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Siberian smoke over Oklahoma as seen from Twin Otter on May 27, 2003 Photo courtesy of Roy Woods

How well can we measure the vertical profile of tropospheric aerosol extinction? B. Schmid, R. Ferrare, C. Flynn, R. Elleman, D. Covert, A. Strawa, E. Welton, D. Turner, H. Jonsson, J. Redemann, J. Eilers, K. Ricci, A. Hallar, M. Clayton, J. Michalsky, A. Smirnov, B. Holben, J. Barnard.

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Siberian smoke over Oklahoma as seen from Twin Otter on May 27, 2003 Photo courtesy of Roy Woods

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  1. How well can we measure the vertical profile of tropospheric aerosol extinction? B. Schmid, R. Ferrare, C. Flynn, R. Elleman, D. Covert, A. Strawa, E. Welton, D. Turner, H. Jonsson, J. Redemann, J. Eilers, K. Ricci, A. Hallar, M. Clayton, J. Michalsky, A. Smirnov, B. Holben, J. Barnard Siberian smoke over Oklahoma as seen from Twin Otter on May 27, 2003 Photo courtesy of Roy Woods Paper submitted to AIOP JGR special issue, Feb 3, 2005

  2. ARM Aerosol IOP – May 2003 CIRPAS Twin Otter Focus on data obtained in vertical profiles over SGP CF Altitudes: ~90 – 5600 m

  3. How do we measure the vertical profile of aerosol extinction? unaltered aerosol @ ambient concentration @ thermodynamic state • Airborne: • Nephelometer+PSAP • Cavity-Ring-Down (Cadenza) • Sunphotometry (AATS-14) • Ground based: • Raman Lidar (CARL) • MPLNET • MPLARM Photo courtesy Yin-Nan Lee, BNL

  4. NASA Ames Airborne Tracking SunphotometerAATS-14: 354-2139 nmAerosol Optical Depth and H2O columnAerosol Extinction and H2O density in suitable profiles

  5. Extinction comparisons in previous field campaigns TARFOX, 1996 ACE-Asia, 2001 CLAMS, 2001 ACE-2, 1997 ARM Aerosol IOP, 2003 PRIDE, 2000 SAFARI, 2000

  6. Conclusions: Current Effort • Looking at results from 6 field campaigns, airborne in-situ measurements of extinction tend to be biased slightly low (mean of 17%) when compared to airborne sunphotometer extinction. • Lidar measurements of extinction from 6 field campaigns show no or positive biases. • Systematic errors in measuring ambient aerosol extinction profiles with current state-of-the-art instrumentation are 15-20% in the visible. Random errors are considerably larger. • Raman Lidar measurements in AIOP biased high (29 Mm-1  UV 54%). We expect better agreement from a “healthier” Raman lidar.

  7. Summary of Achievements: Current ARM ST EffortVertically resolved aerosol optical properties over the ARM SGP sitePI: Schmid, Co-I: Pilewskie, Strawa, Russell, Bergstrom, Redemann • PI instrumental in planning and executing AIOP. Platform Scientist Twin Otter. • Twin Otter data used in 10 publications for AIOP JGR special issue. • PI and Co-I’s have contributed directly to 7 of the 10 publications: • Aerosol Indirect Effect Studies at Southern Great Plains during the May 2003 Intensive Operations Period. Feingold et al. (with Pilewskie). • Comparison of methods for deriving aerosol asymmetry parameter. Andrews et al. (with Schmid) • Evaluation of Daytime Measurements of Aerosols and Water Vapor made by an Operational Raman Lidar over the Southern Great Plains. Ferrare et al. (with Schmid, Redemann), • How well can we measure the vertical profile of aerosol extinction? Schmid et al. (with Strawa, Redemann) • A comparison of aerosol optical properties obtained from in-situ measurements and retrieved from Sun and sky radiance observations during the May 2003 ARM aerosol intensive observation period. Ricchiazzi et al. (with Schmid) • Comparison of In-Situ and Remote Aerosol Optical Property Measurements During the DOE Aerosol IOP. Strawa et al. (with Schmid), close to submission, • Elevated injection height, long-range transport, and evolution of a Siberian forest fire smoke plume. Colarco et al. (with Schmid) close to submission

  8. CRF Raman Lidar, since 1997 Unattended, 24/7, H2O, aerosols Goal: 10 yr CDR • Aerosol Extinction profiles l=355 nm • Unnoticed loss of sensitivity leading up to AIOP • Automated algorithms had to be modified to reduce impact of sensitivity loss, but 54% bias remains • Major upgrades/mods were performed after AIOP resulting in significantly better performance than during any other time. Photo courtesy Yin-Nan Lee, BNL

  9. Micro Pulse Lidars • Aerosol Extinction profiles l=523 nm are a new product in b-stage (C. Flynn) • First validation in AIOP over SGP • Would like larger dataset for validation • Deployed at: • SGP • NSA (pol.) • AMF (pol.) • TWP Manus • TWP Nauru • TWP Darwin • & several spares

  10. Proposed SGP Lidar Validation IOP • Goal: Validate CARL, MPL and IAP Aerosol Extinction Profiles • AATS-14 aboard a profiling aircraft • 10 days, 20 flight hours • Profiles 300 – 23,000 ft altitude • Sep 2005, IOP (after NASA CALIPSO validation experiment) • Dec. 10, 2004 Endorsed by AWG • Feb. 28, 2005 Pre-proposal submitted • Mar. 18, 2005 (?) Pre-proposal approved AATS-14 on Sky Research J-31

  11. Proposed future ST effortsTask 1: Aerosol Best Estimate (ABE) Product – Sensitivity Study • Aerosol extinction, wo, g at all times and heights above all ACRF • Inputs for BBHRP & Shortwave QME • Currently for SGP only • How much detail is required? (varies by site?  use of resources) • Collaborators (Turner, Ferrare, Mlawer)

  12. CM22 SSFR CG4 Proposed future ST effortsTask 2: Vertically resolved aerosol and cloud radiative properties over SGP • Radiometric AIOP aircraft data set underused • Observation-based quantification of effect of aerosol & clouds on radiation • Radiative closure (in-situ  RTM  radiation) • BBHRP test cases • Collaborators: Pilewskie, Mlawer

  13. Proposed future ST effortsTask 3: • Integrated analysis of data from proposed Lidar Validation IOP (if approved before submission of full ST proposal) • Collaborators: Ferrare, Turner, Flynn

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