Revision of the ATOVS/AMSU-A, AMSU-B, MHS channel selection for DA

Roger Randriamampianina and Benedikt Strajnar

Impact of the bias correctionImpact of the bias correction

How to perform the experimentsHow to perform the experiments

How to perform the experimentsHow to perform the experiments

- First of all one need to have precomputed first guesses

- Use these guesses to do series of passive analyses means do screening and minimization without 6h forecast

- Normally, one-month period is enough to check the functionality of the applied bias correction scheme.

- Before starting the series of passive analyses, it is recommended to change the blacklisting rules to have as much as possible active observation, or at least passive observations during the minimization. this means empty the file LISTE_LOC, and change the rules in the file mf_blacklist.b and recopile your pack to have new executable. NOTE: this executable is meant for the monitoring purpose ONLY and not suitable for any assimilation study !

How to check the necessary information for monitoringHow to check the necessary information for monitoring

-Example of odb request:

cat >myview.sql <<EOFSELECTobstype,statid, varno, press_rl, sensor, fov@atovs, an_depar, fg_depar, obsvalue, biasctrl, predictor[1]@atovs_predFROM hdr,desc,body,atovs,atovs_predWHERE ((varno /= 91 ) AND (an_depar is not NULL))EOF

Where:fg_depar- bias corrected O-Ban_depar- O-Abiasctrl - the applied bias correction To have the uncorrected O-B = fg_depar + biasctrl

One can plot the corrected and non-corrected departuresOne can plot the corrected and non-corrected departures

Dashed line: uncorrected departureBold: analysis biasSolid line: first-guess biasLower plot: number of active obs

24h update 6h update

Impact of the bias correction scheme

00 UTC 06 UTC 12 UTC 18 UTC

NOAA-16 -- 5-8(?), 9-12, 13(?)

-- 5-8(?), 9-11, 12(?), 13(?)

NOAA-18 5-11,

12(?),13(?)

-- 5-6(lp?), 7, 8(no), 9-12,

13(?)

--

NOAA-19 5(?), 6-7, 8(no), 9-12,

13(?)

-- 5-7, 8(no), 9-12, 13 (?)

--

METOP-2 -- 5(lp?), 6(no),7(no),8-12, 13(?)

5-8(lp?), 9-12,

13 (no)

5-8(no), 9-12,

13(?)

Results of the recent Hungarian monitoringResults of the recent Hungarian monitoring

AMSU-A

00 UTC 06 UTC 12 UTC 18 UTC

NOAA-16 -- 5(no),4(?), 3 -- 3-4, 5(no)

NOAA-18 5(no), 3-4 -- 3-4, 5(no) --

NOAA-19 5(no), 3-4 -- 3-4, 5(no) --

METOP-2 -- 3-5 3-4, 5(?) 3-4, 5(?)

AMSU-B / MHS

Results of the recent Hungarian monitoringResults of the recent Hungarian monitoring

Need longer period?

Bad channel

Bad channel

I would say no in this case