强度尺度分解方法在气候温度场检验中的应用

本文首次将Casati等提出的强度尺度分解方法应用到气候地表温度场的检验中,探讨此方法用于评估气候模拟场误差的详细空间信息的适用性。以新一代气候系统模式模拟的月平均地表温度为例,传统的统计分析方法（较为常用的是空间相关系数和均方根误差、EOF分析等）不能完全反映模拟场误差的空间信息;强度尺度分解方法可计算不同阈值和空间尺度上的均方误差和模拟技巧,评估对应的模拟能力,定量给出模拟场主要误差的空间信息（误差范围即温度阈值及对应的空间尺度）,例如,亚洲东部地区1月单年及多年平均的模拟场在230 K阈值1600 km模拟技巧非常低。本研究表明强度尺度分解方法适用于气候温度场的检验评估,能定量给出误差的空间信息。     

南海海岛自动气象站防护应用技术探索

立足海南及南海的自然条件,结合海岛自动气象站在南海高温、高湿、高盐雾、强辐射、强风等恶劣气候环境下使用情况,通过对历年来海岛自动气象站故障及失效模式的统计和分析,总结分析故障原因。根据设备维护人员多年气象设备保障工作积累总结的经验,从海岛自动气象站结构和防护要求出发,集成应用市场上优质材料、先进工艺和多种成熟、关键设备防护技术,形成一些气象设备防护的有效方法措施,以提高海岛自动气象站对海洋环境的适应性和性能,延长设备使用寿命。     

一种数字地图新产品--PDF地图

针对目前数字地图产品的使用现状和需求,提出了PDF地图产品。首先给出了PDF地图的定义与特征,其次详细描述了PDF地图的数据模型及生成方法,最后总结了PDF地图的两种基本应用模式,并验证了其可行性和有效性。     

薄板样条函数支持下的等深线追踪算法研究

基于薄板样条函数的拟合曲面能很好地根据水深点数据模拟水下地形,通过建立一定密度的规则格网可以十分精细地追踪等深线。因薄板样条曲面是光滑的,故生成的等深线具有一定的平滑性。本文首先论述了薄板样条曲面的解算步骤,然后研究了在该曲面上构建规则格网模型和追踪等深线的算法,最后以南方CASS作为实现平台,根据实际数据生成的等深线效果证明了本文提出的算法是可行有效的,能有效地避免曲线拟合过程中产生的凸起或陡变现象。     

地理国情普查外业调绘核查系统实现

针对传统的基于纸质地图的外业调绘核查工作具有操作复杂、采集数据不精确、作业流程不规范等缺点,该文设计开发了基于iPad的地理国情普查外业调绘核查系统。在内业高精度遥感影像判读的基础上,采用全数字化的外业调绘核查技术,进行地理国情要素移动式、网络化外业调查和验证,快速采集和编辑调查数据,为外业工作提供了一套完整的解决方案。该系统在青岛市崂山区和城阳区的试点中已经得到广泛的应用,较好地验证了移动GIS技术用于外业信息采集的可行性。     

Generating GPS satellite fractional cycle bias for ambiguity-fixed precise point positioning

With the development of precise point positioning (PPP), the School of Geodesy and Geomatics (SGG) at Wuhan University is now routinely producing GPS satellite fractional cycle bias (FCB) products with open access for worldwide PPP users to conduct ambiguity-fixed PPP solution. We provide a brief theoretical background of PPP and present the strategies and models to compute the FCB products. The practical realization of the two-step (wide-lane and narrow-lane) FCB estimation scheme is described in detail. With GPS measurements taken in various situations, i.e., static, dynamic, and on low earth orbit (LEO) satellites, the quality of FCB estimation and the effectiveness of PPP ambiguity resolution (AR) are evaluated. The comparison with CNES FCBs indicated that our FCBs had a good consistency with the CNES ones. For wide-lane FCB, almost all the differences of the two products were within ±0.05 cycles. For narrow-lane FCB, 87.8 % of the differences were located between ±0.05 cycles, and 97.4 % of them were located between ±0.075 cycles. The experimental results showed that, compared with conventional ambiguity-float PPP, the averaged position RMS of static PPP can be improved from (3.6, 1.4, 3.6) to (2.0, 1.0, 2.7) centimeters for ambiguity-fixed PPP. The average accuracy improvement in the east, north, and up components reached 44.4, 28.6, and 25.0 %, respectively. A kinematic, ambiguity-fixed PPP test with observation of 80 min achieved a position accuracy of better than 5 cm at the one-sigma level in all three coordinate components. Compared with the results of ambiguity-float, kinematic PPP, the positioning biases of ambiguity-fixed PPP were improved by about 78.2, 20.8, and 65.1 % in east, north, and up. The RMS of LEO PPP test was improved by about 23.0, 37.0, and 43.0 % for GRACE-A and GRACE-B in radial, tangential, and normal directions when AR was applied to the same data set. These results demonstrated that the SGG FCB products can be produced with high quality for users anywhere around the world to carry out ambiguity-fixed PPP solutions.     

思维导图方法的教学实践

思维导图在国内外已有多项研究证明思维导图在促进学生创新思维发展上有作用。在测绘类学科的高校教学中引入思维导图这种学习和工作方法,用在测绘本科教学改革中的讲座责任制授课模式上,通过在测绘本科教学方法改革的需求分析、应用实践和学生调查统计,得出结论:思维导图用于测绘类高校教学中,有利于提高学生创新思辨和自主学习能力,有助于达到以"能力"为核心的测绘专业人才培养目标。