Determining the depth and upwelling speed of the equatorial Ekman layer from surface drifter trajectories

Paldor, Nathan; De-Leon, Yair

doi:https://doi.org/10.5194/os-21-1461-2025

Articles | Volume 21, issue 4

https://doi.org/10.5194/os-21-1461-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/os-21-1461-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 4

Research article

|

22 Jul 2025

Research article |

| 22 Jul 2025

Determining the depth and upwelling speed of the equatorial Ekman layer from surface drifter trajectories

Nathan Paldor and Yair De-Leon

Data sets

Wind Stress, QuikSCAT SeaWinds, 0.125Â°, Global, Science Quality, 1999-2009 (3 Day) NOAA/CoastWatch https://catalog.data.gov/dataset/wind-stress-quikscat-seawinds-0-125a-global-science-quality-1999-2009-3-day

Global Drifter Program - 6 Hour Interpolated QC Drifter Data NOAA/AOM/GDP https://erddap.aoml.noaa.gov/gdp/erddap/tabledap/drifter_6hour_qc.html

Short summary

The study combines archived surface drifter trajectories along the Equator with a novel extension of Ekman's wind-driven theory to the equatorial β-plane in order to estimate the depth of the equatorial Ekman layer and the speed of upwelling into it. The analysis provides a direct estimate of the depth of the equatorial Ekman layer based on observed drifter trajectories and does not involve the 3D continuity equation, which is only used for estimating the upwelling speed.