Subsurface flow measurements using passive flux meters in variably-saturated cold-regions landscapes

To date, passive flux meters have predominantly been applied in temperate environments for tracking the movement of contaminants in groundwater. This study applies these instruments to reduce uncertainty in (typically instantaneous) flux measurements made in a low-gradient, wetland dominated, discontinuous permafrost environment. This method supports improved estimation of unsaturated and over-winter subsurface flows which are very difficult to quantify using hydraulic gradient-based approaches. Improved subsurface flow estimates can play a key role in understanding the water budget of this landscape.     

SII型海洋重力仪稳定平台颤动故障与排除方法

S型海洋重力仪是目前海洋重力测量中较为常用的一种仪器，其产品性能也逐步得到提高。介绍了进行全自动化控制升级后，最新引进的SⅡ型海洋重力仪使用中出现的稳定平台颤动故障现象及排除办法。     

Observations of the Labrador Sea eddy field

This paper is an observational study of small-scale coherent eddies in the Labrador Sea, a region of dense water formation thought to be of considerable importance to the North Atlantic overturning circulation. Numerical studies of deep convection emphasize coherent eddies as a mechanism for the lateral transport of heat, yet their small size has hindered observational progress. A large part of this paper is therefore devoted to developing new methods for identifying and describing coherent eddies in two observational platforms, current meter moorings and satellite altimetry. Details of the current and water mass structure of individual eddy events, as they are swept past by an advecting flow, can then be extracted from the mooring data. A transition is seen during mid-1997, with long-lived boundary current eddies dominating the central Labrador Sea year-round after this time, and convectively formed eddies similar to those seen in deep convection modeling studies apparent prior to this time. The TOPEX / Poseidon altimeter covers the Labrador Sea with a loose “net” of observations, through which coherent eddies can seem to appear and disappear. By concentrating on locating and describing anomalous events in individual altimeter tracks, a portrait of the spatial and temporal variability of the underlying eddy field can be constructed. The altimeter results reveal an annual “pulsation” of energy and of coherent eddies originating during the late fall at a particular location in the boundary current, pinpointing the time and place of the boundary current-type eddy formation. The interannual variability seen at the mooring is reproduced, but the mooring site is found to be within a localized region of greatly enhanced eddy activity. Notably lacking in both the annual cycle and interannual variability is a clear relationship between the eddies or eddy energy and the intensity of wintertime cooling. These eddy observations, as well as hydrographic evidence, suggest an active role for boundary current dynamics in shaping the energetics and water mass properties of the interior region.     

AutoCAD技术在道路工程施工测量中的应用

在道路建设中,通常分为几个标段同时施工,每个标段里一般包括路基及各种构造物,因此,施工测量任务十分繁重,由于全站仪在工程测量中的普遍应用,其极坐标放样功能使测量工作中出现错误主要为坐标计算错误,特别是具有记忆功能的全站仪,可以事先输入坐标,复核后再到现场放样。所以测量的主要工作就是根据施工图纸计算其各个部位的坐标,而如何快速、准确地计算坐标是关键所在。应用AutoCAD技术进行坐标定位计算,则可以做到事半功倍,并能取得良好的施工效果。     

紫色土水分特征曲线室内测定方法的对比

为探寻全吸力范围内土壤水分特征曲线的可靠测定方法,采用沙箱排水法、Hyprop仪蒸发法、压力膜仪排水法和露点水势仪蒸发法分吸力段测定盐亭紫色土耕地表层2~7 cm和亚表层7~12 cm土壤的水分特征曲线,对比测定结果的方法间差异,并分析其原因。结果表明:对于表层和亚表层土壤,低吸力段(h >-100 cm)水分特征曲线的沙箱法和Hyprop仪法的均方根误差E_RMS (θ)均较小,在0.026~0.082 cm3/cm3范围内,确定系数R2均大于0.962,说明这两种方法测定结果之间差异不大。高吸力段(h <-330 cm)的压力膜仪法与露点仪法测定结果之间的差异较大,E_RMS (θ)为0.062~0.097 cm3/cm3,R2较低,为0.775~0.952。因此,全吸力范围内水分特征曲线测定方法的选择与组合应考虑土壤孔径分布特征和研究目的。     

南极中山站全天信息采集系统

南极高原拥有独特的天文观测优势,为了对南极中山站夜天文观测条件进行实测研究,中国科学院云南天文台专门研制了一套具有耐低温、自动除雪除霜等适应南极气候特征的全自动全天信息采集系统,该系统可以提供实时的全天云量、天光背景和全天图像,并将信息推送到网页实时显示。介绍了系统的研制及为适应南极气候进行的耐低温实验,统计分析了中山站2016~2017年的全天信息数据,结果显示,中山站2016和2017年的可观测时间为772.21 h和437.38 h,可观测夜数为93 d和51 d,天光背景最大真实值为22.05 Mag/arcsec 2,年平均气温为-10.6℃,最高气温19.1℃,最低气温为-44℃,2016年平均相对湿度为55.2%。     

拖缆式验潮仪结构设计和实现

以2003年完成定型生产并投入使用的新型号拖缆式验潮仪为例,简要介绍了设备的设计思想、实现方法和新特技术的应用,涉及到嵌入式计算机的选型、智能探头、汉字和图形人机界面、多路串行通讯、潮汐数据实时获取和系统在应用升级等设计细节。     

DNQ3型能见度仪故障分析及校准方法研究

为有效提高国家地面气象观测站能见度仪观测数据准确性和设备运行稳定性,对能见度仪开展日常维护、核查校准、数据质控和故障修复等工作显得尤为重要。该文通过对DNQ3型前向散射能见度仪硬件结构和基本工作原理的介绍,以及对一些典型故障进行分析,总结出能见度仪的检测维修流程,归纳了对应的故障解决措施,凝练出该型能见度仪的核查校准和疑误数据质控方法,为一线业务人员开展能见度仪常规维护、故障排查、运行监控等提供借鉴。     

西太平洋台风对上海地区钻孔应变的低频扰动特征分析

基于上海佘山台四分量钻孔应变仪在6次西太平洋台风期间的观测记录,利用小波分解、优势振动方向等处理方法提取出台风所激发的显著低频扰动信号,并详细分析扰动信号在时频域及空间域的表现特性.结果显示:在低频区间,台风激发的扰动信号优势周期为2～4 min,信号能量随台风进程而变化,并主要与台风量级、台风中心的位置(海上或陆域)...     

SII型海洋重力仪稳定平台倒台故障分析与处理

SⅡ型海洋重力仪凭借其动态测量精度高、系统可靠性强等优点已日益成为海洋调查中重力测量的重要仪器之一。从SⅡ型海洋重力仪在使用中出现的稳定平台倒台故障着手,分析了平台倒台故障的原因以及处理方法,并对仪器使用中的注意事项以及改进建议作了介绍。