# Presentation: 444577

## Local Area Modeling 

**Robert Rozumalski****NWS National Science and Training Resource Coordinator****NWS/OCWWS****Winter Weather Workshop****Boulder CO****24 July 2003**

## 
Reasons for (not) running a local area model (LAM)
Role and goals of the SOO STRC in local area modeling
SOO/STRC workstation Eta package
Computer resources 
Some guidance for running a LAM
SOO/STRC National Case Study Library

- Reasons for (not) running a local area model (LAM)
- Role and goals of the SOO STRC in local area modeling
- SOO/STRC workstation Eta package
- Computer resources
- Some guidance for running a LAM
- SOO/STRC National Case Study Library

- Tour of Talk

***LAMs in the WFOs***

## 
To provide real-time data at temporal and spatial scales not available from operational sources
For studying local forecast problems and historically significant weather events
To provide an alternative to the configuration and physics of operational systems
To develop and test new diagnostic forecast techniques
To help in the training of forecasters on NWP-related issues

***LAMs in the WFOs***

- Why run a local mesoscale model?

- To provide real-time data at temporal and spatial scales not available from operational sources
- For studying local forecast problems and historically significant weather events
- To provide an alternative to the configuration and physics of operational systems
- To develop and test new diagnostic forecast techniques
- To help in the training of forecasters on NWP-related issues

## 90km 104 grid

- 15km WS Eta

- Spatial Resolution

- 12h Total Precipitation (in)

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## Hourly MSLP and Potential Vorticity

- Temporal and Spatial Resolution

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## Hourly 10 m wind and MSLP

- Temporal Resolution

## 1h Total Precipitation

- Temporal Resolution

## Hourly Precipitation Type

- Temporal Resolution

## Storm Total Snowfall 

- Storm Total Snowfall

- Temporal Resolution

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## Kain Fritch

- Betts Miller Janic

- Model Physics

- 24h Total Precipitation (in)

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## Kain Fritch

- Betts Miller Janic

- New Fields

- 24h Total Snowfall (in)

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## 1900 UTC  20 September 2002

- Locally  Significant Weather Events

***LAMs in the WFOs***

## LAMs in the WFOs

- Cloud Base Vertical Mass Flux
- 1800 UTC 20 September 2002

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## 1800 UTC  29 December 1996

- Locally  Significant Weather Events

- SFC Winds and Gusts

- 3km MM5 6hr forecast

***LAMs in the WFOs***

## LAMs in the WFOs

- Historically  Significant Weather Events

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## 
Setting up and running a LAM is too much trouble
“Running a model requires more computer power than I can afford”
“I don’t have enough time to baby-sit the model to make sure everything runs correctly”
There is little or no support
The operational data are good enough

- Setting up and running a LAM is too much trouble
- “Running a model requires more computer power than I can afford”
- “I don’t have enough time to baby-sit the model to make sure everything runs correctly”
- There is little or no support
- The operational data are good enough

- Why *not to* run a mesoscale model

***LAMs in the WFOs***

## 
NWP model package development and support
Advice for purchasing workstations and compilers
Guidance and support for configuring and running models
Scientific support for research utilizing NWP systems, ingestion of data, dissemination of output
Promote a dialogue between forecast offices regarding local modeling studies

- NWP model package development and support
- Advice for purchasing workstations and compilers
- Guidance and support for configuring and running models
- Scientific support for research utilizing NWP systems, ingestion of data, dissemination of output
- Promote a dialogue between forecast offices regarding local modeling studies

- The role of the SOO STRC in local modeling at the WFOs is to provide:

***LAMs in the WFOs***

## 

To improve the knowledge and use of mesoscale models and issues at the local level
To advance the forecasting process through an improved understanding of  mesoscale processes and the use of non-traditional diagnostic tools
To increase participation within the WFOs in developing and executing NWP studies to examine local forecast problems		

- To improve the knowledge and use of mesoscale models and issues *at the local level*
- To advance the forecasting process through an improved understanding of  mesoscale processes and the use of *non-traditional diagnostic tools*
- To increase participation within the WFOs in developing and executing NWP studies to examine *local forecast problems**	**	*

