Priority Project "CORSO":
Consolidation of Operation and Research results for the Sochi Olympic Games

Last updated: March 2013

Project leaders: Gdaly Rivin and Inna Rozinkina (RosHydromet)


The 2014 Winter Olympics will be hold in Sochi, Russia. The Sochi region is very complicated for numerical modeling because of the complex surface properties determined by the proximity of the Black Sea combined with mountainous terrestrial conditions. The local mesoscale circulation causes numerous weather phenomena on the differently oriented mountain slopes and valleys. It challenges the requirements for the high resolution of the models to be used for the prediction of the meteorological conditions in the region; specific physical variables have to be predicted for different sporting events based on large amount of various observational and forecasting data.


A high number of weather hazards is annually registered in the Northern Caucasus especially in winter. In order to estimate their occurrence, an ensemble approach is also requested. The project plans an improved version of the COSMO weather forecasting model with a small grid and the improvement of post-processing methods targeted on delicate meteorological parameters (wind, snow cover, etc.).

The project CORSO aims to enhance and demonstrate the capabilities of COSMO-based numerical weather prediction systems for winter conditions in mountainous terrain and to demonstrate the practical use of this information during the Sochi-2014 Olympic Games. The peculiarity of the Sochi region justifies the development and adaptation of the currently available COSMO models. It assumes a development of modeling techniques, including data assimilation for near-surface and land-surface parameters, model physics and dynamical core, ensemble forecasting, post-processing and downscaling, comprehensive verification and other components, which are crucially important for the enhancement of the Sochi-2014 meteorological services.

Significantly the PP CORSO is aligned with the goals of the COSMO Science PLAN 2010-2014, where it is in particular stated (p. 11): "From the scale of the targeted processes it becomes clear that the mesh-size of the model system has to be of the order of 1- 2.2 km. The COSMO Steering Committee decided to focus on the development of a model-system for the short to very short range forecasting considering convective-scale resolution".

In the region of Sochi-2014 an additional observational network was developed since the end of 2011. It includes automatic stations for near-surface measurements, meteorological radars and aerological stations. This additional information can be used as a new source for data assimilation, model verification and for testing and adjust the algorithms.

The improvements introduced to the COSMO systems during the Olympic activity will be applicable to other regions with complex terrain and will benefit to the whole COSMO community.

The CORSO project can be considered as the COSMO-related part of the FROST-2014 project (FROST - Forecast and Research in the Olympic Sochi Testbed), initiated by WMO.

Actions proposed

Development of the COSMO model on the Sochi region characterized by complex terrain, irregular snow cover and sea proximity. Improvement of the operational forecasts based on the COSMO-Ru7 and COSMO-Ru2 models. Development of model version with resolution approximately 1 km. Identification of the gaps, adaptation of data assimilation techniques, analysis of numerical aspects using the high resolution and modification of parameterization schemes (Task1, 2.5 FTE/Year).

Development and adaptation of approaches for post-processing downscaling and possible forecasters feedback (Task 2, 1.2 FTE/Year).

Adjustment of the COSMO EPS's techniques (COSMO-LEPS) for the Sochi area and to specific requirements of winter Olympics. Development of COSMO-RuEPS system (Task 3, 1.1 FTE/Year).

All the developed systems and technologies have to be validated and made available to forecasters during trials well before the Olympics. Forecast products will be made available for Olympic forecasters via web-based tools.

Available expertise within COSMO

Links to other projects or work packages

Cooperation with all working groups will be required (as needed), during the lifetime of the project. Some type of works are supposed to be the development of activities, results and experience obtained in framework of PP COLOBOC (external parameters, snow cover investigations), verification tools (VERSUS2), improvement of turbulence schemes (UTCS).


The main risks are associated with the following factors:

Account of FTEs

It is not always possible to separate the tasks aimed directly support the Olympics from the tasks that can bring a value for the consortium. However, we envisage a good opportunity to bring value to entire COSMO community from the Olympic events meteorological supporting efforts. Therefore, the accounting of FTEs within COSMO project could not be too restrictive considering potential benefits to the entire project.

The resources required: 4.8 FTE/year


The project has been organized and devided in three major tasks:

TASK1: "High resolution COSMO-modeling for mountainous regions"

Task Leader is G.Rivin (Roshydromet), 2.5 FTE / Year

The pre-operational version of COSMO-Ru7/COSMO-Ru2 (grid step 2.2 km) for the North-Caucasian region was developed in Roshydromet in 2010-2011 (nesting into COSMO-Ru7 (without regional DAS). COSMO-Ru7 is based on the use of the initial data, received from the GME modeling system (20 km) of DWD and external parameters prepared as an output of the COSMO EXPAR system (2.2 km)).

Preliminary tests sometimes showed a presence of significant errors in meteorological fields predicted by the COSMO-Ru7/COSMO-Ru2 near land surface (primarily in air temperature, and as a consequence, conditions of boundary layer stability and the precipitation phase).

It was detected that certain inaccuracies in determining of the initial values of T2m, snow properties (the mask and water equivalent (WE)), as well as some external (geographic) parameters, such as mask and absolute height.

The goal of the starting actions of TASK1 is the identification of contribution of regional data assimilation for COSMO-Ru7 forecasting based on the comparison of scores of COSMO-Ru7 and COSMO-EU (with assimilation) for the area of COSMO-Ru7. In parallel the inclusion of nudging continuous cycle using all available data for both (COSMO-Ru7 and nested COSMO-Ru7/COSMO-Ru2) is expected. It will be based on the standard network measurement and new additional network in the Sochi region.
The technique of correction of T of upper soil levels based on the T2m measurements was previously developed in Roshydromet. It should be coupled with nudging continuous cycle and corrected snow mask from satellite observations.

