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Precipitable water vapor (PWV) is an important parameter for climate research and a crucial factor to achieve high accuracy in satellite geodesy and satellite altimetry. Currently Global Navigation Satellite System (GNSS) PWV retrieval using static Precise Point Positioning is limited to ground stations. We demonstrated the PWV retrieval using kinematic Precise Point Positioning method with shipborne GNSS observations during a 20-day experiment in 2016 in Fram Strait, the region of the Arctic Ocean between Greenland and Svalbard. The shipborne GNSS PWV shows an agreement of similar to 1.1 mm with numerical weather model data and radiosonde observations, and a root-mean-square of similar to 1.7 mm compared to Satellite with ARgos and ALtiKa PWV. An improvement of 10% is demonstrated with the multi-GNSS compared to the Global Positioning System solution. The PWV retrieval was conducted under different sea state from calm water up to gale. Such shipborne GNSS PWV has the promising potential to improve numerical weather forecasts and satellite altimetry.

Plain Language Summary Atmospheric water vapor retrieval using GNSS kinematic Precise Point Positing technique is demonstrated with shipborne GNSS data collected during a 20-day cruise in Fram Strait (similar to 80 degrees N), the area in the Arctic Ocean between Greenland and Svalbard. An accuracy of similar to 1 mm is achieved compared to ERA-Interim precipitable water vapor (PWV) and radiosonde data, and an agreement of similar to 2 mm is demonstrated between shipborne GNSS PWV and satellite altimetry PWV observation. The contribution of multi-GNSS is addressed, and efforts are also made to investigate the PWV spatial resolution in order to include more data for comparison. Static Precise Point Positioning method is widely used at ground-based GNSS stations in climate research and weather forecasting. However, it is still limited to land. Shipborne GNSS PWV retrieval could fill in the vast ocean with high temporal/spatial resolutions. Shipborne GNSS PWV could cover open sea, coastal, and polar regions (e.g., in this study) where regular meteorological observations are rare. Shipborne GNSS PWV retrieval in real time is feasible and could provide additional information for weather predictions. Moreover, shipborne GNSS PWV retrieval provides a potential method for satellite altimetry calibration, the major technique measuring sea surface height for sea level monitoring.