CCSD1Z00000100000052CCSD1R00000300000032 DELIMITER=EOF; TYPE=CCSD1F000001; CCSD1C00000400000039 ADI=NURSPE45; SUD=NURSUC03; SUD=NURSPE00; CCSD1R00000300000032 DELIMITER=EOF; TYPE=CCSD1D000002; PEM X-RAY LEVEL 3AT DATA DESCRIPTION IN SFDU FORMAT Whole Data Set ============== DataSetName: PEM_Xray_Level_3AT_description DataSource: UARS/PEM UARS = Upper Atmosphere Research Satellite PEM = Particle Environment Monitor ScientificContact: Dr. David Chenette O/91-20 B/255 Lockheed R&D Division 3251 Hanover Street Palo Alto, CA, 94304-1191, USA e-mail: chenette@pemaxs.space.lockheed.com PEMAXS::CHENETTE (UARSNET) LOCKHD::CHENETTE (SPAN) FAX: 415-424-3449 phone: 415-424-3333 SourceCharacteristics: Refer to NURSPE00 InvestigationObjectives: Refer to NURSPE00 InstrumentAttributes: Refer to NURSPE00 MeasuredParameters: Refer to NURSPE00 DataSetQuality: Data quality is presented at level 0 by the Data Capture Facility and reflects the confidence level of the telemetry. These quality values are preserved and along with PEM instrument checks, the quality values are used to generate level 2 quality information. Level 2 read routines apply instrument corrections which may modify the quality fields stored in level 2 and these results are presented along with the data to level 3AT processing. Confidence limits in the form of standard deviations for each data point are set using count rate statistics, the data compression error associated with each readout, and the range of expected values (based on similar previous satellite measurements). All input data are examined in the level 3AT processing. PEM is an energy input instrument and the Level 3AT x-ray data products are altitude profiles of energy deposition rate determined for precipitating electrons as inferred from the atmospheric x-ray bremsstrahlung spectrum (AXIS). In addition to the quality indicators per data point, there is a quality indicator per file stored in the CDHF database. The UARS Science Team discussed the data quality indicators, n.q, which are applied to daily data files in the CDHF, and the following was decided: The n's are defined as: n = 0: machine inspected data, n = 1: qualitative evaluation, n = 2: intensive analysis; The q's are defined as: q = 1: the data in the file are < 50% good; q = 2; the data in the file are 50% to 75% good; q = 3; the data in the file are 76% to 98% good; q = 4; the data in the file are > 98% good; For the PEM X-ray Level 3AT file, the production process assigns a value of n = 0 to indicate machine inspected data, and q is determined by the percentage of time when the instrument is observing in its normal mode with adequate data quality. These requirements may not be met for the following reasons: (1) fill data due to spacecraft, communications, and telemetry processing, (2) instrument off, in calibration mode, or not set to normal operating mode, (3) uncorrectable levels of background or other types of data contamination, (4) uncorrectable instrument responsivity or performance changes. The items under (3) and (4) may be addressed in future versions of the software. DataProcessingOverview: Sixteen PEM X-ray Level 3AT files are generated by the production program PEMAXIS_DEP, one for each AXIS pixel. PEMAXIS_DEP uses the PEM Level 2 data for input. The Level 2 read routines are accessed which return data to the Level 3AT process as x-ray pulse height distributions in counts per channel. These are fitted to pre-computed models to extract the energy flux and mean energy of the precipitating electrons. Altitude profiles of energy deposition due to these electrons are scaled using these parameters from profiles that were pre-computed for a wide range of mean energies. Energy deposition profiles are mapped to the correct location based on the position of the spacecraft and the AXIS field of view directions. These values are then written to the PEM x-ray Level 3AT file. (See the Algorithms section for details.) DataUsage: Data included in this file are altitude profiles of the energy deposited by precipitating electrons in each of the 16 AXIS fields of view. These results are reported every UARS minute. The use of these data is unrestricted, however there are some assumptions which may affect the interpretation of the results. The first is that the precipitating electron source model is a pure exponential in electron kinetic energy. The second is that the electron directional distribution at the top of the atmosphere is isotropic in the downward hemisphere. In addition, it is important to note that AXIS is insensitive to the effects of electrons with energies below 3 keV and has reduced sensitivity to the effects of electrons above 200 keV. Thus at the highest and lowest altitudes, where electrons with these energies are most important, the reported results should be used with discretion. Another important assumption is that the atmosphere may be described by the 1976 US Standard Atmosphere (see reference below). The US Standard Atmospheric Mass Density (g/cm**3) may be used to include the dependence of the atmospheric model using the following table: Atmospheric UARS Mass Density Altitude index (g/cm**3) 88 2905950E-21 87 3168611E-21 86 3457383E-21 85 3775162E-21 84 4125200E-21 83 4511124E-21 82 4937086E-21 81 