沿海GNSS观测网中BERNESE软件处理方案比较

采用BERNESE软件"OBS-MAX"和"SHORTEST"两种独立基线生成方式和三种网平差基准定义方法制定出6种GNSS数据后处理方案,分别对中国沿海GNSS业务化观测网2009年与2011年的两批数据处理,并从外符合和内符合精度两个方面进行分析比较。结果表明:采用"OBS-MAX"独立基线生成方式得出的坐标精度更优,尤其是在原始观测数据质量不高的情况下;在网平差基准定义上,采用固定解得出的坐标内符合精度优于最小约束解,但其外符合精度较差。     

陆面模式中土壤冻融过程参数化研究进展

土壤冻融过程在寒区水文和气候系统中有着重要作用。陆面模式中土壤冻融过程的参数化对模式的设计和模拟结果有着关键作用。通过对广泛应用的Bucket，SIB，BATS，VIC，BEAS， LSM等几种主要的陆面模式中的冻融过程参数化方案进行了总结和比较。首先，详尽地描述了土壤冻融与气候变化的数值模拟研究，总结和评述了土壤冻融过程对气候变化的作用。其次，对几种主要的陆面过程模式在土壤水热参数化方案中对冻融过程的考虑及其特点进行了比较和讨论。还对冻结深度和冻结周期的预报模式进行了简介，最后对该领域当前面临的主要研究问题进行了探讨和阐述。     

APPLICATION OF BDA SCHEME IN TYPHOON TRACK PREDICTION

The MM5, which is the PSU/NCAR mesoscale nonhydrostatic limited-area model, and its adjoining modeling system are used in this paper. Taking T106 analysis data as background field the authors generate an optimal initial condition of a typhoon by using two bogus data assimilation schemes, and conduct some numerical simulating experiments. The results of No.9608 typhoon (Gloria) show that the optimal initial field have some dramatic improvements, such as inaccurate position of typhoon center, weaker typhoon circulation and incomplete inner structure of the typhoon, which are caused by shortage of data over the sea. Some improvements have been made in the track forecast. Through several comparing experiments, the initialization optimized by BDA scheme is found to be more reasonable than GFDL scheme and its typhoon track forecast is better.     

利用WRF对兰州冬季大气边界层的数值模拟

本文介绍了WRF中尺度模式的有关概况,分析了模式的物理结构,并利用WRF中尺度模式对河谷城市兰州冬季大气边界层的风场和温度场进行了数值模拟研究。模拟结果与观测事实基本一致,表明WRF模式具有良好的稳定性能。     

A Compact Explicit Difference Scheme of High Accuracy for Extended Boussinesq Equations

Presented here is a compact explicit difference scheme of high accuracy for solving the extended Boussinesq equations.For time discretization,a three-stage explicit Runge-Kutta method with TVD property is used at predicting stage,a cubic spline function is adopted at correcting stage,which made the time discretization accuracy up to fourth order;For spatial discretization,a three-point explicit compact difference scheme with arbitrary order accuracy is employed.The extended Boussinesq equations derived by Beji and Nadaoka are solved by the proposed scheme.The numerical results agree well with the experimental data.At the same time,the comparisons of the two numerical results between the present scheme and low accuracy difference method are made,which further show the necessity of using high accuracy scheme to solve the extended Boussinesq equations.As a valid sample,the wave propagation on the rectangular step is formulated by the present scheme,the modelled results are in better agreement with the experimental data than those of Kittitanasuan.     

用于ENSO预测的一种广义典型混合回归模式及其预报试验

提出一种基于主分量典型相关分析（ＰＣ－ＣＣＡ）的广义典型混合回归模式，用于建立ＮＩＮＯ海区ＳＳＴ预报方案．该模式引入ＥＥＯＦ、ＰＲＥＳＳ准则和集成预报等技术思想，在优选物理因子，确定最佳模式参数的基础上，对ＮＩＮＯ海区海温指数所作的超前１—４季度预报试验取得优良效果．试验表明，该模式方案性能稳定，其总体预报技术水平已达到美国ＮＯＡＡ／ＮＷＳ／ＮＣＥＰ／气候诊断公报（ＣＰＣ）所用同类模式水平．而本模式方案预报同类产品所需因子数远少于ＣＰＣ方法。这就有可能为建立我国的ＥＮＳＯ业务监测系统提供有益的基础。     

