强风条件下海面拖曳系数和粗糙长度研究

进一步研究强风条件下海-气湍流动量交换以及海浪特征,有助于提高数值天气模式对台风强度演变、移动路径以及恶劣海况的预报能力。依照前人的方法将台风分为风向与浪向(1)相同,(2)相反,和(3)交叉3个扇形区,并结合台风路径数据,得到了浮标数据相对于台风的方位。分别对3种类型的浮标数据进行分析,进而发现了波浪高度和相速度随风速增加而变化的规律。并利用GWW参数化方案计算出摩擦速度(u_*)、拖曳系数(C_DN)和粗糙长度(z₀)。将这些结果与前人代表性的研究论文中所用观测数据和所得研究结论进行比较,结果表明二者有较强的一致性。该研究证明GWW参数化方案在强风条件下依然有很好的适用性。     

Aerodynamic Characteristics of the Crest with Membrane Attachment on Cretaceous Pterodactyloid Nyctosaurus

The Nyctosaurus specimen KJ1 was reconstructed under the hypothesis that there is a membrane attached to the crest;the so-called headsail crest.The aerodynamic forces and moment acting on the headsail crest were analyzed.It was shown that KJ1 might adjust the angle of the headsail crest relative to the air current as one way to generate thrust (one of the aerodynamic forces,used to overcome body drag in forward flight) and that the magnitude of the thrust and moment could vary with the gesture angle and ...     

南京地区稻田蒸散的研究

引进半经验模式计算稻田蒸散，仅需要常规气象资料和作物的叶面积资料即可较精确地估算农田蒸散，解决了用Ｐｅｎｍａｎ－Ｍｏｎｔｅｉｔｈ方法计算误差偏高以及需要风速梯度观测等在实际应用中存在的困难。通过对模式进行参数的敏感性分析，证实了模式的可靠性和可行性。分析稻田蒸散发现水稻一生有两个耗水高峰：拔节期和抽穗开花期，此时的气象条件最有利于水稻蒸散的进行。     

The bulk aerodynamic formulation over heterogeneous surfaces

This interpretative literature survey examines problems with application of the bulk aerodynamic method to spatially averaged fluxes over heterogeneous surfaces. This task is approached by tying together concepts from a diverse range of recent studies on subgrid parameterization, the roughness sublayer, the roll of large inactive boundary-layer eddies, internal boundary-layer growth, the equilibrium sublayer, footprint theory and the blending height. Although these concepts are not completely compatible, qualitative scaling arguments based on these concepts lead to a tentative unified picture of the qualitative influence of surface heterogeneity for a wide spectrum of spatial scales.Generalization of the velocity scale is considered to account for nonvanishing heat and moisture fluxes in the limit of vanishing time-averaged wind speed and to account for the influence of subgrid mesoscale motions on the grid-averaged turbulent flux. The bulk aerodynamic relationship for the heat flux usually employs the surface radiation temperature or, equivalently, the temperature from the modelled surface energy budget. The corresponding thermal roughness length is quite variable and its dependence on available parameters is predictable only in special cases.An effective transfer coefficient to relate the spatially averaged surface fluxes to spatially averaged air-ground differences of temperature and other scalars can be most clearly defined when the blending height occurs below the reference level (observational level or first model level). This condition is satisfied only for surface heterogeneity occurring over horizontal scales up to a few times the boundary-layer depth, depending on the stability and height of the reference level. For surface heterogeneity on larger scales (small mesoscale), an effective transfer coefficient for the spatially averaged flow must be defined, for which predictive schemes are unavailable. For surface variations on large mesoscales, homogeneous subareas may be maintained where traditional similarity theory is locally applicable. Surface variations on these scales may generate thermally-driven mesoscale motions.     

近海层大气湍流通量系数研究

根据１９９４年９月１８～３０日南沙群岛海域渚碧礁的近海面大气湍流观测实验资料,分别计算了该海域光滑海面和粗糙海面上的空气动力粗糙度（ｚ０ ）、中性曳力系数（ Ｃ Ｄ Ｎ）。利用 Ｂｕｔｓａｅｒｔ 的假定,推导了求取标量粗糙度（ｚ Ｔ、ｚ Ｑ）、整体输送系数（感热交换系数 Ｃ Ｈ Ｎ、水汽交换系数 Ｃ Ｅ Ｎ ）的一组公式。在此基础上,分别计算和分析了该海域光滑海面和粗糙海面上空气动力粗糙度（ｚ０ ）、标量粗糙度（ｚ Ｔ、ｚ Ｑ ）、中性曳力系数（ Ｃ Ｄ Ｎ）、整体输送系数（感热交换系数 Ｃ Ｈ Ｎ、水汽交换系数 Ｃ Ｅ Ｎ）及其关于水平风速分量的分布,并得到了一些有益的结论。     

洞穴事故分析及防范措施探讨——以英、美国为例

通过对英、美等国家洞穴事故的分析,认为洞穴探险事故的发生主要由洞穴地形险峻或岩石崩落、疾病和低体温、洞穴水、被困和失散等原因造成。洞穴事故发生时间多在春、夏、秋季节; 15～ 34岁年龄段发生频率较高,其中以20～ 24岁年龄段发生频率最高。洞穴事故除了可能造成人员低温、极度疲倦和溺水等伤害外,往往造成四肢、头部或躯干损伤,其中以小腿、踝关节外伤最为多见。根据发达国家的洞穴探险经验,文中还讨论了防范洞穴探险事故的措施。      

大断面锚杆锚索支护巷道强制放顶方法研究应用

本文分析了刨煤机工作面进、回风巷切顶线以里采空区顶板大面积不垮落对上隅角瓦斯治理造成的危害,并对几种强制放顶方法进行了研究,提出了实用、高效的放顶方法。