CCSD1Z00000100000052CCSD1R00000300000032 DELIMITER=EOF; TYPE=CCSD1F000001; CCSD1C00000400000078 ADI=NURSIS11; SUD=NURSIS01; SUD=NURSUC01; SUD=NURSUC02; SUD=NURSUC03; SUD=NURSUC05; CCSD1R00000300000032 DELIMITER=EOF; TYPE=CCSD1D000002; ISAMS LEVEL3A DATA STRUCTURE in UARS STANDARD DOCUMENTATION FORMAT VERSION_NUMBER: 4.00 WHOLE DATA SET ============== DATA_SET_NAME: ISAMS_Level3A_Data DATA_SOURCE: Satellite/Instrument = UARS/ISAMS UARS = Upper Atmosphere Research Satellite ISAMS = Improved Stratospheric And Mesospheric Sounder SCIENTIFIC_CONTACT: Prof. Frederic W. Taylor Atmospheric, Oceanic and Planetary Physics Oxford University, Clarendon Laboratory, Parks Rd, Oxford, OX1 3PU, England Phone: 44-865-272933 E-Mail: TAYLOR@ATM.OX.AC.UK SOURCE_CHARACTERISTICS: Refer to NURSIS01 INVESTIGATION_OBJECTIVES: Refer to NURSIS01 INSTRUMENT_ATTRIBUTES: Refer to NURSIS01 MEASURED_PARAMETERS: Refer to NURSIS01 The only differences in coverage between Level 2 and Level 3A data are in horizontal and vertical resolution: Horizontal Resolution: 400 km along-track for 3AT/3TP files, 4 deg lat. for 3AL/3LP files. Vertical Resolution: Profiles are on UARS Pressure Surfaces, defined as p(mb) = 1000.0 * 10.0**(-i/6) for i=0,1,... This gives increments -ln(p)=0.38 scale heights, or approx 2.5km between profile surfaces. DATA_SET_QUALITY: [Error estimates for each parameter are tbd] Systematic errors in the measurements and the retrievals are expected to change with the operating mode of the instrument. While profiles may safely be combined (e.g. gridded) from within any single data mode, or from data modes representing the same instrument operating mode, systematic differences may occur between profiles from data modes representing different instrument modes. In some cases these differences may be instrumental. One obvious example is if the pressure of one of the PMC cells is changed: this changes the retrieval weighting functions, and therefore the relative influences of the a priori (climatology) and the measurements in the retrieved product. A PMC for one channel may have a knock-on effect on other species; e.g. the CO2 PMCs are used for temperature and pressure determination, so affect all retrieved products. Hence a change of pressure in the CH4 PMC could affect N2O retrievals and vice-versa since the spectra of the two gases overlap and the retrievals are interlinked. One aspect of operation which is considered to distinguish one mode from another is whether the instrument is viewing to the +Y or -Y side. This should have little effect on the instrument biases, but the local time at the +Y and -Y tangent points normally differs by several hours. Hence it would be inappropriate to grid or other combine profiles for species which have a large diurnal variation without taking allowing for such effects. Information about the instrument operating mode is provided in the level 3 parameter files. In addition information about the line of sight direction and solar angles are provided, and may be of assistance in interpreting data from the photochemically active species. DATA_PROCESSING_OVERVIEW: ISAMS Level 3A data are generated by interpolating the ISAMS Level 2 profiles to standard UARS surfaces (using the Level 2 pressure files) then interpolating along the tangent track to standard output times (3AT files) or latitude crossings (3AL files). Associated with each 3A data file is a parameter file (3TP with 3AT, 3LP with 3AL), containing additional information on ISAMS operation conditions for each data profile, parameters which are not accomodated in the standard UARS 3A data format. Level 3ALP data are generated from ISAMS Level 2 Data files at the same time as Level 3AL data files. Where appropriate the values contained in Level 3ALP (and also 3AL) are derived from the level 