面向高年级本科生研究能力培养的资源环境遥感综合实验方案设计

近年来,随着研究生教育规模的逐年提升,高年级本科教育目标也随之发生一定变化,遥感专业教学中,有必要加强对学生研究能力的培养。本文以矿区资源环境遥感课程为例,以课程综合实验为切入点,结合课程特点提出了半开放式、可拓展的实验架构,探索了面向本科生研究能力培养需求的实验方案设计及教学实践工作,引导学生由被动接受向主动思考转变;由知识吸收向研究实践转变。向学生展示本专业科学研究的基本方法,为学生顺利进入社会工作岗位或转入更高学习阶段打好基础。     

Investigation of Uncertainties of Establishment Schemes in Dynamic Global Vegetation Models简

In Dynamic Global Vegetation Models （DGVMs）, the establishment of woody vegetation refers to flowering, fertiliza- tion, seed production, germination, and the growth of tree seedlings. It determines not only the population densities but also other important ecosystem structural variables. In current DGVMs, establishments of woody plant functional types （PFTs） are assumed to be either the same in the same grid cell, or largely stochastic. We investigated the uncertainties in the competition of establishment among coexisting woody PFTs from three aspects： the dependence of PFT establishments on vegetation states; background establishment; and relative establishment potentials of different PFTs. Sensitivity experi- ments showed that the dependence of establishment rate on the fractional coverage of a PFT favored the dominant PFT by increasing its share in establishment. While a small background establishment rate had little impact on equilibrium states of the ecosystem, it did change the timescale required for the establishment of alien species in pre-existing forest due to their disadvantage in seed competition during the early stage of invasion. Meanwhile, establishment purely fiom background （the scheme commonly used in current DGVMs） led to inconsistent behavior in response to the change in PFT specification （e.g., number of PFTs and their specification）. Furthermore, the results also indicated that trade-off between irtdividual growth and reproduction/colonization has significant influences on the competition of establishment. Hence, further development of es- tablishment parameterization in DGVMs is essential in reducing the uncertainties in simulations of both ecosystem structures and successions.     

Improvement of the semi-Lagrangian advection scheme in the GRAPES model: Theoretical analysis and idealized tests

ABSTRACT The Global/Regional Assimilation and PrEdiction System （GRAPES） is the newgeneration numerical weather predic- tion （NWP） system developed by the China Meteorological Administration. It is a fully compressible non-hydrostatical global/regional unified model that uses a traditional semi-Lagrangian advection scheme with cubic Lagrangian interpola tion （referred to as the SL_CL scheme）. The SL_CL scheme has been used in many operational NWP models, but there are still some deficiencies, such as the damping effects due to the interpolation and the relatively low accuracy. Based on Reich＇s semi-Lagrangian advection scheme （referred to as the R2007 scheme）, the Re_R2007 scheme that uses the low- and high-order B-spline function for interpolation at the departure point, is developed in this paper. One- and two-dimensional idealized tests in the rectangular coordinate system with uniform grid cells were conducted to compare the Re..R2007 scheme and the SL_CL scheme. The numerical results showed that： （1） the damping effects were remarkably reduced with the Re_R2007 scheme; and （2） the normalized errors of the Re_R2007 scheme were about 7.5 and 3 times smaller than those of the SL_CL scheme in one- and two-dimensional tests, respectively, indicating the higher accuracy of the Re..R2007 scheme. Furthermore, two solid-body rotation tests were conducted in the latitude-longitude spherical coordinate system with non uniform grid cells, which also verified the Re_R2007 scheme＇s advantages. Finally, in comparison with other global advection schemes, the Re_R2007 scheme was competitive in terms of accuracy and flow independence. An encouraging possibility for the application of the Re_R2007 scheme to the GRAPES model is provided.     

水源热泵井群布置方案对地下水流场影响分析

以某地下水源热泵系统工程为例,依据工程场地实际抽水-回灌试验数据,建立研究区地下水流数值模拟模型,分析该地区适宜的井群布置方案,并定量研究不同井群布置方案对地下水流场的影响范围与程度,为确定合理的井群布置方案提供技术支撑。研究表明：对于同一含水层回灌,随着抽水-回灌时间的延长,就有利于抽水-回灌能力及尽量减小对周边地下水开采的影响而言,抽水井、回灌井交叉布置,部分回灌井集中布置的方案较为合理。