Meet Our Met Team! (2022)

Micro-Laboratory of Atmospheric Research and Geomatics Engineering (Micro-LARGE)

Department of Land Surveying and Geo-Informatics, Faculty of Construction and Environment, The Hong Kong Polytechnic University

  • Team supervisor: Prof. Zhizhao (George) Liu
  • Our group currently (October 2022) has 7 Ph.D. students and 1 part-time research assistant.

Establishing a new GNSS station for ionosphere scintillation monitoring at Sanya, Hainan, Mainland China, on 26 December 2015. L to R: Prof. Ning of Chinese Academy of Sciences, Prof. George Liu of Hong Kong Polytechnic University, and Dr. Zhe Yang, a former PhD student in Prof. Liu’s group.

Group members had a dinner on 13th August 2021 to celebrate Dr. Jia He’s (right in the first row) successful PhD oral examination.

Dr. Biyan Chen, former PhD student in Prof. Liu’s Lab, did a GNSS signal reception experiment on a high-speed train in Mainland China on 9 November 2017.

Group members in front of the CMACast antenna, which was installed by Prof. Liu’s Lab on the roof top of Block Z building, Hong Kong Polytechnic University on 9 September 2015.

Group members with visitor Prof. Gérard Lachapelle (third from the left), an internationally renowned GNSS authority, taken at Hong Kong Polytechnic University on 29 March 2016.

High precision global water vapor data to share with the community

Over the past a few years, the Micro-LARGE Lab has been developing novel algorithms to enhance the observation accuracy of global water vapor data from multiple sensors/satellites, including FY series, MODIS, Sentinel-3, etc. Our algorithms can improve the global water vapor accuracy by up to 50-60% under clear sky condition. Under cloudy conditions, we have also specialized algorithm to correct the cloud effect on satellite water vapor observation. With that, our preliminary analysis showed that the global water vapor accuracy can be significantly improved by approximately 50%.

We are now assimilating water vapor data from multiple sensors/satellites into numerical weather prediction model such as WRF. Preliminary results have shown positive impact of the satellite water vapor data, particularly the ones with improved accuracy.

We will be happy to collaborate with the global meteorological community and share the high precision water vapor data with the collaborators for different applications.

Contact us

Prof. Zhizhao (George) Liu
Tel: (852) 2766-5961

Block Z (Phase 8), The Hong Kong Polytechnic University (PolyU)
181 Chatham Road South
Hung Hom, Kowloon, Hong Kong
P.R. China

Publications in recent three years (total IF=149.340, average IF = 6.222 per paper. Names with * are students or research assistants):

