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  Hungarian Meteorological Service  founded: 1870
Research and development | Numerical Weather Prediction  | Analysis of the Atmospheric Environment | 
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Laying the foundation of medium range weather forecasts using ECMWF model products


1 July 1994 Hungary became a co-operating state of the European Centre for Medium Range Weather Forecasts (ECMWF) as first country from Central Eastern European region. The basic aim of the forecasting centre is to provide medium range numerical weather forecasts of high quality. ECMWF is operationally running global deterministic and ensemble models covering the whole Earth. You can find comprehensive information about ECMWF and its activity on its web site. The Hungarian Meteorological Service (HMS) has access to the whole range of ECMWF's products as Hungary is co-operating state of this organization.

84 h forecast
Temperature forecast on 500 hPa pressure level as it is displayed on HAWK-2 visualization system of the HMS. 84 h forecast is valid for 00 UTC 24 November 2001


Numerical weather prediction models at the ECMWF


Deterministic model

At the ECMWF in Reading (United Kingdom) a 10 day deterministic model based on 00 and 12 UTC analysis is operationally launched twice a day. Hydrotermodynamic equations of deterministic model are solved by spectral method using spherical harmonics. The model is taking into account several physical interactions like ocean and atmosphere, soil wetness and atmosphere and snow covering and atmosphere.

The deterministic model contains 59 layers between surface and 0.1 hPa pressure level in the vertical, the resolution of model is about 40 km in space. In 2005 vertical resolution will be increased to 91 layers and horizontal resolution to 25 km.


Ensemble forecasts

Model errors are significantly growing in forecasting time due to the chaotic behaviour of the atmosphere and the insufficient initial observed data. Probability forecasts, so called ensemble forecasts are made by taking into account above mentioned effects. Using ensemble forecasting technique smaller perturbations are given on the initial field of the model above sensitive areas depending on weather situation. In this way the model is starting from initial conditions more or less different from original analysis. After several days the differences may become higher even if the initial differences were small.

The first 10-day probability forecasts could be made by using ensemble method in the end of 1992. Nowadays ensemble forecasts are operationally launched twice a day from 51 different initial states. The structure of ensemble forecast is very similar to the deterministic one, only the spatial resolution of the model is less in order to decrease the long computing time. Spatial resolution is recently about 80 km, in 2005 horizontal resolution will be increased to 50 km.

EPS plume forecastEPS meteogram forecast
EPS plume and meteogram forecast based on 00 UTC 14 February 2004


Monthly and seasonal forecasts

In last decade the results of the scientific researches could allow us to investigate influence of sea surface temperature anomalies on atmosphere. Lower boundary conditions - sea surface temperature, soil wetness and snow covering influence the state of the atmosphere. The El Nino phenomenon is significantly influencing the general circulation of the atmosphere. Using coupled ocean-atmosphere circulation models may extend the forecast range.

Predictability can be improved by two factors:

The development of measuring technique on equatorial areas of Pacific ocean can provide information on temperature in 500 m layer of upper ocean. Satellite measurements give huge amount of information about wind speed, temperature and humidity.

Numerical models drawing interactions between the ocean and the atmosphere were developed significantly the last several years.

Weekly forecasts of temperature anomalies
Weekly forecasts of temperature anomalies for the intervall between 15 February 2005 and 13 March 2005


ECMWF started experimental seasonal forecasts in 1995. The first quasi operational seasonal forecast was made in June 1998. The seasonal forecasting ensemble model contains 40 members and its spatial resolution is 200 km . Nowadays monthly forecast is made once a week, each Thursday and seasonal forecast is made once a month, 15. day of each month.

Seasonal EPS metogram valid from January to May 2005


Developing forecasts of extreme and severe events is one of the main aims of the long range (1999-2008) strategy plan of the ECMWF. Due to the fact that forecast of severe events is an important task of the HMS as well, strong co-operation was established and several investigations have been made in this respect. Verification of the so called Extreme Forecast Index (EFI) is operationally done for 2m temperature forecast, 10 m wind speed, 24h accumulated precipitation for the territory of Hungary.


EFI chart of 2m temperature valid for 12 UTC 10 February 2005
EFI chart of 2m temperature valid for 12 UTC 10 February 2005


Due to statictical investigation of the Extreme Forecast Index relliability of + 72, +96 and + 120 h ensemble forecast was surprisingly good during heat wave in summer 2000. It was proved in the case of the extreme events forecasts based on ensemble system is more reliable than deterministic forecast.


Use of the ECMWF's model products at the HMS

At the Hungarian Meteorological Service ECMWF model forecasts have been operationally used since 1995. ECMWF central data archive and wide range of developed ECMWF softwares are intensively used by the experts of the HMS, as we have free access to them based on the co-operating agreement between Hungary and ECMWF.

Our researchers and forecasters are regularly taking part in the educational and training programme of ECMWF, since 2000 we have had opportunity to take part in the work of ECMWF in Reading. Medium range forecasts displayed on the information web site of HMS are based on ECMWF model forecasts. Our several further services are also based on ECMWF forecasts. Some summary about the validation of forecasts are shown on the verification portal of NWP division.

Last few years several softwares were adapted and developed in our division. Among other products :

Plume: Ensemble plume made from all ensemble members shows probability in time, it can be made for any selected meteorological variable and any location. Its name comes from the shape of the figure. Figure shows all individual ensemble members (magenta lines), deterministic forecast (yellow line), control forecast (orange line) and ensemble mean (brown line).
Meteogram: Ensemble meteogram contains graphical forecast for cloudiness, 6 h precipitation, 10 m windspeed, 2m temperature for any selected location. Figure shows deterministic forecast (blue line), control forecast (red line) range (black vertical lines), lower and upper quartiles (green boxes) and median (black horizontal lines) of the ensemble.
Pseudo TEMP, forecast in the vertical: Deterministic model forecasts meterorological variables on 60 levels in the vertical. In the practice isobaric charts are usually used, but use of the vertical profile can be beneficial to study more precious structure of the atmoshere. Figure shows vertical profile of the temperature, humidity, wind direction and speed.
Clustering of the ECMWF ensemble forecasts made for Central European area: During clustering some groups (clusters) of the forecasts are made from 51 ensemble members, numbers of the clusters are typically two are three, maximum number can be six. Number of the clusters depends on predictability of the forecast. Nowadays clustering is made on 120 hours forecasts of the geopotential field of 500 hPa isobaric field. Cluster mean and representative member of each cluster is calculated.
Probabilities of sunshine: Table form and graphical forecasts valid for seven days are operationally daily made for giving guidance for energy suppliers and tourism.
Probabilities of global radiation: Table form and graphical forecasts valid for seven days are operationally daily made for giving guidance for energy suppliers and tourism.
Probabilities of wind gusts: Table form and graphical forecasts valid for seven days are operationally daily made for giving guidance for energy suppliers and storm warning system at Lake Balaton.
Seasonal forecasts: Table form and graphical temperature and precipitation forecasts valid for six regions of Hungary are operationally made monthly.
Further information can be found about seasonal forecasts: http://www.ecmwf.int/products/forecasts/seasonal/documentation/index.html


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