Denis Blinov, G. Rivin, M. Nikitin, A. Bundel, A. Kirsanov, I. Rozinkina Data assimilation system based on nudging for COSMO-Ru7/So2 1COSMO GM Sibiu, 2

Denis Blinov,

G. Rivin, M. Nikitin, A. Bundel, A. Kirsanov, I. Rozinkina

Data assimilation system based on nudging for COSMO-Ru7/So2

1COSMO GM Sibiu, 2 - 5 Sept. 2013

Outline

• Initial conditions (IC) in operative Cosmo-Ru system• Errors IC • Data Assimilation System (DAS) based on nudging• Estimation experiments with DAS• Conclusions and outlook


Initial conditions in Cosmo-Ru• In the current operational scheme initial data are

prepared from the interpolated data GME (h=20 km);• Initial conditions are concluded

atmosphere fields (U, V, P, W, T, QV), surface fields (T_S, T_SNOW, T_ICE, H_ICE, T_SO,

W_SO)external parameters.


Errors of initial conditions• For the entire domain COSMO there are

significant errors in the field T_2m at the beginning of the forecast;

• It is supposed that errors in the initial data associated with all 3 types of fields: external parameters, atmospheric and surface fields.


Errors T_2m in COSMO-So2 (Adler-cluster)for winter 2011/2012 (left) and 2012/2013 (right)

for 00, 06, 12, 18 runs 5

RMSE

ME

Errors of initial conditions

DA system• Through the assimilation, we were trying to

reduce the errors in the atmospheric fields• DAS uses observations SYNOP, TEMP, SHIP,

BUOY, AIREP• The scheme Nudging in Cosmo is correcting

atmosphere fields T, PS, H, QV, U, V• On first step DAS is based on 6 hour cycle - Main

Run (MR)• On the next step DAS will included on continuous

cycle - Recalculate Run (RR)


Scheme of assimilation systemNamelist variable DA-M 07 RU 07 km DA-R RU02 DA-M RU02 RU 02 km

data_ini GME — 6 h DA-M 07 DA-R — 6h DA-R — 6h DA-M + 0h

data_bd GME — 6 h GME + 0 h RU07 — 6 h RU07 — 6 h RU07 — 6 h

hstop 6 78 6 6 24

number of runs 4 4 4 4 4

cut-off time 02:45:00 02:50:00 06:50 01:10 01:10:00

hnudgend 10 4 10 10 4

DA nudgcast DA nudgcast


The old(left) and new parallel(right) operational scheme COSMO-RU07 и COSMO-RU02

download GME 00UTC 06UTC 12UTC 18UTCstart 02:50 08:50 14:50 20:50end 03:25 09:10 15:25 21:10

Time work 00:35 00:20 00:35 00:20

00UTC 06UTC 12UTC 18UTC RU07 00UTC 06UTC 12UTC 18UTC

02:50 08:50 14:50 20:50 start 02:30 02:50 08:30 08:50 14:30 14:50 20:30 20:5003:30 09:10 15:30 21:10 end 02:50 03:30 08:50 09:10 14:50 15:30 20:50 21:1000:40 00:20 00:40 00:20 Time work 00:20 00:40 00:20 00:20 00:20 00:40 00:20 00:20

00UTC 06UTC 12UTC 18UTC RU02 00UTC 06UTC 12UTC 18UTC03:30 09:10 15:30 21:10 start 02:40 03:00 08:40 09:00 14:40 15:00 20:40 21:0005:10 10:50 17:10 22:50 end 03:00 05:00 09:00 11:00 15:00 17:00 21:00 23:0001:40 01:40 01:40 01:40 Time work 00:20 02:00 00:20 02:00 00:20 02:00 00:20 02:00

COSMO GM Sibiu, 2 - 5 Sept. 2013 8

Model grids and used observations grid OBSERVATIONS

domain modelT_2m

(TEMP)

wind_10m, pmsl, Td_2m

(TEMP + SYNOP)

ETR07 434.000 119 2700

CFO02 197.400 10 190

SFO02 197.400 6 170

VFO02 211.500 9 161

ENA13 500.000 295 4368

SIB14 90.000 78 1006

The number of grid points of the model ETR7 more than stations in ~1600 for the temperature and ~32000 for SFO2.Not enough of upper-air stations for successfully correcting temperature. You must use t_2m observation from SYNOP.


