Data Accompanying “Direct observations of near-inertial wave zeta-refraction in a dipole vortex”

This archives includes: ---------------- drifter_data.mat: Position information of the surface drifters (SVP and SVP-B; Centurioni, 2018) deployed by Centurioni and Hormann as part of NISKINe. Only positions relevant to the paper, between 27 May and 6 June 2019 are included. The structure array 'drifters' includes the time (in Matlab's datenum, regular hourly grid), longitude and latitude of the drifters, and low-pass velocity estimated from the drifter positions and a 2 inertial periods (2 x 14.1 hours). ---------------- ship_data.mat Position, wind, and ocean velocity data from R/V Armstrong, from 27 May to 30 June 2019. Ocean velocity data is from the 150 kHz OceanSurveyor Narrowband ADCP (os150nb), processed using the University of Hawaii's CODAS (Common Ocean Data Access System) procedure. Wind velocity (uwnd, vwnd, positive in the direction where the wind is going) from the Vaisala anemometer on the port side of the ship is included. ---------------- OBJECTIVE MAPS: The background velocity and vorticity field is estimated using all available velocity observations. The ship ADCP data is averaged vertically between 50 and 250 m in 10- min regular bins. Lagrangian drifters (SVP and SVP-B) are drogued at 15 m depth and report their position hourly (Centurioni, 2018). Drifter trajectories are low-passed using a running average of hourly positions over 2 inertial periods (28.2 hours). Sub-inertial velocities are estimated from low-oats trajectories. Data from 44 drifters were used in the estimation of the maps, 31 of which within 100 km of the confluence survey. The resulting velocity vectors are mapped into a scalar streamfunction (surface pressure map) using objective analysis techniques (Freeland & Gould, 1976; Bretherton et al., 1976). The satellite-derived Aviso geostrophic velocity are used as background for the objective map (Ducet et al., 2000). These 'delayed-time' absolute dynamical topography are downloaded from Copernicus Marine Environment Monitoring Service, a data center supported by the European Union. The Aviso products have much larger temporal (10 days) and spatial scales (150 km) as our final products, but provide a good starting point. Maps calculated with 30 and 50 km spatial decorrelation scales are used. The range of spatial scales used is consistent with decorrelation length scales estimated from covariance of data versus spatial or temporal distance, from either velocity or tracer fields. Time scale is always 4 inertial periods. In each structure array, variables include the distance (x: easting in km, and y: northing in km) from a reference (lon0 and lat0), the central time of each estimate (time), the streamfunction expressed in terms of dynamic height (ssh), formal error of the streamfunction from the objective analysis (error), the associated vorticity field (vorticity), and velocity (U). For reference, the corresponding ssh and vorticity from the Aviso product (from satellite altimetry) are also included. map_small_30km.mat map_small_50km.mat Movies showing the maps and location of the data constraining it are included: maps_small_30km.m4v maps_small_50km.m4v ---------------- FULL OCEAN DEPTH CTD SECTION 7 deep hydrographic casts were done using the ship’s CTD system on 8-9 June 2019. These profiles are reported in the structure array 'ctd_section.mat', and plotted in 'ctd_section_S.jpg' ---------------- REFERENCES Bretherton, F.P., Davis, R., Fandry, C., 1976. A technique for objective analysis and design of oceanographic experiments. Deep-Sea Res. 23, 559–582. Centurioni, L.R., 2018. Drifter technology and impacts for sea surface temperature, sea- level pressure, and ocean circulation studies. In: Venkatesan, R., Tandon, A., D'Asaro, E., Atmanand, M.A. (Eds.), Observing the Oceans in Real Time. Springer Oceanography, Cham, Switzerland, pp. 37–58. https://doi.org/10.1007/978-3-319- 66493-4_3. Springer International Publishing AG. Ducet, N., P. L. Traon, and G. Reverdin, 2000: Global high- resolution mapping of ocean circulation from TOPEX/ Poseidon and ERS-1 and -2. J. Geophys. Res.,105, 19477– 19498 Freeland, H.J. Gould, W. J. 1976, Objective analysis of meso-scale ocean circulation features. Deep-Sea Res. 23, 915–923