Use of AMVs in the DWD model
Physical characteristics
Global Model
- Non-hydrostatic grid point model using a triangular (icosahedral) grid derived from a spherical projection of an icosahedron.
- Horizontal resolution: 2949120 triangular cells with an average resolution of 13.2 km.
- Vertical resolution: 120 layers.
- Analysis times: 00 03 06 09 12 15 18 21 UTC.
- Forecast range: 7 days.
Data assimilation method
Global Model
- Type: 3D-Ensemble-Var. Errors of the day information provided by global ensemble with 26 km resolution every 3 hours blended with climatological errors (currently contributing 25%).
- Time window: T ± 1,5 hrs.
- Time constraints (in UTC):
- Main forecast run: 2 hrs 20 min after 00 / 12
- Update runs: for 00 / 12: +11:30; for 03 / 15: +9:05; for 06 / 18: +6:35; for 09 / 21: +4:35
AMV tpes assimilated
Global Model
- Meteosat-9/-10/: IR10.8, HRVIS, VIS0.8, cloudy WV6.2, cloudy WV7.3.
- GOES-16/-18: IR3.8, IR, VIS, cloudy WV6.15.
- Himawari-9: IR, VIS, cloudy WV6.95.
- Metop-B/C BUFR IR single product.
- Metop-B/C BUFR IR dual product (B-C and C-B pairs only).
- CIMSS AVHRR NOAA-20/-21 IR.
- S-NPP VIIRS IR.
Global quality control
Blacklisting in space
- All winds reporting in height at or above 150 hPa.
- MSG WV, Himawari WV 6.7, and GOES WV below 400 hPa.
- All polar WV and CSWV winds below 600 hPa.
- All MSG IR, VIS and HRVIS winds below 600 hPa over land north of 0 degrees.
- All Himawari and GOES IR and visible winds below 600 hPa over land north of 20N.
- Low and mid level winds dependent on topography.
QI thresholds
The table below is intended only as a guide to the QI thresholds used.
Please see the section on blacklisting in space for specific details on which geographical areas are used.
| extratropics | tropics | |||||||
| HL | ML | LL | HL | ML | LL | |||
| GOES-16/18 | QI2 | IR | 90 | 90 | 90 | 90 | 90 | 90 |
| VIS | – | – | 90 | – | – | 90 | ||
| WV6.15 | 90 | – | – | 90 | – | – | ||
| Meteosat-9/10 | QI1 | IR | 85 | 90 | 85 | 85 | 90 | 85 |
| VIS0.8 | – | – | 65 | – | – | 85 | ||
| WV7.3 | 80 | 80* | – | 85 | – | – | ||
| WV6.2 | 80 | – | – | 85 | – | – | ||
| Himawari-9 | QI2 | IR | 85 | 85 | 87 | 85 | 86 | 85 |
| VIS | – | – | 85 | – | – | 85 | ||
| WV6.95 | 85 | – | – | 86 | – | – | ||
| Metop1/2/3 S-NPP NOAA-20/21 |
QI1 | IR | 50** | 50** | 50 | – | – | – |
*: only southern hemisphere; **: 60 for southern hemisphere
tropics: 20S-20N
extratropics: polewards of 20S/N
hl: 100-400 hPa
ml: 400-700 hPa
ll: 700-1000 hPa
QI1 – EUMETSAT QI with first guess check
QI2 – EUMETSAT QI without first guess check
Thinning
- All winds thinned in triangles with a horizontal distance of around 240 km and 100 hPa vertical resolution.
- Wind selected by highest QI, closest to analysts time and closest to the centre of the triangle.
- Winds are assimilated in 90 min time-slots.
Background check
- Comparison with 3h forecast from previous model run.
Observation errors
| 1000 hPa | 850 hPa | 700 hPa | 500 hPa | 400 hPa | 300 hPa | 250 hPa | 200 hPa | 150 hPa | 100 hPa | ||
| Meteosat-9/10 | NH | 1.8 | 2.0 | 2.0 | 3.0 | 3.6 | 3.6 | 3.4 | 3.6 | 4.0 | 4.0 |
| TR | 1.26 | 1.4 | 1.4 | 2.1 | 2.52 | 2.52 | 2.38 | 2.52 | 2.8 | 2.8 | |
| SH | 1.8 | 2.0 | 2.0 | 3.0 | 3.6 | 3.6 | 3.4 | 3.6 | 4.0 | 4.0 | |
| GOES-16/18 | NH | 1.92 | 2.16 | 2.88 | 3.96 | 4.2 | 4.44 | 4.68 | 4.8 | 4.8 | 4.8 |
| TR | 1.6 | 1.8 | 2.4 | 3.3 | 3.5 | 3.7 | 3.9 | 4.0 | 4.0 | 4.0 | |
| SH | 2.4 | 2.7 | 3.6 | 4.95 | 5.25 | 5.55 | 5.85 | 6.0 | 6.0 | 6.0 | |
| Himawari-9 | NH | 1.6 | 1.8 | 2.4 | 3.3 | 3.5 | 3.7 | 3.9 | 4.0 | 4.0 | 4.0 |
| TR | 1.4 | 1.4 | 1.4 | 2.17 | 2.45 | 2.59 | 2.73 | 2.8 | 2.8 | 2.8 | |
| SH | 2.0 | 2.0 | 2.0 | 3.1 | 3.5 | 3.7 | 3.9 | 4.0 | 4.0 | 4.0 | |
| METOP/NOAA | all | 3.0 | 2.5 | 2.5 | 2.5 | 3.0 | 4.0 | 4.0 | 4.5 | 5.0 | 5.0 |
| S-NPP | all | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 | 3.0 | 4.0 | 4.0 | 5.0 | 5.0 |
Error values in m/s