A New Tethered Balloon-Borne Payload for Fine-Scale Observations in the Cloudy Boundary Layer

A new scientific payload is introduced for fine-scale measurements of meteorological (wind vector, static air temperature, humidity, and air pressure) and microphysical (aerosol particles and cloud droplets) properties, suspended below a tethered balloon. The high resolution sensors and the tethered balloon are described. Measurements in a lifted fog layer from a first field campaign are presented.The detailed investigation of the fog/haze and the temperature inversion layer demonstrates the damping influence of the fog on temperature fluctuations, while thewind fluctuations are significantly decreased by theevolving temperature inversion, whichwas about 30 m above the fog layer.From spectral analysis the noise floors of the high-resolution sensors are determined to10^-6 kg m^-3 for the LWC (liquid water content) and 4 mK for the fast temperature sensor (UFT-B). The correlation betweentemperature and LWC structures in shallow haze layers is investigated. The release of latent heat and the corresponding warming in the haze of about 0.1 K could be quantified.     

Linear Time-Invariant Compensation of Cup Anemometer and Vane Inertia

We propose a method to compensate for the phase lag and the amplitudeattenuation in the cup anemometer signal. These two effects, caused by theinstrument's inertia, are the major flaws of the cup anemometer in additionto over-speeding. Since the instrument's response is invariant in wavenumber (not frequency) representation, we transform the signals to becompensated from the time domain to the spatial domain by using Taylor'shypothesis. In the spatial domain we apply a linear time-invariant filterto eliminate the phase lag and the amplitude attenuation. The proposedprocedure improves instrument performance down to spatial scales equal toor smaller than the distance constant of the anemometer. The method for cupanemometer compensation is presented in detail and later adapted for vanes.     

GPS观测数据的模拟研究

主要研究了地面基准站GPS观测值模拟情况,分析了GPS观测值模拟的意义、原理及流程、用到的数学模型等,并用编写的模拟软件模拟了武汉站的GPS观测值情况。结果表明,本模拟方法所模拟的GPS观测值和实测值很接近,能满足不同层次人员对GPS模拟观测值的需要。     

轨道交通整体床道测量

本文从地铁床道测量的意义出发,结合轨道交通八号线二期工程,介绍了轨道交通整体床道测量技术设计、作业方法、数据采集、成果分析,以及在作业过程中的注意事项.     

青藏高原形变对中国西部边界的影响

基于青藏高原GPS形变1991-1999年间的测量成果,通过对中尼(中国与尼泊尔)、中印(中国与印度)边界及中不(中国与不丹)边界附近GPS测站地壳水平运动速率的统计分析,运用平均速度法估算了近10a西部边境地区的形变面积。初步计算结果表明,青藏高原形变对我国西部边界存在影响,在1991-1999年之间西部边界的不均匀形变导致国土面积缩小0.37km2。     

星载GPS伪距测量数据质量分析

研究了星载GPS伪距测量精度评定方法以及粗差的探测方法,用自编的软件对CHAMP卫星和SAC-C卫星的星载GPS实测数据进行了详细的分析.结果表明:随着卫星高度角的不同,多路径效应与伪距测量噪声对星载GPS伪距测量精度的影响在0.5～3.0 m之间;CHAMP和SAC-C星载GPS观测数据中,伪距粗差观测值所占的比例分别达到1.2%和3.0%.     

Design of high precision horizontal control network for large-scale hydropower project

IntroductionThe design of high precision horizontal controlnetwork for large-scale hydropower project toconstruct control network and measure deforma-tion of monitoring network.It can be also divid-ed into horizontal control network and verticalcontrol ne…     

GPS第三频载波及民用码的信号质量分析

介绍了L5载波的特点,分析了L5载波对GPS测量的影响,用实测数据分析了三频载波的信噪比及各个民用码的噪声水平。     

Subarctic catchment water storage and carbon cycling – Leading the way for future studies using integrated datasets at Pallas,Finland

Subarctic ecohydrological processes are changing rapidly, but detailed and integrated ecohydrological investigations are not as widespread as necessary. We introduce an integrated research catchment site (Pallas) for atmosphere, ecosystems, and ecohydrology studies in subarctic conditions in Finland that can be used for a new set of comparative catchment investigations. The Pallas site provides unique observational data and high-intensity field measurement datasets over long periods. The infrastructure for atmosphere- to landscape-scale research in ecosystem processes in a subarctic landscape has recently been complemented with detailed ecohydrological measurements. We identify three dominant processes in subarctic ecohydrology: (a) strong seasonality drives ecohydrological regimes, (b) limited dynamic storage causes rapid stream response to water inputs (snowmelt and intensive storms), and (c) hydrological state of the system regulates catchment-scale dissolved carbon dynamics and greenhouse (GHG) fluxes. Surface water and groundwater interactions play an important role in regulating catchment-scale carbon balances and ecosystem respiration within subarctic peatlands, particularly their spatial variability in the landscape. Based on our observations from Pallas, we highlight key research gaps in subarctic ecohydrology and propose several ways forward. We also demonstrate that the Pallas catchment meets the need for sustaining and pushing the boundaries of critical long-term integrated ecohydrological research in high-latitude environments.