共查询到19条相似文献，搜索用时 171 毫秒
1.
利用地面气象观测资料确定对流层加权平均温度 总被引：13，自引：0，他引：13
地基ＧＰＳ气象学的核心思想是通过垂直方向上ＧＰＳ信号的湿分量延时确定出可降水分,而这两个物理量之间的转换必须使用对流层加权平均温度。本首先讨论了上述转换估计中加权平均温度的几种遏近方式及其容许误差,然后利用香港地区的地面和高空气象资料,采用逐步回归分析方法,建立了适合香港地区的对流层加权平均温度计算公式,通过数据分析表明,这个公式有效地消除了在香港地区使用Ｂｅｖｉｓ经验公式引起的系统误差,较好地 相似文献
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利用地面气象观测资料确定对流层加权平均温度 总被引：2，自引：0，他引：2
地基GPS气象学的核心思想是通过垂直方向上GPS信号的湿分量延时确定出可降水分 ,而这两个物理量之间的转换必须使用对流层加权平均温度。本文首先讨论了上述转换估计中加权平均温度的几种逼近方式及其容许误差 ,然后利用香港地区的地面和高空气象资料 ,采用逐步回归分析方法 ,建立了适合香港地区的对流层加权平均温度计算公式 ,通过数据分析表明 ,这个公式有效地消除了在香港地区使用Bevis经验公式引起的系统误差 ,较好地满足了地基GPS气象应用中实时性和高精度的要求。本研究也充分表明 ,在地基GPS气象研究中 ,应该利用本地区的气象资料来确定适合本地区的估计对流层加权平均温度的经验公式。 相似文献
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《武汉大学学报(信息科学版)》2010,(6)
利用IGS提供的精密星历及精密钟差,分别采用卡尔曼滤波法、双差法对天顶对流层延迟进行估计,并与IGS提供的测站天顶延迟进行对比。根据所解算的天顶对流层延迟,利用经验模型求解天顶干延迟,最后分离出天顶湿延迟,进行大气可降水分的求解。 相似文献
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大气可降水份的估计是地基GPS气象学的一个主要研究方向。本文介绍了大气折射对GPS测量的影响,简介了两种常用的天顶干延迟分量模型——Saastamoinen模型和Hopfield模型和各种模型的特点。通过对北京、乌鲁木齐、拉萨3个IGS站的气象数据对这两个的天顶延迟干分量模型进行了分析总结。 相似文献
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InSAR大气延迟误差分析 总被引：3，自引：1，他引：2
分析了大气延迟的各分量（干延迟、湿延迟、液态水延迟和电离层延迟）对InSAR观测的影响。结合InSAR／DInSAR的数学模型，推导了对流层延迟对重轨干涉测量模式影响的双差模型、对三轨法和四轨法DInSAR对流层延迟的三差模型。并基于此，依据误差传播定律推导了对流层延迟误差对InSAR产品精度影响的公式。 相似文献
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GPS技术在气象学中的应用 总被引：9，自引：0，他引：9
ＧＰＳ技术的成熟使其成为对地观测的一种强有力的手段。ＧＰＳ技术在大气观测和全球气候变化监测中应用的可能性使得ＧＰＳ气象学（ＧＰＳ／ＭＥＴ）成为一个崭新的极有潜力的研究方向。本文对ＧＰＳ气象学及其分类作简单介绍之后,着重地阐述了ＧＰＳ气象学的基本原理和ＧＰＳ气象学的广阔应用领域。 相似文献
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无气象要素的GPS对流层延迟推算可降水量的研究 总被引：2，自引：0，他引：2
本文针对武汉地区GPS气象网资料,进行了GPS对流层延迟直接推算可降水量的研究。在武汉东湖站GPS对流层延迟与无线电探空可降水量的比较中,两者具有很好的相关性,相关系数达到了0.93;推导了对流层延迟直接推算可降水量的模型,对模型结果进行了检验,在武汉东湖站的对流层延迟转换的可降水量与无线电探空可降水量的比较中,均方根为7.8mm,相关性为0.91,这说明了在没有气象数据的地区对流层延迟直接推算的可降水量可以作为气象短期预报的参考。 相似文献
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Spatial and temporal resolution of water vapor content is useful in improving the accuracy of short-term weather prediction. Dense and continuously tracking regional GPS arrays will play an important role in remote sensing atmospheric water vapor content. In this study, a piecewise linear solution method was proposed to estimate the precipitable water vapor (PWV) content from ground-based GPS observations in Hong Kong. To evaluate the solution accuracy of the water vapor content sensed by GPS, the upper air sounding data (radiosonde) that are collected locally was used to calculate the precipitable water vapor during the same period. One-month results of PWV from both ground-based GPS sensing technique and radiosonde method are in agreement within 1–2 mm. This encouraging result will motivate the GPS meteorology application based on the establishment of a dense GPS array in Hong Kong. 相似文献
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Spatial and temporal resolution of water vapor content is useful in improving the accuracy of short-term weather prediction.Dense and continuously tracking regional GPS arrays will play an important role in remote sensing atmospheric water vapor content.In this study,a piecewise linear solution method was proposed to estimate the precipitable water vapor (PWV) content from ground-based GPS observations in Hong Kong.To evaluate the solution accuracy of the water vapor content sensed by GPS,the upper air sounding data (radiosonde) that are collected locally was used to calculate the precipitable water vapor during the same period.One-month results of PWV from both ground-based GPS sensing technique and radiosonde method are in agreement within 1～2 mm.This encouraging result will motivate the GPS meteorology application based on the establishment of a dense GPS array in Hong Kong. 相似文献
