美国长期生态研究计划：背景、进展和前景

由美国国家科学基金会支持的长期生态研究计划于1980年启动，至今在理论研究、开发技术和服务社会方面都取得了举世瞩目的成就。该计划的发展分为 3个阶段，每一阶段大约为10年。在其发展的第一个阶段，是以研究站所代表的生态系统为研究对象，主要开展了生态系统的过程与格局方面的研究并系统采集和存贮了有关数据；在1990 -2000年的第二个发展阶段中，其研究工作的重点是开展跨站的网络研究和人类活动对生态系统的影响，以揭示生态系统的过程与格局在较大空间尺度上的特征；按照规划，美国长期生态研究计划的发展进入到第三个阶段后，其工作的重点是开展综合研究、进行生态预测和更好地为社会发展服务，同时加强生物多样性的研究和信息学的发展。     

胶东金矿集区硫和碳的循环与控矿作用

胶东金矿集区矿石中普遍含金属硫化物和碳酸盐矿物,某些矿床中还见有富含炭质的断裂破碎带.成矿溶液中含有大量的SO4^2-、HCO3^-、CO2和有机质等的含硫和含碳组分.矿石硫同位素组成明显富集重硫,结合胶东金矿主要成矿时期（早白垩世）特殊的地质背景、同期海水硫酸盐δ^34S平均值（约＋16‰）及现代海水沿NE-NNE向断裂倒灌情况,笔者认为,硫的主要来源与海水硫的大量补给有关.而根据碳、氧同位素组成特征分析,形成金矿床中方解石的物源有很大一部分来自前寒武系碳酸盐岩.浅表环境下成矿金属元素及硫、碳等物质在热液对流系统中的大规模循环是成矿的关键,SO4^2-与S2^-之间的临界转化是制约成矿金属元素活化-迁移-聚集的重要因素,而含碳组分（CO3^2-、HCO3^-、CO2和有机质）则有利于Au、Cu、Pb、Zn等元素的活化和迁移,含硫和含碳组分的循环及有关的物理化学反应之间有明显的关联性.     

SAR image despeckling with a multilayer perceptron neural network

Speckle noise in synthetic-aperture radar (SAR) images severely hinders remote sensing applications; therefore, the appropriate removal of speckle noise is crucial. This paper elaborates on the multilayer perceptron (MLP) neural-network model for SAR image despeckling by using a time series of SAR images. Unlike other filtering methods that use only a single radar intensity image to derive their parameters and filter that single image, this method can be trained using archived images over an area of interest to self-learn the intensity characteristics of image patches and then adaptively determine the weights and thresholds by using a neural network for image despeckling. Several hidden layers are designed for feedforward network training, and back-propagation stochastic gradient descent is adopted to reduce the error between the target output and neural-network output. The parameters in the network are automatically updated in the training process. The greatest advantage of MLP is that once the despeckling parameters are determined, they can be used to process not only new images in the same area but also images in completely different locations. Tests with images from TerraSAR-X in selected areas indicated that MLP shows satisfactory performance with respect to noise reduction and edge preservation. The overall image quality obtained using MLP was markedly higher than that obtained using numerous other filters. In comparison with other recently developed filters, this method yields a slightly higher image quality, and it demonstrates the powerful capabilities of computer learning using SAR images, which indicate the promising prospect of applying MLP to SAR image despeckling.     

特大型桥梁施工GPS高程控制网技术研究

探索了采用GPS技术建立桥梁施工高程控制网的难点及关键问题,分析了GPS跨河高程传递测量方法的技术要点,结合工程实例得出了一些结论和建议。     

Application of probabilistic neural network to design breakwater armor blocks

This study presents a probabilistic neural network (PNN) technique for predicting the stability number of armor blocks of breakwaters. The PNN is prepared using the experimental data of Van der Meer. The predicted stability numbers of the PNN are compared with those of previous studies, i.e. by an empirical formula and a previous neural network model. The agreement index between the measured and predicted stability numbers by PNN are better than those by the previous studies. The PNN offers a way to interpret the network's structure in the form of a probability density function and it is easy to implement. Therefore, it can be an effective tool for designers of rubble mound breakwaters.     

