Retrieval of high-precision precipitable water vapour maps using Sentinel-1A and Beidou satellite data

ABSTRACT

Precipitable water vapour (PWV) is a primary factor that affects climate and weather. The accurate retrieval of PWV is crucial for weather prediction and meteorological research. Interferometric Synthetic Aperture Radar (InSAR) has been rapidly developed in recent years and proven effective in PWV retrieval in the regions of good coherence. However, there are large areas of natural terrain where signals decoherence that limit the precision of PWV retrieval. Besides, due to the differential interference processing of InSAR data, the results of its retrieval are differential PWV (ΔPWV). In this study, the StaMPS-InSAR was used to overcome the problem of weak detection ability in low coherence regions. A series of 11 Sentinel-1A images were selected to retrieve space-continuous ΔPWV. Beidou Satellite Navigation System (BDS) can retrieve high-precision PWV. Hence, the BDS data was utilized to convert the InSAR-derived ΔPWV to PWV. Compared with the BDS-derived PWV, the root mean square error (RMSE) of the experimental results is 1.3 mm with a spatial resolution as fine as 20 m. The correlation coefficient between the deviations and Liquid Cloud Water is 0.65, indicating a positive correlation. We demonstrate the advantage of the proposed method for retrieving PWV in computational efficiency by comparing it with the SBAS-InSAR. With the increasing stack size of the SAR images, our method can reduce the taking time for processing. The proportion can reach 12.6% when the stack size of SAR images is 20. By the spatio-temporal analysis of the results, we found some characteristics of PWV in mountain areas especially. The results have certain reference value for the space-continuous PWV retrieval and the study of PWV spatio-temporal characteristics.

KEYWORDS:

• Retrieval of PWV
• StaMPS-InSAR
• Sentinel-1
• Beidou navigation system (BDS)
• Non-differential PWV

Acknowledgements

This work was supported by the Shandong Provincial Natural Science Foundation, China (ZR2021QD155, ZR2020QD049, ZR2017MD029), in part by the State Key Laboratory of Geodesy and Earth’s Dynamics (Institute of Geodesy and Geophysics, CAS) under grant (SKLGED2021-5-5). The authors are grateful to the support from Academician Zhou Chenghu’s team, Shandong Jianzhu University. Also, we would like to thank the European Space Agency (ESA) for free access to the Sentinel -1A satellite data and SNAP tool. We would like to thank the Shandong Provincial Institute of Land Surveying and mapping for providing CORS data. The authors greatly appreciate the editors and the anonymous Reviewers on this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the the State Key Laboratory of Geodesy and Earth’s Dynamics (Institute of Geodesy and Geophysics, CAS) [SKLGED2021-5-5]; the Shandong Provincial Natural Science Foundation, China [ZR2021QD155, ZR2020QD049, ZR2017MD029].