GLOBAL PRECIPITATION MEASUREMENT PRECIPITATION PROCESSING SYSTEM. File Specification AMSUBBASE. Preliminary Version

Transcription

1 GLOBAL PRECIPITATION MEASUREMENT PRECIPITATION PROCESSING SYSTEM File Specification AMSUBBASE Preliminary Version October 12, 2015

2 0.1 AMSUBBASE - AMSUB base AMSUBBASE contains brightness temperature from the AMSU-B passive microwave instrument flown on the NOAA satellites. Swath S1 is the only swath. Swath S1 contains 5 channels: /- 0.9 GHz, /- 0.9 GHz, /- 1 GHz, /- 3 GHz, /- 7 GHz. The scan period is 2.667s. The input is Level-2 AMSU-B Orbital products in HDF-EOS format archived at CLASS. All of the data of the input are included. Brightness temperature was obtained by applying the Antena Pattern Correction to the antena temperature. Please see the Microwave Surface and Precipitation Products System (MSPPS) User s Manual and NOAA KLM User s Guide for details. Dimension definitions: nscan1 var Number of Swath 1 scans in the granule. nchannel1 5 Number of Swath 1 channels. n Number of 270. npixel1 90 Number of Swath 1 pixels in one scan. nchuia1 1 Number of Swath S1 unique incidence angles. three 3 Number of spacial dimensions. Figure 1 through Figure 4 show the structure of this product. The text below describes the contents of objects in the structure, the C Structure Header File and the Fortran Structure Header File. FileHeader (Metadata): FileHeader contains metadata of general interest. This group appears in all data products. See Metadata for GPM Products for details. InputRecord (Metadata): InputRecord contains a record of input files for this granule. This group appears in Level 1, Level 2, and Level 3 orbital data products. Level 3 time averaged products have the same information separated into 3 groups since they have many inputs. See Metadata for GPM Products for details. NavigationRecord (Metadata): NavigationRecord contains navigation metadata for this granule. This group appears in Level 1, Level 2, and Level 3 orbital data products. See Metadata for GPM Products for details. FileInfo (Metadata): FileInfo contains metadata used by the PPS I/O Toolkit (TKIO). This group appears in all data products. See Metadata for GPM Products for details. baseheader (Group) TLE date (4-byte integer, array size: 6): TLE date time arrays. 1

3 FileHeader InputRecord NavigationRecord FileInfo baseheader Metadata Metadata Metadata Metadata Group SwathHeader Metadata ScanTime 19 bytes Group: nscan1 File Latitude 4 bytes Array: npixel1 x nscan1 Longitude 4 bytes Array: npixel1 x nscan1 ismissing 1 byte Array: nscan1 sunglintangle 4 bytes Array: npixel1 x nscan1 solarbetaangle 4 bytes Array: nscan1 timesinceeclipseentry 4 bytes Array: nscan1 tlepos 4 bytes Array: three x nscan1 S1 tlevel 4 bytes Array: three x nscan1 sclat 4 bytes Array: nscan1 sclon 4 bytes Array: nscan1 scalt 4 bytes Array: nscan1 TimeTAI93 8 bytes Array: nscan1 sfctype 1 byte Array: npixel1 x nscan1 orbitmode 1 byte Array: nscan1 LZangle 4 bytes Array: npixel1 x nscan1 SZangle 4 bytes Array: npixel1 x nscan1 continued on next figure Figure 1: Data Format Structure for AMSUBBASE, AMSUB base 2

4 continued from last figure Chan1BT 4 bytes Array: npixel1 x nscan1 Chan2BT 4 bytes Array: npixel1 x nscan1 Chan3BT 4 bytes Array: npixel1 x nscan1 S1 Chan4BT 4 bytes Array: npixel1 x nscan1 Chan5BT 4 bytes Array: npixel1 x nscan1 RR 4 bytes Array: npixel1 x nscan1 Snow 4 bytes Array: npixel1 x nscan1 IWP 4 bytes Array: npixel1 x nscan1 SWE 4 bytes Array: npixel1 x nscan1 SFR 4 bytes Array: npixel1 x nscan1 Figure 2: Data Format Structure for AMSUBBASE, AMSUB base TLE date 4 bytes Array: 6 TLE time 8 bytes Array: 1 baseheader accf 8 bytes Array: nchannel1 x n270 Bspace 8 bytes Array: nchannel1 wavenumber 4 bytes Array: nchannel1 Figure 3: Data Format Structure for AMSUBBASE, baseheader Year 2 bytes Array: nscan1 Month 1 byte Array: nscan1 DayOfMonth 1 byte Array: nscan1 Hour 1 byte Array: nscan1 ScanTime Minute 1 byte Array: nscan1 Second 1 byte Array: nscan1 MilliSecond 2 bytes Array: nscan1 DayOfYear 2 bytes Array: nscan1 SecondOfDay 8 bytes Array: nscan1 Figure 4: Data Format Structure for AMSUBBASE, ScanTime 3

