ICARTT 2004Ronald H. Brown – Measurements Relevant to

Aerosol Direct Radiative Forcing

Regional Assessment of Aerosol Direct Radiative Forcing -

MEASUREMENTSCATEGORY Measured Parameters Platform

Aerosol Chemical Composition

Anions and cationsElemental carbon (EC)Organic carbon (OC)Organic carbon (speciated)Trace elements

RHB, P3, CPRHBRHB, P3, CPRHB, CPRHB

Aerosol Physical and Optical Properties

Number vs size, accumulation &coarse modesAbsorption (450, 550, 700 nm)Scattering & backscattering (450, 550, 700 nm)f(RH)Lidar backscatter profiles

RHB, P3RHB, P3, CPRHB, P3, CPRHB, P3RHB, NOAA-RS, CP

Radiative Properties Aerosol Optical Depth (spectral)Radiative fluxes, solar and longwave, upwelling and downwelling (spectral)Direct, diffuse, and total irradiances (spectral where possible)Surface albedo

RHB, NASA-RS, MISRNASA-RS, MISR

P3, NASA-RS

NASA-RS

Meteorological Parameters Wind speed, direction, RH, T, pressure, cloud type and amount, visibility

RHB

Measurements: Sub-1 m particles

• Cavity Ring Down Extinction Cell Aerosol extinction & f(RH) (66% / 30%) continuous

plus humidity scans

• HumidographAerosol scattering & f(RH)

humidity scans (increasing and decreasing RH)between 35 and 90% RH

• Aerosol composition Aerodyne Mass Spectrometer, PILS, impactors

SO4=, NO3-, NH4+, POM, EC, Trace elements

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

Ext

inct

ion

(M

m-1

)

807060504030DOY

Extinction Humidogram"Upper Branch"

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

f(R

H)

80706050%RH

Humidogram Upper Branch Lower Branch

RH RH

f(R

H)

f(R

H)

Comparison of Hygroscopic Growth Dependence of Aerosol Scattering from Humidified Nephelometer

and Extinction from CRDDOY 203 (12:00 UTC)

1.5

1.4

1.3

1.2

1.1

1.0

Ca

vity

Rin

g D

ow

n f

(RH

) (6

6%

/ 3

0%

)

0.80.70.60.50.40.30.2NR Organic Mass Fraction

195 - 280º Offshore Wind Sector

0.120.100.080.06

m44 / Organic Ratio

Dependence of f(RH) on aerosol composition

Comparison of Extinction Measured by Cavity Ring-down Extinction Cell and OPAL (LIDAR) at = 355 nm

280

260

240

220

200

180

160

140

120

100

Ex

tin

cti

on

a

t 3

55

nm

(M

m-1

)

198.40198.30198.20198.10

DOY

Opal_ExtinctionExtrapolated Data (CRD)

Ext @ 60% RH Ext @ 70% RH Ext @ 80% RH Ext @ 85% RH

Ext

inct

ion

(Mm

-1)

Ambient RH = 80 to 90%

0.8

0.6

0.4

0.2

0.0

AO

D

0.60.40.20.0AOD (s/n 5355)

1.2

1.0

0.8

0.6

0.4

0.2

0.0

AO

D

1.21.00.80.60.40.20.0

1.0

0.8

0.6

0.4

0.2

0.0

1.00.80.60.40.20.0

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.60.50.40.30.20.10.0AOD (s/n 5355)

380 nm 500 nm

675 nm 870 nm

s/n 3803 s/n 4080

y = 0.98x + 0.03

R2

= 0.99

y = 0.99x + 0.02

R2 = 0.99

y = 0.97x - 0.01

R2 = 0.98

y = 0.98x + 0.02

R2 = 0.98

y = 0.95x + 0.01

R2 = 0.96

y = 0.98x + 0.01

R2 = 0.95

y = 0.91x + 0.01

R2 = 0.91

y = 0.93x + 0.01

R2 = 0.89

Comparison of 3 Microtops Units for 380, 500, 675, 870 nm

1.2

1.0

0.8

0.6

0.4

0.2

0.0

AO

D (

s/n

3803

)

1.21.00.80.60.40.20.0AOD (s/n 4080)

y = 0.99x + 0.001

R2 = 0.99

Comparison of 2 Microtops Units for 440 nm

45

44

43

42

-71 -70 -69 -68 -67

0.8

0.6

0.4

0.2

0.0

AO

D (500 nm

)

RHB: Spatial Distribution of AOD measurements

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

7/6/04 7/10/04 7/14/04 7/18/04 7/22/04 7/26/04 7/30/04 8/3/04 8/7/04 8/11/04GMT Date

400

300

200

100

0

1/M

m, 5

50 n

m

380nm 440nm 500nm 675nm 870nm

Can

adia

nF

ores

t Fire

s

Neph Sub-10 um Scattering

RHB: Time Series of Sub-10 um Scattering and AOD

J31Overflights

RHB: Time Series of Sub-10 um Scattering and AOD

1.0

0.8

0.6

0.4

0.2

0.0

3:00 PM7/11/04

4:00 PM 5:00 PM 6:00 PM 7:00 PM

GMT Date

100

80

60

40

20

0

1/M

m, 5

50 n

m

380nm 440nm 500nm 675nm 870nm

Canadian Forest Fires

Neph Sub-10 um Scattering

-2.0x10-3

-1.5

-1.0

-0.5

slo

pe

7/10 7/14 7/18 7/22 7/26 7/30 8/3 8/7GMT Date

1.2

0.8

0.4

0.0

AO

D, 5

00

nm

AOD = m* + b

Time series of AOD and spectral slope

Regions of higher AOD: Polluted, more small particles stronger spectral dependence

0.20

0.18

0.16

0.14

0.12

0.10

0.08

0.06

900800700600500400

1.2

1.0

0.8

0.6

marine, low AOD polluted, high AOD

Wang et al., JGR, 2003.

Used shipboard AOD measurementsto determine the accuracy of AOD retrievals from the GMS5 geostationary satellite.

Markowicz et al., JGR, 2003.

Used shipboard f(RH) measurementsto estimate the dependence of Surface and top of atmosphere forcing on RH.

Diurnally averaged aerosol forcingefficiencies determine from a radiative transfer model as a functionof RH.

Contacts:

f(RH): Tahllee Baynard, tbaynard@al.noaa.govWei Wang, weiwang@uiuc.edu

Scattering, backscattering, absorption: Trish Quinn, patricia.k.quinn@noaa.gov

Also available at http://saga.pmel.noaa.gov/data

AOD: Trish Quinn, patricia.k.quinn@noaa.gov Also available at http://saga.pmel.noaa.gov/data