GRIB API Manual
Author: $Author: Enrico Fucile $
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## GRIB section 1, the product definition section

KSEC1 must be initialised when encoding; it is filled in by GRIBEX when decoding.

An INTEGER array.

When section 1 contains data for ECMWF local use, KSEC1 must be dimensioned accordingly, see ECMWF local GRIB usage definitions.

Contents of KSEC1
Element | Contents | GRIB API keys
--- | --- | ---
1 | Version number of code table 2 (see ECMWF local code table 2). | paramId
2 | Identification of centre (see WMO code table 0), 98 for ECMWF. | centre
3 | Generating process identification number, allocated by the originating centre. (255 is used at ECMWF as an indicator for dummy surface pressure fields). See ECMWF model identifiers. | generatingProcessIdentifier
4 | Grid definition. NNN catalogue number of grid used by the originating centre (See Volume B of WMO publication No.9). 255 for a non-catalogued grid, in which case the grid description follows in KSEC2. | gridType
5 | Flag showing whether sections 2 and 3 are present (see WMO code table 1):
      0, Sections 2 and 3 are omitted.
     64, Section 2 is omitted, Section 3 is included.
    128, Section 2 is included, Section 3 is omitted.
    192, Sections 2 and 3 are included.
| gridType bitmapPresent
6 | Parameter indicator (see WMO code table 2). | shortName paramId
7 | Type of level indicator (see WMO code table 3), or satellite identifier. Satellite usage is as defined by INPE/CPTEC and used by ECMWF pending final definition by WMO. | typeOfLevel
8 | Height, pressure, etc of level (see WMO code table 3). Single level or top of layer, or satellite spectral band. Satellite usage is as defined by INPE/CPTEC and used by ECMWF pending final definition by WMO. | level
9 | Height, pressure, etc of level (see WMO code table 3). Bottom of layer if element 7 indicates a layer. | typeOfLevel
10-14 | Reference time of data. Date and time of start of averaging or accumulation. | dataDate
10 | Year of century (YY). | dataDate
11 | Month (MM).
12 | Day (DD).
13 | Hour (HH). | dataTime
14 | Minute (MM).
15 | Time unit indicator (see WMO code table 4). | stepType = instant | avg | accum | max | min | diff | rms | sd | cov | ratio stepUnits = s (seconds) | m (minutes) | h (hours) | 3h | 6h | 12h | D (day) | M (month) | Y (year) | 10Y | 30Y | C (century) default value for stepUnits is "h" startStep, endStep stepRange (= "endStep" | "startStep-endStep" ) step
16 | P1 - Time period (number of time units) 0 for analyses or initialised analyses.
17 | P2 - Time period (number of time units). Or time interval between successive analyses, initialised analyses or forecasts undergoing averaging or accumulation. Otherwise set to zero.
18 | Time range indicator (see WMO code table 5).
19 | Number of products included in an average, when the time range indicates an average or accumulation. Otherwise set to zero.
20 | Number of products missing from an average, when the time range indicates an average or accumulation. Otherwise set to zero.
21 | Century of reference time of data (eg 20 for 1997). | date/1000-1
22 | Sub-centre identifier. | subCentre
23 | Decimal scale factor. | decimalScaleFactor decimalPrecision
24 | Flag field to indicate local use in Section 1:
    0       No local use in section 1.
    1       Local use in section 1.
| setLocalDefinition
25-36 | Reserved for WMO reserved fields. Set to 0. |
37 | ECMWF local GRIB use definition identifier. This number determines the contents of elements 38-nn. See ECMWF local GRIB usage definitions. Local definition numbers 192 to 255 inclusive will not be used for ECMWF local extensions. They are free for use by Member States. | class type stream expver ...

    Note:
      For year 2000, KSEC1(21) = 20 and KSEC1(10) = 100
      For year 2001, KSEC1(21) = 21 and KSEC1(10) = 1

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