BAMEX Aircraft: NOAA P-3 Navigation, State Parameter, and Microphysics Data - NetCDF Format (UCAR/JOSS) 1.0 General Information The BAMEX Aircraft: P-3 Meteorology Navigation and State Parameters dataset in network common data form (netCDF) is one of several datasets provided by the University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS) in support of the Bow Echo and MCV EXperiment (BAMEX) project. The data were collected by the National Oceanic and Atmospheric Administration Aircraft Operations Center (NOAA/AOC) P-3 aircraft and converted to netCDF format by UCAR/JOSS. 2.0 Data Contact Jose Meitin (meitin@ucar.edu) 3.0 Data and Format Information 3.1 Detailed Data Description This dataset is comprised of binary data files in netCDF format. These data are stored one flight per file and labeled by flight number. The flight number consists of the year, month, and day of the flight presented as YYMMDD, followed by a one-letter designator indicating which P-3 the data came from. For example, flight number 030111i indicates the data was collected aboard the NOAA43 P-3 on Jan 11, 2003. See table 3.1.1 for a complete list of possible designators. Note that only the NOAA42 was flown during BAMEX, so all data files have names like YYMMDDh. Table 3.1.1 - aircraft designators Aircraft Designator Notes -------------- ---------- --------- NOAA42 (N42RF) H First P3 NOAA43 (N43RF) I Second P3 The netCDF formatted data were extracted by UCAR/JOSS from binary data files provided by NOAA/AOC in NOAA/AOC Standard Tape Format. The binary data files contain 6 record types. For a description of these data types, see the documentation for the codiac dataset "BAMEX Aircraft: P-3 Meteorology Navigation and State Parameters - Standard Tape Format (NOAA/AOC)". The netCDF files provided here contain all data from type 1 (header), type 3 (converted data transformation), type 5 (converted/derived data), and type 6 (trailer) records. Data from record types two (the original data transformation record) and four (original data record containing raw data from the AOC slow tape) are NOT included in this dataset. Note on flight 030618h-a: The Standard Tape Format file for this flight is corrupt approx 1/4 of the way into the flight. The purpose of this mission was a flight-level intercomparison of thermodynamic and wind parameters measured by the NOAA P-3 and NRL P-3 under weak ~northerly flow conditions. (See the NOAA P-3 mission summary report in the BAMEX field catalog.) As the NRL's scientific INS system failed for this flight, the scientific interest in the NOAA data is minimal. Thus, no attempt has been made to recover the NOAA data. 3.2 Detailed Format Description See http://www.unidata.ucar.edu/packages/netcdf for a description of the netCDF format. While netCDF is intended for "self-documenting data", it is often necessary for data writers and readers to agree upon naming conventions and the meaning of dimension names, variable names, attributes, and representations for discipline-specific data structures. These agreements are written up as human readable documents called netCDF conventions. This dataset follows the NCAR-RAF netCDF conventions which can be found at http://raf.atd.ucar.edu/Software/netCDF.html. However, when these conventions contradict the more recent Writing NetCDF Files: Best Practices document at http://www.unidata.ucar.edu/staff/russ/netcdf/BestPractices.html the Best Practices document takes precedent. Note that the variable names and descriptions given in the NOAA/AOC Standard Tape Format documentation for BAMEX have been preserved in the netCDF formatted data. Error indicators, when available, are included in the netCDF file as independent variables with the extension _ERR added to the name of the variable they are describing. For example, error information for the netCDF variable LAT is stored in the netCDF variable LAT_ERR. Unit naming conventions are taken from the UDUNITS package: http://www.unidata.ucar.edu/packages/udunits/ This data uses the following angle conventions. These are the same conventions used in the C-130 data. a) pitch: positive is nose up b) roll: positive is right wing down (facing forward) c) attack: positive has the airstream coming from below the aircraft's center line d) sideslip: positive has the airstream coming from the right side of the aircraft (facing forward) e) drift angle: positive has the ground track to the right of true heading For more information, refer to RAF Bulletin No. 23, Fig. 2.1 available on line: http://raf.atd.ucar.edu/Bulletins/bulletin23.html This data uses the following velocity conventions. These are the same conventions used in the C-130 data. a) U, E and X are E/W components (positive is to the east) b) V, N and Y are N/S components (positive is to the north) c) W is vertical component (positive is up, away from earth's surface) For more information, refer to RAF Bulletin No. 9 available on line: http://raf.atd.ucar.edu/Bulletins/b9appdx_B.html#WINDS 3.3 Data Remarks Missing values are represented as -32767.f. The _FillValue attribute is used to indicate this, as the MissingValue attribute is deprecated. Times are given both as an offset from the basetime of seconds since Jan 1, 1970, and as a year, month, day, hour, minute, and second. All times are in UTC. 4.0 Quality Control No quality control has been performed on this data by the University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS) 5.0 References NCAR/RAF, cited 2003: NCAR-RAF netCDF Conventions Version 1.1. [Available on-line from http://raf.atd.ucar.edu/Software/netCDF.html] NCAR/RAF, cited 2003: RAF Bulletin No. 23, Fig. 2.1 [Available on-line from http://raf.atd.ucar.edu/Bulletins/bulletin23.html] NCAR/RAF, cited 2003: RAF Bulletin No. 9 [Available on-line from http://raf.atd.ucar.edu/Bulletins/b9appdx_B.html#WINDS] NOAA/AOC, cited 2003: aoc.noaa.gov website [Available online from http://www.aoc.noaa.gov/aircraft_lockheed.htm] UCAR/JOSS, cited 2003: Documentation for the dataset "SALLJEX Aircraft: P-3 Meteorology Navigation and State Parameters - Standard Tape Format (NOAA/AOC)". [Available on-line from http://www.joss.ucar.edu/cgi-bin/codiac/dss?83.008] UCAR/Unidata, cited 2003: UDUNITS, A library for manipulating units of physical quantities. [Available on-line from http://www.unidata.ucar.edu/packages/udunits/ UCAR/Unidata, cited 2003: Unidata NetCDF. [Available on-line from http://www.unidata.ucar.edu/packages/netcdf] UCAR/Unidata, cited 2003: Writing NetCDF Files: Best Practices. [Available on-line from http://www.unidata.ucar.edu/staff/russ/netcdf/BestPractices.html]