西北内陆河流域典型生态系统通量数据空间代表性研究

涡度通量数据的空间代表性问题是影响其数据质量不确定性的重要原因。选取了我国西北地区具有代表性的四个通量观测站生长季数据,采用FSAM模型对各站点通量贡献源区范围以及通量贡献最大值点进行了计算,给出了在不稳定与稳定两种大气层结条件下各站点源区的主要分布范围(P=80%):盈科站源区范围相对最小(90~200 m);阿柔站源区范围约为(120~140 m);关滩站源区范围约为(500~600 m);敦煌站源区范围约为(140~280 m)。同时结合各站点仪器架设高度以及不同的下垫面生态环境等因素,对通量源区的变化进行了初步分析,仪器的架设高度直接影响涡度源区范围;不同的下垫面生态环境形成不同的近地面湍流状态进而对通量源区的分布产生间接影响。结果表明各站点观测的通量信息基本均来源于所感兴趣的研究区域。     

鲁西北地区土地现实生产力调查与估算

以鲁西北地区县级1∶5万土壤类型图图斑作为基础评价单元,根据农户现有的投入水平,采用“调查法”模拟分析农业土地资源的现实生产力,并与统计资料和“机制法”模型模拟结果进行对比分析。研究结果表明,现实投入水平下鲁西北地区夏玉米单产略高于冬小麦单产,对冬小麦的投入从整体上来看相当于中等投入,但又存在着区域差异。对夏玉米的投入具有南北向的差异,由南到北投入水平逐渐降低。鲁西北地区土地现实生产力以宁津县最高,庆云县最低,与“机制法”模型模拟结果比较,各县市之间土地生产潜力差距较大。由此可以说明,各县市土壤质量本身对土地年生产力的大小起着重要作用,进一步证明“调查法”能充分反映土壤在土地综合性质中的主要作用。     

南海西北部海区声速垂向及断面分布特征

根据南海西北部海区2012年2月实测的CTD资料计算出该海域的声速,给出了声速的垂向分布的几种类型和断面的分布状况以及它们的一些重要特征.并根据浅海声速跃层标准(ΔC/ΔH≥0.5/S),讨论了本海域声速跃层的分布状况.     

晋西北地区气候变化及其对土地沙漠化的影响

利用晋西北5个代表站近50 a逐月的气温、降水资料,建立了年和冬、夏半年的平均气温、降水序列,分析了晋西北近50 a来气温、降水变化特征。结果表明,晋西北总的气候变化存在暖干化趋势,年和冬、夏半年平均气温变化倾向率分别为0.202 ℃/(10a)、0.2 ℃/(10a)和0.132 ℃/(10a);夏半年气候变暖缓慢且具有阶段性特点;年和冬、夏半年降水变化倾向率分别为-16.68 mm/(10a)、0.404 mm/(10a)和-14.95 mm/(10a);年降水的减少主要由夏半年降水的减少引起,冬半年降水有增多的迹象;夏半年降水减少,减弱了流水对表层土壤的冲刷,冬半年降水增多,一定程度上减缓了土地沙漠化过程。     

湘西北寒武纪黔东世乔氏节头虫Arthricocephalus chauveaui Bergeron 1899的再研究

节头虫属Arthricocephalus 的概念和异名问题得到了新的厘定和更正：过去所认为的“Arthricocephalus”属中的绝大部 分种应归入小掘头虫属Oryctocarella,而似节头虫属Arthricocephalites 则是Arthricocephalus 的晚出异名。根据采自湖南湘西花 垣县子腊村一些Arthricocephalus 处于不同个体发育时期的化石标本,研究并对比前人的材料后发现,诸如胸节数不同等区 别很可能是由于处于个体发育不同阶段所致,而非属种间的差异,因此提出目前节头虫属的各个种整理归并至乔氏节头虫 Arthricocephalus chauveaui Bergeron 1899一种中,进而根据节头虫属与其它掘头虫类三叶虫形态和地层上的比较,讨论其演 化关系。     

Structural Evolution of the Eastern Qiulitagh Fold and Thrust Belt,Northern Tarim Basin,China

The eastern Qiulitagh fold and thrust belt (EQFTB) is part of the active Kuqa fold and thrust belts of the northern Tarim Basin. Seismic reflection profiles have been integrated with surface geologic and drill data to examine the deformation and structure style of the EQFTB, particularly the deformational history of the Dina 2 gas field. Seismic interpretations suggest that Dongqiu 8 is overall a duplex structure developed beneath a passive roof thrust, which generated from a tipline in the Miocene Jidike Formation, and the sole thrust was initiated from the same Jidike Formation evaporite zone that extends westward beneath the Kuqatawu anticline. Dongqiu 5 is a pop-up structure at the western part of the EQFTB, also developed beneath the Jidike Formation evaporite. Very gentle basement dip and steep dipping topographic slope in the EQFTB suggest that the Jidike Formation salt provides effective decoupling. The strong deformation in the EQFTB appears to have developed further south, in an area where evaporite may be lacking. Since the Pliocene, the EQFTB has moved farther south over the evaporite and reached the Yaken area. Restoring a balanced cross-section suggests that the minimum shortening across the EQFTB is more than 7800 m. Assuming that this shortening occurred during the 5.3 Ma timespan, the shortening rate is approximately 1.47 mm/year.     