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Pierre Bosser Olivier Bock Christian Thom Jacques Pelon Pascal Willis 《Journal of Geodesy》2010,84(4):251-265
This paper investigates the impact of rapid small-scale water vapor fluctuations on GPS height determination. Water vapor
measurements from a Raman lidar are used for documenting the water vapor heterogeneities and correcting GPS signal propagation
delays in clear sky conditions. We use data from four short observing sessions (6 h) during the VAPIC experiment (15 May–15
June 2004). The retrieval of wet delays from our Raman lidar is shown to agree well with radiosonde retrievals (bias and standard
deviation (SD) were smaller than 1 and 2.8 mm, respectively) and microwave radiometers (from two different instruments, bias
was 6.0/−6.6 mm and SD 1.3/3.8 mm). A standard GPS data analysis is shown to fail in accurately reproducing fast zenith wet
delay (ZWD) variations. The ZWD estimates could be improved when mean post-fit phase residuals were removed. Several methodologies
for integrating zenith lidar observations into the GPS data processing are also presented. The final method consists in using
lidar wet delays for correcting a priori the GPS phase observations and estimating a scale factor for the lidar wet delays
jointly with the GPS station position. The estimation of this scale factor allows correcting for a mis-calibration in the
lidar data and provides in the same way an estimate of the Raman lidar instrument constant. The agreement of this constant
with an independent determination using radiosonde data is at the level of 1–4%. The lidar wet delays were derived by ray-tracing
from zenith pointing measurements: further improvement in GPS positioning is expected from slant path lidar measurements that
would properly account for water vapor anisotropy. 相似文献
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Numerical simulation of troposphere-induced errors in GPS-derived geodetic time series over Japan 总被引：2，自引：2，他引：0
Troposphere-induced errors in GPS-derived geodetic time series, namely, height and zenith total delays (ZTDs), over Japan
are quantitatively evaluated through the analyses of simulated GPS data using realistic cumulative tropospheric delays and
observed GPS data. The numerical simulations show that the use of a priori zenith hydrostatic delays (ZHDs) derived from the
European Centre for Medium-Range Weather Forecasts (ECMWF) numerical weather model data and gridded Vienna mapping function
1 (gridded VMF1) results in smaller spurious annual height errors and height repeatabilities (0.45 and 2.55 mm on average,
respectively) as compared to those derived from the global pressure and temperature (GPT) model and global mapping function
(GMF) (1.08 and 3.22 mm on average, respectively). On the other hand, the use of a priori ZHDs derived from the GPT and GMF
would be sufficient for applications involving ZTDs, given the current discrepancies between GPS-derived ZTDs and those derived
from numerical weather models. The numerical simulations reveal that the use of mapping functions constructed with fine-scale
numerical weather models will potentially improve height repeatabilities as compared to the gridded VMF1 (2.09 mm against
2.55 mm on average). However, they do not presently outperform the gridded VMF1 with the observed GPS data (6.52 mm against
6.50 mm on average). Finally, the commonly observed colored components in GPS-derived height time series are not primarily
the result of troposphere-induced errors, since they become white in numerical simulations with the proper choice of a priori
ZHDs and mapping functions. 相似文献
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LIU Yanxiong CHEN Yongqi LIU Jingnan 《地球空间信息科学学报》2001,4(1):14-18
