Climate

The climate suffers three exterior influences, as a result of the “buffer” position between the coterminous continental area surrounding it on the north, west and south sides, and the Black Sea in the east: the continental, Pontic influences and also those of the advection air (pendulating westward or eastward depending on the circulating air masses).

The total nebulosity. The annual average diminishes from the west (>5.6 tenths) to the east (< 5.2 tenths) where the smallest nebulosity is noticed.

The annual average duration of sunshine rises from the west to the east: Tulcea 2,260 hours of sunshine, Gorgova and Jurilovca 2,325 hours, Sfantu Gheorghe 2,502 hours.

The air temperature. Taking into account the exterior influences, the air temperature has moderate values, although in the shore area they are among the highest in the country.

The annual average values rise gradually from the west to the east, once with the diminution of the land influence and growth of the sea influence: Tulcea and Jurilovca 11.0ºC, Gorgova

11.2ºCsfantu Gheorghe and Gura Portitei 11.4ºC, Sulina-dam (situated above the territorial waters at about 6km far off the shore) 11.6ºC and Platform Gloria (situated at about 30km off the shore in front of the sea shore between Sfantu Gheorghe and Sulina) 12ºC, as a result of the thermal reservoir role played by the shallow waters (10-12m) on the continental platform.

The absolute extreme temperatures. The absolute minimum ones increase from the west to the east: Tulcea- 27.2ºC / 18 January 1963, Gorgova – 26.2ºC /18 January 1963, Sulina-town – 25.6ºC/ 9 February 1929, Jurilovca –23.5ºC/ 10 January 1940 and Sfantu Gheorghe –21.5ºC / 12 January 1950, while the absolute maximum ones rise from the east to the west: Sfantu Gheorghe – 36.3ºC / 9 July 1968, Sulina-town –37.5ºC / 20August 1946, Jurilovca – 38.0ºC / 8July 1968, Gorgova – 38.2ºC / 18 July, 1951 and Tulcea 39.7ºC / 20 August, 1945.

The air humidity. Owing to the numerous sources of evaporation and evapooerspiration on the DDBR territory, the annual average values are equal or higher than 75%. They rise from the west to the east: Jurilovca 76%, Tulcea and Gorgova 80%, Sulina 84% and Sfantu Gheorghe 86%.

The wind

The DDBR territory is one of the windiest zones from Romania. The depression shape, the large opening to the east, the absence of the orographic obstacles and the multitude of water lustres as well as the proximity to the Black Sea – important center of cyclogenesis are elements which condition the high frequency of winds, the high speeds and the reduced calm.

The predominant wind is from the north-west (Tulcea -15.4%, Gorgova -19.7%, Sfantu Gheorghe -17.5%), then the one from the north (Tulcea -12.3%, Gorgova -18.6%) and from the north-east (Sfantu Gheorghe -13.1%). In the shore area the wind from the north is dominant (Jurilovca -27.9%, Sulina -18.5%), followed by the one from the south (10.7% and 16.7% respectively), both of them being directed by the shore line. The same directions from the north and from the south are also dominant offshore, at the Platform Gloria, where the northern sector holds 44.8%.

The annual average speed on directions does not always have the maximum value on the dominant direction excepting the shore area (Sulina –8.4 m/s and Jurilovca –6.7 m/s); in the rest the higher speeds (4 – 5 m/s) are achieved on the north-east, the east and the south-east directions (from the sea).

The breezes, as a result of the thermo – barometric contrast between the water and the land, turn clockwise for 24 hours. The sea breeze acts by day between 10am and 8pm, and the land breeze acts by night between 11pm and 7am.

Meteorological risk

National Agency of Meteorology achieved research and studies of agro-meteorology in the context of new requirements of sustainable development. The figure below showing that humidity

resources of April- November period (observation period is from 19961 until 2000) are low Danube Delta. More specifically for mare then half of Danube Delta Reservation is included in droughty excessive category with <250mm precipitation. Other part is included in the second category of humidity namely droughty excessive with 251-300 precipitation.

