1. GOAL OF THIS WORK ■ To investigate larval transport in “idealized” simulations ● To describe long term & short term dispersal kernels ● Four scenarios considered ▷ Strong or weak upwelling ▷ Northern or southern California ■ To develop modeling to establish short time kernels from available data sets

2. IDEALIZED SIMULATIONS ■ Idealized is state that shows 1) statistical stationarity 2) statistical homogeneity in alongshore 3) physically reasonable coastal current ■ Make particle tracking easier ■ No such simulation in literature ● Need to construct our own

3. OBJECTIVE OF THIS TALK ■ To show progress in simulation construction ● Focus on summer northern California ● Hard to satisfy three “idealized” conditions ● Still some problems in simulations

4. ROADMAP ■ Four things to be modeled 1) Numerical domain 2) Boundary conditions 3) Initial conditions 4) Forcings ■ Show obtained simulation fields & trajectories ■ Research plan to obtain kernel

5. 1) NUMERICAL DOMAIN ■ 64 x 64 x 32 grid points 512 km x 512 kmDepth: 20 m -- 500 m

6. 2) BOUNDARY CONDITIONS Periodic Free-slip wall Nudging & sponge layer Wind stress Open B.C.'s

7. 2) BOUNDARY CONDITIONS ■ O pen B.C.'s ● Outflow: radiation ▷ Extrapolates boundary values from interior values ● Inflow: nudging ▷ Forces boundary values to reference values ● Sponge & nudging layer ▷ Remove numerical difficulty

8. 3) INITIAL CONDITIONS ■ Determined using CALCOFI Atlas ● Velocity: geostrophic velocity ▷ No motion at 500db (500m) ● Temperature ▷ Consistent with given density field ● Sea level ▷ Dynamic height with zero mean

9. 4) FORCINGS ■ Two external forces: wind stress & pressure gradient ■ Wind stress: Modeled with Gaussian random process whose statistics taken from NBDC archive ○ Cross-shore: 0-m/s mean, 1.2-m/s std, 1-hour corr. ○ Alongshore: -5.6-m/s mean, 4.6-m/s std, 2-hour corr.

10. 4) FORCINGS ■ Pressure gradient: imposed as external force ● Periodic domain cannot develop pressure difference at north/south boundaries ● Computed from dynamic height difference between Pt. Arena & Pt. Conception

11. COMPUTATION ■ Two year simulation with 30-minute time stepping ● Using ICESS cluster ▷ Took 6 hours using 2 CPU's ▷ Eventually using 12 CPU's ■ Lagrangian particles: ● Released after fields are fully developed ● Released every day at fixed location

12. RESULTS: TEMPERATURE

14. RESULTS: ALONGSHORE VELOCITY

15. RESULTS: SEA LEVEL

16. RESULTS: KINETIC ENERGY

17. RESULTS: PARTICLE TRAJECTORIES

18. PLAN TO OBTAIN KERNEL ■ Describe kernel in idealized simulations ● Track “settlers” & sort them by PLD ▷ Issue: what is “settlement”? ● Question: how do they look? ▷ Long term? Short term? ■ Model short term kernel ● From available data set

19. PLAN TO OBTAIN KERNEL ■ Detect particle correlation time & length ● Say, particles released within 20 hours at same source go to same destination ● Say, particles released at sources separated 2 km or less at same time go to same destination ■ Release many particles separated by 2 km every 20 hours ■ Observe when kernel becomes Gaussian ● Possibly a month, or possibly over years

20. SUMMARY ■ “Idealized” simulations are under development ● Little too excited ● But, shows reasonable turbulence structures ● Will be done shortly ■ Dispersal kernel will be provided soon (hopefully) ■ Adding complexity ● Inhomegeneity, behavior, etc