This README file describes the format of the 6-channel Ames Airborne Tracking 
Sunphotometer (AATS-6) H2O vertical profile results obtained during ACE-Asia aboard
the NCAR C-130.

The filenaming convention is

RFxx_A6_ddMonyy_hhmmUT_pw.asc

where xx=flightnumber, A6 (for AATS-6), date (on which file was started), start time of profile (UTC hhmm) "p" for profile,
and "w" for water.
 
Times can be larger than 24UTC if the file was started on the previous day. 

The data are Q/A-ed and obstructions by clouds or aircraft structures have been removed. The current version (4.0) uses the RAF-distributed reference altitudes. 
For comparison with other investigators' data we recommend that their data be projected on the RAF reference altitudes as well. The curent version of AATS-6 data 
is also corrected for diffuse light entering AATS-6's field of view. For an explanation of these corrections, please see the statement posted at 
http://geo.arc.nasa.gov/sgg/ACE-Asia/Data_Plots/diffuse.html. 

The exact format is described in the header of each file.


The retrieval algorithms are described in:

Russell, P. B., J. M. Livingston, E. G. Dutton, R. F. Puschel, J. A. Reagan,
T. E. Defoor, M. A. Box, D. Allen, P. Pilewski, B. M. Herman, S. A. Kinne, and 
D. J. Hofmann, 1993: "Pinatubo and Pre-Pinatubo Optical-Depth Spectra: Mauna Loa
Measurements, Comparisons, Inferred Particle Size Distributions, Radiative Effects,
and Relationsship to Lidar Data". Journal of Geophysical Research, Vol. 98, No. D12,
22'969-22'985.

Schmid B., C. Mätzler, A. Heimo, and N. Kämpfer, 1997: Retrieval of Optical Depth
and Size Distribution of Tropospheric and Stratospheric Aerosols by Means of Sun 
Photometry. IEEE Transactions on Geoscience and Remote Sensing, Vol 35, No. 1, 172-182.

Schmid, B., J. M. Livingston, P. B. Russell, P. A. Durkee, H. H. Jonsson, D. R. Collins,
R. C. Flagan, J. H. Seinfeld, S. Gassó, D. A. Hegg, E. Öström, K. J. Noone, E. J. Welton,
K. J. Voss, H. R. Gordon, P. Formenti, and M. O. Andreae, Clear sky closure studies of
lower tropospheric aerosol and water vapor during ACE 2 using airborne sunphotometer,
airborne in-situ, space-borne, and ground-based measurements, Tellus, B 52, 568-593, 2000.

Schmid B., J.J. Michalsky, D.W. Slater, J.C. Barnard, R.N. Halthore, J.C. Liljegren,
B.N. Holben, T.F. Eck, J.M. Livingston, P.B. Russell, T. Ingold, and I. Slutsker.
Comparison of columnar water-vapor measurements from solar transmittance methods.
Applied Optics, Vol. 40, No. 12, 1886-1896 (2001).



Point of contact:

Jens Redemann/Beat Schmid/Phil Russell/John Livingston
NASA Ames Research Center
MS 245-5
Moffett Field, CA 94035-1000

Phone: (805) 658-2637
Fax:   (805) 658-2637
e-mail: jredemann@mail.arc.nasa.gov

Check out our Web site http://geo.arc.nasa.gov/sgg/AATS-website/ regularly for updates.