DUST FALL IN THE TAKLA MAKAN DESERT OF CHINA

The Takla Makan Desert is one of the supposed sources of eolian deposits in the eastern China and the North Pacific Ocean. Lack of direct measurements hinders the theoretical interpretation of material exchange between the atmosphere and land surface as well as the sediment budget of the region. From 1992 to 1994, four measuring sites were established in the vicinity of 84°E meridian along a 380 km observation traverse from the northern margin to the central desert. Data were collected on quantities of dust fall and sedimentary characteristics of airborne sediments, including grain-size distributions as well as chemical and mineral compositions. The quantities of annual dust fall were 10² to 10³ tons km^-2 yr^-1, increasing from the margin toward the central desert. Monthly concentrations of particles finer than 0.02 mm in diameter ranged from 0.06 to 1.25 mg m^-3 over the three-year observation period. The elemental ratio and the element enrichment factor ruled out the Takla Makan Desert as possible sources of the dust in Hawaii and Alaska. The mean geometric diameter of airborne sediments in the 4 to 8 m surface layer from the Luntai oasis was 0.038 mm and from the interior ranged 0.064 to 0.067 mm being moderately to poorly sorted. Weight percent of particles finer than 0.063 mm in diameter were from 83.5% to 47.7%, decreasing toward the central desert. Distributions of the airborne particles were unimodal with peak diameters of 0.06 to 0.07 mm in the central desert and 0.02 to 0.06 mm in the sites toward the edge of the desert. [Key words: dust fall, sedimentary characteristics, Takla Makan Desert.]     

黔西北地区地下水赋存规律及开发利用方向

黔西北地区地处乌蒙山区岩溶发育强烈,地下水系统小型多样、条件复杂,地下勘查找水及开发利用难度大。本文通过对三种不同岩溶流域类型区地下水赋存规律及岩溶发育的综合研究,提出了不同类型系统中勘查找水和开发利用的方向建议,对该类区中地下水资源勘查找水和开发利用工作有一定的指导意义。     

粤西北霜日的年际变化与大气环流异常的关系

利用1964-2006年测站观测资料和NCEP/NCAR再分析资料分析了粤西北霜日的年际变化特征,及其与大气环流异常的联系.结果表明:粤西北的霜日主要集中于12月和1月;从1986年之后年霜日呈明显的递减趋势.并且粤西北的西部和南部线性递减较快;粤西北地区12月和1月霜日偏多、偏少年的大气环流异常特征相似;12月和1月...     

越南西北部大象山超高温变质岩的发现及其区域构造意义

越南西北部大象山群孔兹岩系中发育一套含刚玉+尖晶石+石榴石+夕线石组合的富铝岩石块体,它们呈透镜状包体形式赋存于孔兹岩系内。岩石中刚玉+尖晶石+石榴石+夕线石组合的发育指示岩石经历了超高温变质作用的改造。其中尖晶石和石英的共生组合表明了变质温度高于900℃,而利用岩石退变质矿物组合中的黑云母-石榴石温度计,黑云母-斜长石-石榴石-石英组合温度-压力计估算的变质温度压力条件分别为879~917℃、0.90~0.94GPa。岩石中的早期刚玉+夕线石的组合的存在说明岩石变质作用已经从高角闪岩相进入到了麻粒岩相;而峰期变质矿物组合尖晶石+石英的出现,指示了变质温度高于900℃的超高温变质作用。另一方面,退变质过程中钛铁矿的发育表明岩石经历了快速抬升降压的过程。变质作用的P-T轨迹分析揭示出岩石经历了早期同步升温增压后的快速增温达到峰期条件,后经历快速等温减压过程。这种温压条件的变化与板块会聚过程中由于俯冲板片的断离而使软流圈上涌造成热异常的温压条件变化基本一致。通过对超高温变质岩石进行锆石SIMS U-Pb测年获得的结果大于58Ma,推测这次超高温变质与喜马拉雅运动中印度与欧亚大陆的初期会聚-碰撞作用相关。