napredne metode u istraživanju dinamike jadrana
TRANSCRIPT
Advanced Modeling & Observations
of Dynamic in the Adriatic Sea
Dr.sc. Ivica Janeković,
IRB, Zagreb
Outline
Intro
Adriatic Sea
Observing Adria
New Methods
Empirical
Theoretical
Combination
Examples
Physical oceanography
Remote sensing – Sea Surface
– Active and passive sensors, ASAR, AATSR
– Repeat cycle / spatial resolution
– HF Radar
Fixed stations/platforms – in situ
– ADCP, CTD, XBT, samples
– Profiler, glider, drifter…
Theory
– Modelling – approximation
– Data Assimilation – Combination
Chavanne, C., I. Janeković, P. Flament, P.-M. Poulain, M. Kuzmić, and K.-W. Gurgel (2007), Tidal currents in the northwestern Adriatic: High-frequency radio observations and numerical model predictions, J. Geophys. Res., 112, C03S21, doi:10.1029/2006JC003523.
HF radars Goro Ravenna Pesaro
ADCP database
netCDF?
opendap?
Thredds?
ownership?
Center for Marine Research
Ruđer Bošković Institute (since 1891)
Oceanographic Data Base (since 1972)
40 years of data time series
monthly sampling, 5-6 depths
3 mayor profiles: Rovinj - Po delta
North profile
Western Istrian coast - Kvarner
Chlorophyl a Chl a
Temperature, Salinity T, S
Inorganic Nutrients NO2, NO3, NH4, PO4, Si(OH)4
Dissolved Oxygen O2
Cyanobacteria
Heterotrophic bacteria
Nanoflagelates
Picoeukariotes
Primary production
Bacterial production TdR, Leu
Modelling
Approximation of real state, numerics, resolution, …
Forecast of future state, new knowledge
Virtual laboratory
Global -> Local Nesting (MyOcean boundarys)
Data Assimilation:
Combining observation space with model -> right way
Give answers where and how to observe
Sensitivity analysis
Janeković, I., and B. S. Powell (2012), Analysis of imposing tidal dynamics to nested numerical models, Cont. Shelf Res., 34, 30–40, doi:10.1016/j.csr.2011.11.017.
Zagreb, HAZU Zagreb, HAZU
Zagreb, HAZU Zagreb, HAZU
Nesting 2km -> 500m
Stong bura wind case
Data Assimilation
In a start they were primitive, OI,...
Direct consequence of met. development
New, advanced 3D, 4D-Var
ROMS 4D-Var the most advanced OM
Additional benefits:
Combination of model and obs, using evolving errors in time
Optimal observation setup
Sensibility of dynamics w/r to observations, obs sens.
Predictability, persistence, non-linearity of the system
Corrections to the initial, boundary, forcing
Powell, B. S., I. Janeković, G. S. Carter, and M. A. Merrifield (2012), Sensitivity of internal tide generation in Hawaii, Geophys. Res. Lett., 39,L10606, doi:10.1029/2012GL051724.
ROMS 4D-Var demystified
Time evolving error cov. matrices (R, D)
Assimilation of data at exact time and space (4D)
Variational methods for minimizing “cost” function
J = Jo + J
b , δz control vector (assembled of IC, BC, F)
Jo = ½ (G*δz -d)T R-1 (G*δz -d)
Jb =½ (δzT D-1 δz)
∂J/∂δz = 0
δza = [ D-1
+ GT R-1 G ]-1 GT R-1 d
100*300*30*7*8 = 1,68 mil points / time step
Janeković, I., B. S. Powell, D. Matthews, M. A. McManus, and J. Sevadjian (2013), 4D-Var data assimilation in a nested, coastal ocean model: A Hawaiian case study, J. Geophys. Res. Oceans, 118, doi:10.1002/jgrc.20389.
Satellite SST, SLA HF radials, CTD, ADCP, Glider
Satellite SST CTD, ADCP
Janeković, I., B. S. Powell, D. Matthews, M. A. McManus, and J. Sevadjian (2013), 4D-Var data assimilation in a nested, coastal ocean model: A Hawaiian case study, J. Geophys. Res. Oceans, 118, doi:10.1002/jgrc.20389.
20 NLM
Perturbations
20 NLM realizations
20 TLM
Perturbations
CO
RE
LA
TIO
N
20 TLM realizations
Linearity of the Adriatic Sea?
Do we need near real time data?
Correlation btw 20 non-linear and linearized model ensembles
ZETA TEMP SALT EAST WEST
Days since start of simulation
30
5
1-1-2012 19-3-2011 25-6-2011 24-9-2011
15-2-2012 15-2-2012 15-2-2012 15-2-2012
39
30
1-1-2012 19-3-2011 25-6-2011 24-9-2011
15-2-2012 15-2-2012 15-2-2012 15-2-2012
TEMPERATURE
SALINITY
FREE SURFACE
Ocean interior (and Adriatic) is undersampled
Have to be careful where and what and how to measure
New techniques used to point ↑
Combination of obs and theory is win-win
Provide truth, correct model, produce new dyn. response
Extend information, explain dynamics
Point to the unresolved regions where to measure
Observation sensitivity and valuable contribution
Applied studies, more realistic, benefit
Discussion & Conclusion…