vertically resolved aerosol optical properties over the arm sgp site b. schmid, h. jonsson, a....

Vertically resolved aerosol optical properties over the ARM SGP site

B. Schmid, H. Jonsson, A. Strawa, B. Provencal, K. Ricci, D. Covert, R. Elleman, W. P. Arnott, A. Bucholtz, P. Pilewskie, J. Pommier, T. Rissman, T. VanReken, J.

Wang, J. Seinfeld, R. Flagan, J. Redemann, J. Eilers, R. Ferrare, E. J. Welton, and many others Photo from Roy Woods

• Aerosol: number, size distr., extinction, scattering (cavity ring-down), absorption (photoacoustic) hygroscopicity, aerosol optical depth

• Gases: Water vapor

• Cloud: liquid water, droplet size distribution, CCN

• Radiation: solar and IR, up and downwelling, broadband and spectral

• Stabilized platform

• Flew 60.6 flight hours during 16 flights on 15 days

CIRPAS Twin OtterARM Aerosol IOP – May 2003

Photo courtesy Yin-Nan Lee, BNL

Raman Lidar

Disclaimer: Talk covers only small subset of IOP data. All results are preliminary

SMART trailer (Tsay, Ji)

NASA Ames Airborne Tracking SunphotometerAATS-14: 354-2139 nm

Aerosol Optical Depth and H2O columnAerosol Extinction and H2O density in suitable profiles

H2O Density Comparisons (all flights)

AATS-14 vs. in situ Raman Lidar (< 3km) vs. in situ

In situ measurement of

Extinction =

Absorption

• Particle Soot Absorption Photometer (PSAP)

=467, 530, 660 nm• low RH

• Corrections (Bond et al., 1999)– scattering contribution– …– inlet-cutoff (Da=8m)*– correct to ambient RH*

Scattering

• Nephelometers– TSI: = 450, 550, 700 nm,

low RH– RR: = 540 nm,

RH=20,60,85%

• Corrections (Anderson & Ogren, 1998)

– light source– angular truncation (7°-170°)– inlet-cutoff (Da=8m)*– correct to ambient RH

+

*correction not required or done

Measurements: D. Covert & R. Elleman

L

cR L L Lext Ray absorber( )1 1

ext c aer 1 1 1

0( )

where L = cell lengthc = speed of lightR = reflectivity of mirrors = coefficient of extinction, Rayleigh, gaseous absorbers

where = ringdown timeaer = with aerosol0 = without aerosol

Iin(t)

ring-down cavity

Iout(t)

time

Cavity Ring-Down -The Ping-Pong Model

A. Strawa, K. Ricci, B. Provencal

Elevated layer as seen from Twin Otter on May 27, 2003Photo courtesy of Roy Woods

R. Husar, http://capita.wustl.edu/

MODIS 5/14/2003

http://rapidfire.sci.gsfc.nasa.gov/gallery/?2003134-0514