Role of temporal resolution of meteorological inputs for process‐based snow modelling

Accurate snow accumulation and melt simulations are crucial for understanding and predicting hydrological dynamics in mountainous settings. As snow models require temporally varying meteorological inputs, time resolution of these inputs is likely to play an important role on the model accuracy. Because meteorological data at a fine temporal resolution (~1 hr) are generally not available in many snow‐dominated settings, it is important to evaluate the role of meteorological inputs temporal resolution on the performance of process‐based snow models. The objective of this work is to assess the loss in model accuracy with temporal resolution of meteorological inputs, for a range of climatic conditions and topographic elevations. To this end, a process‐based snow model was run using 1‐, 3‐, and 6‐hourly inputs for wet, average, and dry years over Boise River Basin (6,963 km²), which spans rain dominated (≤1,400 m), rain–snow transition (>1,400 and ≤1,900 m), snow dominated below tree line (>1,900 and ≤2,400 m), and above tree line (>2,400 m) elevations. The results show that sensitivity of the model accuracy to the inputs time step generally decreases with increasing elevation from rain dominated to snow dominated above tree line. Using longer than hourly inputs causes substantial underestimation of snow cover area (SCA) and snow water equivalent (SWE) in rain‐dominated and rain–snow transition elevations, due to the precipitation phase mischaracterization. In snow‐dominated elevations, the melt rate is underestimated due to errors in estimation of net snow cover energy input. In addition, the errors in SCA and SWE estimates generally decrease toward years with low snow mass, that is, dry years. The results indicate significant increases in errors in estimates of SCA and SWE as the temporal resolution of meteorological inputs becomes coarser than an hour. However, use of 3‐hourly inputs can provide accurate estimates at snow‐dominated elevations. The study underscores the need to record meteorological variables at an hourly time step for accurate process‐based snow modelling.     

Risk and decision making analyses and applications to the petroleum exploration — A certain PSC area

Risk is a critical factor that an investor must take into account, regardless of where money is invested. Before making important decisions in petroleum exploration, it is standard practice to calculate the expected monetary value for each given prospect. Because of the large uncertainty inherent in decisions that involve large sums of money, the investor needs to exercise prudence. This paper describes an application of calculating the expected monetary value in a mature producing area in the Malacca Strait PSC Contract Area, Indonesia.     

空间数据挖掘技术在土地定级估价中应用

介绍了空间数据挖掘技术和决策树算法。通过对其研究，将可视化空间数据挖掘技术应用于土地定级估价，并介绍了基于Visual C^＋＋ 6．0和ESRI公司的MapObiect 2．0组件技术设计和开发了一个可视化交互空间数据挖掘土地定级估价原型系统。系统采用决策树方法作为数据挖掘方法的基本算法，采用训练与学习相结合实现土地定级估价。阐述了基于决策树空间数据挖掘土地定级估价的系统模型，系统总体框架、主要模块、系统界面及系统实现定级估价的工作流程。该方法是对土地定级估价方法的一种新的探索，是对土地信息系统开发的一种新的尝试，也是土地信息系统智能化发展的一个方向。     

钪─埃铬菁R─氯化十六烷基吡啶─乳化剂OP显色体系及其应用研究

在ｐＨ５６～６４的缓冲介质中，Ｓｃ（Ⅲ）埃铬菁Ｒ（ＥＣＲ）氯化十六烷基吡啶（ＣＰＣ）乳化剂ＯＰ形成蓝色配合物，其组成比ｎＳｃ∶ｎＥＣＲ∶ｎＣＰＣ＝１∶２∶２。配合物的最大吸收波长在６１０ｎｍ处，表观摩尔吸光系数为１７１×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。Ｓｃ质量浓度为０～０２４ｍｇ／Ｌ时遵守比尔定律。拟定的方法结合ＰＭＢＰ萃取分离，测定钨矿及其浸出渣中的微量Ｓｃ，可获满意结果     

Construction of Porphyra yezoensis Pure Line from Protoplasts and Its 18S rDNA Sequence Determination

1　Introduction　PorphyraisthemainobjectforalgafarmingandplaysaveryimportantroleinChinesemarineindus tries.Recently ,therehasbeenagreatlossinPor phyracultivationduetothedegenerationoftheculti var,sothereisanincreasingdemandforgoodPor phyracultivars .Theprerequisiteofthetraditionalbreed ingandbioengineeringresearchofPorphyraistheconstructionofpurelines .Traditionally ,theclassifi cationofPorphyrawasaccordingtotheirmorphologi calcharacteristics .However ,mostmorphologicalfea turesofPorphyraar…     

