辽河西部凹陷南段异常低压背景下的成岩动力学研究与成岩相预测

辽河西部凹陷南段古近系砂岩中发育低压-异常低压,泥岩中发育超压。文中考虑低压对砂岩成岩作用的促进作用和超压对泥岩成岩作用的抑制作用,建立了适合于异常压力背景下的成岩作用数值模拟模型,模拟了该区的成岩演化史,预测了成岩阶段和成岩相。结果表明,在断陷期,辽河西部凹陷南段断裂活动强烈,大地热流高,成岩演化快;在裂后期,构造活动弱,大地热流低,成岩演化慢。目前,在深凹陷区沙河街组已进入中成岩阶段B期—晚成岩阶段,主要发育致密储层;在斜坡带沙河街组主要处于早成岩阶段—中成岩阶段A期,发育常规储层。     

地形重力波拖曳参数化对热带气旋强度和路径预报影响的研究

本文在GRAPES_TMM（Global/Regional Assimilation and Prediction System for Tropical Mesoscale Model）——中国南海台风模式版（面向南海和东南亚）中发展和引进了KA95（Kim and Arakawa,1995）地形重力波拖曳参数化方案（GWDO）,并对2012年主要的9个登陆台风进行了试验对比研究,考察了不同标准Richardson数（Ri_c）的GWDO试验对台风路径和强度预报的影响。结果表明,在引入地形重力波拖曳参数化过程后,模式对台风登陆时路径和强度的预报能力均要有提高,对台风预报时长越长,GWDO的影响也更为显著。对双台风“SAOLA”和“DAMREY”试验结果表明,GWDO对台风外围距台风中心150 km的对流层中下层风速减弱较为明显,减弱了GRAPES区域模式对台风强度预报偏强的现象,对台风强度长时间预报改善更为明显。不同标准Ri_c对重力波拖曳力的计算较为敏感,当Ri_c取1.0时,动能迅速的在低层被频散,能量无法有效地上传;Ri_c取0.25时,大部分的能量在中高层被频散。总的来说,Ri_c取0.75时对台风路径和强度预报改进更为显著,其结果可为业务预报提供指导意义。     

Pedogeochemistry of china and its significance in agricultural production

Pedogeochemistry of China is controlled by such factors as biology, climate, parent material, topography and anthropogenesis, and the different geochemical types are formed under the different conditions of soil formation which have different abundance levels of elements. The relationship between concentration of elements and plant growth and human health depends upon available forms of element in soils. While the factors affecting element availability are soil pH and Eh, tillage and fertilization by man besides element forms in soils. On the basis of pedogeochemical types and distribution, rational plantation and application of fertilizer to soils will be of great significance for sustainable development of agricultural production.     

下投探空资料在台风莫拉克路径预报的应用试验

2009年8月7日中国大陆举行了首次利用机载下投式探空仪观测台风的试验,飞机在台风莫拉克与天鹅之间的云带相对稀薄区释放11个下投式探空仪。基于下投探空观测资料、常规探空资料和1°×1°分辨率的NCEP再分析资料,分析下投探空资料的可用性,并以下投探空资料初步分析了两台风间南海上空的风场、湿度场等大气特性;分别进行了有无以同化下投探空为初始场的GRAPES模式的模拟试验,以了解下投探空资料对台风莫拉克预报的影响作用。初步结论表明,台风天鹅与莫拉克之间的南海上空对流层中低层为深厚的西南气流,对流层低层及高层湿度小,中间层大;同化下投探空资料后,观测地区(下投探空点及其附近)800 hPa以下西南风减弱,以上加强,湿度中低层减小;有无同化下投探空资料的初值场差异随模式积分向下游传播,影响台风的环境场,改变了台风的引导气流:同化后500 hPa台风引导气流偏东、偏北分量加强,使台风的路径更接近实况路径,48 h台风路径预报误差比原来减少18%。     

A pedodiversity pattern: taxonomically established soil orders in China

1GeneralsituationofstudyChina is one of the oldest civilized countries in the world. Human activities and the practice of agriculture date back nearly 10 thousands years when people began gaining an understanding and knowledge about soils. Records of these activities can be found in ancient or current Chinese references (Gong etal., 1999), and in non-Chinese literatures like those in English and Russian (Thorp, 1936; Kovda, 1960; Needham, 1986; Li and Cao, 1990; Gong etal., 2003). Soil cl…     

Elemental Geochemistry of a Soil Chronosequence on Basalt onNorthern Hainan Island, China

With increasing soil age, the contents of Sr, Ba and ratios of Sr/Be in soils tend to decrease, whereas the contents of V, Sc, Ni, Cr, Co and ratios of Fe/Ni and Fe/Co tend to increase, as evidenced from a study on soils of different ages, developed on basahs in the northern part of Hainan Island. Ba/Nb, significantly correlative with soil age, can be used to evaluate soil evolution. By using the mass-balance method, the element migration was discussed with Ti as an immobile element. The results showed that element leaching was most intensive in the early pedogenic period. In this period (Primosols) , over 90% of Ca, Mg, K and Na was leached out of soils till Ferrosol formation. The leaching of P occurred mainly at the beginning of soil development. About 60% of Si was mobilized in the stage of Cambosol formation and 80% in the stage of Ferralosol formation.     

岩石节理面形态与水力特性研究

通过节理面粗糙度测量、张开度模拟、节理渗流试验及有限元数值分析,探讨了岩石节理复杂的水力特性。研究表明,节理渗流具有明显的不均匀性、各向异性及与变形耦合等性质,节理的渗透系数与法向应力之间呈负指数关系。     

天山荒漠景观内土壤机械地球化学垒的研究

天山荒漠景观内土壤中存在两种形式的机械地球化学垒,即由水流流速变化形成的机械地球化学垒和由于空气流速变化形成的机械地球化学垒。由于地球化学垒内土壤中粘粒的聚集,使得铁族元素Ｔｉ、Ｖ、Ｍｎ、Ｆｅ、Ｃｏ、Ｃｕ、Ｚｎ及Ｌｉ、Ｋ、Ｂ、Ｆ等元素在其内聚集。Ｂ、Ｃｕ、Ｆｅ等元素的有效性随其全理的增加而增加,Ｆ元素的有效性除与全量有关外,还受其它因素影响,变化效复杂。     

人为土壤有机碳的分布特征及其固定意义

文章在分析不同类型的人为土壤形成过程及其特点的基础上研究了人为土壤有机碳含量、分布年龄与同位素组成特征。结果表明,人为土壤中有机碳的含量分布不同于起源土壤或者相应的非人为土壤,主要体现在有机碳含量降低的缓慢和不规则性以及有机碳含量的相对富集。通过计算证明人为土壤的有机碳密度高于相邻土壤或起源土壤。放射性碳测定表明人为土壤中的有机碳年龄较老,说明了有机碳在这些土壤中存在的相对稳定性。土壤有机碳的稳定同位素组成分析表明,土壤中深层的有机碳与现代有机碳来源不同,也表明了土壤中有机碳的稳定存在。文章还分析了人为土壤中有机碳富集和稳定的可能机制,包括物理、化学和生物学机制,认为就有机碳的固定而言,人为土壤是一种具有最佳管理方式的可持续利用的土壤资源     

Iron loss of paddy soil in China and its environmental implications

Science China Earth Sciences - Iron (Fe) is an important element for the terrestrial and marine ecosystems through its biogeochemical cycling on the Earth’s surface. China has a long rice...