# Presentation: 482832

## JHT Project: Evaluation and Improvement of Ocean Model Parameterizations for NCEP Operations (Ivan)

- L. K.  Shay, G. Halliwell, J.Brewster, C. Lozano, W. Teague
- MPO, RSMAS, Univ. of Miami
- EMC-NCEP
- Oceanography Department, NRL-Stennis
**http://isotherm.rsmas.miami.edu/~nick**

##      JHT Project Objectives:

***Ivan*** an example of **negative feedback** (cold wake cooling and Cold Core Ring) as opposed to less negative** feedback ****(****Loop Current/Warm Core Rings)**
- By building on a previous JHT, specific objectives  are:
- _optimizing _spatial resolution that will permit the ocean model to run efficiently as possible without degrading the simulated response;
*improving *the initial background state provided to the ocean model;
***improving*** the representation of vertical and horizontal friction and mixing;
**generating **realistic high-resolution atmospheric forcing fields necessary to achieve these objectives; and
**Testing **differing formulations of the drag coefficient (cd).

##   MOTIVATION:

**  ****MOTIVATION:**
**Ivan (2004) over the  GOM SSH (cm) from HYCOM (from Halliwell et al., MWR, 2008).**
**SST Analyses**

**  **

**Northern Cyclone**

**Southern Cyclone**

## Ivan’s Track and Intensity Relative to OHC (left) NRL SEED Mooring Locations in Northern Gulf of Mexico Relative to Bottom Depth (Right) (Teague et al., JPO, 2007).

**14 ADCP moorings- Focus here in Array 9.**

##  NRL Mooring Specifics (Teague et al., JPO, 2007).Note ADCP provides absolute velocity (u,v,w)

| Array #
 | Lat
oN | Long
oW | Start
Date
2004 | End
Date
2004 | Δt
(hr) | Depth
Range
(m) | Δz
(m) | Bottom
Depth
(m) | Instrument
Type |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2 | 29.43 | 88.01 | 05/01 | 10/31 | 0.25 | 4-54 | 2 | 60 | TRBM |
| 8 | 29.14 | 88.11 | 05/03 | 11/07 | 1.0 | 42-492 | 10 | 518 | LR |
| 9 | 29.19 | 87.94 | 05/03 | 11/07 | 1.0 | 40-500 | 10 | 518 | LR |
| 14 | 29.20 | 87.65 | 05/05 | 11/07 | 1.0 | 42-502 | 10 | 1029 | LR |

## HYbrid Coordinate Ocean Model (HYCOM)Hurricane Ivan Simulations 10 Sept-6 Oct 04

- _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 Attribute | Baseline Experiment GOM1 | Alternate Experiments |
| --- | --- | --- |
| Horizontal resolution | 0.04° Mercator | GOM2: 0.08° Mercator |
| Vertical resolution | 26 layers, 4-8m in OML | GOM3: 21 layers, 7.5-15m in OML
GOM4: 31 layers, 3-5m in OML |
| Vertical mixing | KPP | GOM5: MY
GOM6: GISS |
| CD | Donelan | GOM7: Powell
GOM8: Large and Pond
GOM9: Large and Pond (capped)
GOM10: Shay and Jacob |
| CEL, CES | COARE3.0 algorithm | GOM11: Kara et al. |
| Atmospheric forcing | 27-km COAMPS+H*WIND | GOM12: 27-km COAMPS only |
| Outer model | NCODA GoM hindcast | GOM13: Free GOM simulation |
| Ocean Dynamics | 3-D Ocean Physics | GOM14:1-D Column Models |

## Intense Forcing (upper) and 

**Intense Forcing (upper) and **
**Relaxation Stages (lower) for NRL SEED moorings 7-14**
**7-10 Red ~500 m**
**11-14 Yellow~1000 m**
**(Teague et al. JPO, 2007).**

**  **

## M9 (1.5 Rmax) Observed and Near-Inertial Current Shear Response (Rmax= 32 km)

**                ****Normalized shear by 10****-2**** s****-1**** based on Isidore/Lili **

##                    RMS SST (oC) Differences                     

**  **

**                   ****RMS SST (****o****C) Differences****  ****                   **
**                  **

## Pre Ivan SST 

**Pre Ivan SST **
**Post-Ivan SST**
**Pre-Post Ivan**
**      ****Δ****SST**

**  **

**          ****TMI and KPP SST Comparisons**** **

## Observed/Simulated 

**Observed/Simulated **
**Current Response at M9 (1.5 Rmax)**
**from 7 Experiments**
**Halliwell et al., MWR, (2009)**
***Below cd using ocean response as a tracer in Shay and Jacob (2006)***

##                          Current Time Series Comparisons @ 1.5 Rmax                     

**                         ****Current Time Series Comparisons @ 1.5 R****max  ****                   **
**                ****U (east-west)                                V (north-south)**

## Taylor Diag., simulations vs. baseline:

**  **

**Taylor Diag., simulations vs. baseline:**
**SST; **
**v Current at M9 (1.5Rmax).**
**(Halliwell et al., MWR, 2009)**

## Taylor Diag., simulations vs. observations:

**  **

**Taylor Diag., simulations vs. observations:**
**SST; **
**v Current at M9 (1.5Rmax).**
**(Halliwell et al., MWR, 2009)                  **

##  Progress Summary and Blueprint For Future

***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. **
**SST modulated by warm and cold ocean features that have to be properly initialized in ocean models and mixing.**  Data assimilation schemes are essential!
_***Trifecta Katrina, Rita and Wilma is next.***_
- Temperatures and currents needed to assess mixing schemes and evaluate initialization schemes. Both Eulerian (AXCP, AXCTD, moorings) and Lagrangian (drifters, floats)  needed – _Targeted Obs in storm coordinates!_
- Working with MMS on 5-year Loop Current Dynamical Study, NOAA HFIP and NSF.

## Sampling Pattern: AXCTDs and Drifters relative to OHC and Rita’s track.

**Pre (15 Sep) and Post Rita (26 Sep) WCR/CCR/ LC OHC and 26****o****C isotherm depth.**
**Vertical structure from AXCTDs **
**(Jaimes and Shay, MWR, 2009a)**