arm may 2003 aerosol iop mission objectives
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ARM May 2003 Aerosol IOPMission Objectives
(based on Schmid/Pilewskie/Strawa/Russell/Redemann/BergstromARM ST proposal plus possible add-ons)
Vertically resolved aerosol optical properties over the ARM SGP site Motivation: unrealistic SSA, no closure IAP, BBHR VAP
•Extinction closure•Absorption closure
Ad-ons•Satellite validation•Spatial variability
DOE/ARM May 2003 Aerosol IOP
Aerosol: number, size distr., hygroscopicity scattering, absorption (PSAP, photo-acoustic, CRD)
Cloud: liquid water, CCN, size distr.
Radiation: solar and IR up and downwellingbroadband and spectral.
Aerosol Optical Depth, H2O
Groundbased: same + lidars+…Groundbased: same + lidars+…
In-situ Aerosol Profiles at SGPIn-situ Aerosol Profiles at SGP
CIRPAS Twin OtterCIRPAS Twin Otter
Extinction closure
• "Can in situ measurements of aerosol properties account for the solar beam attenuation (extinction) by an aerosol layer or column?"
• “How about lidars or satellites?”• Measuring solar beam attenuation by an AATS on the
same aircraft as in situ sensors allows an exact match in the aerosol layers described by the attenuation and in situ measurements.
• Such comparisons have revealed important insights about aerosol sampling and inadvertent modification in such previous experiments as TARFOX, ACE-2, SAFARI, ACE-Asia, CLAMS …
Extinction closure
• AATS-14
• CW-CRD
• Neph+PSAP (or Photoacoustic)
• From Size Distr. and Comp. (TDMA, PCASP, CAPS, FSSP, APS)
• Lidars (CARL, MPL, …)
• IAP
Extinction closure between AATS-14 and Neph+PSAP for 14 profiles
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
is = (1.03±0.09) sp ± 0.052)
r2 = 0.98
Layer AOD from Sun photometer,sp
Laye
r A
OD
fro
m in
situ
mea
sure
men
ts,A
OD
is
Best fit to ax+b1 to 1 line
AOD
AOD
AOD
Layer AOD Closure in SAFARI-200015 vertical profiles, from Magi et al., subm. JGR 2002
How well did past campaigns do on AATS vs Neph+PSAP comparisons?
U.S. East Coast, 1996 (Hegg et al., 1997, Hartley et al., 2000)
Canary Islands, 1997 (Schmid et al., 2000)
Eastern Asia, 2001
C-130: Redemann et al., 2003
Twin Otter: Schmid et al., 2003
Southern Africa (Magi et al., 2002)
U.S. East Coast, 2001 Hobbs et al., (in preparation)
Absorption Closure
• PSAP
• CW-CRD
• Photoacoustic
• Aeronet Cimel
• Flux Divergence (SSFR)
Downwelling Flux: F
Upwelling Flux: F
Net Flux: F- F
Flux Divergence (absorption):
(F- F)2000m- (F- F)43m
Fractional absorption:
[(F- F)2000m- (F- F)43m]/ F2000m
2000 m
43 m
Satellite Validation (over land)MISR, MODIS, ATSR/2
Spatial Variability (MFRs at SPG)
CIRPAS Twin Otter Payload May 2003 IOP
Available Measurement Instrument PI/Organization
Aerosol size distribution 10 nm-1µm at 2 RH (one can be ambient)
TDMA System (cabin) Caltech
Aerosol/cloud size distribution d=0.1-2.5 µm d>0.3 µm
PCASP probeCAPS probe
CIRPAS
Aerosol/cloud size distribution d>0.5 µm
FSSP probe CIRPAS
Aerosol size distribution d>0.5 µm
TSI Aerodynamic Particle Sizer (wing) CIRPAS
Total aerosol number concentration Condensation Nucleus Counters (CNCs)
CIRPAS
Cloud liquid water contentGerber PVMJohnson probe on CAPS CIRPAS
Meteorological state parameters:Dry-bulb temperatureDew point temperaturePressureWind vector (mean)
Gust probe
CIRPAS
Aircraft state parameters:PositionAirspeedPressure altitudeAttitude (pitch, roll, yaw)
CIRPAS
Cloud condensation nuclei supersaturation spectrum
New Caltech CCN instrument. Flew in CRYSTAL-FACE
Caltech
Available Measurement Instrument PI/Organization
Aerosol optical properties TSI Nephelometer 3 wavelengthsSoot Photometer (PSAP 550 nm) (cabin)
D. Covert/ U. Wash.
Aerosol hygroscopic properties Humidigraph (cabin) 550 nm, RH=20,60,85%
D. Covert/ U. Wash
Aerosol optical depth (354-1560 or 2140 nm, 14 channels), water vapor, extinction and water vapor density in feasible profiles
NASA Ames Airborne Tracking Sunphotometer (AATS-14)
B. Schmid/NASA Ames
Aerosol light extinction coefficient (690 and 1550 nm)
Cavity ring-down extinction cell A. Strawa/NASA Ames
Downwelling and Upwelling Solar Irradiance (broadband)Stabilized platform
Kipp and Zonen CM-22 pyranometersA. Buchholz/NRLMcCoy/SANDIA
Downwelling andUpwelling SolarSpectral Irradiance,1320 channels
NASA Ames Solar Spectral Flux Radiometer (cabin)
P. Pilewskie/NASA Ames
Aerosol absorption Photoacoustic Instrument Pat Arnott/DRI
NASA Ames Airborne
14-channel
Sunphotometer (AATS-14)
AOD and H2O
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