National Center for Atmospheric Research

Atmospheric Technology Division

RESEARCH AVIATION FACILITY P.O. Box 3000 Boulder, Colorado 80307-3000

Telephone: (303) 497-1030 Facsimile: (303) 497-1092 Internet:

15 April 1996


Dr. Barry Huebert

Department of Oceanography

1000 Pope Road

University of Hawaii

Honolulu, HI 96822

Dear Barry:

Enclosed is the final documentation for the airborne measurements made by the EC-130Q during the First Aerosol Characterization Experiment (ACE -1) from 31 October to 22 December 1995. The LRT (1 sample per second) data set is now available through the UCAR Office of Field Project Support. The HRT (25 sample per second) data set will only be maintained on the NCAR SCD Mass Store System (MSS) due its great size. Access will be available through the normal channels.

I want to point out that both raw and processed data are backed up on the MSS which has proven to be a reliable archive.

Several items enclosed with this letter should be considered part of the data package and are important to your analysis of the flight data. A copy of all of this information will also be available in electronic form through the UCAR OFPS ACE-1 archive. They are:

1. Mass Store Bitfile Logs: A complete list of information on the processed data files for both LRT and HRT data

2. Research Flight Reports: Flight Operations summaries including general information on arrival & departure times and data-recording intervals

3. Data Quality Report: Review of the general limitations of the data set along with flight-by-flight documentation of questionable data

4. Summary of IRS performance: includes the Inertial Reference System's final terminal position and ground speed errors for each flight

5. Exerpt from Bulletin No. 9: RAF documentation describing the algorithms used during the data processing to calculate the derived measurements

6. Bulletin No. 23: RAF documentation describing air motion measurement techniques on the NCAR research aircraft (This Bulletin also discusses the in-flight calibration maneuvers, their purpose and interpretation.)

7. Aircraft Research Instrumentation Configuration: Sensors, signal conditioners, filters and sample rates

8. Summary of Project Calibrations: Note that the calibration coefficients and reference sensors used for all derived measurements are also identified in the netCDF header of each data file.

9. List of parameters provided by the final data processing

10. Processed Data Description

a) LRT (averaged, 1 sample per second) netCDF data: will only be available on-line from the official UCAR OFPS archive
b) HRT (25 sample per second) netCDF data: will be available on the MSS at a later date

11. Video Film Log Documentation on VCR tape cassettes recorded during the research flights

12. Raw ADS Tape Summary: Information about all the raw ADS 8mm magnetic tapes recorded aboard the EC-130Q (N130AR)

13. Mass Store Bitfile Log for Stripped PMS-2D Data: A complete list of information on the unprocessed PMS-2D data stripped from the raw ADS data tapes, put into UNIX binary files and archived on the MSS

It is essential that we receive from users, such as yourself, an evaluation of the support we have provided, beginning with the planning phase and continuing through the field phase on to the delivery of and finally the analysis by the user of the data. This feedback activity is carried out through the office of Dr. David Carlson, the Director of the Atmospheric Technology Division. It begins with a phone call from David--by now he may already have contacted you, and continues with a letter from him several months after you have received the data. We believe this procedure provides the user with a convenient path for presenting us with constructive criticism.

As you proceed with the analysis of the data, you may have questions, encounter problems, or uncover discrepancies or other aspects of the data that may be of interest to the RAF and to other users. Specific discrepancies or errors in the data should be brought to the attention of Allen Schanot, the Project Manager.

I hope that the support of your research by the Aviation Facility has been satisfactory. It has been our pleasure to serve you. If I can be of further help, please do not hesitate to call.


Paul Herzegh, Manager

Research Aviation Facility


cc: D. Carlson