TY01和O02两种海面空气动力粗糙度方案的比较

本文采用美国国家浮标站(44008)2003年1～3月的资料，通过COARE算法(版本2．6b)，比较了O02和TY01这两种海面空气动力粗糙度长度的参数化方案。通过对摩擦速度、拖曳系数、海面粗糙度及风应力等物理因子的计算得出：在粗糙的海面上，TY01和O02两种参数化方案的计算结果是比较一致的。在考虑浪的信息方面，TY01和O02都是很好的参数化方案．它们都可以适用于不同的风速条件，适用于各种尺度的海洋及湖泊。但是这两种方案在处理幼波时存在不连续的缺点。并且，对于风速较小的光滑海面，尽管它们计算的结果较一致，但是仍然存在偏差。据此，本文的结果对于理论分析和数值计算如何正确使用上述两种海面空气动力粗糙度参数化方案，可提供必要的参考价值。     

资源三号02星激光测高精度分析与验证

资源三号02星搭载了我国首台对地观测的卫星激光测高试验性载荷,对该载荷的精度进行了理论分析,并采用多个区域进行了实际精度验证,同时对其在航天测绘中的应用进行了试验。资源三号02星激光测高仪在平坦地区(坡度≤2°)的理论高程精度为0.85m、平面精度14.2m。试验表明,资源三号02星激光测高仪获得的有效测高数据约占23.89%,检校场区域其高程精度为0.89m,平面精度为14.76m;华北地区高精度DSM地形数据验证其高程精度为1.09m,内陆渤海海面上的激光高程精度为0.47m。将激光足印点作为高程控制点时,在陕西渭南试验区能将资源三号02星立体影像无地面控制的高程精度从11.54m提高到1.90m。虽然资源三号02星激光测高仪为试验性载荷,但试验结果证实国产卫星激光测高数据能有效提高立体影像无地面控制的高程精度,在全球测图工程中具有推广应用价值,建议后续立体测图卫星搭载业务化应用的激光测高仪。     

资源卫星影像匹配粗差筛除算法设计与实现

针对影像匹配传统光束法模型的缺点,该文提出了一种基于不规则三角网(TIN)的局部面元粗差筛除算法。该算法从匹配点集出发,通过遍历TIN结点构建局部面元模型并计算坐标向量,然后根据向量的统计规则确定粗差及其限差,并完成匹配粗差筛除。基于ZY-1-02C卫星影像数据,对该算法进行了设计与实现。实验结果证明,该算法准确性、健壮性较好,具有良好的时间复杂度,可以避免传统算法的大量计算,提高遥感数字产品的自动化程度,也为误差处理理论提供了一个新方法。     

Hazard-consistent response spectra in the Region of Murcia (Southeast Spain): comparison to earthquake-resistant provisions

Hazard-consistent ground-motion characterisations of three representative sites located in the Region of Murcia (southeast Spain) are presented. This is the area where the last three damaging events in Spain occurred and there is a significant amount of data for comparing them with seismic hazard estimates and earthquake-resistant provisions. Results of a probabilistic seismic hazard analysis are used to derive uniform hazard spectra (UHS) for the 475-year return period, on rock and soil conditions. Hazard deaggregation shows that the largest hazard contributions are due to small, local events for short-period target motions and to moderate, more distant events for long-period target motions. For each target motion and site considered, the associated specific response spectra (SRS) are obtained. It is shown that the combination of two SRS, for short- and long-period ground motions respectively, provides a good approximation to the UHS at each site. The UHS are compared to design response spectra contained in current Spanish and European seismic codes for the 475-year return period. For the three sites analysed, only the Eurocode 8 (EC8) type 2 spectrum captures the basic shape of the UHS (and not the EC8 type 1, as could be expected a priori). An alternative response spectrum, anchored at short- and long-period accelerations, is tested, providing a close match to the UHS spectra at the three sites. Results underline the important contribution of the frequent, low-to-moderate earthquakes that characterize the seismicity of this area to seismic hazard (at the 475-year return period).     

中巴资源卫星HR与CCD图像融合方法探讨

中巴资源卫星（CBERS）多光谱CCD数据与全色HR数据空间分辨率相差较大,给图像融合带来一定困难。利用锐化、高通滤波（HPF）、Brovey变换、IHS变换、主成分变换、GS变换和小波变换等方法对CCD与HR数据进行融合试验。通过定性与定量分析,探讨了不同方法的融合效果。     

基于严格仿射变换模型的遥感影像RPC参数求解

提出了利用少量地面控制点,采用基于严格仿射变换模型求解遥感影像的RPC参数,并对CBERS-02B卫星HR相机遥感影像进行了试验,获得了一些有意义的结论。     

甲烷水合物CO2置换开采研究现状与展望

天然气水合物广泛存在于海底沉积物和大陆永冻区,是一种潜在的能源资源。CO2置换法开采天然气水合物,不仅可以从水合物藏中开采出天然气,还能够使空气中的CO2以水合物的形式长期埋存于地下。本文从可行性、微观机理及影响因素等方面,总结了甲烷水合物CO2置换法开采的研究现状,论述了目前研究中存在的问题及不足,并对以后的研究工作提出了一些展望和建议。     