The more precise modeling of the near surface meteorological parameters taking in the account the fractional relation of snow cover and stable and mosaic thermal stratification is one of the problems of numerical weather forecasting. It is obvious for future Sochi-2014 weather prediction. Previously, based on a study of the COSMO-Ru7 model forecasts for the large winter periods for the entire domain of COSMO-Ru7 it was revealed that the model produces the highest T2m errors in conditions of heating over the partial snow cover and some modification of TERRA was proposed and tested. TASK1 was expended to develop and test the modified algorithms of TERRA and to propose the modification of algorithms for turbulent diffuse parameterization scheme to improve the forecasts for certain cases.

The perspective plan of COSMO for 2014 stipulates the development of the 1-km modeling techniques. Some results were obtained by DWD, MeteoSwiss and ARPA-SIMC. The united efforts of COSMO partners focus on the steps that could potentially accelerate the development of the 1-km COSMO techniques.

The collaboration and coordination between DWD, MeteoSwiss, ARPA-SIMC, and Roshydromet is expected.

The task1 is divided in 2 subtasks:

Subtask 1.1: "Improvement of technology of deterministic forecasting of weather conditions with model resolution for the North-Caucasian area (Sochi-2014), (including the operational support)", with 1.9 FTE/Year.


Subtask 1.2: "Development of COSMO-Ru1", with 0.6 FTE/Year

TASK2: "Downscaling/post-processing for Sochi area and applications"

Task leader: I. Rozinkina, with 1.2 FTE/Year

The local values of meteoparameters for this region (coastal or mountainous clusters) may be provided only in post-processing, since the processes for specific parameters are not modeled explicitly even at high resolution.

Forecasting for the Olympic Games may be complicated by the necessity to predict parameters, which are not modeled directly (i.e., visibility, wind chill, hill fog etc). Furthermore it is requested that the exceeding of certain thresholds are accurately predicted (precipitation amount, fresh snow amount, visibility, wind, temperature, humidity, wind chill) in order to realize the possibility of open air competitions.

The goals of downscaling and post-processing methods are the following:

Following algorithms are presently available at Roshydromet: MOS on IFS/GFS (experimentally used also with COSMO-Ru7/WRF),training period: 1 year, linear regression of COSMO-Ru14 output for Altay mountains (training period: 2 weeks), empirical rules based on manual weather classification for forecasting of significant weather phenomena. This experience allows to develop the new techniques for the region of interest with more short (several days) training period, i.e Kalman filter techniques -firstly- for T2m at observational points improvement. As mentioned above, the experience of COSMO-countries in particular, in utilizing the Kalman filter correction techniques with similar weather conditions (subtropical mountains near sea - Switzerland, Italy, Greece) is very important.

The implementation of the automated weather classification systems together with climatic series of local observations can be used for forecasting relevant phenomena in the Sochi-2014 region. The previous results obtained in WG4 in the domain of conditional verification and the interpretation of model results will also be used.

The collaboration with MeteoSwiss and HNMS is expected.

Task2 includes two subtasks.

Subtask 2.1: "Adapted downscaling techniques for winter conditions in the mountains and IOC requirements" with 0.8 FTE/year


Subtask 2.2: "Determination of typical COSMO model inaccuracies for typical climatologic / synoptic situations, with 0.4 FTE/year

TASK3: "Development and adaptation of COSMO EPSs for the Sochi region"

Task leader: E.Astakhova (Roshydromet) and A. Montani (ARPA-SIMC), with 1.1 FTE/Year

Accurate assessment of probabilities of High-Impact Weather (HIW) events is the main challenge for regional ensemble prediction systems (EPS). For the winter Olympics, HIW are not necessarily linked with very intense or extreme meteorological phenomena. For outdoor sport events HIW forecasting also includes accurate representation of cross-zero temperature transitions (especially critical for cross-country skiing), precipitation phase and other sensible weather changes with respect to the prescribed decision-making thresholds. Development and demonstration of various HIW-related specific products is part of the ensemble component of the project CORSO.

COSMO-LEPS is an ensemble prediction system developed by the COSMO consortium. In the past years, COSMO-LEPS proved to be a valuable tool for the generation of probabilistic predictions of high-impact weather over complex topography and it is envisaged that it can be successfully used for the SOCHI region and provide useful support to bench forecasters during the Olympics. A 7-km COSMO-LEPS system for the Sochi region (COSMO-FROST-EPS) is to be developed within the framework of the project and will be used for operational support of Sochi-2014 Olympics.

EPS with higher than 7-km resolution is desirable for better probabilistic prediction over the complex Caucasus terrain. Within the RDP part of Task 3 CORSO, the development and testing of COSMO-Ru-LEPS with grid step 2.2 km is suggested.

COSMO-Ru2 for the North-Caucasian region already runs at Roshydromet. This technology is nested to COSMO-Ru7. On the other hand, COSMO-FROST-EPS (also with 7-km resolution) will run daily during pre-trials, trials and Olympics and can provide initial and boundary conditions (ICs and BCs) for a higher-resolution ensemble system. This gives a possibility to develop a 2.2 km EPS based on COSMO-Ru2 and ICs and BCs from SOCHMEL.

In collaboration and coordination with ARPA-SIMC (~0.35 FTE/year)/

Task3 consists of two subtasks:

Subtask 3.2: Development and verification of COSMO-Ru-LEPS 2.2 km for the Sochi region (with ICs and BCs from COSMO-FROST-EPS)


Subtask 3.1: Development and verification of COSMO-Ru-LEPS 2.2 km for the Sochi region (with ICs and BCs from COSMO-FROST-EPS)


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