Sub-seasonal 9+1 member hindcasts: 1989-2016: NN bias correction

Title Sub-seasonal 9+1 member hindcasts: 1989-2016: NN bias correction
Description The flow-dependent bias-correction experiment consists of sub-seasonal hindcasts performed with IFS cycle 48r1, in which model-error tendencies are estimated online using neural networks. Hindcasts are initialised on the 15th of each month from 1989 to 2016 and integrated forward for 32 days. For each start date, an ensemble of 10 members is generated, comprising one unperturbed control and nine perturbed members to sample initial-condition uncertainty. The model is run at TCo319 horizontal resolution with 137 vertical levels. The bias correction is implemented as an additive tendency applied to temperature and horizontal winds at each model time step. These tendencies are predicted by three neural networks (one each for zonal wind, meridional wind, and temperature) trained to diagnose 6-hourly mean model-error tendencies from the instantaneous model state. The networks follow the architecture of Espinoza et al. (2022) and use inputs including three-dimensional wind and temperature fields, surface pressure, solar geometry, and geographical location. This experiment is designed to assess the impact of a flow-dependent, state-aware representation of model error on sub-seasonal forecast skill.
DOI 10.21957/xtnt-2y33
Experiment ID ia5q
Experiment class ECMWF Research Department
Examples

Retrieve perturbed mebers from 15 September start hindcasts of T/U/V for years 1989 to 2016.

#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer

server = ECMWFDataServer()

server.retrieve({
    "class": "rd",
    "dataset": "research",
    "date": "2017-09-15",
    "expver": "ia5q",
    "hdate": "1989-09-15/1990-09-15/1991-09-15/1992-09-15/1993-09-15/1994-09-15/1995-09-15/1996-09-15/1997-09-15/1998-09-15/1999-09-15/2000-09-15/2001-09-15/2002-09-15/2003-09-15/2004-09-15/2005-09-15/2006-09-15/2007-09-15/2008-09-15/2009-09-15/2010-09-15/2011-09-15/2012-09-15/2013-09-15/2014-09-15/2015-09-15/2016-09-15",
    "levelist": "10/50/100/200/250/500/700/850/1000",
    "levtype": "pl",
    "number": "1/2/3/4/5/6/7/8/9",
    "param": "130.128/131/132",
    "step": "0/12/24/36/48/60/72/84/96/108/120/132/144/156/168/180/192/204/216/228/240/252/264/276/288/300/312/324/336/348/360/372/384/396/408/420/432/444/456/468/480/492/504/516/528/540/552/564/576/588/600/612/624/636/648/660/672/684/696/708/720/732/744/756/768",
    "stream": "enfh",
    "target": "output",
    "time": "00:00:00",
    "type": "pf"
})

Retrieve perturbed mebers from 15 April start hindcasts of 2m temperature for years 1989 to 2016.

#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer

server = ECMWFDataServer()

server.retrieve({
    "class": "rd",
    "dataset": "research",
    "date": "2017-04-15",
    "expver": "ia5q",
    "hdate": "1989-04-15/1990-04-15/1991-04-15/1992-04-15/1993-04-15/1994-04-15/1995-04-15/1996-04-15/1997-04-15/1998-04-15/1999-04-15/2000-04-15/2001-04-15/2002-04-15/2003-04-15/2004-04-15/2005-04-15/2006-04-15/2007-04-15/2008-04-15/2009-04-15/2010-04-15/2011-04-15/2012-04-15/2013-04-15/2014-04-15/2015-04-15/2016-04-15",
    "levtype": "sfc",
    "number": "1/2/3/4/5/6/7/8/9",
    "param": "167.128",
    "step": "0/12/24/36/48/60/72/84/96/108/120/132/144/156/168/180/192/204/216/228/240/252/264/276/288/300/312/324/336/348/360/372/384/396/408/420/432/444/456/468/480/492/504/516/528/540/552/564/576/588/600/612/624/636/648/660/672/684/696/708/720/732/744/756/768",
    "stream": "enfh",
    "target": "output",
    "time": "00:00:00",
    "type": "pf"
})