- The goals of the STRC in supporting local modeling at the WFOs are:

***LAMs in the WFOs***

## Simple goal:  latent complexity

**	**The SOO/STRC version of NCEP’s workstation Eta package was been developed to encourage and facilitate the use of LAMs in the forecast offices

*NWP models need be complex, *
*running them should not*

**	**SOO/STRC Workstation Eta

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

## 
The WS Eta is a complete, full physics system, nearly identical to the operational model
Easy to set up, configure, and run
	    little or no modeling experience necessary
The code is VERY efficient
	~ 25-33% faster than MM5 on 1 CPU
	~ 90% performance gain going from 1 to 2 CPUs
The package is fully supported by the SOO STRC
Runs on both UNIX and LINUX platforms
Binaries are available if you do not have a compiler

- The WS Eta is a complete, full physics system, nearly identical to the operational model
- Easy to set up, configure, and run
*	**    **little or no modeling experience necessary*
- The code is VERY efficient
***	***~ 25-33% faster than MM5 on 1 CPU
- 	~ 90% performance gain going from 1 to 2 CPUs
- The package is *fully* supported by the SOO STRC
- Runs on both UNIX and LINUX platforms
- Binaries are available if you do not have a compiler

***LAMs in the WFOs***

**	**SOO/STRC Workstation Eta

## LAMs in the WFOs

- Package run at ~80-90 WFOs
*Also Brazil, Costa Rica, Egypt, France, Turkey, Italy, Israel, Canada, Texas, and others*
- Available on SOO/STRC ftp site
- Hydro/Non-Hydrostatic option
- Nesting Capability
- 14km high resolution SSTs over Great Lakes
- eta/sigma coordinate option
- KF/BMJ option
- NCEP Reanalysis grid support
- Support for 12-km AWIPS 218 tiles
- Full resolution BUFR files
- Support for shared multi-processor (SMP) platforms

- Version 3.1.f Currently Available

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## Coarse Mesh

**Coarse Mesh**

**Fine Mesh**

**One-way Nesting in the WS Eta**

## LAMs in the WFOs

- Different data sets for initial and boundary conditions
- Ingestion of local LAPS grids
- Updates surface physics scheme
- 1-hourly BC data from NCEP
- Additional functionality
- Some bugs fixed
- New bugs added
- Currently being run operationally at WFO MIA with local LAPS

- Version 3.1.g Available Soon

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## 12km operational Eta

- LAPS Inclusion

***LAMs in the WFOs***

- 3km WS Eta

- Valid 21Z 24 July 2003

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## LAMs in the WFOs

- Best Lifted Index
- Vertical mass flux at cloud base
- Snowfall
- Convective inhibition
- Precipitation type
- Freezing level
- Storm surface runoff
- Precipitable water
- Many, many more

- A subset of the available fields from the WS Eta:

***LAMs in the WFOs***

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## LAMs in the WFOs

***LAMs in the WFOs***

**	**SOO/STRC Workstation Eta

**Notes:**

Beta test version was released in Mid-January.

All SOOs are encouraged to participate in the beta-test and provide suggestions for improvement

Initial official distribution is anticipated in early February

## “How much computer power do I need?”

## SOO/STRC WS Eta Benchmarks
	All benchmarks are based on a 24hr forecast on a 55x91x45 domain with a 15km grid spacing and 30 second timestep

HP 9000/715/64MHz		–  256mb		– HPUX 10.20	~7h  56min
AMD 400 MHz K6		–  192mb		– RH 7.0		~3h  56min
AMD 700 MHz Athlon 	–  256mb		– RH 7.0		~1h   27 min
INTEL/933 MHz Xeon 	–  1gb  		– RH 6.2                   	~1h   20 min
INTEL/2x500 MHz PIII 	–  512mb 		– RH 7.01 		~1h  07 min
HP C3000/400 MHz		–  1gb 		– HPUX 10.20	~      45 min
INTEL/2x933 MHz Xeon 	–  1gb 		– RH 6.2		~      44 min
INTEL2x1500 MHz P4 	–  1gb 		– RH 7.1  		~      38 min
AMD2x1400+ Athlon 		–  1gb 		– Mandrake 8.1 	~      32 min
AMD2x1500+ Athlon		–  1gb 		– RH 7.1		~      30 min
INTEL/2x2200 MHz Xeon	- 1.5gb		– RH 8.0		~      23 min
AMD - 9 node Beowolf Cluster	- 1.5gb		– RH 7.3		~        5 min

