220C97 FIRE_CI2_ER2_LIDAR README THIS IS THE README FILE FOR THE FIRE_CI2_ER2_LIDAR DATA SET. FOR FURTHER INFORMATION PLEASE CONTACT: Langley DAAC Science, User and Data Services Mail Stop 157D 2 South Wright St. NASA Langley Research Center Hampton, VA 23681 email: larc@eos.nasa.gov FAX: (757)864-8807 THE FOLLOWING DESCRIBES THE CLOUD LIDAR CALIBRATED INTERLEAVED DATA FILES ON EXABYTE 8500 TAPES. EACH TAPE HAS ONE OR MORE FILES. EACH FILE CONTAINS CLS DATA FROM AN ENTIRE ER2 SORTIE WHICH TOOK PLACE DURING THE FIRE-1991 PROJECT. THE DATA EXIT ON 8MM TAPE AS ALTERNATING BINARY AND ASCII RECORDS. ALL RECORDS ARE 26680 BYTES LONG. THE FILES HAVE THE FOLLOWING STRUCTURE: A)ONE HEADER RECORD. B)2N RECORDS....AVERAGED CLS CALIBRATED DATA RECORDS ALTERNATING WITH CORRESPONDING ANALYZED VALUES RECORDS. AS OF THE ABOVE DATE, THE ANALYZED VALUES RECORDS CONTAIN THE NUMBER OF CLOUD LAYERS DETECTED,THE HEIGHTS OF THE BOUNDARIES FOR UP TO FIVE CLOUD LAYERS,THE EARTH'S SURFACE DETECTION FLAG, AND THE VERTICAL DEVIATION OF THE EARTH'S SURFACE FROM 0 KM PRESSURE ALTITUDE. EACH PAIR OF RECORDS REPRESENTS 1 SECOND OF LIDAR DATA. SINCE THE CLS OPERATES AT 10HZ, EACH PAIR IS BASED ON 10 CLS SHOTS. THE AVERAGED CLS CALIBRATED DATA REPRESENTS A VERTICAL PROFILE STARTING AT THE ER2 ALTITUDE AND EXTENDING TO THE EARTH'S SURFACE. PRETRIGGER AND BACKGROUND INFORMATION IS CONTAINED AT THEIR RESPECTIVE ENDS OF THE DATA RECORD. C)EOF MARKER. RECORD #1 HEADER RECORD: 26680 BYTES,ASCII FORMAT BYTES 00001-00009:^^^HHMMSS CLS DATA START TIME(UT) BYTES 00010-00017:^^HHMMSS CLS DATA END TIME(UT) BYTES 00018-00025:^^^^^JJJ ER2 SORTIE START JULDAY(UT) BYTES 00026-00033:^^^^^JJJ ER2 SORTIE END JULDAY(UT) BYTES 00034-00041:^^^SSSSS ER2 SORTIE NUMBER BYTES 00041-00046:^^^ ^^^D DETECTOR NUMBER IN CHANNEL 1 POSITION BYTES 00047-00051:^^^^^^^D DETECTOR NUMBER IN CHANNEL 2 POSITION BYTES 00052-00056:^^^^^^^D DETECTOR NUMBER IN CHANNEL 3 POSITION BYTES 00057-00061:^^^^^^^D DETECTOR NUMBER IN CHANNEL 4(LINEAR AMP) DETECTOR 1->532NM PARALLEL DETECTOR 2->532NM PERPENDICULAR DETECTOR 3->1064NM TOTAL SIGNAL BYTES 00062-01024:BLANKS AS OF DATE ABOVE. BYTES 01025-02775:SOME ENGLISH LANGUAGE DESCRIPTIONS OF THE DATA ANALYSIS PARAMETERS AND ER2 INSTRUMENT PACKAGE CONFIGURATION. IF THIS TEXT IS WRITTEN TO 80 BYTE RECORDS, THE TABLE HEADERS WILL ALIGN PROPERLY WITH THE PARAMETER ENTRIES. BYTES 02776-26680:BLANKS END OF HEADER RECORD. THE REST OF THE TAPE CONSISTS OF N PAIRS OF RECORDS. EACH PAIR CONTAINS A CLS AVERAGED,CALIBRATED PROFILE RECORD FOLLOWED BY A CLS ANALYZED DATA RECORD. SINCE THE ASTEX CLS DATA ARE BEING AVERAGED AT 1 SECOND INTERVALS, N IS APPROXIMATELY THE NUMBER OF SECONDS THAT THE CLS OPERATED ON A GIVEN DAY. ALSO, SINCE THE CLS OPERATES