Validation of aerosol extinction and water vapor profiles from routine Atmospheric Radiation Measurement Climate Research Facility measurements

Journal Article · Thu Nov 26 04:00:00 EST 2009 · Journal of Geophysical Research - Atmospheres

DOI:https://doi.org/10.1029/2009JD012682· OSTI ID:969170

Schmid, Beat ^[1]; Flynn, Connor J. ^[1]; Newsom, Rob K. ^[1]; Turner, David D. ^[2]; Ferrare, Richard ^[3]; Clayton, Marian F. ^[4]; Andrews, Elisabeth ^[5]; Ogren, John A. ^[6]; Johnson, Roy R. ^[7]; Russell, P. B. ^[7]; Gore, W. ^[7]; Dominguez, Roseanne ^[8]

---

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Univ. of Wisconsin, Madison, WI (United States)
3. NASA Langley Research Center, Hampton, VA (United States)
4. SSAI/ NASA Langley Research Center, Hampton, VA (United States)
5. Univ. of Colorado, Boulder, CO (United States)
6. NOAA/ESRL, Boulder, CO (United States)
7. NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States)
8. Univ. of California, Santa Cruz, CA (United States); NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States)

The accuracy with which vertical profiles of aerosol extinction σ_ep(λ) can be retrieved from ARM Climate Research Facility (ACRF) routine measurements was assessed using data from two airborne field campaigns, the ARM Aerosol Intensive Operation Period (AIOP, May 2003), and the Aerosol Lidar Validation Experiment (ALIVE, September 2005). This assessment pertains to the aerosol at its ambient concentration and thermodynamic state (i.e. σ_ep(λ) either free of or corrected for sampling artifacts) and includes the following ACRF routine methods: Raman Lidar, Micro Pulse Lidar (MPL) and in-situ aerosol profiles (IAP) with a small aircraft. Profiles of aerosol optical depth τp(λ), from which the profiles of σep(λ)are derived through vertical differentiation, were measured by the NASA Ames Airborne Tracking 14-channel Sunphotometer (AATS-14); these data were used as truth in this evaluation. The ACRF IAP σ_ep(550 nm) were lower by 16% (during AIOP) and higher by 10% (during ALIVE) when compared to AATS-14. The ACRF MPL σ_ep(523 nm) were higher by 24% (AIOP) and 19%-21% (ALIVE) compared to AATS-14 but the correlation improved significantly during ALIVE. In the AIOP a second MPL operated by NASA showed a smaller positive bias (13%) with respect to AATS-14. The ACRF Raman Lidar σ_ep(355 nm) were higher by 54% (AIOP) and higher by 6% (ALIVE) compared to AATS-14. The large bias in AIOP stemmed from a gradual loss of the sensitivity of the Raman Lidar starting about the end of 2001 going unnoticed until after AIOP. A major refurbishment and upgrade of the instrument and improvements to a data-processing algorithm led to the significant improvement and very small bias in ALIVE. Finally we find that during ALIVE the Raman Lidar water vapor densities ρw are higher by 8% when compared to AATS-14, whereas comparisons between AATS-14 and in-situ measured ρw aboard two different aircraft showed small negative biases (0 to -3%).

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 969170
• Report Number(s): PNNL-SA--67186; KP1701000
• Journal Information: Journal of Geophysical Research - Atmospheres, Journal Name: Journal of Geophysical Research - Atmospheres Vol. 114; ISSN 0747-7309
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
54 ENVIRONMENTAL SCIENCES
ACCURACY
AEROSOLS
ALGORITHMS
DATA COVARIANCES
OPTICAL RADAR
SENSITIVITY
VALIDATION
WATER VAPOR