Overview of the Atmospheric Overview of the Atmospheric Radiation Measurement (ARM) Radiation Measurement (ARM) Program’s Mobile Facility (AMF)Program’s Mobile Facility (AMF)

Dave Turner

University of Wisconsin – Madison

COPS Workshop10-11 April 2006Hohenheim, Germany

The Real People The Real People Behind the AMFBehind the AMF

Head Scientist: Mark MillerTeam Members: Mary Jane Bartholomew,

Larry Jones, Kim Nitschke, Doug SistersonChief Engineer: Kevin WidenerProgram Manager: Wanda Ferrell

The ARM Mobile FacilityThe ARM Mobile FacilityInitially Deployed in 2005Initially Deployed in 2005

Pt. Reyes, CaliforniaNiamey, Niger, Africa

CharterCharter Detailed measurements of the cloudy

atmospheric column – in regions of the climate system that are generally

undersampled– in association with the international atmospheric

science community Subset of instruments located at ARM’s fixed

sites– Active and passive sensors– Enhanced surface aerosol system

Deployment duration is 6-12 months

Site Selection ProcessSite Selection Process

International Proposal Competition – ARM Climate Research User Facility

(ACRF) Board selects winning proposal Composed of 40% ARM Scientists and 60%

external scientists Final decision is made by the ARM Program

Manager Proposals rated on scientific merit, facility

leverage, and logistical feasibility

Active and Passive Cloud Active and Passive Cloud Remote SensorsRemote Sensors

3.2-mm Doppler Cloud Radar (WACR)– 30-m vertical resolution– 2-sec temporal resolution– 256 pt. Doppler spectrum at each range gate,

continuously recorded– Polarization– Minimum detectable signal ~ -40 dBZ at 5-km– Sensitivity may exceed –60 dBZ in lowest 1-km– Internal calibration verified by corner reflector

3.2 mm Cloud Radar Doppler 3.2 mm Cloud Radar Doppler Velocity from Niamey, NigerVelocity from Niamey, Niger

“First light”

Active and Passive Cloud Active and Passive Cloud Remote Sensors (cont.)Remote Sensors (cont.)

Vaisala Laser Ceilometer– 905-nm– 15-m, 15-sec resolution– Backscatter profile, cloud base height– Maximum height in cloud free atmosphere: 5.5-km

Micropulse Lidar (MPL)– 523-nm– 30-m, 30-sec resolution– Backscatter Profile, Cloud base height– Maximum height in cloud free atmosphere: 18-km– Cloud optical thickness, aerosol extinction

0000 12000

5

10

15

20

Time (UTC)

Hei

gh

t (k

m)

Biomass Burning

Dust

LIQUID CLOUDS

MPL Example From NiameyMPL Example From Niamey

2400

Bac

ksca

tter

(ar

b u

nit

s)

Active and Passive Cloud Active and Passive Cloud Remote Sensors (cont.)Remote Sensors (cont.)

2-Channel Microwave Radiometer (MWR)– 23.8 and 31.4 GHz– Precipitable water vapor and integrated liquid

water path

12-Channel Microwave Radiometer Profiler– Vertical profiles of water vapor, temperature, and

liquid water content (coarse)– 5 min temporal resolution– 5 frequencies near water vapor resonance

between 22.235 and 30 GHz– 7 frequencies in the band of oxygen resonances

between 51 and 59 GHz

ARM’s MWRsARM’s MWRs

Clear Sky Microwave Optical Depth Spectrum

Active and Passive Cloud Active and Passive Cloud Remote Sensors (cont.)Remote Sensors (cont.)

