Cross‐shore variations of near‐surface wind velocity and atmospheric turbulence at the land‐sea boundary during CASP

Abstract

Airborne measurements of mean wind velocity and turbulence in the atmospheric boundary layer under wintertime conditions of cold offshore advection suggest that at a height of 50 m the mean wind speed increases with offshore distance by roughly 20% over a horizontal scale of order 10 km. Similarly, the vertical gust velocity and turbulent kinetic energy decay on scales of order 3.5 km by factors of 1.5 and 3.2, respectively. The scale of cross‐shore variations in the vertical fluxes of heat and downwind momentum is also 10 km, and the momentum flux is found to be roughly constant to 300 m, whereas the heat flux decreases with height. The stability parameter, z/L (where z = 50 m and L is the local Monin‐Obukhov length), is generally small over land but may reach order one over the warm ocean. The magnitude and horizontal length scales associated with the offshore variations in wind speed and turbulence are reasonably consistent with model results for a simple roughness change, but a more sophisticated model is required to interpret the combined effects of surface roughness and heat flux contrasts between land and sea.

Comparisons between aircraft and profile‐adjusted surface measurements of wind speed indicate that Doppler biases of 1–2 m s^?1 in the aircraft data caused by surface motions must be accounted for. In addition, the wind direction measurements of the Minimet anemometer buoy deployed in CASP are found to be in error by 25 ± 5°, possibly due to a misalignment of the anemometer vane. The vertical fluxes of heat and momentum show reasonably good agreement with surface estimates based on the Minimet data.     

河南省旅游经济趋同与趋异研究

在分析河南省各地市旅游经济发展差异的基础上,用泰尔指数模型对河南省各地市旅游经济的趋同与趋异进行了研究,结果发现:2001—2007年河南省各地市旅游经济呈现出明显的趋同趋势;2008—2009年各地市旅游经济略显趋异;区内差异是导致河南省旅游经济差异的主要因素;中原城市群区内差异远远高于其他区域;四大区域之间也呈现出趋同趋势。据此,提出河南省整体旅游经济均衡快速发展建议:利用当前极化态势形成区域品牌,加快发达地区旅游产业转型升级,加大对旅游欠发达地区的政策扶持力度,落后地区发挥创意实现旅游快速发展。     

城市意象与旅游目的地意象研究中的趋同与分野

“意象”是近年来多学科研究追踪的热点命题之一。本文在重点文献回顾基础上,就城市意象和旅游目的地意象的研究发展脉络及方法进行了较为全面的回顾与分析,研究结果显示：二者的产生、发展与国际、国家的整体发展水平与人类的社会性需求存在密切联系,而这种社会性需求也决定了其研究的基本发展方向。就城市意象和旅游目的地意象研究本身来看,二者在研究的核心聚焦内容、研究的基本指向、研究方法与研究发展的外生动力上都基本趋于一致;在研究涉及群体与研究学科视角上存在明显的差别。同时,为了推进城市意象与旅游目的地意象研究的深化,提出了应关注“意象”的地方感研究与提升研究技术的具体建议。     

Estimation of ground heat flux and its impact on the surface energy budget for a semi-arid grassland

Three approaches, i.e., the harmonic analysis (HA) technique, the thermal diffusion equation and correction (TDEC) method, and the calorimetric method used to estimate ground heat flux, are evaluated by using observations from the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) in July, 2008. The calorimetric method, which involves soil heat flux measurement with an HFP01SC self-calibrating heat flux plate buried at a depth of 5 cm and heat storage in the soil between the plate and the surface, is here called the ITHP approach. The results show good linear relationships between the soil heat fluxes measured with the HFP01SC heat flux plate and those calculated with the HA technique and the TDEC method, respectively, at a depth of 5 cm. The soil heat fluxes calculated with the latter two methods well follow the phase measured with the HFP01SC heat flux plate. The magnitudes of the soil heat flux calculated with the HA technique and the TDEC method are close to each other, and they are about 2 percent and 6 percent larger than the measured soil heat flux, respectively, which mainly occur during the nighttime. Moreover, the ground heat fluxes calculated with the TDEC method and the HA technique are highly correlated with each other (R² = 0.97), and their difference is only about 1 percent. The TDEC-calculated ground heat flux also has a good linear relationship with the ITHP-calculated ground heat flux (R² = 0.99), but their difference is larger (about 9 percent). Furthermore, compared to the HFP01SC direct measurements at a depth of 5 cm, the ground heat flux calculated with the HA technique, the TDEC method, and the ITHP approach can improve the surface energy budget closure by about 6 percent, 7 percent, and 6 percent at SACOL site, respectively. Therefore, the contribution of ground heat flux to the surface energy budget is very important for the semi-arid grassland over the Loess Plateau in China. Using turbulent heat fluxes with common corrections, soil heat storage between the surface and the heat flux plate can improve the surface energy budget closure by about 6 to 7 percent, resulting in a closure of 82 to 83 percent at the SACOL site.     

