Reason for establishment of Early Warning System for the occurrence of contamination due to bad weather in the region of Stara Zagora (EWS) are few cases registered with excessive concentrations (up to 8 times the maximum permissible concentration) of sulfur dioxide in Stara Zagora in 2004-2005 years became publicly known as "gassing of Stara Zagora". As a result of public outrage, as one of measures to overcome the "gassings" has provided development and construction of EWS. This is regulated in two Resolutions of 39 and 40 of the Republic of Bulgaria National Assembly, Order of the Regional Governor of Stara Zagora and Prescription RIEW - St. Zagora.
Entities of the project are three Thermal Power Plants in the region of "Maritsa East": Enel Maritza East 3 "," MARITZA EAST 2 "and" BRIKEL ".
Consortium "MSE" developed jointly by NIMH-BAS, conceptual design, which was adopted on an inter-ministerial technical advice during July 2005. From the end of 2005 started the construction of EWS, which is in two stages -the first in June 2006 and the second - in February 2007. In 2010 has extended the territorial scope of the EWS and included another TPP - AES Galabovo.
EWS was built as a fully automatic system. It works in "real time" in terms of assimilation of input information and generates twice a day hourly forecast at ground field of sulfur dioxide, nitrogen oxides and dust for the entire territory of Stara Zagora region in cells with horizontal dimensions of 3x3 km, in 12 layers (up to 2 km. height) and for 48 hours. This allows, in the presence of forecast to reach excessive levels of pollution, measures to be taken timely to reduce pollutant emissions from the chimneys of thermal power plants and to be avoided the "gassing".
EWS is a compound, an intelligent system. It consists of measuring, communications, computing and interface modules.It performed in "real time" measurements of meteorological parameters with four automatic weather stations MS&E-3RD and two MS&E-4 (AMC) located in the area, receive data on emissions of sulfur dioxide, nitrogen oxides and dust from all the chimneys of the three thermal power plants and data measured ground concentrations of these pollutants by four points in the field. Twice a day EWS receives prognostic data on meteorological parameters from a regional hydrostatic prognostic model cells with horizontal dimensions of 12x12 km. This prognostic information, together with current local weather data measured by the AMC, be assimilated by the local non-hydrostatic prognostic model, adapt and specify weather forecast for the area in the spatial dimensions of 3x3 km. This detailed numerical prognosis estimates with data on hourly emissions from the chimneys of thermal power plants is sent to the prognostic atmospheric diffusion model. It calculates the current and estimated concentration of sulfur dioxide, nitrogen oxides and dust in the region of Stara Zagora.
Due to large distances and different conditions at the sources of inputs for EWS communication medium is a hybrid. Data from the regional hydrostatic prognostic model resulting in high-speed Internet and have an intermediate processing in Sofia. They are then sent to the EWS-based Enel Maritza East 3. Also on the Internet is received the emission data from the three thermal power plants. AMC and instrumentation to measure immission are located on the field and data from them is carried by a digital radio channel.
For running the EWS are used two multiprocessor workstations (for parallel computing) and two powerful single-processor computer.The work of computing machines is synchronized and exchange the necessary data automatically over a LAN. There is developed user interface that allows the operator of EWS to monitor and if necessary to change modes. The software transfers the performance of the EWS automatically via Internet and they are viewed in real-time decision-makers in the three TPP Centrals, RIEW in Stara Zagora and the Crisis Staff in the Regional Administration of Stara Zagora.
With the capabilities and operation of EWS-spot met President of the Republic of Bulgaria, ministers and MPs. Its work is widely reflected in all national and local mass media. Since the commissioning of EWS in 2007 there has been more than ten cases of forced reduction of three thermal power plants due to the resulting estimate and was not committed any "gassing" of Stara Zagora.
