一种利用AJAX BT技术提高WebGIS性能的方法

WebGIS的性能一直是困扰着WebGIS发展的一个瓶颈。本文在针对现有C/S和B/S模式不足,如初次登录时速度慢,页面常出现空白等问题的基础上,提出了将AJAX的部分数据动态传输技术和GIS改进型四叉树空间数据索引技术相结合的AJAX BT模式的WebGIS解决方案。该方案一方面减少空间数据传输量,并一定程度上实现了客户端与服务器端的负载平衡,另一方面使客户端的空间数据交互处理速度与空间数据所在整个空间区域的大小无关。因此,该方案在一定程度上达到了提高WebGIS性能的目的。     

A Polarized Radiative Transfer Model Based on Successive Order of Scattering

Based on Successive Order of Scattering approach, a full Vector Radiative Transfer model (SOSVRT) for vertically inhomogeneous plane-parallel media has been developed. To overcome computational burden of convergence, a simple approximation technique by truncating scattering orders with a geometry serial is used to reduce computational time. Analytical Fourier decomposition of phase matrix with three symmetry relationships and two mutual inverse operators has been implemented to further improve the computation efficiency. To improve the accuracy, a post-processing procedure is implemented to accurately interpolate the Stokes vector at arbitrary angles. Comparisons with the benchmarks for an atmosphere of randomly orientated oblate spheroids show excellent agreement for each stokes parameter (within 0.1%). SOSVRT has been tested for different atmospheric condition against RT3, which is based on doubling-adding method, the results approve that SOSVRT is accurate and much more efficient in vector radiative transfer modeling, especially for optical thin atmosphere, which is the most cases in polarized radiative transfer simulation. SOSVRT is written in fortran 90 and the code is freely accessible by contacting the author.     

外定标中海面参数对发射率影响研究

星载微波辐射计外定标的关键问题是通过辐射传输方程计算天线入瞳处亮温。根据辐射传输方程,海面成份对亮温的影响包括海面的微波辐射和对下行大气辐射的反射,其中的关键参数分别为海面发射率ep和海表面反射率R。文中对平静海面Fresnel反射率模式和粗糙海面反射率模式进行了研究分析,在此基础上着重研究了海面温度TS、海面盐度SS、海面风速W、以及观测角度θ等物理参数对海面发射率ep的影响,进而分析了这些物理参数的测量误差对亮温的计算精度的影响。     

Four-stream Radiative Transfer Parameterization Scheme in a Land Surface Process Model

Accurate estimates of albedos are required in climate modeling. Accurate and simple schemes for radiative transfer within canopy are required for these estimates, but severe limitations exist. This paper developed a four-stream solar radiative transfer model and coupled it with a land surface process model. The radiative model uses a four-stream approximation method as in the atmosphere to obtain analytic solutions of the basic equation of canopy radiative transfer. As an analytical model, the four-stream radiative transfer model can be easily applied efficiently to improve the parameterization of land surface radiation in climate models. Our four-stream solar radiative transfer model is based on a two-stream short wave radiative transfer model. It can simulate short wave solar radiative transfer within canopy according to the relevant theory in the atmosphere. Each parameter of the basic radiative transfer equation of canopy has special geometry and optical characters of leaves or canopy. The upward or downward radiative fluxes are related to the diffuse phase function, the G-function, leaf reflectivity and transmission, leaf area index, and the solar angle of the incident beam. The four-stream simulation is compared with that of the two-stream model. The four-stream model is proved successful through its consistent modeling of canopy albedo at any solar incident angle. In order to compare and find differences between the results predicted by the four- and two-stream models, a number of numerical experiments are performed through examining the effects of different leaf area indices, leaf angle distributions, optical properties of leaves, and ground surface conditions on the canopy albedo. Parallel experiments show that the canopy albedos predicted by the two models differ significantly when the leaf angle distribution is spherical and vertical. The results also show that the difference is particularly great for different incident solar beams. One additional experiment is carried out to evaluate the simulations of the BATS land surface model coupled with the two- and four-stream radiative transfer models. Station observations in 1998 are used for comparison. The results indicate that the simulation of BATS coupled with the four-stream model is the best because the surface absorbed solar radiation from the four-stream model is the closest to the observation.     

