COSMO-SREPS Priority Project

C. MarsigliARPA-SIM - HydroMeteorological Service of Emilia-

Romagna, Bologna, Italy

limited-area model error: schemes, parameters,

surface forcings

COSMO-SREPS methodology

i.c. and b.c. perturbations -> INM multi-model multi-boundary (SREPS)

model perturbations -> parameter perturbation (fixed value throughout the integration to test the impact of the different parameter perturbations)

LAM ensemble

driving model erroranalysis

error at the global model

scale

larger scale errors

smaller scale errors

System applications

COSMO Priority Project -> Short-Range Ensemble

1D-Var DA of satellite data to provide retrievals to be nudged within 7km COSMO-I7: test of the use of COSMO-SREPS to estimate a flow-dependent B matrix

COSMO-SREPS provides boundary conditions for the ensemble system at 2.8 km under development at DWD (COSMO-DE-EPS)

Involved COSMO people

Marsigli, Montani, Paccagnella (ARPA-SIM): 1.5 FTE

Flora Gofa, Petroula Louka (HNMS): verification, 0.5 FTE

Collaboration:

Susanne Theis, Christoph Gebhardt (DWD): EELMK

Uli Schaettler (DWD): COSMO model code

Task 0. Preliminary actions for the system set-up: completed.

Task 1. Definition of the methodologies to perturb model trajectories: completed

Task 2. Definition of the methodologies to perturb initial conditions: suspended

Task 3. System set-up: completed (set-up for the JJASON 2007 period during the MAP D-PHASE DOP)

Task 4. Test on case studies: on-going (21 runs in autumn 2006 done, analysis on-going)

Task 5. Test on a regular basis: on-going (running on the JJASON 2007 period during the MAP D-PHASE DOP)

Task 6. Verification: on-going

System set-up

16 COSMO runs 10 km

hor. res.40 vertical

levels

COSMO at 25 km on IFS

IFS – ECMWF globalb

y I

NM

S

pain

COSMO at 25 km on GME

GME – DWD global

COSMO at 25 km on UM

UM – UKMO global

COSMO at 25 km on NCEP

AVN – NCEP global

P1: control (ope)

P2: conv. scheme (KF)

P3: tur_len=1000

P4: pat_len=10000

intra-group distance14 days (00UTC runs)

2mT

whole domain

Daily precipitation ROC area

Northern Italy + Switzerland observations

Average over 0.5 x 0.5 deg boxes - +42h fc range

Daily precipitation ROC area

Northern Italy + Switzerland observations

Average over 0.5 x 0.5 deg boxes - +66h fc range

Relationship between error and spread

12UTC runs

Northern Italy observations

Nearest grid point

ensemble mean 2m Temperature nearest grid point

0

1

2

3

4

5

6

7

6 12 18 24 30 36 42 48 54 60 66 72

Forecast time

RM

SE

-6

-4

-2

0

2

4

6

6 12 18 24 30 36 42 48 54 60 66 72

Forecast time

BIA

S

Ensemble member verificationPrecipitation – 0-0.1 mm / 6h

6-hr Accumulative precipitation(interpolation of 9 grid points)

0.8

0.82

0.84

0.86

0.88

0.9

0.92

0.94

0.96

0.98

1

6 12 18 24 30 36 42 48 54 60 66 72

Forecast time

PO

D

YESObs

HitsPOD

IFS

GME

UKMO

NCEP

6-hr Accumulative precipitation(interpolation of 9 grid points)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

6 12 18 24 30 36 42 48 54 60 66 72

Forecast time

FA

R

YESFc

alarmsFalseFAR

Ensemble member verificationPrecipitation – 0-0.1 mm / 6h

6-hr Accumulative precipitation(interpolation of 9 grid points)

0.8

0.82

0.84

0.86

0.88

0.9

0.92

0.94

0.96

0.98

1

6 12 18 24 30 36 42 48 54 60 66 72

Forecast time

PO

D

Tiedtke, pat_len500

Kain-Fritsch, pat_len500

Tiedtke, tur_len1000, pat_len500

Tiedtke, pat_len10000

6-hr Accumulative precipitation(interpolation of 9 grid points)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

6 12 18 24 30 36 42 48 54 60 66 72

Forecast time

FA

R

Deterministic scores – ave 0.5 x 0.5 IT+SV

1mm/24h

5mm/24h

10mm/24h

12 UTC

Deterministic scores – ave 0.5 x 0.5 IT+SV

1mm/24h

5mm/24h

10mm/24h

12 UTC

Conclusions

ic and bc perturbations contribute to the spread for an amount approximately double with respect to the parameter perturbations, statistically over the whole domain and the whole period in terms of 2mT. Locally (in space and time) the situation can be quite different

the selected parameters produce a detectable spread among members with the same father

rms error is grater than spread for all the events but the correlation is good

different fathers contribute differently to the skill, for different parameters this is less clear

On-going activities run of COSMO-SREPS with model perturbations for the DOP MAP D-PHASE (6 months, June-November 2007) :

statistical analysis of the system

comparison with the other available mesoscale ensemble systems

verification - system analysis (HNMS)

provide b.c. for DWD ensemble tests

test a flow-dependent B-matrix for 1D-Var of satellite data

test of different parameters (16 runs using only the IFS initial and boundary conditions)

Test of parameter perturbations (same father)

16 LM runs at 10 km

P1: control (ope)

P2: conv. scheme (KF)

P3: parameter 1

P4: parameter 2

P5: …

IFS – ECMWF global

Fine

run nr. parameter name parameter description range default used1 ctrl ope2 lconv convection scheme T or KF T KF3 tur_len maximal turbulent length scale [100,1000] m 500 1504 tur_len maximal turbulent length scale [100,1000] m 500 10005 pat_len length scale of thermal surface patterns [0,10000] m 500 100006 rat_sea ratio of laminar scaling factors for heat over [1,100] 20 17 rat_sea ratio of laminar scaling factors for heat over [1,100] 20 608 qc0 cloud water threshold for autoconversion [0.,0.001] 0 0.0019101112

13 c_lndsurface area density of the roughness elements over land [1,10] 2 1

14 c_lndsurface area density of the roughness elements over land [1,10] 2 10

15 rlam_heat scaling factor of the laminar layer depth [0.1,10] 1 0.116 rlam_heat scaling factor of the laminar layer depth [0.1,10] 1 10