5407737E-21 80 5928330E-21 79 6504878E-21 78 7144004E-21 77 7853276E-21 76 8641270E-21 75 9516793E-21 74 1049204E-20 73 1158012E-20 72 1279610E-20 71 1415803E-20 70 1568508E-20 69 1739997E-20 68 1932890E-20 67 2150058E-20 66 2395480E-20 65 2673666E-20 64 2989550E-20 63 3349080E-20 62 3758930E-20 61 4226352E-20 60 4762440E-20 59 5380936E-20 58 6095200E-20 57 6921054E-20 56 7880750E-20 55 9000697E-20 54 1031370E-19 53 1186013E-19 52 1369090E-19 51 1586900E-19 50 1847640E-19 49 2161526E-19 48 2542360E-19 47 3007750E-19 46 3581700E-19 45 4295290E-19 44 5193400E-19 43 6335951E-19 42 7811800E-19 41 9743304E-19 40 1232390E-18 39 1583035E-18 38 2073680E-18 37 2775982E-18 36 3826590E-18 35 5446421E-18 34 8138960E-18 33 1284476E-17 32 2217720E-17 31 3312867E-17 30 5136439E-17 29 8222952E-17 28 1353687E-16 27 2277124E-16 26 3888122E-16 25 6697204E-16 24 1156788E-15 23 1990062E-15 22 3401950E-15 21 5791054E-15 20 9661521E-15 19 1569099E-14 18 2513226E-14 17 3973350E-14 16 6191171E-14 15 9475890E-14 14 1423159E-13 13 2107805E-13 12 3082460E-13 11 5653650E-13 10 1022060E-12 9 1956184E-12 8 3977180E-12 7 8424940E-12 6 1832530E-11 5 3989630E-11 4 8851480E-11 3 1938330E-10 2 4116010E-10 1 7329160E-10 "U.S. Standard Atmosphere, 1976", Compiled by the National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration, and the United States Air Force, Washington, DC, (U.S. Government Printing Office) October 1976. The Average Energy for Each Ionization may be taken as 35 [eV/ionization]. >From this total ionization rate below 100 km, fractions may indicate the ionization rate for several ions. This fraction is listed below: Ionizations of N2+ [fraction of ionization rate] = 0.585 Ionizations of N+ [fraction of ionization rate] = 0.185 Ionizations of O2+ [fraction of ionization rate] = 0.154 Ionizations of O+ [fraction of ionization rate] = 0.076 DataOrganization: FileClassRelationships: LitReferences: "Particle Environment Monitor Software Specifications, Data Descriptions, and Algorithms," Southwest Research Institute Document 7845-SDD, San Antonio, Texas. Referred to as the SDD document. Winningham, J.D., J.R. Sharber, R.A. Frahm, J.L. Burch, N. Eaker, R.K. Black, V.A. Blevins, J.P. Andrews, J. Rudzki, M.J. Sablik, D.L. Chenette, D.W. Datlowe, E.E. Gaines, W.I. Imhof, R.W. Nightingale, J.B. Reagan, R.M. Robinson, T.L. Schumaker, E.G. Shelley, R.R.Vondrak, H.D. Voss, P.F. Bythrow, B.J. Anderson, T.A. Potemra, L.J. Zanetti, D.B. Holland, M.H. Rees, D. Lummerzheim, G.C. Reid, R.G. Roble, C.R. Clauer, and P.M. Banks, "The UARS Particle Environment Monitor", J. Geophys. Res., 98, 10649-10666, 1993. File Class ========== FileClassName: PEM_XRAY_LEVEL3AT RecordTypeNames: SFDU_Label, File_Label_Record, Continuation_Label_Record, Data_Record Algorithms: What is stored in the level 3AT x-ray file: ---------------------------------------------- The energy deposition and corresponding standard deviation are reported for each UARS altitude at the center of a UARS minute. The units for each reported value are keV/(g-s). UARS standard altitudes may be determined by the following: dimension z(88) c determine the defined UARS altitude levels do i=1,88 if (i .le. 12) then z(i) = float(5*i) else if (i .le. 32) then z(i) = float(60+3*(i-12)) else z(i) = float(120+5*(i-32)) endif enddo Inputs to the level 3AT x-ray file: -------------------------------------- Inputs to the level 3AT algorithm are the data and quality information which are included in the level 2 AXIS and AXIS engineering files. Level 0 engineering files and spacecraft O/A services are also accessed. Definitions of terms and symbols: Ex - x-ray energy Ee - electron kinetic energy Eo - mean energy of electron flux distribution (assumed exponential) a - x-ray emission angle from vertical. This is matched to a specific pixel z - altitude or depth in the atmosphere X(Ex,Eo,a) - x-ray flux per incident electron from source model calculation Q(z,Eo) - altitude (z) profile of atmospheric energy deposition per incident electron from source model calculation Ed(z) - altitude profile of atmospheric energy deposition scaled by best fit intensity and selected by best fit Eo eG(Ex) - combined efficiency-geometry factor, may be pixel dependent s - energy resolution parameter for x-ray detection, may be pixel dependent e(i,Eo,t) = ei(Eo) - calculated pulse-height analysis (PHA) distribution for channel i, model Eo Ni - the measured pulse-height analysis (PHA) distribution count for channel i ni - the estimated uncertainty of the measurement of channel i (above) Si - the soft background component for channel i (its uncertainty is si) Di - the linear channel width corresponding to output channel i Aj - the defined amplitude fit parameter. The j labels the Eo model used. Bj - the hard background fit parameter. The j labels the Eo model used. PART 1: One-time calculations Step 1: An electron-photon transport code was run which took a distribution of electrons as an exponential in kinetic energy, isotropic in the downward hemisphere, homogeneous in time and space over the top of a plane-parallel atmosphere, and returned both the altitude profile of energy deposition, Q(z,Eo), and the x-ray flux escaping from the top of the atmosphere, X(Ex,Eo,a), for a selection of mean energy (Eo) values