共查询到18条相似文献，搜索用时 125 毫秒
1.
雾灵山山基掩星观测反演误差分析 总被引：1，自引：0，他引：1
运用山基GPS掩星探测技术对2005年8月河北雾灵山山基GPS掩星观测试验数据进行了处理,获得了接收机高度以下的大气折射率廓线;分析了掩星反演结果的内部符合情况,并利用同时进行的联合探空观测数据,将探空结果与掩星反演结果进行了比对分析.分析结果表明,山基GPS掩星反演大气折射率的内部符合精度优于1%,与常规探空结果的平均偏差为5.9%.反演结果偏小,标准偏差为5.6%. 相似文献
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以高精度和高垂直分辨率探测大气区间对流层顶—平流层底UTLS（Upper Troposphere/Lower Stratosphere,5—35 km）的温度和水汽廓线是提高大气条件变化监测水平的关键,而利用激光掩星方法同时探测温度和水汽则是对现有探测技术的重要补充。本文研究了激光掩星协同探测和反演温度和水汽分子数密度的方法,其中重点研究了双吸收波长近红外激光反演温度的方法,具体为从近红外波段氧气吸收光谱中,选择2个不同跃迁能级对应的特征吸收峰,在每个吸收峰附近各选出1个吸收线,利用2个吸收线对应的双吸收波长激光以及参考线对应波长激光进行掩星探测,进而由探测数据反演出温度。整个温度和水汽协同反演步骤是先反演温度廓线,然后由温度廓线以及5 km参考高度处的压强先验值计算得到压强廓线,最后在温度和压强廓线基础上,结合水汽单吸收波长和参考波长激光掩星数据,反演得到水汽分子数密度廓线。此外,本文对探测和反演过程进行了模拟仿真,通过在近红外波段选择合适的氧气吸收波长和水汽吸收波长,模拟得到掩星透过率数据,以此反演得到温度和水汽分子数密度廓线。并通过对整个过程的分析,明确了反演过程中的误差项及其传递关系,结合数值仿真结果,说明了各个误差项的影响大小。结果显示,在UTLS区间内,温度反演误差总体小于1.05 K,水汽分子数密度反演误差总体小于4%,该误差范围说明了温度和水汽协同反演方法的可行性。 相似文献
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GPS掩星数据反演中的地球扁率影响改正 总被引：2，自引：1，他引：2
采用CHAMP实测轨道数据和MSISE-90经验干大气模型，分别将地球作为圆球和椭球，前向模拟了附加相位延迟，然后对模拟数据进行反演。通过不同方案下反演温度廓线与大气模型温度廓线的比较，发现实测掩星数据的反演中，忽略地球扁率影响会给温度反演结果带来较大的误差；而采用相应方法对地球扁率影响进行改正后，温度廓线的误差明显减弱，从而证明了改正方法的正确性。 相似文献
4.
利用GPS/MET与CHAMP掩星资料反演地球中性大气参数的比较 总被引：1，自引：0，他引：1
采用Abel积分反演算法 ,在干大气模式下 ,分别针对GPS/MET与CHAMP特定掩星事件的Level2数据进行处理 ,得到了相应的折射指数与大气参数廓线。分别将反演结果与UCAR和GFZ公布的结果进行比较 ,证明了反演算法的正确性与通用性。分析了两个温度反演结果都存在系统误差和CHAMP温度反演结果误差较大的原因 ,并提出了改进建议 相似文献
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介绍了利用GPS掩星反演地球中性大气参数的原理.在实际解算中,总结出用迭代法解多普勒观测方程、数值积分法求大气折射指数、用最小二乘法模拟大气折射指数与高度的函数关系.对特定掩星事件的数据进行了反演计算,并对计算结果进行了分析. 相似文献
7.
介绍了利用GPS掩星反演地球中性大气参数的原理.在实际解算中,总结出用迭代法解多普勒观测方程、数值积分法求大气折射指数、用最小二乘法模拟大气折射指数与高度的函数关系.对特定掩星事件的数据进行了反演计算,并对计算结果进行了分析. 相似文献
8.
