Cluster Analysis of Air Quality Data for CCOS Study … CCOS...Cluster Analysis of Air Quality Data for CCOS Study Domain ... – Preliminary North SJV wind field clustering ... –

Cluster Analysis of Air Quality Data for CCOS Study Domain

Scott BeaverAhmet Palazoglu, P.I.University of California, Davis

Dept. Chemical Engineering & Materials Science

CCOS Technical Committee MeetingCal/EPA Building, 1001 I St., Sacramento, CA

Thursday 31 March 2007

Department of Chemical Engineering and Materials Science

Overview• Project: Cluster Analysis for CCOS Domain

I. Intra-basin analyses: wind patterns & synoptic regimesII. Inter-basin meteorological response of O3 levels

• Intra-basin analyses:– Completed Bay Area analysis

• Strong synoptic influence; seabreeze cycles

– Preliminary North SJV wind field clustering• Synoptic & ventilation effects

– Preliminary Central SJV wind field clustering• Synoptic & mesoscale (Fresno eddy) effects

– Preliminary South SJV wind field clustering• Synoptic effects; mesoscale variability difficult to capture

– Initial Sacramento Valley & Mountain Counties analysis

• Future work and recommendations


Cluster Analysis for CCOS• Scope of 2-year project

I. Intra-basin wind field cluster analyses– Requires continuous, hourly surface wind data– Days grouped by diurnal wind field patterns– Reveals synoptic and mesoscale flow regimes

II. Inter-basin analysis

• Study Domain– 6 CCOS air basins

• San Francisco Bay Area• SJV: split into North, Central, & South• Sacramento Valley• Mountain Counties

– 1996-2004 ozone seasons (1 May – 31 October)



San Francisco Bay Area

SFBA: 4 clusters for 976 days1

996

199

719

9819

9920

0020

0120

02

Jun 01 Jun 15 Jul 01 Jul 15 Aug 01 Aug 15 Sep 01 Sep 15 Sep 30

200

3


*Beaver and Palazoglu, 2006: Cluster analysis of hourly wind measurements to reveal synoptic regimes affecting air quality. Journal of Applied Meteorology and Climatology, 45, 1710—26.

5600

5600

5650

5650

5700

5700

57505750

5800

5800

5850

5850

5900

5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5550

5550

5600

5600

5650 5650

5700 57005750 57505800

58005850

5850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5600

5600

5650

5650

5700

5700

5750

5750

58005800

5850

5850

5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5550

5600

5600

56505650

5700 57005750 5750

5800 5800

58505850

5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

SFBA clusters = synoptic regimes


H

R

V2V1

Onshore High: 353 d, 13% episodes Offshore High: 86 d, 13% episodes

Weaker Trough: 309 d, 0% episodes Deeper Trough: 309 d, 0% episodes

*Beaver, Palazoglu and Tanrikulu, 2007: Cluster sequencing to analyze synoptic transitions affecting regional ozone. Journal of Applied Meteorology and Climatology, in press.

Synoptic Transition Probabilities• R transitions rapidly to H

– Severe, multi-day episodes– Reverse H�R does not occur– Polar low may “save” SFBA from episode

• Persistence of H indicates stability– Displaced by sufficiently deep trough (e.g. V2)– Bulk of episodes during persistent H

• Transitions from V1 & V2 driven by global met.– Troughs may persist for long periods; low O3 levels– Transition to H or R will occur unless O3 season ends


SJV SLAMS network


SLAMS, CIMIS, RAWS & NCDC


North SJV Wind Monitors


Wind Speed Errors at Tracy


1996—1999 are similar to 2001—2004.

05

1015

Tracy-Patterson Rd. -- Wind Speed

2000

05

1015

2001

05

1015

2002

05

1015

2003

May01 Jun01 Jul01 Aug01 Sep01 Oct01 Nov0105

1015

2004

Tracy-Patterson Rd. -- Wind Direction Hourly Distribution

2000

2001

2002

2003

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Hour of Day

2004

Wind Direction Errors at Tracy


1996—1999 are similar to 2001—2003.