5 TLE time (8-byte float, array size: 1): TLE time as in two line element. accf (8-byte float, array size: nchannel1 x n270): The correction due to angular dependence of reflectivity. Bspace (8-byte float, array size: nchannel1): The channel offset derived from deep space calibration. wavenumber (4-byte float, array size: nchannel1): Wave number. S1 (Swath) SwathHeader (Metadata): SwathHeader contains metadata for swaths. This group appears in Level 1 and Level 2 data products. See Metadata for GPM Products for details. ScanTime (Group) A UTC time associated with the scan. Year (2-byte integer, array size: nscan1): 4-digit year, e.g., Values range from 1950 to 2100 years. Special values are defined as: Missing value Month (1-byte integer, array size: nscan1): Month of the year. Values range from 1 to 12 months. Special values are defined as: -99 Missing value DayOfMonth (1-byte integer, array size: nscan1): Day of the month. Values range from 1 to 31 days. Special values are defined as: -99 Missing value Hour (1-byte integer, array size: nscan1): UTC hour of the day. Values range from 0 to 23 hours. Special values are defined as: -99 Missing value Minute (1-byte integer, array size: nscan1): Minute of the hour. Values range from 0 to 59 minutes. Special values are defined as: -99 Missing value Second (1-byte integer, array size: nscan1): Second of the minute. Values range from 0 to 60 s. Special values are defined as: -99 Missing value 4

6 MilliSecond (2-byte integer, array size: nscan1): Thousandths of the second. Values range from 0 to 999 ms. Special values are defined as: Missing value DayOfYear (2-byte integer, array size: nscan1): Day of the year. Values range from 1 to 366 days. Special values are defined as: Missing value SecondOfDay (8-byte float, array size: nscan1): A time associated with the scan. scantime sec is expressed as the UTC seconds of the day. Values range from 0 to s. Special values are defined as: Latitude (4-byte float, array size: npixel1 x nscan1): The earth latitude of the center of the IFOV at the altitude of the earth ellipsiod. Latitude is positive north, negative south. Values range from -90 to 90 degrees. Special values are defined as: Longitude (4-byte float, array size: npixel1 x nscan1): The earth longitude of the center of the IFOV at the altitude of the earth ellipsiod. Longitude is positive east, negative west. A point on the 180th meridian has the value -180 degrees. Values range from -180 to 180 degrees. Special values are defined as: ismissing (1-byte integer, array size: nscan1): Missing scan flag. sunglintangle (4-byte float, array size: npixel1 x nscan1): sunglintangle is the angular separation between the Reflected Satellite View Vector and the Sun Vector. When sunglintangle is zero, the instrument views the center of the specular (mirror-like) sun reflection. solarbetaangle (4-byte float, array size: nscan1): Sun direction elevation from the orbit plane, positive toward orbit normal which is given by the cross product of the spacecraft position and velocity vectors. Values range from to 59.0 degrees. Special values are defined as: timesinceeclipseentry (4-byte float, array size: nscan1): The estimated duration in seconds since the last entry into the Earth s shadow. tlepos (4-byte float, array size: three x nscan1): Spacecraft position at the ScanTime. Values are in m. Special values are defined as: tlevel (4-byte float, array size: three x nscan1): Spacecraft velocity at the ScanTime. Values are in m/s. Special values are defined as: 5