2 profiles by linear interpolation in observation time between adjacent profiles. This is necessary because the Level 2 profiles are provided at fixed times where the Level 3AL products are required at fixed latitudes. No attempt is made to interpolate between successive profiles that are in different 'modes' (see DATA_SET_QUALITY). DATA_USAGE: ISAMS 3A profiles have been interpolated both vertically, and horizontally from the original retrieval locations (Level 2 profiles) to the standard surfaces and locations defined by the UARS project for all limb-viewing instruments. The 3A format is also common to all UARS instruments so the 3A data set is ideal for intercomparisons of profiles although it should be remembered that it represents a degradation of the original ISAMS retrievals. The 3AT/3TP data are DEC Direct Access files, with each record in time order spaced at intervals of 1 UARS minute (65.536 secs), or approximately 400km along the tangent track. It should be remembered that ISAMS is a two-sided viewing instrument so that the 3AT profiles may not lie along a continuous track throughout an orbit. The 3AL/3LP data are DEC Keyed Access files, where the record key contains coded information on both latitude and time (see NURSUC02, NURSUC05 for details of the encoding). Each record contains a profile at the intersection of the tangent track with a 4 degree multiple of latitude. These files are convenient for generating zonal mean fields, although use of the 3B data is recommended. Information on ISAMS viewing side and other relevant details are contained in the parameter files (3TP,3LP). DATA_ORGANISATION: There are 4 3A files per ISAMS species per day: one each of file classes 3AT, 3AL, 3TP and 3LP. FILE_CLASS_RELATIONSHIPS: There are 4 file classes within the ISAMS 3A Dataset: 3AT, 3AL, 3TP and 3LP. The 3TP files contain parameter records matching each profile in the 3AT files. The 3LP files contain parameter records matching each profile in the 3AL files. The generic format of UARS 3A files is described in the following: NURSUC01 UARS 3TP Files NURSUC02 UARS 3LP Files NURSUC03 UARS 3AT Files NURSUC05 UARS 3AL Files LIT_REFERENCES: refer to NURSIS01 The following ISAMS-specific modifications apply to all the UARS 3A format descriptions. FILE CLASS (refer to NURSUC01 with the following modifications) ========== FILE_CLASS_NAME: ISAMS_Level3TP_Data 1.3 Ti_Field ------------ FIELD_RANGE: Constant value = 'NURS1I00xxxx' 2.3 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS' 2.4 Data_Subtype_Or_Spec ------------------------ FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', or 'TEMP'. 3.3 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. 3.4 Data_Subtype_Or_Species --------------------------- FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', or 'TEMP'. 4. Data_Record -------------- RECORD_FIELD_NAMES: Satellite_Identifier Record_Type Instrument_Identifier Physical_Record_Count Spare Maximum_Number_Of_32-bit_Words_In_The_Record Number_Of_Actual_32-bit_Words_In_The_Record Spare Record_Time_In_UDTF_Format Latitude Longitude Spare Number_Of_32-bit_Parameter_Words Satellite_Direction Sun_View_Direction PMC_Pressure_Codes Scan_Program_ID View_Direction RECORD_SYNTAX: 18 Fields #1 : Satellite_Identifier #2 : Record_Type #3 : Instrument_Identifier #4 : Physical_Record_Count #5 : Spare #6 : Maximum_Number_Of_32-bit_Words_In_The_Record #7 : Number_Of_Actual_32-bit_Words_In_The_Record #8 : Spare #9 : Record_Time_In_UDTF_Format #10: Latitude #11: Longitude #12: Spare #13: Number_Of_32-bit_Parameter_Words #14: Satellite_Direction #15: Sun_View_Direction #16: PMC_Pressure_Codes #17: Scan_Program_ID #18: View_Direction 4.3 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. 