Project Title and Principal Investigator(s)

1. Background Project Title and Principal Investigator(s) Scientific Objectives Field Experiment Requirements Tropical Cyclone Structure-2008 (TCS-08)ONR/NRL Funded Projects • A 7-10 degree band of the WPAC centered along 22N provides a region of high natural variability in ocean conditions and energy source for TC’s transiting the region. • This region of high ocean thermal structure variability gives rise to variable ocean response to TC winds, impacting air-sea flux computations and resulting TC intensity changes. • New ocean observing technology in the form of thermistor chain equipped air-deployed drift buoys, AXBTs, GPS sondes and SFMR surface wind measurements together with the advent of coupled ocean-TC models with advanced data assimilation schemes provide an unprecidented opportunity to diagnose TC intensity changes due to oceanic variability. Impact of Upper Ocean Thermal Structure on TC Intensity Change in WPAC during TCS-08 Peter G. Black (peter.black@nrlmry.navy.mil) P. Peter Niiler (pniiler@ucsd.edu) Naval Research Laboratory, Monterey, CA 93943 Scripps Institution for Oceanography, La Jolla, CA • Describe TC intensity and structure change resulting from the upper ocean heat content (OHC) variability ocean response. • Map vertical thermal structure of warm and cold eddies ahead of at least one TC transiting the ‘Southern Eddy Zone’ of WPAC. • Validate satellite altimeter estimates of Ocean Heat Content (OHC). • Provide a viable data set for initializing and validating coupled TC/upper ocean regional forecast models. • Time sequence of WC-130J flight patterns flown ahead of and within a mature TC over 3 days during transit of the ‘Southern Eddy Zone’ of WPAC. • Deployment of 24 drifting buoys and AXBTs in 3 deployments of 8 drifters 24-36 hrs (250-350 nm) in advance the TC. • Overflight of buoy arrays with AXBT and GPS sonde deployments during storm passage and again over the drifters 24 hr after storm passage.