Gantt chart for N-SJV


Yellow = 1 Nov—30 Apr winter data (not clustered)Blue = clustered stations (included in Total)Red = non-clustered stations (excluded from Total)

55005550

5550

56005650

57005750

58005850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

555056005650

57005750

5800

5850

5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

54505500

5550

5600 5650 570057505800

5850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5550

5600

5600

56505700

57505800

5850 5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5500

5550

560056505700

575058005850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N


H: 179 days, 42%

H H

R

V2V1

V

R: 264 days, 19%H/V: 212 days, 25%

V2: 108 days, 6%V1: 299 days, 12%

N-SJV 0900 PST Wind Field


Magenta: Carquinez Strait— Ft. Funston, Pt. San Pablo, Suisun, Bethel Is.

Blue: Altamont Pass— Kregor Peak, TracyRed: Pacheco Pass— Los BanosBlack: SJV floor

H H/VR V1 V2Increasing marine ventilation: R < H < H/V < V1 < V2

N-SJV Seasonal Distribution


0

1

Black: Probability a Cluster is Realized Within 5 Days of Any Day of YearRed: Probability a Cluster is Realized as Exceedance Within 5 Days of Any Day of Year

0

1

0

1

0

1

01 May 01 Jun 01 Jul 01 Aug 01 Sep 01 Oct0

1

Day of Year

H

H/V

R

V1

V2

N-SJV Ventilation


10

20

30

40

50Tracy Stockton Merced

1500 PST Temperature (oC)

-5

0

5

10

15

1000 PST Westerly Speed (m/s)

Bethel Island Tracy Los Banos

H H/V V1

V2 R H H/V V1

V2 R H H/V V1

V2 R

Altamont Pass Wind Distribution


0800PST Wind Distribution

H (164 d)

Tra

cy

H/V (189 d) V1 (281 d) V2 (89 d) R (245 d)

Ple

asan

ton

Kre

gor

Pea

k

0 0.25 0.5 0.75 1

N-SJV Synoptic Sequencing

• α = 0.05– R H/V disfavored– Clusters occur in different seasons (trivial result)

• α = 0.15– R H favored

– H H/V favored

– H/ V V favored

– V R favored

• Compare to Bay Area– Transitions significant at α < 0.02– Stronger synoptic influence than N-SJV

Central SJV Wind Monitors


Annual Biases in Wind Direction


090

180270360

1999

Dir

Clovis-N Villa Wind Direction

090

180270360

2000

Dir

090

180270360

2001

Dir

090

180270360

2002

Dir

01 May 01 Jun 01 Jul 01 Aug 01 Sep 01 Oct 01 Nov0

90180270360

2003

Dir

2000—02 are ~15o more westerly than other years.

Upslope/Downslope Cycle

30 Jul 05 Aug 10 Aug 15 Aug0

90

180

270

360

2003

Dir


Wind direction at SLAMS Sequoia monitor for 20 days during 2003.

Flow switches from easterly to westerly.

Daytime upslope flows; nighttime drainage flows

Diurnal cycle largely captures local effects.

Signal is not well modeled by clustering algorithm.

Gantt chart for C-SJV


Magenta: stations with annual biases

5600

5600

565057005750

5800

5850

5900 165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5650 57005750

58005850

5900 165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5450

5500

55505600

5650 57005750

58005850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5550 56005650

57005750

58005850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5550

56005650

5700575058005850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N


H: 203 days

H H R

V

V

R: 341 daysH/V: 169 days

V/I: 378 daysV: 279 days

IV?

C-SJV 8-hr O3 Exceedances


H RH/VV/IV

Ventilated regime episodes favor Sequoia.

Anti-cyclonic regime episodes favor SJV floor.

