A New Method for Refining the GNSS-Derived Precipitable Water Vapor Map

Liu, Chen; Zheng, Nanning; Zhang, Kefei; Liu, Junyu

doi:10.3390/s19030698

Cited by 12 publications

(10 citation statements)

References 38 publications

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“…Among the 11 GNSS stations, the elevation of station JZ88 is much higher than other stations (see Table 1). This discovery is consistent with the previous studies that the GNSS-PWV tends to decrease with the increasing elevation (Liu et al, 2019a;Onn & Zebker, 2006). From the above analysis, there is a strong correlation between GNSS-derived PWV and rainfall.…”

Section: Pwv Time Characteristicssupporting

confidence: 92%

Spatiotemporal characteristics of GNSS-derived precipitable water vapor during heavy rainfall events in Guilin, China

Huang

Xie

et al. 2021

Satell Navig

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Precipitable Water Vapor (PWV), as an important indicator of atmospheric water vapor, can be derived from Global Navigation Satellite System (GNSS) observations with the advantages of high precision and all-weather capacity. GNSS-derived PWV with a high spatiotemporal resolution has become an important source of observations in meteorology, particularly for severe weather conditions, for water vapor is not well sampled in the current meteorological observing systems. In this study, an empirical atmospheric weighted mean temperature (Tm) model for Guilin is established using the radiosonde data from 2012 to 2017. Then, the observations at 11 GNSS stations in Guilin are used to investigate the spatiotemporal features of GNSS-derived PWV under the heavy rainfalls from June to July 2017. The results show that the new Tm model in Guilin has better performance with the mean bias and Root Mean Square (RMS) of − 0.51 and 2.12 K, respectively, compared with other widely used models. Moreover, the GNSS PWV estimates are validated with the data at Guilin radiosonde station. Good agreements are found between GNSS-derived PWV and radiosonde-derived PWV with the mean bias and RMS of − 0.9 and 3.53 mm, respectively. Finally, an investigation on the spatiotemporal characteristics of GNSS PWV during heavy rainfalls in Guilin is performed. It is shown that variations of PWV retrieved from GNSS have a direct relationship with the in situ rainfall measurements, and the PWV increases sharply before the arrival of a heavy rainfall and decreases to a stable state after the cease of the rainfall. It also reveals the moisture variation in several regions of Guilin during a heavy rainfall, which is significant for the monitoring of rainfalls and weather forecast.

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Section: Pwv Time Characteristicssupporting

confidence: 92%

Spatiotemporal characteristics of GNSS-derived precipitable water vapor during heavy rainfall events in Guilin, China

Huang

Xie

et al. 2021

Satell Navig

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“…Thus, a regional T m regression model developed based on surface meteorological measurement data is commonly used. At present, the main regional T m models include three types: 1) single meteorological factor linear model (SMLM) like the relationship between surface temperature T s and T m expressed in [43]- [45]; 2) single meteorological factor non-linear model (SMNLM), like the relationship of T s and T m stated in [46]; 3) multiple meteorological factors model (MMFM), like the relationship among T s , surface pressure P s and T m expressed in [47], [48]. The SMLM, SMNLM and MMFM can be expressed as (9), (10) and (11), respectively.…”

Section: B Accuracy Of T Mmentioning

confidence: 99%

Precipitable Water Vapor Converted from GNSS-ZTD and ERA5 Datasets for the Monitoring of Tropical Cyclones