AT 10 HZ, EACH RECORD REPRESENTS A 10 CLS SHOT AVERAGE. CLS CALIBRATED SIGNAL RECORD DESCRIPTION:(FIRST RECORD OF EACH PAIR) THE FORTRAN STATEMENTS BELOW PERTAIN TO THE CLOUD LIDAR SYSTEM CALIBRATED AVERAGED SIGNAL PROFILES WHICH CONTAIN HORIZONTALLY AND VERTICALLY AVERAGED CLS PROFILES. THE STRUCTURE OF EACH RECORD IS SHOWN BY THE STATEMENTS DEFINING THE COMMON CLSRECORD_AVE. THE FOLLOWING TABLE LISTS THE IMPORTANT FEATURES OF EACH RECORD. 1. EACH RECORD IS AN TEMPORAL AVERAGE OF 10 CLS SHOTS WHICH IS THE EQUIVALENT OF 1 SECOND OF CLS DATA(CLS OPERATES AT 10HZ). 2. EACH RECORD IS 26680 BYTES LONG. 3. THE FIRST 200 BYTES COMPRISE A HEADER. 4. THE NEXT 6620 BYTES IS THE PROFILE OF CLS CHANNEL l;DURING ASTEX, 532NM PERPENDICULAR. THE PROFILE CONTAINS 1655 SAMPLES. EACH SAMPLE IS A RANGE SQUARED CORRECTED AND SHOT ENERGY NORMALIZED VALUE WHICH IS PROPORTIONAL TO ATTENUATED BACKSCATTER. EACH LIDAR SAMPLE IS STORED AS A 4 BYTE IEEE FLOATING POINT VALUE. THE VERTICAL DISTANCE REPRESENTED BY EACH SAMPLE IS 15 METERS. 5. THE NEXT 6620 BYTES IS THE PROFILE OF CLS CHANNEL 2;DURING ASTEX, 532NM PARALLEL. THE PROFILE CONTAINS 1655 SAMPLES. EACH SAMPLE IS A RANGE SQUARED CORRECTED AND SHOT ENERGY NORMALIZED VALUE WHICH IS PROPORTIONAL TO ATTENUATED BACKSCATTER. EACH LIDAR SAMPLE IS STORED AS A 4 BYTE IEEE FLOATING POINT VALUE. THE VERTICAL DISTANCE REPRESENTED BY EACH SAMPLE IS 15 METERS. 6. THE NEXT 6620 BYTES IS THE PROFILE OF CLS CHANNEL 3;DURING ASTEX, 1064NM TOTAL. THE PROFILE CONTAINS 1655 SAMPLES. EACH SAMPLE IS A RANGE SQUARED CORRECTED AND SHOT ENERGY NORMALIZED VALUE WHICH IS PROPORTIONAL TO ATTENUATED BACKSCATTER. EACH LIDAR SAMPLE IS STORED AS A 4 BYTE IEEE FLOATING POINT VALUE. THE VERTICAL DISTANCE REPRESENTED BY EACH SAMPLE IS 15 METERS. 7. THE NEXT 6620 BYTES IS THE PROFILE OF CLS CHANNEL 4(LINEAR AMP); DURING ASTEX THE DIGITIZED SIGNAL FROM ONE OF THE THREE CLS DETECTORS WAS ROUTED THROUGH A LINEAR AMPLIFIER AND STORED IN THE CHANNEL FOUR POSITION. THE DETECTOR SIGNAL STORED FOR ANY PARTICULAR ER2 FLIGHT IS SPECIFIED IN BYTE 57-61 OF THE FILE HEADER(SEE ABOVE). THE PROFILE CONTAINS 1655 SAMPLES. EACH SAMPLE IS A RANGE SQUARED CORRECTED AND SHOT ENERGY NORMALIZED VALUE WHICH IS PROPORTIONAL TO ATTENUATED BACKSCATTER. EACH LIDAR SAMPLE IS STORED AS A 4 BYTE IEEE FLOATING POINT VALUE. THE VERTICAL DISTANCE REPRESENTED BY EACH SAMPLE IS 15 METERS. 8. EACH CHANNEL PROFILE REPRESENTS: 64 SAMPLES PRECEDING THE LASER TRIGGER PULSE.