The relationship between the North Atlantic Oscillation and meteo-oceanic parameters in the North Atlantic Ocean

Abstract

The North Atlantic Oscillation (NAO) is an intrinsic atmospheric process in the form of a dipolar pressure oscillation occurring over the North Atlantic Region. Nonetheless, its fluctuation can lead to atmospheric variability across the entire Northern Hemisphere, making it a prominent point of research in climate studies. This climatic manifestation is connected to several meteooceanic parameters (such as pressure at sea level, wind speed, and temperature at sea surface) on many different spatial and temporal scales. This study thus focuses on the understanding of these interactions by targeting three case studies: a positive North Atlantic Oscillation Index (NAOI) case study (+4; during December 2015), a negative NAOI case study (-5.1; during December 2010) and a control NAOI case study (+0.1; during July 2003). The Jones et al. (1997) methodology was used to calculate the NAOI for the respective time frames and the results show close similarity between graphical representations based on these calculations and those published by NOAA, making the methodology used a simple alternative for such studies. Moreover, raster analysis was used to analyse spatial data for various meteo-oceanic parameters generated by both numerical models and satellite remote sensing. Results show an enhancement of the sea level pressure gradient during December 2015, a weakening of the gradient during December 2010, whilst being in line with the climatological norm during July 2003. Regarding wind speed anomalies at the surface, these were strongly positive during December 2015, whilst being relatively negative during December 2010. Sea surface temperature anomalies were seen both at zerolag and preceding the NAO for both case studies, whilst identifying no pattern for the control case study. Furthermore, a negative relationship between wind speed anomalies and sea surface temperature anomalies have been observed throughout. All in all, this study should add value to the understanding of the complex dynamics between such variables and the NAO itself with the purpose of contributing to enhanced climatic research.