Data assimilation works at Météo-France

presented by Claude Fischermaterial courtesy by F. Bouyssel, J.-F. Mahfouf, P. Chambon, C. Payan, V. Pourret, M. Martet, L. Berre, E. Arbogast

ALADIN/HIRLAM All Staff Meeting, Madrid, 1 April 2019

Météo-France

Outline of my talk

1. OBS and DA progress

2. DA (technically) works at MF …

OBS / DA progress

ALADIN/HIRLAM All Staff Meeting, 1 April 2019, Madrid

Operational assimilation of radars in AROME

● Operational assimilation of French radars (Météo France specific product) : 30 radars

● Operational implementation for systematic monitoring of other OPERA radars: 62 radars are included in the AROME-France domain

● Ongoing validation of OPERA radar data assimilation

● Definition of the OPTIMAL USE of OPERA radar data:– comparison between raw and filtered reflectivity for the

“no rain” identification,

– use of OPERA quality index.

– use of Doppler winds only when Nyquist velocity is higher than 30 m/s and correctly coded in the metadata.

=> Data availability in the OPERA DB-hub is varying ...

Use of OPERA radar data

Assimilation of OPERA radars in AROME (ongoing work)

● Validation against operational configuration:– RED: without other OPERA

radars

– BLACK: OPTIMAL USE of other OPERA radars

● Statistics of departures (Obs. assimilated):– Better fit of analysis of relative

humidity retrievals against all radars (French and other OPERA radars)

– Better fit of guess of radial wind against all radars (French and other OPERA radars)

Ongoing research on microwave data all-sky assimilation

Development of all-sky assimilation for passive microwave data using a 1D-Bayesian + 4D-Var framework

Duruisseau F, Chambon P, Wattrelot E, Barreyat M, Mahfouf J‐F. Assimilating cloudy and rainy microwave observations from SAPHIR on board Megha Tropiques within the ARPEGE global model. Q J R Meteorol Soc 2019;1–22. https://doi.org/10.1002/qj.3456

First instrument to be tested within the framework: SAPHIR onboard Megha-Tropiques

Relative difference of RMSE on Temperature forecasts errors in the Tropics with respect to ECMWF analysis significant at 99%

Impact on ARPEGE Temperature forecasts over a 4-month period (July to October 2018)

Up to 2%

improvement

Ongoing research on microwave data all-sky assimilation

Development of all-sky assimilation for passive microwave data using a 1D-Bayesian + 4D-Var frameworkDuruisseau F, Chambon P, Wattrelot E, Barreyat M, Mahfouf J‐F. Assimilating cloudy and rainy microwave observations from SAPHIR on board Megha Tropiques within the ARPEGE global model. Q J R Meteorol Soc 2019;1–22. https://doi.org/10.1002/qj.3456

First instrument to be tested within the framework: SAPHIR onboard Megha-Tropiques

Since Mid-November 2018, almost no SAPHIR data are available in Near Real-Time due to problems which are under investigation by ISRO and CNES

=> Therefore, these developments have now been adapted and work for the MHS sounders onboard MetOp-A, B, C and NOAA-19

Météo France AEOLUS HLOSW usePage 8

Monitoring and assimilation of AEOLUS HLOSW for an operational use

● Prepare our NWP SYSTEM to use HLOSW AEOLUS BUFR Data provided by ECMWF.Current pre-operational version of ARPEGE is ready to use AEOLUS data. First monitoring and assimilation experiments are in progress. Goal : to be ready as soon as data will be considered as valuable for our systems

● Fill our operational database with AEOLUS data as soon as they will be available on the GTS

● Monitoring Data to assess their quality. Monitoring of the first test data is in progress. Assess data according to their improvement.Goal : assess their quality to unbiase and blacklist if necessary

● Make assimilation experiment to assess AEOLUS HLOSW contribution and compute forecasting scoresOnce data quality will be considered good enough, assimilation and forecasting experiments will be done to compute impacts and scores on a period long enough to be representativeGoal : validate an operational use, second semester 2019

● Use AEOLUS in our operational system ASAPGoal : second semester 2019

Météo France AEOLUS HLOSW usePage 9

Monitoring sample after quality check

10

● Increase of increment resolution

Diagnosed length-scales● for zonal wind, near 850

hPa,● at 50 km resolution (T399)

