1. Head, Meteorological Operations Section, ECMWF
David Richardson
Head, Meteorological Operations Section, ECMWF
GIFS-TIGGE WG February 2010

2. ECMWF EPS – changes
Revised stochastic physics September 2009 (cycle 35r3)
Improved T850 probabilities, especially in tropics
Resolution increase January 2010 (cycle 36r1)
62 levels, 32km (T639) to day 10, then 65km (T319) to day 15
Initial perturbations (spring 2010): replace evolved SVs with Ensemble of Data Assimilation
Better-tuned spread in first 48 hours over the extra-tropics
Substantial increase in spread in tropics, improving under- dispersion
GIFS-TIGGE WG February 2010

3. Stochastically Perturbed Parametrization Tendencies (SPPT)
09/12/2018
Stochastically Perturbed Parametrization Tendencies (SPPT)
Buizza et al 1999
ΔXp= ( 1+rX) ΔXc
Revised scheme (35r3)
ΔXp= ( 1+μr) ΔXc
Random numbers rX constant in 10o by 10o lat/lon boxes, and for 6 model time steps (3h in T399)
Random pattern r based on multiple independent AR(1) processes in spectral space, with de-correlation scales 500 km and 6 h
Uniform distribution between −0.5 and +0.5
Gaussian distribution with stdev 0.5 (limited to ±3stdev)
Independent random numbers rX for X=T, q, u, v
Same random number r
for X=T, q, u, v
Perturbations in entire column
No perturbations in lowest 300 m and above 50 hPa (0≤ μ ≤1)
Xc unperturbed tendency, Xp perturbed tendency
Tapering μ introduced to avoid excessive perturbations amplitudes that are numerically unstable in boundary layer
and to avoid large perturbations of mostly radiative tendencies in the stratosphere that are believed to be less uncertain than the net physics tendency in the troposphere.
GIFS-TIGGE WG February 2010

4. EPS grid
GIFS-TIGGE WG February 2010

5. Registered TIGGE users at ECMWF
687
GIFS-TIGGE WG February 2010

6. Active TIGGE users at ECMWF
GIFS-TIGGE WG February 2010

7. Daily TIGGE data archived at ECMWF
GIFS-TIGGE WG February 2010

8. TIGGE data retrieved from ECMWF
GIFS-TIGGE WG February 2010

9. TIGGE web pages ECMWF will continue to support TIGGE web site
Information available on site
Archive – how to access, what data is available
Data portal (will look at NetCDF for retrieval; some limitations)
Model documentation (updates required)
Monitoring (of data received and archived)
Add monitoring of usage?
GIFS-TIGGE WG (documents)
Add more background
Work done using TIGGE data
Papers, presentations (to update)
Links to other web sites (to be added)
GIFS-TIGGE WG February 2010

10. ECMWF TIGGE web site Static pages (intro, background); edited by ECMWF
Dynamic pages (automatic)
Monitoring
Dynamic pages (editable)
News, documentation
Can be edited (including adding docs) by users with administration rights
GIFS-TIGGE WG February 2010