ranging from 1 keV to 100 keV in 20% steps. These results were normalized per unit incident electron, i.e. the calculated x-ray spectrum flux intensity as a function of x-ray energy and angle and the energy deposition profile as a function of altitude were divided by the total number of electrons used in the calculation. The processing of AXIS data on the CDHF is directed to using the measured x-ray spectra to determine a best-fit values of Eo and an overall intensity scale factor. The energy deposition profile reported as the level 3AT result is selected by the best-fit Eo and scaled by the best fit intensity. Step 2: The x-ray flux source models from the above calculations were used to calculate expected instrument response distributions for each AXIS pixel. This calculation was in two parts. First, the x-ray spectrum was multiplied by the detector efficiency function and convolved with a unit-normalized Gaussian. The width of this Gaussian was chosen to represent accurately the measured energy resolution of each AXIS detector and electronics subsystem. Second, this spread x-ray spectrum was used with a model of the geometric response function to calculate the number of counts expected in each channel for each spectrum for each pixel. The resulting pulse-height analysis (PHA) distributions were scaled by two constants [for a general discussion of the pulse-height analysis technique, see section 6.4.5 from Moore, J. H., C. C. Davis, and M. A. Coplan, Building Scientific Apparatus (Addison-Wesley:London) 1983]. These constants are, first, an intensity scaling parameter (denoted Ao), and second, a time scaling parameter (denoted t, which was numerically equal to 8.192 seconds). Thus the PHA distributions could be interpreted as the number of counts expected in channel i for an exponential electron spectrum with mean energy Eo and a total number of incident electrons Ao per unit area at the top of the atmosphere, for a period corresponding to an AXIS instrument livetime of 8.192 seconds. PART 2: Analysis performed on an arbitrary data accumulation All of the work in steps 1 and 2 was done in advance of the analysis for any specific data period. The material that follows describes how these results are applied to a sample of AXIS data. The data used in this analysis are the 32-channel pulse-height analysis (PHA) distributions for each AXIS detector. These data are available in the telemetry every 8.192 seconds in 8.192 second accumulations. Longer integration periods are obtained by summing these distributions. For the CDHF analysis they are summed into 65.536 second intervals defined by the observation time corresponding to each UARS EMAF. In version 4 of the AXIS analysis procedure we choose to model the measured PHA distribution in the following way. The index i labels a PHA channel, j labels an Eo model: Ni is modeled as = Aj ei + Bj Di + Si Si is the soft background for channel i. This component typically is accumulated during the period surrounding the measurement of interest. It is not adjustable and is not a parameter. It includes the galactic cosmic ray and electronic noise quiet-time background components. Aj and Bj are adjustable parameters used to match the model to the data. Aj is the amplitude of the real x-ray source component and Bj is the amplitude of a background component. The selection of this form has several motivations and rationalizations, some of which are discussed below. In particular, the variable spiky background due to intense fluxes of electrons and other high energy particles on the instrument often appears to be constant per unit of deposited energy. Thus it scales as the number of linear input channels per output channel (Di). The uncertainty in Ni includes the channel compression table effect and counting statistics. The pulse height distribution Ni is accumulated and used for each pixel separately including all good observations accumulated during each UARS EMAF. Given this model, the parameters Aj and Bj are extracted for each Eo by a minimizing the sum of squares of the difference between the model and data. Each term is normalized by the combined estimated variance of the data and background, and the result is interpreted as a chi-square function following the usual statistical conventions. The Aj and Bj parameters are calculated for each Eo by equating the derivative of this chi-square function with respect to each of these parameters to zero. Using this procedure best fit values and uncertainties are obtained for the A and B parameters for any model spectrum (characterized by the value of Eo, the mean energy of the precipitating electrons). Thus three functions of Eo are accumulated: the chi-square C2j = C2(Eoj), the intensity parameter Aj = A(Eoj), and the background parameter Bj = B(Eoj). The best-fit Eo is determined by fitting the five smallest values of the chi-squared function to a quadratic in Eo and solving for the minimum (Eo*). The best-fit values of A and B, A* = A(Eo*) and B* = B(Eo*), are then calculated by interpolating the tabulated functions. The 3x3 Hessian matrix (second derivatives of the chi-square function with respect to each of the parameters A, B, and Eo) is inverted to obtain estimates for the variances of the parameters according to the