东天山板块构造与金属矿产成矿规律

根据东天山及邻区地层、沉积建造、构造岩石组合、变形、变质、古生物分区、深部地壳结构、地球物理、地球化学特征，以康古尔塔格－黄山深断裂为界，划分了不同级别的构造单元和构造沉积相带。统计分析了２０２个金属矿床，重点研究了金、银、铜、镍、钼、铁等矿产空间分布与板块构造、碰撞带关系，划分出九个成矿带，三个成矿期，以海西中晚期最为显著。成矿与板缘构造活动带地质演化密切相关，与俯冲一碰撞带和韧性剪切带时空演化最为密切。构造分区控制的矿产成带性和构造演化形成的成矿集中期之间相互转化对该区金属矿产有重要控制作用。     

地幔柱理论研究概述

本文介绍了地幔柱理论研究的一系列进展，诸如地幔柱特征、动力学模式及其一系列地质效应；阐明了地幔柱构造与板块构造的关系。地幔柱理论涉及的是地幄深部物质垂直运动的机制，其研究对于进一步了解地球深部动力学机制有重大意义。     

Convergence of Liapunov series for Huygens–Roche Figures

According to the classical theory of equilibrium figures, surfaces of equal density, potential and pressure concur (let us call them isobars). Isobars can be represented by means of Liapunov power series in small parameter q, up to the first approximation coinciding with the centrifugal to gravitational force ratio at the equator. Liapunov has proved the existence of the universal convergence domain: the above mentioned series converge for all bodies (satisfying a natural condition that the density ρ decreases from the center to the surface) if |q| < q*. Using Liapunov’s algorithm and symbolic manipulation tools, we have found q*= 0.000370916. Evidently, the convergence radius q* may be much greater in common situations. To comfirm it it is reasonable to consider two limiting and one or two intermediate cases for the density behaviour: ρ is a constant, the Dirac’s δ-function, linear function of the distance from the center, etc. And indeed, in the previous paper we find a three orders of magnitude greater value for homogeneous figures. In the present paper we find that in the opposite case of Huygens-Roche figures (a point-mass surrounded by a weightless atmosphere) the convergence radius is unexpectedly large and coincides with the well-known biggest possible value q*= 0.541115598 for such a class of figures. To ascertain it we ought to use numerical calculations, so our main result is demonstrated by means of a computer assisted proof. This revised version was published online in July 2006 with corrections to the Cover Date.     

一种基于差分投影的汽车牌照自动识别方法

针对汽车牌照的特点,利用差分投影法对汽车图像进行处理,确定出牌照的准确位置并将其整体切割下来;然后利用差分投影法对牌照进行切分,切分出待识别的车牌字符;再利用模板匹配的方法对切分出的车牌字符进行识别.实践证明该方法对汽车牌照的自动识别非常有效.     

吉林深震的构造背景和区域地震能量的异常讨论

从吉林深震的形成与板块构造活动的关系入手，介绍了深震与吉林省区域构造活动背景的联系。利用测震学活动性指标，讨论了发震前后区域地震能量时空变化的特点，并结合对前兆资料的分析，得出了深震前后区域地震能量的累积与释放的特点。本文试图阐明异同，探讨机制，以期对地震活动规律的研究有所帮助。