Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept Status Report PP KENDA Christoph Schraff Deutscher Wetterdienst, Offenbach, Germany Contributions / input by: Hendrik Reich, Andreas Rhodin, Annika Schomburg, Ulrich Blahak, Yuefei Zeng, Roland Potthast Yuefei Zeng, Klaus Stephan, Africa Perianez, Michael Bender (DWD) Chiara Marsigli, Tiziana Paccagnella (ARPA-SIM) Lucio Torrisi (CNMCA) Daniel Leuenberger, Luca Weber (MeteoSwiss) Mikhail Tsyrulnikov, Igor Mamay (HMC) Amalia Iriza (NMA) general overview assimilation of SEVIRI-derived cloud top height in LETKF

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept LETKF: implementation experiment chain in NUMEX set up GME LETKF experiment for June 2011 lateral BC by direct interpolation from 60 km to 2.8 km KENDA: –1-hourly cycling, radiosonde, aircraft, wind profiler, synop –40 ensemble members, basic set-up (only adaptive cov. infl.) –assimilation only, optimally takes  1 real day for 1 day of assimilation, but in fact: ~ 1 – 4 real months for 1 week of assimilation ! (without forecasts !!)  only 3 experiments so far

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept LETKF: implementation other work: adaptive estimation of observation errors in observation space multi-step analysis implemented compare KENDA ensemble forecasts with COSMO-DE-EPS (8 days) at MCH / ARPA-SIM : studies on influence of different lateral BC (resolution gap) at MCH: compare determinstic LETKF analysis with nudging ana. (7 days) Hendrik: new flexible stand-alone scripts to run LETKF experiments without using NUMEX / archive  very limited disk space  1 real day for 1 day of LETKF assimilation to do: implement evaluation / verification tools in script suite may become very suitable tool for users outside DWD (academia)

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept Impact of lateral BC resolution Marsigli, Paccagnella, Montani: Test impact of lateral BC resolution for convection-permitting EPS 8 cases from Hymex SOP: 6 Sept. – 5 Nov COSMO-H2-EPS set-up (‘H2-CLEPS’): 2.8 km, 50 levels 10 members IC + BC COSMO-LEPS, res. 7 km run at 12 UTC 36h forecast range exp. ‘H2-IFS’: direct nesting IC and BC from IFS-EPS res: 0.25 °

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept mean difference between pairs of ensemble members < spread < rmse (i.e. e.g. betw. Member 1 of H2-CLEPS and Member 1 of H2-IFS) 1 exceptional case spin-up noise dies within 30 min impact on precip scores negligible 500 hPa geopotential Impact of lateral BC resolution

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept LETKF: implementation of verification production of ‘full’ NetCDF feedback files done:make clean interfaces to observation operators in COSMO … … integrate them into 3DVAR package to be done (this autumn !) : extend flow control (read correct Grib files etc.) ensemble-related diagnostic + verification tool, using feedback files : (Iriza, NMA) – ensemble scores implemented, further testing required

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept testing KENDA at MCH, ARPA-SIM OSSE –temperature inversion in Po Valley: assimilate synthetic TEMP –(semi-)idealised: horizontally homogeneous case; daily cycle of Alpine pumping  develop OSSE capability  COSMO reading feedback files implemented no PhD project on idealised OSSE to investigate convective-scale issues

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept accounting for model error stochastic perturbation of physics tendencies (SPPT) (Torrisi) –perturbation of moist turbulence tendencies implemented –implemented in (private) V4_26 –tests (LETKF for COSMO-ME): drying effect on precip –further tests in MCH / ARPA-SIM Pattern Generator (for random fields with prescribed correlation scales) (Tsyrulnikov et al.)

