NATIONAL INSTITUTE OF METEOROLOGY AND HYDROLOGY

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?????????? ???????? ?? ???????????? ?
?????????? NATIONAL INSTITUTE OF METEOROLOGY AND
HYDROLOGY ????????? ???????? ?? ???????

Bulgarian Academy of Science ???. ???????????
???? N 66 66 Tzarigradsko
Shosee boul ????? 1184
1184 Sofia, BULGARIA ???. 9753986,
??. 22490 rthsf bg tel. [phone],
tx.22490 rthsf bg ???? 9884494,9880380
fax.
3592 9884494, 9880380

• Recent Floods in Bulgaria. Information and
  Forecasting services
• Dobri Dimitrov
• Hydro-meteorological conditions in Bulgaria
• Hydro-meteorological observation network
• Extreme hydrological events, changing climate
• The floods in 2005
• Existing and desirable functionality of hydromt
  system
• Some conclusions

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Hydro-meteorological conditions in Bulgaria

• Three general zones
• Northern Bulgaria is on average more then one
  degree colder and receives annually about 190 mm
  precipitation more than
• Southern Bulgaria,
• Black Sea is too small to be a primary
  influencing factor of the country's weather it
  only affects a narrow zone along the sea cost

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Hydro-meteorological observation network
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Extreme hydrological events

• Severe draughts and floods
• Severe draughts came Bulgaria in early 90s
• Unusual floods struck large parts of the
  Bulgarian river basins in 2005

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Changing climate causing

• The annual distribution of precipitation and
  flow rates is changing
• The analysis of the cumulative probability
  distribution of annual maximums of daily
  precipitation totals shows dramatic
  irregularities

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The floods in 2005
14-28.02.2005 Snow coverage - 15.20 cm, up to
50cm, sstormy wind - 30 m/s, rainfall 80-150
mm/day. Water level raise15 16.02 at Arda
100-300 cm, Yantra and Kamchia 200-400 cm
Overflow of Ivaylovgrad dam about 800 m3/s. Big
flood in Turkey. 25-30.05, 06-08.06.2005 Converg
ent zone between high pressure field and
Maloasian cyclone with a high index of
fluctuation and the cyclone Iskar south of
the Alps, forming at noon and evening every day
massive convective systems. Frequent intensive
precipitation 50-180 mm, daily. The soils became
oversaturated in large areas hazardous floods in
Sofia region.
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01-04.07.2005 Cyclone Targovishte from the
northwest, cold front, convective systems -
torrential rainfalls. Pathways generated by
different mechanisms - overlapping. Daily
rainfall up to 250 mm. For the period between
2-14 July in the basins of Osam and Yantra rivers
rose more than 8 m. 04-08.08.2005 The most
devastating cyclone Ihtiman, relatively static
front line with intensive rainfalls. Convection
magnified by the relief. For the period
precipitation amount over the Marica river basin
is between 150-350 mm, daily maximums at Ihtiman
- 230mm 14-16.09, 18-23.09.2005 In the basins of
river Vit and Osum the precipitation was between
80-200 l/m2, During the period along river Yantra
- 150-260 l/m2, on 20.09 at Chernozemen 288
l/m2. At Shabla station Black Sea coast more than
360 mm for one week.
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An example of ALADIN forecast 5-8 august 2005
Observed precipitation
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Existing and desirable functionality of hydromt
system Existing
Improvements needed

• Semi quantitative 36 hours forecast of
  precipitation and other meteorological parameters
• Qualitative weekly forecast
• Indicative hydrological forecasting
• National level hydro-meteorological data
  collection and archiving
• Regional telecommunication centre SE Europe
• Regional hydro-meteorological education centre

• Reliability of the forecast.
• The lead time of the forecast, for the
  precipitation 10-15 days is possible if Bulgaria
  is a member of ECMWF.
• Better regionalisation of the forecast, more
  quantitative parameters.
• Operational hydrological modelling and
  forecasting at sensitive river basins.

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Some conclusions The hydrological extremes
observed during the last two decades in Bulgaria
are likely related to the changing climate.A
range of prevention measures is required like-
improvement of information systems, diagnostic
and forecasting services- drafting and
implementing of an adaptation strategy of various
economic sectors to the changing climate. Thank
you! Visit our Internet pages www.meteo.bg,
www.weather.bg, www.hydro.bg