共查询到19条相似文献，搜索用时 156 毫秒
1.
利用GPS网的观测资料,通过GAMIT软件求得5个测站对流层天顶总延迟,进而求出各测站对流层湿延迟;利用湿延迟与大气可降水量之间的转换关系得到各测站的大气可降水量。将所得GPS-PWV值与同时段探空资料所得的大气可降水量以及地表实际降水量进行对比分析,结果表明:GPS-PWV值与探空资料所得的PWV值比较相符;在降水前后,GPS-PWV有比较明显的变化,降水一般出现在GPS-PWV值迅速增加的4-6h内;实际降水量峰值与GPS-PWV增量大小也有较强的相关性。 相似文献
2.
针对水汽在大气中易于变化,高时空分辨率水汽资料的欠缺,造成强降雨短时临近的预报水平不高的问题,探讨分析了GPS水汽反演的精度。利用香港CORS数据,通过GAMIT软件解算获得各测站1 h大气可降水量时间序列,将其与探空数据获得的液态水含量（PWV）和实际降水量进行比较分析。结果表明,GPS／PWV与Radio／PWV在整体变化趋势上具有很好的一致性,其相关系数大于0.9;GPS／PWV与Radio／PWV精度相当,两者平均偏差小于1 mm,均方根误差小于3 mm;GPS反演的大气可降水量与实际降水量具有较好的对应关系,能够精确地监测到水汽变化的过程,可以用于水汽的监测和预报研究。 相似文献
3.
武汉地区GPS气象网试验研究 总被引：1，自引：1，他引：1
将精密星历与快速预报星历GPS可降水量进行比较，两者的相关系数为99．97％，均方根为0．048mm，得出可以利用快速预报星历进行GPS可降水量的准实时预报的结论。通过对武汉地区GPS测站的可降水量的比较，得出武汉地区水汽的分布状况。对一次降雨过程进行了GPS可降水量与实际降雨量的比较，表明GPS可降水量变化可反映和预报降雨发生的过程。 相似文献
4.
5.
利用GAMIT/GLOBK软件解算bjfs、shao、wuhn、twtf四个IGS站的数据,分别运用Hopfield、Saastamoinen、EGNOS模型,计算出测站shao的GPS大气可降水量,并结合气象数据,对三种不同对流层延迟模型在GPS探测大气可降水量中的精度进行了分析。结果表明,Saastamoinen模型的精度略高于Hopfield模型的精度,EGNOS模型精度好于Hopfield和Saastamoinen模型,但在气象条件变化剧烈时,其精度不如实测地面气象数据的Hopfield和Saastamoinen模型。 相似文献
6.
7.
基于MODIS与GPS的D-InSAR大气延迟改正量提取 总被引：1，自引：0，他引：1
受GPS站点密度的限制,利用GPS数据改正D-InSAR中大气延迟误差往往达不到很好的效果。为此,研究了GPS与MODIS联合实现大气延迟改正量提取方法,利用两期GPS观测数据及相应时间的MODIS数据分析GPS-PWV与MODIS-PWV的关系,进一步得到MODIS水汽的校正模型。经过GPS+MODIS算法改正后,大气延迟改正精度为3.618mm,满足形变测量的要求。实验结果表明:在大气状态变化缓慢时,利用GPS结合MODIS数据对D-InSAR大气延迟改正有一定的效果。 相似文献
8.
针对水汽含量在短时间内变化快、影响因素多,目前精确测定其含量仍是一个难点的现状,该文采用GAMIT软件,利用两次暴雨发生过程中香港地区6个连续运行参考站系统参考站数据,计算天顶对流层总延迟(ZTD)和大气可降水量(PWV),并与实际降雨量进行对比。研究结果表明,暴雨发生前后的1~2h或者更长时间内,天顶对流层延迟、大气可降水量和实际降水量一直保持着较好的对应关系,天顶对流层延迟和大气可降水量会出现骤增和骤降现象,而且天顶对流层延迟和可降水量的变化速度越快,说明大气环境越不稳定,降水概率也就越高。 相似文献
9.
成都地区地基GPS观测网遥感大气可降水量的初步试验 总被引：7，自引：0，他引：7
利用首个成都地区地基GPS观测网2004年7～9月30s间隔的测量数据，通过Bernese GPS SoftwareV4．2解算出30min间隔的天顶总延迟量，结合自动气象站获得的气象资料计算出30min间隔的GPS遥感的大气可降水量。与根据气象探空站探测资料算出的可降水量进行统计对比，确定出本次GPS遥感可降水量试验的精度为3．09mm，两种可降水量时间序列呈现高度的一致性。同时验证了计算对流层加权平均温度的Bevis经验公式在成都地区的适用性。 相似文献
10.
11.
12.
