NOAA KLM User's Guide

Section 9.3.1.1

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9.3.1.1 Primary Components 37 Day File (PC37DF)

This is the basic output file generated by the RBPGS and is known as the Primary Components 37 Day File (PC37DF). It is a revolving file with, at present, one record for a header plus a set of records for each of 37 day bins. The Primary Components File has a logical record size of 23,476 bytes with one record per block. The file format is ASCII for text information and integer (I*2) for the data. Each day bin contains three sets of maps:

1. Nighttime (22 maps),
2. Daylight longwave (22 maps),
3. Daylight shortwave (24 maps).

Each set of maps occurs in pairs, one map for the Northern Hemisphere and one for the Southern Hemisphere (thus the nighttime maps consist of eleven types). Each of these requires two records. The structure of an individual map is based on the Pathfinder Equal Areas/Equal (EAA) map. The whole RBPGS is set up to, at any time, either add or subtract data from any day bin within the PC37DF. This is done so as to allow reprocessing of poor data. The file is fully described in Table 9.3.1.1-1. Note, the tabulated Available Solar Energy (ASE) Day Bin Fields are stored contiguously (all 600) in the header and are allocated to each Day Bin.

Table 9.3.1.1-1. Description of the Primary Components 37 Day File (PC37DF) Header.
Field Bytes Type Description
HEADER 1-100 A100 ASCII Header "NOAA/NESDIS RADIATION BUDGET ARCHIVED 37-DAY PRIMARY COMPONENTS FILE PRD.RADBUD.NOAAXX.ARC.DAY37CMP" where XX indicates the satellite used.
TYPE 101-102 I*2 The type of file (0 for Primary components file).
VER 103-104 I*2 The version number of the file (0 for this version).
SATID 105-106 I*2 The satellite ID.
PCOY 107-108 I*2 The year of the oldest data contained in the file.
PCOM 109-110 I*2 The month of the oldest data contained in the file.
PCOD 111-112 I*2 The day of the month of the oldest data contained in the file.
PCYY 113-114 I*2 The 4 digit year of the youngest (most current) data in the file.
PCYM 115-116 I*2 The month of the youngest (most current) data in the file.
PCYD 117-118 I*2 The day of the month of the youngest (most current) data in the file.
PCDBO 119-120 I*2 The day bin reflecting the oldest data in the file.
PCDBY 121-122 I*2 The day bin reflecting the youngest (most current) data in the file.
PCDBSR 123-124 I*2 The first physical record on this file that contains Primary Components map data for day bin number 1.
PCDBBL 125-126 I*2 The total number of physical records in this file that are required by each day bin.
IDATE 127-132 3 I*2 The creation date of this file (YYYYMMDD).
RECTYP 133-134 I*2 The record type of this (header) record (=1).
EPOCHY 135-136 I*2 The satellite epoch year (launch year).
EPOCHD 137-138 I*2 The satellite epoch day-in-year (launch day).
MAPTYP 139-140 I*2 The map type (0=PSG maps, 1=EAA maps).
ASPECT 141-142 I*2 EAA map aspect ratio x 1000.
AREA 143-144 I*2 EAA map nominal element area (square degrees x 1000).
CSCALE 145-148 I*4 Polar Stereographic (PSG) map scale (grid points x 1000 between pole and equator).
LRC 149-150 I*2 Longitude Rotation Convention (LRC).
PRIMEL 151-152 I*2 PSG map Prime Longitude x 100 (interpreted via the LRC).
PACK 153-154 I*2 Is the map to be packed? If yes, then PACK=1. Note that EAA maps are packed.
NPROWS 155-156 I*2 If so, then number of rows per stored column.
SBOUND(1-5) 157-166 5I*2 GAC 5 shortwave class boundary fluxes for the GAC histograms. These values have to be the same as those held in SF/RF 18 and in the RDAF header (the sixth value is immaterial).
LBOUND(1-5) 167-176 5I*2 GAC 5 longwave class boundary fluxes for the GAC histograms. These values have to be the same as those held in SF/RF 18 and in the RDAF header (the sixth value is immaterial).
TSTAMP 177-188 6I*2 Time stamp written at the end of ANLRET/SUMFRM as YYYYMMDDHHMMSS.
NDHELD 189-190 I*2 Number of days in the 37(!) Day files. This is to be the same as RADANL:DBNX.
PRL 191-194 I*4 Primary Components 37 Day File physical record length (23,476 bytes for this version).
  195-276   Spare.
Tabulated ASE Day Bin Fields
ABDN 277+(ADBN-1)*600:278+(ADBN-1)*600 I*2 Permanent Day Bin label. Values 1 to 37 (or RADANL:DBNX the number of day bins in the 37(!) day files).
NCDAY 279+ADBN-1)*600:280+(ADBN-1)*600 I*2 Actual Day Number of the contained data relative to the Satellite Epoch.
NARUNS 281+(ADBN-1)*600:282+(ADBN-1)*600 I*2 Number of RADRET runs involved in the ASETAB average.
IDATIM (1-6) <283+(ADBN-1)*600:294+(ADBN-1)*600 6 I*2 Time Stamp YYMMDDHHMMSS

