差异对比分析

利用蒙自站2003～2009年自动站与人工站的逐时气温平行观测资料,对两种仪器的观测值进行了对比差值及其均方根、标准差及不确定度、粗差率、一致率等方面的对比分析,并对自动站观测气温序列进行了显著性检验。结果表明:由于两种仪器气温的感应元件、测温原理和观测方式不同,造成两种观测数据存在差异,人工观测值普遍小于自动观测值。偏差存在明显的日变化,白天大于夜间,夏季的偏差明显高于其他季节,超出了+0.2℃的正常范围。自动站观测的气温值与历史序列中的气温值无显著性差异。由于两者在部分时次或月份还存在较大偏差,在业务应用时还需时行较长时间的平行观测,并对其进行均一性分析和客观订正。     

Characteristics of dynamic strain and strength of frozen silt under long-term dynamic loading

The dynamic strain and strength of frozen silt under long-term dynamic loading are studied based on creep tests. Three groups of tests are performed (Groups I, II, and III). The initial deviator stresses of Groups I and II are same and the dynamic stress amplitude of Group II is twice as that of Group I. The minimum value of dynamic stress in Group III is near zero and its dynamic stress amplitude is larger than those of Groups I and II. In tests of all three groups there are similar change trends of accumulative strain, but with different values. The accumulative strain curves consist of three stages, namely, the initial stage, the steady stage, and the gradual flow stage. In the tests of Groups I and II, during the initial stage with vibration times less than 50 loops the strain amplitude decreased with the increase of vibration times and then basically remained constant, fluctuating in a very small range. For the tests of Group III, during the initial and steady stages the strain amplitude decreased with the increase of vibration times, and then increased rapidly in the gradual flow stage. The dynamic strength of frozen silt decreases and trends to terminal dynamic strength as the vibration times of loading increase.