***	****All benchmarks are based on a 24hr forecast on a 55x91x45 domain with a 15km grid spacing and 30 second timestep*
**HP 9000/715/64MHz****	****	****–  256mb****	****	****– HPUX 10.20****	****~7h  56min**
**AMD 400 MHz K6****	****	****–  192mb****	****	****– RH 7.0****	****	****~3h  56min**
**AMD 700 MHz Athlon ****	****–  256mb****	****	****– RH 7.0****	****	****~1h   27 min**
**INTEL/933 MHz Xeon ****	****–  1gb  ****	****	****– RH 6.2                   ****	****~1h   20 min**
**INTEL/2x500 MHz PIII ****	****–  512mb ****	****	****– RH 7.01 ****	****	****~1h  07 min**
**HP C3000/400 MHz****	****	****–  1gb ****	****	****– HPUX 10.20****	****~      45 min**
**INTEL/2x933 MHz Xeon ****	****–  1gb ****	****	****– RH 6.2****	****	****~      44 min**
**INTEL2x1500 MHz P4 ****	****–  1gb ****	****	****– RH 7.1  ****	****	****~      38 min**
**AMD2x1400+ Athlon ****	****	****–  1gb ****	****	****– Mandrake 8.1 ****	****~      32 min**
**AMD2x1500+ Athlon****	****	****–  1gb ****	****	****– RH 7.1****	****	****~      30 min**
**INTEL/2x2200 MHz Xeon****	****- 1.5gb****	****	****– RH 8.0****	****	****~      23 min**
**AMD - 9 node Beowolf Cluster****	****- 1.5gb****	****	****– RH 7.3****	****	****~        5 min**

***LAMs in the WFOs***

## AMD Athlon Workstation Costs

Dual (2) MP 2600+ CPUs
1026 MB PC2100 DDR SDRAM 
120Gb ATA-100 Disk Drive
16x10x40x12 DVD/CD-RW  
Video card, mouse, keyboard, etc.
LINUX Red Hat 8.0 pre-installed

Benchmark
Time: est. sub-20 min  Cost: ~ $1300 
(source http://www.swt.com)

**Dual (2) MP 2600+ CPUs**
**1026 MB PC2100 DDR SDRAM **
**120Gb ATA-100 Disk Drive**
**16x10x40x12 DVD/CD-RW  **
**Video card, mouse, keyboard, etc.**
**LINUX Red Hat 8.0 pre-installed**
**Benchmark**
**Time: est. sub-20 min  Cost: ~ $1300 **
**(source http://www.swt.com)**

**INTEL P4 Workstation Costs**
**Dual (2) Xeon 2660MHz CPUs**
**1024 MB PC2100 DDR SDRAM **
**120Gb 7200 RPM IDE Disk Drive**
**16x10x40x12 DVD/CD-RW  **
**Video card, mouse, keyboard, etc.**
**LINUX Red Hat 8.0 pre-installed**
**Benchmark**
**Time: est. ~20 min  Cost: ~ $2000 **
**(source http://www.swt.com)**

- SOO/STRC WS Eta Hardware Requirements

***LAMs in the WFOs***

## On-line 7-day archive of all 4 Eta model runs on non-operational 221, 212, and 104 grids, and soon the 12km tiles
 Grib Archive since March 2000
Archive of operational Eta BUFR files began August 2001
 SST and snow cover data for WS Eta initialization.
 Available from the data/archive/grib directory on the SOO/STRC ftp server
Contact SOO STRC for earlier data
SOO/STRC 7-day archive of real-time AWIPS data
Reanalysis data available 1949 - present

