ARM Aerosol Working Group MeetingARM Aerosol Working Group MeetingSan Francisco – 2 November, 2006San Francisco – 2 November, 2006

Anne Jefferson (SGP, AMF)Anne Jefferson (SGP, AMF)John Ogren (Instrument Mentor)John Ogren (Instrument Mentor)

Betsy Andrews (IAP)Betsy Andrews (IAP)Allison McComiskey (NSA)Allison McComiskey (NSA)

Sharon Lewis (data manager)Sharon Lewis (data manager)Patrick Sheridan (IAP)Patrick Sheridan (IAP)

NOAA/ERSL Global Monitoring DivisionNOAA/ERSL Global Monitoring Division

Update on Aerosol Observing SystemsUpdate on Aerosol Observing Systems

Aerosol Observing SystemsAerosol Observing SystemsIn-Situ surface and aircraft profile measurements of aerosol In-Situ surface and aircraft profile measurements of aerosol

optical, chemical, size, hygroscopic and cloud-forming optical, chemical, size, hygroscopic and cloud-forming

propertiesproperties

SGPSGP• ARM central facility Lamont, OKARM central facility Lamont, OK

AMFAMF• Pt Reyes, CA 3/2005 - 9/2005Pt Reyes, CA 3/2005 - 9/2005• Niamey, Niger 12/2005-1/2007Niamey, Niger 12/2005-1/2007• Murg Valley, Germany 4/2007 -1/2008Murg Valley, Germany 4/2007 -1/2008• Taihu (Lake Tai), China 3/2008 - 2009Taihu (Lake Tai), China 3/2008 - 2009

BRW/NSABRW/NSA• Barrow AlaskaBarrow Alaska

IAP aircraft IAP aircraft • aircraft vertical profiling over SGP siteaircraft vertical profiling over SGP site

Comparison of AOS InstallationsComparison of AOS Installations

MeasurementMeasurement SGPSGP AMFAMF NSANSA IAPIAP

Scattering, low RHScattering, low RH 3-3- 3-3- 3-3- 3-3-

Scattering, f(RH)Scattering, f(RH) 3-3- 3-3- YY1-1-,,

40,65,85%40,65,85%

AbsorptionAbsorption 3-3- 3-3- 3-3- 3-3-

CNCN YY YY YY NN

CCNCCN YY YY YY NN

Size distributionSize distribution YY NN NN NN

Chemical comp.Chemical comp. YY NN YY NN

New additions listed in RED

Upgrades to SGP AOSUpgrades to SGP AOS 2005 2005

• 3 3 λλ PSAP PSAP• HTDMAHTDMA• build exterior pump boxbuild exterior pump box

20062006• DMT Cloud Condensation Nuclei counterDMT Cloud Condensation Nuclei counter

20072007• System reconfigurationSystem reconfiguration

20082008• add Aerosol Particle Sizer (APS). Particle sizes add Aerosol Particle Sizer (APS). Particle sizes

from 0.5 to 20 from 0.5 to 20 uumm

DMT CCN Counter

• Scans 7 supersaturations every 30 minutes from 0.17% to 1.38% supersaturation

•Measures the activated droplet size in 20 size bins from 0.75 to 10 microns

•One minute integration on droplet size and % supersaturation

•Installed 13-Sept-2006 at SGP

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

269.5 269.55 269.6 269.65

9/26/2006 time of day

CCN/CPC

0

0.2

0.4

0.6

0.8

1

1.2

1.4

% supersaturation

Ratio of CCN to CPC number concentrations Ratio of CCN to CPC number concentrations as a function of % Supersaturationas a function of % Supersaturation

SGP AOS repackagingSGP AOS repackaging Similar design and data acquisition as NSA, AMF Similar design and data acquisition as NSA, AMF

and IAP systemsand IAP systems Easy to update and compatible data acquisition Easy to update and compatible data acquisition

and processingand processing Upgrade humidifier for better %RH control, wider Upgrade humidifier for better %RH control, wider

range of % RH and more safety featuresrange of % RH and more safety features remote access and control of instrumentsremote access and control of instruments compact instrument packagecompact instrument package

• shorter sample linesshorter sample lines• less aerosol lossless aerosol loss• better temperature and RH controlbetter temperature and RH control

Open and accessible design for ease of Open and accessible design for ease of maintenance and repairmaintenance and repair

Spare parts and electronics are identical for all Spare parts and electronics are identical for all AOS systems and swapable with mentor stock of AOS systems and swapable with mentor stock of sparesspares

status of AMF AOS

• all instruments are currently working well

• rebuild of exterior pump box for next deployment

• neph circuit board and flow controller failure following a power outage in May, 2006 led to data loss for first part of summer monsoon season.

