Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： The unique combination of global coverage, high precision, high vertical resolution, long-term stability and all-weather viewing of radio occultation will enhance the data sets of numerical weather prediction and improve the precision of Numeric Weather Prediction (NWP). And data assimilation requires preprocessing of the raw radio signals into the bending angles and refractivity. Then the atmospheric parameters such as temperature, pressure and humidity can be retrieved through data variational assimilation. The procedures for processing of radio occultation data, especially several important steps are introduced. And comparative analysis between these results and those from CDAAC shows that below the altitude of 30 km, the relative errors of refractivity, pressure and humidity are within 2% and the deviation of temperature is below 2K. The results are also compared with the data from ERA-interim model of ECMWF and similar conclusion is obtained.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The unique combination of global coverage, high precision, high vertical resolution, long-term stability and all-weather viewing of radio occultation will enhance the data sets of numerical weather prediction and improve the precision of Numeric Weather Prediction (NWP). And data assimilation requires preprocessing of the raw radio signals into the bending angles and refractivity. Then the atmospheric parameters such as temperature, pressure and humidity can be retrieved through data variational assimilation. The procedures for processing of radio occultation data, especially several important steps are introduced. And comparative analysis between these results and those from CDAAC shows that below the altitude of 30 km, the relative errors of refractivity, pressure and humidity are within 2% and the deviation of temperature is below 2K. The results are also compared with the data from ERA-interim model of ECMWF and similar conclusion is obtained.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics Subjects: Geosciences >> Marine Sciences submitted time 2016-05-13
Abstract：全球卫星导航定位系统的反射信号(GNSS-R)遥感是反演陆地和海洋表面地球物理参数的有力工具.而机载GNSS-R是一个很重要的实验平台,因为它不仅可以为空基实验提供校准依据,而且在中小尺度目标(比如河流和湖泊)的遥感方面独具优势.机载实验的研究主要包括海面风场的反演、海面高度的测量和土壤湿度的探测.首次反演海面风场和土壤湿度的机载GNSS-R实验都是由美国NASA和科罗拉多州立大学组织实施的.之后在西班牙IEEC(Institut d'Estudis Espacials de Catalunya)/CSIC(Consejo Superior de Investigaciones Cientificas)、Starlab实验室与NASA的联合实验中,海面风场的反演精度已经能够达到2 m/s.两个最早利用GNSS-R探测海面高度的机载GNSS-R实验都是美国的JPL(Jet Propulsion Laboratory)组织实施的,其中海面平均高度的探测精度已经达到了厘米级.在中国,北京航空航天大学和中国科学院遥感与数字地球研究所也组织了相应的机载GNSS-R实验.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-03
Abstract： The radio occultation (RO) technique using signals from the global navigation satellite system, is widely used to observe the atmosphere for applications such as numerical weather prediction (NWP) and global climate monitoring. Since 1995, there have been turborogue sounder on board global positioning system/meteorology, black jack sounder on board challenging minisatellite payload and gravity recovery and climate experiment, IGOR sounder on board constellation observing system for meteorology, ionosphere and climate, GRAS on board meteorological operational, which have been recieving a large number of RO data, but their observed signals come only from global positioning system (GPS). These RO data have been wildly used in NWP and climate monitoring, however they cannot meet the requirements for high accuracy and real time atmosphere observation, in this case compatible RO sounder to obtain more RO observations is significant. Global navigation satellite system occultation sounder (GNOS) on board the fengyun3 C (FY3 C) satellite, which is the first Bei Dou system (BDS)/GPS compatible RO sounder in the world, was launched on 23 September 2013. Up to now, lots of RO observations have been obtained. In this study, the components of GNOS are introduced; one-day GNOS RO events and their global distribution are analyzed; compared with the GPS RO observations, the accuracy and consistency of BDS real-time positioning results and BDS RO products are analyzed. The preliminary results show that the BDS can enhance the number of RO events by 33.3%; the average deviation and standard deviation of BDS real time positioning results are 6 m and 7 m, respectively; the BDS/GPS difference standard deviation of refrectivity, temperature, humidity, pressure and ionospheric electron density are lower than 2%, 2 K, 1.5 g/kg, 2%, and 15.6%, respectively. The BDS observations/products are consistent with those of GPS, therefore BDS RO products can bring benefit to numerical wheather prediction and global chlimate change analysis.
Peer Review Status:Awaiting Review
Hits
Hits
Downloads
Comment