# Presentation: 083381

## Hurricane Model Transitions to Operations at NCEP/EMC

*2006 IHC Conference, Mobile, AL*
- Robert  Tuleya, S. Gopalkrishnan,
- Weixing Shen, N. Surgi, and H.Pan

*JHT sponsored*

## Project Goals and Emphasis 

- EMC interested in upgrading the GFDL model through implementing improved physics packages... microphysics & LSM already in WRF
- Establish baseline of skill for WRF development ...use of GFDL physics
- Begin transition of Hurricane model from GFDL to WRF
*EMC, GFDL and URI collaborate and rely on one another for their respective areas of expertise*

## Noah LSM in GFDL model

- 2005 season tracks

- 1998-2003 rainfall

##  Dramatic improvement in tropical cyclone track forecasts have occurred through advancements in high quality observations, high speed computers and improvements in dynamical models. Similar advancement now need to be made for tropical cyclone intensity, structure and rainfall prediction. Can these advancements be made with advanced non-hydrostatic models while achieving track and intensity skill comparable to GFDL??

**CLIPER**

**GFS**

**       ****TPC**

**GFDL**

##       Hurricane Forecast System

- Storm information

- Model integration

- Model hurricane output products

-       Hurricane Forecast System

- Wrf si
- Wrf real
- Wrf model

- NHC storm message
- Position domain

- Synoptic fields for many variables
- Create file for track, intensity, etc

## NMM- HWRF: The Hurricane Model

- Real cases:
- Standard
- Initialization
- (WRFSI/NMMSI)

**./Registry  ./inc**
**./Main**

- NMM-WRFPOST

**./phys**
**./frame**
**./share **
**./external **

**./dyn_nmm***

**WRF2.0**

*******This WRF core has to be linked to a complete hurricane forecast system**

## The GFDL Modeling System

- Regional-Scale, Moving Nest, Atmospheric  Modeling System.
- Hydrostatic system of equations formulated on a latitude-longitude, Arakawa A-grid and normalized pressure (sigma_p) coordinate system.
- Advanced initialization that uses GFS analysis, yet an improved and more realistic storm vortex that blends in well with the large scale environment.
- Uses SAS convection scheme, GFS surface, boundary layer physics, GFDL radiation and simple rain removal for grid scale precipitation.
- Ocean coupled modeling system.

## The NMM-WRF Modeling System

- Regional-Scale, Moving Nest, Atmospheric  Modeling System.
- Non-Hydrostatic system of equations formulated on a rotated latitude-longitude, Arakawa E-grid and a vertical, pressure hybrid (sigma_p-P) coordinate.
- Advanced HWRF,3D Variational analysis that includes vortex reallocation and adjustment to actual storm intensity.
- Uses SAS convection scheme, GFS/GFDL surface, boundary layer physics, GFDL/GFS radiation and Ferrier Microphysical Scheme.
- Ocean coupled modeling system.

## Some Numerical Details

- Time stepping method
- 	fast waves:  forward-backward
-    	vertically propagating sound waves:  implicit
- Advection:
-          horizontal:  Adams-Bashforth for U,V and T  (and Coriolis)
-          vertical:   Crank-Nicholson for U,V and T
-          forward, flux-corrected for q and water species
- Horizontal diffusion
-      forward, 2nd order “Smagorinsky-type”
- _[http://www.mmm.ucar.edu/mm5/workshop/ws04/Session7/Janjic.Zavisa.pdf](slide9.xml)_

## Salient Features: Telescopic E-Grid 

- All interpolations are done on a rotated lat-lon, E-grid with the reference lat-lon located at the centre of the parent domain.
-  Consequently the nested domain can be freely moved anywhere within the grid points of the parent domain, yet the nested domain lat-lon lines will coincide with the lat-lon  lines of the parent domain at integral parent-to-nest ratio.
- This coincidence of grid points between the parent and nested domain eliminates the need for more complex, generalized remapping calculations in the WRF Advanced Software Framework and is expected to aid better distributed memory performance, and portability of the modeling system.

## NMM-WRF GRID MOTION

- The nesting procedure is Mass consistent and is currently two-way interactive.
- Parent domain is about 600x600 at about 27 km resolution and the moving nest is about 60x60 at about 9 km resolution.
- The nest is "set to sail" on the parent domain using a simple criterion based on variations in dynamic pressure. The so called “stagnation point” was chosen to be the center of the storm (Gopalakrishnan et al 2002, MWR.)

## Test Cases with NMM grid motion

** ******** ****For configuration provided earlier, it takes about 55 minutes of run time (excludes wrfsi and real).** **.** **for 5 days of forecast  using 72 processors in our IBM cluster. **

## Sensitivity of physics packages Surface exchanges.....Ground temperatures

## Slide 14

## HWRF accomplishments

- Ran real-time parallel moveable nested 5-day runs for 2005 season (1-way interaction with GFS physics/GFDL&GFS initial conditions) in robust fashion
- Added moveable 2-way nested grid option
- Integrated nested files into HWRF post
- Added GFDL surface physics & ground slab
- Reconfigured GFS physics to conform to GFDL standards
- In 2004, ran 4 days with uniform mesh using GFS initial conditions and with NMM standard physics

##    Air sea fluxes:  wave drag,   enthalpy (sea spray)        

**    ****08                  09**                10                 11                     12

**  ****Implement    advance (reflectivity)       **
**  **

**Mesoscale Data Assimilation for Hurricane Core**

**  **

** **

**  **

**          ****Advancing  HURRICANE WRF System**

- Atm. Model  physics and resolution upgrades (continuous)

**   ****Air sea fluxes:  wave drag,   enthalpy (sea spray)        **
**     ****Microphysics **

**Incr. resolution**
**   ****(4km/>64L?)   **

** **

**Waves:  moving nest     Multi-scale imp.                  Highest-Res coast                           Ocean:  4km.    - continuous upgrades in  ODAS,  model res. **

**A4DDA**

## Summary & Plans

- Upgrade and evaluate physics....surface layer, lsm, microphysics, radiation
- Continue parallel HWRF runs.... forecast/analysis cycle ....initiate moveable, nested HWRF
- Compare with GFDL and other models

## HWRF 

**GFDL**

**    ****02-03**                **03-04           05               06                     07**

** **
** ****Begin Physics Upgrades**

-       **Mesoscale Data Assimilation for Hurricane Core**

**  **

**Prelim. Test                        HWRF physics **

-              **HWRF**
**             ****T&E**

**HWRF**

**  ****Operational**
-   (9km/42?L)

**      ****GFDL frozen**
**   ****HWRF T&E**

**          ****TRANSITIONING TO HURRICANE WRF**

**Begin R&D**

**HWRF **

**Continue     upgrades**