八项科技成果获2008年度新疆气象科技工作奖

为表彰2008年度在新疆气象科学技术工作中有较大贡献的科技人员,2008年12月24目新疆气象局科学技术委员会召开2008年度新疆气象科技工作奖评审会议。会议按照《新疆气象科学技术工作奖励办法》有关规定和要求,对申报新疆气象科技工作奖的13个项目和个人进行了评审。     

自动气象站数据采集传输报警系统开发

随着信息网络的快速发展,自动气象站已经普及、自动化观测也已经成为气象观测的必然趋势.但网络传输虽方便快捷,但也存在着不稳定性.如正点未采集生成数据文件或传输数据时网络中断而不能及时传送数据文件,不仅影响自动站的传输质量,且加大观测员的工作量.开发制作"自动气象站数据采集、传输报警系统"以缓解以上问题.     

精细化城镇天气预报的有效打包和传输

对新业务流程精细化城镇天气预报的文件命名、内容格式及时效进行介绍,并就提高新业务流程精细化城镇天气预报传输时效进行探讨.     

GPRS自动站数据传输的可行性分析

GPRS支持因特网上广泛应用的TCP/IP协议和X.25协议,作为专业数据的无线网络传输技术,被广泛的应用于各种无人自动气象站。本文分析了GPRS无线网络在气象台站资料传输中应用的特点,并通过实验在OSSMO2004地面气象测报业务软件中利用移动GPRS实现了自动气象站实时资料及天气报文的传输。     

沙尘传输路径上气溶胶浓度与干沉降通量的粒径分布特征

利用2002年春季中国北京、青岛和日本福冈3个地区的分级气溶胶浓度资料,结合改进的Wil-liams模型,分析了沙尘传输路径上空气动力学直径≤11μm气溶胶(PM11)浓度和干沉降通量的粒径分布特征,并估算了黄海海域春季PM11的干沉降通量及不同粒径气溶胶的贡献。结果表明:3个地区PM11浓度粒径分布在非沙尘时期呈双峰分布,两个峰值分别出现在细颗粒(<2.1μm)部分和粗颗粒(2.1～11μm)部分;沙尘时期,3个地区PM11浓度粒径分布均趋于单峰分布,峰值位于粗颗粒部分,并且越靠近沙尘源地,这种趋势越明显。较强沙尘天气时期,粗颗粒部分的浓度峰值粒径从沙尘源地附近到黄海西岸、东岸呈降低趋势,但在一般沙尘天气时期,这种现象并不明显。沙尘时期和非沙尘时期,3个地区粗颗粒的干沉降通量均随粒径增加而增大,细颗粒的干沉降通量随粒径的变化不明显。虽然沙尘时期粗颗粒沉降通量较非沙尘时期有明显增加,但粗颗粒对PM11干沉降通量的贡献与非沙尘时期相比,并没有明显的变化。较强沙尘天气时期,3个地区粗颗粒的干沉降通量明显高于一般沙尘天气时期;细颗粒的干沉降通量较一般沙尘天气时期略有增加。黄海海域春季沙尘时期PM11的干沉降通量约为31.70～58.59mg.m-2.d-1,非沙尘时期约为8.33～15.94mg.m-2.d-1。粗颗粒是黄海海域春季PM11干沉降通量的主要贡献者,约占PM11干沉降通量的94.2%以上。     

工业在线-电感耦合等离子体发射光谱法分析湿法冶炼硫酸锌溶液中铜镉钴铁

测定湿法冶炼硫酸锌溶液中的杂质元素,有助于优化电解液组成、减少能耗,精准投料,提高冶炼金属的纯度.对于杂质元素的测定,通常采用人工取样分析的方法,因杂质元素的含量较低,主元素锌和硫酸的含量较高,需要对样品进行稀释才能上机分析,难以实现自动化.为满足目前湿法冶炼的产业需求,本文建立了一种自动化工业在线过滤/稀释-电感耦合...