介绍了利用GPS掩星资料反演大气重力波势能的方法,给出了从COSMIC(constellation observing system for meteorology, ionosphere and climate)干温廓线出发,扰动温度廓线提取及势能廓线反演的具体流程,进而对2011年夏季和冬季20～30 km重力波势能的全球分布及季节变化特征进行了分析,结果与国内外已有文献基本一致。 相似文献
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利用GPS掩星资料反演地球中性大气参数折射角方法研究 总被引：2，自引：2，他引：2
对利用GPS掩星资料反演地球中性大气参数的原理作了简要介绍，在此基础上对消除电离层影响的改正方法、Abel反演积分上限的确定、上边界测量折射角的优化方法进行了探讨。针对UCAR的Level2数据，在数据预处理工作的基础上，利用特定掩星事件的数据进行了反演计算，并对计算结果进行了分析。 相似文献
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介绍利用GPS掩星数据反演大气参数的方法。对GPS/MET和CHAMP数据不同上边界和统计优化方法的反演结果进行研究和分析,并与UCAR,GFZ网上公布的结果进行对比,指出合理的上边界条件。 相似文献
11.
空基GPS遥感地球大气参数方法研究 总被引：6，自引：0，他引：6
探讨了空基无线电掩星技术应用于遥感地球大气参数方法，并将该方法编制成资料处理软件。对实测资料进行处理和分析后，给出了地球大气参数反演结果。发现指数函数外推法引入数据处理后大大改进了大气温度的归算结果，而对气压归算的影响却很小。比对结果显示我们的遥感结果同国外有关结果基本相符。 相似文献
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Georg Bergeton Larsen Stig Syndergaard Per Høeg Martin Bjært Sørensen 《GPS Solutions》2005,9(2):144-155
The Global Positioning System (GPS) radio occultation measurements obtained using the TurboRogue GPS receiver on the Danish satellite Ørsted have been processed using the single frequency method. Atmospheric profiles of refractivity and temperature are derived and validated against numerical weather prediction data from the European Centre for Medium-Range Weather Forecast (ECMWF). Results from the Ørsted GPS measurement campaign in February 2000 indicate that the single frequency method can provide retrievals with accuracy comparable to that of using two frequencies. From comparisons between measured dry temperature profiles and corresponding dry temperature profiles derived from ECMWF analysis fields, we find a mean difference of less than 0.5 K and a standard deviation of 2–4 K between 500 and 30 hPa in height. Above 30 hPa the impact of the ionosphere becomes more dominant and more difficult to eliminate using the single frequency method, and the results show degraded accuracy when compared to previous analysis results of occultation data from other missions using the dual frequency method. At latitudes less than 40° (denoted low latitudes), the standard deviation is generally smaller than at latitudes higher than 40° (denoted high latitudes). A small temperature bias is observed centered at 200 hPa for low latitudes and at 300 hPa for high latitudes. This indicates that the ECMWF analyses do not adequately resolve the tropopause temperature minimum. In the lowest part of the troposphere an observed warm bias is thought to be due to erroneous tracking of the GPS signal in cases of atmospheric multipath propagation. 相似文献
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GPS/INS navigation precision and its effect on airborne radio occultation retrieval accuracy 总被引：1，自引：1，他引：0
Paytsar Muradyan Jennifer S. Haase Feiqin Xie James L. Garrison Justin Voo 《GPS Solutions》2011,15(3):207-218
An airborne radio occultation (RO) system has been developed to retrieve atmospheric profiles of refractivity, moisture, and temperature. The long-term objective of such a system is deployment on commercial aircraft to increase the quantity of moisture observations in flight corridors in order to improve weather forecast accuracy. However, there are several factors important to operational feasibility that have an impact on the accuracy of the airborne RO results. We investigate the effects of different types of navigation system noise on the precision of the retrieved atmospheric profiles using recordings from the GNSS Instrument System for Multistatic and Occultation Sensing (GISMOS) test flights, which used an Applanix POS/AV 510 Global Positioning System (GPS)/Inertial Navigation System (INS). The data were processed using a carrier phase differential GPS technique, and then the GPS position and inertial measurement unit data were combined in a loosely coupled integrated inertial navigation solution. This study quantifies the velocity precision as a function of distance from GPS reference network sites, the velocity precision with or without an inertial measurement unit, the impact of the