Regional Modeling

Joseph Cassmassi

South Coast Air Quality Management District

USA

Regional Modeling Applications

• Determine a “carrying capacity” for a region

• Provides a view of current, past and future air quality

• Planning tool to develop a long term control strategy

Expectations vs. Limitations

• Performance of regional models is as good as the worst component

• In data rich environments modeling errors range between 15-50%

• Requires a significant investment -- data

-- man hours-- computation

resources

Modeling Overview

• Goal or purpose

• Conceptual model

• Model selection

• Define modeling domain

• Emissions inventory

• Air quality and meteorological data

• Define an episode for model application

Conceptual Model

• Understanding of the overall picture-- extent of data availability-- confidence in the data-- processes that are contributing to

the observed air quality• Meteorological and air quality description of the

episode• Understanding of why the episode stands apart

from normal or average conditions

Model Selection

• Air quality-- platform (dedicated or family)

-- chemistry module-- dispersion

• Meteorological-- objective analysis

-- diagnostic analysis-- prognostic models

Modeling Domain

• Regional approach-- focus on Delhi?-- up and down wind areas

(from the conceptual model)• Meteorological modeling domain may be

greater than the air quality domain• Grid scales may be different• Need accurate terrain file

General Data Requirements

• Data required is domain dependent-- size

-- complexity of terrain-- pollutant

sensitive• Levels of model applications

-- limited surface and upper air -- moderately dense surface and multiple upper air

-- intensive field study

Ente l

Lo C añas

Esc. Ingeniería

Los T ilos

Lo P in to

San C ristóba l

La P la tina

C uesta C hada

C odigua

M aría P in to

Paine

La C am pana

La D orm ida

Lo P rado

M allarauco

P irque

C uesta Barriga

Q uilap ilún

E l M anzano

La R eina

E l Paico

Polpaico

-71.50 -71.25 -71.00 -70.75 -70.50 -70.25-34.00

-33.75

-33.50

-33.25

-33.00

Entel

Lo C añas

Esc. Ingeniería

Los T ilos

Lo P into

San C ristóbal

La P la tina

C uesta C hada

C odigua

M aría P in to

Paine

La C am pana

La D orm ida

Lo P rado

M allarauco

P irque

C uesta Barriga

Q uilap ilún

E l M anzano

La R eina

E l Pa ico

Polpaico

0

100

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300

400

500

600

700

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1000

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4500

C EN TR O N A C IO N AL D EL M E D IO AM B IEN TE

RED D E ESTACIO NES M ETEO RO LO G ICAS O PERADAS PO R CENM A(ubicadas en la Región M etropolitana)

Air Quality Data Requirements

• Surface-- routine air quality

monitoring -- chemical speciation ` -- define boundaries/initialization

• Upper air-- boundaries/initialization

-- transport

Meteorological Data Requirements

• Surface -- winds, temperature,

humidity -- insolation and cloud cover

• Upper Air-- winds, temperature, moisture

-- lapse rates and stability -- mixing heights

Southern California Monitoring

• Air Quality Monitoring -- 75+ ambient monitoring sites -- 10+ sites speciated data -- upper air characterization - as needed

• Meteorology -- 125+ monitoring or reporting sites -- 5 sounding/aircraft sites -- 10 radar profilers/sounders

Delhi Monitoring

• ~ 6-10 air monitoring sites --fixed & mobile vans --representative of high traffic areas --limited speciation

• Surface meteorological at air monitoring locations

• Twice daily soundings: Delhi, Gwalior, Jodhpur

Emissions

• Gridded emissions inventory -- point-- mobile-- area

• Day specific

• Allocation factor/surrogates

• Temporal profile

• Weekdays vs. weekends

Applications: Episode Selection

• Data Availability-- meteorology-- air quality-- boundary conditions

• Episode severity

• Representative of problem

• Field study data available

Delhi Profile

• Reasonably flat terrain

• Upper air --limited upper air meteorology maycharacterize domain

• Surface meteorology --river valleys will channel winds --urban heat island --Great Indian Desert --need additional monitoring

Delhi Profile (continued)

• Ambient air quality monitoring --may not characterize regional issue --need to characterize background

profile-- identify locations of maximum

pollution impact

Recommendations

• Meteorology-- enhance surface network-- consider upper air profiling

• Air quality-- enhance network-- speciation profiles-- characterize boundaries

• Investigate potential for field study-- PM - fall, Ozone - late spring