1 ＩｎｔｒｏｄｕｃｔｉｏｎＩｎ ｇｒｏｕｎｄ＿ｂａｓｅｄＧＰＳＭｅｔｅｏｒｏｌｏｇｙ ,ｔｈｅ ｐｒｅｃｉｐ ｉｔａｂｌｅｗａｔｅｒｖａｐｏｒｉｓｃｏｎｖｅｒｔｅｄｆｒｏｍｔｈｅｗｅｔｚｅｎｉｔｈｄｅｌａｙｏｆｔｈｅＧＰＳｓｉｇｎａｌ.Ｑｕａｌｉｔａｔｉｖｅｌｙ ,ｔｈｅＰｒｅｃｉｐ ｉｔａｂｌｅＷａｔｅｒＶａｐｏｒ (ＰＷＶ)ｃａｎｂｅｒｅｌａｔｅｄｔｏｔｈｅＷｅｔＺｅｎｉｔｈＤｅｌａｙ (ＷＺＤ)ｂｙＰＷＶ =Ｆ·ＷＺＤＦ =1 0 6ρｖ·Ｒｖ· ｋ3Ｔｍ +ｋ2( 1 )ｗｈｅｒｅｔｈｅｍａｐｐｉｎｇｓｃａｌｅｆａｃｔ… 相似文献
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The weighted mean tropospheric temperature is a critical parameter in the conversion of wet zenith delay to precipitable water vapor in GPS Meteorology. This parameter can not be calculated from the radiosonde data in real time through the conventional methods. In this study, we first discuss the admissible error of weighted mean temperature to enable the accuracy of the conversion better than 1 mm, then summarize the performance of some of the existing methods. An empirical formula is established that satisfies the real-time requirement in GPS meteorology using Sequential Regression Analysis method. It is shown that this real-time formula as compared with other empirical methods is more accurate for local applications. 相似文献
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The estimates of total zenith delay are derived using Bernese GPS Software V4. 2 based on GPS data every 30 s from the first measurement experiment of a ground-based GPS network in Chengdu Plain of Southwest China during the period from July to September 2004. Then the estimates of 0.5 hourly precipitable water vapor (PWV) derived from global positioning system (GPS) are obtained using meteorological data from automatic weather stations (AWS). The comparison of PWV derived from GPS and those from radiosonde observations is given for the Chengdu station, with RMS (root mean square) differences of 3.09m. The consistency of precipitable water vapor derived from GPS to those from radiosonde is good. It is concluded that Bevis’ empirical formula for estimating the weighted atmospheric mean temperature can be applicable in Chengdu area because the relationship of GPS PWV with Bevis’ formula and GPS PWV with radiosonde method shows a high correlation. The result of this GPS measurement experiment is helpful both for accumulating the study of precipitable water vapor derived from GPS in Chengdu areas located at the eastern side of the Tibetan Plateau and for studying spatial-temporal variations of regional atmospheric water vapor through many disciplines cooperatively. 相似文献
19.
Kristine M. Larson Eric E. Small Ethan Gutmann Andria Bilich Penina Axelrad John Braun 《GPS Solutions》2008,12(3):173-177
Measurements of soil moisture are important for studies of climate and weather forecasting, flood prediction, and aquifer
recharge studies. Although soil moisture measurement networks exist, most are sparsely distributed and lack standardized instrumentation.
Measurements of soil moisture from satellites have extremely large spatial footprints (40–60 km). A methodology is described
here that uses existing networks of continuously-operating GPS receivers to measure soil moisture fluctuations. In this technique,
incoming signals are reflected off and attenuated by the ground before reception by the GPS receiver. These multipath reflections
directly affect signal-to-noise ratio (SNR) data routinely collected by GPS receivers, creating amplitude variations that
are a function of ground reflectivity and therefore soil moisture content. After describing this technique, multipath reflection
amplitudes at a GPS site in Tashkent, Uzbekistan are compared to estimates of soil moisture from the Noah land surface model.
Although the GPS multipath amplitudes and the land surface model are uncalibrated, over the 70-day period studied, they both
rise sharply following each rainfall event and slowly decrease over a period of ∼10 days. 相似文献