# Presentation: 083382

## Hurricane Model Transitions to Operations at NCEP/EMC

*2007 IHC Conference, New Orleans*
- Robert  Tuleya*, V. Tallapragada,_ _
- Y. Kwon, Q. Liu, W. O’Connor,
-  S. Gopalkrishnan*, and N. Surgi

** JHT sponsored*

## Project Goals and Emphasis 

- EMC aided the upgrade of the GFDL model through implementing improved physics packages... microphysics  already in WRF
- Establish baseline of skill for WRF development ...use of GFDL physics
- Transition of Hurricane model from GFDL to WRF
- Continued collaboration with URI and GFDL

## HWRF  Hurricane Forecast System

- WRF coupled model
- 1.NMM HWRF   2.POM   3. COUPLER

- NHC storm message
- Position domain

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

- Get OBS, Model Input
- initial & boundary conditions

- Ocean Initialization
- Initialize wake, loop currents & eddies

- Wrf si (used for topographical parameters)
- Wrf real:replace with interpolations from native model data

- storm analysis and data ingest
-    6hr 1st guess
-   vortex relocation
-   3DVAR gsi for both nests

- Next cycle

## 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 ****been**** linked to a complete hurricane forecast system ****with nesting integrated**

## The NMM-WRF Modeling Systemhttp://www.dtcenter.org/wrf-nmm/users/

- 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.

## 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.

##                 HWRF – GFDL 

| Grid configuration | 2-nests (coincident) | 3-nests(not coincident) |
| --- | --- | --- |
| Nesting | Force-feedback
 | Interaction thru intra-nest fluxes |
|  |  |  |
| Convective parameterization | SAS mom.mix. | SAS  mom.mix. |
| Explicit condensation | Ferrier | Ferrier |
| Boundary layer | GFS non-local | GFS non-local |
| Surface layer | GFDL ..(Moon et. al.) | GFDL ..(Moon et. al.) |
| Land surface model | GFDL slab | GFDL slab |
| Dissipative heating | Based on D-L Zhang | Based on M-Y tke 2.5 |
| Radiation | GFDL (cloud differences) | GFDL |

## Sensitivity of physics packages Surface exchanges.....collaboration with URI

- analytical

- HWRF model

- CH

- CH

- CD

- CD

- CH

- CH/CD

## Sensitivity of track to enthalpy exchange

- Katrina

- Wilma

- GFDL

- HWRF

## Sensitivity of track to enthalpy exchange (little difference)

## Sensitivity of intensity to enthalpy exchange

- magnitude

- bias

- HWRF Enthalpy difference

- GFDL

- GFDL

## HWRF sensitivity to radiation & clouds (not much difference)

- HWRF with/without
-        clouds

- Ivan

- Helene

## Sensitivity of clouds vs momentum mixing

- HWRF with strong momentum mixing

- HWRF with cloud differences (Helene)

## HWRF accomplishments

- Ran real-time parallel moveable nested 5-day runs for 2006 season (2-way interaction with GFS physics/GFDL&GFS initial conditions) in robust fashion
- Made changes to system to improve accuracy
- Fixed inconsistency of cumulus momentum mixing
- Transitioned from GFDL & GFS initial condition to vortex relocation with data assimilation
- Installed momentum and enthalpy exchange consistent with 2006 GFDL
- Installed preliminary version of ocean coupling together with URI
- HWRF system to run in binary and start-up from higher accuracy native GFS data

## Summary & Plans

- Upgrade, evaluate and tune physics ....surface layer, lsm, microphysics, ....radiation & clouds, lateral b.c.
- Continue parallel HWRF runs.... forecast/analysis cycle
- Compare with GFDL and other models
- Implement operational HWRF

##  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**

## 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**

##    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**

## 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 boundary layer physics, updated surface exchange,GFDL radiation and Ferrier microphysics
- POM Ocean coupled modeling system.

## NMM-WRF GRID MOTION

- The nesting procedure is Mass consistent and is currently two-way interactive.
- Parent domain is  ~750x750 at domain center 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. **