quality of the inertial measurement unit, and the compromise in precision resulting from the use of real-time autonomous GPS positioning. We find that using reference stations with baseline lengths of up to 760?km from the survey area has a negligible impact on the retrieved refractivity precision. We also find that only a small bias (less than 0.5% in refractivity) results from the use of an autonomous GPS solution rather than a post-processed differential solution when used in an integrated GPS/INS system. This greatly expands the potential range of an operational airborne radio occultation system, particularly over the oceans, where observations are sparse. 相似文献
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简要概述了GNSS掩星探测大气的发展历史与国内外的研究现状;详细叙述了无线电掩星反演大气参数的基本原理,主要包括几何光学下的相位反演,中性大气层、电离层、振幅的反演,分辨率的定义以及无线电掩星技术系统与标准算法和误差分析;并针对该技术的一些特点,指出了若干尚需深入解决的问题;最后展望无线电掩星观测技术在数值天气预报(NWP)等领域的发展。 相似文献
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Electron density profiles in the equatorial ionosphere observed by the FORMOSAT-3/COSMIC and a digisonde at Jicamarca 总被引：1，自引：0，他引：1
Jann-Yenq Liu Chien-Chih Lee Jhih-Yung Yang Chao-Yen Chen Bodo W. Reinisch 《GPS Solutions》2010,14(1):75-81
We examine for the first time the ionospheric electron density profiles concurrently observed by the GPS occultation experiment
(GOX) onboard the FORMOSAT-3/COSMIC (F3/C) and the ground-based digisonde portable sounder DPS-4 at Jicamarca (12°S, 283°W,
1°N geomagnetic) in 2007. Our results show that the F3/C generally underestimates the F2-peak electron density NmF2 and the
F2-peak height hmF2. On the other hand, when the equatorial ionization anomaly (EIA) pronouncedly appears during daytime,
the total electron content (TEC) derived from the radio occultation of the GPS signal recorded by the F3/C GOX is significantly
enhanced. This results in the NmF2 at Jicamarca being overestimated by the Abel inversion on the enhanced TEC during the afternoon
period. 相似文献
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We show that the amplitude of the Global Positioning System (GPS) signals in the radio occultation (RO) experiments is an indicator of the activity of the gravity waves (GW) in the atmosphere. The amplitude of the GPS RO signals is more sensitive to the atmospheric wave structures than is the phase. Early investigations used only the phase of the GPS occultation signals for statistical investigation of the GW activity in the height interval 10–40 km on a global scale. In this study, we use the polarization equations and Hilbert transform to find the 1-D GW radio image in the atmosphere by analyzing the amplitude of the RO signal. The radio image, also called the GW portrait, consists of the phase and amplitude of the GW as functions of height. We demonstrate the potential of this method using the amplitude data from GPS/Meteorology (GPS/MET) and satellite mission Challenge Mini-satellite Payload (CHAMP) RO events. The GW activity is nonuniformly distributed with the main contribution associated with the tropopause and the secondary maximums related to the GW breaking regions. Using our method we find the vertical profiles of the horizontal wind perturbations and its vertical gradient associated with the GW influence. The estimated values of the horizontal wind perturbations are in fairly good agreement with radiosonde data. The horizontal wind perturbations v(h) are ±1 to ±5 m s with vertical gradients dv/dh ±0.5 to ±15 m s km at height 10–40 km. The height dependence of the GW vertical wavelength was inferred through the differentiation of the GW phase. Analysis of this dependence using the dispersion relationship for the GW gives the estimation of the projection of the horizontal background wind velocity on the direction of the GW propagation. For the event considered, the magnitude of this projection changes between 1.5 and 10 m s at heights of 10–40 km. We conclude that the amplitude of the GPS occultation signals contain important information about the wave processes in the atmosphere on a global scale. 相似文献