Three permanent GPS tracking stations in the trans Antarctic mountain deformation (TAMDEF) network were used to estimate precipitable water vapor (PWV) using measurement series covering the period of 2002–2005. TAMDEF is a National Science Foundation funded joint project between The Ohio State University and the United States Geological Survey. The TAMDEF sites with the longest GPS data spans considered in this research are Franklin Island East (FIE0), the International GNSS Service site McMurdo (MCM4), and Cape Roberts (ROB1). For the experiment, PWV was extracted from the ionosphere-free double-difference carrier phase observations, processed using the adjustment of GPS ephemerides (PAGES) software. The GPS data were processed with a 30 s sampling rate, 15-degree cutoff angle, and precise GPS orbits disseminated by IGS. The time-varying part of the zenith wet delay is estimated using the Marini mapping function, while the constant part is evaluated using the corresponding Marini tropospheric model. Previous studies using TAMDEF data for PWV estimation show that the Marini mapping function performs the best among the models offered by PAGES. The data reduction to compute the zenith wet delay follows the step piecewise linear strategy, which is subsequently transformed to PWV. The resulting GPS-based PWV is compared to the radiosonde observations and to values obtained from the Antarctic mesoscale prediction system (AMPS). This comparison revealed a consistent bias of 1.7 mm between the GPS solution and the radiosonde and AMPS reference values. 相似文献
13.
Seung-Woo Lee Jan Kouba Bob Schutz Do Hyeong Kim Young Jae Lee 《Journal of Geodesy》2013,87(10-12):923-934
This paper addresses real-time monitoring of the precipitable water vapor (PWV) from GNSS measurements and presents some results obtained from 6-month long GNSS PWV experiments using international and domestic GNSS networks. In the real-time GNSS PWV monitoring system a server/client structure is employed to facilitate formation of PWV networks and single-differenced GNSS measurements are utilized to mitigate errors in GNSS satellites’ orbits and clocks. An issue relating to baseline length between the server and clients is discussed in detail and as a result the PWV monitor is configured to perform in two modes depending on the baseline length. The server estimates sequentially the zenith wet delay of the individual stations, which is then converted into the PWV of the stations. We evaluate system performance by comparing the real-time PWV solution with reference solutions including meteorological measurements obtained with radiosondes and deferred-time precision GNSS PWV solutions. Results showed that the standard deviation of difference between the real-time PWV and the reference solutions ranged from 2.1 to 3.4 mm in PWV for a 6-month long comparison, which was improved to 1.4 to 2.9 mm by reducing comparison period to 20 days in winter. 相似文献
14.
Atmospheric modelling in GPS analysis and its effect on the estimated geodetic parameters 总被引：4，自引：2，他引：2
Permanently operating Global Positioning System (GPS) receivers are used today, for example, in precise positioning and determination
of atmospheric water vapour content. The GPS signals are delayed by various gases when traversing the atmosphere. The delay
due to water vapour, the wet delay, is difficult to model using ground surface data and is thus often estimated from the GPS
data. In order to obtain the most accurate results from the GPS processing, a modelling of the horizontal distribution of
the wet delay may be necessary. Through simulations, three such models are evaluated, one of which is developed in this paper.
In the first model the water vapour is assumed to be horizontally stratified, thus the wet delay can be described by only
one zenith parameter. The second model gives the wet delay with one zenith and two horizontal gradient parameters. The third
model uses the correlation between the wet-delay values in different directions. It is found that for large gradients and
strong turbulence the two latter models yield lower errors in the estimated vertical coordinate and wet-delay parameters.
For large gradients this improvement is up to 7 mm in the zenith wet-delay parameter, from 9 mm down to 2 and 4 mm for the
second and third models, respectively.
Received: 7 May 1998 / Accepted: 1 March 1999 相似文献
15.
16.
17.
18.
19.
大气水汽是对流层的重要组成部分之一,研究影响水汽的因素及精度具有重要意义。主要研究黄土高原地区大气可降水量（precipitable water vapor, PWV）的影响因素,并对其实际精度进行评估。首先,对ERA5（the fifth-generation atmospheric reanalysis data of ECMWF）的气压、气温数据和全球导航卫星系统（global navigation satellite system, GNSS）获取的天顶对流层延迟（zenith troposphere delay, ZTD）进行评定;然后,依据ERA5的气压、气温数据和GNSS的ZTD数据计算1 h分辨率的PWV,并利用误差传播理论推导PWV的理论误差; 最后, 与PWV实际计算误差进行对比,分析黄土高原地区PWV的精度。结果表明,基于GAMIT/GLOBK软件获得的GNSS ZTD与PANDA软件解算的GNSS ZTD差值的均方根（root mean square, RMS）和Bias分别为4.05 mm和-0.46 mm;ERA5气压和气温的平均RMS和Bias分别为3.36 hPa/1.97 K和-0.01 ?hPa/0.04 K;黄土高原地区PWV的理论误差为1.51 mm,实际误差为1.94 mm。计算得到的PWV精度较高,对水汽分布以及气候监测的研究具有重要意义。 相似文献