华北植被的光能利用率及其时空变化分析

利用华北地区2007年的NOAA18 1B卫星资料和402个气象站点的观测数据,建立了利用NOAA18 1B卫星资料和气象资料估算光能利用率(Light Utility Efficiency,LUE)的新技术方法,并研究了华北地区植被LUE及其时空变化。结果表明:利用NOAA18 1B卫星资料来估算华北地区植被LUE,效果较好。华北地区植被的年LUE介于0%～1.13%之间,最大LUE为2.83%。北京、河北、天津、山西及内蒙古各省(区)平均LUE依次为0.57%,0.52%,0.47%,0.39%和0.26%。各种植被类型LUE为森林与灌丛为0.35%～0.74%,草原为0.11%～0.35%,农田为0.44%～0.51%,建筑用地为0.30%,荒漠裸地仅为0.02%。华北各省(区)夏季平均LUE为0.52%～1.14%;秋季和春季平均LUE分别为0.16%～0.49%和0.08%～0.31%;冬季的大部分时间LUE极低,接近零。     

局地相似性关系在城市边界层中的适用性验证

利用中国科学院大气物理研究所325 m铁塔在2003年8月期间47和120 m高度上的湍流观测资料,对局地相似性关系在城市边界层的适用性进行了检验。结果表明：47 m高度仍属于城市冠层之上的近地面常通量层,莫宁－奥布霍夫相似性关系基本适用。但120 m高度则基本属于近地面层与自由对流层之间的过渡高度,在该处,相似性关系部分适用。同时,给出了不同的层结稳定度条件下47和120 m高度上的无量纲速度和温度标准差与稳定度之间的局地相关表达式。     

我国燃煤汞沉降的数值模拟

利用CMAQ-Hg(Community Multi-scale Air Quality-Mercury)模式模拟了我国燃煤排放的大气汞在我国区域的沉降分布状况,其中气象模式为MM5.模式中包括了三种价态汞(气态元素汞(GEM)、气态活性汞(RGM)和颗粒汞(PHg))的气相、液相、非均相化学反应过程以及输送、干湿沉降等物理过程.中国燃煤排放的大气汞中RGM所占比例较高,约为58.4%～66.8%,这导致我国汞沉降量较大.模拟结果表明,在我国的西南地区、华东地区以及京津塘地区燃煤汞的沉降较高,在这些区域的沉降通量高达2～6μg m-2mon-1.燃煤大气汞排放形态对汞的沉降有重要影响,减少燃煤汞排放中RGM的比例能够显著降低我国区域汞的沉降通量.     

黑龙江嘉荫地区古近纪早期古气候分析

黑龙江嘉荫地区是在我国范围内最有希望找到确切陆相白垩系一古近系界线的地区之一,定量研究界线附近古气候变迁有助于了解该界线前后的生物灭绝与复苏过程。本文以乌云组含煤段第10层所产20属29种木本双子叶被子植物化石为根据,定量研究了嘉荫地区白垩系古近系界线之后的生物复苏的环境条件。“叶相一气候多变量程序”定量分析结果显示,该区古近纪早期年均温度(MAT)约11．45℃,属暖温带气候类型;“叶缘分析”得出年均降水量(MAP)约为1424mm,林相总体上属混交中生林。     

A Geometrically Exact Formulation for Three-Dimensional Numerical Simulation of the Umbilical Cable in A Deep-Sea ROV System

This paper proposes a geometrically exact formulation for three-dimensional static and dynamic analyses of the umbilical cable in a deep-sea remotely operated vehicle(ROV) system. The presented formulation takes account of the geometric nonlinearities of large displacement, effects of axial load and bending stiffness for modeling of slack cables. The resulting nonlinear second-order governing equations are discretized spatially by the finite element method and solved temporally by the generalized-a implicit time integration algorithm, which is adapted to the case of varying coefficient matrices. The ability to consider three-dimensional union action of ocean current and ship heave motion upon the umbilical cable is the key feature of this analysis. The presented formulation is firstly validated, and then three numerical examples for the umbilical cable in a deep-sea ROV system are demonstrated and discussed, including the steady configurations only under the action of depth-dependent ocean current, the dynamic responses in the case of the only ship heave motion, and in the case of the combined action of the ship heave motion and ocean current.     

