Preliminary results from the first deployments of the Dynamic Ocean Topography Buoy: in-situ observations of sea surface height in ice-covered seas.

The Dynamic Ocean Topography buoy provides full GPS data to allow Precise Point Positioning determination of sea surface height (SSH) with centimeter-scale accuracy. This is to allow us to receive in-situ height data useable for calibration/validation of ICESat-2 observations over long periods of time. The buoy supports a survey grade dual frequency GPS receiver and buffers the full GPS data gathered every 30 seconds over remotely programmable periods of at least several days, allowing us to resolve major tidal constituents as well as other relatively high-frequency SSH variability unresolvable from remote sensing. The data are telemetered through an Iridium link. The dual frequency GPS also allows the calculation of integrated precipitable water vapor based on returns from the different GPS frequencies. A fine scale pressure sensor measures the freeboard of the GPS antenna phase center, a barometer measures atmospheric pressure to allow correction for the inverse barometer effect, and atmospheric temperature is measured for use in the determination of precipitable water vapor. The standard meteorological measurements further augment the existing International Arctic Buoy Program drifting array in the Arctic Ocean. In this presentation, we will present results from a test deployment in Elson Lagoon, Alaska in April-May 2019 as well as preliminary results from the first two extended deployments. One buoy is scheduled to be deployed in the Canada Basin as part of the Stratified Ocean Dynamics of the Arctic Ocean/Coordinated Arctic Acoustic Experiment Cruise onboard the USCGC Healy in September 2019. The other buoy will be deployed in the Eurasian Basin on MOSAIC leg 1 from the R/V Akademik Fedorov. The preliminary results from the DOT buoys will be compared to the SSH products from both the ICESAT-2 and CryoSat-2 satellites. We also plan to explore previously unknown modes of high-frequency variability of dynamic ocean topography in both the Canada and Eurasian Basins. Finally, a comparison between in-situ precipitable water vapor measured by the buoy and various atmospheric reanalysis products will be shown.