ASETAB (1-91) 295+(ADBN-1)*600:476+(ADBN-1)*600   Contains the Biased Sum of Average Available Solar Energy (ASE) Table for the actual day currently occupying the day bin. There are 91 values (two bytes each) in each field starting at the North Pole and then given at intervals of two degrees. Each value should be divided by the number of pixels in a target (currently 121). Then add the shortwave bias value (currently 270) to retrieve the average unbiased ASE value for each latitude.
  477+(ADBN-1)*600:876+(ADBN-1)*600   Spare.
  22077-23476   Spare.

The first map data containing record on the Primary Components file is the first data record of Day Bin 1 and is Record Number PCDBSR (see Table 9.3.1.1-1). If PCDBSR is set higher than 2, then an extended header may be constructed running from record 2 to PCDBSR-1.

Day Bin 1 runs from Record PCDBSR through Record PCDBBL + PCDBSR - 1 , i.e., there are PCDBBL records allocated to day bin 1 and, thereafter, to every day bin. The records in each day bin are constructed in exactly the same manner with the only difference being the Permanent Day Bin label, DBN, located in bytes one and two of each record, allocated to the given day bin. Day Bin 2, etc. is structured exactly the same as Day Bin 1 (apart from the value of DBN) and immediately follows Day Bin 1.

In a Day Bin, the records occur in groups of four, all pertaining to the same kind of map field (e.g., GAC OLR at night); two records for the Northern Hemisphere followed directly by two records for the Southern Hemisphere. The format of the first record of a hemisphere pair is described in Table 9.3.1.1-2, while the second record of a hemisphere pair is contained in Table 9.3.1.1-3.

Table 9.3.1.1-2. Format of Record 1 of a Hemisphere Pair in a Day Bin.
Field Bytes Type Description
DBN 1-2 I*2 Permanent Day Bin label.
BCDAY 3-4 I*2 Actual Day Number, relative to the Satellite Epoch, of the data that is currently stored in the day bin.
YEAR 5-6 I*2 Actual four digit year.
MONTH 7-8 I*2 Actual month.
DAY 9-10 I*2 Actual day of month.
PURGET 11-12 I*2 Last purge date (=100 x month + day, with month and day being the real-time month and day of the first writing of the BCDAY data).
RCTYPE 13-14 I*2 '02' 1st record of a Northern Hemisphere map. '04' 1st record of a Southern Hemisphere map.
DBSECN 15-16 I*2 Day Bin Section Number:
1= Night;
2= Longwave Day;
3= Shortwave Day.
FIELD 17-18 I*2 Field mnemonic. (See Table 9.3.1.1-4.)
NORS 19-20 I*2 Hemisphere:
North=0,
South=1.
TSTAMP 21-32 6 I*2 Time Stamp as 'YYYYMMDDHHMMSS' of most recent data addition or subtraction.
NARUNS 33-34 I*2 Showing the number of RADRET runs contributing to the tabulated Available Solar Energy (ASE). Copied from the PC37DF header.
ASEBYT 35-216   Showing the Biased Sum of Tabulated ASE for the (1-91) actual day, starting at the North Pole and then given for every two degrees latitude. Copied from the PC37DF header.
SPARE 217-276   Spare
I*2MAP 277-23,476   Showing the first 11,600 I*2 elements of the Equal Areas/Equal Aspect Pathfinder Map (of total size 20,626 elements) for the hemisphere. The first set of elements (3) is for the pole. The second latitude band of elements (9) is for -89 in the Southern Hemisphere and 89 for the Northern Hemisphere. This continues toward the equator, where the number of elements in each latitude band is determined by the array NCELL (see second hemisphere pair). The first element in a latitude set is the eastward most longitude (beginning at the Greenwich Meridian). Each element after that is west of the previous element in the latitude set.

