Long-term changes in planetary wave and SSW parameters in the Northern Hemisphere

Sudden stratosphere warming (SSW) is a distinctive phenomenon characteristic of the winter stratospheric circulation. SSW is linked to the activity of planetary waves. Planetary waves are one of the most prominent waves in the stratosphere, and their evolution, propagation, and anomalies are critical scientific issues in atmospheric dynamics. This study primarily investigates the persistent trend changes in planetary waves and SSW-related climate indices within the stratosphere. Analyzing these trends to enhance the prediction of stratospheric atmospheric evolution. We conducted a zonal harmonic analysis using the potential height fields from ERA5, MERRA-2, and MLS satellite data to determine the amplitudes of planetary waves with wave numbers 1 to 3, analyzing a time period covers 40 winter-spring seasons in the Northern Hemisphere. Climatology for the last four decades allows us to reliably determine the average indicators that characterize zonal waves 1 – 3 during 4 months (December – March) in the stratosphere and lower mesosphere. We are looking for signs and possibilities of the SSW prediction by analyzing the trends of anomalous changes in planetary wave activity. We also discuss the trend changes in climate indices associated with stratospheric atmospheric dynamics, mainly focusing on El Nino Southern Oscillation, Arctic Oscillation, Equivalent Effective Stratospheric Chlorine, Quasi-Biennial Oscillation and NH Coupled Mode Index, over the 40 winter and spring season in the Northern Hemisphere from 1980 to 2023. We investigate the possible connections between these indices and SSW events to identify potential precursors associated with SSW. We try to find appropriate parameters that can trigger SSW. Therefore, the analysis of planetary wave parameters and climate indices can provide insights into SSW events' frequency and dynamic characteristics.