Comparison of the Equatorial Undercurrent at 08, 1408W from ADCP Measurements and LLC4320 High-Resolution Global Ocean General Circulation Model

Authors

• David Halpern, Scripps Institution of Oceanography
• Kate Q. Zhang, UCLA Joint Institute for Regional Earth System Science and Engineering
• Dimitris Menemenlis, San Jose State UniversityFollow

Publication Date

8-1-2026

Document Type

Article

Publication Title

Journal of Atmospheric and Oceanic Technology

Volume

43

Issue

8

DOI

10.1175/JTECH-D-25-0066.1

First Page

999

Last Page

1009

Abstract

We tested the capability of a high-resolution ocean general circulation model called LLC4320, with 2.3-km horizontal grid spacing at the equator, to replicate hourly measurements of currents recorded at 5-m depth intervals in the Pacific Equatorial Undercurrent (EUC) with an acoustic Doppler current profiler (ADCP) moored at 08, 1408W. The LLC4320 simulations of the mean and variability of the horizontal currents and the vertical shear above the depth of the EUC core speed were poor compared to ADCP observations. The LLC4320 EUC core speed was slower, deeper, and less variable than ADCP measurements. The ADCP and LLC4320 currents were captured, with varying degrees of agreement: (i) meridional current oscillations with approximate 19-day period, (ii) a Kelvin wave–like pulse, and (iii) EUC surfacing.

Keywords

Buoy observations, General circulation models, Model comparison, Model evaluation/ performance, Ocean, Ocean models

Comments

© Copyright 2026 AMS

Department

Moss Landing Marine Laboratories

Recommended Citation

David Halpern, Kate Q. Zhang, and Dimitris Menemenlis. "Comparison of the Equatorial Undercurrent at 08, 1408W from ADCP Measurements and LLC4320 High-Resolution Global Ocean General Circulation Model" Journal of Atmospheric and Oceanic Technology (2026): 999-1009. https://doi.org/10.1175/JTECH-D-25-0066.1