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept high-resolution obs radar –obs operators finished –radial winds v r in LETKF: Yuefei Zeng (DWD, until summer 2014)  monitoring of 3d volumn data (statistics of observation increments) : large scatter, data quality problems  need to test thinning / superobbing strategies  3-hour assimilation with 1-hrly cycle done (different localization radii) –v r + reflectivity Z in LETKF: Theresa Bick (HErZ-I Bonn, until end 2014 at least) GPS slant path delay –obs operator (incl. TL / adjoint) implemented in 3DVar, approximations tested –implementation in COSMO should start soon

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept high-resolution obs (SEVIRI-based, radiosonde-corrected) cloud top height : see next slides (Schomburg) new task: Raman lidar and microwave radiometer T-, q- profiles (Haefele, MCH) direct assimilation of SEVIRI radiances (window channels for cloud info) (Perianez) –technically implemented (obs operator (RTTOV), reading / writing) –work on monitoring / assimilation start in Nov.

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept avoid too strong penalizing of members with high humidity but no cloud avoid strong penalizing of members which are dry at CTH obs but have a cloud or even only high humidity close to CTH obs  search in a vertical range  h max around CTH obs for a ‘best fitting’ model level k, i.e. with minimum ‘distance’ d: Z [km] Cloud top RH [%] CTH obs function of relative humidity height of model level k = 1 use f (RH obs =1) – f (RH k ) and CTH obs – h k as 2 separate obs increments in LETKF if cloud observed with cloud top height CTH obs, what is the appropriate type of obs increment ? (if above a layer with cloud fraction > 70 %, then choose top of that layer) use of (SEVIRI-based) cloud top height (CTH) ‘observations’ in LETKF: method

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept Z [km] „no cloud“ CLC assimilate cloud fraction CLC = 0 separately for high, medium, low clouds model equivalent: maximum CLC within vertical range type of obs increment, if no cloud observed ? Z [km] - no data - „no cloud“ Cloud top model profile use of (SEVIRI-based) cloud top height (CTH) ‘observations’ in LETKF: method

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept relative humidity cloud cover cloud water cloud ice observed cloud top 3 lines on one colour indicate ensemble mean and mean +/- spread 1 analysis step, 17 Nov. 2011, 6 UTC (wintertime low stratus) vertical profiles example: missed cloud event CTH single-observation experiments

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept observed cloud top observation location example: missed cloud event specific water content [g/kg] relative humidity [%] cross section of analysis increments for ensemble mean CTH single-observation experiments

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept CTH single-observation experiments temperature profile (mean +/- spread) example: missed cloud event first guess analysis 1000 m 2000 m 3000 m observed cloud top  LETKF introduces inversion due to RH(CTH)  T cross correlations in first guess ensemble perturbations 270 K280 K290 K270 K280 K290 K

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept relative humidity cloud cover cloud water cloud ice observed cloud top 3 lines on one colour indicate ensemble mean and mean +/- spread vertical profiles example: false alarm cloud  assimilated quantity: cloud fraction (= 0) CTH single-observation experiments

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept high cloud cover [octas] FG ANA  LETKF decreases erroneous cloud cover despite very non-Gaussian distributions mid-level cloud cover [octas] FG ANA example: false alarm cloud  assimilated quantity: cloud fraction (= 0) FG ANA low cloud cover [octas] cover CTH single-observation experiments observation increments - histogram over ensemble members

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept example: false alarm cloud  assimilated quantity: cloud fraction (= 0) FG ANA low cloud cover [octas]mid-level cloud cover [octas]high cloud cover [octas] cover CTH single-observation experiments observation increments - histogram over ensemble members FG ANA FG ANA  LETKF decreases erroneous cloud cover despite very non-Gaussian distributions

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept :00 UTC 6:00 UTC 12:00 UTC 17:00 UTC cycled assimilation of dense CTH obs observed cloud top height (CTH) 1-hourly cycle over 21 hours, 13 Nov., 21 UTC – 14 Nov. 2011, 18 UTC (wintertime low stratus)

