Airborne sunphotometer

measurements of aerosol in ACE-Asia

and their comparisons to

correlative measurements

Beat Schmid et al.BAER Institute, Sonoma, CA

Presented by

Michael BoxUniversity of New South Wales, Sydney

Hegg, D, Covert, D, Univ. of Washington, Atmospheric Sciences, WA

Hsu, C, Welton, E, GEST/UMBC, NASA Goddard Space Flight Center, Greenbelt, MD

Redemann, J, Bay Area Environmental Research, Institute, Sonoma, CA

Livingston, J , SRI, International, Menlo Park, CA

Russell P, NASA, Ames Research Institute, Moffett Field, CA

Wang, J, Flagan, R, Seinfeld, J, California Institute of Technology, Pasadena, CA

Bates, D, University of, Miami, Coral Gables, FL

Jonsson, H, CIRPAS, Marina, CA

Co-authors

Title

Slide 16

ACE-Asia Ob jectives:

Characterization: Determine the phy sical, che mical, andradiative properties of the m ajor aerosol types in the Ea stern A siaand Northwest Pacific region and inves tigate the relationshipsamong the se properties.

Radiation: Quant ify the interactions between aerosols andradiation in the Eastern Asia and Northwest Pacific region

Processes: Quant ify the phy sical and chemical p rocessescontrolling the evo lution o f the major aerosol types and inparticular of their phys ical, chemical, and radiative properties.

Make Observations to Improve Models of Aerosol Concentrations and Impacts.

Satellite, Ship and Aircraft Platforms in ACE-Asia

Groundbased observations

Lidars, aerosol chemistry & physics, optical properties, and radiation

AATS-6 AATS-14

NASA Ames Airborne Sunphotometers (AATS)

AOD (350-1558 nm) and H2O

C-130

Twin Otter

ACE-Asia C-130 Flight Tracks

C-130

Ron Brown Twin Otter

40

35

30

25

145140135130125120Longitude

Val

idat

ion

Validation of SeaWiFS AOD (Hsu et al. algo)

with AircraftSun photometer

Flying low over the ocean

AATS vertical profiles during ACE-Asia

AATS-14

AATS-6

In situ measurement of

Extinction =

Absorption

• Particle Soot Absorption Photometer (PSAP, =550nm)

• noisy (averaging)• low RH• Corrections

– scattering contribution

– inlet-cutoff (Da=8m)*

– correct to ambient RH*

Scattering

• Nephelometers = 450, 550, 700 nm, low RH = 550 nm, RH=20,60,85%

• Corrections– light source

– angular truncation (7°-170°)

– inlet-cutoff (Da=8m)*

– correct to ambient RH

+

*correction not required or done

Closure between airborne sunphotomter and in-situ

ACE-Asia Column ClosureLayer AOD

y = 0.826x + 0.0386

R2 = 0.6267

0

0.1

0.2

0.3

0.4

0.5

0 0.1 0.2 0.3 0.4 0.5

AATS-14

Nep

h+

PS

AP

ACE Asia Column ClosureAerosol Extinction

y = 0.8593x + 0.0116

R2 = 0.6004n = 2476

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 0.1 0.2 0.3 0.4

AATS-14

Ne

ph

+P

SA

P

Closure between airborne sunphotomter and in-situ for 9 profiles

In situ measurement of size distribution and computation of extinction

• Twin DMA, D=15-1000 nm (close to ambient RH)• Aerodynamic Particle Sizer, D=0.5 - 8 m (drier than ambient RH),

• adjust to ambient RH• compute extinction, needs m} needs composition

Wang et al. 2002, JGR (submitted)

Wang et al. subm. JGR, 2002

Closure experiment with airborne sunphotometer and lidar on ship

Ron Brown Twin Otter

R/V Ron Braun CIRPAS Twin Otter