LASE_AFWEX Readme 1.0 Introduction This file contains information about the sample read software and the (LASE) ARM-FIRE Water Vapor Experiment [AFWEX] data in the Gaines-Hipskind formatting convention. The LASE_AFWEX data set includes two types of files, one containing atmospheric scattering ratio profiles and the other containing water vapor concentration profiles. The LASE_AFWEX data files are stored in ASCII using Gaines-Hipskind [GH] Data Archive Format and can be read with the DAAC-provided read software. Additional information about the LASE data sets can be found in the LASE project and data set Guide documents at the Langley DAAC: http://eosweb.larc.nasa.gov AFWEX was conducted from November 27-December 15, 2000 at the ARM Southern Great Plains Cloud and Radiation Testbed (CART) Site site in Lamont, Oklahoma. The goals of the mission were to characterize and improve the accuracy of water vapor measurements under a wide variety of conditions. The AFWEX home page is http://www.arm.gov/docs/iops/2000/sgp2000afwex/afwex.html. Documents describing the Gaines-Hipskind Data Archive Format are available from the DAAC at http://eosweb.larc.nasa.gov/PRODOCS/lase/table_lase.html This Readme file includes five other sections: Section 2.0 - describes the available read software. Section 3.0 - discusses how to create an executable program from read software source code. Section 4.0 - demonstrates how to invoke the executable program. Section 5.0 - provides general information for the data set. Section 6.0 - provides more detailed implementation notes. If there are questions about using the LASE sample read software, please contact the Langley Science, User and Data Services (SUDS) office. The SUDS office may be reached by E-Mail: larc@eos.nasa.gov, by telephone at (757)864-8656, or by FAX at (757)864-8807. The SUDS mailing address is: Langley DAAC Science, User and Data Services Office NASA Langley Research Center Mail Stop 157D, 2 S. Wright St. Hampton, VA 23681-2199 USA 2.0 Read Software Files Currently, there is one sample read program which works with all Gaines-Hipskind formatted LASE data sets, read_lase_gh.c. It is written in ANSI C. This program has been tested on the following computers and operating systems: Computer Operating System ------------------- ---------------- Sun Sparc Solaris 2.5 Sun4 SunOS 4.1.3 SGI Origin 2000 IRIX 6.4 This program is written as an example of how to read the LASE_AFWEX data. As delivered, it reads in and writes to the screen the file header information followed by each profile's data values. 3.0 Creating Executable Program Files 3.1 Create with C compiler To compile the program, use the command for the ANSI C compiler. The command varies slightly among operating systems. On Sun Solaris, SGI and DEC Alpha systems the command is: % cc -o read_lase_gh read_lase_gh.c On SunOS systems, use acc in place of cc in the preceding example. On HP-UX systems, the appropriate compiler command is c89 rather than cc. If the appropriate compile command is not found on your system, check to be sure that your PATH environment variable includes the directory that contains the compiler or specify the entire path to the compiler in your command. This compile command creates an executable program file named read_lase_gh. 4.0 Invoking Read Software 4.1 Running the executable version of the LASE_AFWEX Read C Program The executable version of the LASE_AFWEX read C program optionally accepts one command line argument, the name of the LASE data file, e.g. read_lase_gh lase_afwex_aer_20001127 If the file is not in the directory from which the program is invoked, it is necessary to specify the full directory path to the data file along with its name. The program allows for file names up to 50 characters long. If you have renamed the file to a longer name (including the path), you can extend the maximum allowed length by changing the value assigned to the parameter MAX_FILENAME in the #define statement near the beginning of the source code file. Note that the value specified should be the maximum length needed + 1. If the name of the LASE_AFWEX file is not specified at the command line when the program is executed, the user is prompted by the program to enter the file name. A sample of the interactive program execution is provided in Section 6.0. 