Percentage of days in each cluster that are 8-hr O3 exceedances

279 d 378 d 169 d 203 d 341 dTotal 40% 32% 64% 92% 59%SJV floor 29% 17% 34% 84% 52% Parlier 20% 15% 28% 73% 43% Clovis 18% 6% 12% 62% 33%

Sequoia 25% 25% 57% 64% 33%SJV floor & Sequoia 14% 10% 27% 56% 26%

C-SJV Seasonal Distribution

0

1


0

1

0

1

0

1


1

Day of Year


H

H/V

R

V/I

V

C-SJV Synoptic Sequencing

• Direct transitions between H, R, and Voccur infrequently

• H/V and V/I are “intermediate” states– C-SJV is buffered from synoptic effects

– Synoptic transitions have less effect on O3levels than for N-SJV (than for Bay Area)

• Mesoscale effects important for C-SJV


The Fresno Eddy


Magenta: Carquinez Strait— Ft. Funston, Pt. San Pablo, SuisunBlue: Altamont Pass— Kregor Peak, TracyRed: Pacheco Pass— Los BanosCyan: Parkfield (west) & Sequoia (east)Yellow: Carrizo Plain

R H/VH V V/IDecreasing eddy strength: H > R > H/V > V > V/I

Eddy Strength and O3 Levels


Strong eddyNo/weak eddy

406080

100120

WeekdaysWeekends

406080

100120

406080

100120

Da

ily M

axi

mu

m 8

-hr

O 3 leve

l at P

arli

er

406080

100120

-6 -4 -2 0 2 4 6

406080

100120

Parlier southerly wind component at 0900 PST (m/s)

R

H/V

H

V

V/I

?


5650

57005750 5800

5850

5900

Eddy (133 d)

5550 5600

565057005750

5800

5850

Eddy (188 d)

5500

55505600

5650 5700

57505800 5850

Eddy (207 d)

54505500

5550 560056505700575058005850

Stagnant (21 d)5600

5650

5700

57505800

5850

5900

Stagnant (19 d)

555056005650

5700

5750

58005850

5900

Stagnant (15 d)

5550

56005650

57005750

5800

5850

Stagnant (43 d)

56005650

57005750

5800

5850

5900

No eddy (14 d)55005550

5600

56505700 5750

58005850

No eddy (60 d)5550

56005650

57005750

5800

5850

No eddy (118 d)

56005650

57005750

5800

585059

00

Eddy (193 d)5450

5500 5550

56005650 57005750

58005850

Eddy (296 d)R H/V V V/IH

Eddy Strength & Marine Ventilation

Within each regime, enhanced marine ventilation can suppress eddy formation

South SJV Wind Monitors


Gantt chart for S-SJV


56005650

5700

5750

5800 5850

5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N 5600

56505700

575058005850

5900

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

545055005550

5600 5650

57005750

5800

5850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5500

55505600

5650 57005750

58005850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N

5500

5550

5600 5650

57005750

5800

5850

165° W 150° W 135° W 120° W 105° W 90° W

30° N

45° N

60° N


H/V: 206 days, 64%

H H R

V

V

R: 373 days, 62%H: 354 days, 58%

V/I: 317 days, 22%V: 160 days, 36%

I?V


H

H/V

R

V

V/I

0

1


0

1

0

1

0

1


1

Day of Year

S-SJV Seasonal Distribution

Progress


Non-contracted quality assurance is a critical but time consuming step which has delayed Phase I progress.

Obt

ain

data

Qua

lity

assu

ranc

e

Win

d fie

ld c

lust

erin

g

Ozo

ne c

lust

erin

g

Intr

a-ba

sin

repo

rt

Syn

optic

seq

uenc

ing

Rel

ate

win

d an

d oz

one

clus

ters

Inte

r-ba

sin

syno

ptic

an

alys

is

Inte

r-ba

sin

tem

pora

l an

alys

is

San Francisco Bay Area X X X X X X XSJV North X X X \ \ XSJV Central X X X \ \ XSJV South X X \ \Sacramento Valley XMountain Counties X

Phase I Phase II

Recommendations• Transport analysis for identified met regimes using a

(back-trajectory) transport model.– Transport through gaps in Coastal Range– Transport patterns from major source areas

• NOx/VOC ratio and O3 sensitivity– Role of meteorology

• El Nino effects• Wild fire analysis• Vertical analysis

– Visalia profiler– Limited soundings?

• AQM performance evaluation• … and others from project work plan ???


Documents

Cluster Analysis of Air Quality Data for CCOS Study … CCOS...Cluster Analysis of Air Quality Data for CCOS Study Domain ... – Preliminary North SJV wind field clustering ... –