Federal Department of Home Affairs FDHA Federal Office of Meteorology and Climatology MeteoSwiss Conditional verification of all COSMO countries: first results COSMO General Meeting, September 2012, Lugano by the members of WG Verification

2 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Objectives of conditional verification Contribute to COSMO model development Improve the understanding of forecast errors Identify possible sources of errors in COSMO

3 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Feedback loop within COSMO COSMO operational application and development Conditional verification Physical aspects (atmosphere and soil) Data assimilation Predictability and EPS

4 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Common conditional verification results T2M for overcast conditions T2M for clear sky conditions Spring 2012, ME and RMSE for many COSMO modelsAutumn 2011, ME and RMSE for many COSMO models Cloud cover clearly stratifies the COSMO forecast error of T2M (no matter which diagnostic) Under observed clear sky conditions, the mean error has a pronounced daily cycle: All models underestimate daytime T2M and overestimate nighttime T2M Under observed overcast conditions, this behaviour is not observed

5 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Searching for clues… Additional stratification to look at cases with stable boundary layer → distinguish between dynamical and radiation dominated processes

COSMO-ME Conditional Verification T2m when observed TCC ≤ 25%

COSMO-ME Conditional Verification T2m when observed TCC ≤ 25% & wind speed ≤ 2 m/s

COSMO-7 Conditional Verification T2m when forecast TCC ≤ 25%

COSMO-7 Conditional Verification T2m when forecast TCC ≤ 25% & wind speed ≤ 2.5 m/s

10 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Searching for clues… Additional stratification to look at cases with stable boundary layer → distinguish between dynamical and radiation dominated processes → in calm wind conditions, the underestimation of the daily temperature amplitude is even more pronounced

11 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Nighttime overestimation

12 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Stations on the Swiss plateau T2M for clear sky conditions at stations with gph <800m

13 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Searching for clues… Additional stratification to look at cases with stable boundary layer → distinguish between dynamical and radiation dominated processes → in calm wind conditions, the underestimation of the daily temperature amplitude is even more pronounced → overestimated thermal mixing? Nighttime overestimation from insufficient radiative cooling? Daytime underestimation from underestimated sensible heat flux? Wrong soil moisture?

Td, 2mT with dry or wet soil conditions WG5 COSMO General Meeting, Lugano 2012 W_SO Water content of first soil layer(kg/m2) 1cm. Td: Higher error in dry soil and larger underestimation 2mT: Higher error in wet soil and larger understimation WinterSpringFall WinterSpringFall

15 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, T2M with fcst soil moisture condition ME, RMSE dry conditions ME, RMSE wet conditions ME, RMSE no conditions Similar systematic error properties as for cloud cover conditions, but phase slightly shifted and different data sample → new box opened…

16 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, TD2M with soil moisture condition ME, RMSE dry conditions ME, RMSE wet conditions ME, RMSE no conditions

17 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Conclusions Conditional verification provides us with tools for analysing complex COSMO model errors Use of intensive measurement sites will further help the analyses (e.g. for clear sky temperature error, measurements for sensible and latent fluxes, for temperature and dewpoint error, measurements for soil moisture) Suitable stratifications for precipitation still need to be identified (e.g. appropriate time integrations for CAPE, so far no success with weather classes) Tight interaction with WG3 and others

18 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, ADDITIONAL DISCUSSION POINTS For parallel session

19 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, List of conditional verifications I 2m temperature Comparison between observation based cloud cover conditions and forecast based cloud cover conditions 2 conditions: cloud cover and total cloud water column 2 conditions: cloud cover and wind speed Condition on soil type: 1:ice, 2:rock, 3:sand, 4:loam (incl. sandy & clay), 5:clay » bug on sample size reported Condition on soil temperature: T_SO>=0 ° C, T_SO<0 ° C Condition on soil water content: dry: W_SO 3.5m Condition on snow cover: W_SNOW>0mm, W_SNOW=0mm Condition on grid point height: gph>800m, gph<=800m Condition on GWTWS: annual

20 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, List of conditional verifications II 10m wind speed Condition on Z0: Z0 1 Condition on grid point height: gph>800m, gph<=800m Condition on GWTWS: annual Precipitation (6h) Condition on CAPE: comparison between CAPE_con or CAPE_mu Condition on GWTWS: annual Dewpoint Condition on soil moisture: dry: W_SO 3.5m

21 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, CV precipitation Ideas for distinction between convective (local) and large scale (synoptic) precip: CAPE, convective time scale after Keil (= CAPE/Precip) Appropriate time period to associate with precip? Pressure drop?

22 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Temperature and dewpoint Ideas about soil moisture errors? Weather type dependent verification: any success?

23 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, Weather type dependent verification any success? New insights?

24 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, PREC06 with weather classes: FBI0.2

25 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, PREC06 with weather classes: ETS0.2

26 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, FF10M with grid point height ME, RMSE all stations ME, RMSE gp height > 800m ME, RMSE gp height < 800m

27 Conditional Verification | COSMO-GM 2012, Lugano Vanessa Stauch, FF10M scatter plot Winter 2012