Matlab在矿区GPS网间接平差中的应用

针对矿区GPS网间接平差,首先,详细地分析了GPS网间接平差原理,按一定格式将GPS网中的观测数据编制成观测文件,其次,按观测文件的格式编制算法将数据读入并存储,然后用间接平差原理处理得到平差结果,最后绘制网形和误差椭圆并生成平差报告,为矿区控制网的建立和矿区生产管理提供了便利。实验验证了本文程序的实用性。     

GPS技术在金川露天矿边坡变形监测中的应用

本文结合金川露天矿边坡变形GPS监测研究,主要论述监测基点的选择,基点WGS-84坐标的确定,变形监测网的布设,GPS数据采集、处理和质量,坐标转换的实施等,给出反演推出的若干四等三角点及其它控制点的变形数据,这些数据和造成变形的物理成因符合得很好,最后概括出GPS技术应用于变形观测的若干优点。     

地面加密自动站资料同化和数值模拟

采用美国多部门研制的WRF模式及其四维变分同化系统,对2008年5月长江中下游地区一次强对流暴雨天气过程进行了数值模拟试验;并分别将质量控制前和质量控制后的华东地区地面加密自动站资料加入模式进行四维变分同化试验,与实况进行了对比。结果表明:模拟试验能较好的模拟此次降水过程;而采用四维变分同化经质量控制后的地面加密资料,模式效果最好,使降水预报在降水落区和降水量上都获得较为明显的改善;但质量控制前四维同化改善效果不明显。这说明地面资料的质量控制很重要,它能去伪存真。有效地利用地面加密自动站资料,能使资料的加入与模式更协调,从而得到了最佳的模拟效果。     

2015年济南地区雾霾天气过程大气物理量特征初步分析

文中对比分析了2015年29个雾、霾及雾霾混合天气过程中,章丘探空站L波段探空雷达和山东省气象局院内德国14通道地基微波辐射计观测的温度资料。对观测数据实施了质量控制,检验了精度和可信度,统计分析了宏观物理参量特征和日变化规律。针对雾、霾及雾霾天气过程各选取了一个个例进行分析,分析了大气中PM_2.5、PM₁₀、SO₂、NO₂、O₃、CO含量的变化情况,分析了相对湿度、液态水路径和综合水汽含量等的变化情况。结果表明:两种观测数据一致性较好,拟合优度高于0.97;贴地逆温层存在一定的季节变化,悬垂逆温层存在一定的差异,逆温层的变化、污染参量变化与雾霾的形成有密切关系;不同天气背景对大气物理参量有较大的影响,PM₁₀、AQI（空气质量指数）和CO均在相同时间段出现峰值,有明显的起伏;CO峰值雾霾天气中尤为明显,由早到晚随时间峰值逐渐增大,雾天和霾天峰值较小,雾霾天气明显大于雾天或霾天。     

Toward an improved global network for determination of tropospheric ozone climatology and trends

An examination of typical tropospheric ozone variability on daily, monthly, annual and interannual timescales and instrumental precision indicates that the current ozonesonde network is insufficient to detect a trend in tropospheric ozone of 1% per year at the 2 level even at stations with records a decade in length. From a trend prediction analysis we conclude that in order to detect a 1% per year trend in a decade or less it will be necessary to decrease the time between observations from its present value of 3–7 days to 1 day or less. The spatial distribution of the current ozonesonde stations is also inadequate for determining the global climatology of ozone. We present a quantitative theory taking into account photochemistry, surface deposition, and wind climatology to define the effectively sampled region for an observing station which, used in conjunction with the instrumental precision and the above prediction analysis, forms the basis for defining a suitable global network for determining regional and global ozone climatology and trends. At least a doubling of the present number of stations is necessary, and the oceans, most of Asia, Africa, and South America are areas where more stations are most needed. Differential absorption lidar ozone instruments have the potential for far more frequent measurements of ozone vertical profiles and hence potentially more accurate climatology and trend determinations than feasible with ozonesondes but may produce a (fair weather) biased data set above the cloud base. A strategy for cloudy regions in which either each station utilizes both lidars and sondes or each station is in fact a doublet comprised of a near-sea-level lidar and a proximal-mountain-top lidar could serve to minimize this bias.