ExperimentsExperiments for COSMO-Ru7 with:

IC from DAS IC from GME

List verification stations:EPR887 – 887 stations on entire domain COSMO-Ru7EPR293 – 293 stations on entire domain COSMO-Ru7SFO – 145 stations on South Federal DistrictCFO – 220 stations on Central Federal District…

Period testing:February 2012July 2012December 2012


Mean error (ME) T_2m for EPR887 1-10 December 2012


Mean error T_2m for SFO 1-10 December 2012


Errors T_2m for initial time and forecast on 6 hours

• Found the understatement of the amplitude for all terms and for all seasons;

• The daytime temperature is underestimated, night overstated, morning and evening errors are minimal;

• On the chart of errors at the beginning of the forecast is observed local extremum. We believe that this effect is connected with interpolation from coarse grid (spinup);

• Very significant differences between the terms. On a 12-h forecast error temperature is minimal.


SFO00h_forecast 03h_forecast 06h_forecastref das ref das ref das

00UTC 0,79 0,95 0,92 0,73 0,37 0,1106UTC 0,35 0,19 -0,24 -0,41 -0,50 -0,6812UTC 0,02 -0,64 0,14 -0,18 0,41 0,0818UTC 0,45 0,23 0,47 0,24 0,76 0,44total 0,40 0,18 0,32 0,10 0,26 -0,01

Krasnaya Polyana00h_forecast 03h_forecast 06h_forecastref das ref das ref das

00UTC 2,53 1,70 1,98 1,74 2,44 2,1906UTC 3,25 2,88 0,37 -0,21 -1,92 -2,3712UTC -0,75 -1,45 -0,33 -0,50 1,07 0,8918UTC 2,82 1,37 0,87 1,53 1,55 1,14total 1,96 1,12 0,72 0,64 0,79 0,46

* Blue value indicate better results

Mean Error for T_2m

ref - experiment with initial conditions from GMEdas - experiment with initial conditions from Data Assimilation System



Experiments with DWD assimilation for COSMO-Ru domain, February 2012, EPR293

Experiments with DWD assimilation for COSMO-Ru domain, February 2012, SFO


ME

RMSE

Results testing DAS for field T_2m • Assimilation helps to improve the temperature

field during the early stages in the case of large errors in GME fields;

• When errors GME are minimal assimilation brings errors from 6-hour lead time. In some cases, it worsens the initial field - forecasts from 12 UTC;

• Mainly ME better on 0.3 degree for DAS;• It is necessary to correct/change the temperature

of the soil, snow, sea for Continuous Cycle.


ME, RMSE T_2m for EPR887 1-10 December 2012


ME, RMSE Td_2m for EPR887 1-10 December 2012


Mean error, RMSE PMSL for EPR887 1-10 December 2012


Mean error, RMSE wind speed 10m for EPR887 1-10 December 2012


Conclusions• Mainly effect of “spinup” at the beginning of the

forecast disappears;• Fields T_2m, Td_2m, PSML, Wind Speed 10m is

better with DAS in 0-3 hours forecast time;• When errors GME are minimal assimilation brings

errors from 6-hour lead time. In some cases, it worsens the initial field - for example forecasts from 12 UTC;

• It is necessary to correct/change the temperature of the soil, snow, sea for Continuous Cycle;

• It is necessary to use more observations.


Outlook• Correct surface field:

o T_Soil, T_air (correction module by Sapuntsova)o T_S via Flake

• Increase count of data in DAS: o feedback-fileoAMSoRadar data (Latent Heat Nudging)

• Testing continuous cycle for COSMO-So2 km



Experiments with module correction T_SO, T_air by Sapuntsova

Verification for 18 February 2012


Experiments with module correction T_SO, T_air by Sapuntsova

RMSE t_2m for February 2012

Thank you for attention!

Questions?Remark?


Documents

Denis Blinov, G. Rivin, M. Nikitin, A. Bundel, A. Kirsanov, I. Rozinkina Data assimilation system based on nudging for COSMO-Ru7/So2 1COSMO GM Sibiu, 2