-  Grib Archive since March 2000
- Archive of operational Eta BUFR files began August 2001
-  SST and snow cover data for WS Eta initialization.
-  Available from the data/archive/grib directory on the SOO/STRC ftp server
- Contact SOO STRC for earlier data
- SOO/STRC 7-day archive of real-time AWIPS data
- Reanalysis data available 1949 - present

- SOO/STRC Data Archive	High Resolution model data available for local studies

***SOO/STRC Data Support***

## Guidance and suggestions for running a mesoscale model at your local office*

**A little science*

## Model execution time (real-time forecasts)
Domain size
Horizontal resolution
Vertical resolution
Grid navigation
Resolution of initialization dataset
Phenomena of interest

- Domain size
- Horizontal resolution
- Vertical resolution
- Grid navigation
- Resolution of initialization dataset
- Phenomena of interest

- What to consider when setting up a LAM

***LAMs in the WFOs***

## LAMs in the WFOs

- The most important factor to consider when setting up a real-time forecast system. Less so for local modeling studies
- A forecast that is not timely is useless to forecasters
- However, a LAM forecast without skill is potentially more harmful than no forecast at all
- A timely, skillful forecast will require both          computational power and a wisely configured model

***LAMs in the WFOs***

##  	The influence of boundary conditions
   Model execution time
 	Development of computational grid-scale forcing
 	Forecast skill and value

-    Model execution time
-  	Development of computational grid-scale forcing
-  	Forecast skill and value

-  Choice of computational domain will impact:

- Computational Domain

***Do not sacrifice domain size for resolution!***

***LAMs in the WFOs***

##  	Errors in interpolation from external grid
 	Temporal aliasing of information
 	Inability to feedback information to larger scale
  An incompatibility between physical-process parameterizations 

-  	Usually provided by coarser model run
- Operational Eta or AVN
- Reanalysis data
- Previous WS Eta Model run
-  	Act to constrain numerical solution – *unlike global models*
-  	Influence on forecast is somewhat controllable

-  LBCs

-  	Errors in interpolation from external grid
-  	Temporal aliasing of information
-  	Inability to feedback information to larger scale
-   An incompatibility between physical-process parameterizations

-  LBCs can degrade a forecast through

-  Errors propagate via advection and inertial gravity modes

***LAMs in the WFOs***

-  Operational Eta uses the GFS forecast

## Domain 1

- Region
- of interest

- Domain 2

- Lateral Boundary Conditions and You

## WorkStation Eta 32 km Domain

**89x147**

**45x75**

**37x61**

**107 x 177**

**WorkStation Eta 32 km Domain**

**79x133**

**25x41**

**71x117**

**63x105**

**71x117**

## 17x29

**17x29**

**4 min**

**8 min**

**20 min**

**35 min**

**57 min**

**1h 15 min**

**2h 16 min**

**2h 50 min**

**3h 28 min**

## LAMs in the WFOs

***RMSD Vs Distance***

**0.00**

**0.10**

**0.20**

**0.30**

**0.40**

**0.50**

**0.60**

**0.70**

**0**

**50**

**100**

**150**

***Distance in Grid Points from Lateral Boundary***

***Root Mean Square Difference***

**89x147**

**45x75**

**37x61**

**79x133**

**25x41**

**71x117**

**17x29**

- 32km grid, 45 levels, 24hr
- 72s timestep
- 32km, 221 grid initialization

**21x35**

**63x105**

**107x177**

**101x167**

***LAMs in the WFOs***

## LAMs in the WFOs

- Region
- of interest

- Upstream flow

- Shift model domain in the direction of flow to reduce BC influences

***LAMs in the WFOs***

## LAMs in the WFOs

- The scale of a given atmospheric phenomenon is proportional to its forcing
-  The ability to simulate a given response will depend upon either:
- The particular forcing mechanism being fully resolved in the forecast initial state
- The ability of the model to develop the forcing during integration
***The scale contraction processes take time!***

