Advanced interpretation and verification of very high

resolution models

National Meteorological Administration 2007-2008

Rodica Dumitrache, Aurelia LUPASCU, Iulia IBANESCU

HYDROLOGICAL APLICATIONS

From May 2008, COSMO 4.0 is integrated in operational activity with the following characteristics:

•model domain cover Romanian territory

•domain resolution 7km

•grid points 161x145

•Runge-Kutta numerical scheme

•no data assimilation

•The model output was post-processed for being used as input data in CONSUL hydrological model.

•For this aim was made the interpolation procedure from rotated COSMO grid in latitude/longitude grid for 2m temperature and total precipitations fields.

•CONSUL is an deterministic mathematical model for continuous flowing for big and small hydrological catchments area

•The model could be used for flood forecast and also to simulate scenarios, in order to understood behavior of the hydrological system in severe situations.

• In this period several tests was performed with CONSUL using the COSMO model outputs for the hydrographic catchment Crisul Negru.

•The project was design to improve the quality of hydrological forecast, to inform, prevent and protect the population in critical flood situations, for a better management of water resources and also to minimizes the time and human resources allocated in forecast elaboration work.

Evaluation of high resolution model

•Verification scores was calculated for a period time between 1.06-30.06.2008, using the CVS verification package.

•The model was integrated for 7km and 2.8 km.

•The verification was made using SYNOP observations data.

Following parameters was evaluated:

-mean sea level pressure, 2m-temperature, wind speed at 10 m/s, precipitation.

Results 7 km resolution

Results 2.8 km resolution

CASE STUDIES

In this period was analyzed some cases with severe weather situation.

For illustration we choose 22 of April 2008 a tornado case in SE Europe

In the afternoon of 22 of April, a super cell produced a tornado in NE Bulgaria.

Few hours later a new super cell developed in the SE part of Romania, was detected by the Doppler radar (WSR 98D) installed at Medgidia.

The strong wind at ground, produced by the super cell, generated intense damage (over 200 houses lost the roofs, many up rooted trees). The super cell structure detected on the reflectivity field had all the classical features ( hook echo, intense reflectivity core over 60 dBZ, etc).

COSMO_RO 7km

In the wind field we can see clearly a good estimation of these two supercells. Development of the supercells at half hour difference.

COSMO_RO 2.8km

COSMO_RO 2.8 km estimate very well this extreme weather events as is illustrated in the wind field

The COSMO model run at 7km and 2.8 km resolution detected two very important structures for severe convective storms: at low level (wind at 10 m/s), a long convergence zone appear in the SE of Romania, where the super cells was initiated, and the outflow from the storms along the convergence line at high level – 300 hPa, the wind jet, that has a spectacular splitting just around the storm. This shows that the both versions of the COSMO model was able to “capture” the super cells .

This study show that the COSMO model at high resolution estimate very good the wind fields and the jet flow in severe weather situations, which was not predicted by the other numerical models.

CONCLUSIONS