The benefit of seamless forecasts for hydrological predictions over Europe
Two different systems provide long-range forecasts at ECMWF. On the sub-seasonal timescale, ECMWF issues an extended-range ensemble prediction system (ENS-ER) which runs a 46-day forecast integration issued twice weekly. On longer timescales, the current seasonal forecasting system (SYS4) produce...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-06-01
|
| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/22/3409/2018/hess-22-3409-2018.pdf |
| Summary: | Two different systems provide long-range forecasts at ECMWF. On the
sub-seasonal timescale, ECMWF issues an extended-range ensemble prediction
system (ENS-ER) which runs a 46-day forecast integration issued twice weekly.
On longer timescales, the current seasonal forecasting system (SYS4) produces
a 7-month outlook starting from the first of each month. SYS4 uses an older
model version and has lower spatial and temporal resolution than ENS-ER,
which is issued with the current operational ensemble forecasting system.
Given the substantial differences between the ENS-ER and the SYS4
configurations and the difficulties of creating a seamless integration,
applications that rely on weather forcing as input such as the European Flood
Awareness System (EFAS) often follow the route of the creation of two
separate systems for different forecast horizons. This study evaluates the
benefit of a seamless integration of the two systems for hydrological
applications and shows that the seamless system outperforms SYS4 in terms of
skill for the first 4 weeks, but both forecasts are biased. The
benefit of the new seamless system when compared to the seasonal forecast can
be attributed to (1) the use of a more recent model version in the
sub-seasonal range (first 46 days) and (2) the much more frequent updates of
the meteorological forecast. |
|---|---|
| ISSN: | 1027-5606 1607-7938 |