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept :00 UTC 6:00 UTC 12:00 UTC 17:00 UTC cycled assimilation of dense CTH obs : LETKF setup thinning: use obs at every 5 th grid pt. adaptive covariance inflation, adaptive localisation scale (  ~ 35 km) Observation error variances : relative humidity = 10 % cloud cover = 3.2 octa cloud top height [m] : 

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept cycled assimilation of dense CTH obs FG ANA RMSE bias  analysis error smaller than first guess (FG) errors time series of errors for deterministic run, averaged over cloudy obs locations ‘CTH’  CTH obs  height k ‘RH’  1 - RH k (k : ‘best fitting model level’) ‘RH at obslev’ (i.e. at observed CTH)

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept cycled assimilation of dense CTH obs RMSE spread time series of errors of ensemble mean / spread of ensemble averaged over cloudy obs locations averaged over cloud-free obs locations  underdispersive, but no trend for reduction of spread

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept RMSE bias time series of first guess errors (det. run), averaged over cloudy obs locations cycled assimilation of dense CTH obs no assimilation with cloud assimilation  CTH assimilation : hardly reduces height error of selected level k reduces RH (1-hour forecast) errors ‘RH at obslev’

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept cycled assimilation of dense CTH obs RH at obslev RMSE bias no assimilation with cloud assimilation  CTH assimilation : reduces RH errors related to low + mid-level cloud time series of first guess errors, averaged over cloudy obs locations

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept cycled assimilation of dense CTH obs time series of first guess errors, averaged over cloud-free obs locations (errors are due to false alarm cloud) mean square error of cloud fraction [octas]

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept low clouds mid-level clouds high clouds cycled assimilation of dense CTH obs ‘false alarm’ cloud cover (after 6 hrs cycling) with cloud assimilation no assimilation

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept time series of first guess errors, averaged over cloudy obs locations cycled assimilation of dense CTH obs assimilation of conventional obs only assimilation of conventional + cloud obs localization scale: adaptive / 20 km RMSE bias  CTH assimilation : reduces RH (1-hour forecast) errors even slightly reduces height error of selected level k

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept no assimilation RH at obslev cycled assimilation of dense CTH obs first guess fields after 20 hours of cycling (cloudy obs locations) CTH obs cloud assimilation conventional onlyconventional + cloud

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept PBPV – 03/ No assim no assimilation cloud assimilation conventional onlyconventional + cloud total cloud cover of first guess fields after 20 hours of cycling CTH obs satellite obs cycled assimilation of dense CTH obs

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept cycled assimilation of dense CTH obs time series of first guess errors, averaged over cloud-free obs locations (errors are due to false alarm cloud) mean square error of cloud fraction [octas]  error reduced (almost) everywhere

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept low clouds mid-level clouds high clouds cycled assimilation of dense CTH obs ‘false alarm’ cloud cover (after 20 hrs cycling) conventional + cloud conventional obs only

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept Summary assimilation of CTH by LETKF reduces errors of first guess (1-h forecast) tends to introduce humidity / cloud where it should (+ temperature inversion) tends to reduce ‘false-alarm’ clouds despite non-Gaussian pdf’s no sign of filter collapse (decrease of spread) next: evaluate forecast impact use of (SEVIRI-based) cloud top height (CTH) ‘observations’ in LETKF

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept with cloud assimilation no assimilation ‘ CTH‘ OBS-FG RH RH at obslev cycled assimilation of dense CTH obs first guess fields after 20 hours of cycling (cloudy obs locations) CTH obs

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept Low cloud cover (COSMO) PBPV – 03/ :00 UTC Cloud assim conv Cloud +conv No assim

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept RMSE and bias for different heights separately: Cloud assim. vs. no assim. v

Status of PP KENDA COSMO General Meeting, Sibiu, 2 – 5 Sept LETKF: validation of forecasts from KENDA COSMO-DE EPS EPS on KENDA intermediate combined