Understanding Haze in Big Bend National Park Big Bend Regional Aerosol and Visibility

Observational (BRAVO) StudyMark Scruggs, National Park Service

Presented at the BRAVO Public Meeting Alpine, Texas September 22, 2004

Annual Extinction by ComponentBig Bend National Park--Best Days

Coarse Mass Nitrate OrganicsSoil Soot Sulfate

Ext

inct

ion

(Mm

-1)

0

1

2

3

4

5

6

7

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Annual Extinction by ComponentBig Bend National Park--Worst Days

Coarse Mass Nitrate OrganicsSoil Soot Sulfate

Ext

inct

ion

(Mm

-1)

0

10

20

30

40

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Background - Why study haze at Big Bend NP?

A beautiful, remote, and scenic park

16 1/Mm / 10 yr

4.3 1/Mm /10 yr

Insignificant

0

10

20

30

40

50

60

70

90 92 94 96 98 00 02Year

Part

icul

ate

Bex

t (1/

Mm

)

With Some of the worst haze in the west …And Getting Worse

Summary of IMPROVE Extinction Trends by Group and ComponentBig Bend National Park

Bext is Reconstructed Extinction Excluding Rayleigh

Component Bext Coarse Mass Nitrate OrganicsSoil Soot Sulfate

Slop

e (M

m-1

/yr)

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Group10 90 100

0 to 0.1

0.1 to 0.2 0.2 to 0.3

0.3 to 0.4

0.4 to 0.5 0.5 to 0.6 0.6 to 0.7 0.7 to 0.8 0.8 to 0.9 0.9 to 1

R-squared of Regression Between Ammonium Sulfate Extinction and RBext

So, what did we learn from the BRAVO Study?