(PRETRIGGER) DOWNWARD VERTICAL PROFILE FROM ER2,EACH SAMPLE REPRESENTING 15METERS. BELOW THE LEVEL WHERE THE LASER PULSE BECOMES FULLY ATTENUATED, EITHER BY ATMOSPHERIC CONSTITUENTS OR THE EARTH'S SURFACE, EACH SAMPLE REPRESENTS A RANDOM NOISE MEASUREMENT WITHIN THE BACKGROUND SIGNAL BUT DOES NOT CARRY ANY ADDITIONAL PHYSICAL INFORMATION. THE PRETRIGGER AND BACKGROUND SIGNALS OF DETECTORS 1 AND 2(THE 532 NM DETECTORS) REPRESENT ANY DATA SYSTEM ELECTRONIC OFFSET. THE PRETRIGGER AND BACKGROUND SIGNALS OF DETECTOR 3 (1064NM DETECTOR) REPRESENT THE SUM OF ELECTRONIC AND LIDAR RECEIVER RADIATIVE OFFSETS. 9. THE HEADER PARAMETERS ARE: FOUR BYTE WORD LOCATIONS; l)NAVSER=NAVIGATION SERIAL NUMBER (I*4) 2)I_AMPM=AM OR PM INDICATOR (I*4) 3)I_TIMSTAT=TIME STATUS (I*4) 4)JULDAY=JULIAN DATE (I*4) 5)I_HHMMSS=TIME OF DAY (I*4) 6)LAT=LATITUDE IN 1/100 DEGREE (I*4) 7)LON=LONGITUDE IN 1/100 DEGREE (I*4) 8)NS_VEL=NORTH SOUTH SPEED IN 1/10 KNOTS (I*4) 9)EW_VEL=EAST WEST SPEED IN 1/10 KNOTS (I*4) 10)I_TRUE_HEAD=TRUE HEADING IN 1/100 DEGREES (I*4) ll)I_GSPEED=GROUND SPEED IN 1/10 KNOTS (I*4) 12)I_TOTAL_TEMP=TOTAL TEMPERATURE (CELSIUS) (I*4) 13)I_ALT=ER2 ALTITUDE IN FEET. (I*4) 14)I_TRUE_ASPEED=TRUE AIR SPEED IN 1/10 KNOTS (I*4) 15)I_PITCH=ER2 PITCH IN 1/100 DEGREES (I*4) 16)I_ROLL=ER2 ROLL IN 1/100 DEGREES (I*4) 17-31)15 CLS ENGINEERING VALUES (I*4) 32)I_ENERGY_106=1064NM SHOT ENERGY (I*4) 33)I_POD_ROLL=POD ROLL IN 1/100 DEGREES (I*4) 34)I_POD_PITCH=POD PITCH IN 1/100 DEGREES (I*4) 35)I_SHOT_NUM=SHOT NUMBER (I*4) 36)I_ENERGY_532=532NUM ENERGY (I*4) 37)I_FLAGS=CLS OPERATIONS FLAGS (I*4) 38)I_SPARE=SPARE LOCATION(NOT USED) (I*4) 39-42)INVALID_SHOT_AVE=ONE VALUE FOR EACH (I*4) CHANNEL;INDICATORS OF INVALID SAMPLES USED SOMEWHERE IN SHOT AVERAGES. 0=ALL SAMPLES USED IN AVERAGE ARE VALID AND UNAMBIGUOUS. l=AT LEAST ONE VALUE IS AMBIGUOUS ON THE LOW SIDE(THAT IS = 0) 2=AT LEAST ONE VALUE IS AMBIGUOUS ON THE HIGH SIDE(THAT IS = 255) 3=AT LEAST ONE LOW AND AT LEAST ONE HIGH AMBIGUOUS SAMPLES USED IN AVERAGE. 43-46)PRETRIGS=AVERAGED PRETRIGGER SIGNALS; (REAL*4) ONE FOR EACH CLS CHANNEL. 47-50)BACKGROUNDS=AVERAGED BACKGROUND SIGNALS; (REAL*4) ONE FOR EACH CLS CHANNEL. 50 FOUR BYTE WORDS = 200 BYTE HEADER PORTION. 6620 X 4 BYTES OF AVERAGED CLS CALIBRATED BACKSCATTER. 200+26480=26680 BYTES/RECORD **************************************************************************** LOGICAL*l CLS_RECORD_AVE(26680)!3lAU93 LOGICAL*4 INVALID_SHOT_AVE(4) INTEGER*4 I_SHOT_HEAD_DECODE(38),I_ENGINEERING(15) REAL PRETRIGS(4),BACKGROUNDS(4) !IEEE FLOATING POINT FORMAT REAL CLS_AVE_FLOAT(1655,4) !IEEE FLOATING POINT FORMAT COMMON /CLSRECORD_AVE/NAVSER,I_AMPM,I_TIMSTAT,JULDAY,I_HHMMSS, + LAT,LON,NS_VEL,I_EW_VEL,I_TRUE_HEAD, + I_GSPEED,I_TOTAL_TEMP,I_ALT,I_TRUE_ASPEED, + I_PITCH,I_ROLL,I_ENGINEERING,I_ENERGY_106, + I_POD_ROLL,I_POD_PITCH,I_SHOT_NUM, + I_ENERGY_532,I_FLAGS,I_SPARE, + INVALID_SHOT_AVE,PRETRIGS,BACKGROUNDS, + CLS_AVE_FLOAT EQUIVALENCE(CLS_RECORD_AVE(l),NAVSER) END OF CLS CALIBRATED SIGNAL RECORD DESCRIPTION. DESCRIPTION