5.0 Data Set Information 5.1 LASE_AFWEX Data Set LONG NAME FOR THIS DATA SET: Lidar Atmospheric Sensing Experiment data measurements taken during the ARM-FIRE Water Vapor Experiment FILE NAMING CONVENTION: LASE_AFWEX data set files are prefixed with "lase_afwex_" to indicate they belong to this data set. This is followed by a three character designation of the type of profile stored in the file, 'aer' for atmospheric scattering ratio data and 'h2o' for water vapor concentration. The last characters preceeded by a dash are digits indicating the date by year month day. Here are two example file names: lase_afwex_aer_20001127 atmospheric scattering ratio profiles from flight taken on November 27, 2000 lase_afwex_h2o_20001127 water vapor concentration profiles from flight taken on November 27, 2000 VARIABLES: The data is recorded in the Gaines-Hipskind format. This format is based upon the concept of an exchange file to convey some measured, calculated, or otherwise derived quantity, which is called the PRIMARY variable. There may be some ancillary information concerning the measurement, calculation, or interpretation of the PRIMARY variables. These secondary quantities are called AUXILIARY variables. Both PRIMARY and AUXILIARY variables are considered as dependent variables, and are always recorded with reference to at least one INDEPENDENT variable. INDEPENDENT variables can be time, spatial coordinates, index values, or any other quantity that can be used to uniquely identify a particular PRIMARY variable value. See section 6.0 for an example of how the data was decoded and written to output. 6.0 Implementation Notes This section gives a brief explanation of how to run the sample read software. 6.1 read_lase_gh C Program The read_lase_gh C program can be used to read any of the Gaines_Hipskind data set files. The following is a sample session showing compilation and execution of the read_lase_gh program on the machine named darrin. darrin 3% cc -o read_lase_gh read_lase_gh.c darrin 4% read_lase_gh ********************************************************** LASE_SOLVE READ PROGRAM Version 1.0 20 DEC 2000 This program reads the LASE SOLVE/AFWEX data in the Gaines-Hipskind formatting convention. The input file name is built according to the naming convention formed by the Langley DAAC. Currently the input file name is expected to be no more than 50 characters in length. If you have changed the name of the input file to greater than 50 characters, you will need to modify this program, changing the value of the MAX_FILENAME parameter in the #define statement near the beginning of the file to be at least the maximum length needed + 1. All data files are assumed to be in the current working directory. If the files are located in another directory, please be sure to include the complete path with the file name. The program also accepts input by way of the link command: example ln -s /fs1/LASE/SOLVE/archive_data/lase_solve_aer_nadir_19991130 LASE_LINK This command will make a soft link to the file where it is located. When the program needs a filename as input give it the LASE_LINK name. Platforms tested: SUN (Solaris 2.5 and SunOS 4.1.3) HP (HP-UX 10.10) SGI (IRIX 6.4) Dec Alpha (Digital UNIX V4.0A) Contact: Langley DAAC User and Data Services Office NASA Langley Research Center Mail Stop 157D Hampton, VA 23681-2199 Phone (757)864-8656 Fax (757)864-8807 e-mail: larc@eos.nasa.gov http://eosweb.larc.nasa.gov ********************************************************** Press Return or Enter to continue Please enter the LASE data file name lase_afwex_aer_20001127 Investigator: Browell, Dr. Edward V. Originators: NASA Langley Research Center Source of measurments: LASE / DC-8 Aerosol Scattering Ratio Mission: AFWEX Start date: 11/27/2000 Date processed: 6/21/2000 Independent variables descriptions: ------------------------------------------------------------ GPS altitude of observation (m) Elapsed time in UT seconds from 0 hours on day given by date ------------------------------------------------------------ Special comment lines: -------------------------------------------------------------------- Vertical data interval is 30 m., horizontal data interval is 9 seconds. Vertical resolution is 60 m, horizontal resolution is 9 seconds (2.1 km). These measurements have a maximum estimated error of 5% or 0.1, whichever is larger. The aerosol scattering ratio, the ratio of aerosol to molecular scattering, was determined using molecular density profiles derived from the ARM/CART radiosondes. -------------------------------------------------------------------- ------------------------------------------------------------ This program as delivered will write all the data values to the screen until the end-of-file is reached. The program will display a screen of values and then prompt you for a response. To skip the prompt enter a for yes when prompted. Then if you wish to interrupt the program use CTRL C. (Press the C key while holding down the Ctrl or Control key). Press Return or Enter to continue. ------------------------------------------------------------- 0.001 <--Scale factor by which one multiplies recorded values of the primary variables to convert them to units specified in VNAME(n). VNAME(n) <-- Aerosol Scattering Ratio 84712 <--The Bounded Independent variable. 