Ensemble- based observa/on impact es/mates using the NCEP/GFS

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1 PSU- UMD Daa Assimila/on Workshop 2012 Ensemble- based observa/on impac es/maes using he NCEP/GFS Yoichiro Oa (NCEP/EMC visi/ng from JMA) 12/13/2012 PSU- UMD DA Workshop

2 Observa/on impac es/ma/on (Kalnay e al 2012) Forecas error reduc/on is defined as Δe f g ( K 1) e ft δy Ce T o R f e gt Ce a ft f g ( HX ) X C( e + e ) 0 C: norm operaor, e f, e g : forecas error a from analysis and firs guess, M: angen linear model, K: Kalman gain, dy o : innova/ons, K: number of ensemble member, R: observa/on error convariance, X 0a : analysis ensemble perurba/ons, X f : forecas perurba/ons a, H: linealized observa/on operaor. g = 1 2 f g T f g 1 T f g ( e e ) C( e + e ) [ MKδy ] C( e + e ) Forecas error 2 M Analysis incremen - 6hr 0 Es/maes provide he rela/ve impacs of each observa/ons on he shor- range forecas accuracy. Any EnKF (no jus LETKF) can be used for he es/ma/ons. o Forecas error difference 12/13/2012 PSU- UMD DA Workshop

3 Experimenal se[ngs T254L64 80 member ensembles, 6 hourly cycle Serial EnSRF (Whiaker and Hamill 2002) 24 hour forecas error wih mois oal energy in global domain Period: 1/8/2012 ~ 2/7/2012 (ader one week spinup) All observa/on ypes (opera/onally assimilaed as of May 2012) excep precipia/on rae from TRMM/TMI are assimilaed (~3.3 million obs per 1 analysis) Localiza/on func/on for he impac es/mae is moved wih he horizonal wind (0.75 /mes) 12/13/2012 PSU- UMD DA Workshop

4 Lis of assimilaed observa/on ypes Type of daa Descripion Number (x1000) Radiosonde Radiosonde observaions (u, v, T, q and Ps) 55 Marine-Surface Surface u, v, T, q and Ps observaions from he buoys and ships 23 Land-Surface Ps observaions from land surface saions 54 Aircraf u, v, and T observaions from he aircrafs 173 Profiler_Wind u and v observaions from he wind profilers 12 NEXRAD_Wind u and v observaions from he NEXRAD (radar) 14 ASCAT_Wind u and v observaions from ASCAT scaeromeer over ocean 17 TCVial Pseudo surface pressure observaions a ropical cyclone sorm cener Saellie_Wind Amospheric Moion Vecors (u and v) from geosaionary saellies 96 Dropsonde Fligh-level reconnaissance and dropsonde (u, v, T and q) 0.2 PIBAL u and v observaions from pilo balloons 1.9 MODIS_Wind Amospheric Moion Vecors (u and v) from MODIS 36 WINDSAT_Wind u and v observaions from ASCAT scaeromeer over ocean (super observaion) 0.8 GPSRO GPS radio occulaion 95 Ozone Ozone rerievals from saellie radiances 14 Aqua_AIRS Saellie infrared hyper specral sounder radiances 630 AMSUA Saellie microwave sounder radiances (from 5 saellies) 586 HIRS Saellie infrared radiances (from 2 saellies) 119 IASI Saellie infrared hyper specral sounder radiances 1143 MHS Saellie microwave sounder radiances (from 3 saellies) 67 GOES GOES infrared sounder radiances (GOES13 and 15) 40 ATMS Saellie microwave sounder radiances (from Suomi-NPP) /13/2012 SEVIRI SEVIRI clear sky PSU- UMD radiances DA Workshop

5 Overall impacs 1) AMSUA 2) IASI 3) Aircrad 4) Radiosonde 5) AIRS All observa/on ypes have posi/ve impacs excep ozone rerievals. 12/13/2012 PSU- UMD DA Workshop

6 Impacs per 1 observa/on Impacs of TCVial and Dropsondes are exremely large. Impacs of conven/onal observa/on are large per 1 observa/on. These observa/ons are s/ll imporan. 12/13/2012 PSU- UMD DA Workshop

7 Impacs of each AIRS channels 12/13/2012 PSU- UMD DA Workshop

8 Impac of radiosonde per 1 profile 12/13/2012 PSU- UMD DA Workshop

9 Good sa/on VS Bad sa/on O- B sa/s/cs for sa/on 4270 (red) and 4220 (blue). Dashed line is bias and solid line is sandard devia/on. Observa/ons from 4270 seems no good as hose from /13/2012 PSU- UMD DA Workshop

10 Case sudy wih he local forecas failure Selec he local forecas failure cases (30 x 30 deg area) based on: 1) 24 hour forecas error is larger han 2 /mes of is /me average, and 2) 24 hour forecas error is larger han 1.2 /mes of he error of 30 hour forecas from he previous analysis. Compue observa/on impacs in local area and remove bad observa/ons. 12/13/2012 PSU- UMD DA Workshop

11 Local forecas failures Iniial Area Size Rae N Denied observaion Change 12 UTC 90S~60S GPSRO (80S~60S, 90E~120E) % JAN E~130E ASCAT (60S~50S, 100E~120E) AMSUA (ch4: 45N~75N, 160E~170W, ch5:40n~55n, 06 UTC 50N~80N E~180, NOAA15 ch6: 50N~75N, -11.4% JAN E ~ E~170W, ch7: 70N~80N, 130E~170E) 00 UTC JAN UTC JAN UTC FEB 2 18 UTC FEB 6 18 UTC FEB 6 30N~60N 30W~0 90S~60S 130E~160E Radiosonde wind (Valenia, Ireland), ASCAT (40N~47N, 20W~10W, 50N~55N, 35W~30W) AMSUA (ch5: 65S~50S, 90E~110E, 60S~50S, 120E~127E, ch6: 60S~45S, 110E~125E) -1.0% -2.2% 50N~80N 150W~120W IASI (35N~45N, 155W~150W) NEXRAD (55N~60N, 160W~135W) -5.5% 60N~90N 50E~80E 90S~60S 20W~10E MODIS_Wind (60N~90N, 30E~90E) -39.0% MODIS_Wind (80S~50S, 30W~0) -22.5% 12/13/2012 PSU- UMD DA Workshop

12 Observa/on denial experimen Z500 Denial of MODIS winds reduced he forecas error of he rough. Projec/on of he error change in he ensemble space gives good es/mae. e f par e f MKδy par X f ( a ) T 1 HX0 R δy par 12/13/2012 PSU- UMD DA Workshop

13 Summary and plans Observa/on impac es/ma/on using EnKF can give rela/ve impacs of each observing sysem, diagnosis of daa assimila/on sysem, monioring of observa/on qualiy, and help for inves/ga/on of shor- range forecas dropou case. There are possible applica/ons including advanced QC ool using impac es/maes and impac verified agains observa/ons. 12/13/2012 PSU- UMD DA Workshop