Over Danube Delta and Razim Sinoe Complex where the warming is powerfully in the summer time and in the beginning of autumn the thermal convection is very active. The maximum of precipitation in 24 hours was registered in Danube Delta – C.A. Rosetti (530, 6 mm at august 30th

1924). This quaintly both with quantity registered a day before totalized 690, 6 mm which represent the biggest quantity of precipitation in short time from Romania.

The main characteristic of downpour is theirs intensity. In lower region this value is more than 6 mm/min, this value is lower with altitude till 3 mm/min in high region. In Romania, the biggest average values of this maximum pluvial intensity are present in lower plane regions characterized through continentalism, or to inferior limit of orographic barrage of Carpathians where the impact is more powerfully. The smallest values are between 3-4 mm/min ore smaller than 3 mm/min in some mountain area in Suceava Plateau, west of Somes Plateau and in Danube Delta and seacoast (especially north part) where are characterised descendent atmospheric movements. More details are presents in the figure below which correspond to soil humidity in the first 20 centimetres (different month). Therefore for Danube Delta the soil humidity in the first 20 cm is satisfactorily. At April 30th the situation changing as follows: in east, south – east and south of DDBR the soil humidity (the first 20 centimetres) is optimally, and is satisfactorily in other parts of DDBR. At 30th

of July the situation changing again – depth drought in the first 100 cm. Starting with July 30th _the

area from west, south –west and south of DDBR the soils are affected by depth draught in the first 100 centimetres.

In the figure below is presented winter violence between Mart 31st _{till November 1}st_{, 2004. The}

DDBR is characterised by low winter violence. This demonstrates that in this area the winters are mildly from lower temperature point of view.

In the figure below is presented the springtime coming situation. DDBR territory is totally included in the medium springtime coming (the period of studying was between February 1st _{– April 10}th

Climate change

The Law 11 /5 of June 1991 – No. 1 Article –“Romania adhered at United Nations Convention for desertification fighting in the country serious affected by drought, especially Africa, enacted at Paris June 17th _1994”.

The conditions at global level and subregion level – Romania

The climate data in the last century showing a progressive warming of atmosphere and reducing of precipitations quantity. All these have after- effects regarding agricultural production and water management. Along time the human economic activities modified the environment very much therefore many years ago Romanian territory was covered with forests -70-80%. Because of

deforestation of large territories for agricultural use, pastures, and economic activities the forests are covering in the present 29% of Romanian territory. Romania representing the first European country situated at north of 44 parallel that is affected by desertification. The causes for this situation are current clime changes (with serious effect of draught in the last ten years) and soils degradation. Meteorological data estimated for one hundred years are showing that 3 mil of hectares in Dobrogea , east of Muntenia and south of Moldova, from which 2,8 mil arable land (20% from agricultural Romanian territory), could by affected by desertification.

The area which could be affected by drought is larger (arable territory of Romania): Moldova Plateau, Transylvania Plateau, Getic Plateau, Trotus-Olt. The observations on long term are showing a tendency of aggravation of soils degradation on Romanian territory.

Causes and effects

Land degradation, desertification and draught are inseparable factors because of strength connection among them regarding theirs apparition, manifestation and long/short term consequences about environment and developing of human communities.

Phenomena as hydro erosion increasing draught in Dobrogea, Barlad Plateau, Getic Plateau, Danube River, Getic sub - Carpathians and Romana Plan, aeolian erosion having important effects about areas with sandy soils in south and south-eastern Romania (Oltenia, Bărăgan, Tecuci). Draught amplifies desertification and soils degradation.

Could be the climate, a decisive factor to increasing the stress of environment factors?

At global level finding out a transition period of climate because of green house effect – warming global process produced especially by carbon dioxide formed during combustions. Forests having an important role in carbon accumulation and theirs intense deforestation has generated the raising of carbon concentration of air.

In accordance with present research, if CO2 atmospheric emission wouldn’t decrease, in aprox 60 years the average temperature on Earth will increase with 3 degree. An increasing of average temperature with 0, 5 degree could generate large desertification (hundred of square kilometres and long seacoasts through increasing of ocean water level). Temperate climate characterized for our country now being in transformation, could change in tropical climate and that could generate important economical damages, and human heath consequences (good condition to expand tropical viruses as malaria).