standard statistical treatment. The second derivatives with respect to A, B, and their cross term are obtained using analytic expressions. Derivatives involving Eo are computed numerically. Part 3: Reconstructing the energy deposition profile Remembering that the original x-ray flux models were normalized per unit input electron, Ne, the number of incident electrons is proportional to A*. If we denote the constant of proportionality as K, then the altitude profile of electron energy deposition (Ed) determined for a specific AXIS detector is Ed(z) = A* K Q(z,Eo*). The variance of Ed is computed from the variances of A* and Eo* according to the usual statistical conventions, including the correlations among the parameters. Part 4: Determining the location of the result The latitude and longitude reported in the level 3AT file, expressed in geodetic coordinates, represent the location where the center of the field of view of each AXIS pixel intersects a surface at 100-km altitude at a time corresponding to the center time of the averaging interval. This depends on the location and attitude of the UARS spacecraft and a fixed set of look direction unit vectors for AXIS, which are expressed in UARS coordinates. The position and attitude of UARS are provided by O/A services. FileClassSyntax: Number of records is specified in the File_Label_Record List of Records in file: #1: SFDU_Label #2: File_Label_Record #3: Continuation_Label_Record Zero or more as specified in the File_Label_Record #4: Data_Record One or more as specified in the File_Label_Record Record ====== 1. SFDU_Label ------------- RecordName: SFDU_Label RecordStructure: Fixed Length RecordLength: 40 Bytes RecordFieldNames: Tz_Field, Lz_Field, Ti_Field, Li_Field RecordSyntax: 4 Fields #1: Tz_Field #2: Lz_Field #3: Ti_Field #4: Li_Field Fields ====== 1.1 Tz_Field ------------ FieldName: Tz_Field FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: SFDU Type (Tz) Field. Constant Value = 'CCSD1Z000001'. FieldRepresentation: 12A FieldDisplayFormat: A12 1.2 Lz_Field ------------ FieldName: Lz_Field FieldSyntax: ASCII Character*8 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: SFDU Length (Lz) Field. 20 + l where l is the length of the UARS file. Right justified, zero filled FieldRepresentation: 8A FieldDisplayFormat: A8 1.3 Ti_Field ------------ FieldName: Ti_Field FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: SFDU Type (Ti) Field. Constant value = 'NURS1I00PE45' FieldRepresentation: 12A FieldDisplayFormat: A12 1.4 Li_Field ------------ FieldName: Li_Field FieldSyntax: ASCII Character*8 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: SFDU Length (Lz) Field. Length of UARS file. Right justified, zero filled FieldRepresentation: 8A FieldDisplayFormat: A8 Record ====== 2. File_Label_Record -------------------- RecordName: File_Label_Record RecordStructure: Variable Length RecordLength: Max (148 + 28 * n, length of Data_Record) where n = Value (Number_of_Time/Version_Entries_in_Record) RecordFieldNames: Satellite_Identifier Record_Type Instrument_Identifier Data_Subtype_Or_Species Format_Version_Number Physical_Record_Count Number_Of_Continuation_Records_For_File_Label Number_Of_Physical_Records_In_File File_Creation_Time_In_VAX_VMS_ASCII_Format Year_For_First_Data_Record Day_Of_Year_For_First_Data_Record Milliseconds_Of_Day_For_First_Data_Record Year_For_Last_Data_Record Day_Of_Year_For_Last_Data_Record Milliseconds_Of_Day_For_Last_Data_Record Data_Level UARS_Day_Number Number_Of_Data_Points_Per_Record Base_Index_Of_Data_Point_Values Record_Length_In_Bytes CCB_Version_Number File_Cycle_Number Virtual_File_Flag Total_Number_Of_Time/Version_Entries_In_File Number_Of_Time/Version_Entries_In_Record Version_Entries RecordSyntax: 26 Fields #1 : Satellite_Identifier #2 : Record_Type #3 : Instrument_Identifier #4 : Data_Subtype_Or_Species #5 : Format_Version_Number #6 : Physical_Record_Count #7 : Number_Of_Continuation_Records_For_File_Label #8 : Number_Of_Physical_Records_In_File #9 : File_Creation_Time_In_VAX_VMS_ASCII_Format #10: Year_For_First_Data_Record #11: Day_Of_Year_For_First_Data_Record #12: Milliseconds_Of_Day_For_First_Data_Record #13: Year_For_Last_Data_Record #14: Day_Of_Year_For_Last_Data_Record #15: Milliseconds_Of_Day_For_Last_Data_Record #16: Data_Level #17: UARS_Day_Number #18: Number_Of_Data_Points_Per_Record #19: Base_Index_Of_Data_Point_Values #20: Record_Length_In_Bytes #21: CCB_Version_Number #22: File_Cycle_Number #23: Virtual_File_Flag #24: Total_Number_Of_Time/Version_Entries_In_File #25: Number_Of_Time/Version_Entries_In_Record #26: Version_Entries Fields ====== 2.1 Satellite_Identifier ------------------------ FieldName: Satellite_Identifier FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Satellite identifier. Constant value 'UARS' FieldRepresentation: 4A FieldDisplayFormat: A4 2.2 Record_Type --------------- FieldName: Record_Type FieldSyntax: ASCII Character*2 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Record type. Constant value ' 1' indicates a file label record. FieldRepresentation: 2A FieldDisplayFormat: A2 2.3 Instrument_Identifier ------------------------- FieldName: Instrument_Identifier FieldMnemonic: Data_Type FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Instrument