4.6 Maximum_Number_Of_32-bit_Words_In_The_Record ------------------------------------------------ FIELD_RANGE: Constant value = 4 4.7 Number_Of_Actual_32-bit_Words_In_The_Record ----------------------------------------------- FIELD_RANGE: Constant value = 4 4.13 Number_Of_32-bit_Parameter_Words ------------------------------------- FIELD_RANGE: Constant value = 4 4.14 Satellite_Direction ------------------------ FIELD_NAME: Satellite_Direction FIELD_MNEMONIC: SDIRECT FIELD_SYNTAX: Scalar FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: 0,1,2 FIELD_DESCRIPTION: Satellite direction: 0=undetermined, 1=northbound, 2=southbound FIELD_REPRESENTATION: VI1 FIELD_DISPLAY_FORMAT: I1 FIELD_FILL_CODE: '80'X 4.15 LR_View_Direction ---------------------- FIELD_NAME: Sun_View_Direction FIELD_MNEMONIC: SUNVIEW FIELD_SYNTAX: Scalar FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: 0,1,2 FIELD_DESCRIPTION: Indicates whether ISAMS is viewing towards +Y or -Y; 1 for +Y (antisun) view, 2 for -Y (sun), 0 undetermined FIELD_REPRESENTATION: VI1 FIELD_DISPLAY_FORMAT: I1 FIELD_FILL_CODE: '80'X 4.16 PMC_Pressure_Codes ----------------------- FIELD_NAME: PMC_Pressure_Codes FIELD_MNEMONIC: PMCPID FIELD_SYNTAX: 1-D Array (0:7) FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: 0-9 FIELD_DESCRIPTION: PMC nominal operating pressure codes (1-9) for each of the 8 Pressure Modulators that affect this retrieval product; 0 indicates that this PMC does not affect the product in this profile; nominal pressures corresponding to these codes are TBD. FIELD_REPRESENTATION: 8VI1 FIELD_DISPLAY_FORMAT: 8I1 FIELD_FILL_CODE: '80'X 4.17 Scan_Program_ID -------------------- FIELD_NAME: Scan_Program_ID FIELD_MNEMONIC: PRCIDM FIELD_SYNTAX: Scalar FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: >0 FIELD_DESCRIPTION: Scan program ID for this mode. 5 least significant bits are version number; remainder is program number FIELD_REPRESENTATION: VI2 FIELD_DISPLAY_FORMAT: I5 FIELD_FILL_CODE: '8000'X 4.18 Line_of_Sight_Direction ---------------------------- FIELD_NAME: Line_of_Sight_Direction FIELD_MNEMONIC: LOS FIELD_SYNTAX: Scalar FIELD_UNITS: degrees/100 FIELD_RESOLUTION: 0.01 degrees FIELD_RANGE: -18000 to +18000 FIELD_DESCRIPTION: Angle between northward meridian and Line-of-sight direction at the reference tangent point (+ve values indicate LOS direction to east, i.e. satellite to west). FIELD_REPRESENTATION: VI2 FIELD_DISPLAY_FORMAT: I6 FIELD_FILL_CODE: '8000'X FILE CLASS (refer to NURSUC02 with the following modifications) ========== FILE_CLASS_NAME: ISAMS_Level3LP_Data 1.3 Ti_Field ------------ FIELD_RANGE: Constant value = 'NURS1I00xxxx' 2.4 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS' 2.5 Data_Subtype_Or_Spec ------------------------ FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', or 'TEMP'. 3.4 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. 3.5 Data_Subtype_Or_Species --------------------------- FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', 'TEMP'. 4. Data_Record -------------- RECORD_FIELD_NAMES: Record_key Satellite_Identifier Record_Type Instrument_Identifier Physical_Record_Count Spare Maximum_Number_Of_32-bit_Words_In_The_Record Number_Of_Actual_32-bit_Words_In_The_Record Spare Record_Time_In_UDTF_Format Latitude Longitude Spare Number_Of_32-bit_Parameter_Words Satellite_Direction Sun_View_Direction PMC_Pressure_Codes Scan_Program_ID View_Direction RECORD_SYNTAX: 19 Fields #1 : Record_key #2 : Satellite_Identifier #3 : Record_Type #4 : Instrument_Identifier #5 : Physical_Record_Count #6 : Spare #7 : Maximum_Number_Of_32-bit_Words_In_The_Record #8 : Number_Of_Actual_32-bit_Words_In_The_Record #9 : Spare #10: Record_Time_In_UDTF_Format #11: Latitude #12: Longitude #13: Spare #14: Number_Of_32-bit_Parameter_Words #15: Satellite_Direction #16: Sun_View_Direction #17: PMC_Pressure_Codes #18: Scan_Program_ID #19: View_Direction 4.4 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. 