Gas and Particle Products Distribution from the Reaction of β-Caryophyllene with Ozone

Gas and particulate reaction products from the ozonolysis of 02x7v278255207/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> -caryophyllene (I) in the presence of atmospheric air were investigated using a combination of gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). A Scanning Mobility Particle Sizer system (3936, TSI) and a Condensation Particle Counter (3025A, TSI) were used to study secondary organic aerosol formation. The nighttime oxidation was carried out in a large outdoor smog chamber (190 m³). A wide range of ring retaining and ring opening products in the gas and particle phase are reported over the course of the reaction. On average, measured gas and particle phase products accounted for 02x7v278255207/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0">64% of the reacted 02x7v278255207/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> -caryophyllene (I) carbon. Measurements show that a number of reaction products with low vapor pressure (e.g., 02x7v278255207/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-caryophyllone aldehyde (IV), 02x7v278255207/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-norcaryophyllone aldehyde (V), 02x7v278255207/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-caryophyllonic acid (VIII), 02x7v278255207/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-14-hydroxycaryophyllonic acid (XIV)) were found in the sample taken during the first 20 min of the reaction and may play an important role in the early formation of secondary organic aerosol. A detailed mechanism is proposed to account for most products observed in this investigation.     

Floodplain evolution in a small,tectonically active basin of northern California

Sediment cores were collected along ?oodplains in the Navarro River basin of coastal northern California to examine the controls on ?oodplain evolution in a tectonically active setting. Sedimentary strata were subsampled for organic content, bulk density, and grain size measurements. Organic samples were analysed for ¹⁴C age, which yielded net‐averaged sedimentation rates for all cores. Overbank deposition rates decreased at all study sites through time and declined in the downstream direction. The ability of intermediary‐order streams to store sediment in ?oodplains decreased the ability of highest‐order streams to record sediment‐pulse events. The effects of anthropogenic disturbance, primarily logging, on long‐term overbank deposition rates were minimal. Climatic variability, by affecting sediment loading in the channel network, is the principal control on ?oodplain evolution through the Holocene. A hypothetical model is proposed to explain overbank deposition rates in the Navarro basin, which may be extrapolated to the northern‐coastal California region during the late Pleistocene and Holocene. The complexities observed in sediment storage and routing in this study imply that caution should be made when extrapolating sediment‐yield measurements obtained at river mouths or coastal shelves to geomorphic events within small, tectonically active basins. Copyright © 2003 John Wiley & Sons, Ltd.     

A wind tunnel investigation of the influences of fetch length on the flux profile of a sand cloud blowing over a gravel surface

Wind tunnel tests were conducted to examine the fetch effect of a gravel surface on the ?ux pro?le of the sand cloud blowing over it using typical dune sand. The results suggest that the ?ux pro?le of blown sand over a gravel surface differs from that over a sandy surface and is characterized by a peak ?ux at a height above the surface while that over a sandy surface decreases exponentially with height. The ?ux pro?le of a sand cloud over a gravel surface can be expressed by a Gaussian peak function: q = a + b exp (?0·5((h ? c)/d)²), where q is the sand transport rate at height h, and a, b, c and d are regression coef?cients. The signi?cance of the coef?cients in the function could be de?ned in accordance with the fetch length of the gravel surface and wind velocity. Coef?cient c represents the peak ?ux height and increases with both wind velocity and fetch length, implying that the peak ?ux height is related to the bounce height of the particles in the blowing sand cloud. Coef?cient d shows a tendency to increase with both wind velocity and fetch length. The sum of a and b, representing the peak ?ux, increases with wind velocity but decreases with fetch length. The average saltation height derived from the cumulative percentage curve shows a tendency to increase with both the fetch length and wind velocity. For any fetch length of a gravel surface the sand transport equation is expressed as Q = C(1 ? U_t/U)(ρ/g)U³, where Q is the sand transport rate, U is the wind velocity, U_t is the threshold velocity measured at the same height as U, g is the gravitational acceleration, ρ is the air density, C is a proportionality coef?cient that decreases with the fetch length of the gravel surface. At a given wind velocity, the sand transport rate over a gravel surface is only 52–68 per cent of that over a sandy surface. The ?ux rate in true creep over a gravel surface increases with wind velocity but decreases with the fetch length, whereas the creep proportion (the ratio of creep ?ux to the sand transport rate) decreases with both the wind velocity and fetch length. Two‐variable (including fetch length and wind velocity) equations were developed to predict the peak ?ux height, average saltation height and transport rate. Copyright © 2004 John Wiley & Sons, Ltd.