identifier. Constant value = 'PEM ' FieldRepresentation: 12A FieldDisplayFormat: A12 2.4 Data_Subtype_Or_Species --------------------------- FieldName: Data_Subtype_Or_Species FieldMnemonic: Subtype FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Data subtype or species. Left justified, blank filled. The sixteen subtypes/species for PEMAXIS are: Constant value = 'EDEP3AT_P01' (for AXIS Pixel 1 file) Constant value = 'EDEP3AT_P02' (for AXIS Pixel 2 file) Constant value = 'EDEP3AT_P03' (for AXIS Pixel 3 file) Constant value = 'EDEP3AT_P04' (for AXIS Pixel 4 file) Constant value = 'EDEP3AT_P05' (for AXIS Pixel 5 file) Constant value = 'EDEP3AT_P06' (for AXIS Pixel 6 file) Constant value = 'EDEP3AT_P07' (for AXIS Pixel 7 file) Constant value = 'EDEP3AT_P08' (for AXIS Pixel 8 file) Constant value = 'EDEP3AT_P09' (for AXIS Pixel 9 file) Constant value = 'EDEP3AT_P10' (for AXIS Pixel 10 file) Constant value = 'EDEP3AT_P11' (for AXIS Pixel 11 file) Constant value = 'EDEP3AT_P12' (for AXIS Pixel 12 file) Constant value = 'EDEP3AT_P13' (for AXIS Pixel 13 file) Constant value = 'EDEP3AT_P14' (for AXIS Pixel 14 file) Constant value = 'EDEP3AT_P15' (for AXIS Pixel 15 file) Constant value = 'EDEP3AT_P16' (for AXIS Pixel 16 file) FieldRepresentation: 12A FieldDisplayFormat: A12 2.5 Format_Version_Number ------------------------- FieldName: Format_Version_Number FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Format version number. Constant value ' 1' indicates that this is the first version of the Level 3AT file structure. FieldRepresentation: 4A FieldDisplayFormat: A4 2.6 Physical_Record_Count ------------------------- FieldName: Physical_Record_Count FieldSyntax: ASCII character*8 string FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Physical record count. Constant value ' 1' indicates the label record is the logical first record in the file. FieldRepresentation: 8A FieldDisplayFormat: A8 2.7 Number_Of_Continuation_Records_For_File_Label ------------------------------------------------- FieldName: Number_Of_Continuation_Records_For_File_Label FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 0 FieldDescription: Number of continuation records for file label for a virtual file (a level 3AT file containing a user specified time range that is not on day boundaries). Right justified, blank filled FieldRepresentation: 4A FieldDisplayFormat: A4 2.8 Number_Of_Physical_Records_In_File -------------------------------------- FieldName: Number_Of_Physical_Records_In_File FieldSyntax: ASCII Character*8 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Number of physical records in file. Right justified, blank filled. Does not count SFDU label record. FieldRepresentation: 8A FieldDisplayFormat: A8 2.9 File_Creation_Time_In_VAX_VMS_ASCII_Format ---------------------------------------------- FieldName: File_Creation_Time_In_VAX_VMS_ASCII_Format FieldSyntax: ASCII Character*23 String FieldUnits: dd-mmm-yyyy hh:mm:ss.cc FieldResolution: 0.01 second FieldRange: n/a FieldDescription: File creation time in VAX VMS ASCII format indicates the date and time the file was cataloged in the UCSS. FieldRepresentation: 23A FieldDisplayFormat: A23 2.10 Year_For_First_Data_Record ------------------------------- FieldName: Year_For_First_Data_Record FieldSyntax: ASCII Character*3 String FieldUnits: Years since 1900 FieldResolution: n/a FieldRange: n/a FieldDescription: Year for first data record. Value is Year-1900. Right justified, blank filled. FieldRepresentation: 3A FieldDisplayFormat: A3 2.11 Day_Of_Year_For_First_Data_Record -------------------------------------- FieldName: Day_Of_Year_For_First_Data_Record FieldSyntax: ASCII Character*3 String FieldUnits: Day of Year FieldResolution: n/a FieldRange: Integer >= 1, <= 366 FieldDescription: Day of year for first data record. Right justified, blank filled. FieldRepresentation: 3A FieldDisplayFormat: A3 2.12 Milliseconds_Of_Day_For_First_Data_Record ---------------------------------------------- FieldName: Milliseconds_Of_Day_For_First_Data_Record FieldSyntax: ASCII Character*8 String FieldUnits: Milliseconds FieldResolution: 1 millisecond FieldRange: Integer >=0, <= 86399999 FieldDescription: Milliseconds of day for first data record. Right justified, blank filled. FieldRepresentation: 8A FieldDisplayFormat: A8 2.13 Year_For_Last_Data_Record ------------------------------ FieldName: Year_For_Last_Data_Record FieldSyntax: ASCII Character*3 String FieldUnits: Years since 1900 FieldResolution: n/a FieldRange: n/a FieldDescription: Year for last data record. Value is Year-1900. Right justified, blank filled. FieldRepresentation: 3A FieldDisplayFormat: A3 2.14 Day_Of_Year_For_Last_Data_Record ------------------------------------- FieldName: Day_Of_Year_For_Last_Data_Record FieldSyntax: ASCII Character*3 String FieldUnits: Day of year FieldResolution: n/a FieldRange: Integer >= 1, <= 366 FieldDescription: Day of year for last data record. Right justified, blank filled. FieldRepresentation: 3A FieldDisplayFormat: A3 2.15 Milliseconds_Of_Day_For_Last_Data_Record --------------------------------------------- FieldName: Milliseconds_Of_Day_For_Last_Data_Record FieldSyntax: ASCII Character*8 String FieldUnits: Milliseconds FieldResolution: 1 millisecond FieldRange: Integer >= 0, <= 86399999 FieldDescription: Milliseconds of day for last data record. Right justified, blank filled. FieldRepresentation: 8A FieldDisplayFormat: A8 2.16 Data_Level --------------- FieldName: Data_Level FieldSyntax: ASCII Character*3 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Data level. Constant value '3AT' indicates data that has been placed on the standard UARS time and pressure grid. FieldRepresentation: 3A FieldDisplayFormat: A3 2.17 UARS_Day_Number -------------------- FieldName: UARS_Day_Number FieldMnemonic: UARS_Day FieldSyntax: ASCII Character*4 String FieldUnits: Days FieldResolution: 1 day FieldRange: Integer >= 1 FieldDescription: UARS day number (UARS day 1 = September 12, 1991) Right justified, blank filled. FieldRepresentation: 4A FieldDisplayFormat: A4 2.18 Number_Of_Data_Points_Per_Record ------------------------------------- FieldName: Number_Of_Data_Points_Per_Record FieldMnemonic: Max_Points FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: Constant integer value = 88 FieldDescription: Number of data points per record. Right justified, blank filled. FieldRepresentation: 4A FieldDisplayFormat: A4 2.19 Base_Index_Of_Data_Point_Values ------------------------------------ FieldName: Base_Index_Of_Data_Point_Values FieldMnemonic: Base_Index FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: Constant integer value = 1 FieldDescription: Base_Index is the starting (lowest) grid index for the standard UARS grid present in the data array of the file (i.e. the data entry in the first element in the DATA3A array is the data value for the UARS standard grid at the position indicated by the value of Base_ Index). The base_index, together with the Max_Points, determine the dimensions of the Level 3 array. The UARS Standard grids are defined in Appendix E of the UCSS Programmer's Guide. Right justified, blank filled. FieldRepresentation: 4A FieldDisplayFormat: A4 2.20 Record_Length_In_Bytes --------------------------- FieldName: Record_Length_In_Bytes FieldSyntax: ASCII Character*5 String FieldUnits: Bytes FieldResolution: 4 bytes FieldRange: Constant integer value = 768 FieldDescription: Record length in bytes. Right justified, blank filled. Value is 4*Integerpart ((Max(148, 64 + 8*n) + 3)/4) where n = Value (Number_Of_Data_Points_per_Record) FieldRepresentation: 5A FieldDisplayFormat: A5 2.21 CCB_Version_Number ----------------------- FieldName: CCB_Version_Number FieldSyntax: ASCII Character*9 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >=1, <= 9999 FieldDescription: Version number assigned by the UCSS Configuration Control Board in conjunction with the Principal Investigator to differentiate versions of data. Right justified, blank filled FieldRepresentation: 9A FieldDisplayFormat: A9 2.22 File_Cycle_Number ---------------------- FieldName: File_Cycle_Number FieldSyntax: ASCII Character*5 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >=1, <= 31 FieldDescription: File cycle number right justified, blank filled Supplied only during file creation by a Remote Access Computer data transfer, otherwise undefined. The cycle number is incremented if necessary to provide a unique catalog entry at the UARS CDHF. FieldRepresentation: 5A FieldDisplayFormat: A5 2.23 Virtual_File_Flag ---------------------- FieldName: Virtual_File_Flag FieldSyntax: ASCII Character*1 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: The Virtual_File_Flag is set to ' ' if a file is a production file containing all the available data for one specific day or 'V' if the file is created by a Remote Access Computer data transfer where a user specified time range is not on day boundaries. FieldRepresentation: 1A FieldDisplayFormat: A1 2.24 Total_Number_Of_Time/Version_Entries_In_File ------------------------------------------------- FieldName: Total_Number_Of_Time/Version_Entries_In_File FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 0 FieldDescription: Total number of time/version entries in file. Only used for for virtual files created via RAC data transfer. Right justified, blank filled. FieldRepresentation: 4A FieldDisplayFormat: A4 2.25 Number_Of_Time/Version_Entries_In_Record --------------------------------------------- FieldName: Number_Of_Time/Version_Entries_In_Record FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 0 FieldDescription: Number of time/version entries in record. Right justified, blank filled. FieldRepresentation: 4A FieldDisplayFormat: A4 2.26 Version_Entries -------------------- FieldName: Version_Entries FieldSyntax: ASCII Character*28 String 1-D Array (n), where n is value (Number_Of_Time/Version_Entries_In_Record) FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: List of version entries. Each version entry contains: Version_Entries (1:3) start year Version_Entries (4:6) start day of year Version_Entries (7:14) start milliseconds of day Version_Entries (15:24) version number Version_Entries (24:28) cycle number FieldRepresentation: n(28A) FieldDisplayFormat: nA28 Record ====== 3. Continuation_Label_Record ---------------------------- RecordName: Continuation_Label_Record RecordStructure: Variable Length RecordLength: Max (48 + 28 * n, length of Data_Record) where n = Value (Number_of_Time/Version_Entries_in_Record) RecordFieldNames: Satellite_Identifier Record_Type Instrument_Identifier Data_Subtype_Or_Species Format_Version_Number Physical_Record_Count Number_Of_Time/Version_Entries_In_Record Spare Version_Entries RecordSyntax: 9 Fields #1 : Satellite_Identifier #2 : Record_Type #3 : Instrument_Identifier #4 : Data_Subtype_Or_Species #5 : Format_Version_Number #6 : Physical_Record_Count #7 : Number_Of_Time/Version_Entries_In_Record #8 : Spare #9 : Version_Entries Fields ====== 3.1 Satellite_Identifier ------------------------ FieldName: Satellite_Identifier FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Satellite identifier. Constant value 'UARS' FieldRepresentation: 4A FieldDisplayFormat: A4 3.2 Record_Type --------------- FieldName: Record_Type FieldSyntax: ASCII Character*2 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Record type. Constant value ' 2' for a continuation label record format. FieldRepresentation: 2A FieldDisplayFormat: A2 3.3 Instrument_Identifier ------------------------- FieldName: Instrument_Identifier FieldMnemonic: Data_Type FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Instrument identifier. Left justified, blank filled. Constant value = 'PEM' FieldRepresentation: 12A FieldDisplayFormat: A12 3.4 Data_Subtype_Or_Species --------------------------- FieldName: Data_Subtype_Or_Species FieldMnemonic: Subtype FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Data subtype or species. Left justified, blank filled. The sixteen subtypes/species for PEMAXIS are: Constant value = 'EDEP3AT_P01' (for AXIS Pixel 1 file) Constant value = 'EDEP3AT_P02' (for AXIS Pixel 2 file) Constant value = 'EDEP3AT_P03' (for AXIS Pixel 3 file) Constant value = 'EDEP3AT_P04' (for AXIS Pixel 4 file) Constant value = 'EDEP3AT_P05' (for AXIS Pixel 5 file) Constant value = 'EDEP3AT_P06' (for AXIS Pixel 6 file) Constant value = 'EDEP3AT_P07' (for AXIS Pixel 7 file) Constant value = 'EDEP3AT_P08' (for AXIS Pixel 8 file) Constant value = 'EDEP3AT_P09' (for AXIS Pixel 9 file) Constant value = 'EDEP3AT_P10' (for AXIS Pixel 10 file) Constant value = 'EDEP3AT_P11' (for AXIS Pixel 11 file) Constant value = 'EDEP3AT_P12' (for AXIS Pixel 12 file) Constant value = 'EDEP3AT_P13' (for AXIS Pixel 13 file) Constant value = 'EDEP3AT_P14' (for AXIS Pixel 14 file) Constant value = 'EDEP3AT_P15' (for AXIS Pixel 15 file) Constant value = 'EDEP3AT_P16' (for AXIS Pixel 16 file) FieldRepresentation: 12A FieldDisplayFormat: A12 3.5 Format_Version_Number ------------------------- FieldName: Format_Version_Number FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Format version number. Constant value ' 1' indicates that this is the first version of the Level 3AT file structure. FieldRepresentation: 4A FieldDisplayFormat: A4 3.6 Physical_Record_Count ------------------------- FieldName: Physical_Record_Count FieldSyntax: ASCII character*8 string FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Physical record count. Constant value ' 1' indicates the label record is the logical first record in the file. FieldRepresentation: 8A FieldDisplayFormat: A8 3.7 Number_Of_Time/Version_Entries_In_Record -------------------------------------------- FieldName: Number_Of_Time/Version_Entries_In_Record FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 1 FieldDescription: Number of time/version entries in record Right justified, blank filled FieldRepresentation: 4A FieldDisplayFormat: A4 3.8 Spare --------- FieldName: Spare FieldSyntax: ASCII Character*2 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Spare. Field contents undefined FieldRepresentation: 2A FieldDisplayFormat: A2 3.9 Version_Entries ------------------- FieldName: Version_Entries FieldSyntax: ASCII Character*28 String 1-D Array (n), where n is value (Number_Of_Time/Version_Entries_In_Record) FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: List of version entries. Each version entry contains: Version_Entries (1:3) start year Version_Entries (4:6) start day of year Version_Entries (7:14) start milliseconds of day Version_Entries (15:24) version number Version_Entries (24:28) cycle number FieldRepresentation: n(28A) FieldDisplayFormat: nA28 Record ====== 4. Data_Record -------------- RecordName: Data_Record RecordStructure: Variable Length RecordLength: MAX (768, length of File_Label_Record) RecordFieldNames: Satellite_Identifier Record_Type Instrument_Identifier Physical_Record_Count Spare Total_Number_Of_Points_In_The_Record Number_Of_Actual_Points Starting_Index_Of_First_Actual_Point Record_Time_In_UDTF_Format Latitude Longitude Local_Solar_Time Solar_Zenith_Angle Data Quality RecordSyntax: 15 Fields #1 : Satellite_Identifier #2 : Record_Type #3 : Instrument_Identifier #4 : Physical_Record_Count #5 : Spare #6 : Total_Number_Of_Points_In_The_Record #7 : Number_Of_Actual_Points #8 : Starting_Index_Of_First_Actual_Point #9 : Record_Time_In_UDTF_Format #10: Latitude #11: Longitude #12: Local_Solar_Time #13: Solar_Zenith_Angle #14: Data #15: Quality Fields ====== 4.1 Satellite_Identifier ------------------------ FieldName: Satellite_Identifier FieldSyntax: ASCII Character*4 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Satellite identifier. Constant value 'UARS' FieldRepresentation: 4A FieldDisplayFormat: A4 4.2 Record_Type --------------- FieldName: Record_Type