KSEC1 element Contents GRIB octet Recommended GRIB_API keys
 Coded GRIB_API keys
 Comments
37 
ECMWF local GRIB use definition identifier.
13 = Wave 2D spectra direction and frequency.
41 localDefinitionNumber
 localDefinitionNumber
  
38 Class 42 class
 marsClass
  
39 Type 43 type
 marsType
  
40 Stream 44-45 stream
 marsStream
  
41 
Version number or experiment identifier.
(4 ASCII characters, right justified)
 46-49 expver
 experimentVersionNumber  
42 As for MARS labelling (eg set to zero, or ensemble forecast number if appropriate) 50 number number
43 As for MARS labelling (eg set to zero, or total number in ensembles if appropriate) 51 total total
  
44 Direction number 52 directionNumber directionNumber
  
45 Frequency number 53 frequencyNumber frequencyNumber
46 Total number of directions (Nd) 54 numberOfDirections numberOfDirections
  
47 Total number of frequencies (Nf) 55 numberOfFrequencies numberOfFrequencies
48 Integer scaling factor applied to directions in following list of direction definitions (4-byte integer) 56-59 directionScalingFactor directionScalingFactor
49 Integer scaling factor applied to frequencies in following list of frequency definitions (4-byte integer) 60-63 frequencyScalingFactor frequencyScalingFactor
- 
Flag to show inclusions in the header:
0 = system and method are not included
1 = system and method are included
2 = system, method, reference date, climate date (from)
    and climate date (to) are included
3 = all information in 2 leg information for variable 
    resolution systems are included
 64 flag flag
50+Nd+Nf System number (65535 = missing) 65-66 systemNumber systemNumber
51+Nd+Nf Method number (65535 = missing) 67-68 methodNumber methodNumber
52+Nd+Nf Reference date (YYYYMMDD) 69-72 referenceDate referenceDate
53+Nd+Nf Climate date - from (YYYYMMDD) 73-76 climateDateFrom climateDateFrom
54+Nd+Nf Climate date - to (YYYYMMDD) 77-80 climateDateTo climateDateTo
55+Nd+Nf Base time of this leg (YYYYMMDD) 81-84 legBaseDate legBaseDateo
56+Nd+Nf Base time of this leg (HHMM) 85-86 legBaseTime legBaseTime
57+Nd+Nf Leg number 87 legNumber legNumber
58+Nd+Nf 
	Ocean - Atmosphere coupling: 
	0 = unspecified
	1 = uncoupled
	2 = coupled
88 oceanAtmosphereCoupling oceanAtmosphereCoupling
- Spare (set to zero) 89-100 spareSetToZero3 spareSetToZero3
50->(49+Nd) List of Nd scaled directions (4-byte integers) 101->(100+Nd*4) scaledDirections scaledDirections
(50+Nd)->(49+Nd+Nf) List of Nf scaled frequencies (4-byte integers) (101+Nd*4)->(100+Nd*4+Nf*4) scaledFrequencies scaledFrequencies