Evaluation of Daytime measurements of Aerosols and Water Vapor made by an Operational Raman Lidar over the Southern Great Plains
Goldsmith, John E.M.
MetadataShow full item record
Raman lidar water vapor and aerosol extinction profiles acquired during the daytime over the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in northern Oklahoma (36.606 N, 97.50 W, 315 m) are evaluated using profiles measured by in situ and remote sensing instruments deployed during the May 2003 Aerosol Intensive Operations Period (IOP). The automated algorithms used to derive these profiles from the Raman lidar data were first modified to reduce the adverse effects associated with a general loss of sensitivity of the Raman lidar since early 2002. The Raman lidar water vapor measurements, which are calibrated to match precipitable water vapor (PWV) derived from coincident microwave radiometer (MWR) measurements were, on average, 5–10% (0.3–0.6 g/m3) higher than the other measurements. Some of this difference is due to out-of-date line parameters that were subsequently updated in the MWR PWV retrievals. The Raman lidar aerosol extinction measurements were, on average, about 0.03 km 1 higher than aerosol measurements derived from airborne Sun photometer measurements of aerosol optical thickness and in situ measurements of aerosol scattering and absorption. This bias, which was about 50% of the mean aerosol extinction measured during this IOP, decreased to about 10% when aerosol extinction comparisons were restricted to aerosol extinction values larger than 0.15 km 1. The lidar measurements of the aerosol extinction/backscatter ratio and airborne Sun photometer measurements of the aerosol optical thickness were used along with in situ measurements of the aerosol size distribution to retrieve estimates of the aerosol single scattering albedo (wo) and the effective complex refractive index. Retrieved values of wo ranged from (0.91–0.98) and were in generally good agreement with wo derived from airborne in situ measurements of scattering and absorption. Elevated aerosol layers located between about 2.6 and 3.6 km were observed by the Raman lidar on 25 and 27 May. The airborne measurements and lidar retrievals indicated that these layers, which were likely smoke produced by Siberian forest fires, were primarily composed of relatively large particles (reff 0.23 mm) and that the layers were relatively nonabsorbing (wo 0.96–0.98). Preliminary results show that major modifications that were made to the Raman lidar system during 2004 have dramatically improved the sensitivity in the aerosol and water vapor channels and reduced random errors in the aerosol scattering ratio and water vapor retrievals by an order of magnitude.
Journal of Geophysical Research, Vol. 111, D05S08The article of record as published may be located at http://dx.doi.org/10.1029/2005JD005836
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Column closure studies of lower tropospheric aerosol and water vapor during ACE-Asia using airborne Sun photometer and airborne in situ and ship-based lidar measurements Schmid, B.; Hegg, D.A.; Wang, J.; Bates, D.; Redemann, J.; Russell, P.B.; Livingston, J.M.; Jonsson, H.H.; Welton, E.J.; Seinfled, J.H.; Flagan, R.C.; Covert, D.S.; Dubovik, O.; Jefferson, A. (2003);We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne Sun photometry and derived from airborne in situ and ship-based lidar measurements during the April 2001 ...
Collins, D.R.; Jonsson, H.H.; Seinfeld, J.H.; Flagan, R.C.; Gasso, S.; Hegg, D.A.; Russell, P.B.; Schmid, B.; Livingston, J.M.; Ostrom, E.; Noone, K.J. (2000);As part of the second Aerosol Characterization Experiment (ACE-2) during June and July of 1997, aerosol-size distributions were measured on board the CIRPAS Pelican aircraft through the use of a DMA and 2 OPCs. During ...
Gao, Song; Hegg, Dean A.; Jonsson, Haflidi (2003);During the ACE-Asia field campaign, 41 aerosol filter samples were obtained by airborne sampling over the ocean to the north, south and west of Japan, generally under conditions of outflow from the Asian continent. These ...