Predictability in the Straits of Florida: the role of eddies and coastal upwelling near Cuba
V. Kourafalou1, Y. Androulidakis1, HeeSook Kang1, M. Le Hénaff1,2
1University of Miami, Miami, FL 2NOAA/AOML, Miami, FL Methods and data
HINDCAST AND REAL-TIME FORECAST SYSTEMS • GoM-HYCOM 1/50 (Gulf of Mexico) • FKEYS-HYCOM 1/100 (Straits of Florida) OBSERVATIONAL DATA • AVISO satellite altimetry • Ocean Color (MODIS) → eddy detection and coastal upwelling • Drifter trajectories Motivation and goals
1. Understand the local dynamics (Straits) and its connection with basin (Gulf) dynamics 2. Improve predictability 3. Evaluate findings and models with observational data (satellite & in situ) 4. Investigate the contribution of local conditions (e.g. coastal upwelling) to the formation of anticyclonic eddies along Cuba 5. Estimate offshore transport of coastal waters in the Straits of Florida MODEL DOMAINS (hindcasts and forecasts) GoM-HYCOM FKEYS - HYCOM
FKEYS
Le Hénaff and Kourafalou, 2016 Kourafalou and Kang, 2012
MAIN PRODUCTS: • Real time 7-day forecasts of circulation, sea elevation, temperature, salinity • High resolution model archives (~1.8 km and ~900 m) • Applications: Oil spill and Larval transport FKEYS-HYCOMGoM 7--HYCOMday forecast 1/50 from – model Jan 17evaluation (initial) to Jan 24, 2018 https://coastalmodeling.rsmas.miami.edu/forecast/forecast-gulf-of-mexico-high- resolution/index.html
• The GoM-HYCOM 1/50 simulation adequately represents the interannual variations of the basin mean sea level
• The RMS Error with respect to Maps of Absolute Dynamic Topography (MADT) is lower than existing operational products (by 15-20%) FKEYS-HYCOM 7-dayFKEYS forecast-HYCOM from 1/100Jan 17 (initial) to Jan 24, 2018 http://coastalmodeling.rsmas.miami.edu/Models/View/FORECAST_SOUTH_FLORIDA_ AND_FLORIDA_STRAITS Sea Surface Height Surface Currents (zoom)
& Currents
activity Anticyclonic
Sea Surface Temperature
- The FKEYS-HYCOM 1/100 simulation represents typical
Cyclonic activity Cyclonic mesoscale activity of the FL Straits Focus on anticyclones and upwelling near Cuba
• The FKEYS-HYCOM 1/100 simulation adequately represents the anticyclonic eddies forming along the northern coast of Cuba: Cuba ANticyclones (CubANs) Cuba ANticyclones (CubANs)
AVISO altimetry fields
(Kourafalou et al., JGR 2017)
Two types of CubAN eddies: • Eddy inside the Loop Current (type A) • Eddy released from the Loop Current and advancing eastward (type B) • Both can observed simultaneously Interaction between CubANs and Loop Current/Florida Current
1st effect: Loop Current location and 2nd effect: Transport meandering of the Florida Current variability in the Straits
(Kourafalou et al., JGR 2017) (Androulidakis et al., In Review)
Example of two periods in 2010, when CubANs “B” reduced the eastward transport in the Straits Interaction between CubANs and Loop Current/Florida Current
AVISO+DRIFTER FKEYS MODEL
No CubAN Extended LC
CubAN formation LCE detachment
LCE detachment
FC shift to the North
LCE re-attachment
(Kourafalou et al., JGR 2017) Offshore transport of upwelled waters – CubAN effects
GoM MODEL SSH Aug 26- Sep 9, 2016 MODIS – Chl-a Aug 26
CAA
Aug. 26 Sept. 1st
MODIS – Chl-a
Sept. 5 Sept. 9 Sept. 5
CAA C
MODEL Relative Vorticity Sep 9
Sept. 9
- The GoM-HYCOM 1/50 simulation adequately represents the cyclonic eddy formed under upwelling conditions and observed by surface drifter Offshore transport of upwelled waters – CubAN effects
CubAN eddy (type “B”) and No CubAN eddies in the Coastal Upwelling Straits of Florida
- Testing one month with CubAN eddies against a month without CubAN eddies - Initial release of 100 particles over an area with upwelling + CubAN eddy, in July 2011 - Earlier entrainment of particles in the Atlantic area when CubANs are absent. Conclusions
• GoM and FKEYS models adequately simulate the regional and local dynamics over the Gulf of Mexico and the Straits of Florida • Observational data confirmed the validity of both systems • New circulation features in the Straits of Florida (Cuba ANticyclones, CubANs, along the northern Cuban coast) • Strong interaction between CubAN eddies and regional circulation (Loop Current and Florida Current): position and magnitude • Presence of CubANs → Lower eastward transport over the Straits of Florida by the Florida Current • Local conditions (coastal upwelling) play a role in the formation and evolution of CubAN eddies • CubAN eddies affect connectivity pathways and timing in the Straits of Florida → Implications in biology and in oil spill forecast in the Straits of Florida