The effects of North Atlantic and Arctic oscillations over winter precipitation values of selected stations in Turkey

Abstract

The most effective component and element effective on the climate is the ocean current system. Especially, as a result of the scientific studies carried out by climate scientists in the last quarter of the 20th century, ocean currents are much more effective on the climate than it used to be thought. This current system creates some oscillations with the wind systems and the most popular one is the southern oscillation called el nino-la nina. Then in the 21st century, it has been claimed that not only southern oscillations have an effect on the climate systems but a serious of changes occuring in the North Atlantic have some effects as well on determining the climatic conditions of North hemisphere. Hence, as a result of the studies, it has been found out that it is effective on Europe, Mediterranean Basin and North East of North America. This oscillation is named North Atlantic Oscillation. In the subsequent studies, Arctic Oscillations which have a big effect on climate apart from NA Oscillations are studied. Climatic elements like temperature, pressure and precipitation differs year by year depending on the differences in atmospheric circulation on Earth and it has been found out that there is a relationship between the regions which are thought to have different climatic parameters. The simultaneous changes on different points on Earth have been recorded in meteorology literature for a long time ( Hurrel, 2003). These simultaneous changes are called Teleconnection in general. Besides, temperature levels might be below normal values from time to time in any part of the world while mild climate conditions might rule the other part of the world. One of the teleconnections in the middle and high latitudes in the North Hemisphere is North Atlantic Oscillation. This model is effective especially in winter in the North Hemisphere. North Atlantic Oscilation is effective from the Northeast coast of North America to Siberia region and from Arctic region to subtropical Atlantic region ( Hurrel, Kushnir, Visbeck,2001). On the other hand, North Atlantic Oscillation is defined as the reflection of the variability known as Arctic Oscillation (Hurrel, 2003). The most important point here is that the effect of Atctic Oscillation is very big on Atlantic Oscillation....................