L.Berre

Reduction of length-scales of background error correlations

Small scale structures better analysed

Diagnosed length-scales● for zonal wind, near 850

hPa,● at 40 km resolution (T499)

CY43T2 (current e-suite): resolution aspects for models, DA, EDA and EPS

New horizontal resolutions for global systems (deterministic, EDA, EPS)– ARPEGE: ~5km over France (Tl1798c2.2L105)– 4DVAR: 2 minimisations in Tl224c1L105 (90km) and Tl499c1L105 (40km)– EPS: 35 members (unchanged) at ~7.5km over France (~Tl1198c2.2L90) and four timesper day– EDA: 50 members in Tl499c1L105 (40km) => will sample B error correlations from 3*50 members instead of 6*25 currently (and sample variances from the specific 50 members)

- Other scientific and technical modifications for assimilation and observations ... in next slide

CY43T2 other DA/OBS contributions

● Tuning of sigma_b for humidity in ARPEGE-EDA● Variational bias correction for GNSS observations● Assimilation of more IASI channels over land● Inter-channels observation error correlation for IASI and CRIS● New channels assimilated for geostationnary CSR● Monitoring of new observations :

- GPSRO : GNOS/FY3-C, ROSA/MEGHA-T

- Microwave : AMSR2/GCOM-W1, MWRI/FY3-C, ATOVS, ATMS, MWHS-2 Flux DbNet, AMSUA et MHS on METOP-C, ATMS on NOAA20

- Scatterometer : OSCAT sur ScatSat-1- AMV wind : Goes-16, Goes-17, Metop-C- Doppler winds and radar reflectivities (European radars)

● New structure functions for T2m and H2m analysis

IFS/Arpège coord meeting CY47Page 13

2019 plans & beyond

■ 2019 e-suite (last e-suite before migration to new HPC if timing is early) :

― CY46T1

― Tuning of observation error stdev

― Assimilation of GNSS-RO from FY3-C, MWRI, AMSR-2

― Winds from AEOLUS, winds and radiances from GOES-16 and GOES-17

― Assimilation of NOAA-20 (CrIS and ATMS) and Metop-C (IASI, AMSU-A, MHS, ASCAT, GRAS) data

― Assimilation of scatterometer winds from ScatSat-1, CFOSAT and possibly HY-2B

― Assimilation of « all-sky » microwave radiances from MHS (in the Tropics)

― Arome aspects :► Monitoring and/or assimilation of OPERA radar data ; monitoring of Mode-S winds► Coupling EDA and 3D-VAR

■ Further outlook:

― 3D-EnVar for AROME (and 4D-EnVar later, Arome & Arpège)

― Towards the use of the Aeolus L2B processor at MF

― MODE-S with VarBC

― Satellite radiances: improved all-sky mw; new satellites/instruments according to space agency projections and data availability etc.

DA works at MF … CY46T1, OOPS use

ALADIN/HIRLAM All Staff Meeting, 1 April 2019, Madrid

IFS/Arpège coord meeting CY47Page 15

Validation of CY46T1 – DA component testing

■ Tremendous effort in order to validate DA with CY46T1:

― From June 2018 through February 2019; yet, today, a full Arpège 4D-VAR cycle has not yet been run

― Validated Arpège and Arome screening and minimization for all obs types

― Validated CANARI with less difficulties than CY43

― Thibaut Montmerle, Philippe Chambon, Camille Birman, Patrick Moll, Etienne Arbogast, Florian Suzat, Dominique Puech

■ DA component testing in prototype mode:

― At present, only in Etienne’s personal environment

― But used those tests during the debug stage of CY46T1

― Based on OOPS !

― Obs operator NL/TL/AD, Full-POS change of geometry, Arpège forecast, single obs low truncation 3D-VAR (T149)

Acabada la presentación, si hay alguna pregunta ... yo se las haré a los autores al volver a Toulouse.(gracias Daniel !)

claude.fischer@meteo.fr

http://www.umr-cnrm.fr/aladin/ - ALADIN website hosted at CNRM site.

Météo-France

Finished the presentation, if there is any question ... I will do it to the authors when returning to Toulouse.(thank you Google !)

claude.fischer@meteo.fr

http://www.umr-cnrm.fr/aladin/ - ALADIN website hosted at CNRM site.

Météo-France

CY43T2 scorecards