FieldSyntax: ASCII Character*2 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Record type. Constant value ' 3' for the data record format. FieldRepresentation: 2A FieldDisplayFormat: A2 4.3 Instrument_Identifier ------------------------- FieldName: Instrument_Identifier FieldMnemonic: Data_Type FieldSyntax: ASCII Character*12 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Instrument identifier. Left justified, blank filled. Constant value = 'PEM' FieldRepresentation: 12A FieldDisplayFormat: A12 4.4 Physical_Record_Count ------------------------- FieldName: Physical_Record_Count FieldSyntax: ASCII Character*8 String FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 2 FieldDescription: Physical record count. Right justified, blank filled. Does not count SFDU label record. FieldRepresentation: 8A FieldDisplayFormat: A8 4.5 Spare --------- FieldName: Spare FieldSyntax: ASCII Character*2 String FieldUnits: n/a FieldResolution: n/a FieldRange: n/a FieldDescription: Spare. Constant value '00' FieldRepresentation: 2A FieldDisplayFormat: A2 4.6 Total_Number_Of_Points_In_The_Record ---------------------------------------- FieldName: Total_Number_Of_Points_In_The_Record FieldMnemonic: Max_Points FieldSyntax: Scalar FieldUnits: n/a FieldResolution: n/a FieldRange: Constant Integer = 88 FieldDescription: Maximum number of data points in the data array. FieldRepresentation: VI4 FieldDisplayFormat: I4 4.7 Number_Of_Actual_Points --------------------------- FieldName: Number_Of_Actual_Points FieldMnemonic: Num_Points FieldSyntax: Scalar FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 1, <= 88 FieldDescription: Number of actual elements in the data array to be retrieved. FieldRepresentation: VI4 FieldDisplayFormat: I4 4.8 Starting_Index_Of_First_Actual_Point ---------------------------------------- FieldName: Starting_Index_Of_First_Actual_Point FieldMnemonic: Start_Index FieldSyntax: Scalar FieldUnits: n/a FieldResolution: n/a FieldRange: Integer >= 1, <= 88 FieldDescription: Starting index of first actual element in the DATA3A array to be retrieved. FieldRepresentation: VI4 FieldDisplayFormat: I4 4.9 Record_Time_In_UDTF_Format ------------------------------- FieldName: Record_Time_In_UDTF_Format FieldMnemonic: Strt_Dattim FieldSyntax: 1-D Array (2) FieldUnits: 1 millisecond FieldResolution: 1 millisecond FieldRange: n/a FieldDescription: Record time in UDTF format FieldRepresentation: 2VI4 FieldDisplayFormat: I5,I8 4.10 Latitude -------------- FieldName: Latitude FieldMnemonic: REF_LAT FieldSyntax: Scalar FieldUnits: Degrees FieldResolution: n/a FieldRange: Real >= -80.0, <= 80.0 FieldDescription: Geodetic latitude at the UARS reference time. Value provided by the PEM production software which represents the location where the center of the field of view of each AXIS pixel intersects a surface at 100-km altitude at a time corresponding to the center time of the averaging interval. The position and attitude of UARS are provided by O/A services. FieldRepresentation: VR4 FieldDisplayFormat: F7.3 4.11 Longitude -------------- FieldName: Longitude FieldMnemonic: REF_LONG FieldSyntax: Scalar FieldUnits: Degrees FieldResolution: n/a FieldRange: Real >= 0.0, < 360.0 FieldDescription: Geodetic longitude at the UARS reference time. Value provided by the PEM production software which represents the location where the center of the field of view of each AXIS pixel intersects a surface at 100-km altitude at a time corresponding to the center time of the averaging interval. The position and attitude of UARS are provided by O/A services. FieldRepresentation: VR4 FieldDisplayFormat: F7.3 4.12 Local_Solar_Time --------------------- FieldName: Local_Solar_Time FieldMnemonic: LST FieldSyntax: Scalar FieldUnits: Hours FieldResolution: n/a FieldRange: 0 to 24 FieldDescription: Local solar time at limb tangent point at record time, generated by UCSS Production Software Support Services. FieldRepresentation: VR4 FieldDisplayFormat: F7.3 4.13 Solar_Zenith_Angle ----------------------- FieldName: Solar_Zenith_Angle FieldMnemonic: SZA FieldSyntax: Scalar FieldUnits: Degrees FieldResolution: n/a FieldRange: 0 to 180 FieldDescription: Solar zenith angle at tangent point at record time generated by UCSS Production Software Support Services. FieldRepresentation: VR4 FieldDisplayFormat: F7.3 4.14 Data --------- FieldName: Data FieldMnemonic: DATA3A FieldSyntax: 1-D Array (n), where n is value (Total_Number_Of_Points_In_The_Record) FieldUnits: keV / (g-s) FieldResolution: variable FieldRange: 1E-28 to 1E0 FieldDescription: DATA3A is a one dimensional array where the index, offset by START_INDEX, is associated with the element number in the UARS standard altitude referenced array. FieldRepresentation: NVR4 FieldDisplayFormat: E10.2 FieldFillCode: INVALID_REAL_NUMBER X'00008000' 4.15 Quality ------------ FieldName: Quality FieldMnemonic: Qual FieldSyntax: 1-D Array (n), where n is value (Total_Number_Of_Points_In_The_Record) FieldUnits: keV /(g-s) FieldResolution: variable FieldRange: 1E-28 to 1E0 FieldDescription: One dimensional array containing quality information associated with the data values returned in DATA3A. FieldRepresentation: NVR4 FieldDisplayFormat: E10.2 FieldFillCode: INVALID_REAL_NUMBER X'00008000'