***LAMs in the WFOs***

##   Topography is a very strong forcing mechanism
Well-known and well-resolved
Knowledge of large-scale flow may only be necessary to generate high-value forecasts
  Other non-transient (0-48 hrs) forcing mechanisms include
Land/water interfaces
Strong soil moisture gradients
Surface roughness gradients
Sharp transitions in surface albedo (sea/ice, snow, etc.)
Gradients in water temperature

** **** **Topography is a very strong forcing mechanism
- Well-known and well-resolved
- Knowledge of large-scale flow may only be necessary to generate high-value forecasts
** **** **Other non-transient (0-48 hrs) forcing mechanisms include
- Land/water interfaces
- Strong soil moisture gradients
- Surface roughness gradients
- Sharp transitions in surface albedo (sea/ice, snow, etc.)
- Gradients in water temperature

***LAMs in the WFOs***

## Terrain Height (m)

- Which model terrain will produce a better forecast?

## 72 hour Total Snowfall (in) valid 12 UTC 20 March 2003

- 2km NH run

- 50km run

- Run time 20 minutes

- Run time 37 hours

## LAMs in the WFOs

***LAMs in the WFOs***

- In local area modeling, do not assume that a model initialized closer to a verification time will always provide a better forecast
- Critical, small-scale phenomena may require time (> 6hours) to develop during model integration
- The “spin-up” of precipitation is an example of this process

*Non-local model forcing** *

## First determine the the areal coverage of your computational domain
Larger domain needed during the cool season
Increase size for longer period forecasts
Move the domain upstream of your region of interest
DO NOT locate lateral boundaries along regions of strong surface forcing such as complex terrain

Determine how much time you have for each run

Run some experiments to establish the allowable resolution
It may be > 10km – that is OK!
More resolution if you have strong local forcing

- Larger domain needed during the cool season
- Increase size for longer period forecasts
- Move the domain upstream of your region of interest
- DO NOT locate lateral boundaries along regions of strong surface forcing such as complex terrain
- Determine how much time you have for each run
- Run some experiments to establish the allowable resolution
- It may be > 10km – that is OK!
- More resolution if you have strong local forcing

- When setting up your LAM for real-time forecasting

***LAMs in the WFOs***

## Sub 10 km grid spacing does not necessitate NH
Non-Hydrostatic (NH) dynamics are computationally expensive
May not significantly impact forecast

If the phenomenon of interest is locally forced, you may sacrifice areal coverage for model resolution
Increasing the resolution at the expense of domain size may improve the forecast value

Otherwise, it is more important to provide a larger computational domain

- Non-Hydrostatic (NH) dynamics are computationally expensive
- May not significantly impact forecast
- If the phenomenon of interest is locally forced, you may sacrifice areal coverage for model resolution
- Increasing the resolution at the expense of domain size may improve the forecast value
- Otherwise, it is more important to provide a larger computational domain

- When setting up your LAM for real-time forecasting

***LAMs in the WFOs***

## Slide 50

## The SOO/STRC Case Study Library will serve as the on-line repository for operational data and support documentation for use in local training efforts utilizing WES, D2D, and D3D.

- Trainers will be able to select from a collection of peer-reviewed case modules identified by their educational objectives and organized to allow for easy identification so that offices can best meet their particular training needs.

## The CLS will provide resources for training in a variety of areas, including:

- Warning decision-making
- Forecasting techniques
- The use of operational forecasting tools
- The use of operational data types
- Application of scientific principles
- Experience with specific weather phenomena
- Data for case study research projects

## Slide 53

## Slide 54

## 
Reasons for (not) running a local area model (LAM)
Role and goals of the SOO STRC in local area modeling
SOO/STRC workstation Eta package
Necessary computer resources
Some guidance for running a LAM
SOO/STRC National Case Study Library

- Reasons for (not) running a local area model (LAM)
- Role and goals of the SOO STRC in local area modeling
- SOO/STRC workstation Eta package
- Necessary computer resources
- Some guidance for running a LAM
- SOO/STRC National Case Study Library

- Summary of Talk

***LAMs in the WFOs***

## Thank You 

***LAMs in the WFOs***