Shen

Wan

et al. 2020

IEEE Access

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Tropical cyclones (TCs) are intense rotating storm systems, characterized by strong winds, heavy humidity and storm surges, and usually cause an abnormal increase in regional water vapor during the period of their occurrence. Global navigation satellite system (GNSS) is well-established and initially mainly for positioning, navigation and timing. However, due to their global coverage and 24/7 operability under all weather conditions, GNSS has been widely used in meteorology such as the retrieval of precipitable water vapor (PWV). Since PWV time series obtained from a regional ground GNSS tracking stations network has high temporal and spatial resolutions, in this research, the temporal and spatial variation trends of regional PWVs during several TCs' periods in Hong Kong were investigated, and a new method using high-resolution GNSS-PWV time series to estimate a TC's movement was proposed. Test data were from 15 GNSS tracking stations equipped with meteorological sensors, and three GNSS stations without meteorological sensors but using meteorological data interpolated from ERA5 (fifth-generation reanalysis dataset of the European Centre for Medium-range Weather Forecasting) dataset, and six TC events occurred in 2017 were selected for cases studies. Moreover, for a better accuracy of GNSS-PWV, which is converted from the zenith wet delay of the GNSS signal multiplying a conversion factor that uses a weighted mean temperature (T m), a seasonal multi-factor T m model was established and tested. Results showed that the new T m model outperformed the previous regional T m model used in Hong Kong. In addition, based on the temporal variation trend and spatial distribution of the regional PWV, one can determine if a TC approaches the region. A geometric approach to estimating a TC's movement was developed and its test results agreed well with the truth. These results suggest the potential of using GNSS signals to monitor the movements of TCs for short-time TC forecasting due to their high temporal resolution. INDEX TERMS Tropical cyclone, global navigation satellite system, precipitable water vapor, weighted mean temperature, ERA5. I. INTRODUCTION Over recent years, increasing tropical cyclone (TC) events occurred frequently in the North Pacific, Indian Ocean, Southwest Pacific and North Atlantic, causing considerable damage in nearby cities [1]-[5]. Many countries, provinces and cities have set up meteorological departments, which take the early warning and forecasting of TCs as a key task. Water vapor, as a main component of the atmosphere, is a key factor The associate editor coordinating the review of this manuscript and approving it for publication was Gerardo Di Martino. influencing TCs' development [6], [7]. The monitoring of regional water vapor variation is critical for the forecasting of the movement, intensity and rainfall of TCs [8]-[10]. Traditional techniques for the acquisition of atmospheric water vapor, such as infrared satellite remote sensing, radiosondes (RS) and microwave radiometers, have the disa...

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“…The original WV product is two-dimensional (2D) precipitable WV (PWV) retrieved from GNSS observations, having the same accuracy as those of the measures obtained using the traditional meteorological technology (e.g., radiosonde (RS) and WV radiometer), which has attracted considerable attention [10][11][12]. Furthermore, extensive GNSS WV remote sensing experiments have been carried out worldwide, including those in China [13], North America [14], and Europe [15], which jointly verify the reliability of the GNSS-derived PWV.…”

Section: Introductionmentioning

confidence: 99%

A New GNSS-Derived Water Vapor Tomography Method Based on Optimized Voxel for Large GNSS Network

Yao

Liu

2020

Remote Sensing

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The Global Navigation Satellite System (GNSS) tomographic technique can be used for remote sensing of the three-dimensional water vapor (WV) distribution in the troposphere, which has attracted considerable interest. However, a significant problem in this technique is the excessive reliance on constraints (particularly in large GNSS networks). In this paper, we propose an improved tomographic method based on optimized voxel, which only considers the voxels passed by GNSS rays. The proposed method can completely prevent the tomographic algorithm interference of constraints that originated from empirical functions. Experiments in Nanjing in the periods of day-of-year (DOY) 182–184, 2019, and 244–246, 2019, show that the mean absolute error (MAE) and root mean square error (RMSE) of the WV density profile obtained using the proposed method are 0.9 and 1.3 g/m3, while those obtained using the conventional method are 1.3 and 1.8 g/m3, respectively, with respect to the radiosonde (RS) method. The numerical results show that the proposed method is reliable and has a superior accuracy to that of the conventional method.

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A New Method for Refining the GNSS-Derived Precipitable Water Vapor Map

Cited by 12 publications

References 38 publications

Spatiotemporal characteristics of GNSS-derived precipitable water vapor during heavy rainfall events in Guilin, China

Spatiotemporal characteristics of GNSS-derived precipitable water vapor during heavy rainfall events in Guilin, China

Precipitable Water Vapor Converted from GNSS-ZTD and ERA5 Datasets for the Monitoring of Tropical Cyclones

A New GNSS-Derived Water Vapor Tomography Method Based on Optimized Voxel for Large GNSS Network

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