  1. Xue, Dabin*, Jian Yang, Zhizhao Liu, Bing Wang (2022), An optimized solution to long-distance flight routes under extreme cosmic radiation, Space Weather, accepted. IF:4.288.
  2. Xu, Jiafei*, Zhizhao Liu (2022), A Back Propagation Neural Network Based Algorithm For Retrieving All-Weather Precipitable Water Vapor From MODIS NIR Measurements. IEEE Transactions on Geoscience and Remote Sensing, accepted. IF: 8.125.
  3. Xu, Jiafei*, Zhizhao Liu (2022), Enhanced All-weather Precipitable Water Vapor Retrieval from MODIS Near-infrared Bands Using Machine Learning, The International Journal of Applied Earth Observation and Geoinformation, Accepted. IF: 7.672.
  4. Xu, Jiafei*, Zhizhao Liu (2021), Evaluation of Precipitable Water Vapor Product from MODIS and MERSI-II NIR Channels Using Ground-based GPS Measurements over Australia, IEEE JSTARS, accepted. IF: 4.715.
  5. Xu, Jiafei*, Zhizhao Liu (2022), A Linear Regression of Differential PWV Calibration Model to Improve the Accuracy of MODIS NIR All-weather PWV Products Based on Ground-based GPS PWV Data, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (JSTARS), accepted. IF: 4.715.
  6. Gao Zhiqiu, Jianbin Zhang, Miao Yu, Zhizhao Liu, Ruoying Yin, Shaohui Zhou, Lian Zong, Guicai Ning, Xiaoze Xu, Yunqian Guo, Han Wei, Yuanjian Yang (2022), Role of water vapor modulation from multiple pathways in the occurrence of a record-breaking heavy rainfall event in China in 2021, Earth and Space Science, accepted. IF: 3.68.
  7. Gao Rui, Zhizhao Liu, and Baocheng Zhang (2022), Ionosphere-weighted post-processing kinematic for airborne positioning with refined modeling of receiver phase biases and tropospheric zenith wet delays, GPS Solutions, Accepted. IF: 4.517.
  8. Tang, Xu, Zhizhao Liu, Gethin Wyn Roberts, Craig Matthew Hancock (2022), PPP-derived tropospheric ZWD augmentation from local CORS network tested on bridge monitoring points, Advances in Space Research, Vol 69, Issue 10, Pages 3633-3643, IF=2.611.
  9. Yu, Shiwei*, Zhizhao Liu, Tsz Cheung Lee (2021), Ionospheric Disturbances Observed from a Single GPS Station in Hong Kong During the Passage of Super Typhoon Hato in 2017, Space Weather, Vol. 20, Issue 1,, IF: 4.288.
  10. Xue, Dabin*, Jian Yang, and Zhizhao Liu (2022). Potential Impact of GNSS Positioning Errors on the Satellite-navigation-based Air Traffic Management. Space weather. JCR: Q1, accepted. IF: 4.288.
  11. Gong, Yangzhao*, Zhizhao Liu, James H. Foster (2021), Evaluating the Accuracy of Satellite-based Microwave Radiometer PWV Products Using Shipborne GNSS Observations across the Pacific Ocean, Transactions on Geoscience and Remote Sensing (TGRS), accepted. IF: 8.125.
  12. Xu, Jiafei*, Zhizhao Liu (2021), Radiance-based Retrieval of Total Water Vapor Content from Sentinel-3A OLCI NIR Channels Using Ground-based GPS Measurements, International Journal of Applied Earth Observation and Geoinformation, Volume 104, 102586., IF: 7.672.
  13. Xu, Jiafei*, Zhizhao Liu (2021), The First Validation of Sentinel-3 OLCI Integrated Water Vapor Products Using Reference GPS Data in Mainland China, IEEE Transactions on Geoscience and Remote Sensing (TGRS), accepted 2021. IF: 8.125.
  14. Yu, Shiwei*, Zhizhao Liu (2021), The Ionospheric Condition and GPS Positioning Performance during the 2013 Tropical Cyclone Usagi Event in the Hong Kong Region, Earth Planets Space, 73(1): 66. IF: 3.362.
  15. He, Jia*, Zhizhao Liu (2021), Water Vapor Retrieval from MERSI NIR Channels of Fengyun-3B Satellite Using Ground-based GPS Data, Remote Sensing of Environment, 258: 112384., 11 pages, IF: 13.85.
  16. Yu, Shiwei*, Zhizhao Liu (2021), Tropical cyclone-induced periodical positioning disturbances during the 2017 Hato in the Hong Kong region, GPS Solutions, 25(3): 109. IF: 4.517.
  17. He, Jia*, Zhizhao Liu (2021), Applying the New MODIS-Based Precipitable Water Vapor Retrieval Algorithm Developed in the North Hemisphere to the South Hemisphere, IEEE Transactions on Geoscience and Remote Sensing (TGRS), vol. 60, pp. 1-12, 2022, Art no. 4100812, doi: 10.1109/TGRS.2021.3059876, 12 pages, IF: 8.125.
  18. Yu, Shiwei*, Zhizhao Liu (2020), Temporal and Spatial Impact of the Precipitable Water Vapor on the GPS Relative Positioning during the Hato (2017) in Hong Kong and Taiwan Regions, Earth and Space Science, 8(4): e2020EA001371. IF: 3.68.
  19. Gong, Yangzhao*, Zhizhao Liu (2020), Evaluating the Accuracy of Jason-3 Water Vapor Product Using PWV Data from Global Radiosonde and GNSS Stations, IEEE Transactions on Geoscience and Remote Sensing (TGRS), 59(5): 4008–4017., 10 pages. IF: 8.125.
  20. Li, Guozhu, Baiqi Ning, Yuichi Otsuka, Mangalathayil Ali Abdu, Prayitno Abadi, Zhizhao Liu, Luca Spogli, and Weixing Wan (2020), Challenges to equatorial plasma bubble and ionospheric scintillation short-term forecasting and future aspects in East and Southeast Asia, Surveys in Geophysics, DOI: 10.1007/s10712-020-09613-5. IF: 7.965.
  21. He, Jia*, Zhizhao Liu (2020), Refining MODIS NIR Atmospheric Water Vapor Retrieval Algorithm Using GPS-derived Water Vapor Data. IEEE Transactions on Geoscience and Remote Sensing (TGRS), 59(5): 3682–3694., 13 pages, IF: 8.125
  22. Zhu, Mingchen*, Zhizhao Liu, Wusheng Hu (2020), Observing Water Vapor Variability during Three Super Typhoon Events in Hong Kong Based on GPS Water Vapor Tomographic Modeling Technique, Journal of Geophysical Research: Atmospheres, Vol. 125, No 15, IF: 5.217,, 20 pages.
  23. He, Jia*, Zhizhao Liu (2020), Water Vapor Retrieval from MODIS NIR Channels Using Ground-Based GPS Data. IEEE Transactions on Geoscience and Remote Sensing (TGRS), 58 (5): 3726–37, 12 pages,, IF: 8.125
  24. Xue, Dabin*, Zhizhao Liu, Bing Wang, Jian Yang (2021), Impacts of COVID-19 on aircraft usage and fuel consumption: a case study on four Chinese international airports, Journal of Air Transport Management, 95: 102106., IF: 5.428.

Tell us about your team!

It can be a department, a research group or a secondary school society related to meteorology.
Email us ( with the following information:
a) the name of your team;
b) some group photos or relevant pictures;
c) composition of your team;
d) a few sentences about your team; and
e) titles of a couple of recent papers published, or activities organised.