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Weather data methodology

Raw weather data from ECMWF and GFS

Hamza Aourach avatar
Written by Hamza Aourach
Updated this week

Models and acronyms

ECMWF (European Centre for Medium-Range Weather Forecasts)

Models are called EC.

  • Determinist model: one forecast (one trajectory) every 6h (00h, 06h, 12h and 18h) called EC OP

    • 00h and 12h run have 336h of forecast (~14 days)

    • 06h and 18h run have 120h of forecast (~5 days)

  • Determinist model: one forecast (one trajectory) every 6h (00h, 06h, 12h and 18h) called EC AIFS. All runs have 336h of forecast (~14 days)

  • Ensemble model: several forecasts (50 different trajectories) every 6h (00h, 06h, 12h and 18h) called EC ENS

    • 00h and 12h run have 336h of forecast (~14 days)

    • 06h and 18h run have 120h of forecast (~5 days)

  • Extended ensemble model: several forecasts (100 different trajectories) every day called EC 46. Forecast up to 46 days.

NOAA (National Oceanic and Atmospheric Administration)


Models are called GFS.

  • Determinist model: one forecast (one trajectory) every 6h (00h, 06h, 12h and 18h) called GFS OP. All runs forecast up to 15 days.

  • Ensemble model: several forecasts (30 different trajectories) every 6h (00h, 06h, 12h and 18h) called GFS ENS. All runs forecast up to 15 days.

Historical data

Actuals data are what is the closest to observations. To produce them we take the last forecasted values for each target hour. For example we take the first 12 hours of run 00h and first 12 hours of run 12h to have an entire day of actuals.

  • EC OP: We have data up to 2015-01-01 on European grid ("EU": "71/-15/35/45") with information every hour and a resolution of 0.1°.

  • GFS OP: We have data up to 2015-01-15 on European grid ("EU": "71/-15/35/45") with information every 3 hour and a resolution of 0.25°.

Weather parameters

There are 2 types of parameters : cumulated and instantaneous :

  • Instantaneous parameters: 2t, 2d, 100u, 100v, 10u, 10v, sp. This means that the hour indicated matches the exact time at which the parameter is calculated.

  • Cumulative parameters: tp, ssrd, ssr. Here, this means that the parameter is the accumulation since the beginning of the run (ECMWF) since the last modulo 6h (NOAA). The timestamp indicates the end of the accumulation period.

Long name

Kpler name

Unit

ECMWF name

NOAA name

2m temperature

2t

K

2t

2t

2m dew point

2d

K

2d

2d

10m u component of wind

10u

m/s

10u

10u

10m v component of wind

10v

m/s

10v

10v

100m u component of wind

100u

m/s

100u

u

100m v component of wind

100v

m/s

100v

v

total cloud cover

tcc

0-100 (EC OP / GFS), 0-1 (EC ENS /EC 46)

tcc

tcdc

0°C isotherm level

iso0

m (EC), gpm ≈ m (GFS)

deg0l

hg

surface pressure

sp

Pa

sp

sp (only available for GFS OP)

total precipitation

tp

mm (EC OP), m (EC ENS/EC 46), kg/m² = mm (GFS)

tp

apcp

Surface short-wave radiation downwards

ssrd

J/m² (EC), W/m² (GFS)

ssrd

dswrf

Surface net short-wave radiation

ssr

J/m² (EC), W/m² (GFS)

ssr

dlwrf

Surface run-off

sro

m (EC), mm (GFS)

sro

watr

Snowfall

sf

m (EC)

sf

Not availa ble

Snow depth

sd

m

sd

Not available

Note : Units reflect the most common format across models. Where differences exist (e.g., tcc or ssrd), they are noted directly in the Unit column.

FTP access

Parameters

Path: 1_Weather/Forecast/Parameters

  • EC_ENS: one folder per country then files sorted in year month folders then one file per forecast time

  • EC_AIFS : one folder per country then files sorted in year month folders then one file per forecast time

  • EC_ENS_EXTENDED: one folder per country then files sorted in year month day folders then one file per day of forecast

  • EC_OP: one folder per country then files sorted in year month day folders then one file per forecast time

  • GFS_ENS: one folder per country then files sorted in year month day folders then one file per forecast time

  • GFS_OP: one folder per country then files sorted in year month day folders then one file per forecast time

Temperatures

Path: 1_Weather/Forecast/Temperature

  • COR_E: One folder per country then files divided in year month folders then one file per run in the month

Longterm temperatures

Path: 1_Weather/Forecast/Longterm_Temperature

  • COR_E: One folder per country then one file per year that contains seasonal temperatures


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