419 1440 30 <--The first three auxiliary variables are: Number of values for current recorded time GPS altitude at which data begins (m) Altitude increment (m) The Bounded Independent variable: [Has its constant values defined in the file header.] X(i,1), i=1, NX(1) NX = 419 ----------------------------------------------------- auxiliary variables ------------------- GPS altitude of aircraft (m): 11584.00 Hour of day of observation (UT): 23.00 Minute of hour of observation (UT): 31.00 Second of minute of observation (UT): 52.00 Latitude ( +N degrees): 35.00 Longitude ( +E degrees): -112.62 The Unbounded Independent variable: [The index m is always used to count the independent] [variable marks. The implied loop over m is unbounded.] V(i,m,n), i=1,NX n=1,NV NX = 419 NV = 1 ---------------------------------------------------------------------------- 1.6600 1.2350 0.4950 0.9200 0.8480 0.0370 0.2630 0.7400 0.8500 0.5060 -0.0960 -0.5600 -0.3200 0.2420 -0.1470 0.1050 -0.1060 0.3500 0.5990 -0.0650 -0.6480 0.0280 -0.3090 -0.0720 0.2390 0.0670 0.3410 0.1820 -0.2510 -0.4280 -0.1240 -0.0230 -0.3690 0.1460 0.2200 0.3240 -0.3210 -0.0020 0.4000 -0.1970 -0.1670 -0.0600 -0.0120 -0.3650 -0.1630 -0.0920 -0.3950 0.0290 -0.0510 -0.2550 0.0600 -0.2660 -0.1300 -0.1530 -0.1660 0.0060 -0.2160 -0.2550 -0.1230 -0.0210 -0.3430 -0.3220 0.0630 -0.0510 0.4240 0.0760 0.1990 -0.0860 -0.1270 -0.2970 -0.1800 0.2700 0.2420 -0.0330 -0.1650 0.0330 0.0370 -0.1260 -0.1020 -0.2540 -0.4130 -0.2840 -0.1440 -0.0800 -0.1580 -0.2140 -0.0700 -0.1180 -0.2780 0.1470 -0.0400 0.0390 0.3070 -0.0350 -0.0220 0.1440 -0.2320 -0.2940 0.0030 0.1850 0.0580 -0.2450 -0.2110 -0.2970 0.0810 0.3960 0.0230 -0.2720 -0.0380 0.0320 -0.1430 -0.0470 -0.0150 -0.2320 -0.2550 0.0530 0.1640 0.0280 0.1180 -0.2160 -0.0650 0.0190 -0.1110 0.0170 0.1070 0.0530 0.1210 0.1360 0.2290 0.2430 0.0030 0.1770 0.1660 0.0370 -0.1090 -0.0600 -0.0320 -0.1120 -0.1120 -0.0460 0.1430 -0.0250 0.0080 -0.1470 -0.1100 -0.1220 0.0960 -0.0300 0.1830 0.1010 -0.0700 -0.1120 0.0210 -0.0990 -0.0520 0.0880 0.0380 -0.1340 -0.1640 -0.0380 -0.1460 -0.0240 -0.0360 -0.0270 -0.1230 -0.0350 0.0870 -0.0200 -0.0990 0.0920 0.0690 0.1600 0.1100 0.1350 0.1760 0.0740 -0.0320 0.0570 -0.0740 0.0460 0.1100 0.1470 0.0380 0.0000 0.0130 -0.0620 -0.0190 0.0220 -0.0540 -0.1080 0.0050 0.0220 0.0050 -0.0780 0.0800 0.0810 -0.0750 -0.0010 0.1210 -0.0020 -0.0690 -0.0020 0.0000 0.0300 0.1190 0.1670 0.0940 -0.0910 -0.0770 -0.0540 -0.0270 -0.0180 -0.0130 -0.0430 -0.0320 -0.0510 0.0200 0.0180 -0.0840 -0.0060 -0.0880 -0.0050 0.0870 0.0710 0.1520 0.1270 0.0530 0.0710 0.0060 -0.0410 -0.0580 0.1000 0.1220 -0.0220 -0.0710 0.0490 0.0540 0.0560 0.0220 0.0360 0.0230 0.0220 0.0240 0.0440 0.0330 0.0490 0.0490 0.0490 0.0490 0.0490 0.0490 0.0490 0.3850 2.0250 2.6140 3.1040 2.8790 2.0840 1.6980 2.2930 2.3710 1.9080 1.2480 0.9790 0.8320 0.7500 0.7180 0.7480 0.6190 0.5630 0.4910 0.5330 0.7080 0.7250 0.8080 0.8400 0.6930 0.8860 1.0770 1.2440 0.0740 -0.0320 0.0570 -0.0740 0.0460 0.1100 0.1470 0.0380 0.0000 0.0130 -0.0620 -0.0190 0.0220 -0.0540 -0.1080 0.0050 0.0220 0.0050 -0.0780 0.0800 0.0810 -0.0750 -0.0010 0.1210 -0.0020 -0.0690 -0.0020 0.0000 0.0300 0.1190 0.1670 0.0940 -0.0910 -0.0770 -0.0540 -0.0270 -0.0180 -0.0130 -0.0430 -0.0320 -0.0510 0.0200 0.0180 -0.0840 -0.0060 -0.0880 -0.0050 0.0870 0.0710 0.1520 0.1270 0.0530 0.0710 0.0060 -0.0410 -0.0580 0.1000 0.1220 -0.0220 -0.0710 0.0490 0.0540 0.0560 0.0220 0.0360 0.0230 0.0220 0.0240 0.0440 0.0330 0.0490 0.0490 0.0490 0.0490 0.0490 0.0490 0.0490 0.3850 2.0250 2.6140 3.1040 2.8790 2.0840 1.6980 2.2930 2.3710 1.9080 1.2480 0.9790 0.8320 0.7500 0.7180 0.7480 0.6190 0.5630 0.4910 0.5330 0.7080 0.7250 0.8080 0.8400 0.6930 0.8860 1.0770 1.2440 Overscale Overscale 0.0630 0.0830 0.0590 0.0590 0.1040 0.0670 0.0580 0.0960 0.0280 0.0470 0.0460 0.0340 0.0320 Overscale 0.0450 0.0650 0.0480 -0.0140 0.0570 0.0310 0.0460 0.0660 0.0750 0.0020 0.0780 -0.0320 -0.0920 -0.0090 0.0180 -0.0540 -0.0180 -0.0160 End of Data Output of profiles continues until the end-of-file is reached or a CTRL-C is entered (hold down the Control or CTRL key and press the C key). ---------------------------------- Last Modified 10/24/2002