7 sclat (4-byte float, array size: nscan1): Spacecraft latitude at the ScanTime. Values range from -90 to 90.0 degree. Special values are defined as: sclon (4-byte float, array size: nscan1): Spacecraft longitude at the ScanTime. Values range from -180 to degree. Special values are defined as: scalt (4-byte float, array size: nscan1): Spacecraft altitude at the ScanTime. Values range from 0 to 1000 km. Special values are defined as: TimeTAI93 (8-byte float, array size: nscan1): Number of seconds since 0000 Jan 1, sfctype (1-byte integer, array size: npixel1 x nscan1): Surface type: 0=ocean, 1=land, 2=coast orbitmode (1-byte integer, array size: nscan1): Orbit direction: 1=ascending 2=descending. LZangle (4-byte float, array size: npixel1 x nscan1): Local zenith angle. Values range from -60 to 60 degrees. Special values are defined as: SZangle (4-byte float, array size: npixel1 x nscan1): Solar zenith angle. Not sure about the range and units. Chan1BT (4-byte float, array size: npixel1 x nscan1): Channel 1 brightness Temperature. Chan2BT (4-byte float, array size: npixel1 x nscan1): Channel 2 brightness Temperature. Chan3BT (4-byte float, array size: npixel1 x nscan1): Channel 3 brightness Temperature. Chan4BT (4-byte float, array size: npixel1 x nscan1): Channel 4 brightness Temperature. Chan5BT (4-byte float, array size: npixel1 x nscan1): Channel 5 brightness Temperature. RR (4-byte float, array size: npixel1 x nscan1): Rain rate. Snow (4-byte float, array size: npixel1 x nscan1): Snow cover. IWP (4-byte float, array size: npixel1 x nscan1): Ice water path. 6

8 SWE (4-byte float, array size: npixel1 x nscan1): Snow water equivalent. SFR (4-byte float, array size: npixel1 x nscan1): Snow fall rate. C Structure Header file: #ifndef _TK_AMSUBBASE_H_ #define _TK_AMSUBBASE_H_ #ifndef _SCANTIME_ #define _SCANTIME_ typedef struct { short Year; signed char Month; signed char DayOfMonth; signed char Hour; signed char Minute; signed char Second; short MilliSecond; short DayOfYear; double SecondOfDay; } SCANTIME; #endif #ifndef _LAMSUBBASE_S1_ #define _LAMSUBBASE_S1_ typedef struct { SCANTIME ScanTime; float Latitude[90]; float Longitude[90]; signed char ismissing; float sunglintangle[90]; float solarbetaangle; float timesinceeclipseentry; float tlepos[3]; float tlevel[3]; float sclat; float sclon; float scalt; 7

9 double TimeTAI93; signed char sfctype[90]; signed char orbitmode; float LZangle[90]; float SZangle[90]; float Chan1BT[90]; float Chan2BT[90]; float Chan3BT[90]; float Chan4BT[90]; float Chan5BT[90]; float RR[90]; float Snow[90]; float IWP[90]; float SWE[90]; float SFR[90]; } LAMSUBBASE_S1; #endif #ifndef _LAMSUBBASE_BASEHEADER_ #define _LAMSUBBASE_BASEHEADER_ typedef struct { int TLE_date[6]; double TLE_time[1]; double accf[270][5]; double Bspace[5]; float wavenumber[5]; } LAMSUBBASE_BASEHEADER; #endif #endif Fortran Structure Header file: STRUCTURE /SCANTIME/ INTEGER*2 Year BYTE Month BYTE DayOfMonth BYTE Hour BYTE Minute BYTE Second 8

10 INTEGER*2 MilliSecond INTEGER*2 DayOfYear REAL*8 SecondOfDay END STRUCTURE STRUCTURE /LAMSUBBASE_S1/ RECORD /SCANTIME/ ScanTime REAL*4 Latitude(90) REAL*4 Longitude(90) BYTE ismissing REAL*4 sunglintangle(90) REAL*4 solarbetaangle REAL*4 timesinceeclipseentry REAL*4 tlepos(3) REAL*4 tlevel(3) REAL*4 sclat REAL*4 sclon REAL*4 scalt REAL*8 TimeTAI93 BYTE sfctype(90) BYTE orbitmode REAL*4 LZangle(90) REAL*4 SZangle(90) REAL*4 Chan1BT(90) REAL*4 Chan2BT(90) REAL*4 Chan3BT(90) REAL*4 Chan4BT(90) REAL*4 Chan5BT(90) REAL*4 RR(90) REAL*4 Snow(90) REAL*4 IWP(90) REAL*4 SWE(90) REAL*4 SFR(90) END STRUCTURE STRUCTURE /LAMSUBBASE_BASEHEADER/ INTEGER*4 TLE_date(6) REAL*8 TLE_time(1) REAL*8 accf(5,270) REAL*8 Bspace(5) REAL*4 wavenumber(5) END STRUCTURE 9