*********************************
There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
*********************************
COLLEGE OF SCIENCES
SCHOOL OF EARTH AND ATMOSPHERIC SCIENCES
EAS Ph.D. Defense
Maria Mercedes Pozo Buil
November 3, 2017
9:00 AM
Earth and Atmospheric Sciences
Ford Environmental Science & Technology (ES&T)311 Ferst Drive, ES&TAtlanta, GA 30332-0340Web: eas.gatech.edu
ES&T
L1114
Title: Exploiting Subsurface Ocean Dynamicsfor Decadal Predictability in the Upwelling Systems of the Eastern North Pacific
Committee members: Dr.Emanuel Di Lorenzo (advisor), Dr.Annalisa Bracco,Dr.Taka Ito,Dr.Kim Cobb,Dr.Steven Bograd(external, fromNOAA)
Abstract:Given the strong recent interest in the decadal timescale variability and the potential for its predictability, it is critical to identify dynamics that carry inherent decadal-scale predictability. This work enhances our understanding and prediction capability of the subsurface signature of the decadal variability in the eastern North Pacific upwelling systems using reanalysis products and a set of eddy-resolving ocean model simulations.
We show that subsurface temperature anomalies propagated by mean advection along the North Pacific Current significantly contribute through mean upwelling to decadal changes of surface temperature in the Gulf of Alaska. We also show that this influence is comparable to the contribution associated with variations in atmospheric winds.
We find that subsurface anomalies in the core of the North Pacific Current propagate temperature, salinity, and oxygen signals downstream into the coastal California Current upwelling system, following the path of the mean gyre circulation with a time scale of 10 years. We suggest these propagation dynamics lead to potential predictability of ocean tracers, specifically oxygen and nutrients.
Using reanalysis products and a set of eddy-resolving ocean model simulations, we provide evidence that supports the proposed inherent decadal predictability associated with the propagation of subsurface anomalies. We quantify the predictability of impacts associated with the arrival of the subsurface anomalies in the California Current upwelling system. We find a region of strong deterministic, predictable variance in the core of the North Pacific Current and in the sub-polar gyre region. Finally, we propose a dynamical subsurface connection between the western and eastern boundary, with subsurface anomalies generating and propagating eastward from the Kuroshio-OyashioExtension region in the Western Pacific all the way to the California Current region in the Eastern Pacific.