Impact of the Subtropical High on the Extratropical Transition of Tropical Cyclones over the Western North Pacific

Recent publications have investigated the interactions between the extratropical transitions （ETs） of tropical cyclones （TCs） and midlatitude circulations; however, studies of ET events have rarely considered the relationship between the storm and the nearby subtropical high. The TC best-track data provided by the Regional Specialized Meteorological Center-Tokyo Typhoon Center of the Japan Meteorology Agency are used in conjunction with the NCEP/NCAR reanalysis data to discuss the potential effects of the subtropical high on ETs over the western North Pacific basin. When the western Pacific subtropical high （WPSH） is weakened and withdrawn toward the east, more TCs follow recurving paths and the midlatitude trough activity is intensified. These changes lead to enhanced ET activity. By contrast, when the WPSH strengthens and extends westward, the number of TCs that follow direct westward paths increases and the midlatitude trough is relatively inactive. These conditions lead to reduced occurrences of ET cases. Abnormal activity of the WPSH should be considered as an important factor in determining ET activity.     

Metallogenic origin of Sipingshan hot spring gold deposit in Hulin of Heilongjiang and its metallogenic mode

Sipingshan gold deposit is gold-bearing sillcalite in type. There only exist a few kinds of sulfide in the ore and it is lower in content. The gold degree is lower. Au is closely related to the Ag,Cu,Pb,As and Hg elements. The upper sillcalite has Eu and Ce negative anomaly,and the lower sillcalite has Eu positive anomaly. however,the hot spring cemented breccia and rhyolite porphyry have Eu negative anomaly;the S isotope component has deep-seated magmatic sulfur and terrestrial sulfate characteristic;and t...     

基于数据矢量特性的MODIS数据几何校正

MODIS探测器的大扫描角多探元并扫方式是造成扫描图像严重畸变的主要根源,应用基于SWATH的卫星遥感数据处理策略,分析MODIS 1B各分辨率数据空间位置关系及图像数据与经纬度数据的对应情况,结合探测器扫描方式、卫星升降轨和地球曲率等各方面因素按像元地理位置合成图像,抛弃数据光栅特性采取矢量特性实现对像元几何精定位。结果表明：应用该种方法处理的MODIS数据几何校正精度高,方便进行亚像元级精确几何校正,而且可以避免2次或多次像素重定位导致信息丢失,不会出现“BowTie”现象。     

东北区域空气质量数值预报模式应用研究进展

中国气象局沈阳大气环境研究在2014年基于CUACE和CMAQ建立了东北区域空气质量数值预报业务系统,本文介绍了空气质量数值模式的研究进展以及业务现状,为东北区域空气质量和雾霾预报提供了技术支撑。然而,随着预报精细化和更长预报时效的业务发展需求,存在预报准确率不高、计算资源短缺、科技创新能力不足等问题。本文基于存在的问题提出了东北区域空气质量数值预报未来发展建议与展望,包括加强大气污染源清单研究与技术规范制定、观测资料同化技术研究与业务应用、物理过程参数化方案的改进优化、发展数值预报产品订正技术、开发高分辨率7—10 d数值预报产品、加强人才引进和科技创新等。     

从气象灾害防御到气象灾害风险管理的管理方法转变

讨论了气象灾害和气象灾害风险的重点研究对象。尝试性地将人类认识气象灾害的过程归纳为4个阶段：气象灾害的启蒙认识阶段、气象灾害的监测与预报阶段、气象灾害的减灾工程阶段和气象灾害的风险管理阶段。同时,引出了气象灾害和气象灾害风险的不同理念。以现在时刻为划分点,将过去已发生的灾害定义为气象灾害,将未来可能发生的灾害定义为气象灾害风险。最后建立了基于SWOT的远期气象灾害风险管理的分析方法,并提出了将人工影响天气作为气象灾害风险管理的气象工程手段的观点。