OF CLS ANALYZED DATA RECORD(SECOND RECORD OF EACH PAIR) EACH OF THESE RECORDS IS 26680 BYTES OF ASCII. THE FIRST 137 BYTES CONTAIN ANALYZED INFORMATION AND THE REST ARE ASCII BLANKS RESERVED FOR FUTURE USE. THE FIELDS ARE DEFINED AS FOLLOWS: BYTES 00001-00008 HH.HHHH time in hours, UT from ER2 INS BYTES 00009-00016 +/-aa.aa decimal latitude; to 1/100 degree;INS BYTES 00017-00024 +/-nnn.nn decimal longitude;l/100 degress;INS BYTES 00025-00031 hh.hh ER2 pressure altitude;l/100 kms. INS BYTES 00032-00038 +/-rr.rr ER2 aircraft roll; 1/100 degrees. INS BYTES 00039-00040 nn Number of cloud layers detected;<=5~, BYTES 00041-00042 g Ground detection flag;l=TRUE;0=FALSE BYTES 00043-00056 tt.ttt bb.bbb top and bottom of detected layer 1 based upon pressure altitude -3.000 denotes no cloud layer detected BYTES 00057-00070 tt.ttt bb.bbb top and bottom of detected layer 2 BYTES 00071-00077 hhmmss occasional annotation of time,hhmmss BYTES 00078-00085 HH.HHHH time in hours;matches time in bytes 1-8 BYTES 00086-00100 tt.ttt bb.bbb top and bottom of detected layer 3 BYTES 00101-00114 tt.ttt bb.bbb top and bottom of detected layer 4 BYTES 00115-00128 tt.ttt bb.bbb top and bottom of detected layer 5 BYTES 00129-00137 gg.ggg departure of height of earth's surface from 0;-9.900 means no surface signal detected. This should be consistent with ground detection flag in the part 1 file. By subtracting this value from the cloud boundary height values, they can be adjusted to the geometrical distance above the earth's surface, if the aircraft was above the ocean. BYTES 00138-26680 ASCII BLANKS END DESCRIPTION OF CLS ANALYZED DATA RECORD(SECOND RECORD OF EACH PAIR) THE FILE ENDS WITH ONE EOF. LATITUDE AND LONGITUDE RANGES: THE RANGES FOR THE LATITUDE AND LONGITUDE VALUES ARE GIVEN WITHIN THE FILE HEADER. DATA WAS COLLECTED DURING BOTH DAY AND NIGHT (MOSTLY WHEN THE SUN WAS ABOVE THE HORIZON). BROWSE FILES: THERE IS ONE BROWSE FILE FOR EACH DATA FILE. THE BROWSE FILES ARE IN HDF FORMAT. SIZE OF EACH IMAGE (IN BYTES):200-400kb RESOLUTION OF EACH IMAGE:1100x840 THE GIF AND ASCII FILES ARE AVAILABLE AT : URL http://virl.gsfc.nasa.gov/fire91.html SOFTWARE: A 'C' PROGRAM, 'read_lidar.c', HAS BEEN PROVIDED TO READ THE DATA FILES. THE PROGRAM MAY BE COMPILED USING THE COMMAND cc -o read_lidar read_lidar.c This generates the executable 'read_lidar'. The program can now be invoked by typing 'read_lidar' at the command line. When the program executes, a menu will be displayed from which the user may select various options. DATA SET POINT OF CONTACT: NAME: BILL HART ADDRESS: CODE 912 NASA/GSFC GREENBELT,MD 20771 TELEPHONE: 301-286-4936 FAX: 301-286-1762 INTERNET ADDRESS: billhart@virl.gsfc.nasa.gov URL: http://virl.gsfc.nasa.gov/fire91.html