Wet

Sea

son

Dry

Sea

son

Wavelength dependence of the single scattering albedo

Single scattering albedo (SSA) values at 450(blue), 550(green) and 700(red) nm

The SSA values during the summer wet season show low ssa values (dark, absorbing aerosol) and little wavelength dependence. Noise is from low signal levels and sensitivity of psap to high RH

The SSA values during two dust events in the winter dry season show higher ssa values and a very strong wavelength dependence. (note that gaps in the data are when the absorption transmission dropped below 0.5)

wet season

dry season

aerosol hygroscopic growth at AMF Niger

Aerosol size

Q1

dry season

Q3

wet season

Q4

dry season

Sub micron 1.18 (0.23) 1.44 (0.29) 1.31 (0.52)

Sub 10 micron

1.01 (0.05) 1.16 (0.10) 1.05 (0.13)

- Aerosol fRH is lower in the dry season when cloud processing is low and transport is from the north- The fRH increases slightly during the wet season when more clouds are present and long range transport is from the southwest.- Aerosol fRH is greater for submicron aerosol which is a mixture of both dust and combustion products from local burning-Overall, fRH is very low throughout the year-Values are not reported for Q2 when there were problems with the instrument, neph circuit board failure and flow controller malfunction

NSA repackaging

OLD

•Humidified nephelometer•CCN measurements

NEW!!

In-situ aerosol profiles (IAP)• Cessna TU206F aircraft

• Operating over ARM SGP CART site

• In operation since October 2005

• replaced Cessna 172XP (Mar 2000 – Oct 2005)

• Research velocity: 50 m sec-1

• Ceiling ~15kft ( max. instrument payload of ~320 kgs.)

• Flight duration: ~4.5 hours

• Program has ~640 successful profile flights through September 2006

Inlet Details • Shrouded diffuser inlet made of anodized

aluminum with rounded leading edges (design adapted from T. Clarke, Univ. of Hawaii)

• Inlet plumbing is large diameter (2.22 cm I.D.) stainless steel tubing through wing

• Flow rate, inlet orifice size , and bend and tubing radii were chosen to minimize particle losses in inlet system

• Aerosol particle loss calculations indicate efficient transmission of optically important particles through inlet tubing (see plot at lower right). Turbulent deposition, diffusion, gravitational settling, and inertial impaction mechanisms were all considered.

Changes to Aerosol Optics Rack

Optics Rack Layout• TSI nephelometer to measure

sp at 3 visible wavelengths, 2 angular ranges, total aerosol size range, low RH

• Three Radiance Research nephs to measure total sp and f(RH) at 545 nm for submicron aerosols.

• RR nephs held at <40%, 65% and 85% RH.

• Miniature 3- Particle Soot Absorption Photometer (PSAP) to measure light absorption (available in 2007)

• In addition to aerosol optics instruments, optics rack holds power inverter, 2 DC power supplies, flow measurement and control hardware, and 2 LCD monitors.

<40%65%

85%

Ref, <40%

Status of IAP instruments

• high offset in high RH Radiance neph– work with Radiance to log raw data to

troubleshoot problem in lab

– start periodic CO2 span checks of neph calibration

• Add Multifilter Radiometer (MFR)

• Replace the current 3-wavelength PSAP with a redesigned mini-PSAP

NOAA “AAO” Instrument Package

Scattering coefficients

0

20

40

60

80

100

120

140

234.3 234.8 235.3 235.8 236.3 236.8 237.3

Scattering (Mm

-1)

Aircraft: Cessna T206HResearchPayload: 320 kgEndurance: 4.5 hrsCeiling (loaded): 4.7 km

Chemical Properties• Major ions

– PILS sampler

– analysis by IC

• Trace elements and total mass (planned)

– DRUM sampler

– analysis by PIXE,-attenuation

• Gases (O3, carbon-cycle flasks)

Radiative Properties• Light scattering,

backscattering,and absorption3 wavelengths,no size cut,<40% RH

• Scattering vs. RH1 wavelength,1 m size cut,<40%, 65%, 85% RH

Microphysical Properties

• NumberconcentrationD > 10 nm

• Size distribution20 < D < 500 nm

AAO/Satellite Validation StudiesScientific Objectives• To obtain a statistically-significant

data set of the vertical distribution of aerosol properties for evaluation of aerosol radiative forcing.

• To relate these properties to similar surface measurements to determine under what conditions surface measurements may be used to estimate column properties.

• To participate in the calibration and validation of aerosol remote sensing data and retrieval algorithms used by satellite sensors, including those onboard the “A-Train” Aqua and Calipso and the TERRA satellites.

A-Train satellite overpass tracks in the vicinity of the AAO base of operations. Overpasses along each track occur approx. twice per month.

RecommendationsRecommendations

Aerodynamic particle sizer (APS)Aerodynamic particle sizer (APS)

NSA vertical profiles to link aerosol NSA vertical profiles to link aerosol above and below cloud base with the above and below cloud base with the surface aerosol.surface aerosol.