4.7 Maximum_Number_Of_32-bit_Words_In_The_Record ------------------------------------------------ FIELD_RANGE: Constant value = 4 4.8 Number_Of_Actual_32-bit_Words_In_The_Record ----------------------------------------------- FIELD_RANGE: Constant value = 4 4.14 Number_Of_32-bit_Parameter_Words ------------------------------------- FIELD_RANGE: Constant value = 4 4.15 Satellite_Direction ------------------------ FIELD_NAME: Satellite_Direction FIELD_MNEMONIC: SDIRECT FIELD_SYNTAX: Scalar FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: 0,1,2 FIELD_DESCRIPTION: Satellite direction: 0=undetermined, 1=northbound, 2=southbound FIELD_REPRESENTATION: VI1 FIELD_DISPLAY_FORMAT: I1 FIELD_FILL_CODE: '80'X 4.16 LR_View_Direction ---------------------- FIELD_NAME: Sun_View_Direction FIELD_MNEMONIC: SUNVIEW FIELD_SYNTAX: Scalar FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: 0,1,2 FIELD_DESCRIPTION: Indicates whether ISAMS is viewing towards +Y or -Y; 1 for +Y (antisun) view, 2 for -Y (sun), 0 undetermined FIELD_REPRESENTATION: VI1 FIELD_DISPLAY_FORMAT: I1 FIELD_FILL_CODE: '80'X 4.17 PMC_Pressure_Codes ----------------------- FIELD_NAME: PMC_Pressure_Codes FIELD_MNEMONIC: PMCPID FIELD_SYNTAX: 1-D Array (0:7) FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: 0-9 FIELD_DESCRIPTION: PMC nominal operating pressure codes (1-9) for each of the 8 Pressure Modulators that affect this retrieval product; 0 indicates that this PMC does not affect the product in this profile; nominal pressures corresponding to these codes are TBD. FIELD_REPRESENTATION: 8VI1 FIELD_DISPLAY_FORMAT: 8I1 FIELD_FILL_CODE: '80'X 4.18 Scan_Program_ID -------------------- FIELD_NAME: Scan_Program_ID FIELD_MNEMONIC: PRCIDM FIELD_SYNTAX: Scalar FIELD_UNITS: n/a FIELD_RESOLUTION: n/a FIELD_RANGE: >0 FIELD_DESCRIPTION: Scan program ID for this mode. 5 least significant bits are version number; remainder is program number FIELD_REPRESENTATION: VI2 FIELD_DISPLAY_FORMAT: I5 FIELD_FILL_CODE: '8000'X 4.19 Line_of_Sight_Direction ---------------------------- FIELD_NAME: Line_of_Sight_Direction FIELD_MNEMONIC: LOS FIELD_SYNTAX: Scalar FIELD_UNITS: degrees/100 FIELD_RESOLUTION: 0.01 degrees FIELD_RANGE: -18000 to +18000 FIELD_DESCRIPTION: Angle between northward meridian and Line-of-sight direction at the reference tangent point (+ve values indicate LOS direction to east, i.e. satellite to west). FIELD_REPRESENTATION: VI2 FIELD_DISPLAY_FORMAT: I6 FIELD_FILL_CODE: '8000'X FILE CLASS (refer to NURSUC03 with the following modifications) ========== FILE_CLASS_NAME: ISAMS_Level3AT_Data 1.3 Ti_Field ------------ FIELD_RANGE: Constant value = 'NURS1I00xxxx' 2.3 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS' 2.4 Data_Subtype_Or_Spec ------------------------ FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', 'TEMP'. 3.3 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. 3.4 Data_Subtype_Or_Species --------------------------- FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', or 'TEMP'. 4.3 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. FILE CLASS (refer to NURSUC05 with the following modifications) ========== FILE_CLASS_NAME: ISAMS_Level3AL_Data 1.3 Ti_Field ------------ FIELD_RANGE: Constant value = 'NURS1I00xxxx' 2.4 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS' 2.5 Data_Subtype_Or_Spec ------------------------ FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', 'TEMP'. 3.4 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'. 3.5 Data_Subtype_Or_Species --------------------------- FIELD_RANGE: 'AERO12P1', 'CH4', 'CO', 'H2O', 'HNO3', 'N2O', 'N2O5', 'NO', 'NO2', 'O3', or 'TEMP'. 4.4 Instrument_Identifier ------------------------- FIELD_RANGE: Constant value = 'ISAMS'.