Construction of Porphyra yezoensis Pure Line from Protoplasts and Its 18S rDNA Sequence Determination

The wild Porphyra yezoensis collected from the Qingdao coast was used to prepare protoplasts by enzyme digestion. The pure line was constructed by cultivating the protoplasts. The 18S rDNA of the P. yezoensis pure line was cloned and sequenced. Sequence analysis was executed for this sequence and other 22 sequences retrieved from GenBank. A phylogenetic tree was constructed using the neighbor-joining method. The results revealed a high diversity of 18S rDNA sequences in genus Porphyra and the considerable variation of 18S rDNA sequences in different strains of the same species P. yezoensis and P. tenera. Significant difference of 18S rDNA sequence was observed between P. yezoensis from Qingdao, China, and the two strains of P. yezoensis from Japan, but the three strains of P. yezoensis formed a stable clade in the phylogenetic tree. These results indicate the possibility of interspecies and intraspecies discrimination of Porphyra using the 18S rDNA sequences.     

星系相互作用的一个结果:环星系形成的数值模拟

通过数值模拟相互作用星系（包括靶星系和入侵星系）的碰撞，研究环星系的形成．由于采用旋涡结构作为靶盘试验星分布函数，不同于Toomre采用一系列同心圆作为试验星的分布函数，模拟得到环的结构比Toomre的模拟更接近于实际环星系．     

陇东地区黄土工程地质特征

陇东位于黄土高原腹地，是典型的黄土地层发育区，地下有丰富的石油天然气资源。结合长庆油田建设项目，根据该区地形地貌及其黄土主要工程地质特征，将该地区分为董志塬区(Ⅰ)、蒲茹马莲区(Ⅱ)、泾川环柔区(Ⅲ)和合道川北区(Ⅳ)4个工程地质区。董志塬区(Ⅰ)主要包括合道川、悦乐以南的广大黄土塬地区，由13个小的黄土塬组成，发育有厚250m左右的完整黄土地层，塬顶地势平坦开阔，是陇东地区的主要工程建设区，为自重湿陷性场地，湿陷等级为Ⅱ～Ⅲ级；蒲茹马莲区(Ⅱ)主要为蒲河、茹河和马莲河的Ⅱ级阶地及阶地与塬间的斜坡地带，该区Ⅰ级阶地不发育，Ⅱ级阶地主要发育晚更新世以来的黄土地层，为非自重湿陷性场地，湿陷等级Ⅱ级，地域狭窄，城市发展空间有限；泾川环柔区(Ⅲ)为泾河、环江和柔远河Ⅰ级阶地，该区Ⅱ级阶地不发育，沉积有全新世的新近堆积黄土，为非自重湿陷性场地，湿陷等级Ⅰ～Ⅱ级，地域狭窄，城市发展空间有限；合道川北区(Ⅳ)为合道川、悦乐以北的广大黄土梁峁区及白于山前缘地带，工程建设条件较差，难以从事大面积工程建设。     

判定树归纳分类法在数据挖掘中的应用

介绍了判定树归纳分类法的概念及基于ID3算法的基本策略,给出通过最高信息增益构 造判定树的数据挖掘算法进行分类的预测模型,对判定树归纳分类法的具体应用给出了实例并作 分析。     

川东北地区水稻镉积累与生态健康风险评价

【研究目的】重金属镉主要通过“土壤-植物”系统进入食物链进而影响人体健康,开展农作物镉积累研究对保障人类健康安全具有重要意义。【研究方法】系统采集了四川省东北部南充市、巴中市、广安市等地的土壤及水稻样品,采用ICP-MS方法检测了土壤和水稻中的镉含量,并运用CART决策树和相关系数法进行了数据分析。【研究结果】结果显示,川东北地区表层土壤镉含量相对较低,为0.071~0.92 mg/kg,平均0.254 mg/kg,几乎所有（99.9%）样品镉含量都低于标准限值;水稻（糙米）镉含量差异性较大,为0.002~0.803 mg/kg,平均0.076 mg/kg,超标率达14.0%;水稻镉超标区成人每日通过稻谷摄入的镉达90.4 μg/d,已超过允许摄入量标准60 μg/d。【结论】土壤镉不超标而农作物镉超标的现象可能与土壤的低pH、低CaO、高SiO₂等特点有关,这一认识对于指导区域内粮食安全生产具有重要指导意义。创新点：土壤和水稻综合调查发现土壤镉不超标但农作物超标的现象,CART和相关系数法分析了其原因。