CALPUFF: Status and Up

Tyler Fox

9th Conference on Air Quality Mode

October 9, 2008
CALPUFF History

• CALPUFF modeling system:

– CALPUFF, a non-steady-state Lagrangian puff model– CALMET, a diagnostic 3-D wind field model

• CALPUFF was promulgated April 2003 as EPA’

model for long-range transport (LRT) application50 km, primarily for Class I increments

• CALPUFF developer (Earth Tech) arranged to m

control of code development and distribution and copyrighted code

• CALPUFF also identified in Appendix W for nea

applications involving “complex winds” on a casebasis (more on this later)

• CALPUFF also used for Class I AQRV analyses

Appendix W purview
Scorecard of CALPUFF 

Versions

- 5.7 April 2003 (promulgated version- 5.711a July 2004 (previous regulatory)- 5.711b December 2005- 5.754 February 2006 (original VISTAS- 5.756 August 2006 (latest VISTAS)- 5.8 June 2007 (current regulatory- 6.112 April 2006 (MMS) 

April, 2003 July, 2004 Dec., 2005

Feb., 2006

April, 2006 

5.7 5.711a 5.711b

5.754

6.112 
FEDs Discussions on CALPU

Spring 2006

• Reason: Earth Tech sells CALPUFF rights to T

2006) and EPA experiences difficulties in assesupdating to VISTAS version 5.754

• Representatives from Federal Agencies discuss

current situation with CALPUFF (status and reguupdates)

– EPA– FLM– MMS

• Discussed the following issues:

– lack of adequate documentation– responsiveness to issues by developer– need for funding to address any issues from Federal c

despite regulatory classification of the model
EPA contacts TRC:

June 30, 2006

• CALPUFF must meet Appendix W 

requirements for regulatory models, Section 3.1.1(b)-(d):

– *.exe to run on a common platform– current model documentation – input/output test data w/model– users can operate model from available 

documentation

– documentation must include compariso

w/tracer data

– model/code cannot be proprietary
TRC to EPA response:

July 11, 2006

• TRC provides copy of Use Agreeme• States that ... “Permission to modify 

Fortran computer codes is granted tusers with the provision that modifieversions of the model codes must be provided promptly to TRC, along witappropriate written documentation ainstructions for use”
TRC to EPA response:

July 11, 2006

• Use Agreement also states...

“It is the user's responsibility to dete

if the CALPUFF modeling system is appropriate for any particular applicaand the user assumes all responsibiand liability for its use.”
Analysis

Tool

Sources

Meteorology

Terrain

Differences

?

Reso

BETABASE

CALPUFF Update Too
CALPUFF Regulatory Upda

Version 5.7 to 5.711a

• Model Change Bulletin-A provided 

description of changes

– Only minor changes in coding

• Application of Update Tool showed 

minimal differences/impacts on concentrations

– Clearly attributed differences to bug fix

• Approved 5.711a - June 15, 2006
CALPUFF Regulatory Upd

• Began update process with v5.754 in Jun

2006

• Engaged with TRC in discussions to unde

5.711a vs. 5.754 differences

• August 15, 2006—Received e-mail from T

indicating a new VISTAS v5.756 would breleased

• OAQPS decided to focus on update for n

VISTAS v5.756

– newest features, latest corrections, etc. for us

community (including MMS updates for over 
CALPUFF Regulatory Upda

5.711a -> 5.756

• Found large ‘unresolved’ differences 

between 5.711a/5.756

– CALMET versions (5.53a vs. 5.726)—u

83% for scenarios 2, 3, (Pacific NW), 5 valley)

– CALPUFF versions (5.711a vs. 5.756)— 

7% for scenario 5 (deep valley)

• PROBLEM = incomplete documenta

– Missing Model Change Bulletins (MCB– No in-code comparisons– Inadequate model documentation
While we wait for response 

• BART usage

– “Good faith” effort to use “best” availab

model version

– Attempt to be “consistent” with App W 

‘wall off’ any potential bad precedents

• OAQPS becomes increasingly conc

about NSR/PSD permit modeling

– Appendix W provides “rules of the gam
Clearing the Air on CALPU

• OAQPS makes clear position statement a

monthly call with RO modelers (January 2

• Region 4 communicates with VISTAS so 

Brewer contacts OAQPS and facilitates discussion with TRC (Feb 2007)

• Request for documentation from TRC via 

VISTAS (Feb. 2007)

• Received documentation from TRC on M

15, 2007
CALPUFF Modeling System

Update on Recent Activities

• OAQPS updated regulatory version to 5.8 in June 

– CALMET, CALPUFF, CALPOST

• OAQPS has multiple concerns on science and co

implementation and has undertaken evaluations 

– Currently completing performance evaluations, both nea

LRT, and preparing documentation for release prior to 9

Conference

• Pending assessment of v5.8’n’ and v6 updates

– Currently “on hold” due to broader issues

• Goal = Get firm handle on science and its implem

so use of model with confidence in regulatory appengage with community at 9th Modeling Conferen
Game Plan & Next Step

• Post v5.8 update documentation on SCRAM• Issue near-field “Clarification Memo”• Post additional documentation of technical 

issues/concerns with near-field applications

• Complete CALPUFF performance evaluations an

document

• Compile list of issues and recommendations

– June workshop in Denver w/ R/S/L modelers– Communicate issues & recommendations to TRC/Scire– Discuss with FED users group (short-term and long-ter

implications)

• Engage community at 9th Modeling Conference, 

– Update on status, issues, and applications– Performance evaluation & findings– Science and implementation issues

• OAQPS expects to fund thorough and fully inform

review of CALPUFF modeling system