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

1. Overview of the Atmospheric Radiation Measurement (ARM) Program’s Mobile Facility (AMF) Dave Turner University of Wisconsin – Madison COPS Workshop 10-11 April 2006 Hohenheim, Germany

2. The Real People Behind the AMF • Head Scientist: Mark Miller • Team Members: Mary Jane Bartholomew, Larry Jones, Kim Nitschke, Doug Sisterson • Chief Engineer: Kevin Widener • Program Manager: Wanda Ferrell

3. The ARM Mobile FacilityInitially Deployed in 2005 Pt. Reyes, California Niamey, Niger, Africa

4. Charter • 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

5. Site 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

6. Active and Passive Cloud Remote 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

7. 3.2 mm Cloud Radar Doppler Velocity from Niamey, Niger “First light”

8. Active and Passive Cloud 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

9. MPL Example From Niamey 20 15 Backscatter (arb units) Height (km) 10 LIQUID CLOUDS 5 Biomass Burning Dust 0 1200 2400 0000 Time (UTC)

10. Active and Passive Cloud 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

11. ARM’s MWRs Clear Sky Microwave Optical Depth Spectrum

12. Active and Passive Cloud 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 mm (1 cm-1 resolution) • 6-min resolution (20-30 sec possible for COPS) • 1.3 degree field-of-view

13. Clear Sky AERI Spectra

14. Surface Shortwave Radiation • Downwelling and Upwelling Total • 0.3-3.0mm global hemispheric irradiance • Unshaded pyranometer • Downwelling Diffuse • 0.3-3.0mm global hemispheric irradiance • shaded pyranometer • Direct-Normal • 0.3-3.0mm • Tracking pyroheliometer with 5.7 degree field-of-view

15. Surface Shortwave Radiation • Multi-filter rotating shadowband radiometer (MFRSR) • Total, Diffuse, and Direct-Normal • 6 channels @ 10-nm width

16. Surface Longwave Radiation • Downwelling and upwelling Total • 4.0-50mm global hemispheric irradiance • shaded pyrgeometer

17. Surface Broadband Summary

18. Total Sky Imager (TSI) TSI Boundary Layer Cloud Cirrus

19. Interesting Sky Images RV Ron Brown Central Pacific AOT=0.08 RV Ron Brown Sea of Japan AOT=0.98 AMF Niamey, Niger AOT=2.5-3.0

20. Surface 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

21. CVI inlet How it really looked during MASRAD AMF AOS Instruments denoted AOS UCDavis Sizers AOS inlet CVI pumps aerosol trailer AOS pumps UFCN AOS TRAC AOS PSAP CPC Lidar AOS CCN CVI Neph CVI TRAC PNNLSMPS NASA Cadenza BNL SMPS AOSNephs humidifier CVI PSAP hygro CPC PNNLCCN PNNLAMS UPS http://www.cmdl.noaa.gov/gallery/AMF

22. Surface 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)

23. New Additions to AMF • CIMEL Sun Photometer • Before COPS • Possibly ARM’s new 90 / 150 GHz microwave radiometer

24. Data, 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

25. Summary • 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!