# Presentation: 511665

## Hurricane Model Transitions to Operations at NCEP/EMC

*2008 IHC Conference, Charleston, SC*
- Robert  Tuleya*, V. Tallapragada,_ _
- Y. Kwon, Q. Liu, W. O’Connor,
- and N. Surgi

** JHT sponsored*

## Project Goals and Emphasis 

- Participate in the operational implementation of HWRF
- Establish baseline of skill for WRF development ...use of GFDL physics
- Upgrade HWRF system
- Continued collaboration with URI, Florida State, GFDL, and others

## HWRF  Hurricane Forecast System

- HWRF model
- Coupled with POM

- 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

## 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 (POM GFDL).

##                 HWRF – GFDL 

| Grid configuration | 2-nests (coincident) | 3-nests(not coincident) |
| --- | --- | --- |
| Nesting | Force-feedback
 |  Interaction thru intra-nest fluxes  |
| Ocean coupling | POM (atlantic only) | POM |
| 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 |

## Implementation of TPC post processing guidance

- Standard text files
- Low level wind swath
- Rainfall swath
- Additional hourly data

## HWRF wind swaths

- GABRIELLE

- DEAN

- 2 landfalls

- glancing blow

## HWRF rainfall swaths

- Humberto

- Noel

- Floods in Dominican Republic & Cuba

- Heavy rain at landfall

## Hourly track & intensity 

- Hourly model data

- Model atcf data

- Model variability may be important ?

## HWRF Track Skill

- Competitive with other guidance
- Better than GFDL & NGAPS
- GFS & UKMET quite good
- Few long lasting storms in 2007
- EPAC HWRF not as good

- HWRF

## HWRF Intensity Skill

- Competitive with other guidance
- Some improvement over GFDL at early times
- Not a good year for dynamic models after accounting for landfall
- EPAC intensity degraded-no ocean coupling

- HWRF

## Sporadic SLP noise

- Sea level pressure diagnostic
- Model or post processing ??
- Traced to grid movement

- Noise

## Nest movement

- Leading edge (data from coarse mesh)

- Trailing edge
- (part of parent data after movement )

-      NEST

- Topographic smoothing zone
-  (no mass adjust after smoothing)

- Potential for SLP noise

## Change in topography causes noise in sea level pressure

- Leading edge

- Nest movement

## Eliminate SLP Noise

- Modify topographic smoothing zone
- Adjust mass fields
- No more Noise !

##                                  SLP Noise in initial HWRF fields

-                                  SLP Noise in initial HWRF fields
-                                     Traced to 3dvar & mass adjustment

- noise

## Other problem issues

- Topographical differences between models
- Surface flux formulations & land surface modeling
- Wind-pressure relationship

## GABRIELLE 

- GABRIELLE

## HWRF with GFS physicssurface flux & Noah LSM

- Dean track

- Dean Intensity

- GFS

- GFDL

- HWRFs

- Operational HWRF

- HWRF with GFS sfc options

- Physics are important !!

## HWRF Accomplishments

- Successfully installed operational system for the 2007 tropical season which runs in robust, timely fashion
- HWRF competitive with best operational guidance.

- HWRF Plans

-   Upgrade physics and test ensembles
-  Implement new ocean model
-  Implement wave model

## 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**

## 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. **