1. Context.The concept of "nominal" start date in lagged start ensembles
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Due to a number of reasons, members from ensembles using the "lagged start" approach are bundled together at C3S and labelled with a "nominal" start date (see details here).
The C3S seasonal forecast datasets are based on GRIB files stored at ECMWF MARS archive where that "nominal" start date is used to index the monthly data (monthly statistics and monthly post-processed products like anomalies). Hence, the details about the original initialization date could get lost in those files. Nonetheless, the data at daily and sub-daily time frequencies is always encoded with the real initialization date, as it can be seen in the example below:
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| Code Block |
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| language | bash |
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| theme | RDark |
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| title | GRIB file contents |
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> grib_ls -p origin,type,shortName,number,indexingDate,indexingTime,dataDate,dataTime,indexingDate,indexingTime,step,fcmonth,verifyingMonth c3s_seas_ukmo199312_t2m.grib
c3s_seas_ukmo199312_t2m.grib
origin type shortName number dataDateindexingDate indexingTime dataTimedataDate indexingDatedataTime indexingTime step fcmonth verifyingMonth
egrr fcmean 2t 0 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 1 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 2 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 3 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 4 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 5 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 6 not_found 19931201 not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 7 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 8 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 9 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 10 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 11 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 12 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 13 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 14 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 15 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 16 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 17 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 18 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 19 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 20 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 21 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 22 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 23 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 24 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 25 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 26 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 27 19931201not_found not_found 0 19931201 0 not_found not_found 744 1 199312
egrr fcmean 2t 0 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 1 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 2 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 3 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 4 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 5 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 6 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 7 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 8 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 9 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 10 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 11 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 12 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 13 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 14 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 15 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 16 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 17 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 18 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 19 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 20 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 21 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 22 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 23 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 24 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 25 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr fcmean 2t 26 19931201not_found not_found 0 19931201 0 not_found not_found 1488 2 199401
egrr
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Example 2: NCEP hindcast data for December 1993 (localDefinitionNumber=12)
| Code Block |
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| language | py |
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| title | CDS API script |
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import cdsapi
c = cdsapi.Client()
c.retrieve(
fcmean 'seasonal-monthly-single-levels',
{
2t 'format': 'grib',
27 'originating_centre': 'ncep',
'system': '2',
not_found 'variable': '2m_temperature',
not_found 19931201 'product_type': 'monthly_mean',
0 'year': '1993',
'month': '12',
1488 'leadtime_month': [ '1', '2', ],
2 },