Wind Profiler – 75-m, 6-min resolution– 915 MHz [1270-1400 MHz COPS]– Minimum Height: 120-m– Maximum height: 5.5-km

Atmospheric Emitted Radiance Interferometer (AERI)– 3-19.2 m (1 cm-1 resolution)– 6-min resolution (20-30 sec possible for COPS)– 1.3 degree field-of-view

Clear Sky AERI SpectraClear Sky AERI Spectra

Surface Shortwave RadiationSurface Shortwave Radiation

Downwelling and Upwelling Total– 0.3-3.0 m global hemispheric irradiance– Unshaded pyranometer

Downwelling Diffuse– 0.3-3.0 m global hemispheric irradiance– shaded pyranometer

Direct-Normal– 0.3-3.0 m– Tracking pyroheliometer with 5.7 degree field-of-

view

Surface Shortwave RadiationSurface Shortwave Radiation Multi-filter rotating shadowband radiometer

(MFRSR)– Total, Diffuse, and Direct-Normal – 6 channels @ 10-nm width

Wavelength (nm) Application

415 aerosol

500 aerosol, ozone

615 aerosol, ozone

673 aerosol, ozone

870 aerosol

940 water vapor

Surface Longwave RadiationSurface Longwave Radiation

Downwelling and upwelling Total– 4.0-50 m global hemispheric irradiance– shaded pyrgeometer

Surface Broadband SummarySurface Broadband SummaryMeasurement Radiometer

ModelUncertainty

Direct Normal Beam NIP ±3.0%

or 4.0 Wm-2

Diffuse Horizontal (sky) PSP ±6.0%

or 20.0 Wm-2

Downwelling Shortwave (global)

PSP ±6.0%

or 10.0 Wm-2

Downwelling Longwave (atmospheric)

PIR ±2.5%

or 4.0 Wm-2

Upwelling Shortwave (Reflected)

PSP ±6.0%

or 15.0 Wm-2

Upwelling Longwave (terrestrial)

PIR ±2.5%

or 4.0 Wm-2

Total Sky Imager (TSI)Total Sky Imager (TSI)

TSI Boundary Layer Cloud Cirrus

RV Ron BrownCentral Pacific

AOT=0.08

RV Ron BrownSea of JapanAOT=0.98

AMFNiamey, NigerAOT=2.5-3.0

Interesting Sky ImagesInteresting Sky Images

Surface Aerosol SystemSurface Aerosol System Two 3-Wavelength Nephelometers

– 450, 550, 700 nm– One humidified and one dry– Total angular scattering and hemispheric backscattering

coefficients (90º-170º)– Scattering coefficients as a function of RH

Particle Soot Absorption Photometer (PSAP)– Absorption coefficient at 550 nm– Extinction coefficient when combined with nephelometer

measurements Cloud Condensation Nuclei Counter (CCN)

– 7 supersaturation set points ranging from 0.18-1.37– 30-minutes to span range– Measures CN and CCN

How it really looked during

MASRAD

AMF AOSInstruments

denoted AOS AOS

CCN

PNNLSMPS

PNNLCCN

UCDavisSizers

CVIinlet

AOSPSAPCPC

CVIPSAPhygroCPC

CVINeph

UFCN

AO

SN

ephs

BN

L S

MP

SN

AS

A C

aden

zaLi

dar

CVITRAC

AOSTRAC

PNNLAMS

AOSinlet

http://www.cmdl.noaa.gov/gallery/AMF

CVIpumps

AOSpumps

aerosoltrailer

hum

idifi

erUPS

Surface MeteorologySurface Meteorology

Standard variables– T, RH, P, winds (10-m for COPS)– Rainfall (optical rain gauge)– Present Weather

Optical measurement of visibility Fog detection

Latent, sensible, and carbon fluxes– Eddy correlation (2-m height)

New Additions to AMFNew Additions to AMF

CIMEL Sun Photometer – Before COPS

Possibly ARM’s new 90 / 150 GHz microwave radiometer

Data, Data, DataData, Data, Data AMF data are generally available within a day or two

from the ARM data archive (www.archive.arm.gov)– True for all ARM data– Data quality documented afterwards– Reprocessing is occasionally required

Data are open to all investigators Some data streams can be accessed in real-time, if

needed (i.e., radiosonde profiles) Recommendation: talk with Mark Miller and/or the

“instrument mentors” when you start using various ARM datastreams…

ARM tracks data users (# of requests, # of different datastreams, etc.) – this is an important metric

SummarySummary

AMF has most of the instrumentation used at the various ARM fixed sites

Supplements the instrumentation provided by our European colleagues

Excited about COPS, and looking forward to a fruitful experiment!