عنوان مقاله [English]
نویسنده [English]چکیده [English]
The ozone layer, as a life protective shield on the Earth, has attracted the man’s attention from various aspects. For the same reason, different dimensions of the ozone layer have been studied by researchers. The changeable amount of total ozone is affected by the sun, atmospheric elements, and climatological photochemical activities. Hence, the major amount of ozone is affected by atmospheric instability in the upper troposphere, and the atmospheric instability is united through the teleconnection patterns with climatic indices. Therefore, the total amount of ozone is connected to the climatic indices. The aim of this research is to study of climatic indices on the total ozone (TO) oscillations in Isfahan station.
According to this research, a 15-year daily statistics of total ozone (TO) in synoptic station and ozone evaluating in Isfahan from 1996 until the end of 2010 were used. The available defects in the ozone date using the satellite date from NASA/GSFC were obtained. Also, the data relating to NINO 1-4, SOI, NAO, AO and the wind blowing in the atmospheric various balances from NCEP/NCAR database were extracted and used. In this research the climatic indices were classified into the three categories. The first category is related to the remote teleconnection indices on the north hemisphere, of which the most important one include the North Atlas Oscillation (NAO) and the North Pole Oscillation (AO). The second category includes the south hemisphere teleconnection patterns. For this purpose, the SOI and NINO1-4 in the South Pacific Ocean were used. The third category includes the study of winds effect on the (TO) changes. Assuming that the effect of the wind waves natural (orbital or meridian) can affect the rich/poor ozone weather transfer. Therefore the effects of the wind blowing index in the level of 200mb on the (TO) changes in Isfahan were also studied. The levels height temperature of 10, 100 and 500mb were extracted and their relations with climatic indices and (TO) were studied. The correlative regressive analytical statistics were used for studying the relationship between the (TO) changes and climatic indices.
Results and Discussion
The relationship between the (TO) amount and reversed NAO and AO indices and during the cold months of December, January, & February comparing to other months is stronger. The AO correlative coefficients with the (TO) follow a logic process (reversed and regular in the cold months; Positive and irregular in the warm months), but this process is not seen in the NAO index. The relationship between the SOI index with the (TO) reversed and follow a specified monthly process. This relationship is significant at the 95% confident level. The NINO1-4 indices have a positive relationship with the (TO) changes, and its correlation follow a specified monthly process. The relationship of the (TO) amount with the NINO1-4 indices is significant in the cold months. Consequently, when the SOI index include the negative/positive amounts, the (TO) amount is increased/decreased. When the water level temperature indices is increased in the South Pacific Ocean, the (TO) amount is increased in Isfahan especially in the cold season. Various regressive models were tested in order to study the relationship of the (TO) with climatic indices in different months, from which the higher correlative coefficient was in February. The results show that the NINO1-4 and the SOI indices in the South Pacific Ocean explain more than 70% of (TO) changes in February, while the NAO and AO indices explain only 30% of the (TO) changes in the same month. The highest amount of (TO) monthly average have been 433DU occurring during a 15-year statistic course, when the SOI index bearing the lowest amount, and during the same time, the NINO1-4 showing the highest amount. The reversed, strong, and significant relationships of orbital wind blowing index in the level of 200mb with (TO) changes show that through the wind leading to meridian, the (TO) amount is increased strongly.
Studying the correlative relationships between the climatic indices and (TO) changes show a stronger correlation of the (TO) changes with climatic indices in the south hemisphere on the Pacific Ocean. These relationships are stronger and more significant in the cold seasons with the (TO) indices in Isfahan station. In such a manner among the entire studying indices, the SOI bear the best correlation with the (TO) amount. The most important effect of AO on the (TO) changes primarily is due to (TO) change affected by the polar (TO) changes. Transferring the polar ozone by the polar vertex to Isfahan is related to change in tropopause height. In this manner, when the AO index is being negated, the tropopause is increased, and the polar zone weather enriched with ozone is permitted to enter to Isfahan, and the ozone is increased. The relationship between the amount of AO and SOI indices with wind blowing index are negative and strong in the level of 200mb, and these relationships in the levels of 0.01 and 0.05 respectively are significant. Consequently, upon the AO and SOI are being negated, the wind blowing index is inclined towards the meridian.
Having regard to the fact that the (TO) amount bearing a strong and negative correlation in the level of 200mb with orbital wind blowing index, and by inclining to west winds leading to the meridian, the (TO) amount is increased over Isfahan. The Polar wind blowing index was affected by AO and SIO indices. The (TO) amount can be also affected by the negative relationship of the Polar wind blowing index with AO and SOI indices. Therefore the (TO) changes through wind blowing index is linked with AO and SOI indices.