Real-Time GNSS-Derived PWV for Typhoon Characterizations: A Case Study for Super Typhoon Mangkhut in Hong Kong

He, Qian; Zhang, Kefei; Wu, Suqin; Zhao, Qingzhi; Wang, Xiaoming; Shen, Zhen; Li, Longjiang; Wan, Moufeng; Liu, Xiaoyang

doi:10.3390/rs12010104

Cited by 33 publications

(13 citation statements)

References 56 publications

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“…their correlation was positive, while the correlation between PWV and the distance of the center of the TC was negative. This result was consistent with the ones found in several cases [22]- [24]. In addition, the grade of a TC in a region can be determined by wind speed, as shown in Table 7.…”

Section: Temperal Variation In Pwv During Tropical Cyclonessupporting

confidence: 91%

“…Since a large PWV value above each GNSS station was mainly brought by a TC, as a signal at the station, the time of PWV arrival (TOPA) may be used to indicate the movement status of the TC. Based on the times of the signals occurred over several stations, the movement of a typhoon can be estimated, which can be found from very recent researches [21], [22]. However, these study cases were only from super typhoons.…”

Section: F Using Gnss-pwv Signals To Monitor Tropical Cyclonesmentioning

confidence: 99%

“…TC1) is much larger than the distance between two adjacent GNSS stations, the edge of the TC could be considered a line. In the literatures [21], [22], the TCs with smaller radii were not analyzed. Fig.…”

Section: F Using Gnss-pwv Signals To Monitor Tropical Cyclonesmentioning

confidence: 99%

“…At present, some studies proved that the variation in GNSS-PWV could reflect a typhoon's life and so GNSS-PWV can be used to forecast short-term rainfall during the typhoon's period [19], [20]. In addition, some researchers proposed to use PWV time series over several GNSS ground tracking stations in a region to estimate the movements of a super typhoon [21], [22]. Many results were based on only one TC case, especially for super typhoons [23]- [25], which might not sufficiently reveal the true characteristics of water vapor or may not be applicable to other cases.…”

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confidence: 99%

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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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Section: Temperal Variation In Pwv During Tropical Cyclonessupporting

confidence: 91%

Section: F Using Gnss-pwv Signals To Monitor Tropical Cyclonesmentioning

confidence: 99%

Section: F Using Gnss-pwv Signals To Monitor Tropical Cyclonesmentioning

confidence: 99%

mentioning

confidence: 99%

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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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“…ERA5 monthly mean data are available here: https://doi.org/10.24381/cds.6860a573 (Hersbach et al, 2019). ERA5 hourly data are available here: https://doi.org/10.24381/cds.bd0915c6 (Hersbach et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

A new global grid-based weighted mean temperature model considering vertical nonlinear variation

Sun

Zhang

et al. 2021

Atmos. Meas. Tech.

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Abstract. Global navigation satellite systems (GNSS) have been proved to be an excellent technology for retrieving precipitable water vapor (PWV). In GNSS meteorology, PWV at a station is obtained from a conversion of the zenith wet delay (ZWD) of GNSS signals received at the station using a conversion factor which is a function of weighted mean temperature (Tm) along the vertical direction in the atmosphere over the site. Thus, the accuracy of Tm directly affects the quality of the GNSS-derived PWV. Currently, the Tm value at a target height level is commonly modeled using the Tm value at a specific height and a simple linear decay function, whilst the vertical nonlinear variation in Tm is neglected. This may result in large errors in the Tm result for the target height level, as the variation trend in the vertical direction of Tm may not be linear. In this research, a new global grid-based Tm empirical model with a horizontal resolution of 1∘ × 1∘ , named GGNTm, was constructed using ECMWF ERA5 monthly mean reanalysis data over the 10-year period from 2008 to 2017. A three-order polynomial function was utilized to fit the vertical nonlinear variation in Tm at the grid points, and the temporal variation in each of the four coefficients in the Tm fitting function was also modeled with the variables of the mean, annual, and semi-annual amplitudes of the 10-year time series coefficients. The performance of the new model was evaluated using its predicted Tm values in 2018 to compare with the following two references in the same year: (1) Tm from ERA5 hourly reanalysis with the horizontal resolution of 5∘ × 5∘; (2) Tm from atmospheric profiles from 428 globally distributed radiosonde stations. Compared to the first reference, the mean RMSEs of the model-predicted Tm values over all global grid points at the 950 and 500 hPa pressure levels were 3.35 and 3.94 K, respectively. Compared to the second reference, the mean bias and mean RMSE of the model-predicted Tm values over the 428 radiosonde stations at the surface level were 0.34 and 3.89 K, respectively; the mean bias and mean RMSE of the model's Tm values over all pressure levels in the height range from the surface to 10 km altitude were −0.16 and 4.20 K, respectively. The new model results were also compared with that of the GTrop and GWMT_D models in which different height correction methods were also applied. Results indicated that significant improvements made by the new model were at high-altitude pressure levels; in all five height ranges, GGNTm results were generally unbiased, and their accuracy varied little with height. The improvement in PWV brought by GGNTm was also evaluated. These results suggest that considering the vertical nonlinear variation in Tm and the temporal variation in the coefficients of the Tm model can significantly improve the accuracy of model-predicted Tm for a GNSS receiver that is located anywhere below the tropopause (assumed to be 10 km), which has significance for applications requiring real-time or near real-time PWV converted from GNSS signals.

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Observational study of Super Typhoon Saola in 2023 when it was close to Hong Kong

Chan,

Choy,

Chiu

et al. 2024

Weather

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Super Typhoon Saola came very close to Hong Kong on 1/2 September 2023, necessitating the issuance of the No. 10 hurricane signal, the highest tropical cyclone warning signal in Hong Kong. While there was widespread damage in Hong Kong, no people were killed in the event with effective early warning. It is rare that a super typhoon comes very close to Hong Kong, and this paper is a part in the series of the documentation of Saola to summarize the interesting observations of Saola near Hong Kong for future reference by weather forecasters.

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Real-Time GNSS-Derived PWV for Typhoon Characterizations: A Case Study for Super Typhoon Mangkhut in Hong Kong

Cited by 33 publications

References 56 publications

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

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

A new global grid-based weighted mean temperature model considering vertical nonlinear variation

Observational study of Super Typhoon Saola in 2023 when it was close to Hong Kong

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