Validation of alternating zonal jets detected in satellite altimetry using in situ observations

University Of Hawaii, Honolulu

Investigators

Abstract

In this study, a researcher at the University of Hawaii will examine the observational evidence for alternating zonal jets detected recently in the sea level measured by satellite altimeter. He will evaluate the distribution of steady and time-varying jets by filtering altimetric sea level datasets and compare them with concurrent in situ observations. Surface and deep (2000m) currents will be derived from trajectories of surface drifters and Argo floats, respectively. Anomalies of geostrophic velocity at intermediate depth will be assessed from the tilt of isotherms along repeat XBT lines coherent with the signal in the sea level. ADCP, mooring current meters and CTD profiles will be used to enhance the dataset and to justify assumptions on vertical structure and spatiotemporal statistic of the velocity adopted in his techniques. Every method will be tested using the OFES model output to estimate its efficiency and accuracy. The work will be carried out in the regions of the open ocean free of energetic baroclinic currents, such as western boundary currents and their extensions of the Antarctic Circumpolar Current. The research will begin with the analysis of stationary quasi-zonal jets in the eastern North Pacific and will expand to other basins. Analyses of time-varying jets will include the cases of steady wave-like meridional phase propagation and stochastic jets, both supported by altimeter and OFES data. The results gathered from this work will validate satellite altimetry, which is important for describing the dynamical state of the ocean. It will also serve as the basis for the next step: monitoring jets, understanding their dynamics and connection to geophysical turbulence. In addition to the intellectual merit of the work, this research will train a Postdoctoral Associate to work with various observation data and numerical models. Results will be disseminated through peer-reviewed publications, national and international meetings, and through a webpage that will be established at the IPRC.