JHT Project: Evaluation and Improvement of Ocean Model Parameterizations for NCEP Operations L. K. Shay, G. Halliwell and B. Jaimes MPO/RSMAS, Univ. of Miami AOML/PhOD

Outline: Cold and Warm Core Eddies -Ivan (04) Loop Current/Warm Core Eddy Interactions (deep OML) 1. Katrina and Rita (05) (Idealized Simulations) 2. Gustav and Ike (08) Preliminary Comparison to Navy/NOAA Models Using DWH T(z) Data (Assimilation Versus Non Assimilation) 2011 HFP with NOAA IFEX/ DOI BOEMRE/NSF Summary Recurrent Theme: 3-D Upper ocean observations are critical in understanding the response and interactions with atmosphere.

Ivan (2004) over the GOM SSH (cm) from HYCOM (from Halliwell et al., MWR, 2008). NRL SEED Mooring data provided by Bill Teague (NRL- Stennis) SST Analyses Northern Cyclone Southern Cyclone

HYbrid Coordinate Ocean Model (HYCOM) Hurricane Ivan Simulations 10 Sept-6 Oct 04 (Halliwell et al., 2011) Configuration: 0.04° Mercator grid, Gulf of Mexico domain No data assimilation performed Initial and boundary conditions from U.S. Navy HYCOM ocean nowcast-forecast system: Data assimilative ocean nowcast Navy Coupled Ocean Data Assimilation (NCODA) assimilation Atmospheric Forcing: Navy 27 km COAMPS atmospheric model Vector wind blended with higher resolution fields from HWIND Wind stress for HWIND calculated using Donelan cd

Hurricane Ivan Modeling Experiment Summary Model AttributeBaseline Experiment GOM1Alternate Experiments Horizontal resolution0.04° MercatorGOM2: 0.08° Mercator Vertical resolution26 layers, 4-8m in OMLGOM3: 21 layers, m in OML GOM4: 31 layers, 3-5m in OML Vertical mixingKPPGOM5: MY GOM6: GISS CDCD DonelanGOM7: Powell GOM8: Large and Pond GOM9: Large and Pond (capped) GOM10: Shay and Jacob C EL, C ES COARE3.0 algorithmGOM11: Kara et al. Atmospheric forcing27-km COAMPS+H*WINDGOM12: 27-km COAMPS only Outer modelNCODA GoM hindcastGOM13: Free GOM simulation Ocean Dynamics3-D Ocean PhysicsGOM14:1-D Column Models

Observed KPP (control) Mellor-Yamada GISS Vertical Mixing Conclusion: KPP mixing produces the most realistic shear response. Other two choices under- estimate entrainment, which reduces mixed layer deepening and SST cooling.

Drag Coeff. Parameterization Observed Powell et al. Donelan et al. (control) Large and Pond Conclusion: parameter- izations that yield coefficients between 2 x and 2.6 x at high wind speeds produce the most realistic shear response. Larger (smaller) coefficient Values increase (decrease) mixed layer deepening and SST cooling

Ivan Model Summary Ivan a clear example of negative feedback (wake cooling/mixing induced by strong winds and Cold Core Ring) as opposed to positive feedback over the Loop Current and Warm Core Rings. Relative to the NRL ocean measurements in Ivan: Simulated shear response is a stringent test of model performance – KPP mixing outperforms Mellor-Yamada and GISS – Drag coefficient parameterizations that yield values between 2.0 x and 2.6 x (e.g. Donelan et al.) outperform those that yield larger or smaller values – No need to use vertical resolution of < 10 m with KPP mixing – Same conclusions realized at other SEED moorings (not shown) Model evaluation must be extended to other storms and to differing ocean regions Katrina and Rita (05); Gustav and Ike (08); Frances (2004)

The 2005 Loop Current System experiment twice the radius of maximum winds Moorings CCE2 LC Seawater temperature and conductivity data from four airborne surveys. Mooring data: velocity, temperature, and conductivity at ~10 m intervals. CCE1 WCE For the first time, the ocean response to major hurricanes was simultaneously measured inside cyclonic and anticyclonic geostrophic features.

cluster-averaged temperature profiles (Hurricane Rita) Loop Current bulge:  T ~ -1 o C 26 o C CCE:  T ~ -4.5 o C TC-induced cooling in geostrophic eddies Jaimes and Shay, MWR, 2009

Model approach Isopycnic model (MICOM) to suppress spurious vertical mixing. Idealized, though very realistic quasi-geostrophic vortices. Turbulence closure for the oceanic mixed layer (OML) that considers wind erosion and vertical shear at the OML base and in the stratified ocean underneath. Constant wind stress fields from direct measurements during Katrina. WCE1 WCE2 CCE1 CCE2 Jaimes et al (JPO: in review)

47 isopycnic layers. Initial temperature and density fields from WP-3D data acquired after Katrina. High vertical resolution below the OML and over the thermocline (10 m, similar to vertical resolutions in MMS moorings). CCE WCE Observations Model Jaimes et al (JPO: in review) Model Characteristics Model Characteristics

OML cooling Jaimes et al (JPO: in review) Realistic OML cooling of less than 1.2 o C in WCEs, and of about 4 o C in CCEs. More intense OML cooling over more energetic WCEs and CCEs (right panels). More and less intense OML cooling over CCEs and WCEs, respectively, compared with quiescent background conditions. WCE1 CCE1 WCE2 CCE2

CCE1 CCE2 Stationary vortices (f- plane) Freely propagating vortices (β- plane) Quasi-geostrophic vortices transport the temperature anomaly caused by tropical cyclones, distorting the cold wake. Jaimes et al (JPO: in review) Black circles represent the initial position of the vortices.

Horizontal convergence of warm water under the storm’s eye. Wind erosion occurs over a warm, deep, and nearly homogeneous water column. Kinetic energy injected by the tropical cyclones is rapidly dispersed, which reduces vertical shears and mixing in the upper ocean. WCEs ΔT < -1 o C Upwelling of cold water under the storm’s eye. Wind erosion takes place over a a shallow OML and over a near-surface water column with sharp vertical thermal gradients. Kinetic energy injected by the storm is trapped in upper layers that increase vertical shears and mixing. High quality ocean observations are critically important for model evaluations (e.g., NOAA IFEX, BOEMRE summer) CCEs ΔT ~ -4 o C Katrina and Rita Model Summary Katrina and Rita Model Summary

T(z) Data Assimilation Into Models

Taylor Diagram for T(z) over All 9 Flights ( m)

NOAA WP-3D profiling over BOEMRE Moorings (NOAA IFEX, HFIP) Expendables deployed from P-3 and proposed moorings relative to the LC, WCE and CCE superposed on late Sept 05 altimetry derived 26 o C isotherm Depth (After Rita). Deliverables include: V, T, S profiles to m resolution. Surface winds (SFMR, GPS) provided by HRD. Atmospheric profiles of V, T and 5-m resolution.