# Presentation: 436154

##  Hurricane Model Transitions to Operations at NCEP/EMC2004 IHC Conference, Charleston, SC

**Robert  Tuleya, Weixing Shen, **
**S. Gopalkrishnan, N. Surgi, and H.Pan****  **** **

## Project Goals and Emphasis 

- Improve GFDL model for operational use
- Establish baseline of skill for WRF development
- EMC interested in upgrading the GFDL model through implementing GFS physics packages.
- 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*

## GFDL Improvements: e.g. Track Forecasts for Hurricane Michelle from 2001, 2002 and 2003 GFDL Forecast Systems

## JHT tasks at EMC/NCEP

- Implement NOAH Land Surface model
- Install and Implement bulk microphysics packages into the GFDL model (Ferrier scheme)
-  Develop proto-type Hurricane WRF

## Slide 5

## Impact of LSM on intensity & track

## Impact of LSM on Rainfall

## Rainfall Verification

- LSM better

- LSM better
-          worse

## Issues and plans for LSM

- Difference between LSM and slab model appear small in track, intensity & rainfall in most cases
- More cases required to test sensitivity to relatively small number of landfalls... use historical cases... back to 1995??
- Run in semi-operational mode with more frequency this upcoming 2004 season
- Implement duel ocean and lsm coupling
- Improve efficiency  ~10% computation overhead ??

## Install & test sensitivity of microphysics in GFDL model

- How to initiate GFDL vortex-spin up with microphysics??
- How to blend with convective parameterization??
- Compare Lin with Ferrier scheme in parallel mode this 2004 season..

## Slide 11

## Motivation for new grid-scale scheme in Eta/GFDL

**Rapid increase in grid resolution with time**
**Prior to Oct ’95  (80 km, 38 levels)****Oct ’95  (48 km, 38 levels)****Feb ’98  (32 km, 45 levels)****Sep ’00  (22 km, 50 levels)****Nov ’01  (12 km, 60 levels)**
**Limited computational resources for physics  ********  keep it efficient!!**

**Biases from forecasters of grid-scale precip starting too soon,  ****high bias in light precip areas**
**Development of ****spurious grid-scale precip maxima (“bulls eyes”)**** in 22-km run during summer of 2001; occurred often in 10-km testing**
**Complaints from NESDIS of overpredicting upper-level cloudiness**
**Update Eta to be more consistent w/ RUC microphysics**
**Spurious gravity-wave excitation due to episodic updates of T**

## Deriving hydrometeor species from total condensate

## Reduced high bias in light precipitation (areas 1, 2) and improved orographic precipitation (area 3)

**(0-60 h forecasts of accumulated precipitation in inches valid 12Z 28 Oct 2001)**

## Development of Hurricane WRF Prototype

- Use same dynamic core NMM for both tropics and extra-tropics at EMC
- GFS physics performed well in hurricane simulations...start with ~same physics
- Run parallel uniform resolution prototype this upcoming 2004 season
- Encourage interaction with university and government scientists

## WRF Software Architecture

- OMP

**WRF Software Architecture**

- Config
- Inquiry

- I/O API

- Config
- Module

- WRF Tile-callable
- Subroutines

- Solve

- Mediation Layer

- Model Layer

- Driver Layer

- DM comm

- Threads

- External Packages

- Package
- Independent

- Package
- Dependent

- Data formats,
- Parallel I/O

- Message
- Passing

- Driver

- Registry

**Notes:**
Driver layer: akin to a framework. 

## WRF Software

**Goals**
- Community Model
- Good performance
- Portable across a range of architectures
- Flexible, maintainable, understandable
- Facilitate code reuse
- Multiple dynamics/ physics options
- Run-time configurable
- Nested

**Aspects of Design**
- Single-source code
- Fortran90 modules, dynamic memory, structures, recursion
- Hierarchical software architecture
- Multi-level parallelism
- CASE: Registry
- Package-neutral APIs
- I/O, data formats
- Communication
- IKJ Storage Order

## EMC HWRF experimental design(preliminary experiments)

- NMM core
- Non-hydrostatic, normalized pressure vertical coordinate
- Rotated latitude-longitude ‘E’ grid
- Eta model physics

- 223x501x60
- 12km grid
- 20sec time step
- ~2 1⁄2 hr on 49 undedicated processors

## Some preliminary resultsIsabel

## Some preliminary resultsGFS vs GFDL vortex

## Other JHT Projects

- Compare & evaluate more unified land-sea masks for GFDL ... same mask for ocean, lsm, & atmosphere (with GFDL & URI)
- Upgrade other GFDL routines... e.g.    radiation, surface physics, etc.
- Convert physics packages into WRF framework & check their integrity

## My fishing pier at Willoughby, VA

## My lucky neighbors

## My unlucky neighbors

- My unlucky neighbors

## Falling trees not in GFDL or NOAH LSM!!

## Slide 26

## Slide 27

## Other features of NGCP01 scheme

**Algorithm discriminates between cloud ice and “snow” (precip ice)**
**No cloud ice if subsaturated (prevents too much sublimation)****or if T>0********C (melting) ******** only “snow” (precip ice) is present**
**N****s**** = 0.2****·N****i**** if at or above ice saturation T < -8********C, -3********C < T < 0********C****(N****i**** is number of cloud ice crystals, N****s**** is number of “snow”)**
**N****s**** = 0.1 ·N****i**** if at or above ice saturation **_**and**_** -8********C < T < -3********C**

**Variable rime density ******** assumes accreted liquid water fills holes of ice w/o changing volume ******** (Total growth)/(Depositional growth)**

**Efficient lookup tables store solutions for various moments (ventilation, accretion, mass, precipitation)**
**Composite of multiple velocity-diameter relationships**
**Increase in fall speed of rimed ice (B****ö****hm, 1989) **