Table 9.3.1.1-3. Format of Record 2 of a Hemisphere Pair of a Day Bin.
Field Bytes Type Description
DBN 1-2 I*2 Permanent Day Bin label.
FIELD 3-4 I*2 Field mnemonic (See Table 9.3.1.1-4).
NORS 5-6 I*2 Hemisphere:
North=0;
South=1.
NCELL (1-90) 7-186 90 I*2 Each succeeding value represents the number of longitude bins in each of 90 latitude bands of the (current) Equal Areas/Equal Aspect Pathfinder Maps starting at the pole and abutting (to the west) the Greenwich Meridian.
I2MAP 277-18,328   Showing the remaining 9,026 elements (11,601-20,626) of the EAA map stored as 20,626 I*2 integers.
  18,329-22,036   Spare
E2MAP 22,037-23,476   Showing the 720 I*2 elements of the equatorial band data for the hemisphere. Each element is for use with the old-style 144 by 72 LatLon maps, and is of size 1.25 degrees in latitude and 0.5 degrees in longitude with each element abutting the equator and the first element centered on the dateline. Subsequent elements are recorded eastwards.

Table 9.3.1.1-4. Field Mnemonic for radiation budget monthly mean data.
Data Field Description
HCN=1 HIRS Count Nighttime
HN=2 HIRS OLR Nightime
GCN=3 GAC Count Nighttime
GLN=4 GAC Longwave Nighttime
GQN=5 GAC OLR Variance Nighttime
G1N=6 GAC OLR Class 1 Pixel Count
G2N=7 GAC OLR Class 2 Pixel Count
G3N=8 GAC OLR Class 3 Pixel Count
G4N=9 GAC OLR Class 4 Pixel Count
G5N=10 GAC OLR Class 5 Pixel Count
G6N=11 GAC OLR Class 6 Pixel Count
HCD=12 HIRS Count Daytime
HD=13 HIRS OLR Daytime
GCD=14 GAC Count Daytime
GLD=15 GAC OLR Daytime
GQD=16 GAC Variance Daytime
G1D=17 GAC OLR Daytime Class 1 Pixel Count
G2D=18M GAC OLR Daytime Class 2 Pixel Count
G3D=19 GAC OLR Daytime Class 3 Pixel Count
G4D=20 GAC OLR Daytime Class 4 Pixel Count
G5D=21 GAC OLR Daytime Class 5 Pixel Count
G6D=22 GAC OLR Daytime Class 6 Pixel Count
TC=23 Target Count in Daylight (good retrievals only)
AS=24 Average Available Solar Energy Flux
GC=25 GAC Pixel Count in Daylight
GS=26 Average GAC Absorbed SW Flux
GQ=27 Average GAC Absorbed SW Variance
G1=28 GAC Absorbed SW Class 1 Pixel Count
G2=29 GAC Absorbed SW Class 2 Pixel Count
G3=30 GAC Absorbed SW Class 3 Pixel Count
G4=31 GAC Absorbed SW Class 4 Pixel Count
G5=32 GAC Absorbed SW Class 5 Pixel Count
G6=33 GAC Absorbed SW Class 6 Pixel Count
CP=34 Experimental Cloud Product

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