'c3s_seas_ukmo199312_t2m.grib')
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| Code Block |
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| language | bash |
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| title | GRIB file contents |
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> grib_ls -p origin,type,shortName,number,dataDate,dataTime,indexingDate,indexingTime,step,fcmonth,verifyingMonth c3s_seas_ncep199312_t2m.grib
c3s_seas_ncep199312_t2m.grib
origin 199401 type |
Example 2: NCEP hindcast data for December 1993 (localDefinitionNumber=12)
| Code Block |
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| language | py |
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| theme | RDark |
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| title | CDS API script |
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import cdsapi
c = cdsapi.Client()
c.retrieve(
shortName'seasonal-monthly-single-levels',
{
number 'format': 'grib',
dataDate 'originating_centre': 'ncep',
dataTime 'system': '2',
indexingDate indexingTime 'variable': '2m_temperature',
step 'product_type': 'monthly_mean',
fcmonth 'year': '1993',
verifyingMonth
kwbc 'month': '12',
fcmean 'leadtime_month': [ '1', '2', ],
},
'c3s_seas_ukmo199312_t2m.grib')
|
| Code Block |
|---|
| language | bash |
|---|
| theme | RDark |
|---|
| title | GRIB file contents |
|---|
|
> grib_ls -p origin,type,shortName,number,indexingDate,indexingTime,dataDate,dataTime,step,fcmonth,verifyingMonth c3s_seas_ncep199312_t2m.grib
c3s_seas_ncep199312_t2m.grib
origin2t 0 type shortName 19931127 number 0 indexingDate indexingTime 19931201dataDate 0dataTime step 840 fcmonth 1 199312 verifyingMonth
kwbc fcmean 2t 10 1993112719931201 60 1993120119931127 0 840 1 199312
kwbc fcmean 2t 1 2 19931201 19931127 0 12 1993120119931127 06 840 1 199312
kwbc fcmean 2t 32 1993112719931201 180 19931201 19931127 0 12 840 1 199312
kwbc fcmean 2t 43 1993112219931201 0 1993120119931127 018 960840 1 199312
kwbc fcmean 2t 54 1993112219931201 60 1993120119931122 0 960 1 199312
kwbc fcmean 2t 5 6 19931201 19931122 0 12 1993120119931122 06 960 1 199312
kwbc fcmean 2t 76 1993112219931201 180 19931201 19931122 0 12 960 1 199312
kwbc fcmean 2t 87 1993111719931201 0 1993120119931122 018 960 1080 1 199312
kwbc fcmean 2t 98 1993111719931201 60 1993120119931117 0 1080 1 199312
kwbc fcmean 2t 9 10 19931201 19931117 0 12 1993120119931117 06 1080 1 199312
kwbc fcmean 2t 1110 1993111719931201 180 19931201 19931117 0 12 1080 1 199312
kwbc fcmean 2t 1211 1993111219931201 0 1993120119931117 018 12001080 1 199312
kwbc fcmean 2t 1312 1993111219931201 60 1993120119931112 0 1200 1 199312
kwbc fcmean 2t 13 14 19931201 19931112 0 12 1993120119931112 06 1200 1 199312
kwbc fcmean 2t 1514 1993111219931201 180 19931201 19931112 0 12 1200 1 199312
kwbc fcmean 2t 1615 1993110719931201 0 1993120119931112 018 13201200 1 199312
kwbc fcmean 2t 1716 1993110719931201 60 1993120119931107 0 1320 1 199312
kwbc fcmean 2t 17 18 19931201 19931107 0 12 1993120119931107 06 1320 1 199312
kwbc fcmean 2t 1918 1993110719931201 180 19931201 19931107 0 12 1320 1 199312
kwbc fcmean 2t 2019 1993110219931201 0 1993120119931107 018 14401320 1 199312
kwbc fcmean 2t 2120 1993110219931201 60 1993120119931102 0 1440 1 199312
kwbc fcmean 2t 21 22 19931201 19931102 0 12 1993120119931102 06 1440 1 199312
kwbc fcmean 2t 2322 1993110219931201 180 19931201 19931102 0 12 1440 1 199312
kwbc fcmean 2t 023 1993112719931201 0 1993120119931102 018 1440 1584 1 2 199401199312
kwbc fcmean 2t 10 1993112719931201 60 1993120119931127 0 1584 2 199401
kwbc fcmean 2t 1 2 19931201 19931127 0 12 1993120119931127 06 1584 2 199401
kwbc fcmean 2t 32 1993112719931201 180 19931201 19931127 0 12 1584 2 199401
kwbc fcmean 2t 43 1993112219931201 0 1993120119931127 018 17041584 2 199401
kwbc fcmean 2t 54 1993112219931201 60 1993120119931122 0 1704 2 199401
kwbc fcmean 2t 5 6 19931201 19931122 0 12 1993120119931122 06 1704 2 199401
kwbc fcmean 2t 76 1993112219931201 180 19931201 19931122 0 12 1704 2 199401
kwbc fcmean 2t 87 1993111719931201 0 1993120119931122 018 18241704 2 199401
kwbc fcmean 2t 98 1993111719931201 60 1993120119931117 0 1824 2 199401
kwbc fcmean 2t 9 10 19931201 19931117 0 12 1993120119931117 06 1824 2 199401
kwbc fcmean 2t 1110 1993111719931201 180 19931201 19931117 0 12 1824 2 199401
kwbc fcmean 2t 1211 1993111219931201 0 1993120119931117 018 19441824 2 199401
kwbc fcmean 2t 1312 1993111219931201 60 1993120119931112 0 1944 2 199401
kwbc fcmean 2t 13 14 19931201 19931112 0 12 1993120119931112 06 1944 2 199401
kwbc fcmean 2t 1514 1993111219931201 180 19931201 19931112 0 12 1944 2 199401
kwbc fcmean 2t 1615 1993110719931201 0 1993120119931112 018 20641944 2 199401
kwbc fcmean 2t 1716 1993110719931201 60 1993120119931107 0 2064 2 199401
kwbc fcmean 2t 17 18 19931201 19931107 0 12 1993120119931107 06 2064 2 199401
kwbc fcmean 2t 1918 1993110719931201 180 19931201 19931107 0 12 2064 2 199401
kwbc fcmean 2t 2019 1993110219931201 0 1993120119931107 018 21842064 2 199401
kwbc fcmean 2t 2120 1993110219931201 60 1993120119931102 0 2184 2 199401
kwbc fcmean 2t 21 22 19931201 19931102 0 12 1993120119931102 06 2184 2 199401
kwbc fcmean 2t 2322 1993110219931201 180 19931201 19931102 0 12 2184 2 199401
kwbc fcmean 2t 23 19931201 0 19931102 18 2184 2 199401
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